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Sample records for calcium ionophore a23187

  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...

  2. Calcium ionophore (A-23187 induced peritoneal eicosanoid biosynthesis: a rapid method to evaluate inhibitors of arachidonic acid metabolism in vivo

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    T. S. Rao

    1993-01-01

    Full Text Available The present investigation characterizes calcium ionophore (A-23187 induced peritoneal eicosanoid biosynthesis in the rat. Intraperitoneal injection of A-23187 (20 μg/rat stimulated marked biosynthesis of 6-keto-PGF1α (6-KPA, TxB2, LTC4 and LTB4, with no detectable changes on levels of PGE2. Levels of all eicosanoids decreased rapidly after a peak which was seen as early as 5 min. Enzyme markers of cellular contents of neutrophils and mononuclear cells, MPO and NAG respectively, decreased rapidly after ionophore injection; this was followed by increases after 60 min. Indomethacin, a selective cyclooxygenase inhibitor, and zileuton and ICI D-2138, two selective 5-lipoxygenase inhibitors attenuated prostaglandin and leukotriene pathways respectively. Oral administration of zileuton (20 mg/kg, p.o. inhibited LTB4 biosynthesis for up to 6 h suggesting a long duration of pharmacological activity in the rats consistent with its longer half-life. The rapid onset and the magnitude of increases in levels of eicosanoids render the ionophore induced peritoneal eicosanoid biosynthesis a useful model to evaluate pharmacological profiles of inhibitors of eicosanoid pathways in vivo.

  3. Immunodeficiency after allogeneic bone marrow transplantation in man. Effect of phorbol ester (phorbol myristate acetate) and calcium ionophore (A23187) in vitro

    DEFF Research Database (Denmark)

    Møller, J; Hofmann, B; Langhoff, E

    1989-01-01

    that the proliferative response of patient cells was reduced both when the cells were stimulated with phytohaemagglutinin (PHA) and when they were stimulated with a combination of phorbol myristate acetate (PMA), which is an activator of protein kinase C (PKC), and the calcium ionophore A23187, which irreversibly opens...

  4. Mechanism of histamine release from rat mast cells induced by the ionophore A23187: effects of calcium and temperature

    DEFF Research Database (Denmark)

    Johansen, Torben

    1978-01-01

    1 The mechanism of histamine release from a pure population of rat mast cells induced by the lipid soluble antibiotic, A23187, has been studied and compared with data for anaphylactic histamine release reported in the literature. 2 Histamine release induced by A23187 in the presence of calcium 10...

  5. A general method, employing arsenazo III in liposomes, for study of calcium ionophores: results with A23187 and prostaglandins.

    Science.gov (United States)

    Weissmann, G; Anderson, P; Serhan, C; Samuelsson, E; Goodman, E

    1980-01-01

    Multilamellar (MLV) and large unilamellar (LUV) lipid vesicles (liposomes) trap the metallochromic dye arsenazo III [2,7-bis(arsonophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid ] in their aqueous compartments. When ionophore A23187 was preincorporated into either MLV or LUV above 0.001 mol%, addition of Ca to the outside of liposomes produced spectral shifts characteristic of the Ca . AIII2 complex. The method permitted detection of two molecules of A23187 per liposome. Liposomes with A23187 were permselective: divalent cations were translocated in the order Mn greater than Ca greater than Sr greater than Mg congruent to Ba. Because prostaglandins (PGs) may act as Ca ionophores, we have incorporated into MLVs and LUVs stable prostaglandins (PGE2, PGI2, PGB1), endoperoxide analogs, and a water-soluble, polymeric derivative of PGB1:PGBx. None acted as ionophore. In contrast, when added to the outside of preformed MLV or LUV, PGBx, at concentrations above 1 micro M, provoked permselective uptake of Ca equivalent to that induced by 10 nM A23187. These studies demonstrate not only that liposomes containing arsenazo III may be employed in a sensitive asssay for agents that translocate divalent cations, but that a water-soluble derivative of a naturally occurring fatty acid, PGBx, is a potent ionophore. PMID:6769114

  6. Calcium ionophore A23187 specifically decreases the secretion of beta-secretase cleaved amyloid precursor protein during apoptosis in primary rat cortical cultures

    DEFF Research Database (Denmark)

    Sennvik, K; Benedikz, Eirikur; Fastbom, J

    2001-01-01

    - and gamma-secretase cleavage. Alternatively, APP may be cleaved within the A beta region by alpha-secretase, preventing A beta formation. Here we investigated APP processing and secretion in primary neurons, using either colchicine or the calcium ionophore A23187 to induce apoptosis. Cell viability...... beta sAPP) did not change. In addition, caspase inhibition restored cell viability to control levels. Exposure to colchicine did not change the amount of either secreted beta-sAPP or total sAPP and caspase inhibition was only partially able to restore cell viability. We conclude that calcium...

  7. Utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187

    DEFF Research Database (Denmark)

    Johansen, Torben

    1979-01-01

    The role of endogenous adenosine triphosphate (ATP) in histamine release from rat mast cells induced by the ionophore A23187 in vitro has been studied. 2 The amount of histamine released by calcium from rat mast cells primed with the ionophore A23187 was dependent on the ATP content of the mast...

  8. Three-day-old human unfertilized oocytes after in vitro fertilization/intracytoplasmic sperm injection can be activated by calcium ionophore a23187 or strontium chloride and develop to blastocysts.

    Science.gov (United States)

    Liu, Ying; Han, Xiao-Jie; Liu, Ming-Hui; Wang, Shu-Yu; Jia, Chan-Wei; Yu, Lan; Ren, Guoqing; Wang, Li; Li, Wei

    2014-08-01

    Our objective was to observe the effectiveness of the calcium ionophore A23187 or strontium chloride on the activation and subsequent embryonic development of 3-day-old human unfertilized oocytes after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). A total of 279 3-day-old unfertilized oocytes after IVF or ICSI were randomized to be activated by the calcium ionophore A23187 (n=138) or strontium chloride (n=141). The activated oocytes were cultured in vitro for 3-5 days. Activation rate, pronucleus formation, cleavage rate, and developmental potential of parthenotes during culture were evaluated. A total of 170 unfertilized oocytes were activated; 65 developed to cleavage stage, 19 developed to greater than the eight-cell stage, and five blastocysts were obtained. The activation rate of the calcium ionophore A23187 group was higher than that of the strontium chloride group (75.4% and 46.8%, respectively; pstrontium chloride group, six developed to the two- to four- cell stage, 10 developed to the five- to eight-cell stage, four developed to greater than the eight-cell stage, and one blastocyst was obtained. Three-day-old unfertilized human oocytes after IVF or ICSI could be activated by the calcium ionophore A23187 or strontium chloride, and a small part of parthenogenetic embryos developed into blastocysts. The treatment with the calcium ionophore A23187 was better than that of strontium chloride in respect to the activation rate of 3-day-old unfertilized human oocytes after IVF or ICSI.

  9. Effect of heparin, caffeine and calcium ionophore A23187 on in vitro induction of the acrosome reaction of fresh ram spermatozoa

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    K.H. El-Shahat

    2016-04-01

    Conclusion: The best concentration of heparin, caffeine and ionophore A23187 are 75 μg/mL, 1 mg/mL, 1.55 mM/mL for 3, 1, 4 h incubation respectively and can be used for in vitro fertilization in sheep.

  10. Stimulation of AIDS lymphocytes with calcium ionophore (A23187) and phorbol ester (PMA): studies of cytoplasmic free Ca, IL-2 receptor expression, IL-2 production, and proliferation

    DEFF Research Database (Denmark)

    Hofmann, B; Moller, J; Langhoff, E

    1989-01-01

    the PHA-induced rise of cytoplasmic free calcium concentration ([Ca2+]1) in normal and AIDS lymphocytes was observed. The percentage of cells expressing IL-2 receptors (CD25) was also normal both after addition of PHA and after addition of A23187/PMA and the expression was normal on both CD4 and CD8 cells....... The production of IL-2 in normal lymphocytes stimulated with A23187/PMA was 33 times higher than that after stimulation with PHA. In AIDS lymphocytes the production of IL-2 induced by all activators was severely decreased compared to control subjects, although the production of IL-2 after stimulation with A23187...

  11. Mechanism and specificity of lanthanide series cation transport by ionophores A23187, 4-BrA23187, and ionomycin.

    Science.gov (United States)

    Wang, E; Taylor, R W; Pfeiffer, D R

    1998-01-01

    A23187, 4-BrA23187, and ionomycin transport several lanthanide series trivalent cations at efficiencies similar to Ca2+, when compared at cation concentrations of approximately 10(-5) M, ionophore concentrations of approximately 10(-6) M, and a pH of 7.00. Selectivity sequences and the range of relative rates are as follows: A23187, Nd3+ > La3+ > Eu3+ > Gd3+ > Er3+ > Yb3+ > Lu3+ (approximately 34-fold); 4-BrA23187, Nd3+ > Eu3+ > Gd3+ > La3+ > Er3+ > Yb3+ > Lu3+ (approximately 34-fold); ionomycin, La3+ > Yb3+ > Nd3+ > Lu3+ > Er3+ > Eu3+ > Gd3+ (approximately 4-fold). At concentrations between 9 and 250 microM, La3+ is transported by an electroneutral mechanism, predominately through mixed complexes of the type (ionophore)2La-OH (A23187 and 4-BrA23187) or (ionophore)La-OH (ionomycin), when no membrane potential is present. For all three ionophores, an induced potential of approximately 160 mV accelerates transport by approximately 50-100%. However, measured values of H+/La3+ exchange indicate that only 4-BrA23187 displays a significant electrogenic activity under these conditions. At a La3+ concentration of 17 mM, transport by all three ionophores is electroneutral and apparently occurs through complexes of type (ionophore)3La (A23187 and 4-BrA23187) or (ionophore)La-OH (ionomycin). Analysis of these patterns in a context of comproportionation equilibria involving the transporting species and free La3+ indicates that the species containing three ionophore molecules are formed on the membrane when aqueous phase solution conditions would strongly favor a 1:1 complex, based upon previous studies in solution. The implications of this and other findings are discussed. PMID:9726927

  12. Andrographolide suppresses thymic stromal lymphopoietin in phorbol myristate acetate/calcium ionophore A23187-activated mast cells and 2,4-dinitrofluorobenzene-induced atopic dermatitis-like mice model

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    Li CX

    2016-02-01

    Full Text Available Chun-xiao Li,* Hua-guo Li,* Hui Zhang,* Ru-hong Cheng, Ming Li, Jian-ying Liang, Yan Gu, Bo Ling, Zhi-rong Yao, Hong Yu Department of Dermatology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Atopic dermatitis (AD is one of the most common inflammatory cutaneous diseases. Thymic stromal lymphopoietin (TSLP has been demonstrated to be an important immunologic factor in the pathogenesis of AD. The production of TSLP can be induced by a high level of intracellular calcium concentration and activation of the receptor-interacting protein 2/caspase-1/NF-κB pathway. Andrographolide (ANDRO, a natural bicyclic diterpenoid lactone, has been found to exert anti-inflammatory effects in gastrointestinal inflammatory disorders through suppressing the NF-κB pathway. Objective: To explore the effect of ANDRO on the production of TSLP in human mast cells and AD mice model. Methods: We utilized enzyme-linked immunosorbent assay, real-time reverse transcription polymerase chain reaction analysis, Western blot analysis, and immunofluorescence staining assay to investigate the effects of ANDRO on AD. Results: ANDRO ameliorated the increase in the intracellular calcium, protein, and messenger RNA levels of TSLP induced by phorbol myristate acetate/calcium ionophore A23187, through the blocking of the receptor-interacting protein 2/caspase-1/NF-κB pathway in human mast cell line 1 cells. ANDRO, via oral or local administration, also attenuated clinical symptoms in 2,4-dinitrofluorobenzene-induced AD mice model and suppressed the levels of TSLP in lesional skin. Conclusion: Taken together, ANDRO may be a potential therapeutic agent for AD through suppressing the expression of TSLP. Keywords: atopic dermatitis, thymic stromal lymphopoietin, andrographolide, human mast cell

  13. Formation of hybrid complexes between Ca2+ and the ionophores bromolasalocid (Br-X537A) and A23187

    OpenAIRE

    Deleers, Michel; Gelbcke, Michel; Malaisse, Willy J

    1981-01-01

    The ionophores A23187 and bromolasalocid (Br-X537A) acted synergistically in translocating Ca2+ from an aqueous into an organic immiscible phase or in mediating Ca2+ transport across the organic phase, the effects obtained in the simultaneous presence of both ionophores being greater than those expected from a summation of the individual effects of each ionophore. The nuclear magnetic resonance spectrum obtained when the complexation of Ca2+ occurred in the presence of both ionophores differe...

  14. Inhibition of "spontaneous," notochord-induced, and collagen-induced in vitro somite chondrogenesis by the calcium lonophore, A23187.

    Science.gov (United States)

    Kosher, R A

    1978-02-01

    The present study represents a first step in investigating the possible involvement of calcium (Ca2+) in the stimulation of somite chondrogenesis elicited by extracellular matrix components produced by the embryonic notochord. The ionophore, A23187, a drug that facilitates Ca2+ uptake leading to elevation of cytoplasmic Ca2+ levels, at concentrations of 0.25-1.0 microgram/ml severely impairs "spontaneous" somite chondrogenesis, i.e., inhibits the formation of the small amount of cartilaginous matrix normally formed by embryonic somites in vitro in the absence of inducing tissues. This inhibition is reflected in a considerable reduction in sulfated glycosaminoglycan (GAG) accumulation by A23187-treated somite explants. Furthermore, A23187 inhibits the striking stimulation of cartilaginous matrix formation and sulfated GAG accumulation normally elicited by the embryonic notochord and collagen substrates. In fact, 1.0 microgram/ml of A23187 reduces sulfated GAG accumulation by somites cultured in association with notochord or on collagen to a level even below that accumulated by somites cultured in the absence of these inductive agents. Although these results must be interpreted with caution, they provide incentive for considering a possible regulatory role for Ca2+ in the chondrogenic response of somites to extracellular matrix components produced by the embryonic notochord.

  15. Effects of pH conditions on Ca2+ transport catalyzed by ionophores A23187, 4-BrA23187, and ionomycin suggest problems with common applications of these compounds in biological systems.

    Science.gov (United States)

    Erdahl, W L; Chapman, C J; Taylor, R W; Pfeiffer, D R

    1995-01-01

    Phospholipid vesicles loaded with Quin-2 and 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) have been used to investigate the effects of pH conditions on Ca2+ transport catalyzed by ionophores A23187, 4-BrA23187, and ionomycin. At an external pH of 7.0, a delta pH (inside basic) of 0.4-0.6 U decreases the rate of Ca2+ transport into the vesicles by severalfold under some conditions. The apparent extent of transport is also decreased. In contrast, raising the pH by 0.4-0.6 U in the absence of a delta pH increases both of these parameters, although by smaller factors. The relatively large effects of a delta pH on the transport properties of Ca2+ ionophores seem to reflect a partial equilibration of the transmembrane ionophore distribution with the H+ concentration gradient across the vesicle membrane. This unequal distribution of ionophore can cause a very slow or incomplete ionophore-dependent equilibration of delta pCa with delta pH. A second factor of less certain origin retards full equilibration of delta pCa when delta pH = 0. These findings call into question several ionophore-based methods that are used to investigate the regulatory activities of Ca2+ and other divalent cations in biological systems. Notable among these are the null-point titration method for determining the concentration of free cations within cells and the use of ionophores plus external cation buffers to calibrate intracellular cation indicators. The present findings also indicate that the transport mode of Ca2+ ionophores is more strictly electroneutral than was thought, based upon previous studies. PMID:8599641

  16. Synergistic effects of hypoglycaemic sulphonylureas and antibiotic ionophores upon calcium translocation.

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    Couturier, E.; Malaisse, W. J.

    1980-01-01

    1 Hypoglycaemic sulphonylureas, such as tolbutamide and gliclazide, provoke the translocation of calcium from an aqueous medium into or across a hydrophobic region. The combined effect of sulphonylureas and antibiotic ionophores upon such a process was investigated. 2 The magnitude of the sulphonylurea-induced translocation of calcium was more marked in the presence than in the absence of A23187. Gliclazide and tolbutamide also enhanced, although less markedly, X537A-mediated calcium translocation. The effect of the sulphonylureas was even less marked in the presence of both ionophores, which acted synergistically in causing calcium translocation. 3 A non-hypoglycaemic sulphonylurea and diazoxide failed to affect ionophore-mediated calcium translocation. Gliclazide failed to enhance X537A-mediated sodium translocation. 4 It is proposed that the primary site of action of hypoglycaemic sulphonylureas upon calcium-dependent physiological processes may correspond to a drug-induced facilitation of calcium transport across the plasma membrane, as mediated by native ionophores. PMID:6781574

  17. Further observations on the utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187

    DEFF Research Database (Denmark)

    Johansen, Torben

    1980-01-01

    in the adenosine triphosphate (ATP) content and the rate of lactate production of A23187-primed mast cells. 3 Ethacrynic acid by itself decreased the rate of glycolytic ATP production. 4 By measurement of the ATP content and the lactate production of mast cells with or without secretory activity, the increased...... demand of energy for exocytosis was estimated to be equivalent to 0.14 pmol of ATP pr 10(3) mast cells....

  18. Activation and proliferation signals in mouse B cells. VII. Calcium ionophores are non-mitogenic polyclonal B-cell activators.

    Science.gov (United States)

    Klaus, G G; Bijsterbosch, M K; Holman, M

    1985-01-01

    Calcium ionophores cause polyclonal proliferation of lymphocytes from man, rabbit and pig, but are not mitogenic for mouse T or B lymphocytes. We show here that two Ca2+ ionophores (A23187 and ionomycin) nonetheless activate a substantial proportion of mouse B lymphocytes at concentrations which effectively inhibit DNA synthesis induced by conventional mitogens, such as anti-immunoglobulin antibodies. Activation of B cells was detected by (i) increased expression of Ia antigen after 24 hr culture with ionophores, and (ii) the accelerated onset of DNA synthesis in B cells primed with ionophores for 24 hr, washed and then rechallenged with anti-Ig. Unlike anti-Ig, the ionophores did not induce either the breakdown of inositol phospholipids, or RNA synthesis in B cells. Finally, activation of B cells by ionophores is highly susceptible to inhibition by cyclosporine. These results therefore suggest that elevation of intracellular Ca2+ induced by these ionophores is sufficient to cause B cells to leave Go, but not to enter the G1 phase of the cell cycle. Clearly, additional signals are required for B cells to progress further into cycle and eventually become committed to DNA synthesis. PMID:2414214

  19. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

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

    1993-01-01

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

  20. Arachidonic and eicosapentaenoic acid metabolism in bovine neutrophils and platelets: effect of calcium ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, S.M.; Laegreid, W.W.; Heidel, J.R.; Straub, K.M.; Liggitt, H.D.; Silflow, R.M.; Breeze, R.G.; Leid, R.W.

    1987-09-01

    Substitution of dietary fatty acids has potential for altering the inflammatory response. The purpose of the present study was to define the metabolites of arachidonic acid (AA) and eicosapentaenoic acid (EPA) secreted by bovine peripheral blood neutrophils and platelets. High performance liquid chromatography was used to characterize cyclooxygenase and lipoxygenase metabolites secreted in response to the calcium ionophore A23187. Cells were prelabelled with /sup 3/H-AA or /sup 3/H-EPA prior to challenge with the calcium ionophore. Bovine neutrophils secreted leukotriene B4 (LTB4) and 5-hydroxyeicosatetraenoic acid (5-HETE) as the major metabolites of AA, as well as the corresponding leukotriene B5 (LTB5) and 5-hydroxyeicosapentaenoic acid (5-HEPE) metabolites of EPA. Peptidoleukotrienes derived from /sup 3/H-AA or /sup 3/H-EPA were not detected under these conditions. The major tritiated metabolites secreted from bovine platelets were: thromboxane A2, measured as the stable metabolite thromboxane B2 (TXB2); hydroxyheptadecatrienoic acid (HHT) and 12-HETE derived from /sup 3/H-AA; and the omega-3 analogs TXB3 and 12-HEPE, derived from /sup 3/H-EPA. Preferred substrate specificities existed amongst the AA- and EPA-derived metabolites for the intermediary enzymes involved in the arachidonic acid cascade. These findings support the hypothesis that substitution of membrane-bound AA by EPA has potential for modulation of the host inflammatory response following cellular phospholipid mobilization.

  1. Ionophores stimulate prostaglandin and thromboxane biosynthesis*

    Science.gov (United States)

    Knapp, Howard R.; Oelz, Oswald; Roberts, L. Jackson; Sweetman, Brian J.; Oates, John A.; Reed, Peter W.

    1977-01-01

    The role of calcium in triggering prostaglandin and thromboxane synthesis was studied in several systems with ionophores of different ion specificities. Divalent cationophore A23187 stimulates prostaglandin and thromboxane production by washed human platelets in a concentration-dependent manner (0.3-9 μM). A23187 also induces an antimycin A-insensitive burst in oxygen utilization which is partially blocked by 5 mM aspirin or 10 μM indomethacin. Under our conditions, A23187 (up to 10 μM) does not appear to damage platelet membranes since it does not cause appreciable loss of lactate dehydrogenase or β-glucuronidase. Mono- and divalent cationophore X537A also stimulates platelet thromboxane B2 production and oxygen utilization, but monovalent cationophores nigericin, monensin A, A204, and valinomycin have no effect. The synthesis of prostaglandins E2, D2, and F2α by rat renal medulla mince is stimulated by 1 and 5 μM A23187 without changes in tissue ATP content, lactate output, or K+ efflux. X537A, monensin A, and nigericin (all 5 μM) stimulate both prostaglandin output and K+ efflux from renal medulla, while 5 μM valinomycin or A204 has no effect on either. None of the ionophores stimulates renomedullary prostaglandin production if calcium is omitted from the incubation medium. A23187 also stimulates prostaglandin production by human lymphoma cells, rat stomach and trachea preparations, and guinea pig polymorphonuclear leukocytes. These observations suggest a major role for Ca2+ in stimulating prostaglandin and thromboxane biosynthesis, and also indicate that prostaglandin and/or thromboxane release may partially mediate some of the previously described effects of ionophores on cells and tissues. PMID:270668

  2. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B

    1996-01-01

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

  3. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B

    1996-01-01

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

  4. Carboxylic Acid Ionophores as Probes of the Role of Calcium in Biological Systems

    Science.gov (United States)

    Reed, P. W.

    1983-01-01

    The biological effects of calcium ionophores are described, focusing on arachidonic acid oxygenation, and the formation of a number of oxygenated metabolites of arachidonic acid. These metabolites are involved in a number of bodily functions, and their production may be regulated by calcium.

  5. Can calcium ionophore "use" in patients with diminished ovarian reserve increase fertilization and pregnancy rates? A randomized, controlled study.

    Science.gov (United States)

    Caglar Aytac, Pinar; Kilicdag, Esra Bulgan; Haydardedeoglu, Bulent; Simsek, Erhan; Cok, Tayfun; Parlakgumus, Huriye Ayse

    2015-11-01

    To determine whether calcium ionophore solution can improve the fertilization rate in patients with diminished ovarian reserve whose partners have normal sperm parameters. Between January 2014 and August 2014, patients with diminished ovarian reserve were randomized to make artificial oocyte activation with calcium ionophore solution. University hospital. A total of 296 patients who had diminished ovarian reserve and partners with normal sperm parameters were included in the study. Metaphase 2 oocytes were treated with calcium ionophore solution (GM508 Cult-Active) for 15 minutes just after intracytoplasmic sperm injection. Fertilization rate, implantation rate, clinical pregnancy rate, ongoing pregnancy rate. Fertilization, implantation, pregnancy, and ongoing pregnancy rates for the calcium ionophore and control groups were 60.7% and 55.4%, 12.8% and 10.7%, 21% and 12.8%, and 10.9% and 6.1%, respectively. This is the first prospective, randomized, controlled study to analyze the effect of calcium ionophore solution on fertilization rate in patients with diminished ovarian reserve. We did not observe any differences in fertilization, clinical pregnancy, or ongoing pregnancy rates between the groups. We propose that fertilization ratios could not be increased by artificial oocyte activation via application of calcium ionophore solution in patients with diminished ovarian reserve. NCT02045914. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    1987-01-01

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

  7. Does the use of calcium ionophore during artificial oocyte activation demonstrate an effect on pregnancy rate? A meta-analysis.

    Science.gov (United States)

    Murugesu, Sughashini; Saso, Srdjan; Jones, Benjamin P; Bracewell-Milnes, Timothy; Athanasiou, Thanos; Mania, Anastasia; Serhal, Paul; Ben-Nagi, Jara

    2017-09-01

    To study the effect, if any, of calcium ionophore as a method of artificial oocyte activation (AOA) on pregnancy outcomes and fertilization rates. Meta-analysis of randomized controlled trials, prospective observational and retrospective trials, case reports, and a case-control trial. University-affiliated teaching hospital. Infertile couples undergoing fertilization treatment. Use of calcium ionophore during AOA. Odds ratio (OR) as the summary statistic for binary variables was used. Both a fixed and random effects model were applied. Subgroup analysis using quantitative methodology (risk of bias, metaregression) and graphical comparison (funnel plot) assessed statistical heterogeneity. Fourteen studies were selected. AOA with calcium ionophore increased the overall clinical pregnancy rate (per ET; OR = 3.48; 95% confidence interval [CI], 1.65-7.37) and the live birth rate (OR = 3.33; 95% CI, 1.50-7.39). This effect of adding calcium ionophore was further demonstrated with fertilization, cleavage, blastocyst, and implantation rates. Subgroup analysis further supported our findings (studies where n > 10 in both arms; random and fixed effects models). A metaregression (beta = -.145) found that as the quality of the study increases, the effect of calcium ionophore is significantly more pronounced with regards to overall pregnancy rate. AOA with calcium ionophore treatment after intracytoplasmic sperm injection (ICSI) results in a statistically significant improvement in fertilization, cleavage, blastulation, and implantation rates, as well as overall pregnancy and live-birth rates. The conclusion of this systematic review, demonstrating a strong effect of calcium ionophore use, is reassuring and promising, particularly for couples for whom ICSI alone yields poor fertilization rates. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  8. Successful pregnancy after SrCl2 oocyte activation in couples with repeated low fertilization rates following calcium ionophore treatment.

    Science.gov (United States)

    Kim, Jun-Woo; Kim, Sang-Don; Yang, Seong-Ho; Yoon, San-Hyun; Jung, Jae-Hoon; Lim, Jin-Ho

    2014-06-01

    This report describes a successful pregnancy and delivery following oocyte activation with strontium chloride (SrCl2) in couples with repeated complete fertilization failure or low fertilization rates even after calcium ionophore treatment. Eight infertile couples who showed complete fertilization failure or low fertilization rates after conventional intracytoplasmic sperm injection (ICSI) and calcium ionophore treatment. When the results of fertilization were not satisfactory in the cycles, the oocytes were artificially activated by SrCl2 for the next attempts. Oocyte activation with SrCl2 significantly increased the fertilization rates, when compared with conventional ICSI or calcium ionophore treatment (61.7% vs. 20.0% or 25.3%, respectively). There was significant increase in the proportions of good-quality cleaved embryos (50.0% vs. 0% or 12.5%, respectively). The rate of surplus embryos that developed to blastocyst stage increased in SrCl2-treated oocytes, when compared with that in ICSI with or without calcium ionophore treatment (25.7% vs. 0% or 9.1%, respectively). Five successful pregnancies were attained after oocyte activation with SrCl2, of which eight healthy children were born. Physical and mental development of the children were normal from birth to 60 months. These results suggest that SrCl2 in treatment should be considered as an effective method for artificial oocyte activation (AOA) to improve fertilization rates and embryo quality in cases with complete fertilization failure or low fertilization rates after calcium ionophore treatment.

  9. Release of eicosanoids from white blood cells, platelets, smooth muscle cells, and endothelial cells in response to endotoxin and A23187.

    Science.gov (United States)

    Bottoms, G D; Johnson, M; Ward, D; Fessler, J; Lamar, C; Turek, J

    1986-01-01

    Endotoxin produces numerous pathophysiologic changes in animals, including vascular endothelial cell damage and hematologic changes. Direct effects of endotoxin on arachidonic acid metabolism and the release of eicosanoids from endothelial cells and neutrophils have been reported. A rapid release of these autocoids occurs when cells are incubated with endotoxin, and this appears to be one of the earliest endotoxin-induced changes. Some of these eicosanoids may result in beneficial effects, and others may result in detrimental effects. This study was to determine the release of eicosanoids from white blood cells, platelets, smooth muscle cells, and endothelial cells in response to varying amounts of endotoxin and the calcium ionophore A23187. The results indicate that endotoxin has a major direct effect on vascular endothelial cells and smooth muscle cells as indicated by its ability to increase the synthesis of predominately i6-keto-PGF1 alpha by these cells. These effects were seen within a dose range of endotoxin that is lethal in horses. Very high concentrations of endotoxin (100 micrograms/ml) were required to stimulate a small increase in the production of i6-keto-PGF1 alpha and iLTC4 by freshly isolated neutrophils. Stimulation of cells with A23187 revealed that, of the eicosanoids measured, the one produced predominately by endothelial cells and smooth muscle cells was 6-keto-PGF1 alpha, by platelets was TxB2, and by neutrophils was LTC4 (LTB4 was not measured). A mixture of all white blood cells including platelets when incubated with A23187 produced large amounts of TxB2, LTB4, and LTC4 with smaller amounts of 6-keto-PGF1 alpha. The results indicate that endotoxin directly affects cells and stimulates them to produce thromboxane and prostacyclin, but very high concentrations of endotoxin were required to stimulate neutrophils to produce rather small increases in iLTC4.

  10. Studies on Calcium Ion Selectivity of ZnO Nanowire Sensors Using Ionophore Membrane Coatings

    Directory of Open Access Journals (Sweden)

    M. H. Asif

    2008-01-01

    Full Text Available Zinc oxide nanorods with 100 nm diameter and 900 nm length were grown on the surface of a silver wire (0.25 mm in diameter with the aim to produce electrochemical nanosensors. It is shown that the ZnO nanorods exhibit a Ca2+-dependent electrochemical potentiometric behavior in an aqueous solution. The potential difference was found to be linear over a large logarithmic concentration range (1 M to 0.1 M using Ag/AgCl as a reference electrode and the response time was less than one minute. In order to adapt the sensors for calcium ion measurements in biological fluids with sufficient selectivity and stability, plastic membrane coatings containing ionophores were applied. These functionalized ZnO nanorods sensors showed a high sensitivity (26.55 mV/decade and good stability.

  11. Successful pregnancy and childbirth after intracytoplasmic sperm injection with calcium ionophore oocyte activation in a globozoospermic patient.

    Science.gov (United States)

    Tejera, Alberto; Mollá, Marta; Muriel, Lourdes; Remohí, Jose; Pellicer, Antonio; De Pablo, Jose Luis

    2008-10-01

    To check the effectiveness of intracytoplasmic sperm injection (ICSI) combined with assisted oocyte activation (AOA) in a globozoospermic patient. Case report. Instituto Valenciano de Infertilidad, Valencia, Spain. A patient with globozoospermia. ICSI was administered in 14 oocytes. ICSI combined with AOA, in which a small amount of calcium was injected followed by calcium ionophore exposure, was done in 9 oocytes. Fertilization rate and embryo quality was assessed in both groups. Chemical activation increased fertilization rate (55.6% vs. 35.7%) and the number of embryos with less multinucleation on day 2 (0 vs. 60%). Two embryos generated from AOA were transferred into the uterus (on day 3), resulting in a pregnancy and a healthy newborn. The AOA with calcium ionophore treatment improved fertilization rate and quality of the embryos, and was found to be an effective method for AOA in this patient with a low fertilization rate after previous ICSI treatment.

  12. Role of Calcium Signaling in the Transcriptional Regulation of the Apicoplast Genome of Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Sabna Cheemadan

    2014-01-01

    Full Text Available Calcium is a universal second messenger that plays an important role in regulatory processes in eukaryotic cells. To understand calcium-dependent signaling in malaria parasites, we analyzed transcriptional responses of Plasmodium falciparum to two calcium ionophores (A23187 and ionomycin that cause redistribution of intracellular calcium within the cytoplasm. While ionomycin induced a specific transcriptional response defined by up- or downregulation of a narrow set of genes, A23187 caused a developmental arrest in the schizont stage. In addition, we observed a dramatic decrease of mRNA levels of the transcripts encoded by the apicoplast genome during the exposure of P. falciparum to both calcium ionophores. Neither of the ionophores caused any disruptions to the DNA replication or the overall apicoplast morphology. This suggests that the mRNA downregulation reflects direct inhibition of the apicoplast gene transcription. Next, we identify a nuclear encoded protein with a calcium binding domain (EF-hand that is localized to the apicoplast. Overexpression of this protein (termed PfACBP1 in P. falciparum cells mediates an increased resistance to the ionophores which suggests its role in calcium-dependent signaling within the apicoplast. Our data indicate that the P. falciparum apicoplast requires calcium-dependent signaling that involves a novel protein PfACBP1.

  13. Effect of sperm cryopreservation and treatment with calcium ionophore or heparin on in vitro fertilization of horse oocytes.

    Science.gov (United States)

    Alm, H; Torner, H; Blottner, S; Nürnberg, G; Kanitz, W

    2001-09-15

    Little information is available on methods of sperm capacitation for IVF in the horse. In this study, we summarized results of several independent trials that compared acrosome reaction, hyperactivation and chromatin integrity of fresh or cryopreserved stallion spermatozoa after treatment with heparin or with calcium ionophore. We also examined the influence of spermatozoa storage (fresh vs. cryopreserved), capacitation treatment, oocyte maturation time and cumulus morphology on the penetration rate and fertilization rate. We recovered cumulus-oocyte-complexes (COCs) from ovaries by ultrasound guided follicle aspiration or by scraping of follicles from ovaries obtained at a slaughterhouse. Upon recovery, we evaluated the cumulus morphology, and the COCs were matured in vitro for 18 to 24 or 26 to 40 h. Fresh semen and cryopreserved semen were treated either with heparin (200 microg/mL) or calcium ionophore (7.14 microM). Overall, 28.4% (99/349) of the oocytes were penetrated, and 12.9% (45/349) were fertilized. Fresh spermatozoa treated with calcium ionophore showed a higher penetration rate than cryopreserved spermatozoa (36.0 vs. 0%). Fresh and heparin-treated spermatozoa showed a penetration rate of 29.1%, and the same treatment for cryopreserved spermatozoa showed a penetration rate of 33.7%; none of these differences was significant (P>0.05). Fertilization rates after the calcium and heparin treatment followed the same trend and also showed no significant differences. Prolonged maturation period resulted in higher penetration (Pfertilization rates in compact (26 to 40 h: 37.7 and 13.1% vs. 18 to 24 h: 13.1 and 2.8%) and in tendency in expanded COCs (26 to 40 h: 40.0 and 30.3% vs. 18 to 24 h: 29.4 and 13.5%). In oocytes with only a few cumulus cells, the rates tended to be higher after the shorter incubation (18 to 24 h: 33.5 and 18.8% vs. 26 to 40 h: 17.2 and 6.5%). We observed hyperactivation more frequently in fresh than in cryopreserved semen after

  14. Successful pregnancy and delivery after ICSI with artificial oocyte activation by calcium ionophore in in-vitro matured oocytes: a case report.

    Science.gov (United States)

    Kim, Jun-Woo; Yang, Seong-Ho; Yoon, San-Hyun; Kim, Sang-Don; Jung, Jae-Hoon; Lim, Jin-Ho

    2015-04-01

    The achievement of a successful pregnancy and delivery after oocyte activation with calcium ionophore is reported in a couple having low fertilization rates after intracytoplasmic sperm injection (ICSI) of in-vitro matured oocytes. A couple, in which the wife had polycystic ovary syndrome and the husband had moderate oligoteratozoospermia, showed a low fertilization rate in a previous in-vitro maturation cycle (2/11 [18.2%]). The most likely cause of complete fertilization failure or low fertilization rates is failure of oocyte activation. Therefore, artificial oocyte activation by calcium ionophore was combined with ICSI to achieve viable fertilized oocytes. Oocytes were stimulated with calcium ionophore for 30 min after ICSI. The fertilization rate of oocytes activated with calcium ionophore (13/15 [86.7%] and 7/9 [77.8%]) was higher than that of the non-activated oocytes. In the latest cycle, three embryos derived from the activated oocytes were transferred into the uterus on day 3. Subsequently, two gestational sacs were identified on ultrasound. The patient delivered dizygotic twins (girl 2260 g and boy 2760 g) at 35 weeks and 6 days gestation by caesarean section. This result suggests that calcium ionophore could be useful for oocyte fertilization in couples with low fertilization rates after ICSI of in-vitro matured oocytes. Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  15. The dissociation of exocytosis and respiratory stimulation in leucocytes by ionophores.

    Science.gov (United States)

    Zabucchi, G; Romeo, D

    1976-01-01

    By exploiting the unique characteristics of three ionophores, experimental conditions were found which permit the dissociation of respiratory stimulation from secretion in polymorphonuclear leucocytes. A marked stimulation of respiration was produced by ionophore X537A, which binds and transports both alkali-earth and alkali cations. The stimulatory activity of this ionophore was the same at either high or low Na+/K+ ratios in the medium and was virtually unaffected by extracellular Ca2+. A slight stimulation of oxygen consumption was also caused by the K+-selective ionophore valinomycin and by ionophore A23187, which complexes and transfers bivalent cations. Ionophore X537A and valinomycin were unable to stimulate selective release of granuleassociated beta-glucuronidase and gradually increased cell fragility, as monitored by increased leakage of lactate dehydrogenase. Ionophore A23187 slightly increased exocytosis of beta-glucuronidase. In a Mg2+-free medium, Ca2+, added simultaneously with ionophore A23187, greatly enhanced respiration and secretion of the granule enzyme. If Ca2+ was added a few minutes after the ionophore, exocytosis occurred, but no respiratory burst was observed. If the latter experiment was repeated in the presence of extracellular Mg2+, both secretion and respiration were stimulated. This effect was not produced by Mn2+ or Ba2+. It is proposed that Ca2+ is required for triggering selective secretion of granule enzymes from leucocytes is caused by an intracellular redistribution of cations, which may invovle Mg2+-dependent mechanisms. PMID:782449

  16. Ca2+ uptake and cellular integrity in rat EDL muscle exposed to electrostimulation, electroporation, or A23187

    DEFF Research Database (Denmark)

    Gissel, Hanne; Clausen, Torben

    2003-01-01

    We tested the hypothesis that increased Ca2+ uptake in rat extensor digitorum longus (EDL) muscle elicits cell membrane damage as assessed from release of the intracellular enzyme lactate dehydrogenase (LDH). This was done by using 1) electrostimulation, 2) electroporation, and 3) the Ca2...... damage that arises during and after exercise or electrical shocks. Because membrane damage allows further influx of Ca2+, this results in positive feedback that may further increase membrane degeneration. Udgivelsesdato: 2003-Jul......+ ionophore A23187. Stimulation at 1 Hz for 120-240 min caused an increase in 45Ca uptake that was closely correlated to LDH release. This LDH release increased markedly with temperature. After 120 min of stimulation at 1 Hz, resting 45Ca uptake was increased 5.6-fold compared with unstimulated muscles...

  17. Application of a ready-to-use calcium ionophore increases rates of fertilization and pregnancy in severe male factor infertility.

    Science.gov (United States)

    Ebner, Thomas; Köster, Maria; Shebl, Omar; Moser, Marianne; Van der Ven, Hans; Tews, Gernot; Montag, Markus

    2012-12-01

    To analyze whether a ready-to-use calcium ionophore improves outcomes, from fertilization to live birth, in patients with severe male factor infertility. Artificial oocyte activation offered to applicable patients over a 20-month period. Specialized in vitro fertilization (IVF) centers in Austria and Germany. Twenty-nine azoospermic and 37 cryptozoospermic men. Mature oocytes treated with a ready-to-use Ca(2+)-ionophore (GM508 Cult-Active) immediately after intracytoplasmic sperm injection (ICSI). Rates of fertilization, implantation, clinical pregnancy, and live birth. Patients had had 88 previous cycles without artificial activation that resulted in a fertilization rate of 34.7%, 79 transfers (89.8%), and 5 pregnancies, which all spontaneously aborted except one. After artificial oocyte activation, the fertilization rate was 56.9%. In terms of fertilization rate, both azoospermic (64.4%) and cryptozoospermic (48.4%) men statistically significantly benefited from use of the ionophore. In 73 transfer cycles, positive β-human chorionic gonadotropin levels were observed in 34 cases (46.6%) and 29 cycles (39.7%) that ended with a clinical pregnancy. The corresponding implantation rate was 33.3%. Four spontaneous abortions occurred (11.8%), and 32 healthy children were born. This is the first prospective multicenter study on artificial oocyte activation in severe male factor infertility. Present data indicate that a ready-to-use calcium ionophore can yield high fertilization and pregnancy rates for this particular subgroup. In addition to fertilization failure after ICSI, severe male factor infertility is an additional area for application of artificial oocyte activation. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  18. Artificial oocyte activation with calcium ionophore allowed fertilization and pregnancy in a couple with long-term unexplained infertility where the female partner had diminished EGG reserve and failure to fertilize oocytes despite intracytoplasmic sperm injection.

    Science.gov (United States)

    Check, J H; Summers-Chase, D; Cohen, R; Brasile, D

    2010-01-01

    To determine if fertilization and embryo development and pregnancy was possible following in vitro fertilization (IVF) in a couple with long-term unexplained infertility where the female partner had diminished egg reserve and where fertilization failure occurred despite conventional oocyte insemination and intracyoplasmic sperm injection (ICSI). In vitro fertilization was performed using a low-dose follicle stimulating hormone (FSH) stimulation protocol. Prior to ICSI, artificial oocyte activation with calcium ionophore was used. Only one mature oocyte was retrieved but it fertilized and cleaved to a good quality 8-cell embryo on day 3. A pregnancy with fetal viability was achieved but she subsequently miscarried. A second attempt successful. Fertilization and pregnancy is possible even in women with diminished egg reserve with previous failed fertilization with ICSI by performing artificial oocyte activation with calcium ionophore. It is not clear if the sperm lacked oscillin or if the eggs were not responsive to oscillin.

  19. Ca2+ ionophores are not suitable for inducing mPTP opening in murine isolated adult cardiac myocytes.

    Science.gov (United States)

    Panel, Mathieu; Ghaleh, Bijan; Morin, Didier

    2017-06-27

    Opening of the mitochondrial permeability transition pore (mPTP) plays a major role in cell death during cardiac ischaemia-reperfusion. Adult isolated rodent cardiomyocytes are valuable cells to study the effect of drugs targeting mPTP. This study investigated whether the use of Ca2+ ionophores (A23187, ionomycin and ETH129) represent a reliable model to study inhibition of mPTP opening in cardiomyocytes. We monitored mPTP opening using the calcein/cobalt fluorescence technique in adult rat and wild type or cyclophilin D (CypD) knock-out mice cardiomyocytes. Cells were either treated with Ca2+ ionophores or subjected to hypoxia followed by reoxygenation. The ionophores induced mPTP-dependent swelling in isolated mitochondria. A23187, but not ionomycin, induced a decrease in calcein fluorescence. This loss could not be inhibited by CypD deletion and was explained by a direct interaction between A23187 and cobalt. ETH129 caused calcein loss, mitochondrial depolarization and cell death but CypD deletion did not alleviate these effects. In the hypoxia-reoxygenation model, CypD deletion delayed both mPTP opening and cell death occurring at the time of reoxygenation. Thus, Ca2+ ionophores are not suitable to induce CypD-dependent mPTP opening in adult murine cardiomyocytes. Hypoxia-reoxygenation conditions appear therefore as the most reliable model to investigate mPTP opening in these cells.

  20. Calcium-sensitive regulation of monoamine oxidase-A contributes to the production of peroxyradicals in hippocampal cultures: implications for Alzheimer disease-related pathology

    Directory of Open Access Journals (Sweden)

    Li XinMin

    2007-09-01

    Full Text Available Abstract Background Calcium (Ca2+ has recently been shown to selectively increase the activity of monoamine oxidase-A (MAO-A, a mitochondria-bound enzyme that generates peroxyradicals as a natural by-product of the deamination of neurotransmitters such as serotonin. It has also been suggested that increased intracellular free Ca2+ levels as well as MAO-A may be contributing to the oxidative stress associated with Alzheimer disease (AD. Results Incubation with Ca2+ selectively increases MAO-A enzymatic activity in protein extracts from mouse hippocampal HT-22 cell cultures. Treatment of HT-22 cultures with the Ca2+ ionophore A23187 also increases MAO-A activity, whereas overexpression of calbindin-D28K (CB-28K, a Ca2+-binding protein in brain that is greatly reduced in AD, decreases MAO-A activity. The effects of A23187 and CB-28K are both independent of any change in MAO-A protein or gene expression. The toxicity (via production of peroxyradicals and/or chromatin condensation associated with either A23187 or the AD-related β-amyloid peptide, which also increases free intracellular Ca2+, is attenuated by MAO-A inhibition in HT-22 cells as well as in primary hippocampal cultures. Conclusion These data suggest that increases in intracellular Ca2+ availability could contribute to a MAO-A-mediated mechanism with a role in AD-related oxidative stress.

  1. Effect of Ionophores on Activity of Na+,Cl-(HCO 3- )-ATPase.

    Science.gov (United States)

    Yurkiv, V A; Melikhov, V I; Shubin, V S

    2016-10-01

    We studied the effects of ionophores on activity of Na+,Cl-(HCO 3- )-ATPase. The most significant effect on the activity of this enzyme was produced by protonophore 2,4-dinitrophenol. The effect of this drug largely depended on the cation and anion composition and pH of the incubation medium and its pH. Activity of Na+,Cl-(HCO 3- )-ATPase increased at neutral and weakly alkaline pH and decreased at pH below 6.5-6.7. In control animals (without histamine injection) with very weak or absent Na+,Cl-(HCO 3- )-ATPase activity, the observed effect of the protonophore on ATPase activity was also virtually absent. The stimulatory effect of other ionophores (monensine, valinomycin, and A23187) was significantly weaker and depended on pH of the incubation medium, its cationic and anionic composition, and concentration of these ionophores.

  2. In vitro fertilization of in vitro-matured equine oocytes: effect of maturation medium, duration of maturation, and sperm calcium ionophore treatment, and comparison with rates of fertilization in vivo after oviductal transfer.

    Science.gov (United States)

    Hinrichs, K; Love, C C; Brinsko, S P; Choi, Y H; Varner, D D

    2002-07-01

    Three experiments were conducted to evaluate the effect of oocyte and sperm treatments on rates of in vitro fertilization (IVF) in the horse and to determine the capacity of in vitro-matured horse oocytes to be fertilized in vivo. There was no effect of duration of oocyte maturation (24 vs. 42 h) or calcium ionophore concentration during sperm capacitation (3 microM vs. 7.14 microM) on in vitro fertilization rates. Oocytes matured in 100% follicular fluid had significantly higher fertilization (13% to 24%) than did oocytes matured in maturation medium or in 20% follicular fluid (0% to 12%; P fertilization rate among 3 sperm treatments utilizing 7.14 microM calcium ionophore (12% to 21%). Of in vitro-matured oocytes recovered 40-44 h after transfer to the oviducts of inseminated mares, 77% showed normal fertilization (2 pronuclei to normal cleavage). Cleavage to 2 or more cells was seen in 22% of oocytes matured in follicular fluid and 63% of oocytes matured in maturation medium; this difference was significant (P horse oocytes are capable of being fertilized at high rates in the appropriate environment and that in vitro maturation of oocytes in follicular fluid increases fertilization rate in vitro but reduces embryo development after fertilization in vivo. Further work is needed to determine the optimum environment for sperm capacitation and IVF in the horse.

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

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, M.A.

    1985-01-01

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

  4. Electrochemical methods for the determination of the diffusion coefficient of ionophores and ionophore-ion complexes in plasticized PVC membranes.

    Science.gov (United States)

    Bodor, Sándor; Zook, Justin M; Lindner, Erno; Tóth, Klára; Gyurcsányi, Róbert E

    2008-05-01

    The diffusion coefficients of active components in ion-selective membranes have a decisive influence on the life-time and detection limit of the respective ion-selective electrodes, as well as influencing the rate of polarization and relaxation processes of electrically perturbed ion sensors. Therefore, the rational design of mass transport controlled ion-selective electrodes with sub-nanomolar detection limits requires reliable data on the diffusion coefficients. We have implemented electrochemical methods for the quantitative assessment of both the diffusion coefficients of free ionophores and ion-ionophore complexes. The diffusion coefficients of the pH-sensitive chromoionophore ETH 5294 and the calcium-selective ionophore ETH 5234 were determined in plasticized PVC membranes with different PVC to plasticizer ratios. The diffusion coefficient of the free chromoionophore determined by a chronoamperometric method was validated with optical methods for a variety of membrane compositions. The calcium-selective ionophore ETH 5234 was used as a model compound to assess the diffusion coefficient of the ion-ionophore complex calculated from the time required for the complexes to cross a freshly prepared membrane during potentiometric ion-breakthrough experiments. The difference between the diffusion coefficients of the free ionophore ETH 5234 and the ion-ionophore complex was found to be significant and correlated well with the geometry of the respective species.

  5. Ionophores in the Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Björklund, Erland

    production. Ionophores are antibiotic drugs that form lipid soluble complexes with, primarily, alkali cations that inhibit or kill pathogenic parasites in livestock. Several reports have revealed that ionophores are emerging environmental contaminants in agricultural run-off waters, surface waters, sediments...... liquid extraction with integrated clean-up followed by solid phase extraction and high-performance liquid chromatography tandem in space mass spectrometry (PLE-SPE-LC-MS/MS). Halling-Sørensen B, Sengelov G, Tjornelund J (2002) Arch Environ Contam Toxicol, 42: 3, p. 263-271. DOI: 10.1007/s00244...

  6. Regulation of xanthine oxidoreductase protein expression by hydrogen peroxide and calcium.

    Science.gov (United States)

    McNally, J Scott; Saxena, Archana; Cai, Hua; Dikalov, Sergey; Harrison, David G

    2005-08-01

    We have previously demonstrated that endothelial xanthine oxidase (XO) levels are dependent on the NADPH oxidase. We postulated that H2O2 may modulate the irreversible conversion of xanthine dehydrogenase (XDH) to XO and sought to examine mechanisms involved. H2O2 (100 micromol/L) decreased bovine aortic endothelial cell (BAEC) XDH protein expression, and metabolic labeling studies indicated that H2O2 stimulated conversion of XDH to XO. The decline in XDH was mimicked by the reactive oxygen species (ROS) generating compounds SIN-1 and Menadione, as well as by stimulating BAECs with angiotensin II (200 nmol/L). BAPTA-AM prevented the decline in XDH by H2O2, indicating that it was calcium-dependent. In keeping with calcium acting downstream of H2O2, the calcium ionophore A23187 (1 micromol/L) caused XDH-to-XO conversion, and this was not prevented by the antioxidants. In addition, XDH-to-XO conversion was blocked by 2-APB and NO donors and induced by thapsigargin and M-3M3FBS, implicating phospholipase C and endoplasmic reticulum calcium stores in this process. Endothelial XO and XDH expression are strongly dependent on H2O2 and calcium. Stimulation of XDH conversion to XO may represent a feed-forward mechanism whereby H2O2 can stimulate further production of ROS.

  7. Cyclic AMP-independent secretion of mucin by SW1116 human colon carcinoma cells. Differential control by Ca2+ ionophore A23187 and arachidonic acid

    National Research Council Canada - National Science Library

    Yedgar, S; Eidelman, O; Malden, E; Roberts, D; Etcheberrigaray, R; Goping, G; Fox, C; Pollard, H B

    1992-01-01

    The regulation of mucin secretion by SW1116 human colon carcinoma cells has been studied using monoclonal antibody 19-9, which has previously been used to detect mucin in the serum of cancer and cystic fibrosis patients...

  8. Synergistic fungicidal activities of polymyxin B and ionophores, and their dependence on direct disruptive action of polymyxin B on fungal vacuole.

    Science.gov (United States)

    Ogita, Akira; Konishi, Yukiko; Borjihan, Baiyinlang; Fujita, Ken-ichi; Tanaka, Toshio

    2009-02-01

    Polymyxin B (PMB) acts selectively on Gram-negative bacteria by electrostatic and hydrophobic interactions with anionic cell envelope components such as phospholipids and lipopolysaccharides. In this study, PMB was shown to exhibit marked fungicidal activity against yeasts and filamentous fungi in combination with ionophores such as salinomycin (SAM) and monensin (MON), which can selectively interact with monovalent cations. Ca(2+)-selective ionophores, A23187 and ionomycin, were absolutely ineffective in enhancing the fungicidal activity of PMB. SAM and MON increased the rate of cellular uptake of PMB possibly in favor of its intracellular action on the organelle. PMB could indeed directly disrupt the spherical membrane-enclosed architecture of the isolated vacuoles equally in the absence and presence of the ionophores. The loss of energy barrier for transmembrane transport of monovalent cations is considered to be a cause of enhanced incorporation of larger cationic compounds such as PMB across fungal plasma membrane.

  9. Abiotic degradation of antibiotic ionophores

    DEFF Research Database (Denmark)

    Bohn, Pernille; Bak, Søren A; Björklund, Erland

    2013-01-01

    Hydrolytic and photolytic degradation were investigated for the ionophore antibiotics lasalocid, monensin, salinomycin, and narasin. The hydrolysis study was carried out by dissolving the ionophores in solutions of pH 4, 7, and 9, followed by incubation at three temperatures of 6, 22, and 28 °C f...... because they absorb light of environmentally irrelevant wavelengths....

  10. A free calcium wave traverses the activating egg of the medaka, Oryzias latipes

    Energy Technology Data Exchange (ETDEWEB)

    Gilkey, J.C.; Jaffee, L.E.; Ridgway, E.B.; Reynolds, G.T.

    1978-02-01

    Aequorin injected eggs of the medaka (a fresh water fish) show an explosive rise in free calcium during fertilization, which is followed by a slow return to the resting level. Image intensification techniques now show a spreading wave of high free calcium during fertilization. The wave starts at the animal pole (where the sperm enters) and then traverses the egg as a shallow, roughly 20/sup 0/-wide band which vanishes at the antipode some minutes later. The peak free calcium concentration within this moving band is estimated to be about 30 ..mu..M (perhaps 100 to 1,000 times the resting level). Eggs activated by ionophore A23187 may show multiple initiation sites. The resulting multiple waves never spread throuh each other, rather, they fuse upon meeting so as to form spreading waves of compound origin. The fertilization wave is nearly independent of extracellular calcium because it is only slightly slowed (by perhaps 15%) in a medium containing 5mM ethylene glycol-bis(..beta..-aminoethyl ether)N,N'-tetraacetic acid (EGTA) and no deliberately added calcium. It is also independent of the large cortical vesicles, which may be centrifugally displaced. Normally, however, it distinctly precedes the well-known wave of cortical vesicle exocytosis. We conclude that the fertilization wave in the medaka egg is propagated by calcium-stimulated calcium release, primarily from some internal sources other than the large cortical vesicles. A comparison of the characteristics of the exocytotic wave in the medaka with that in other eggs, particularly in echinoderm eggs, suggests that such a propagated calcium wave is a general feature of egg activation.

  11. Anti-allergic inflammatory activity of the fruit of Prunus persica: role of calcium and NF-kappaB.

    Science.gov (United States)

    Shin, Tae-Yong; Park, Seung-Bin; Yoo, Jin-Su; Kim, In Kyeom; Lee, Hyun-Shik; Kwon, Taeg Kyu; Kim, Moon Kyu; Kim, Jung Chul; Kim, Sang-Hyun

    2010-10-01

    Mast cell-mediated allergic symptoms are involved in many diseases, such as asthma and sinusitis. In this study, we investigated the effect of ethanol extract of fruits of Prunus persica (L) Batsch (FPP) on the mast cell-mediated allergic inflammation and studied the possible mechanism of action. FPP dose-dependently inhibited compound 48/80-induced systemic anaphylaxis and immunoglobulin E-mediated local allergic reactions. Histamine releasing from mast cells was reduced by FPP, which was mediated by modulation of intracellular calcium. In addition, FPP attenuated the phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-stimulated expression and secretion of pro-inflammatory cytokines in human mast cells. The inhibitory effect of FPP on pro-inflammatory cytokines was nuclear factor (NF)-kappaB dependent. Our findings provide evidence that FPP inhibits mast cell-derived allergic inflammation and involvement of calcium and NF-kappaB in these effects. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  12. Suppression or induction of apoptosis by opposing pathways downstream from calcium-activated calcineurin

    OpenAIRE

    Lotem, Joseph; Kama, Rachel; Sachs, Leo

    1999-01-01

    Ca2+-mobilizing compounds such as the Ca2+ ionophore A23187 or the endoplasmic reticulum Ca2+ ATPase inhibitor thapsigargin can suppress or induce apoptosis in the same cells. The use of different calcineurin inhibitors has shown that both suppression and induction of apoptosis by the Ca2+-mobilizing compounds were mediated by calcineurin activation. Ca2+-mobilizing compounds activated p38 and p44/42 mitogen-activated protein kinases (MAPKs). Induction of apoptosis by the Ca2+-mobilizing comp...

  13. A self-assembled ionophore

    Science.gov (United States)

    Tirumala, Sampath K.

    1997-11-01

    Ionophores are compounds that bind and transport ions. Ion binding and transport are fundamental to many biological and chemical processes. In this thesis we detail the structural characterization and cation binding properties of a self-assembled ionophore built from an isoguanosine (isoG) derivative, 5sp'-t-butyldimethylsilyl-2sp',3sp'-isopropylidene isoG 30. We begin with a summary of the themes that facilitate ionophore design and the definitions of "self-assembly" and "self-assembled ionophore" in Chapter 1. In Chapter 2, we describe the structural characterization of the isoG 30 self-assembly. IsoG possesses complementary hydrogen bond donor and acceptor sites suitable to form a Csb4-symmetric tetramer, (isoG)sb4 51, that is stable even in high dielectric organic solvents such as CDsb3CN and dsb6-acetone. The isoG tetramer 51 has been characterized by vapor phase osmometry, UV spectroscopy, and by 1D and 2D NMR spectroscopy. The isoG tetramer 51 organizes by hydrogen bonding between the Watson-Crick face of one isoG base and the complementary bottom edge of another purine. The tetramer 51 is stabilized by an inner and outer ring of hydrogen bonds. The inner ring forms between the imino NH1 proton of one monomer and the C2 carbonyl oxygen of an adjacent monomer, while the outer ring is made up of four NH6-N3 hydrogen bonds. The isoG tetramer 51 is thermodynamically stable, with an equilibrium constant (Ksba) of ca. 10sp9-10sp{10} Msp{-3} at room temperature, and a DeltaGsp° of tetramer formation of -12.5 kcal molsp{-1} in dsb6-acetone at 25sp°C. The van't Hoff plots indicated that the thermodynamic parameters for tetramer formation were DeltaHsp° = -18.2 ± 0.87 kcal molsp{-1} and DeltaSsp°sb{298} = -19.1 ± 5.45 eu. In Chapter 3, we describe the cation binding properties of isoG tetramer 51. The isoG tetramer 51 has a central cavity, containing four oxygen atoms, that is suitable for cation coordination. Depending on the cation, the resulting iso

  14. Abiotic degradation of antibiotic ionophores.

    Science.gov (United States)

    Bohn, Pernille; Bak, Søren A; Björklund, Erland; Krogh, Kristine A; Hansen, Martin

    2013-11-01

    Hydrolytic and photolytic degradation were investigated for the ionophore antibiotics lasalocid, monensin, salinomycin, and narasin. The hydrolysis study was carried out by dissolving the ionophores in solutions of pH 4, 7, and 9, followed by incubation at three temperatures of 6, 22, and 28 °C for maximum 34 days. Using LC-MS/MS for chemical analysis, lasalocid was not found to hydrolyse in any of the tested environments. Monensin, salinomycin, and narasin were all stable in neutral or alkaline solution but hydrolysed in the solution with a pH of 4. Half-lives at 25 °C were calculated to be 13, 0.6, and 0.7 days for monensin, salinomycin, and narasin, respectively. Absorbance spectra from each compound indicated that only lasalocid is degraded by photolysis (half-life below 1 h) due to an absorbance maximum around 303 nm, and monensin, salinomycin, and narasin are resistant to direct photolysis because they absorb light of environmentally irrelevant wavelengths. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Role of calcium in gonadotropin releasing hormone-induced luteinizing hormone secretion from the bovine pituitary

    Energy Technology Data Exchange (ETDEWEB)

    Kile, J.P.

    1986-01-01

    The hypothesis was tested that GnRH acts to release LH by increasing calcium uptake by gonadotroph which in turn stimulates calcium-calmodulin activity and results in LH release from bovine pituitary cells as it does in the rat. Pituitary glands of calves (4-10 months of age) were enzymatically dispersed (0.2% collagenase) and grown for 5 days to confluency in multiwell plates (3 x 10/sup 5//well). Cells treated with GnRH Ca/sup + +/ ionophore A23187, and ouabain all produced significant releases of LH release in a pronounced all or none fashion, while thorough washing of the cells with 0.5 mM EGTA in Ca/sup + +/-free media prevented the action of GnRH. GnRH caused a rapid efflux of /sup 45/Ca/sup + +/. Both GnRH-stimulated /sup 45/Ca efflux and LH release could be partially blocked by verapamil GnRH-induced LH release could also be blocked by nifedipine and tetrodotoxin, although these agents did not affect /sup 45/Ca efflux. The calmodulin antagonists calmidazolium and W7 were found to block GnRH induced LH release, as well as LH release induced by theophylline, KC PGE/sub 2/ and estradiol. These data indicated that: (1) calcium is required for GnRH action, but extracellular Ca/sup + +/ does not regulate LH release; (2) GnRH elevates intracellular Ca/sup + +/ by opening both voltage sensitive and receptor mediated Ca/sup + +/ channels; (3) activation of calmodulin is one mechanism involved in GnRH-induced LH release.

  16. Calcium

    Science.gov (United States)

    ... Turn to calcium-fortified (or "calcium-set") tofu, soy milk, tempeh, soy yogurt, and cooked soybeans (edamame). Calcium-fortified foods. Look for calcium-fortified orange juice, soy or rice milk, breads, and cereal. Beans. You can get decent ...

  17. Ca2+ ionophores trigger membrane remodeling without a need for store-operated Ca2+ entry.

    Science.gov (United States)

    Galitzine, Marie; Capiod, Thierry; Le Deist, Françoise; Meyer, Dominique; Freyssinet, Jean-Marie; Kerbiriou-Nabias, Danièle

    2005-02-04

    Calcium (Ca2+) ionophores are the most effective agents able to elicit rapid membrane remodeling in vitro. This process exposes aminophospholipids at the surface of platelets and blood cells, thus providing a catalytic surface for coagulation. To explore the underlying mechanism, we examined if cytosolic Ca2+ ([Ca2+]i) increase through store-operated Ca2+ entry (SOCE) was necessary for the potent effect of ionophores. Recent studies have demonstrated that the Ca2+-ATPase inhibitor thapsigargin, although able to elevate [Ca2+]i through SOCE, does not trigger the rapid membrane remodeling. However, it was not known if the additional effect of ionophores to promote the process required SOCE or could it occur independently. We took advantage of two mutant B lymphoblast cell lines, characterized either by defective SOCE or altered membrane remodeling, to simultaneously assess [Ca2+]i increase and membrane remodeling in the presence of ionophores or thapsigargin. Results imply that ionophores trigger membrane remodeling without the requirement for a functional SOCE.

  18. Age-related decline in activation of calcium/calmodulin-dependent phosphatase calcineurin and kinase CaMK-IV in rat T cells.

    Science.gov (United States)

    Pahlavani, M A; Vargas, D M

    1999-12-07

    We have previously shown that the DNA binding activity of the transcription factor NFAT which plays a predominant role in IL-2 transcription decreases with age. Because the transactivation (dephosphorylation and nuclear translocation) of the NFAT-c (cytoplasmic component of the NFAT complex) is mediated by the calcium/calmodulin-dependent phosphatase, calcineurin (CaN), and because Ca2+/calmodulin-dependent kinases (CaMK-II and IV/Gr) have been shown to play a critical role in calcium signaling in T cells, it was of interest to determine what effect aging has on the activation and the levels of these calcium regulating enzymes. The induction of calcineurin phosphatase activity, and CaMK-II and IV/Gr activities, were studied in splenic T cells isolated from Fischer 344 rats at 6, 15, and 24 months of age. In addition, the changes in the protein levels of these enzymes were measured by Western blot. The calcineurin phosphatase activity and CaMK-II and IV kinase activities were at a maximum after the cells were incubated with anti-CD3 antibody for 5-10 minutes. The induction of calcineurin activity by anti-CD3 and by calcium ionophore (A23187) declined 65 and 55%, respectively, between 6 and 24 months of age. The induction of CaMK-IV activity, but not CaMK-II activity by anti-CD3, was significantly less (by 54%) in T cells from old rats compared to T cells from young rats. The decline in the activation of these enzymes with age was not associated with changes in their corresponding protein levels. These results demonstrate that alterations in calcineurin phosphatase activity and CaMK-IV activity may contribute to the well-documented age-related decline in T cell function.

  19. Toxoplasma gondii: Induction of egress by the potassium ionophore nigericin

    Science.gov (United States)

    Fruth, Ingrid A.; Arrizabalaga, Gustavo

    2007-01-01

    The obligate intracellular parasite Toxoplasma gondii is an important pathogen of humans and animals. Some of the devastating consequences of toxoplasmosis are in part due to the lysis of the host cell during parasite egress. The process of egress is poorly understood and since it is asynchronous in tissue culture its study has been limited to those conditions that induce it, such as artificial permeabilization of the host cell and induction of calcium fluxes with ionophores. Given that permeabilization leads to egress by the activation of motility upon a drop in host cell potassium concentration, we investigated whether the ionophore nigericin, which selectively causes efflux of potassium from the cell without the need for permeabilization, would cause egress. Nigericin effectively causes intracellular parasites to exit their host cell within 30 min of treatment with the drug. Our results show that nigericin-induced egress depends on an efflux of potassium from the cell and requires phospholipase C function and parasite motility. This novel method of inducing and synchronizing egress mimics the effect of artificial permeabilization in all respects. Nevertheless, since the membrane remains intact during the treatment, in our nigericin-induced egress we are able to detect parasite-dependent permeabilization of the host cell, a known step in induced egress. In addition, consistent with the model that loss of host cell potassium leads to egress through the activation of intraparasitic calcium fluxes, a previously isolated Toxoplasma mutant lacking a sodium hydrogen exchanger and defective in responding to calcium fluxes does not undergo nigericin-induced egress. Thus, the discovery that nigericin induces egress presents a novel assay that allows for the genetic and biochemical analysis of the signaling mechanisms that lead to the induction of motility and egress. PMID:17618633

  20. Multiple cellular roles of Neurospora crassa plc-1, splA2, and cpe-1 in regulation of cytosolic free calcium, carotenoid accumulation, stress responses, and acquisition of thermotolerance.

    Science.gov (United States)

    Barman, Ananya; Tamuli, Ranjan

    2015-04-01

    Phospholipase C1 (PLC1), secretory phospholipase A2 (sPLA2) and Ca(2+)/H(+) exchanger proteins regulate calcium signaling and homeostasis in eukaryotes. In this study, we investigate functions for phospholipase C1 (plc-1), sPLA2 (splA2) and a Ca(2+)/H(+) exchanger (cpe-1) in the filamentous fungus Neurospora crassa. The Δplc-1, ΔsplA2, and Δcpe-1 mutants exhibited a growth defect on medium supplemented with the divalent ionophore A23187, suggesting that these genes might play a role in regulation of cytosolic free Ca(2+) concentration ([Ca(2+)](c)) in N. crassa. The strains lacking plc-1, splA2, and cpe-1 possessed higher carotenoid content than wild type at 8°C, 22°C, and 30°C, and showed increased ultraviolet (UV)-survival under conditions that induced carotenoid accumulation. Moreover, Δplc-1, ΔsplA2, and Δcpe-1 mutants showed reduced survival rate under hydrogen peroxide-induced oxidative stress and induced thermotolerance after exposure to heat shock temperatures. Thus, this study revealed multiple cellular roles for plc-1, splA2, and cpe-1 genes in regulation of [Ca(2+)](c), carotenoid accumulation, survival under stress conditions, and acquisition of thermotolerance induced by heat shock.

  1. Analytical strategies for assessing ionophores in the environment

    DEFF Research Database (Denmark)

    Hansen, Martin; Bjørklund, E.; Krogh, K A

    2009-01-01

    Ionophores are antiparasitic compounds used worldwide as prophylactic chemotherapeutics and growth promoters in livestock production. Several reports have revealed that ionophores are emerging environmental contaminants occurring in the environment in ...

  2. Calcium

    Science.gov (United States)

    ... and blood vessels contract and expand, to secrete hormones and enzymes and to send messages through the nervous system. It is important to get plenty of calcium in the foods you eat. Foods rich in calcium include Dairy products such as milk, cheese, and yogurt Leafy, green vegetables Fish with ...

  3. Mechanisms of hop inhibition: hop ionophores.

    Science.gov (United States)

    Behr, Jürgen; Vogel, Rudi F

    2009-07-22

    In this work, the mechanism of hop inhibition toward (beer spoiling) bacteria is revised. The mode of action of iso-alpha-acids was investigated via bilayer lipid membrane (BLM) measurements and growth challenges of hop-sensitive and -resistant Lactobacillus brevis strains in the presence of uncouplers of class I and II or a H(+)/Mn(2+) exchanger. The antibacterial action of iso-alpha-acids as proton ionophores could be confirmed by the BLM measurements; however, the reported ionophore properties, as electroneutral H(+)/Mn(2+) exchangers, could not be verified. Potentiometric measurements indicated the manganese-dependent enhancement of transmembrane charge permeation. The origin of high membrane potentials in the presence of manganese, as well as the strongly elevated membrane conductivity with concomitant increase in effectiveness of an uncoupler, suggest a different origin of charge transfer under these conditions. The mode of antibacterial action of hop ionophores can be described as proton ionophores of class I/II, which are capable transporting protons within a wide range of pH due to their inherent complexity of chemical composition. However, growth challenges in the presence of both types of ionophore classes in combination with the measured unusual high BLM potentials in the presence of manganese and at low pH indicate an additional mechanism of inhibition by hop compounds. The latter may be due to the nature/properties of hop compounds, which are known to be highly reactive substances. As a consequence, hop resistance of bacteria can be described as multiple resistance to a heterogeneous mixture of compounds comprising different known and yet unknown charge transport mechanisms, which were dependent on several factors, for example, compound concentrations, cation composition, and pH value. Thus, only specialists such as some L. brevis strains, which can cope with unusually low intracellular manganese levels, can survive hop stress. Accordingly, cross

  4. 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.

  5. Thin layer coulometry with ionophore based ion-selective membranes.

    Science.gov (United States)

    Grygolowicz-Pawlak, Ewa; Bakker, Eric

    2010-06-01

    We are demonstrating here for the first time a thin layer coulometric detection mode for ionophore based liquid ion-selective membranes. Coulometry promises to achieve the design of robust, calibration free sensors that are especially attractive for applications where recalibration in situ is difficult or undesirable. This readout principle is here achieved with porous polypropylene tubing doped with the membrane material and which contains a chlorinated silver wire in the inner compartment, together with the fluidically delivered sample solution. The membrane material consists of the lipophilic plasticizer dodecyl 2-nitrophenyl ether, the lipophilic electrolyte ETH 500, and the calcium ionophore ETH 5234. Importantly and in contrast to earlier work on voltammetric liquid membrane electrodes, the membrane also contains a cation-exchanger salt, KTFPB. This renders the membrane permselective and allows one to observe open circuit potentiometric responses for the device, which is confirmed to follow the expected Nernstian equation. Moreover, as the same cationic species is now potential determining at both interfaces of the membrane, it is possible to use rapidly diffusing and/or thin membrane systems where transport processes at the inner and outer interface of the membrane do not perturb each other or the overall composition of the membrane. The tubing is immersed in an electrolyte solution where the counter and working electrode are placed, and the potentials are applied relative to the measured open circuit potentials. Exhaustive current decays are observed in the range of 10 to 100 muM calcium chloride. The observed charge, calculated as integrated currents, is linearly dependent on concentration and forms the basis for the coulometric readout of ion-selective membrane electrodes.

  6. Calcium

    Science.gov (United States)

    ... from dietary supplements are linked to a greater risk of kidney stones, especially among older adults. But calcium from foods does not appear to cause kidney stones. For most people, other factors (such as not drinking enough fluids) probably have ...

  7. Extracting iron and manganese from bacteria with ionophores - a mechanism against competitors characterized by increased potency in environments low in micronutrients.

    Science.gov (United States)

    Raatschen, Nadja; Wenzel, Michaela; Ole Leichert, Lars Ingo; Düchting, Petra; Krämer, Ute; Bandow, Julia Elisabeth

    2013-04-01

    To maintain their metal ion homeostasis, bacteria critically depend on membrane integrity and controlled ion translocation. Terrestrial Streptomyces species undermine the function of the cytoplasmic membrane as diffusion barrier for metal cations in competitors using ionophores. Although the properties of the divalent cation ionophores calcimycin and ionomycin have been characterized to some extent in vitro, their effects on bacterial ion homeostasis, the factors leading to bacterial cell death, and their ecological role are poorly understood. To gain insight into their antibacterial mechanism, we determined the metal ion composition of the soil bacterium Bacillus subtilis after treatment with calcimycin and ionomycin. Within 15 min the cells lost approximately half of their cellular iron and manganese content whereas calcium levels increased. The proteomic response of B. subtilis provided evidence that disturbance of metal cation homeostasis is accompanied by intracellular oxidative stress, which was confirmed with a ROS-specific fluorescent probe. B. subtilis showed enhanced sensitivity to the ionophores in medium lacking iron or manganese. Furthermore, in the presence of ionophores bacteria were sensitive to high calcium levels. These findings suggest that divalent cation ionophores are particularly effective against competing microorganisms in soils rich in available calcium and low in available iron and manganese. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis.

    Science.gov (United States)

    Szkudlarek-Mikho, Maria; Saunders, Rudel A; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

    2012-11-30

    The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor γ. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Szkudlarek-Mikho, Maria; Saunders, Rudel A. [Department of Medicine, Biochemistry and Cancer Biology, Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH 43614 (United States); Yap, Sook Fan [Faculty of Medicine and Health Sciences, Department of Pre-Clinical Sciences, University of Tunku Abdul Rahman (Malaysia); Ngeow, Yun Fong [Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chin, Khew-Voon, E-mail: khew-voon.chin@utoledo.edu [Department of Medicine, Biochemistry and Cancer Biology, Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Toledo, OH 43614 (United States)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Salinomycin inhibits preadipocyte differentiation into adipocytes. Black-Right-Pointing-Pointer Salinomycin inhibits transcriptional regulation of adipogenesis. Black-Right-Pointing-Pointer Pharmacological effects of salinomycin suggest toxicity in cancer therapy. -- Abstract: The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor {gamma}. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy.

  10. ionophore supplementation on the performance of weaner wethers

    African Journals Online (AJOL)

    1999-02-08

    Feb 8, 1999 ... Subsequent trials have shown a decreased methane and lactic ... The response of sheep to ionophores in the feedlot situation is well established (Foreyt et a1.,. 1979), but the benefits of ... sheep to ionophores and the effect of zeranol on sheep performance are limited and do not exist for. South African ...

  11. Occurrence of Ionophores in the Danish Environment

    Directory of Open Access Journals (Sweden)

    Søren Alex Bak

    2014-11-01

    Full Text Available Antibiotics in the environment are a potential threat to environmental ecosystems as well as human health and safety. Antibiotics are designed to have a biological effect at low doses, and the low levels detected in the environment have turned focus on the need for more research on environmental occurrence and fate, to assess the risk and requirement for future regulation. This article describes the first occurrence study of the antibiotic polyether ionophores (lasalocid, monensin, narasin, and salinomycin in the Danish environment. Various environmental matrices (river water, sediment, and soil have been evaluated during two different sampling campaigns carried out in July 2011 and October 2012 in an agricultural area of Zealand, Denmark. Lasalocid was not detected in any of the samples. Monensin was measured at a concentration up to 20 ng·L−1 in river water and 13 µg·kg−1 dry weight in the sediment as well as being the most frequently detected ionophore in the soil samples with concentrations up to 8 µg·kg−1 dry weight. Narasin was measured in sediment samples at 2 µg·kg−1 dry weight and in soil between 1 and 18 µg·kg−1 dry weight. Salinomycin was detected in a single soil sample at a concentration of 30 µg·kg−1 dry weight.

  12. Characterization of Anthraquinone-DerivedRedox Switchable Ionophores and Their Complexes with Li+, Na+, K+, Ca+, and Mg+ Metal Ions

    Directory of Open Access Journals (Sweden)

    Vaishali Vyas

    2011-01-01

    Full Text Available Anthraquinone derived redox switchable ionophores 1,5 bis (2-(2-(2-ethoxy ethoxy ethoxyanthracene-9,10-dione (V1 and 1,8-bis(2-(2-(2-ethoxyethoxyethoxy anthracene—9,10-dione (V2 have been used for isolation, extraction and liquid membrane transport studies of Li+, Na+, K+, Ca2+ and Mg2+ metal ions. These isolated complexes were characterized by melting point determination, CV and IR, 1H NMR spectral analysis. Ionophore V2 shows maximum shift in reduction potential (ΔE with Ca(Pic2. The observed sequence for the shifting in reduction potential (ΔE between V2 and their complexes is V2 calcium picrate (42 mV > V2 potassium picrate (33 mV > V2 lithium picrate (25 mV > V2 sodium picrate (18 mV > V2 magnesium picrate (15 mV. These findings are also supported by results of extraction, back extraction and transport studies. Ionophore V2 complexed with KPic and showed much higher extractability and selectivity towards K+ than V1. These synthetic ionophores show positive and negative cooperativity towards alkali and alkaline earth metal ions in reduced and oxidized state. Hence, this property can be used in selective separation and enrichment of metal ions using electrochemically driven ion transport.

  13. Calcium has a permissive role in interleukin-1beta-induced c-jun N-terminal kinase activation in insulin-secreting cells

    DEFF Research Database (Denmark)

    Størling, Joachim; Zaitsev, Sergei V; Kapelioukh, Iouri L

    2005-01-01

    The c-jun N-terminal kinase (JNK) signaling pathway mediates IL-1beta-induced apoptosis in insulin-secreting cells, a mechanism relevant to the destruction of pancreatic beta-cells in type 1 and 2 diabetes. However, the mechanisms that contribute to IL-1beta activation of JNK in beta-cells are la......+) ionophore A23187, or exposure to thapsigargin, an inhibitor of sarco(endo)plasmic reticulum Ca(2+) ATPase, all caused an amplification of IL-1beta-induced JNK activation in INS-1 cells. Finally, a chelator of intracellular free Ca(2+) [bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid...

  14. Differential inhibitory effects of 2-azafluorenones on PI-PLC activation but not on PC-PLC- or PC-PLD-activation induced by histamine, PAF, PMA or A23187 in C6 glioma cells.

    Science.gov (United States)

    Wang, Hai-Long; Wang, Li-Chuan; Wei, Jiann-Wu

    2013-02-28

    In this study, C6 glioma cells were used to test the effects of 2-azafluorenone and its related compounds on membrane phosphatidylinositol (PI) and phosphatidylcholine (PC) turnover. An increase of [³H]-labeled inositol phosphate (IP1) formation by histamine (100 μM) or A23187 (100 nM) via the activation of phosphatidylinositol-specific phospholipase C (PI-PLC) to breakdown labeled substrate was observed, and this effect could be partially blocked by about half at 100 μM of 2-azafluorenones. Histamine induced the increase of IP1 formation, but failed to cause an increase in extracellularly releasing of [3H]choline metabolites, or intracellular accumulation of [³H]phosphscholine. However, platelet activation factor (PAF) from 0.2 to 1 μM, and phorbol 12-myristate-13-acetate (PMA) at 1 μM caused an increase in extracellularly releasing of [³H]choline metabolites, and intracellular accumulation of [³H]phosphocholine via the activation on phosphatidylcholine (PC)-PLC. These responses of PAF and PMA were not affected by 2-azafluorenone or 4-methyl-2-azafluorenone even at high concentration (10⁻⁴ M). A23187 induced an increase of intracellular [³H]choline release via the activation of PCphospholipase D (PLD). This increasing effect of 100 nM A23187 was not affected by 2-azafluorenone or 4-methyl-2-azafluorenone even at a high concentration of 10⁻⁴ M. In summary, the inhibitory effect of 2-azafluorenone and its related compound 4-methyl-2-azafluorenone was observed selectively on PIPLC, but not on PC-PLC or PC-PLD based on changes of products after the activation of these enzymes.

  15. Ionophore-based ion-selective optical nanosensors operating in exhaustive sensing mode.

    Science.gov (United States)

    Xie, Xiaojiang; Zhai, Jingying; Crespo, Gastón A; Bakker, Eric

    2014-09-02

    Ion selective optical sensors are typically interrogated under conditions where the sample concentration is not altered during measurement. We describe here an alternative exhaustive detection mode for ion selective optical sensors. This exhaustive sensor concept is demonstrated with ionophore-based nanooptodes either selective for calcium or the polycationic heparin antidote protamine. In agreement with a theoretical treatment presented here, linear calibration curves were obtained in the exhaustive detection mode instead of the sigmoidal curves for equilibrium-based sensors. The response range can be tuned by adjusting the nanosensor loading. The nanosensors showed average diameters of below 100 nm and the sensor response was found to be dramatically faster than that for film-based optodes. Due to the strong binding affinity of the exhaustive nanosensors, total calcium concentration in human blood plasma was successfully determined. Optical determination of protamine in human blood plasma using the exhaustive nanosensors was attempted, but was found to be less successful.

  16. Platinum porphyrins as ionophores in polymeric membrane electrodes

    DEFF Research Database (Denmark)

    Lvova, Larisa; Verrelli, Giorgio; Nardis, Sara

    2011-01-01

    A comparative study of Pt(II)- and Pt(IV)-porphyrins as novel ionophores for anion-selective polymeric membrane electrodes is performed. Polymeric membranes of different compositions, prepared by varying plasticizers, cationic and anionic additives and Pt porphyrins, have been examined by potenti......A comparative study of Pt(II)- and Pt(IV)-porphyrins as novel ionophores for anion-selective polymeric membrane electrodes is performed. Polymeric membranes of different compositions, prepared by varying plasticizers, cationic and anionic additives and Pt porphyrins, have been examined...... within the electrode membranes, while those based on Pt(IV)TPPCl2 operate via a mixed mode carrier mechanism, evidencing also a partial reduction of the starting ionophore to Pt(II)TPP. Spectrophotometric measurements of thin polymeric films indicate that no spontaneous formation of hydroxide ion bridged...... correlation between calculated and measured ionophore selectivity....

  17. Uranyl salophenes as ionophores for phosphate-selective electrodes

    NARCIS (Netherlands)

    Wroblewski, Wojciech; Wojciechowski, Kamil; Dybko, Artur; Brzozka, Zbigniew; Egberink, Richard J.M.; Ruel, Bianca H.M.; Reinhoudt, David

    2000-01-01

    Anion selectivities of poly(vinylchloride) (PVC) plasticized membranes containing uranyl salophene derivatives were presented. The influence of the membrane components (i.e. ionophore structure, dielectric constant and structure of plasticizer, the amount of incorporated ammonium salt) on its

  18. Polyether ionophores-promising bioactive molecules for cancer therapy.

    Science.gov (United States)

    Huczyński, Adam

    2012-12-01

    The natural polyether ionophore antibiotics might be important chemotherapeutic agents for the treatment of cancer. In this article, the pharmacology and anticancer activity of the polyether ionophores undergoing pre-clinical evaluation are reviewed. Most of polyether ionophores have shown potent activity against the proliferation of various cancer cells, including those that display multidrug resistance (MDR) and cancer stem cells (CSC). The mechanism underlying the anticancer activity of ionophore agents can be related to their ability to form complexes with metal cations and transport them across cellular and subcellular membranes. Increasing evidence shows that the anticancer activity of polyether ionophores may be a consequence of the induction of apoptosis leading to apoptotic cell death, arresting cell cycle progression, induction of the cell oxidative stress, loss of mitochondrial membrane potential, reversion of MDR, synergistic anticancer effect with other anticancer drugs, etc. Continued investigation of the mechanisms of action and development of new polyether ionophores and their derivatives may provide more effective therapeutic drugs for cancer treatments. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Extraction and detection of Ionophores in the Aquatic Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen

    Anticoccidial agents or coccidiostatics are the only anti-bacterial substances still authorised as feed additives within the European Union (Vincent et al. 2011). Anticoccidial agents are used for the prevention of the disease coccidiosis, which is caused by a unicellular intestinal parasite....... Coccidiosis is a major disease in poultry as well as in many other hosts. Ionophores are the most heavily applied sup-group of the two sub-groups of anticoccidial agents, because they also have antibacterial properties. After the ban of antibiotic growth promoters Ionophores are used extensively worldwide...... with resistance in the treatment of coccidiosis. Several reports have revealed that ionophores are emerging environmental contaminants in agricultural run-off waters, surface waters, sediments, and ground waters, due to their continuously increased and constant application as feed additives in modern livestock...

  20. Metal ionophores - an emerging class of anticancer drugs.

    Science.gov (United States)

    Ding, Wei-Qun; Lind, Stuart E

    2009-11-01

    Compounds that bind metals such as copper and zinc have many biological activities, including the ability to induce apoptosis in cancer cells. Although some of these compounds have been considered to act as chelators of metals, decreasing their bioavailability, others increase intracellular metal concentrations. We review recent work regarding the recognition of the biological effects of metal ionophores with different structures, particularly with regard to their actions upon cancer cells focusing on dithiocarbamates, pyrithione, and the 8-hydroxyquinoline derivative, clioquinol. We provide a biologically based classification of metal-binding compounds that allows an experimental distinction between chelators and ionophores that can be readily used by biologists, which may lead to further study and classification of metal-binding drugs. Metal ionophores may kill cancer cells by a number of mechanisms, including lysosomal disruption and proteasome inhibition, and likely others. Because some of these compounds have been safely administered to animals and humans, they have the potential to become clinically useful anticancer agents.

  1. Inhibition of basophil histamine release by gangliosides. Further studies on the significance of cell membrane sialic acid in the histamine release process

    DEFF Research Database (Denmark)

    Jensen, C; Norn, S; Thastrup, Ole

    1987-01-01

    Histamine release from human basophils was inhibited by preincubation of the cells with a glucolipid mixture containing sialic acid-containing gangliosides. This was true for histamine release induced by anti-IgE, Concanavalin A and the calcium ionophore A23187, whereas the release induced by S. ...

  2. Characterization of glutamate-induced formation of N- acylphosphatidylethanolamine and N-acylethanolamine in cultured neocortical neurons

    DEFF Research Database (Denmark)

    Hansen, Harald S.; Lauritzen, L.; Strand, A.M.

    1997-01-01

    -induced formation was seen in 2-day-old cultures, whereas glutamate induced a pronounced formation in 6-day-old cultures. The calcium ionophore A23187 (2 µM) stimulated, within 2 h, formation of NAPE in 2-day-old cultures (fourfold) as well as in 6-day-old cultures (eightfold). Glutamate exerted its effect via NMDA...

  3. The inflammatory and tumor-promoting sesquiterpene lactone, thapsigargin, activates platelets by selective mobilization of calcium as shown by protein phosphorylations

    DEFF Research Database (Denmark)

    Thastrup, Ole; Linnebjerg, H; Bjerrum, P J

    1987-01-01

    , raised cytoplasmic free calcium level and phosphorylation of platelet proteins was examined in platelet-rich plasma and washed platelet suspension. In contrast to A23187 and thrombin, the platelet activation induced by thapsigargin developed slowly, with maximal response obtained after 2-3 min. Both...... obtained by stimulation of the passive calcium transport through specific channels. These thapsigargin-sensitive channels should predominantly be located in the membranes of intracellular calcium stores rather than in the plasma membrane, because removal of extracellular calcium by EGTA had only...

  4. Effect of ionophores and selenium supplementation on the ...

    African Journals Online (AJOL)

    Unknown

    Short paper and poster abstracts: 38th Congress of the South African Society of Animal Science. The South African Journal of Animal Science is available online at http://www.sasas.co.za/Sajas.html. 131. Effect of ionophores and selenium supplementation on the composition of long-chain fatty acid in carcass fat of steers.

  5. Ionophores in polymeric membranes for selective ion recognition; impedance studies

    Energy Technology Data Exchange (ETDEWEB)

    Lisowska-Oleksiak, A. [Department of Chemical Technology, Gdansk University of Technology, ul. Narutowicza 11/12, 80-952 Gdansk (Poland)]. E-mail: alo@chem.pg.gda.pl; Lesinska, U. [Department of Chemical Technology, Gdansk University of Technology, ul. Narutowicza 11/12, 80-952 Gdansk (Poland); Nowak, A.P. [Department of Chemical Technology, Gdansk University of Technology, ul. Narutowicza 11/12, 80-952 Gdansk (Poland); Bochenska, M. [Department of Chemical Technology, Gdansk University of Technology, ul. Narutowicza 11/12, 80-952 Gdansk (Poland)]. E-mail: marboch@chem.pg.gda.pl

    2006-02-15

    Synthetic calix[4]arene-crown ionophores for selective Na{sup +} (ionophore L1) and Cs{sup +}-ions (ionophore L2) recognition find application in ion-selective membrane electrodes (ISE) for analytical purpose. Selectivity coefficients for the electrodes with compounds L1 and L2 are logK{sub Na,Cs}{sup pot}=-2.6 and logK{sub Cs,Na}{sup pot}=-2.4, respectively. Electrodes of two different construction: all-solid-state (ASS) (with conducting polymer layer on glassy carbon or platinum as ion-to-electron transducer) and conventional ion-selective electrode (ISE) (with liquid electrolyte and Ag/AgCl) are presented and their properties and lifetime are being compared. Resistance of PVC membrane with ionophores L1 and L2 were within the range 0.15-1.4M{omega} depending on the type of the outer electrolyte and its concentration. Conductivity of the membranes was in the range 0.7x10{sup -8} to 6x10{sup -8}{omega}{sup -1}cm{sup -1}. Warburg coefficients {sigma} were within 0.16x10{sup 4} to 12.7x10{sup 4}{omega}s{sup -1/2}, dielectric constant values {epsilon} were in a range 28-60 depending mainly on the type of plasticizer.

  6. Synthesis and anticancer properties of water-soluble zinc ionophores.

    Science.gov (United States)

    Magda, Darren; Lecane, Philip; Wang, Zhong; Hu, Weilin; Thiemann, Patricia; Ma, Xuan; Dranchak, Patricia K; Wang, Xiaoming; Lynch, Vincent; Wei, Wenhao; Csokai, Viktor; Hacia, Joseph G; Sessler, Jonathan L

    2008-07-01

    Several water-solubilized versions of the zinc ionophore 1-hydroxypyridine-2-thione (ZnHPT), synthesized as part of the present study, have been found both to increase the intracellular concentrations of free zinc and to produce an antiproliferative activity in exponential phase A549 human lung cancer cultures. Gene expression profiles of A549 cultures treated with one of these water-soluble zinc ionophores, PCI-5002, reveal the activation of stress response pathways under the control of metal-responsive transcription factor 1 (MTF-1), hypoxia-inducible transcription factor 1 (HIF-1), and heat shock transcription factors. Additional oxidative stress response and apoptotic pathways were activated in cultures grown in zinc-supplemented media. We also show that these water-soluble zinc ionophores can be given to mice at 100 micromol/kg (300 micromol/m(2)) with no observable toxicity and inhibit the growth of A549 lung and PC3 prostate cancer cells grown in xenograft models. Gene expression profiles of tumor specimens harvested from mice 4 h after treatment confirmed the in vivo activation of MTF-1-responsive genes. Overall, we propose that water-solubilized zinc ionophores represent a potential new class of anticancer agents.

  7. Use of ionophores in lactating dairy cattle: a review.

    Science.gov (United States)

    Duffield, T F; Bagg, R N

    2000-01-01

    Ionophores are feed additives that alter rumen microbial populations through ion transfer across cell membranes. Although ionophores have been used widely in the beef industry for improved feed efficiency and control of coccidiosis, there has been limited use by the dairy industry. In Canada, the label warning prohibiting the use of monensin premix in lactating dairy cattle was removed in June 1996. Following this, in December 1997, a controlled release capsule containing monensin was approved for use in dairy cattle as an aid to prevent subclinical ketosis. Monensin may have several advantages for dairy cattle, including improved energy metabolism, increased milk production, and altered milk components. This literature review was primarily conducted in 1996 by using the Agricola and CAB search databases. Other relevant articles published since the search (up to 1998) have been added. This review will provide practitioners with relevant references in the published literature regarding ionophore use in dairy cattle. It should also give some guidance as to what effects might be anticipated with the use of ionophores in lactating dairy animals. PMID:10816832

  8. ERK1/2 mediates sperm acrosome reaction through elevation of intracellular calcium concentration.

    Science.gov (United States)

    Jaldety, Yael; Breitbart, Haim

    2015-10-01

    Mammalian sperm acquire fertilization capacity after residing in the female reproductive tract for a few hours in a process called capacitation. Only capacitated sperm can bind the zona pellucida (ZP) of the egg and undergo the acrosome reaction, a process that allows penetration and fertilization. Extracellular signal regulated kinase (ERK1/2) mediates signalling in many cell types, however its role in sperm function is largely unknown. Here we show that ERK1/2 is highly phosphorylated/activated after a short incubation of mouse sperm under capacitation conditions and that this phosphorylation is reduced after longer incubation. Further phosphorylation was observed upon addition of crude extract of egg ZP or epidermal growth factor (EGF). The mitogen-activated ERK-kinase (MEK) inhibitor U0126 abolished ERK1/2 phosphorylation, in vitro fertilization rate and the acrosome reaction induced by ZP or EGF but not by the Ca2+-ionophore A23187. Moreover, inhibition of ERK1/2 along the capacitation process diminished almost completely the sperm's ability to go through the acrosome reaction, while inhibition at the end of capacitation attenuated the acrosome reaction rate by only 45%. The fact that the acrosome reaction, induced by the Ca2+ -ionophore A23187, was not inhibited by U0126 suggests that ERK1/2 mediates the acrosome reaction by activating Ca2+ transport into the cell. Direct determination of intracellular [Ca2+] revealed that Ca2+ influx induced by EGF or ZP was completely blocked by U0126. Thus, it has been established that the increase in ERK1/2 phosphorylation/activation in response to ZP or by activation of the EGF receptor (EGFR) by EGF, is a key event for intracellular Ca2+ elevation and the subsequent occurrence of the acrosome reaction.

  9. Helical peptide-polyamine and -polyether conjugates as synthetic ionophores.

    Science.gov (United States)

    Benincasa, Monica; Francescon, Marco; Fregonese, Massimo; Gennaro, Renato; Pengo, Paolo; Rossi, Paola; Scrimin, Paolo; Tecilla, Paolo

    2015-12-01

    Two new synthetic ionophores in which the hydrophobic portion is represented by a short helical Aib-peptide (Aib=α-amino-isobutyric acid) and the hydrophilic one is a poly-amino (1a) or a polyether (1b) chain have been prepared. The two conjugates show a high ionophoric activity in phospholipid membranes being able to efficiently dissipate a pH gradient and, in the case of 1b, to transport Na(+) across the membrane. Bioactivity evaluation of the two conjugates shows that 1a has a moderate antimicrobial activity against a broad spectrum of microorganisms and it is able to permeabilize the inner and the outer membrane of Escherichia coli cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Quartz crystal microbalance sensor using ionophore for ammonium ion detection.

    Science.gov (United States)

    Kosaki, Yasuhiro; Takano, Kosuke; Citterio, Daniel; Suzuki, Koji; Shiratori, Seimei

    2012-01-01

    Ionophore-based quartz crystal microbalance (QCM) ammonium ion sensors with a detection limit for ammonium ion concentrations as low as 2.2 microM were fabricated. Ionophores are molecules, which selectively bind a particular ion. In this study, one of the known ionophores for ammonium, nonactin, was used to detect ammonium ions for environmental in-situ monitoring of aquarium water for the first time. To fabricate the sensing films, poly(vinyl chloride) was used as the matrix for the immobilization of nonactin. Furthermore, the anionic additive, tetrakis (4-chlorophenyl) borate potassium salt and the plasticizer dioctyl sebacate were used to enhance the sensor properties. The sensor allowed detecting ammonium ions not only in static solution, but also in flowing water. The sensor showed a nearly linear response with the increase of the ammonium ion concentration. The QCM resonance frequency increased with the increase of ammonium ion concentration, suggesting a decreasing weight of the sensing film. The detailed response mechanism could not be verified yet. However, from the results obtained when using a different plasticizer, nitrophenyl octyl ether, it is considered that this effect is caused by the release of water molecules. Consequently, the newly fabricated sensor detects ammonium ions by discharge of water. It shows high selectivity over potassium and sodium ions. We conclude that the newly fabricated sensor can be applied for detecting ammonium ions in aquarium water, since it allows measuring low ammonium ion concentrations. This sensor will be usable for water quality monitoring and controlling.

  11. Efficacy of ionophores in cattle diets for mitigation of enteric methane.

    Science.gov (United States)

    Guan, H; Wittenberg, K M; Ominski, K H; Krause, D O

    2006-07-01

    Use of ionophores in cattle diets has been proposed as a strategy for mitigation of enteric CH4 emissions. Short- and long-term effects of feeding a single ionophore (monensin) or rotation of 2 ionophores (monensin and lasalocid) on enteric CH4 emissions were evaluated in 36 Angus yearling steers (328 +/- 24.9 kg of BW) over a 16-wk period. Steers were randomly assigned to 6 dietary treatments of 6 steers each. The 6 diets were low-concentrate without ionophore supplementation, low-concentrate with monensin supplementation, low-concentrate with a 2-wk rotation of monensin and lasalocid supplementation, high-concentrate without ionophore supplementation, high-concentrate with monensin supplementation, and high-concentrate with a 2-wk rotation of monensin and lasalocid supplementation. Daily enteric CH4 emissions, as measured using the SF(6) tracer gas technique, ranged from 54.7 to 369.3 L/steer daily. Supplementing ionophores decreased (P ionophores did not (P > 0.05) exhibit a greater decrease and did not (P > 0.05) have a longer period of depressed enteric CH4 emissions compared with cattle receiving monensin only. Ionophore supplementation did not (P > 0.05) alter total ruminal fluid VFA concentration; however, the acetate:propionate ratio and ammonia-N concentration in ruminal fluid were decreased (P ionophores were introduced to the time they were removed from the diets. Both monensin and the rotation of monensin and lasalocid decreased (P ionophores on enteric CH(4) production are related to ciliate protozoal populations and that ciliate protozoal populations can adapt to the ionophores present in either low- or high-concentrate diets. Rotation of monensin and lasalocid did not (P > 0.05) prevent ciliate protozoal adaptation to ionophores.

  12. Ionophores and receptors using cation-π interactions: Collarenes

    Science.gov (United States)

    Choi, Hyuk Soon; Suh, Seung Bum; Cho, Seung Joo; Kim, Kwang S.

    1998-01-01

    Cation-π interactions are important forces in molecular recognition by biological receptors, enzyme catalysis, and crystal engineering. We have harnessed these interactions in designing molecular systems with circular arrangement of benzene units that are capable of acting as ionophores and models for biological receptors. [n]Collarenes are promising candidates with high selectivity for a specific cation, depending on n, because of their structural rigidity and well-defined cavity size. The interaction energies of [n]collarenes with cations have been evaluated by using ab initio calculations. The selectivity of these [n]collarenes in aqueous solution was revealed by using statistical perturbation theory in conjunction with Monte Carlo and molecular dynamics simulations. It has been observed that in [n]collarenes the ratio of the interaction energies of a cation with it and the cation with the basic building unit (benzene) can be correlated to its ion selectivity. We find that collarenes are excellent and efficient ionophores that bind cations through cation-π interactions. [6]Collarene is found to be a selective host for Li+ and Mg2+, [8]collarene for K+ and Sr2+, and [10]collarene for Cs+ and Ba2+. This finding indicates that [10]collarene and [8]collarene could be used for effective separation of highly radioactive isotopes, 137Cs and 90Sr, which are major constituents of nuclear wastes. More interestingly, collarenes of larger cavity size can be useful in capturing organic cations. [12]Collarene exhibits a pronounced affinity for tetramethylammonium cation and acetylcholine, which implies that it could serve as a model for acetylcholinestrase. Thus, collarenes can prove to be novel and effective ionophores/model-receptors capable of heralding a new direction in molecular recognition and host-guest chemistry. PMID:9770445

  13. Development of a disposable mercury ion-selective optode based on tritylpicolinamide as ionophore

    NARCIS (Netherlands)

    Kuswandi, Bambang; Nuriman, [Unknown; Dam, H.H.; Reinhoudt, David; Verboom, Willem

    2007-01-01

    A disposable ion-selective optode for mercury based on trityl-picolinamide (T-Pico) as neutral ionophore was developed. The sensing layer consist of plasticised PVC incorporating T-Pico as a selective ionophore for Hg2+, ETH 5418 as a chromoionophore, and potassium

  14. Study on poly(ethylene-oxide) electrolytes with ionophores for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lisowska-Oleksiak, A.; Inerowicz, H.D. [Technical Univ. Gdansk (Poland). Dept. of Chemistry

    1999-09-01

    Kinetics and mechanism for the electrodeposition of lithium from tetraethylene glycol dimethyl ether electrolytes formed from lithium perchlorate and ionophores have been studied using voltammetric and chronoamperometric methods at Pt and Au electrodes. The ionophore influence on stripping efficiencies, nucleation overpotentials, exchange current densities was evaluated. The type of nucleation and crystal growth process was determined. (orig.)

  15. Effects of ionophores on Enterococcus faecalis and E. faecium growth in pure and mixed ruminal culture.

    Science.gov (United States)

    Nisbet, David J; Callaway, Todd R; Edrington, Tom S; Anderson, Robin C; Poole, Toni L

    2008-04-01

    Enterococcus faecalis and E. faecium are gram-positive human pathogens that can live in the gastrointestinal tract of food animals. Vancomycin-resistant enterococci are an increasing threat to humans as a nosocomial infection, as well as a reservoir of antibiotic resistance genes. Ionophores are feed-grade antimicrobials that are widely used to enhance the ruminal fermentation efficiency via inhibiting gram-positive bacteria by dissipating ion and proton gradients. Some bacteria can become resistant to ionophores, and this has prompted concerns about whether ionophore resistance can enhance antibiotic resistance in intestinal bacteria. Since enterococci are normal members of the ruminant intestinal tract and function as an antibiotic resistance reservoir, the present study investigated whether treatment with the most commonly used ionophores affected the growth of enterococci, and whether ionophore-resistant enterococci developed. Ionophores do inhibit the growth of enterococci in pure culture, but in our study did not alter populations in mixed ruminal bacterial culture. Ionophore-resistant isolates were not isolated during this study from pure or mixed cultures. Our results indicate that the role of ionophores in the dissemination of antibiotic resistance genes through the intestinal Enterococcus spp. appears to be limited.

  16. Silver selective electrodes based on thioether functionalized calix[4]arenes as ionophores

    NARCIS (Netherlands)

    Malinowska, Elz˙bieta; Brzozka, Zbigniew; Kasiura, Krzysztof; Egberink, Richard J.M.; Reinhoudt, David

    1994-01-01

    Silver selective electrodes based on thioether functionalized calix[4]arenes 1 and 2 as ionophores were investigated. For both ionophores the selectivity coefficients (log kAg,M) were lower than −2.2 for Hg(II) and lower than −4.6 for other cations tested. The best results were obtained with

  17. Lead selective electrodes based on thioamide functionalized calix[4]arenes as ionophores

    NARCIS (Netherlands)

    Malinowska, Elz˙bieta; Brzozka, Zbigniew; Kasiura, Krzysztof; Egberink, Richard J.M.; Reinhoudt, David

    1994-01-01

    Lead selective electrodes based on a di- and tetrathioamide functionalized calix [4] arene as ionophores were investigated. The Pb(II)-response functions exhibited almost theoretical Nernstian slopes in the activity range 10¿6¿10¿2M of lead ions. For both ionophores a preference for lead over other

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

    DEFF Research Database (Denmark)

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

    1990-01-01

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

  19. Selective zinc ion detection by functionalised ZnO nanorods with ionophore

    Science.gov (United States)

    Ibupoto, Z. H.; Usman Ali, Syed M.; Chey, C. O.; Khun, K.; Nur, O.; Willander, Magnus

    2011-11-01

    In this paper, highly dense and well aligned single-crystal zinc oxide nanorods were grown along the c-axis on a gold coated glass substrate using a low temperature aqueous chemical growth approach. The prepared ZnO nanorods were functionalized with plastic membrane coatings containing specific ionophore (12-crown-4) which is highly selective to zinc ions (Zn+2). The electrochemical response of the sensor was found to be linear over a relatively wide logarithmic concentration range from 1 μM to 100 mM. The proposed sensor showed a good linearity with a high sensitivity of ˜35 mV/decade for sensing Zn+2 ions. A fast response time of less than 5 s with a good selectivity, repeatability, reproducibility, and negligible response to common interferents ions such as calcium (Ca2+), magnesium (Mg2+), or potassium (K+), and iron (Fe+3) and copper (Cu+2) was also demonstrated. Moreover, the proposed sensor showed good stoichiometric results for potentiometric titration.

  20. Pharmacologic characterization of the Na+ ionophores in L6 myotubes.

    Science.gov (United States)

    Sastre, A; Podleski, T R

    1976-01-01

    We present a pharmacologic characterization of the Na+ ionophores present in L6 myotubes in vitro. Action potentials are abolished by replacement of the external Na+ by Tris. The amplitude of the action potential is generally resistant to high concentrations of tetrodotoxin (10(-5) M) and saxitoxin (10(-6 M), but the effect of these agents is highly variable. Veratridine (10(-4 M) consistently induces, as a short-term effect, a marked prolongation of the falling phase of the action potential. As a long-term effect, veratridine consistently induces a Na+-dependent reduction in the resting potential of the cell. The effects of veratridine on the action potential are not antagonized by tetrodotoxin or saxitoxin. However, the effects of veratridine on the resting potential are strongly antagonized by tetrodotoxin (10(-5) M) and fully inhibited by saxitoxin (10(-6) M). Significantly, under conditions where saxitoxin has fully inhibited the effects of veratridine on the resting potential, the myotubes are capable of generating overshooting action potentials. In contrast to their sensitivity to veratridine, L6 myotubes are insensitive to 10(-5) M alpha-dihydro-grayanotoxin-II. These results are discussed in the contexts of developmental significance and current views about Na+ ionophores. PMID:1063416

  1. Stacking Time and Aluminum Sulfate Effects on Polyether Ionophores in Broiler Litter.

    Science.gov (United States)

    Doydora, Sarah A; Sun, Peizhe; Cabrera, Miguel; Thompson, Aaron; Love-Myers, Kimberly; Rema, John; Calvert, Vaughn; Pavlostathis, Spyros G; Huang, Ching-Hua

    2015-11-01

    The use of ionophores as antiparasitic drugs plays an important role in US poultry production, especially in the broiler () industry. However, administered ionophores can pass through the bird's digestive system and appear in broiler litter, which, when applied to agricultural fields, can present an environmental hazard. Stacking (storing or stockpiling) broiler litter for some time might decrease the litter ionophore concentrations before land application. Because ionophores undergo abiotic hydrolysis at low pH, decreasing litter pH with acidic aluminum sulfate (alum) might also decrease ionophore concentrations. We assessed the change in ionophore concentrations in broiler litter in response to the length of time broiler litter was stored (stacking time) and alum addition. We spiked broiler litter with monensin and salinomycin, placed alum-amended litter (∼pH 4-5) and unamended litter (∼pH 8-9) into 1.8-m bins, and repeatedly sampled each bin for 112 d. Our findings showed that stacking broiler litter alone did not have an impact on monensin concentration, but it did slowly reduce salinomycin concentration by 55%. Adding alum to broiler litter reduced monensin concentration by approximately 20% relative to unamended litter, but it did not change salinomycin concentration. These results call for continued search for alternative strategies that could potentially reduce the concentration of ionophores in broiler litter before their application to agricultural soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Alum and Rainfall Effects on Ionophores in Runoff from Surface-Applied Broiler Litter.

    Science.gov (United States)

    Doydora, Sarah A; Franklin, Dorcas; Sun, Peizhe; Cabrera, Miguel; Thompson, Aaron; Love-Myers, Kimberly; Rema, John; Calvert, Vaughn; Pavlostathis, Spyros G; Huang, Ching-Hua

    2015-09-01

    Polyether ionophores, monensin, and salinomycin are commonly used as antiparasitic drugs in broiler production and may be present in broiler litter (bird excreta plus bedding material). Long-term application of broiler litter to pastures may lead to ionophore contamination of surface waters. Because polyether ionophores break down at low pH, we hypothesized that decreasing litter pH with an acidic material such as aluminum sulfate (alum) would reduce ionophore losses to runoff (i.e., monensin and salinomycin concentrations, loads, or amounts lost). We quantified ionophore loss to runoff in response to (i) addition of alum to broiler litter and (ii) length of time between litter application and the first simulated rainfall event. The factorial experiment consisted of unamended (∼pH 9) vs. alum-amended litters (∼pH 6), each combined with simulated rainfall at 0, 2, or 4 wk after litter application. Runoff from alum-amended broiler litter had 33% lower monensin concentration ( broiler litter when averaged across all events of rainfall. Ionophore losses to runoff were also less when rainfall was delayed for 2 or 4 wk after litter application relative to applying rainfall immediately after litter application. While the weather is difficult to predict, our data suggest that ionophore losses in runoff can be reduced if broiler litter applications are made to maximize dry time after application. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. Ionophores: their use as ruminant growth promotants and impact on food safety.

    Science.gov (United States)

    Callaway, T R; Edrington, T S; Rychlik, J L; Genovese, K J; Poole, T L; Jung, Y S; Bischoff, K M; Anderson, R C; Nisbet, David J

    2003-09-01

    Ionophores (such as monensin, lasalocid, laidlomycin, salinomycin and narasin) are antimicrobial compounds that are commonly fed to ruminant animals to improve feed efficiency. These antimicrobials specifically target the ruminal bacterial population and alter the microbial ecology of the intestinal microbial consortium, resulting in increased carbon and nitrogen retention by the animal, increasing production efficiency. Ionophores transport ions across cell membranes of susceptible bacteria, dissipating ion gradients and uncoupling energy expenditures from growth, killing these bacteria. Not all bacteria are susceptible to ionophores, and several species have been shown to develop several mechanisms of ionophore resistance. The prophylactic use of antimicrobials as growth promotants in food animals has fallen under greater scrutiny due to fears of the spread of antibiotic resistance. Because of the complexity and high degree of specificity of ionophore resistance, it appears that ionophores do not contribute to the development of antibiotic resistance to important human drugs. Therefore it appears that ionophores will continue to play a significant role in improving the efficiency of animal production in the future.

  4. Effects of thapsigargin in isolated rat thoracic aorta

    DEFF Research Database (Denmark)

    Mikkelsen, E O; Thastrup, Ole; Christensen, S B

    1988-01-01

    a concentration related relaxation and shifted the K+-concentration response curve to the right and depressed the maximal response to K+. Removal of vascular endothelium abolished the relaxant response to Tg and increased the sensitivity of the preparations to the contractile effect of Tg. The contractile......, but had no effect on the Tg or on the calcium ionophore A 23187 evoked relaxation. Ultraviolet radiation decreased the relaxant effect of Tg and A 23187 without affecting the carbachol induced relaxations. The results showed that vascular endothelium depressed the contractile effect of Tg and that Tg like...... A 23187 had an endothelium dependent relaxant effect on rat aorta different from that of carbachol. The results indicate that Tg in vascular smooth muscle acts by stimulating the transmembranal influx of extracellular calcium....

  5. New polymeric membrane cadmium(II)-selective electrodes using tripodal amine based ionophores

    Energy Technology Data Exchange (ETDEWEB)

    Khamjumphol, Utisawadee [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Watchasit, Sarayut [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Suksai, Chomchai [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Burapha University, Chonburi 20131 (Thailand); Janrungroatsakul, Wanwisa [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Boonchiangma, Suthasinee [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Tuntulani, Thawatchai [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Ngeontae, Wittaya, E-mail: wittayange@kku.ac.th [Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen 40002 (Thailand); National Center of Excellence for Environmental and Hazardous Waste Management, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2011-10-17

    Highlights: {yields} New four ionophores having tripodal amine (TPA) unit on anthracene and calixarene. {yields} Synthesis and characterization data were reported. {yields} Incorporated to the plasticized PVC membranes to prepare Cd-ISEs. {yields} Two TPA units on calixarene showed the best selectivity toward Cd{sup 2+}. {yields} Applied for sensing Cd{sup 2+} from the oxidation of CdS QDs solution. - Abstract: Fabrication of PVC membrane electrodes incorporating selective neutral carriers for Cd{sup 2+} was reported. The ionophores were designed to have different topologies, donor atoms and lipophilicity by attaching tripodal amine (TPA) units to the lipophilic anthracene (ionophore I) and p-tert-butylcalix[4]arene (ionophores II, III and IV). The synthesized ionophores were incorporated to the plasticized PVC membranes to prepare Cd(II) ion selective electrodes (ISEs). The membrane electrodes were optimized by changing types and amounts of ionic sites and plasticizers. The selectivity of the membranes fabricated from the synthesized ionophores was evaluated, the relationship between structures of ionophores and membrane characteristics were explored. The ionophore IV which composed of two opposites TPA units on the calix[4]arene compartment showed the best selectivity toward Cd{sup 2+}. The best membrane electrode was fabricated from ionophore IV (10.2 mmol kg{sup -1}) with KTpClPB (50.1 mol% related to the ionophore) as an ion exchanger incorporated in the DOS plasticized PVC membrane (1:2; PVC:DOS). The Cd-ISE fabricated from ionophore IV exhibited good properties with a Nernstian response of 29.4 {+-} 0.6 mV decade{sup -1} of activity for Cd{sup 2+} ions and a working concentration range of 1.6 x 10{sup -6}-1.0 x 10{sup -2} M. The sensor has a fast response time of 10 s and can be used for at least 1 week without any divergence in potential. The electrode can be used in the pH range of 6.0-9.0. The proposed electrodes using ionophores III and IV were employed

  6. Extraction and detection of Ionophores in the Aquatic Environment

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen

    are more than 10 tonnes in Denmark and for the Republic of Korea more than 800 tonnes (Hansen et al. 2009a, Kim et al. 2008). Ionophores are antibiotic drugs that form lipid soluble complexes with, primarily, alkali cations that inhibit or kill pathogenic parasites in livestock. Several reports have......-performance liquid chromatography tandem in space mass spectrometry. Halling-Sørensen B, Sengelov G, Tjørnelund J (2002) Arch Environ Contam Toxicol, 42: 3, pp. 263-271 Dolliver H, Gupta S (2008) J. Environ. Qual. 37: 2 pp. 1227-1237. Hansen M, Björklund E, Krogh KA, Halling-Sørensen B (2009a) TrAC 28:5 pp521...

  7. Calix[4]arene-cholic acid conjugates: a new class of efficient synthetic ionophores.

    Science.gov (United States)

    Maulucci, Nakia; De Riccardis, Francesco; Botta, Cinzia Barbara; Casapullo, Agostino; Cressina, Elena; Fregonese, Massimo; Tecilla, Paolo; Izzo, Irene

    2005-03-14

    The synthesis of a new class of amphiphilic calix[4]arene-based ionophores, relying on direct reductive amination as a key step, and the evaluation of their H+ and Na+ transporting properties is described.

  8. Ionophore-based titrimetric detection of alkali metal ions in serum

    OpenAIRE

    Zhai, Jingying; Xie, Xiaojiang; Cherubini, Thomas John; Bakker, Eric

    2017-01-01

    While the titrimetric assay is one of the most precise analytical techniques available, only a limited list of complexometric chelators is available, as many otherwise promising reagents are not water-soluble. Recent work demonstrated successful titrimetry with ion-exchanging polymeric nanospheres containing hydrophobic complexing agents, so-called ionophores, opening an exciting avenue in this field. However, this method was limited to ionophores of very high affinity to the analyte and exhi...

  9. Transformation of ionophore antimicrobials in poultry litter during pilot-scale composting.

    Science.gov (United States)

    Munaretto, Juliana S; Yonkos, Lance; Aga, Diana S

    2016-05-01

    Ionophores are the second top selling class of antimicrobials used in food-producing animals in the United States. In chickens, ionophores are used as feed additives to control coccidiosis; up to 80% of administered ionophores are excreted in the litter. Because poultry litter is commonly used to fertilize agricultural fields, ionophore residues in litter have become contaminants of emerging concern. This study aims to develop a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify ionophores, and identify their transformation products (TPs) in poultry litter after on-farm pilot-scale composting. The validation parameters of the optimized method showed good accuracy, ranging from 71 to 119% recovery and relative standard deviation (precision) of ≤19% at three different concentration levels (10, 50 and 100 μg/kg). Monensin, salinomycin and narasin, were detected in the poultry litter samples prior to composting at 290.0 ± 40, 426 ± 46, and 3113 ± 318 μg kg(-1), respectively. This study also aims to investigate the effect of different composting conditions on the removal of ionophores, such as the effect of turning or aeration. Results revealed a 13-68% reduction in ionophore concentrations after 150 d of composting, depending on whether the compost was aerated, turned, or subjected to a combination of both aeration and turning. Three transformation products and one metabolite of ionophores were identified in the composted litter using high-resolution liquid chromatography with quadrupole time-of-flight mass spectrometry (LC-QToF/MS). Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin

    OpenAIRE

    Tanabe Makoto; Simova Svetlana; Mitewa Mariana; Pantcheva Ivayla N; Ivanova Juliana; Osakada Kohtaro

    2011-01-01

    Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in in vivo experiments, despite so far no Pb(II)-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as poss...

  11. A collection of yeast mutants selectively resistant to ionophores acting on mitochondrial inner membrane.

    Science.gov (United States)

    Petrezselyova, Silvia; Lalakova, Jana; Abelovska, Lenka; Klobucnikova, Vlasta; Tomaska, Lubomir

    2008-03-01

    Valinomycin and nigericin are potassium ionophores acting selectively on the mitochondrial inner membrane of Saccharomyces cerevisiae [Kovac, L., Bohmerova, E., Butko, P., 1982a. Ionophores and intact cells. I. Valinomycin and nigericin act preferentially on mitochondria and not on the plasma membrane of Saccharomyces cerevisiae. Biochim. Biophys. Acta 721, 341-348]. However, the molecular mechanism of their action is not understood. Here we show that their selective effect on mitochondrial membranes is not caused by the pleiotropic drug resistance system. To identify the molecular components mediating the action of ionophores we isolated several mutants specifically resistant to valinomycin and/or nigericin. In contrast to the parental strain, these mutants do not form respiratory-deficient cells in the presence of ionophores. Moreover, all mutants harbor extensively fragmented mitochondria and these morphological defects can be alleviated by the ionophores. Interestingly, we observed that these mitochondrial defects may be accompanied by changes in vacuolar dynamics. Our results demonstrate that the classical genetic approach can provide a starting point for the analysis of components involved in the action of ionophores on mitochondria-related processes in eukaryotic cell.

  12. Free Base Porphyrins as Ionophores for Heavy Metal Sensors

    Directory of Open Access Journals (Sweden)

    Liliana Olenic

    2008-08-01

    Full Text Available Two functionalized porphyrins: 5,10,15,20-tetrakis(3,4-dimethoxyphenyl porphyrin (A and 5,10,15,20-tetrakis(3-hydroxyphenylporphyrin (B obtained and characterized by us were used as ionophores (I for preparing PVC-based membrane sensors selective to Ag+, Pb2+ and Cu2+. The membranes were prepared using three different plasticizers: (bis(2-ethylhexylsebacate (DOS, dioctylphtalate (DOP, o-nitrophenyl octyl ether (NPOE and potassium tetrakis(4-chlorophenylborate (KTClPB as additive. The functional parameters (linear concentration range, slope and selectivity of the sensors with membrane composition: (I:PVC:KTClPB:Plasticizer in different ratios were investigated. The best results were obtained for the membranes in the ratio I:PVC:KTClPB:Plasticizer 10:165:5:330. The influence of pH on the sensors response was studied. The sensors were used for a period of four months and their utility has been tested on synthetic and real samples.

  13. Photodegradation of veterinary ionophore antibiotics under UV and solar irradiation.

    Science.gov (United States)

    Sun, Peizhe; Pavlostathis, Spyros G; Huang, Ching-Hua

    2014-11-18

    The veterinary ionophore antibiotics (IPAs) are extensively used as coccidiostats and growth promoters and are released to the environment via land application of animal waste. Due to their propensity to be transported with runoff, IPAs likely end up in surface waters where they are subject to photodegradation. This study is among the first to investigate the photodegradation of three commonly used IPAs, monensin (MON), salinomycin (SAL) and narasin (NAR), under UV and solar irradiation. Results showed that MON was persistent in a deionized (DI) water matrix when exposed to UV and sunlight, whereas SAL and NAR could undergo direct photolysis with a high quantum yield. Water components including nitrate and dissolved organic matter had a great impact on the photodegradation of IPAs. A pseudosteady state kinetic model was successfully applied to predict IPAs' photodegradation rates in real water matrices. Applying LC/MS/MS, multiple photolytic transformation products of IPAs were observed and their structures were proposed. The direct photolysis of SAL and NAR occurred via cleavage on the ketone moiety and self-sensitized photolysis. With the presence of nitrate, MON was primarily degraded by hydroxyl radicals, whereas SAL showed reactivity toward both hydroxyl and nitrogen-dioxide radicals. Additionally, toxicity tests showed that photodegradation of SAL eliminated its antibiotic properties against Bacillus subtilis.

  14. Protonation of sodium ionophore III: Extraction and DFT study

    Science.gov (United States)

    Makrlík, Emanuel; Kvíčala, Jaroslav; Vaňura, Petr

    2014-08-01

    On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq) + 1ṡNa+(nb) ⇆ 1ṡH3O+(nb) + Na+(aq) occurring in the two-phase water-nitrobenzene system (1 = sodium ionophore III; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (H3O+, 1ṡNa+) = 0.0 ± 0.1. Further, the stability constant of the 1ṡH3O+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1ṡH3O+) = 6.4 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1ṡH3O+ was derived. In the resulting complex, the "central" cation H3O+ is bound by two linear hydrogen bonds and one bifurcated hydrogen bond to the corresponding four oxygens of the parent ligand 1. The interaction energy of the considered 1ṡH3O+ complex was found to be -556.6 kJ/mol, confirming also the formation of this cationic species.

  15. Trace Level Determination of Polyether Ionophores in Feed

    Directory of Open Access Journals (Sweden)

    Mervi Rokka

    2013-01-01

    Full Text Available A liquid chromatography-mass spectrometric method was developed and validated to determine six polyether ionophores (lasalocid sodium, monensin sodium, salinomycin sodium, narasin, maduramicin ammonium alpha, and semduramicin sodium in feed samples. The method developed was very straightforward, involving extraction with 84% acetonitrile of the coccidiostats from the feed samples and filtration of the raw extract prior to chromatographic analysis. Method validation included the determination of selectivity, linearity, specificity, repeatability, the limit of detection, limit of quantification, decision limit (CCα, detection capability (CCβ, and recovery. Feed samples from the Finnish national feed control programme and suspected carry-over samples from a feed manufacturer were analysed in parallel with an existing liquid chromatography method coupled with ultraviolet detection. All feed control samples were negative in LC-UV, but with the developed MS method, monensin, salinomycin, and narasin were detected at concentrations of <0.025–0.73 mg/kg, <0.025–0.027 mg/kg, and <0.025–1.6 mg/kg, respectively. In suspected carry-over samples after an output of 2.0 tonnes of unmedicated feed in the pelletizer line, the concentrations of monensin, salinomycin, and narasin varied from undetected to 16 mg/kg. In the mixer line, after 3.2 tonnes of unmedicated feed output, the concentrations of monensin, salinomycin, and narasin varied from undetected to 2.4 mg/kg.

  16. Ultrasmall fluorescent ion-exchanging nanospheres containing selective ionophores.

    Science.gov (United States)

    Xie, Xiaojiang; Mistlberger, Günter; Bakker, Eric

    2013-10-15

    We present a convenient precipitation procedure to fabricate ultrasmall fluorescent ion-selective nanosensors that operate on the basis of bulk ion-exchange sensing principles. The nanosphere matrix is composed of bis(2-ethylhexyl) sebacate (DOS) and a triblock copolymer Pluronic(®) F-127, which also functions as a surfactant to stabilize the nanoparticle. The particles can be prepared easily in large quantity without resorting to further complicated purification. Dynamic light scattering shows that these particles have a monodisperse size distribution with an average diameter of ∼40 nm, suggesting that the nanoparticles are among the smallest ionophore-based ion-selective nanosensors reported to date. A newly reported oxazinoindoline (Ox) as well as a Nile blue derivative (chromoionophore I) was used as a chromoionophore. Na(+)- and H(+)-selective nanospheres were characterized by absorbance and fluorescence spectroscopy. Owing to the very small size of the nanospheres, the suspension containing the particles is transparent. In the additional presence of the pH indicator HPTS, spectroscopic interrogation of pH and Na(+) in the same sample was demonstrated. As an example, the nanospheres were used to measure the Na(+) level in commercial mineral waters, and the results showed good agreement with atomic absorption spectroscopy (AAS).

  17. Trace level determination of polyether ionophores in feed.

    Science.gov (United States)

    Rokka, Mervi; Jestoi, Marika; Peltonen, Kimmo

    2013-01-01

    A liquid chromatography-mass spectrometric method was developed and validated to determine six polyether ionophores (lasalocid sodium, monensin sodium, salinomycin sodium, narasin, maduramicin ammonium alpha, and semduramicin sodium) in feed samples. The method developed was very straightforward, involving extraction with 84% acetonitrile of the coccidiostats from the feed samples and filtration of the raw extract prior to chromatographic analysis. Method validation included the determination of selectivity, linearity, specificity, repeatability, the limit of detection, limit of quantification, decision limit (CC α ), detection capability (CC β ), and recovery. Feed samples from the Finnish national feed control programme and suspected carry-over samples from a feed manufacturer were analysed in parallel with an existing liquid chromatography method coupled with ultraviolet detection. All feed control samples were negative in LC-UV, but with the developed MS method, monensin, salinomycin, and narasin were detected at concentrations of <0.025-0.73 mg/kg, <0.025-0.027 mg/kg, and <0.025-1.6 mg/kg, respectively. In suspected carry-over samples after an output of 2.0 tonnes of unmedicated feed in the pelletizer line, the concentrations of monensin, salinomycin, and narasin varied from undetected to 16 mg/kg. In the mixer line, after 3.2 tonnes of unmedicated feed output, the concentrations of monensin, salinomycin, and narasin varied from undetected to 2.4 mg/kg.

  18. Potentiometric polymeric membrane electrodes for mercury detection using calixarene ionophores.

    Science.gov (United States)

    Tyagi, Sonika; Agarwal, Himanshu; Ikram, Saiqa

    2010-01-01

    It is here established that potentiometric polymeric membrane electrodes based on electrically neutral ionophores are a useful analytical tool for the detection of heavy metal ions from environmental and industrial waste water. PVC based membrane containing p-tert-butyl-calix[4]arenethioether derivative as active material along with sodiumtetraphenylborate (NaTPB) as solvent mediator and dibutylphthalate as a plasticizer in the ratio 45:9:460:310 (w/w%) (I:NaTPB:DBP:PVC) exhibits good properties with a Nernstian response of 29.50+/-1.0 mV per decade of activity and a working concentration range of 7.2 x 10(-8)-1.0 x 10(-1) M. The electrode gave more stable potential readings when used around pH 2.5-6.8 and exhibits fast response time of 14 s. The sensors were found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of acetone, methanol or ethanol and could be used over a period of 7-9 months. Excellent selectivity for Hg(2+) ions is indicated by match potential method and fixed interference method. The sensors could be used successfully in the estimation of mercury in different sample.

  19. Ionophores have limited effects on jejunal glucose absorption and energy metabolism in mice.

    Science.gov (United States)

    Fan, Y K; Croom, J; Eisen, E J; Spires, H R; Daniel, L R

    2003-08-01

    Two experiments, Trial 1 (in vitro) and Trial 2 (in vivo), were conducted to examine the effects of ionophores, monensin, laidlomycin, and laidlomycin propionate on whole-animal O2 consumption, organ weights, jejunal glucose absorption, and O2 utilization, as well as growth, feed and water consumption, and feed efficiency. In Trial 1, 30 male Swiss-Webster mice, 8 wk old, were used to measure the in vitro effects of each of the ionophores at concentrations of 1.62 or 16.2 mM. Six combinations of three ionophores at two concentrations resulted in a total of eight treatments. All eight treatments were exposed to jejunal rings from a single mouse for a total of 30 observations per treatment. Jejunal rings were exposed to each ionophore treatment for 15 min. Laidlomycin propionate (16.2 mM) decreased (P Ionophores were administered via the drinking water for 14 d. No ionophore treatment had any effect on whole-mouse O2 consumption. Monensin increased (P = 0.004) stomach size and decreased (P = 0.049) the efficiency of BW gain compared with controls. Laidlomycin propionate decreased (P = 0.032) the percentage of whole jejunum oxygen consumption due to oubain-sensitive respiration compared with control. The efficiency of intestinal glucose absorption was not changed due to treatment in either trial. Under the conditions of these studies, monensin, laidlomycin, and laidlomycin propionate had minimal and inconsistent effects on jejunal function and energy utilization in mice. This investigation suggests that changes in the energetic requirements of animals treated with ionophores are not an issue in animal production.

  20. Calcium Ionophore, Calcimycin, Kills Leishmania Promastigotes by Activating Parasite Nitric Oxide Synthase

    Czech Academy of Sciences Publication Activity Database

    Grekov, Igor; Pombinho, António R.; Kobets, Tetyana; Bartůněk, Petr; Lipoldová, Marie

    (2017), č. článku 1309485. ISSN 2314-6133 R&D Projects: GA ČR(CZ) GA14-30186S; GA ČR GA16-22346S; GA ČR GP14-35944P; GA ČR GP13-41002P; GA MŠk LO1220; GA MŠk LM2015063; GA MŠk(XE) CZ.2.16/3.1.00/28026 Institutional support: RVO:68378050 Keywords : transmission Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.476, year: 2016

  1. Calcium - urine

    Science.gov (United States)

    Urinary Ca+2; Kidney stones - calcium in urine; Renal calculi - calcium in your urine; Parathyroid - calcium in urine ... Urine calcium level can help your provider: Decide on the best treatment for the most common type of kidney ...

  2. New bis(azobenzocrown)s with dodecylmethylmalonyl linkers as ionophores for sodium selective potentiometric sensors.

    Science.gov (United States)

    Luboch, Elżbieta; Jeszke, Maciej; Szarmach, Mirosław; Łukasik, Natalia

    2016-01-01

    Novel biscrowns 1 and 2 were synthesized from 13-membered azobenzocrown ethers containing bromoalkylenoxy chains in para position relative to the azo group. The synthesized diester molecules are dodecylmethylmalonic acid derivatives differing by the linker length. The synthesized compounds have the potential of being used as sodium ionophores in ion-selective electrodes. They were characterized and used as ionophores in classic and miniature, solid contact (screen-printed and glassy carbon) membrane ion-selective electrodes. Compound 3, a similar monoester derivative of 13-membered azobenzocrown, was synthesized and used in membrane electrodes for comparison. Lipophilicity of new ionophores was determined by TLC. Lipophilicity of bis(azobenzocrown)s was found to be within the range of logPTLC = 12-13. It was observed that the particularly important selectivity coefficients logKNa,K determined for new electrodes, being logKNa,K = -2.5 and -2.6 (SSM, 0.1 M), are better than those of the electrodes featuring seven out of the nine commercially available sodium ionophores. It was concluded that the ionophore 1 creates, in acetone, with sodium iodide, complex of 1:1 stoichiometry (sandwich complex) with stability constant (logK) ca. 3.0.

  3. Structural basis, chemical driving forces and biological implications of flavones as Cu(II) ionophores.

    Science.gov (United States)

    Dai, Fang; Yan, Wen-Jing; Du, Yu-Ting; Bao, Xia-Zhen; Li, Xiu-Zhuang; Zhou, Bo

    2017-07-01

    A main biochemical property of cancer cells, compared with normal cells, is altered redox status including increased levels of copper to maintain their malignant phenotypes. Thus, increasing copper accumulation, by using ionophores, to disrupt abnormal redox homeostasis of cancer cells may be an important anticancer strategy. Naturally occurring molecules with extraordinarily diverse chemical scaffolds are an important source of inspiration for developing copper ionophores. Dietary flavonoids are well-characterized copper chelators and show cancer chemopreventive potential, but their ionophoric role for redox-active copper and the related biological implications have remained unknown. This study reports, for the first time, the structural basis, chemical driving forces and biological implications of flavones (a widely distributed subgroup of flavonoids) as Cu(II) ionophores, and also provides new insights into cancer chemopreventive mechanism of flavones bearing 3(or 5)-hydroxy-4-keto group. 3-Hydroxyflavone surfaced as a potent Cu(II) ionophore to induce the mitochondria-dependent apoptosis of cancer cells in a redox intervention fashion via sequential proton-loss Cu(II) chelation, GSH-driving releasing of copper and protonation-dependent efflux of the neutral ligand. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Effects of the antibiotic ionophores monensin, lasalocid, laidlomycin propionate and bambermycin on Salmonella and E. coli O157:H7 in vitro.

    Science.gov (United States)

    Edrington, T S; Callaway, T R; Varey, P D; Jung, Y S; Bischoff, K M; Elder, R O; Anderson, R C; Kutter, E; Brabban, A D; Nisbet, D J

    2003-01-01

    To examine the effects of ionophores on Salmonella and Escherichia coli O157:H7 in pure and mixed ruminal fluid cultures. Four Salmonella serotypes (Dublin, Derby, Typhimurium, and Enteriditis) and two strains of E. coli O157:H7 (ATCC 43895 and FDIU 6058) were cultured in the presence of varying concentrations of ionophores (monensin, lasalocid, laidlomycin propionate, and bambermycin) in pure and mixed ruminal fluid cultures. Bacterial growth rates in pure culture were not affected (P > 0.10) by ionophores at concentrations up to 10 times the approximate rumen ionophore concentration under normal feeding regimens. Likewise, ionophores had no effect (P > 0.10) on Salmonella or E. coli CFU plated from 24-h ruminal fluid incubations. Ionophore treatment decreased (P Ionophores had no effect on the foodborne pathogens Salmonella and E. coli O157:H7 in vitro. The results suggest that ionophore feeding would have little or no effect on Salmonella or E. coli populations in the ruminant.

  5. Synthesis selective transport properties of cleft-type ionophores having two convergent hydroxamic acid functions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Duck Hee; Choi, Mi Jung; Chang, Suk Kyu [Chungang Univ., Seoul (Korea, Republic of)

    2001-07-01

    A series of cleft-type ionophores having two convergent hydroxamic acid functions are prepared and their selective ionophoric properties toward heavy metal and transition metal ions have been investigated. Hydroxamic acids 3 exhibited a prominent selectivity toward heavy metal ions of Hg{sup 2+} and Pb{sup 2+} , and transition metal ions of Cu{sup 2+} over other transition metal and alkaline earth metal ions from slightly acidic source phase (pH 6) to an acidic receiving phase (pH 1). Selective ionophoric properties toward Pb{sup 2+} and Cu{sup 2+} ions over other surveyed metal ions are also confirmed by the FAB-MS measurements.

  6. Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk

    2013-01-01

    A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid......-35%) for poultry manure. The final method allowed for the detection of four ionophores down to a few hundred ngkg(-1) in natural solid matrices with limit of quantifications (LOQs) being 0.96, 0.87, 0.98, and 0.64μgkg(-1) in soil for lasalocid, monensin, salinomycin, and narasin, respectively. Corresponding LOQs...... in sediment were 1.28, 1.34, 1.39, and 0.78μgkg(-1) for the respective ionophores, while in manure the LOQs were 0.98, 1.01, 1.45, and 1.01μgkg(-1)....

  7. Mechanism of uncoupling in mitochondria: uncouplers as ionophores for cycling cations and protons.

    Science.gov (United States)

    Kessler, R J; Tyson, C A; Green, D E

    1976-01-01

    Classical uncouplers such as 2,4-dinitrophenol have been shown to be ionophores with the capability for transporting monovalent or divalent cations with equal efficiency. The conditions appropriate for the maximal expression of this ionophoric capability have been explored. Two critical factors are the polarity of the organic phase and the pH of the aqueous phase that is equilibrated with the organic phase. The demonstrated cationic ionophoric capability of uncouplers, taken in conjunction with the known ability of uncouplers to cycle protons across a membrane phase, provides the experimental basis for the thesis that uncoupling of electron flow from ATP synthesis via classical uncouplers involves the substitution of one coupled process by another. Uncoupling thus reduces to the replacement of one driven reaction (ATP synthesis) by the driven reaction (cyclical transport) mediated by the uncoupler. PMID:9641

  8. Microspheres aided introduction of ionophore and ion-exchanger to the ion-selective membrane.

    Science.gov (United States)

    Wojciechowski, Marcin; Kisiel, Anna; Bulska, Ewa; Michalska, Agata

    2012-01-15

    In this work a novel method for introduction of ionophore and ion-exchanger to the ion-selective polyacrylate based membrane is proposed. These compounds (and optionally primary ions) are introduced to polyacrylate microspheres, used to prepare ion-selective membrane. The approach proposed here can be used to prepare membranes containing primary ions equally distributed through the receptor phase, i.e. membranes that do not require conditioning in primary ions solution and are free from problems related to slow diffusion of primary ions. Thus obtained sensors were characterized with linear responses (also at relatively high activities) and high selectivities, despite considerable reduction of ionophore and ion-exchanger amount introduced to the membrane. To be able to prepare ion-selective membranes using this approach, a method for quantification of ionophore and ion-exchanger introduced into microspheres is required. In this work a novel method utilizing high performance liquid chromatography (HPLC) with DAD or FLD detection is proposed. Incorporation of ionophore and ion-exchanger into the microspheres was achieved either by absorption into ready spheres or in course of photopolymerization of polymeric beads. The obtained results have proven that both procedures led to incorporation of ionophore/ion-exchanger into polymeric spheres, however, the content of the compounds in the spheres post process is different from their ratio in solution from which they had been introduced. These effects need to be considered/compensated while preparing microspheres containing ion-selective membranes. As a model system poly(n-butyl acrylate) spheres, silver selective ionophore and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate were chosen, resulting ultimately in silver-selective electrodes. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Genetic Screening Strategy for Rapid Access to Polyether Ionophore Producers and Products in Actinomycetes ▿ †

    Science.gov (United States)

    Wang, Hao; Liu, Ning; Xi, Lijun; Rong, Xiaoying; Ruan, Jisheng; Huang, Ying

    2011-01-01

    Polyether ionophores are a unique class of polyketides with broad-spectrum activity and outstanding potency for the control of drug-resistant bacteria and parasites, and they are produced exclusively by actinomycetes. A special epoxidase gene encoding a critical tailoring enzyme involved in the biosynthesis of these compounds has been found in all five of the complete gene clusters of polyether ionophores published so far. To detect potential producer strains of these antibiotics, a pair of degenerate primers was designed according to the conserved regions of the five known polyether epoxidases. A total of 44 putative polyether epoxidase gene-positive strains were obtained by the PCR-based screening of 1,068 actinomycetes isolated from eight different habitats and 236 reference strains encompassing eight major families of Actinomycetales. The isolates spanned a wide taxonomic diversity based on 16S rRNA gene analysis, and actinomycetes isolated from acidic soils seemed to be a promising source of polyether ionophores. Four genera were detected to contain putative polyether epoxidases, including Micromonospora, which has not previously been reported to produce polyether ionophores. The designed primers also detected putative epoxidase genes from diverse known producer strains that produce polyether ionophores unrelated to the five published gene clusters. Moreover, phylogenetic and chemical analyses showed a strong correlation between the sequence of polyether epoxidases and the structure of encoded polyethers. Thirteen positive isolates were proven to be polyether ionophore producers as expected, and two new analogues were found. These results demonstrate the feasibility of using this epoxidase gene screening strategy to aid the rapid identification of known products and the discovery of unknown polyethers in actinomycetes. PMID:21421776

  10. Rapid quantification of ionophores in feeds by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Huang, Min; Rumbeiha, Wilson K; Braselton, W Emmett; Johnson, Margaret

    2011-09-01

    Ionophores are widely used in veterinary medicine as coccidiostats and for improving nutrient utilization in livestock production. Because of widespread use, ionophores sometimes cause poisoning in livestock. Quantifying concentration of these compounds in feeds for diagnostic purposes is needed. A method with a single step of solvent extraction was developed for rapid simultaneous quantification of monensin, lasalocid, salinomycin, and narasin in feeds by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The ionophores were extracted using methanol:water (90:10). With the high specificity and high sensitivity of tandem mass spectrometry, the extract was introduced for measurement without further processing. The effect of particle size of feeds on extraction efficiency was also investigated. It was found that feeds passing through a 1-mm filter or sieve show better quantitative extraction. Nigericin was used as internal standard for the measurement. The method was validated by fortification of the selected ionophore compounds in horse feed at different concentrations. The typical recovery rate was 69-122%. Meanwhile, various interlaboratory proficiency test samples of different matrices were also quantified as part of the procedure for method validation. A good agreement was found between results and the suggested values. The method is very sensitive, with detection limits between 0.018 µg/g and 0.056 µg/g for the compounds tested. Results showed that the lower limit of quantification was 0.2 µg/g for the ionophore compounds, which is much lower than the contents of the ionophores in medicated feeds, which is generally approximately 10-100 µg/g feed.

  11. Salinomycin and other ionophores as a new class of antimalarial drugs with transmission-blocking activity.

    Science.gov (United States)

    D'Alessandro, Sarah; Corbett, Yolanda; Ilboudo, Denise P; Misiano, Paola; Dahiya, Nisha; Abay, Solomon M; Habluetzel, Annette; Grande, Romualdo; Gismondo, Maria R; Dechering, Koen J; Koolen, Karin M J; Sauerwein, Robert W; Taramelli, Donatella; Basilico, Nicoletta; Parapini, Silvia

    2015-09-01

    The drug target profile proposed by the Medicines for Malaria Venture for a malaria elimination/eradication policy focuses on molecules active on both asexual and sexual stages of Plasmodium, thus with both curative and transmission-blocking activities. The aim of the present work was to investigate whether the class of monovalent ionophores, which includes drugs used in veterinary medicine and that were recently proposed as human anticancer agents, meets these requirements. The activity of salinomycin, monensin, and nigericin on Plasmodium falciparum asexual and sexual erythrocytic stages and on the development of the Plasmodium berghei and P. falciparum mosquito stages is reported here. Gametocytogenesis of the P. falciparum strain 3D7 was induced in vitro, and gametocytes at stage II and III or stage IV and V of development were treated for different lengths of time with the ionophores and their viability measured with the parasite lactate dehydrogenase (pLDH) assay. The monovalent ionophores efficiently killed both asexual parasites and gametocytes with a nanomolar 50% inhibitory concentration (IC50). Salinomycin showed a fast speed of kill compared to that of standard drugs, and the potency was higher on stage IV and V than on stage II and III gametocytes. The ionophores inhibited ookinete development and subsequent oocyst formation in the mosquito midgut, confirming their transmission-blocking activity. Potential toxicity due to hemolysis was excluded, since only infected and not normal erythrocytes were damaged by ionophores. Our data strongly support the downstream exploration of monovalent ionophores for repositioning as new antimalarial and transmission-blocking leads. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Synthesis and characterization of monoazathiacrown ethers as ionophores for polymeric membrane silver-selective electrodes.

    Science.gov (United States)

    Zhang, Jun; Ding, Jiawang; Yin, Tanji; Hu, Xuefeng; Yu, Shunyang; Qin, Wei

    2010-05-15

    Nine monoazathiacrown ethers have been synthesized and explored as ionophores for polymeric membrane Ag(+)-selective electrodes. Potentiometric responses reveal that the ion-selective electrodes (ISEs) based on 2,2'-thiodiethanethiol derivatives can exhibit excellent selectivities toward Ag(+). The plasticized poly(vinyl chloride) membrane electrode using 22-membered N(2)S(5)-ligand as ionophore has been characterized and its logarithmic selectivity coefficients for Ag(+) over most of the interfering cations have been determined as <-8.0. Under optimal conditions, a lower detection limit of 2.2x10(-10)M can be obtained for the membrane Ag(+)-ISE.

  13. Calcium Carbonate

    Science.gov (United States)

    Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not ... for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve ...

  14. Calcium supplements

    Science.gov (United States)

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

  15. N′, N ″, N‴-tris (2-pyridyloxymethyl) ethane as ionophore in ...

    Indian Academy of Sciences (India)

    N′,N″,N‴ tris(2-pyridyloxymethyl) ethane (TPOME) has been used as an ionophore in a polyvinylchloride (PVC)-based membrane. Membrane electrode with a composition 30:5:62:3 (PVC:TPOME: o-NPOE:NaTPB) exhibits Nernstian response towards Pb(II) ions with a slope of 30mV/decade, over a concentration range ...

  16. Quantification of ionophores in aged poultry litter using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Biswas, Saptashati; McGrath, Joshua M; Sapkota, Amir

    2012-01-01

    Veterinary anticoccidials, biochemically known as ionophores, are widely used in poultry feed at therapeutic levels to treat Coccidiosis and at sub-therapeutic levels for growth- promotion. Commonly used ionophores in the US poultry industry are monensin, salinomycin, lasalocid and narasin. There is an increasing concern regarding the persistence of these anticoccidials in the environment. However, little attention has been directed to methods development for quantitatively measuring ionophores in complex environmental matrices such as poultry litters that are land applied. Here, we describe a rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS)-based method developed for simultaneous quantification of monensin, lasalocid, salinomycin, and narasin in aged poultry litter samples. Results show significant level of monensin (97.8 ± 3.2 μg kg⁻¹), lasalocid (19.2 ± 6.6 μg kg⁻¹), salinomycin (70 ± 2.7 μg kg⁻¹) and narasin (57.3 ± 2.6 μg kg⁻¹) in poultry litter stored for over three years at ionophores may continue to persist in this matrix, raising the possibility of prolonged release into the environment.

  17. Helical peptaibol mimics are better ionophores when racemic than when enantiopure.

    Science.gov (United States)

    Pike, Sarah J; Jones, Jennifer E; Raftery, James; Clayden, Jonathan; Webb, Simon J

    2015-10-07

    Helical peptide foldamers rich in α-aminoisobutyric acid (Aib) act as peptaibol-mimicking ionophores in the phospholipid bilayers of artificial vesicles. Racemic samples of these foldamers are more active than their enantiopure counterparts, which was attributed to differing propensities to form aggregates with crystal-like features in the bilayer.

  18. Non-covalent (iso)guanosine-based ionophores for alkali(ne earth) cations

    NARCIS (Netherlands)

    van Leeuwen, F.W.B.; Davis, Jeffery T.; Davis, J.T.; Verboom, Willem; Reinhoudt, David

    2006-01-01

    Different (iso)guanosine-based self-assembled ionophores give distinctly different results in extraction experiments with alkali(ne earth) cations. A lipophilic guanosine derivative gives good extraction results for K+, Rb+, Ca2+, Sr2+, and Ba2+ and in competition experiments it clearly favors the

  19. Astonishing diversity of natural surfactants: 2. Polyether glycosidic ionophores and macrocyclic glycosides.

    Science.gov (United States)

    Dembitsky, Valery M

    2005-03-01

    Polyether glycosidic ionophores and macrocyclic glycosides are of great interest, especially for the medicinal and pharmaceutical industries. These biologically active natural surfactants are good prospects for the future chemical preparation of compounds useful as antibiotics, anticancer agents, or in industry. More than 300 interesting and unusual natural surfactants are described in this review article, including their chemical structures and biological activities.

  20. Selective 226RA2+ionophores provided by self-assembly of guanosine and isoguanosine deratives

    NARCIS (Netherlands)

    van Leeuwen, F.W.B.; Verboom, Willem; Shi, Xiaodong; Davis, J.T.; Davis, Jeffery T.; Reinhoudt, David

    2004-01-01

    The self-assembled guanosine (G 1)-based hexadecamers and isoguanosine (isoG 2)-based decamers are excellent 226Ra2+ selective ionophores even in the presence of excess alkali (Na+, K+, Rb+, and Cs+) and alkaline earth (Mg2+, Ca2+, Sr2+, and Ba2+) cations over the pH range 3-11. G 1 requires

  1. ethane as ionophore in potentiometric sensor for Pb(II) ions

    Indian Academy of Sciences (India)

    ric titration of Pb(II) ions with standard chromate solution and its determination in real-life samples. Surface morphology of membrane electrode at different stages of its development and use is also discussed. Keywords. PVC; neutral carrier; ionophore; liquid membrane; lead ions; selectivity coefficients; Nernstian response.

  2. Effects of ionophores on Enterococcus faecalis and E. faecium growth in pure and mixed ruminal culture

    Science.gov (United States)

    Enterococcus faecalis and faecium are Gram-positive human pathogens that can live in the gastrointestinal tract of food animals. Vancomycin-resistant enterococci (VRE) are an increasing threat to humans as a nosocomial infection, as well as a reservoir of antibiotic resistance genes. Ionophores ar...

  3. Potentiometric sensors based on fluorous membranes doped with highly selective ionophores for carbonate.

    Science.gov (United States)

    Chen, Li D; Mandal, Debaprasad; Pozzi, Gianluca; Gladysz, John A; Bühlmann, Philippe

    2011-12-28

    Manganese(III) complexes of three fluorophilic salen derivatives were used to prepare ion-selective electrodes (ISEs) with ionophore-doped fluorous sensing membranes. Because of their extremely low polarity and polarizability, fluorous media are not only chemically very inert but also solvate potentially interfering ions poorly, resulting in a much improved discrimination of such ions. Indeed, the new ISEs exhibited selectivities for CO(3)(2-) that exceed those of previously reported ISEs based on nonfluorous membranes by several orders of magnitude. In particular, the interference from chloride and salicylate was reduced by 2 and 6 orders of magnitude, respectively. To achieve this, the selectivities of these ISEs were fine-tuned by addition of noncoordinating hydrophobic ions (i.e., ionic sites) into the sensing membranes. Stability constants of the anion-ionophore complexes were determined from the dependence of the potentiometric selectivities on the charge sign of the ionic sites and the molar ratio of ionic sites and the ionophore. For this purpose, a previously introduced fluorophilic tetraphenylborate and a novel fluorophilic cation with a bis(triphenylphosphoranylidene)ammonium group, (R(f6)(CH(2))(3))(3)PN(+)P(R(f6)(CH(2))(3))(3), were utilized (where R(f6) is C(6)F(13)). The optimum CO(3)(2-) selectivities were found for sensing membranes composed of anionic sites and ionophore in a 1:4 molar ratio, which results in the formation of 2:1 complexes with CO(3)(2-) with stability constants up to 4.1 × 10(15). As predicted by established theory, the site-to-ionophore ratios that provide optimum potentiometric selectivity depend on the stoichiometries of the complexes of both the primary and the interfering ions. However, the ionophores used in this study give examples of charges and stoichiometries previously neither explicitly predicted by theory nor shown by experiment. The exceptional selectivity of fluorous membranes doped with these carbonate ionophores

  4. Stimulation of root elongation and curvature by calcium

    Science.gov (United States)

    Takahashi, H.; Scott, T. K.; Suge, H.

    1992-01-01

    Ca2+ has been proposed to mediate inhibition of root elongation. However, exogenous Ca2+ at 10 or 20 millimolar, applied directly to the root cap, significantly stimulated root elongation in pea (Pisum sativum L.) and corn (Zea mays L.) seedlings. Furthermore, Ca2+ at 1 to 20 millimolar, applied unilaterally to the caps of Alaska pea roots, caused root curvature away from the Ca2+ source, which was caused by an acceleration of elongation growth on the convex side (Ca2+ side) of the roots. Roots of an agravitropic pea mutant, ageotropum, responded to a greater extent. Roots of Merit and Silver Queen corn also responded to Ca2+ in similar ways but required a higher Ca2+ concentration than that of pea roots. Roots of all other cultivars tested (additional four cultivars of pea and one of corn) curved away from the unilateral Ca2+ source as well. The Ca(2+)-stimulated curvature was substantially enhanced by light. A Ca2+ ionophore, A23187, at 20 micromolar or abscisic acid at 0.1 to 100 micromolar partially substituted for the light effect and enhanced the Ca(2+)-stimulated curvature in the dark. Unilateral application of Ca2+ to the elongation zone of intact roots or to the cut end of detipped roots caused either no curvature or very slight curvature toward the Ca2+. Thus, Ca2+ action on root elongation differs depending on its site of application. The stimulatory action of Ca2+ may involve an elevation of cytoplasmic Ca2+ in root cap cells and may partipate in root tropisms.

  5. Impaired cytoplasmic ionized calcium mobilization in inherited platelet secretion defects

    Energy Technology Data Exchange (ETDEWEB)

    Rao, A.K.; Kowalska, M.A.; Disa, J. (Temple Univ. School of Medicine, Philadelphia, PA (USA))

    1989-08-01

    Defects in platelet cytoplasmic Ca++ mobilization have been postulated but not well demonstrated in patients with inherited platelet secretion defects. We describe studies in a 42-year-old white woman, referred for evaluation of easy bruising, and her 23-year-old son. In both subjects, aggregation and {sup 14}C-serotonin secretion responses in platelet-rich plasma (PRP) to adenosine diphosphate (ADP), epinephrine, platelet activating factor (PAF), arachidonic acid (AA), U46619, and ionophore A23187 were markedly impaired. Platelet ADP and adenosine triphosphate (ATP), contents and thromboxane synthesis induced by thrombin and AA were normal. In quin2-loaded platelets, the basal intracellular Ca++ concentration, (Ca++)i, was normal; however, peak (Ca++)i measured in the presence of 1 mmol/L external Ca++ was consistently diminished following activation with ADP (25 mumol/L), PAF (20 mumol/L), collagen (5 micrograms/mL), U46619 (1 mumol/L), and thrombin (0.05 to 0.5 U/mL). In aequorin-loaded platelets, the peak (Ca++)i studied following thrombin (0.05 and 0.5 U/mL) stimulation was diminished. Myosin light chain phosphorylation following thrombin (0.05 to 0.5 U/mL) stimulation was comparable with that in the normal controls, while with ADP (25 mumol/L) it was more strikingly impaired in the propositus. We provide direct evidence that at least in some patients with inherited platelet secretion defects, agonist-induced Ca++ mobilization is impaired. This may be related to defects in phospholipase C activation. These patients provide a unique opportunity to obtain new insights into Ca++ mobilization in platelets.

  6. Determination of regulatory ionophore coccidiostat residues in feedstuffs at carry-over levels by liquid chromatography-mass spectrometry

    National Research Council Canada - National Science Library

    Loredana Annunziata; Pierina Visciano; Arianna Stramenga; Maria Novella Colagrande; Guido Campana; Giampiero Scortichini; Giacomo Migliorati; Dario Compagnone

    2017-01-01

    In this study samples of feedstuffs were collected from different feed mills and animal farms located in central Italy and analyzed for ionophore coccidiostat residues at carry-over levels by liquid...

  7. A new approach to the analysis of nicarbazin and ionophores in eggs by HPLC/MS/MS.

    Science.gov (United States)

    Dmitrovic, Jasna; Durden, David A

    2011-01-01

    An HPLC/MS/MS method has been developed and validated for the quantification and confirmation of nicarbazin and ionophores (lasalocid, monensin, salinomycin, and narasin) in eggs. Nicarbazin is determined in the negative electrospray mode with a basic mobile phase that supports creation of negative ions. Consequently, our ability to maintain instrument sensitivity over time has significantly improved. The analysis of the ionophores is done in the positive electrospray mode using ammonium buffer for HPLC separation. Monitoring ammonium adduct parent ions resulted in enhanced sensitivity and better reproducibility of the ionophore analysis. The validation of this improved HPLC/MS/MS method for the detection of nicarbazin and the ionophores demonstrated excellent precision of below 10% RSD and lower LOD values (microg/kg) for nicarbazin (0.018), lasalocid (0.015), monensin (0.015), salinomycin (0.033), and narasin (0.039).

  8. Immobilization of Ionophore and Surface Characterization Studies of the Titanium(III Ion in a PVC-Membrane Sensor

    Directory of Open Access Journals (Sweden)

    Majid Rezayi

    2012-06-01

    Full Text Available Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride (PVC matrices, and these were examined to determine Ti(III selectivity. To predict the selectivity of Ti(III, a PVC membrane was used to investigate the binding of Ti(III to c-methylcalix[4]resorcinarene (CMCR. The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl borate (NaTFPB as a lipophilic ionic additive, and dioctylphthalate (DOP as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs. The strengths of the ion-ionophore (CMCR-Ti(OH(OH252+ interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT–IR, scanning electron microscopy (SEM and and X-ray diffraction (XRD.

  9. Effect of ionophores and pH on growth of Streptococcus bovis in batch and continuous culture.

    Science.gov (United States)

    Chow, J M; Russell, J B

    1990-01-01

    Batch cultures (pH 6.7) of Streptococcus bovis JB1 were severely inhibited by 1.25 and 5 microM lasalocid and monensin, respectively, even though large amounts of glucose remained in the medium. However, continuous cultures tolerated as much as 10 and 20 microM, respectively, and used virtually all of the glucose. Although continuous cultures grew with high concentrations of ionophore, the yield of bacterial protein decreased approximately 10-fold. When pH was decreased from 6.7 to 5.7, the potency of both ionophores increased, but lasalocid always caused a larger decrease in yield. The increased activity of lasalocid at pH 5.7 could largely be explained by an increased binding of the ionophore to the cell membrane. Because monensin did not show an increased binding at low pH, some other factor (e.g., ion turnover) must have been influencing its activity. There was a linear increase in lasalocid binding as the concentration increased, but monensin binding increased markedly at high concentrations. Based on the observations that (i) S. bovis cells bound significant amounts of ionophore (the ratio of ionophore to cell material was more important than the absolute concentration), (ii) batch cultures responded differently from continuous cultures, and (iii) pH can have a marked effect on ionophore activity, it appears that the term "minimum inhibitory concentration" may not provide an accurate assessment of microbial growth inhibition in vivo. PMID:2383003

  10. Activity of Natural Polyether Ionophores: Monensin and Salinomycin against Clinical Staphylococcus epidermidis Strains.

    Science.gov (United States)

    Stefańska, Joann; Stępień, Karolina; Huczyński, Adam; Tyski, Stefan

    2015-01-01

    Staphylococcus epidermidis, a coagulase-negative Staphylococcus, is the most important pathogen responsible for chronic nosocomial infections. These bacteria produce extracellular slime and form biofilms on various biotic and abiotic surfaces. Bacterial biofilms are very resistant to standard antimicrobial therapy and difficult to eradicate, so it is important to search for new more effective anti-biofilm agents, for example in the group of natural substances. The aim of the study was to examine the activity of two ionophores-salinomycin and monensin against clinical S. epidermidis strains, using MIC/MBC method and biofilm formation inhibition assay. Bacterial strains were tested also for slime production using Congo Red Agar. Both tested ionophore antibiotics showed the highest activity against planktonic bacteria of clinical as well as standard S. epidermidis strains and effectively inhibited the formation of bacterial biofilm.

  11. Benzodipyrrole derivates as new ionophores for anion-selective electrodes: improving potentiometric selectivity towards divalent anions.

    Science.gov (United States)

    Cuartero, M; Ortuño, J A; García, M S; Sánchez, G; Más-Montoya, M; Curiel, D

    2011-09-30

    Two open substituted benzodipyrroles were tested as hydrogen-bond-forming anion ionophores for the development of anion-selective electrodes. These compounds were incorporated in plasticized polymeric membranes with different plasticizers, using different membrane compositions to explore their response towards several anions. The electrodes constructed with membranes containing 2-nitrophenyl octyl ether and a 0.5 molar ratio ionic additive/ionophore showed pronounced anti-Hofmeister behaviour, providing a significantly enhanced response towards the divalent anions sulfate, sulfite, thiosulfate and oxalate. The selected electrodes were also evaluated in terms of detection limits and selectivity. (1)H NMR experiments were carried out in an attempt to explain some aspects of the behaviour observed. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Carboxylic ionophores enhance the cytotoxic potency of ligand- and antibody-delivered ricin A chain

    Science.gov (United States)

    1984-01-01

    The highly selective cytotoxicity of site-directed ricin A chain conjugates can be potentiated by membrane-active carboxylic ionophores. The combined use of the two agents results in much faster inactivation of ribosomes and subsequent cell death and lysis. The potency of A chain cytotoxins is correspondingly increased by several orders of magnitude and cells that sparsely express the target antigen or receptor can be killed. PMID:6090575

  13. Enhancement of hydrogen peroxide formation by protophores and ionophores in antimycin-supplemented mitochondria

    Science.gov (United States)

    Cadenas, Enrique; Boveris, Alberto

    1980-01-01

    Rat and pigeon heart mitochondria supplemented with antimycin produce 0.3–1.0nmol of H2O2/min per mg of protein. These rates are stimulated up to 13-fold by addition of protophores (carbonyl cyanide p-trifluoromethoxyphenylhydrazone, carbonyl cyanide m-chloromethoxyphenylhydrazone and pentachlorophenol). Ionophores, such as valinomycin and gramicidin, and Ca2+ also markedly stimulated H2O2 production by rat heart mitochondria. The enhancement of H2O2 generation in antimycin-supplemented mitochondria and the increased O2 uptake of the State 4-to-State 3 transition showed similar protophore, ionophore and Ca2+ concentration dependencies. Thenoyltrifluoroacetone and N-bromosuccinimide, which inhibit succinate–ubiquinone reductase activity, also decreased mitochondrial H2O2 production. Addition of cyanide to antimycin-supplemented beef heart submitochondrial particles inhibited the generation of O2−, the precursor of mitochondrial H2O2. This effect was parallel to the increase in cytochrome c reduction and it is interpreted as indicating the necessity of cytochrome c13+ to oxidize ubiquinol to ubisemiquinone, whose autoxidation yields O2−. The effect of protophores, ionophores and Ca2+ is analysed in relation to the propositions of a cyclic mechanism for the interaction of ubiquinone with succinate dehydrogenase and cytochromes b and c1 [Wikstrom & Berden (1972) Biochim. Biophys. Acta 283, 403–420; Mitchell (1976) J. Theor. Biol. 62, 337–367]. A collapse in membrane potential, increasing the rate of ubisemiquinone formation and O2− production, is proposed as the molecular mechanism for the enhancement of H2O2 formation rates observed on addition of protophores, ionophores and Ca2+. PMID:7406888

  14. Crown bridged thiacalix[4]arenes as cesium-selective ionophores in solvent polymeric membrane electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Bereczki, Robert [Technical Analytical Research Group of the Hungarian Academy of Sciences, Department of General and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellert ter 4, H-1111 Budapest (Hungary); Csokai, Viktor [Department of Organic Chemical Technology, Budapest University of Technology and Economics, Muegyetem rkp.3, H-1111 Budapest (Hungary); Gruen, Alajos [Department of Organic Chemical Technology, Budapest University of Technology and Economics, Muegyetem rkp.3, H-1111 Budapest (Hungary); Bitter, Istvan [Department of Organic Chemical Technology, Budapest University of Technology and Economics, Muegyetem rkp.3, H-1111 Budapest (Hungary); Toth, Klara [Technical Analytical Research Group of the Hungarian Academy of Sciences, Department of General and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellert ter 4, H-1111 Budapest (Hungary)]. E-mail: ktoth@mail.bme.hu

    2006-05-31

    Novel 1,3-alternate thiacalix[4]mono- and biscrown-6 ethers were studied as ionophores in poly(vinyl chloride) membrane electrodes. Their selectivity behavior was characterized with respect to large number of cations, including potential interferents in environmental samples, and the membrane composition was optimized for cesium ion response. Among the ionophores, 1,3-alternate thiacalix[4]mono(crown-6) ether showed, especially high selectivity for cesium over other alkali-metal ions. Transition and heavy metal ions did not interfere seriously with the electrode response, which indicates that the bridging sulfur atoms do not take part in the ion recognition process. The potentiometric cesium responses of all electrodes involved in this study were found close to Nernstian and the detection limits were lower than 10{sup -7} M. The Cs{sup +}/Na{sup +} selectivity of the different ionophore-based sensors and the solvent extraction ability of the ligands were interpreted based on the respective constants of complex formation.

  15. Selective 226Ra2+ ionophores provided by self-assembly of guanosine and isoguanosine derivatives.

    Science.gov (United States)

    van Leeuwen, Fijs W B; Verboom, Willem; Shi, Xiaodong; Davis, Jeffery T; Reinhoudt, David N

    2004-12-22

    The self-assembled guanosine (G 1)-based hexadecamers and isoguanosine (isoG 2)-based decamers are excellent 226Ra2+ selective ionophores even in the presence of excess alkali (Na+, K+, Rb+, and Cs+) and alkaline earth (Mg2+, Ca2+, Sr2+, and Ba2+) cations over the pH range 3-11. G 1 requires additional picrate anions to provide a neutral assembly, whereas the isoG 2 assembly extracts 226Ra2+ cations without any such additives. Both G 1-picrate and isoG 2 assemblies show 226Ra2+ extraction even at a 0.35 x 10(6) fold excess of Na+, K+, Rb+, Cs+, Mg2+, or Ca2+ (10(-2) M) to 226Ra2+ (2.9 x 10(-8) M) and at a 100-fold salt to ionophore excess. In the case of the G 1-picrate assembly, more competition was observed from Sr2+ and Ba2+, as extraction of 226Ra2+ ceased at an M2+/226Ra2+ ratio of 10(6) and 10(4), respectively. With the isoG 2 assembly, 226Ra2+ extraction also occurred at a Sr2+/226Ra2+ ratio of 10(6) but ceased at a 10(6) excess of Ba2+. The results clearly demonstrate the power of molecular self-assembly for the construction of highly selective ionophores.

  16. Effects of ionophores on liver CYP1A and 3A in male broilers.

    Science.gov (United States)

    Zhang, L L; Zhang, J R; Yu, Z G; Zhao, J; Mo, F; Jiang, S X

    2010-12-01

    The effects of ionophore antibiotics on the enzyme activity, protein and mRNA expression levels of cytochrome P450 (CYP) isoenzymes were investigated in liver from male Arbor Acres (AA) broiler chicks. Monensin, salinomycin and maduramycin at the dosage of 120, 60, and 5 mg/kg were administered in feed for 14 days. CYP1A and CYP3A activities were quantitated using cocktail probe drugs and a high performance liquid chromatographic (HPLC) assay at the 15th day; the protein expressions of CYP1A and CYP3A were detected by Western blot. CYP1A4, CYP1A5 and CYP3A37 mRNA levels were detected by real-time polymerase chain reaction (real-time PCR). Monensin, salinomycin and maduramycin had no effect on caffeine metabolism, protein expression and mRNA expression, but did induce dapsone metabolism, increasing CYP3A protein expression. However, there was no change in CYP3A37 mRNA expression as compared with the control group. It is suggested that ionophore antibiotics may have an induction effect on CYP3A expression and enzyme activity and that such effect might be related to the posttranscriptional regulation of its protein expression. Consideration of the enhanced metabolism of other drugs used simultaneously with ionophores is therefore recommended. © 2010 Blackwell Publishing Ltd.

  17. Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction.

    Science.gov (United States)

    Bak, Søren Alex; Hansen, Martin; Pedersen, Kenneth Munk; Halling-Sørensen, Bent; Björklund, Erland

    2013-09-13

    A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid chromatography coupled to tandem mass spectrometry applying electrospray ionisation for detection. The samples were freeze-dried prior to extraction. The absolute recoveries for soil and sediment ranged from 71 to 123% (relative standard deviation (RSDs) below 16%) and in the range 94-133% (RSDs 9-35%) for poultry manure. The final method allowed for the detection of four ionophores down to a few hundred ngkg(-1) in natural solid matrices with limit of quantifications (LOQs) being 0.96, 0.87, 0.98, and 0.64μgkg(-1) in soil for lasalocid, monensin, salinomycin, and narasin, respectively. Corresponding LOQs in sediment were 1.28, 1.34, 1.39, and 0.78μgkg(-1) for the respective ionophores, while in manure the LOQs were 0.98, 1.01, 1.45, and 1.01μgkg(-1). Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Effect of three polyether ionophores on pharmacokinetics of florfenicol in male broilers.

    Science.gov (United States)

    Wang, G-Y; Tu, P; Chen, X; Guo, Y-G; Jiang, S-X

    2013-10-01

    Drug-drug interactions (DDIs) may adversely affect the prevention and cure of diseases. The effects of three polyether ionophore antibiotics, salinomycin (SAL), monensin (MON), and maduramycin (MAD) on the pharmacokinetics of florfenicol (FFC) were investigated in broilers. The chickens were fed rations with or without SAL (60 mg/kg feeds), MON (120 mg/kg feeds), or MAD (5 mg/kg feeds) for 14 consecutive days. FFC was given to the chickens either intravenously (i.v.) or orally (p.o.) at a single dose of 30 mg/kg body weight. Blood samples were taken from each chicken at 0-24 h postadministration of FFC. The plasma concentration of FFC was detected by high-performance liquid chromatography. The plasma concentration of FFC decreased with i.v. or p.o. co-administration of SAL, MON, or MAD in broilers, implying occurrence of DDIs during the co-administration of FFC with these ionophores. Our findings suggest that more attention should be given to the use of FFC to treat bacterial infections in chickens supplemented with polyether ionophore antibiotics. © 2012 John Wiley & Sons Ltd.

  19. Ion transport through lipid bilayers by synthetic ionophores: modulation of activity and selectivity.

    Science.gov (United States)

    De Riccardis, Francesco; Izzo, Irene; Montesarchio, Daniela; Tecilla, Paolo

    2013-12-17

    The ion-coupled processes that occur in the plasma membrane regulate the cell machineries in all the living organisms. The details of the chemical events that allow ion transport in biological systems remain elusive. However, investigations of the structure and function of natural and artificial transporters has led to increasing insights about the conductance mechanisms. Since the publication of the first successful artificial system by Tabushi and co-workers in 1982, synthetic chemists have designed and constructed a variety of chemically diverse and effective low molecular weight ionophores. Despite their relative structural simplicity, ionophores must satisfy several requirements. They must partition in the membrane, interact specifically with ions, shield them from the hydrocarbon core of the phospholipid bilayer, and transport ions from one side of the membrane to the other. All these attributes require amphipathic molecules in which the polar donor set used for ion recognition (usually oxygens for cations and hydrogen bond donors for anions) is arranged on a lipophilic organic scaffold. Playing with these two structural motifs, donor atoms and scaffolds, researchers have constructed a variety of different ionophores, and we describe a subset of interesting examples in this Account. Despite the ample structural diversity, structure/activity relationships studies reveal common features. Even when they include different hydrophilic moieties (oxyethylene chains, free hydroxyl, etc.) and scaffolds (steroid derivatives, neutral or polar macrocycles, etc.), amphipathic molecules, that cannot span the entire phospholipid bilayer, generate defects in the contact zone between the ionophore and the lipids and increase the permeability in the bulk membrane. Therefore, topologically complex structures that span the entire membrane are needed to elicit channel-like and ion selective behaviors. In particular the alternate-calix[4]arene macrocycle proved to be a versatile

  20. Effect of aspirin on the metabolism of exogenous arachidonic acid in human polymorphonuclear leukocytes

    Energy Technology Data Exchange (ETDEWEB)

    Punnonen, K.; Uotila, P.

    1984-08-01

    When human polymorphonuclear leukocytes (PMNL) were incubated with exogenous /sup 14/C-arachidonic acid (/sup 14/C-AA), both lipoxygenase and cyclo-oxygenase metabolites were detected. The amount of the 5-lipoxygenase metabolites formed, including 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), was small. The amount of other mono-HETE's (migrating in the vicinity of 12-HETE) was greater, but this was obviously mainly due to the small amount of contaminating platelets. In the presence of calcium ionophore A23187 the rate of formation of 5-HETE was increased, but the formation of other metabolites remained unchanged. When PMNL were incubated with aspirin in the presence of A23187 the formation of the cyclo-oxygenase products was decreased but that of 5-HETE was unchanged. The present study indicates that the calcium ionophore A23187 stimulates specifically the 5-lipoxygenase in human PMNL and that aspirin has no effect on the formation of the 5-lipoxygenase metabolites of arachidonic acid in human PMNL.

  1. Fluorous polymeric membranes for ionophore-based ion-selective potentiometry: how inert is Teflon AF?

    Science.gov (United States)

    Lai, Chun-Ze; Koseoglu, Secil S; Lugert, Elizabeth C; Boswell, Paul G; Rábai, József; Lodge, Timothy P; Bühlmann, Philippe

    2009-02-04

    Fluorous media are the least polar and polarizable condensed phases known. Their use as membrane materials considerably increases the selectivity and robustness of ion-selective electrodes (ISEs). In this research, a fluorous amorphous perfluoropolymer was used for the first time as a matrix for an ISE membrane. Electrodes for pH measurements with membranes composed of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole]-co-poly(tetrafluoroethylene) (87% dioxole monomer content; known as Teflon AF2400) as polymer matrix, a linear perfluorooligoether as plasticizer, sodium tetrakis[3,5-bis(perfluorohexyl)phenyl]borate providing for ionic sites, and bis[(perfluorooctyl)propyl]-2,2,2-trifluoroethylamine as H+ ionophore were investigated. All electrodes had excellent potentiometric selectivities, showed Nernstian responses to H+ over a wide pH range, exhibited enhanced mechanical stability, and maintained their selectivity over at least 4 weeks. For membranes of low ionophore concentration, the polymer affected the sensor selectivity noticeably at polymer concentrations exceeding 15%. Also, the membrane resistance increased quite strongly at high polymer concentrations, which cannot be explained by the Mackie-Meares obstruction model. The selectivities and resistances depend on the polymer concentration because of a functional group associated with Teflon AF2400, with a concentration of one functional group per 854 monomer units of the polymer. In the fluorous environment of these membranes, this functional group binds to Na+, K+, Ca2+, and the unprotonated ionophore with binding constants of 10(3.5), 10(1.8), 10(6.8), and 10(4.4) M(-1), respectively. Potentiometric and spectroscopic evidence indicates that these functional groups are COOH groups formed by the hydrolysis of carboxylic acid fluoride (COF) groups originally present in Teflon AF2400. The use of higher ionophore concentrations removes the undesirable effect of these COOH groups almost completely

  2. Fluorous Polymeric Membranes for Ionophore-Based Ion-Selective Potentiometry: How Inert is Teflon AF?

    Science.gov (United States)

    Lai, Chun-Ze; Koseoglu, Secil S.; Lugert, Elizabeth C.; Boswell, Paul G.; Rábai, József; Lodge, Timothy P.; Bühlmann, Philippe

    2011-01-01

    Fluorous media are the least polar and polarizable condensed phases known. Their use as membrane materials considerably increases the selectivity and robustness of ion-selective electrodes (ISEs). In this research, a fluorous amorphous perfluoropolymer was used for the first time as a matrix for an ISE membrane. Electrodes for pH measurements with membranes composed of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole]-co-poly(tetrafluoroethylene) (87% dioxole monomer content; known as Teflon AF2400) as polymer matrix, a linear perfluorooligoether as plasticizer, sodium tetrakis[3,5-bis(perfluorohexyl)phenyl]borate providing for ionic sites, and bis[(perfluorooctyl)propyl]-2,2,2-trifluoroethylamine as H+-ionophore were investigated. All electrodes had excellent potentiometric selectivities, showed Nernstian responses to H+ over a wide pH range, exhibited enhanced mechanical stability and maintained their selectivity over at least four weeks. For membranes of low ionophore concentration, the polymer affected the sensor selectivity noticeably at polymer concentrations exceeding 15%. Also, the membrane resistance increased quite strongly at high polymer concentrations, which cannot be explained by the Mackie–Meares obstruction model. The selectivities and resistances depend on the polymer concentration because of a functional group associated with Teflon AF2400, with a concentration of one functional group per 854 monomer units of the polymer. In the fluorous environment of these membranes, this functional group binds to Na+, K+, Ca2+, and the unprotonated ionophore with binding constants of 103.5, 101.8, 106.8 and 104.4 M−1, respectively. Potentiometric and spectroscopic evidence indicates that these functional groups are COOH groups formed by the hydrolysis of carboxylic acid fluoride (COF) groups originally present in Teflon AF2400. The use of higher ionophore concentrations removes the undesirable effect of these COOH groups almost completely

  3. Antidepressants and seizure-interactions at the GABA-receptor chloride-ionophore complex

    Energy Technology Data Exchange (ETDEWEB)

    Malatynska, E.; Knapp, R.J.; Ikeda, M.; Yamamura, H.I.

    1988-01-01

    Convulsive seizures are a potential side effect of antidepressant drug treatment and can be produced by all classes of antidepressants. It is also know that some convulsant and anticonvulsant drug actions are mediated by the GABA-receptor chloride-ionophore complex. Drugs acting at this complex appear to induce convulsions by inhibiting chloride conductance through the associated chloride channel. Using the method of GABA-stimulated /sup 36/Cl-uptake by rat cerebral cortical vesicles, we show that some antidepressant drugs can inhibit the GABA-receptor chloride uptake, and that the degree of chloride channel inhibition by these drugs correlates with the frequency of convulsive seizures induced by them.

  4. Effect of articaine on calcium transport in sarcoplasmic reticulum membranes isolated from medial pterygoid muscle.

    Science.gov (United States)

    Sánchez, Gabriel A; Di Croce, Daniel E; Richard, Susana B; Takara, Delia

    2012-01-01

    Local anesthetics used in dentistry have myotoxic effects. Articaine, also known as carticaine, is one of the local anesthetics most widely used in clinical dentistry. The aim of this work was to describe its effect on the sarcoplasmic reticulum Ca-ATPase isolated from medial pterygoid muscle. Ca-ATPase enzymatic activity was determined by a colorimetric method and ATP-dependent calcium uptake with a radioisotopic technique. Articaine inhibited both Ca-ATPase activity and calcium uptake in a concentration-dependent manner. Both inhibitory effects became evident at articaine concentrations lower than those employed in clinical dentistry. Half-maximal inhibitory concentrations (K) were 15.1 +/- 1.8 mM (n = 6) and 25.2 +/- 1.6 mM (n = 6) for enzymatic activity and calcium uptake, respectively. Preincubation of sarcoplasmic reticulum membranes with articaine enhanced Ca-ATPase activity in the absence of calcium ionophore, suggesting an ionophoric-like effect of the local anesthetic. We conclude that the inhibitory effect of articaine on the sarcoplasmic reticulum Ca-ATPase isolated from medial pterygoid muscle is due to a direct interaction of the anesthetic with the enzyme and to the increased membrane permeability to calcium induced by this drug.

  5. Zirconium(IV)-salophens as fluoride-selective ionophores in polymeric membrane electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gorski, Lukasz [Warsaw University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, Noakowskiego 3, 00-664 Warsaw (Poland); Saniewska, Agnieszka [Warsaw University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, Noakowskiego 3, 00-664 Warsaw (Poland); Parzuchowski, PaweI [Warsaw University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, Noakowskiego 3, 00-664 Warsaw (Poland); Meyerhoff, Mark E. [Department of Chemistry, University of Michigan, Ann Arbor, MI 48109 (United States); Malinowska, Elzbieta [Warsaw University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, Noakowskiego 3, 00-664 Warsaw (Poland)]. E-mail: ejmal@ch.pw.edu.pl

    2005-10-17

    The feasibility of using Zr(IV)-salophens as ionophores to prepare anion-selective polymeric membrane electrodes is examined. It is shown that electrodes formulated with these compounds exhibit greatly enhanced selectivity towards fluoride anion (as compared to a classical quaternary ammonium anion-exchanger) when introduced into plasticized PVC films containing lipophilic anionic site additives. Electrodes constructed with optimal membrane compositions exhibit the following selectivity pattern: F{sup -} > ClO{sub 4} {sup -} > SCN{sup -} > NO{sub 3} {sup -} > Br{sup -} > Cl{sup -}. For these electrodes, near-Nernstian and rapid potentiometric fluoride responses are observed. It is shown that the optimal response to fluoride occurs when the sample solution is buffered in the range of pH 4.5-6.0. At present, the response lifetime of the proposed electrodes is limited to 14 days due to fast deterioration of fluoride response with time. This phenomenon is ascribed to the decomposition of the ionophore within the polymeric membrane phase of the electrode in contact with the aqueous test solution.

  6. Combined use of ionophore and virginiamycin for finishing Nellore steers fed high concentrate diets

    Directory of Open Access Journals (Sweden)

    Amoracyr José Costa Nuñez

    2013-08-01

    Full Text Available Zebu cattle fed high concentrate diets may present inconsistent performance due to the occurrence of metabolic disorders, like acidosis. The isolated use of ionophores and virginiamycin in high grain diets can improve animal performance and reduce the incidence of such disorders, but recent studies suggested that their combination may have an additive effect. Thus, 72 Nellore steers, 389 ± 15 kg initial body weight (BW, were confined and fed for 79 days to evaluate the combination of virginiamycin and salinomycin on performance and carcass traits. Animals were allocated to a randomized complete block design by BW, in a 2 × 2 factorial arrangement of treatments, with two concentrate levels (73 and 91 % and two virginiamycin levels (0 and 15 mg kg-1, and salinomycin (13 mg kg-1 included in all diets. The interaction was not significant (p > 0.05. Dry matter intake (DMI, average daily gain (ADG, gain-to-feed ratio (G:F, starch consumed, and fecal starch content were higher (p 0.05 between treatments. Starch consumed and estimated dietary net energy for maintenance (NEm and gain (NEg were higher (p < 0.05 for virginiamycin-treated animals, with no substantial effects on carcass traits. The inclusion of virginiamycin in finishing diets containing salinomycin reduced DMI while maintaining ADG and improving NEm and NEg, suggesting an additive effect of virginiamycin and ionophores, but without affecting carcass quality.

  7. Fluorescent iminodiacetamide derivatives as potential ionophores for optical zinc ion-selective sensors.

    Science.gov (United States)

    Urbanová, Nikoleta; Kádár, Mihály; Tóth, Klára; Bogáti, Botond; Andruch, Vasil; Bitter, István

    2008-06-01

    Fluorescent sensor molecules were synthesized by conjugation of iminodiacetamide derivatives with fluorescent moieties of different structures and their UV-visible and fluorescent properties were characterized in acetonitrile solvent. The fluorescent measurements revealed that the N-(2-naphthyl) and N-phenyl derivatives exhibit a distinct zinc ion-selectivity over alkali and alkaline earth metal ions, while N-(anthrylmethyl) and N-(3-methoxyphenyl) derivatives do not possess any ion-selectivities. In contrast to the fluorescent measurements, all ligands show Zn(2+) selectivity over Ca(2+) and Mg(2+) ions in plasticized PVC membranes using potentiometric signal transduction. This observation found for N-(anthrylmethyl) and N-(3-methoxyphenyl) derivatives can be ascribed to the more hindered interaction between the signalling group of the ionophore and the central metal ion in PVC membranes than in acetonitrile solution upon complexation. From the fluorescent measurements it can also be concluded that the ligands with metal ions form complexes mainly with 2:1 stoichiometry (L(2)M). On complex formation a considerable decrease in the fluorescent intensity was observed for all ligands except the N-(anthrylmethyl) derivative, where a 25 - 30 fold fluorescence enhancement was found, which is explained by the photoinduced electron transfer (PET) mechanism. All ionophores exhibited serious hydrogen ion interference, therefore complexation-induced spectral changes were measured in aprotic acetonitrile solution.

  8. Total digestibility and in situ degradability of bulky diets with the inclusion of ionophores or probiotics for cattle and buffaloes

    Directory of Open Access Journals (Sweden)

    Lúcia Maria Zeoula

    2014-09-01

    Full Text Available The effects of ionophores (monensin and probiotic (Saccharomyces cerevisiae + selenium + chromium in diets with 80% forage were evaluated on the digestibility of nutrients. Three buffaloes, Murrah (Bubalus bubalis and three cattle, Holstein (Bos taurus, with an average weight of 520 ± 30 kg and 480 ± 182 kg, respectively, with rumen cannula, over experimental design with two 3 x 3 Latin squares in a 3 x 2 factorial arrangement, with the absence or presence of additives: ionophore or probiotic and two species, were used. The internal flow indicator of fecal dry matter (DM was the acid insoluble ash. DM, crude protein (CP and neutral detergent fiber (NDF ruminal degradability of Tifton 85 hay was conducted for cattle and buffaloes. A diet containing probiotics had higher dry matter and organic matter digestibility in buffalo and cattle, indicating a good performance in bulky diets. The potential and effective dry matter degradability in diet with probiotic in buffaloes, were smaller than diet with ionophore, suggesting that there was a better digestion of nutrients in the intestine of these animals. The potential and effective degradability of neutral detergent fiber and crude protein in the diet containing ionophores were superior than diet containing probiotic. Buffaloes showed higher capacity of dry matter and fiber digestion than cattle.

  9. Potentiation by metal ions of the efficacy of the ionophores, monensin and tetronasin, towards four species of ruminal bacteria.

    Science.gov (United States)

    Newbold, C James; Wallace, Robert John; Walker-Bax, Nicola D

    2013-01-01

    Concentrations of Na(+), K(+) and Ca(2+) in the growth medium were varied within limits normally found in vivo to determine how cation concentrations affect the sensitivity of ruminal bacteria to the ionophores, monensin (a Na(+)/H(+) and K(+)/H(+) exchanger) and tetronasin (Ca(2+)/H(+)). High [Na(+)] (172 mM cf. 137 mM in control medium) enhanced the efficacy of monensin towards Eubacterium ruminantium 2388, Streptococcus bovis C277, Lactobacillus casei LB17 and Prevotella albensis M384. High [K(+)] (35 mM cf. 19 mM) alone caused a decreased potency of both ionophores, except with L. casei. Added Ca(2+) (7.4 cf. 2.8 mM) increased the potency of tetronasin when [Na(+)] was low. High [Na(+)] alone also potentiated the efficacy of tetronasin. Monensin caused intracellular [Na(+)] and [K(+)] to be decreased in the most sensitive of these organisms, E. ruminantium, whereas only intracellular [Ca(2+)] fell with tetronasin. The changes were small; however, Δp fell by only 20 mV after 2 h when ionophores caused immediate cessation of growth. ATP concentrations fell by 77% and 75% with monensin and tetronasin, respectively. Thus, altering cation concentrations might be used to potentiate the efficacy of ionophores, by increasing the rate of energy expenditure to maintain ionic homoeostasis in sensitive bacteria. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  10. Inhibition of Cryptosporidium parvum in neonatal Hsd:(ICR)BR Swiss miceby polyether ionophores and aromatic amidines.

    Science.gov (United States)

    Blagburn, B L; Sundermann, C A; Lindsay, D S; Hall, J E; Tidwell, R R

    1991-01-01

    Cryptosporidicidal effects of two polyether ionophores (maduramicin and alborixin), a fluorinated 4-quinolone (enrofloxacin), and three analogs of pentamidine were evaluated in a suckling mouse bioassay. Treatment with all compounds except enrofloxacin and one of the pentamidine analogs [1,3-di(4-imidazolinophenoxy)propane] resulted in significant (P less than 0.05) reductions in oocyst excretion. PMID:1929322

  11. Polymeric membrane electrodes with high nitrite selectivity based on rhodium(III) porphyrins and salophens as ionophores.

    Science.gov (United States)

    Pietrzak, Mariusz; Meyerhoff, Mark E

    2009-05-01

    Several porphyrin and salophen complexes with Rh(III) are examined as ionophores to prepare nitrite selective polymeric membrane electrodes. All ionophores tested exhibit preferred selectivity toward nitrite anion. Enhanced potentiometric nitrite selectivity is observed in the presence of either lipophilic anionic as well as cationic sites within the membranes, suggesting that the ionophores can function via either a charged or a neutral carrier response mechanism. Among a range of complexes and membrane formulations examined, optimal nitrite selectivity and reversible response down to 5 x 10(-6) M is achieved using Rh(III)-tetra(t-butylphenylporphyrin) as the ionophore in the presence of lipophilic cationic sites in plasticized poly(vinyl chloride) membrane. Response times are substantially longer than typical membrane electrodes apparently because of a slow nitrite ligation reaction with Rh(III); however, a significant improvement in dynamic EMF response can be realized by optimizing the membrane formulation and increasing the temperature. The selectivity observed with these membranes is greater than the best nitrite selective electrodes reported to date in the literature based on lipophilic Co(III)-corrin complexes, allowing the new nitrite electrodes to be utilized to determine the level of nitrite in meats with good correlation to the colorimetric Griess assay method.

  12. Influence of Ionophore Supplementation on Growth Performance, Dietary Energetics and Carcass Characteristics in Finishing Cattle during Period of Heat Stress.

    Science.gov (United States)

    Barreras, A; Castro-Pérez, B I; López-Soto, M A; Torrentera, N G; Montaño, M F; Estrada-Angulo, A; Ríos, F G; Dávila-Ramos, H; Plascencia, A; Zinn, R A

    2013-11-01

    Forty-eight crossbred heifers (378.1±18 kg) were used in a 56-d feeding trial (four pens per treatment in a randomised complete block design) to evaluate the influence of ionophore supplementation on growth performance, dietary energetics and carcass characteristics in finishing cattle during a period of heat stress. Heifers were fed a diet based on steam-flaked corn (2.22 Mcal NEm/kg) with and without an ionophore. Treatments were: i) control, no ionophore; ii) 30 mg/kg monensin sodium (RUM30); iii) 20 mg/kg lasalocid sodium (BOV20), and iv) 30 mg/kg lasalocid sodium (BOV30). Both dry matter intake (DMI) and climatic variables were measured daily and the temperature humidity index (THI) was estimated. The maximum THI during the study averaged 93, while the minimum was 70 (THI average = 79.2±2.3). Compared to controls, monensin supplementation did not influence average daily gain, the estimated NE value of the diet, or observed-to-expected DMI, but tended (p = 0.07) to increase (4.8%) gain to feed. Compared to controls, the group fed BOV30 increased (p≤0.03) daily gain (11.8%), gain to feed (8.3%), net energy of the diet (5%), and observed-to-expected DMI (5.2%). Daily weight gain was greater (7.6%, p = 0.05) for heifers fed BOV30 than for heifers fed MON30. Otherwise, differences between the two treatments in DMI, gain to feed, and dietary NE were not statistically significant (p>0.11). Plotting weekly intakes versus THI, observed intake of controls was greater (p0.05) in the ionophores group (CV = 1.7%) than in the control group (CV = 4.5%). Inclusion of ionophores in the diet resulted in relatively minor changes in carcass characteristics. It is concluded that ionophore supplementation did not exacerbate the decline of DM intake in heat-stressed cattle fed a high-energy finishing diet; on the contrary, it stabilised feed intake and favoured feed efficiency. Ionophore supplementation reduced estimated maintenance coefficients around 10% in finishing cattle

  13. Influence of Ionophore Supplementation on Growth Performance, Dietary Energetics and Carcass Characteristics in Finishing Cattle during Period of Heat Stress

    Directory of Open Access Journals (Sweden)

    A. Barreras

    2013-11-01

    Full Text Available Forty-eight crossbred heifers (378.1±18 kg were used in a 56-d feeding trial (four pens per treatment in a randomised complete block design to evaluate the influence of ionophore supplementation on growth performance, dietary energetics and carcass characteristics in finishing cattle during a period of heat stress. Heifers were fed a diet based on steam-flaked corn (2.22 Mcal NEm/kg with and without an ionophore. Treatments were: i control, no ionophore; ii 30 mg/kg monensin sodium (RUM30; iii 20 mg/kg lasalocid sodium (BOV20, and iv 30 mg/kg lasalocid sodium (BOV30. Both dry matter intake (DMI and climatic variables were measured daily and the temperature humidity index (THI was estimated. The maximum THI during the study averaged 93, while the minimum was 70 (THI average = 79.2±2.3. Compared to controls, monensin supplementation did not influence average daily gain, the estimated NE value of the diet, or observed-to-expected DMI, but tended (p = 0.07 to increase (4.8% gain to feed. Compared to controls, the group fed BOV30 increased (p≤0.03 daily gain (11.8%, gain to feed (8.3%, net energy of the diet (5%, and observed-to-expected DMI (5.2%. Daily weight gain was greater (7.6%, p = 0.05 for heifers fed BOV30 than for heifers fed MON30. Otherwise, differences between the two treatments in DMI, gain to feed, and dietary NE were not statistically significant (p>0.11. Plotting weekly intakes versus THI, observed intake of controls was greater (p0.05 in the ionophores group (CV = 1.7% than in the control group (CV = 4.5%. Inclusion of ionophores in the diet resulted in relatively minor changes in carcass characteristics. It is concluded that ionophore supplementation did not exacerbate the decline of DM intake in heat-stressed cattle fed a high-energy finishing diet; on the contrary, it stabilised feed intake and favoured feed efficiency. Ionophore supplementation reduced estimated maintenance coefficients around 10% in finishing cattle during

  14. 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

  15. Cd(II and Pb(II complexes of the polyether ionophorous antibiotic salinomycin

    Directory of Open Access Journals (Sweden)

    Tanabe Makoto

    2011-09-01

    Full Text Available Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II ions in in vivo experiments, despite so far no Pb(II-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II and lead(II. Results New metal(II complexes of the polyether ionophorous antibiotic salinomycin with Cd(II and Pb(II ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa undergoes a reaction with heavy metal(II ions to form [Cd(Sal2(H2O2] (1 and [Pb(Sal(NO3] (2, respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock

  16. Improved parthenogenetic development of vitrified-warmed bovine oocytes activated with 9% ethanol plus 6-DMAP

    DEFF Research Database (Denmark)

    Hou, Y -p; Liu, Ying; Dai, Y -p

    2009-01-01

    The objective was to compare various activation protocols on developmental potential of vitrified bovine oocytes. Bovine oocytes matured in vitro for 23 h were vitrified with EDFSF30 in open pulled straws. After warming, they were cultured in vitro for 1 h, followed by parthenogenetic activation...... evaluating other activation protocols with 9% ethanol, calcium ionophore A23187, or ionomycin alone, or in combination with DMAP or cycloheximide (CHX). In conclusion, the oocyte activation protocol affected developmental capacity of vitrified bovine oocytes; 9% ethanol (5 min) followed by 6-DMAP (4 h...

  17. Effect of amiloride on arachidonic acid and histamine release from rat mast cells

    DEFF Research Database (Denmark)

    Linnebjerg, H.; Hansen, Harald S.; Jensen, B.

    1989-01-01

    The effect of a putative Na/H exchange inhibition on histamine and [C]arachidonic acid ([C]AA) release has been examined in rat peritoneal mast cells, using either addition of amiloride or removal of extracellular Na. The cells were stimulated by non-immunological agents, i.e. calcium ionophore A......23187, nerve growth factor (NGF), thapsigargin and compound 48/80. On the basis of the results obtained, a possible role for Na/H exchange in rat mast cell secretion is discussed....

  18. Functionalized zinc oxide nanorod with ionophore-membrane coating as an intracellular Ca2+ selective sensor

    Science.gov (United States)

    Asif, M. H.; Fulati, A.; Nur, O.; Willander, M.; Brännmark, Cecilia; Strâlfors, Peter; Börjesson, Sara I.; Elinder, Fredrik

    2009-07-01

    The tip of a borosilicate glass capillary with functionalized hexagonal ZnO nanorods was used to make a sensitive electrochemical intracellular Ca2+ sensor. To adjust the sensor for Ca2+ measurements with sufficient selectivity and stability, polyvinylchloride membrane containing Ca2+ ionophores were coated on the surface. The membrane covered ZnO nanorods exhibited a Ca2+-dependent electrochemical potential difference versus an Ag/AgCl reference electrode. The potential difference was linear over a large concentration range (100 nM-10 mM). The measurements of Ca2+ concentrations using our ZnO nanorods sensor in human fat cells or in frog egg cells were consistent with values of Ca2+ concentrations reported in the literature. This nanoelectrode device paves the way to measurements of intracellular biochemical species in specific locations within single living cells.

  19. Enhanced transmembrane proton conductance in Streptococcus mutans GS-5 due to ionophores and fluoride.

    Science.gov (United States)

    Eisenberg, A D; Marquis, R E

    1981-01-01

    The uptake of protons by intact cells of Streptococcus mutans GS-5 was measured directly by assessing the pH increase in lightly buffered cell suspensions as protons moved across the plasma membrane after acid pulses. The barrier function of the cell membrane for protons was disrupted completely by 5% (vol/vol) butanol. This function was compromised severely by the ionophores valinomycin and gramicidin and by the uncoupler carbonylcyanide-m-chlorophenyl hydrazone. Proton conduction across the membrane was also enhanced by fluoride. It appeared that HF traversed the membrane and acted as a carrier. Once in the relatively alkaline cytoplasm, HF dissociated to yield F- and H+, which acted to acidify the cytoplasm and reduced the pH difference across the membrane. PMID:6170255

  20. Quantitative proteomic studies in resistance mechanisms of Eimeria tenella against polyether ionophores.

    Science.gov (United States)

    Thabet, Ahmed; Honscha, Walther; Daugschies, Arwid; Bangoura, Berit

    2017-05-01

    Polyether ionophores are widely used to treat and control coccidiosis in chickens. Widespread use of anticoccidials resulted in worldwide resistance. Mechanisms of resistance development and expansion are complex and poorly understood. Relative proteomic quantification using LC-MS/MS was used to compare sensitive reference strains (Ref-1, Ref-2) with putatively resistant and moderately sensitive field strains (FS-R, FS-mS) of Eimeria tenella after isotopic labelling with tandem mass tags (TMT). Ninety-seven proteins were identified, and 25 of them were regulated. Actin was significantly upregulated in resistant strains in comparison with their sensitive counterparts. On the other hand, microneme protein (MIC4) was downregulated in resistant strains. Optimization of labelling E. tenella sporozoites by TMT might identify further proteins that play a role in the obvious complex mechanism leading to resistance against Monensin.

  1. Factors controlling acid tolerance of Listeria monocytogenes: effects of nisin and other ionophores.

    Science.gov (United States)

    Datta, A R; Benjamin, M M

    1997-01-01

    The acid tolerance of a Listeria monocytogenes serotype 4b strain was studied by measuring its ability to survive at an acidic pH at 37 degrees C. The acid tolerance of L. monocytogenes was much lower than those of Escherichia coli O157:H7 and Shigella flexneri strains. This observation suggested a higher infective dose for L. monocytogenes than E. coli O157:H7 and Shigella. The susceptibility of L. monocytogenes to acidic pH was dependent upon growth medium pH and growth phase of the culture. Nisin and some other ionophores reduced the acid tolerance of both stationary-phase and log-phase cultures of L. monocytogenes. These studies indicated that nisin might be a useful candidate for controlling acid tolerance of L. monocytogenes. PMID:9327581

  2. A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Mohammad Nooredeen; Hend Samy Amer [National Research Centre, Cairo (Egypt)

    2013-04-15

    A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from 3 Χ 10{sup -7} to 1 Χ 10{sup -2} M and a lower detection limit (LDL) of 1 Χ 10{sup -7} M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

  3. Oriented growth of Blastocladiella emersonii in gradients of ionophores and inhibitors.

    Science.gov (United States)

    Harold, R L; Harold, F M

    1980-01-01

    To investigate whether ion currents help to localize growth and development of Blastocladiella emersonii, we grew the organisms in gradients of various ionophores and inhibitors. Gradients were generated by placing into the culture fine glass fibers coated with insoluble inhibitors; in some cases, inhibitors were adsorbed onto beads of ion-exchange resin. Organisms growing in many of these gradients exhibited a striking tendency for the thalli to grow toward the fiber. This proved to be misleading; the cells grew not toward the source of the ionophore but into the unoccupied zone of inhibition adjacent to the fiber. Fibers coated with gramicidin-D induced marked effects on the growth of the rhizoids, which were greatly enlarged and grew toward and onto the fiber. None of the other inhibitors produced such effects, except for beads coated with the proton conductors tetrachlorosalicylanilide and compound 1799. The results suggest that orientation of rhizoid growth results from enhancement of proton flux across the plasma membrane. Growth of the rhizoids was also strongly oriented by gradients of inorganic phosphate and an amino acid mixture; gradients of glucose, K+, Ca2+, and glutamate were ineffective. We propose that a major physiological function of the rhizoid is to transport nutrients to the thallus. Finally, we examined the effects of a series of benzimidazole antitubulins as well as the cytochalasins. These did not orient growth but grossly perturbed the pattern of cellular organization, producing small spherical cells with multiple stunted rhizoids. The findings are interpreted in terms of the interaction of an endogenous transcellular proton current with elements of the cytoskeleton in the determination of form. Images PMID:6160142

  4. Sulfadiazine-selective determination in aquaculture environment: selective potentiometric transduction by neutral or charged ionophores.

    Science.gov (United States)

    Almeida, S A A; Heitor, A M; Montenegro, M C B S M; Sales, M G F

    2011-09-15

    Solid-contact sensors for the selective screening of sulfadiazine (SDZ) in aquaculture waters are reported. Sensor surfaces were made from PVC membranes doped with tetraphenylporphyrin-manganese(III) chloride, α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin ionophores that were dispersed in plasticizer. Some membranes also presented a positive or a negatively charged additive. Phorphyrin-based sensors relied on a charged carrier mechanism. They exhibited a near-Nernstian response with slopes of 52 mV decade(-1) and detection limits of 3.91×10(-5) mol L(-1). The addition of cationic lipophilic compounds to the membrane originated Nernstian behaviours, with slopes ranging 59.7-62.0 mV decade(-1) and wider linear ranges. Cyclodextrin-based sensors acted as neutral carriers. In general, sensors with positively charged additives showed an improved potentiometric performance when compared to those without additive. Some SDZ selective membranes displayed higher slopes and extended linear concentration ranges with an increasing amount of additive (always ionophore). The sensors were independent from the pH of test solutions within 2-7. The sensors displayed fast response, always <15s. In general, a good discriminating ability was found in real sample environment. The sensors were successfully applied to the fast screening of SDZ in real waters samples from aquaculture fish farms. The method offered the advantages of simplicity, accuracy, and automation feasibility. The sensing membrane may contribute to the development of small devices allowing in locus measurements of sulfadiazine or parent-drugs. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Novel potentiometric sensors based on polysulfone immobilized metallothioneins as metal-ionophores.

    Science.gov (United States)

    González-Bellavista, Anna; Atrian, Silvia; Muñoz, Maria; Capdevila, Mercè; Fàbregas, Esteve

    2009-02-15

    We show here the use of immobilized metal-binding biomolecules for metal analysis by using novel potentiometric sensors. To this end and as a model, Ag(+)-ISEs were developed using polysulfone matrix embedding metallothioneins as ionophores (mouse MT1 (P1) or sea urchin SpMTA (P2)). Polysulfone, a porous polymer that was not used until the present in potentiometric biosensors, has the advantage of being compatible with biological materials. Also, the phase inversion procedure allows protein incorporation into the membrane with minima alterations, since it always remains in the aqueous phase. Construction of these biosensors required small amounts of protein; they can be dry-stored and have long lifetimes. They exhibited linear responses with slopes of ca. 61mV per decade within the 10(-5) to 10(-2)M Ag(+) concentration range, detection limits of about 10(-5)M, and worked in the 2-to-8 pH range. Except for Hg(2+), the Pb(2+), Zn(2+), Cd(2+), Cu(2+) cations do not interfere with Ag(+) determination. Significantly, different affinities of Pb(2+) and Zn(2+) towards P1- and P2-ISE were found, in good correlation with the higher affinity of these cations towards SpMTA than to MT1. Consequently, the distinct metal-binding features of each MT are conserved and determine the differential properties of their biosensors. These results open a broad range of possibilities for the use of proteins as ionophores in what could be considered a new type of potentiometric biosensor if their response mechanism is taken into account.

  6. Comparative studies of ONNO-based ligands as ionophores for palladium ion-selective membrane sensors.

    Science.gov (United States)

    Gupta, Vinod K; Goyal, Rajendra N; Sharma, Ram A

    2009-04-30

    Palladium sensors based on two neutral ionophores, N,N'-bis(acetylacetone) cyclohexanediamine (L(1)) and N,N'-bis(o-hydroxyacetophenone)-1,2-cyclohexanediamine (L(2)) for quantification of palladium ions are described. Effect of various plasticizers (o-NPOE, DBP, DEP, DOP, TBP, and CN) and anion excluder, sodium tetra phenyl borate (NaTPB) has been studied. The best performance is obtained with a membrane composition of PVC:o-NPOE:ionophore (L(1)):NaTPB of 150:300:5:5 (%, w/w). The sensor exhibits significantly enhanced selectivity towards palladium ion over the concentration range 1.0 x 10(-8) to 1.0 x 10(-1)M with a lower detection limit of 4.0 x 10(-9)M and a Nernstian compliance (29.1+/-0.3 mV decade(-1) of activity) within pH range 2.0-6.0 and fast response time of 10s. Influence of the membrane composition and possible interfering ions has also been investigated on the response properties of the electrode. Fast and stable response, good reproducibility and long-term stability of the sensor are demonstrated. The sensor has been found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 4 months. Selectivity coefficients determined with fixed interference method (FIM) indicate high selectivity for palladium. The proposed electrode shows fairly good discrimination of palladium from other cations. The application of prepared sensor has been demonstrated in determination of palladium ions in spiked water sample.

  7. Release of relaxin-like gonad-stimulating substance from starfish radial nerves by lonomycin.

    Science.gov (United States)

    Mita, Masatoshi

    2013-07-01

    In starfish, the peptide hormone gonad-stimulating substance (GSS) secreted from nervous tissue stimulates oocyte maturation to induce 1-methyladenine (1-MeAde) production by ovarian follicle cells. Recently, GSS was purified from radial nerves of the starfish Asterina pectinifera and identified as a relaxin-like peptide. This study examines the mechanism of GSS secretion from radial nerves. When radial nerves isolated from A. pectinifera were incubated in artificial seawater containing ionomycin as a calcium ionophore, GSS release increased in a dose-dependent manner; 50% activity of GSS release was obtained with approximately 10 µM ionomycin. Another calcium ionophore, A23187, also stimulated GSS release from radial nerves. In contrast, membrane permeable cyclic AMP and cyclic GMP analogs failed to induce GSS release. These results suggest that GSS secretion is induced by intracellular Ca(2+) as a second messenger.

  8. A specific assay for leukotriene B4 in human whole blood

    DEFF Research Database (Denmark)

    Fogh, J; Poulsen, L K; Bisgaard, H

    1992-01-01

    . Heparinized blood was stimulated with calcium-ionophore A23187 at 37 degrees C. After 30 min cells were separated by centrifugation. LTB4 was analyzed by radioimmunoassay (RIA). When sample preparation was restricted to protein precipitation with acetone, interference was demonstrated by lack of parallelism...... between standard and sample dilution curves. Purification was, therefore, extended by combinations of the following steps: 1) protein precipitation, 2) lipid extractions, and 3) high-performance liquid chromatography (HPLC). One of two commercially available LTB4 standards was found to contain multiple...... procedure, including 1) solid-phase extraction, 2) protein precipitation at -20 degrees C, and 3) HPLC, was able to eliminate interference in RIA. Using this procedure, the recovery was 78%. Stimulation of whole blood from normal subjects with calcium-ionophore showed optimal LTB4 production at 10 micro...

  9. Effect of methylmercury on histamine release from rat mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Graevskaya, Elizabeth E.; Rubin, Andrew B. [Moscow State University, Biological Faculty, Department of Biophysics, 119899, Vorobjovy Gory, Moscow (Russian Federation); Yasutake, Akira; Aramaki, Ryoji [National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008 (Japan)

    2003-01-01

    Methylmercury chloride (MeHgCl) is well known as a significant environmental hazard, particularly as a modulator of the immune system. As it is acknowledged that the critical effector cells in the host response participating in various biological responses are mast cells, we tried to define the possible contribution of mast cells in the development of methylmercury-evoked effects. We investigated the effects of methylmercury on the rat mast cell degranulation induced by non-immunological stimuli (the selective liberator of histamine, compound 48/80, and calcium ionophore A23187) both in vivo and in vitro. Using the cells prepared from methylmercury-intoxicated rats through a 5-day treatment of MeHgCl (10 mg/kg/day), we observed the suppression of calcium ionophore A23187- and 48/80-induced histamine release, which was enhanced with time after treatment. Similar suppression was observed in the ionophore-stimulated release, when cells were prepared from rat with a single treatment of MeHgCl (20 mg/kg). It should be noted that when cells from the control rat were pre-incubated with methylmercury in vitro at a 10{sup -8} M concentration for 10 min, A23187 and compound 48/80-stimulated histamine release was significantly enhanced. However, when the pre-incubation period was prolonged to 30 min, the release was suppressed. An increase in the methylmercury concentration to 10{sup -6} M also suppressed the histamine release. These results show that methylmercury treatment can modify mast cell function depending on concentration and time, and might provide an insight into the role of mast cells in the development of methylmercury-stimulated effects. (orig.)

  10. NP-313, 2-acetylamino-3-chloro-1,4-naphthoquinone, a novel antithrombotic agent with dual inhibition of thromboxane A(2) synthesis and calcium entry.

    Science.gov (United States)

    Kuo, Heng-Lan; Lien, Jin-Cherng; Chang, Chien-Hsin; Chung, Ching-Hu; Kuo, Sheng-Chu; Hsu, Chun-Chieh; Peng, Hui-Chin; Huang, Tur-Fu

    2011-04-01

    1,4-Naphthoquinones exhibit antiplatelet activity both in vivo and in vitro. In the present study, we investigated the antiplatelet effect of a novel naphthoquinone derivative NP-313, 2-acetylamino-3-chloro-1,4-naphthoquinone and its mechanism of action. We measured platelet aggregation, Ca(2+) mobilization, thromboxane B2 formation and P-selectin expression and examined several enzymatic activities. Furthermore, we used the irradiated mesenteric venules in fluorescein sodium-treated mice to monitor the antithrombotic effect of NP-313 in vivo. NP-313 concentration-dependently inhibited human platelet aggregation induced by collagen, arachidonic acid, thapsigargin, thrombin and A23187. NP-313 also inhibited P-selectin expression, thromboxane B(2) formation and [Ca(2+) ](i) elevation in platelets stimulated by thrombin and collagen. NP-313 at 10 µM inhibited cyclooxygenase, thromboxane A(2) synthase, and protein kinase Cα, whereas it did not affect phospholipase A(2) or phospholipase C activity. In the presence of indomethacin and an adenosine 5-diphosphate scavenger, NP-313 concentration-dependently inhibited thrombin- and A23187-induced [Ca(2+)](i) increase through its inhibitory effects on Ca(2+) influx, rather than blocking Ca(2+) release from intracellular stores. NP-313 also inhibited thapsigargin-mediated Ca(2+) influx through store-operated calcium channel but had no effect on Ca(2+) influx through store-independent calcium channel evoked by the diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol. Nevertheless, it had little effect on cyclic AMP and cyclic GMP levels. Also, intravenously administered NP-313 dose-dependently inhibited the thrombus occlusion of the irradiated mesenteric vessels of fluorescein-pretreated mice. Taken together, these results indicate that NP-313 exerts its antithrombotic activity through dual inhibition of thromboxane A(2) synthesis and Ca(2+) influx through SOCC. © 2011 The Authors. British Journal of Pharmacology © 2011

  11. Intoxicação por antibióticos ionóforos em animais Ionophore poisoning in animals

    Directory of Open Access Journals (Sweden)

    Vivian Assunção Nogueira

    2009-03-01

    Full Text Available O uso terapêutico de antibióticos ionóforos em medicina veterinária difundiu-se muito nos últimos anos, com conseqüente aumento no risco de intoxicação em animais. Antibióticos ionóforos são usados como coccidiostáticos e como aditivo em alimentos para animais, com o propósito de estimular o desenvolvimento e o ganho de peso. Os ionóforos mais utilizados na alimentação de animais são a monensina, lasalocida, nasarina e salinomicina. Há uma grande variação na susceptibilidade dos efeitos tóxicos dos ionóforos de acordo com a espécie animal. A intoxicação pode ocorrer quando dosagens elevadas de ionóforos são adicionadas aos alimentos, ou quando ionóforos são incluídos inadvertidamente ou acidentalmente em dosagens não corretas para determinada espécie animal. Casos de intoxicação têm sido descritos em bovinos, ovinos, suínos, eqüinos, cães e aves. Para os eqüinos os ionóforos são extremamente tóxicos. São considerados seguros quando usados nas espécies-alvo, dentro das dosagens recomendadas pelo fabricante.The therapeutic use of ionophores in veterinary medicine has grown in the last years, with resultant increase in the risk of poisoning in animals. Ionophores are used as food additives as coccidiostacts in several animal species and growth promoter and bloat prevention in ruminants. The most often used ionophores are monensin, lasalocid, narasin and salinomycin. There is a great variation in the susceptibility to the toxic effect of ionophores in different animal species. Poisoning can occur when the dosage is too high or when not correct doses for a certain animal species are given. Cases of poisoning have been described in sheep, swine, horses, dogs and poultry. For horses ionophores are extremely toxic. The use of ionophores is only safe when used accordingly to the instructions of the manufacturer and especially for each animal species. In this paper the most important data regarding clinical

  12. Get Enough Calcium

    Science.gov (United States)

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

  13. Calcium carbonate overdose

    Science.gov (United States)

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

  14. A selective optical sensor based on [9]mercuracarborand-3, a new type of ionophore with a chloride complexing cavity

    Science.gov (United States)

    Badr, I. H.; Johnson, R. D.; Diaz, M.; Hawthorne, M. F.; Bachas, L. G.; Daunert, S. (Principal Investigator)

    2000-01-01

    A highly selective optical sensor for chloride, based on the multidentate Lewis acid ionophore [9]mercuracarborand-3, is described herein. This sensor is constructed by embedding the mercuracarborand ionophore, a suitable pH-sensitive lipophilic dye, and lipophilic cationic sites in a plasticized polymeric membrane. The multiple complementary interactions offered by the preorganized complexing cavity of [9]mercuracarborand-3 is shown to control the anion selectivity pattern of the optical film. The film exhibits a significantly enhanced selectivity for chloride over a variety of lipophilic anions such as perchlorate, nitrate, salicylate, and thiocyanate. Furthermore, the optical selectivity coefficients obtained for chloride over other biologically relevant anions are shown to meet the selectivity requirements for the determination of chloride in physiological fluids, unlike previously reported chloride optical sensors. In addition, the optical film responds to chloride reversibly over a wide dynamic range (16 microM-136 mM) with fast response and recovery times.

  15. Identification of Yeast Mutants Exhibiting Altered Sensitivity to Valinomycin and Nigericin Demonstrate Pleiotropic Effects of Ionophores on Cellular Processes.

    Science.gov (United States)

    Jakubkova, Michaela; Dzugasova, Vladimira; Truban, Dominika; Abelovska, Lenka; Bhatia-Kissova, Ingrid; Valachovic, Martin; Klobucnikova, Vlasta; Zeiselova, Lucia; Griac, Peter; Nosek, Jozef; Tomaska, Lubomir

    2016-01-01

    Ionophores such as valinomycin and nigericin are potent tools for studying the impact of ion perturbance on cellular functions. To obtain a broader picture about molecular components involved in mediating the effects of these drugs on yeast cells under respiratory growth conditions, we performed a screening of the haploid deletion mutant library covering the Saccharomyces cerevisiae nonessential genes. We identified nearly 130 genes whose absence leads either to resistance or to hypersensitivity to valinomycin and/or nigericin. The processes affected by their protein products range from mitochondrial functions through ribosome biogenesis and telomere maintenance to vacuolar biogenesis and stress response. Comparison of the results with independent screenings performed by our and other laboratories demonstrates that although mitochondria might represent the main target for both ionophores, cellular response to the drugs is very complex and involves an intricate network of proteins connecting mitochondria, vacuoles, and other membrane compartments.

  16. Complexes of tetra-tert-butyl-tetraazaporphine with Al(III) and Zr(IV) cations as fluoride selective ionophores.

    Science.gov (United States)

    Górski, Lukasz; Mroczkiewicz, Monika; Pietrzak, Mariusz; Malinowska, Elzbieta

    2009-02-09

    In this work, complexes of Zr(IV) and Al(III) cations with 2,7,12,17-tetra-tert-butyl-5,10,15,20-tetraazaporphine (TAP) were tested as ionophores in plasticized PVC membranes of ion-selective electrodes. It was found that both tested ionophores show enhanced affinity towards fluoride anion. High fluoride selectivity was observed in the presence of anionic or cationic additives in the membrane, which indicates that proposed compounds work according to charged or neutral carrier mechanism, depending on membrane composition and pretreatment. tert-Butyl substituents, present in the structure of tested compounds, were supposed to prevent formation of ionophore dimers within the membrane phase. This process was found to be responsible for some unfavorable potentiometric properties of electrodes based on complexes of Zr(IV) and Al(III) cations with porphyrins (compounds closely related to tetra-tert-butyl-5,10,15,20-tetraazaporphine). As it was shown using spectrophotometrical measurements, Al(III)-TAP was not susceptible to dimerization, while dimer formation was observed for Zr(IV)-TAP. In full agreement with these observations, electrodes with membranes containing Al(III)-TAP responded in near-Nernstian and fast manner towards fluoride anion, while the employment of Zr(IV)-TAP as ionophore resulted in super-Nernstian and sluggish response. Plasticized PVC membranes doped with Al(III)-TAP and 20mol% of lipophilic anionic additives shown remarkable F(-) selectivity, with selectivity coefficients, logK(F-pot.).(Y-), as follows: -4.4 (Y(-)Br(-)), -4.3 (Cl(-)), -4.2 (NO(3)(-)), -3.6 (SCN(-)), -2.9 (ClO(4)(-)).

  17. Fluoride-selective polymeric membrane electrodes based on Zr(IV)- and Al(III)-salen ionophores of various structures.

    Science.gov (United States)

    Górski, Łukasz; Matusevich, Alexey; Parzuchowski, Paweł; Łuciuk, Iwona; Malinowska, Elzbieta

    2010-04-14

    Al(III)- and Zr(IV)-salophens of novel structures were tested as anion-selective ionophores. It was shown that these compounds are highly selective to fluoride and give selectivity greatly deviating from classical Hofmeister pattern, when doped into the polymeric membrane of ion-selective electrode (ISE). The following selectivity sequence has been recorded for both ionophores: F(-) > ClO(4)(-) > SCN(-) > NO(3)(-) approximately Br(-) approximately Cl(-). The results of potentiometric and spectrophotometric measurements allow to conclude that the nature and structure of salophen ligands influence stability of ISE working parameters. An increase in salophen ligands lipophilicity results in prolongation of the ISE lifetime, most likely due to slower ionophore decomposition caused by the hydrolysis of imine bonds in salophen structure. Ion-selective electrodes (ISEs) with the most successful Al(III)-salophen exhibited a stable, fast and near-Nernstian fluoride response and a functional lifetime near 3 weeks and selectivity coefficients with log K(F(-), Y(-))(pot) as follows: -2.8 (Y(-)=Br(-)), -2.7 (Cl(-)), -2.8 (NO(3)(-)), -1.5 (SCN(-)), -1.3 (ClO(4)(-)), which is better than for other ones based on Zr(IV)- and Al(III)-salophens and salens described to date. Copyright 2010 Elsevier B.V. All rights reserved.

  18. 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,

  19. EFFECT OF SIMULTANEOUS APPLICATION OF GROWTH PROMOTER ANTIBIOTIC AND IONOPHOROUS ANTICOCCIDIAL ON THE PERFORMANCE OF BROILERS

    Directory of Open Access Journals (Sweden)

    Zahid, Iqbal, T. N. Pasha, A. Khalique and H. A Hashmi1

    2001-07-01

    Full Text Available The effect of growth promoter antibiotic Flavomycin 80® (FLA and an ionophorous anticoccidial Sacox® (SAC on the performance of broilers was studied. The supplements were fed as single feed additive or in combination. Two hundred and forty one-day-old broiler chicks were reared for 42 days. The birds were randomly divided into 8 groups i.e. A1, A2, B1, B2, C1, C2, D1 and D2 comprising of 30 birds each. There were four dietary treatments i.e. 0 (A1, A2, 9 mg Flavomycin 80®/kg feed (B1, B2, 60 mg Sacox@/kg feed (C1, C2 and 9 mg Flavomycin 80® + 60 mg Sacox@/kg feed (Dl, D2o Groups A2, B2, C2 and D2 were given a challenge dose of coccidial oocysts. Weight gain, feed consumption, oocysts in the faeces, clinical findings and mortality was recorded. Flavomycin 80® gave significantly (P<0.05 better performance than all other groups under controlled conditions i.e. free of coccidia whereas under challenged conditions combination of the two drugs gave better results.

  20. Cesium ionophore II as an extraordinarily effective macrocyclic receptor for the barium cation

    Science.gov (United States)

    Makrlík, Emanuel; Böhm, Stanislav; Vaňura, Petr

    2015-02-01

    On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Ba2+(aq) + 2ClO4-(aq) + 1(nb) ⇄ 1·Ba2+(nb) + 2ClO4- (nb) occurring in the two-phase water-nitrobenzene system (1 = cesium ionophore II; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (1·Ba2+, 2ClO4-) = 3.4 ± 0.1. Further, the extremely high stability constant of the 1·Ba2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Ba2+) = 16.7 ± 0.1. Finally, applying quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·Ba2+ was derived. In the resulting 1·Ba2+ complex, the "central" cation Ba2+ is bound by four very strong bonding interactions to the respective four oxygen atoms of the parent receptor 1. The interaction energy, E(int), of the considered 1·Ba2+ complex was found to be -1050.4 kJ/mol, confirming also the formation of this significant complex.

  1. Complexation of the sodium cation with sodium ionophore III: Experimental and theoretical study

    Science.gov (United States)

    Makrlík, Emanuel; Kvíčala, Jaroslav; Vaňura, Petr

    2014-06-01

    By using extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Na+(aq) + A-(aq) + 1(nb) ⇄ 1·Na+(nb) + A-(nb) occurring in the two-phase water - nitrobenzene system (A- = picrate, 1 = sodium ionophore III; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (1·Na+, A-) = 1.5 ± 0.1. Further, the stability constant of the 1·Na+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Na+) = 6.7 ± 0.1. Finally, applying quantum mechanical DFT calculations, the most probable structure of the nonhydrated 1·Na+ and hydrated 1·Na+·2H2O cationic complex species were derived. In both of these complexes, the “central” cation Na+ is bound by four bonding interactions to the corresponding four oxygen atoms of the parent ligand 1. Besides, in the case of 1·Na+·2H2O complex, the considered hydrated structure is stabilized by two water molecules bound to the “central” sodium cation.

  2. Lithium ionophore VIII as an extraordinarily effective receptor for the strontium cation: Experimental and theoretical study

    Science.gov (United States)

    Makrlík, Emanuel; Novák, Vít; Vaňura, Petr; Bouř, Petr

    2014-03-01

    From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Sr2+(aq) + 2A-(aq) + 1(nb) ⇔ 1ṡSr2+(nb) + 2A-(nb) taking place in the two-phase water-nitrobenzene system (A- = picrate, 1 = lithium ionophore VIII; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (1ṡSr2+, 2A-) = 7.8 ± 0.1. Further, the extremely high stability constant of the 1ṡSr2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1ṡSr2+) = 16.9 ± 0.1. Finally, by using DFT calculations, the most probable structure of the cationic complex species 1ṡSr2+ was derived. In the resulting complex, the "central" cation Sr2+ is bound by six very strong bond interactions to the corresponding six oxygen atoms of the parent ligand 1; the interaction energy of this complex was found to be -959.9 kJ/mol.

  3. Lithium ionophore VIII as an extraordinarily strong receptor for the trivalent europium cation

    Science.gov (United States)

    Makrlík, Emanuel; Novák, Vít; Vaňura, Petr

    2015-01-01

    On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Eu3+(aq) + 3A-(aq) + 1(nb) ⇆ 1.Eu3+(nb) + 3A-(nb) occurring in the two-phase water-nitrobenzene system (A- = CF3SO-3; 1 = lithium ionophore VIII; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (1.Eu3+, 3A-) = 2.5 ± 0.1. Furthermore, the extremely high stability constant of the 1.Eu3+ complex in nitrobenzene saturated with water was calculated: log βnb (1.Eu3+) = 15.6 ± 0.1. Finally, by using DFT calculations, the most probable structure of the cationic complex species 1.Eu3+ was derived. In the resulting complex, the 'central' cation Eu3+ is bound by six very strong bond interactions to the corresponding six oxygen atoms of the parent ligand 1. It is evident that this exceptionally effective receptor 1 for the Eu3+ cation could be considered as a potential extraction agent for nuclear waste treatment.

  4. Ionophore-based potentiometric PVC membrane sensors for determination of phenobarbitone in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Alrabiah Haitham

    2016-12-01

    Full Text Available The fabrication and development of two polyvinyl chloride (PVC membrane sensors for assaying phenobarbitone sodium are described. Sensors 1 and 2 were fabricated utilizing β- or γ-cyclodextrin as ionophore in the presence of tridodecylmethylammonium chloride as a membrane additive, and PVC and dioctyl phthalate as plasticizer. The analytical parameters of both sensors were evaluated according to the IUPAC guidelines. The proposed sensors showed rapid, stable anionic response (-59.1 and -62.0 mV per decade over a relatively wide phenobarbitone concentration range (5.0 × 10-6-1 × 10-2 and 8 × 10-6-1 × 10-2 mol L-1 in the pH range of 9-11. The limit of detection was 3.5 × 10-6 and 7.0 × 10-6 mol L-1 for sensors 1 and 2, respectively. The fabricated sensors showed high selectivity for phenobarbitone over the investigated foreign species. An average recovery of 2.54 μg mL-1 phenobarbitone sodium was 97.4 and 101.1 %, while the mean relative standard deviation was 3.0 and 2.1 %, for sensors 1 and 2, respectively. The results acquired for determination of phenobarbitone in its dosage forms utilizing the proposed sensors are in good agreement with those obtained by the British Pharmacopoeial method.

  5. Thiopental and Phenytoin as Novel Ionophores for Potentiometric Determination of Lead (II Ions

    Directory of Open Access Journals (Sweden)

    Yasser M. Abd EL-Karem

    2009-03-01

    Full Text Available Two novel polymeric membrane sensors for the analysis of Pb(II have been developed based ontwo therapeutic drugs, thiopental (TP and phenytoin (PT as two new ionophores and potassium tetrakis(p-chlorophenyl borate (KTpClPB as a lipophilic additive, in plasticized PVC membranes. The sensors show a Nernstian response for Pb(II ions over the wide concentration ranges of 1×10-2 - 7×10-6 M and 1×10-2 - 8×10-6 M for the sensors based on thiopental and phenytoin, respectively. The proposed sensors have a fast response time and can be used for more than nine weeks without any considerable divergence in potentials. The sensors exhibit comparatively good selectivity with respect to alkaline, alkaline earth and some transition and heavy metal ions. They were employed for direct determination of lead in solder alloys and in galena rocks with a good agreement with the obtained results by atomic absorption spectroscopy.

  6. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)]. E-mail: vinodfcy@iitr.ernet.in; Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India); Gupta, Barkha [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

    2007-02-05

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S{sub 1}) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S{sub 1}) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10{sup -8} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 5.0 x 10{sup -8} M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

  7. Differentiated Paju cells have increased resistance to toxic effects of potassium ionophores.

    Science.gov (United States)

    Teplova, Vera; Jääskeläinen, Elina; Salkinoja-Salonen, Mirja; Saris, Nils-Erik L; Serlachius, Martina; Li, Feng-Yen; Andersson, Leif C

    2004-01-01

    In this study we have investigated the impact of differentiation of neuronal cells on their sensitivity to microbial toxins. We used the human neural crest-derived tumor cell line Paju, which can be induced to differentiation in vitro by treatment with phorbol 12-myristate 13-acetate. Addition of the highly toxic potassium ionophores cereulide (4.5 and 9.0 ng/ml) or valinomycin (20 ng/ml), to cultures of undifferentiated Paju cells caused collapse of the mitochondrial membrane potential - measured with the fluorescent probe 5,5',6,6'-tetrachloro-1,1',3,3'-tetrabenzimidazole carbocyanine iodide (JC-1) followed by detachment of the cells and their apoptotic death. After induced differentiation of the Paju cells, their mitochondria retained the membrane potential upon exposure to the toxins and the cells displayed increased resistance to apoptosis as compared with undifferentiated cells. This effect may be caused by an elevated expression of the anti-apoptotic protein Bcl-2 and of the neuroprotective factor, stanniocalcin, in differentiated cells.

  8. Effect of ionophores on the rate of intramolecular cation exchange in durosemiquinone ion pairs

    Science.gov (United States)

    Eastman, M. P.; Bruno, G. V.; Mcguyer, C. A.; Gutierrez, A. R.; Shannon, J. M.

    1979-01-01

    The effects of the ionophores 15-crown-5 (15C5), 18-crown-6 (18C6), dibenzo-18-crown-6 (DBC) and cryptand 222 (C222) on intramolecular cation exchange in ion pairs of the sodium salt of the durosemiquinone anion in benzene solution are investigated. Electron paramagnetic resonance spectra of the 18C6 and 15C5 complexes with durosemiquinone reduced by contact with a sodium mirror show an alternating line width which indicates that the sodium ion is being exchanged between equivalent sites near the oxygens of the semiquinone with activation energies of 8.7 and 6.0 kcal/mole and Arrhenius preexponential factors of 9 x 10 to the 12th/sec and 10 to the 12th/sec, respectively. Spectra obtained for the DBC complexes show no evidence of exchange, while those of C222 indicate rapid exchange. It is also noted that the hyperfine splitting constants measured do not change over the 50-K temperature interval studied.

  9. New ionophores for vitamin B1 and vitamin B6 potentiometric sensors for multivitaminic control.

    Science.gov (United States)

    Pires, Ana Rita; Araújo, Alberto N; Montenegro, M Conceição B S M; Chocholous, Petr; Solich, Petr

    2008-03-13

    The construction, evaluation and analytical application of potentiometric sensors sensitive to vitamin B1 and vitamin B6 are reported. The solid contact electrodes were produced using beta-cyclodextrins as ionophores in a carboxylated poly(vinyl chloride) support matrix. Near Nernstian slopes (mV/decade) of 51.7+/-0.8, 60.6+/-0.6 and 61.1+/-1.4, within the intervals (M) of 1.0 x 10(-4) to 1.0 x 10(-1), 5.8 x 10(-5) to 1.0 x 10(-1) and 4.3 x 10(-5) to 1.0 x 10(-1) were obtained, for thiamine and pyridoxine I and II prepared membranes, respectively. A pH operational range of 6.5-8.5 for thiamine and 2-4.5 for pyridoxine electrodes was found. Assessment of selectivity coefficients toward a large number of inorganic cations and organic cations usually present in multivitamin formulations revealed good performance. Analysis of vitamins B1 and B6 in complex multivitamin drugs was achieved with recoveries within the intervals of 95.1-99.6% for thiamine and 95.1-102% for pyridoxine. Furthermore, the results enabled by the proposed procedure revealed good agreement with those provided by HPLC.

  10. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes.

    Science.gov (United States)

    Gupta, V K; Singh, A K; Gupta, Barkha

    2007-02-05

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S1) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S2) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S1) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9x10(-8) to 1.0x10(-1) M Cd2+ with limit of detection 5.0x10(-8) M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

  11. Degradation and dissipation of the veterinary ionophore lasalocid in manure and soil.

    Science.gov (United States)

    Žižek, Suzana; Dobeic, Martin; Pintarič, Štefan; Zidar, Primož; Kobal, Silvestra; Vidrih, Matej

    2015-11-01

    Lasalocid is a veterinary ionophore antibiotic used for prevention and treatment of coccidiosis in poultry. It is excreted from the treated animals mostly in its active form and enters the environment with the use of contaminated manure on agricultural land. To properly assess the risk that lasalocid poses to the environment, it is necessary to know its environmental concentrations as well as the rates of its degradation in manure and dissipation in soil. These values are still largely unknown. A research was undertaken to ascertain the rate of lasalocid degradation in manure under different storage conditions (aging in a pile or composting) and on agricultural soil after using lasalocid-contaminated manure. The results have shown that there is considerable difference in lasalocid degradation between aging manure with no treatment (t1/2=61.8±1.7 d) and composting (t1/2=17.5±0.8 d). Half-lives in soil are much shorter (on average 3.1±0.4 d). On the basis of the measured concentrations of lasalocid in soil after manure application, we can conclude that it can potentially be harmful to soil organisms (PEC/PNEC ratio of 1.18), but only in a worst-case scenario of using the maximum permissible amount of manure and immediately after application. To make certain that no harmful effects occur, composting is recommended. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Alkaline pH Promotes NADPH Oxidase-Independent Neutrophil Extracellular Trap Formation: A Matter of Mitochondrial Reactive Oxygen Species Generation and Citrullination and Cleavage of Histone

    Directory of Open Access Journals (Sweden)

    Cristiane Naffah de Souza

    2018-01-01

    Full Text Available pH is highly variable in different tissues and affects many enzymatic reactions in neutrophils. In response to calcium ionophores such as A23187 and ionomycin, neutrophils undergo nicotinamide adenine dinucleotide phosphate oxidase (NOX-independent neutrophil extracellular trap (NET formation (NETosis. However, how pH influences calcium-dependent Nox-independent NET formation is not well understood. We hypothesized that increasing pH promotes Nox-independent NET formation by promoting calcium influx, mitochondrial reactive oxygen species (mROS generation, histone citrullination, and histone cleavage. Here, we show that stimulating human neutrophils isolated from peripheral blood with calcium ionophore A23187 or ionomycin in the media with increasing extracellular pH (6.6, 6.8, 7.0, 7.2, 7.4, 7.8 drastically increases intracellular pH within in 10–20 min. These intracellular pH values are much higher compared to unstimulated cells placed in the media with corresponding pH values. Raising pH slightly drastically increases intracellular calcium concentration in resting and stimulated neutrophils, respectively. Like calcium, mROS generation also increases with increasing pH. An mROS scavenger, MitoTempo, significantly suppresses calcium ionophore-mediated NET formation with a greater effect at higher pH, indicating that mROS production is at least partly responsible for pH-dependent suppression of Nox-independent NETosis. In addition, raising pH increases PAD4 activity as determined by the citrullination of histone (CitH3 and histone cleavage determined by Western blots. The pH-dependent histone cleavage is reproducibly very high during ionomycin-induced NETosis compared to A23187-induced NETosis. Little or no histone cleavage was noted in unstimulated cells, at any pH. Both CitH3 and cleavage of histones facilitate DNA decondensation. Therefore, alkaline pH promotes intracellular calcium influx, mROS generation, PAD4-mediated CitH3 formation

  13. Coronary Calcium Scan

    Science.gov (United States)

    ... Back To Health Topics / Coronary Calcium Scan Coronary Calcium Scan Also known as Calcium Scan Test A coronary calcium scan is a CT scan of your heart that detects and measures the amount of calcium in the walls of your coronary arteries. Overview ...

  14. Detection and quantification of ionophore antibiotics in runoff, soil and poultry litter.

    Science.gov (United States)

    Sun, Peizhe; Barmaz, Delphine; Cabrera, Miguel L; Pavlostathis, Spyros G; Huang, Ching-Hua

    2013-10-18

    Ionophore antibiotics (IPAs) are widely used as coccidiostats in poultry and other livestock industries to promote growth and prevent infections. Because most of the ingested IPAs are excreted in poultry litter, which is primarily applied as grassland fertilizer, a significant amount of IPAs can be released into the litter-soil-water environment. A robust analytical method has been developed to quantify IPAs (monensin (MON), salinomycin (SAL) and narasin (NAR)) in complex environmental compartments including surface runoff, soil and poultry litter, with success to minimize matrix interference. The method for water samples involves solid-phase extraction (SPE) followed by liquid-liquid extraction (LLE) post-clean up steps. The method for solid samples involves bi-solvent LLE. IPAs were detected by HPLC-MS, with optimized parameters to achieve the highest sensitivity. Nigericin (NIG), an IPA not used in livestock industry, is successfully applied and validated as a surrogate standard. The method recoveries were at 92-95% and 81-85% in runoff samples from unfertilized and litter-fertilized fields, respectively. For solids, the method recoveries were at 93-99% in soils, and 79-83% in poultry litter samples. SAL was detected at up to 22mg/kg and MON and NAR at up to 4mg/kg in broiler litter from different farms. Up to 183μg/kg of MON was detected in litter-fertilized soils. All three IPAs were detected in the rainfall runoff from litter-fertilized lands at concentrations up to 9μg/L. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. The effect of composting on the persistence of four ionophores in dairy manure and poultry litter.

    Science.gov (United States)

    Arikan, Osman A; Mulbry, Walter; Rice, Clifford

    2016-08-01

    Manure composting is a well-described approach for stabilization of nutrients and reduction of pathogens and odors. Although composting studies have shown that thermophilic temperatures and aerobic conditions can increase removal rates of selected antibiotics, comparable information is lacking for many other compounds in untreated or composted manure. The objective of this study was to determine the relative effectiveness of composting conditions to reduce concentrations of four widely used ionophore feed supplements in dairy manure and poultry litter. Replicate aliquots of fresh poultry litter and dairy manure were amended with monensin, lasalocid, salinomycin, or amprolium to 10mgkg(-1)DW. Non-amended and amended dairy manure and poultry litter aliquots were incubated at 22, 45, 55, or 65°C under moist, aerobic conditions. Residue concentrations were determined from aliquots removed after 1, 2, 4, 6, 8, and 12weeks. Results suggest that the effectiveness of composting for contaminant reduction is compound and matrix specific. Composting temperatures were not any more effective than ambient temperature in increasing the rate or extent of monensin removal in either poultry litter or dairy manure. Composting was effective for lasalocid removal in poultry litter, but is likely to be too slow to be useful in practice (8-12weeks at 65°C for >90% residue removal). Composting was effective for amprolium removal from poultry litter and salinomycin in dairy manure but both required 4-6weeks for >90% removal. However, composting did not increase the removal rates or salinomycin in poultry litter or the removal rates of lasalocid or amprolium in dairy manure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Lead ion-selective electrodes based on polyphenylenediamine as unique solid ionophores.

    Science.gov (United States)

    Huang, Mei-Rong; Rao, Xue-Wu; Li, Xin-Gui; Ding, Yong-Bo

    2011-09-15

    A novel membrane electrode for Pb(II) ion detection based on semi-conducting poly(m-phenylenediamine) microparticles as a unique solid ionophore was fabricated. The electrode exhibited significantly enhanced response towards Pb(II) over the concentration range from 3.16×10(-6) to 0.0316 M at pH 3.0-5.0 with a low detection limit of 6.31×10(-7) M, a high sensitivity displaying a near-Nernstian slope of 29.8 mV decade(-1) for Pb(II). The electrode showed a long lifetime of 5 months and a short response time of 14s. A systematical investigation on the effect of anion excluder and various foreign ions on the selectivity of the electrode by a fixed interference method suggests that all other metal ions hardly ever interfere with the determination of Pb(II) except high concentration Hg(II). The electrode was successfully used as an indicator electrode in the potentiometric titration of Pb(II) with EDTA. Furthermore, the electrode has been used to satisfactorily analyze four types of real-world samples like spiked human urine, spiked tap water, and river water containing interfering ions like Na(I), Ca(II), Mg(II), Zn(II), Pd(II), Fe(III), K(I), Cu(II) and Hg(II) up to 8.04×10(-4) M, demonstrating fast response, high selectivity, good recovery (96.6-121.4%), good repeatability (RSD 0.31-6.45%), and small relative error (5.0%). Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Simultaneous determination of five polyether ionophores using liquid chromatography with one-step fluorescent derivatization.

    Science.gov (United States)

    Inoue, Koichi; Miura, Yukiko; Suzuki, Misato; Kishikawa, Naoya; Hino, Tomoaki; Kuroda, Naotaka; Oka, Hisao

    2012-01-01

    We present a selective method for simultaneous determination of five polyether ionophores such as salinomycin (SAL), monensin (MON), narasin (NAR), semduramicin (SEM) and lasalocid (LAS) in aquatic samples using a liquid chromatography with one-step fluorescent derivatization of 2-(4-hydrazinocarbonyl-phenyl) 4,5-diphenylimidazole (HCPI) and 4-(4,5-diphenyl-1H-imidazol-2-yl) benzoyl chloride hydrochloride (DIB-Cl). Fluorescent one-step derivatization for SAL, MON, NAR and SEM using HCPI and for LAS using DIB-Cl was monitored by an LC/fluorescence detector (E(x), 340 nm; E(m), 465 nm). Chromatographic separation was performed on a TSK-GEL ODS-120T (4.6 × 150 mm, 3 µm) column using a mobile phase of 0.1% formic acid in acetonitrile and 0.5 mM ammonium formate in water (70/30, v/v). The limits of detections were 0.01 µg/mL (50 pg) for LAS, 0.05 µg/mL (250 pg) for SAL, NAR and SEM, and 0.1 µg/mL (500 pg) for MON, respectively. The recoveries for water samples were indicated to be the range of 79.6 ± 6.4 - 99.0 ± 4.4% with associated precision values (between-day for 3 days) for repeatability. Based on solid-phase extraction, the limit of quantitation values indicated 0.1 ng/mL for SAL, MON, NAR and SEM, and 0.01 ng/mL for LAS in water samples. 2012 © The Japan Society for Analytical Chemistry

  18. Chromium(III) selective membrane sensors based on Schiff bases as chelating ionophores.

    Science.gov (United States)

    Singh, A K; Gupta, V K; Gupta, Barkha

    2007-02-28

    The two chromium chelates of Schiff bases, N-(acetoacetanilide)-1,2-diaminoethane (L(1)) and N,N'-bis(acetoacetanilide)-triethylenetetraammine (L(2)), have been synthesized and explored as neutral ionophores for preparing poly(vinylchloride) (PVC) based membrane sensors selective to Cr(III). The addition of lipophilic anion excluder (NaTPB) and various plasticizers viz. o-Nitrophenyloctyl ether (o-NPOE), dioctylpthalate (DOP), dibutylphthalate (DBP), tris(2-ethylhexyl)phosphate (TEHP), and benzyl acetate (BA) have found to improve the performance of the sensors. The best performance was obtained for the membrane sensor having a composition of L(1):PVC:DBP:NaTPB in the ratio 5:150:250:3 (w/w). The sensor exhibits Nernstian response in the concentration range 8.9 x 10(-8) to 1.0 x 10(-1) M Cr(3+) with limit of detection 5.6 x 10(-8) M. The proposed sensor manifest advantages of relatively fast response (10s) and good selectivity over some alkali, alkaline earth, transition and heavy metal ions. The selectivity behavior of the proposed electrode revealed a considerable improvement as compared to the best previously PVC-membrane electrode for chromium(III) ion. The potentiometric response of the proposed sensor was independent of pH of the test solution in the range of 2.0-7.0. The sensor has found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 3 months. The proposed electrode was used as an indicator electrode in potentiometric titration of chromium ion with EDTA and in direct determination in different water and food samples.

  19. Calcium source (image)

    Science.gov (United States)

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

  20. Calcium and bones (image)

    Science.gov (United States)

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

  1. Calcium hydroxide poisoning

    Science.gov (United States)

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

  2. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

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

  3. Calcium blood test

    Science.gov (United States)

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

  4. A forward genetic screen reveals that calcium-dependent protein kinase 3 regulates egress in Toxoplasma.

    Directory of Open Access Journals (Sweden)

    Erin Garrison

    Full Text Available Egress from the host cell is a crucial and highly regulated step in the biology of the obligate intracellular parasite, Toxoplasma gondii. Active egress depends on calcium fluxes and appears to be a crucial step in escaping the attack from the immune system and, potentially, in enabling the parasites to shuttle into appropriate cells for entry into the brain of the host. Previous genetic screens have yielded mutants defective in both ionophore-induced egress and ionophore-induced death. Using whole genome sequencing of one mutant and subsequent analysis of all mutants from these screens, we find that, remarkably, four independent mutants harbor a mis-sense mutation in the same gene, TgCDPK3, encoding a calcium-dependent protein kinase. All four mutations are predicted to alter key regions of TgCDPK3 and this is confirmed by biochemical studies of recombinant forms of each. By complementation we confirm a crucial role for TgCDPK3 in the rapid induction of parasite egress and we establish that TgCDPK3 is critical for formation of latent stages in the brains of mice. Genetic knockout of TgCDPK3 confirms a crucial role for this kinase in parasite egress and a non-essential role for it in the lytic cycle.

  5. Novel amide polar-embedded reversed-phase column for the fast liquid chromatography-tandem mass spectrometry method to determine polyether ionophores in environmental waters.

    Science.gov (United States)

    Herrero, P; Borrull, F; Pocurull, E; Marcé, R M

    2012-11-09

    A fast chromatographic method has been developed that takes less than 5 min per run to determine five polyether ionophores with a novel amide polar-embedded reversed-phase column coupled to a triple quadrupole mass spectrometer. A comparison between Oasis HLB and Oasis MAX sorbents for the solid-phase extraction was done. Oasis HLB sorbent gave recoveries close to 90% and the repeatability (%RSD, 25-100 ng/L, n=3) of the method was less than 7% for all compounds in all matrices. The presence of polyether ionophores in environmental waters such as river water and sewage was investigated. Monensin and narasin were frequently determined in influent and effluent sewage at concentrations from 10 ng/L to 47 ng/L in influents and from 6 ng/L to 34 ng/L in effluents. In river waters, polyether ionophores were not detected in any sample. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Optogenetic monitoring identifies phosphatidylthreonine-regulated calcium homeostasis in Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Arunakar Kuchipudi

    2016-05-01

    Full Text Available Toxoplasma gondii is an obligate intracellular parasite, which inflicts acute as well as chronic infections in a wide range of warm-blooded vertebrates. Our recent work has demonstrated the natural occurrence and autonomous synthesis of an exclusive lipid phosphatidylthreonine in T. gondii. Targeted gene disruption of phosphatidylthreonine synthase impairs the parasite virulence due to unforeseen attenuation of the consecutive events of motility, egress and invasion. However, the underlying basis of such an intriguing phenotype in the parasite mutant remains unknown. Using an optogenetic sensor (gene-encoded calcium indicator, GCaMP6s, we show that loss of phosphatidylthreonine depletes calcium stores in intracellular tachyzoites, which leads to dysregulation of calcium release into the cytosol during the egress phase of the mutant. Consistently, the parasite motility and egress phenotypes in the mutant can be entirely restored by ionophore-induced mobilization of calcium. Collectively, our results suggest a novel regulatory function of phosphatidylthreonine in calcium signaling of a prevalent parasitic protist. Moreover, our application of an optogenetic sensor to monitor subcellular calcium in a model intracellular pathogen exemplifies its wider utility to other entwined systems.

  7. Effects of osmolality and calcium on renin release from superfused rat glomeruli treated with nigericin or monensin

    DEFF Research Database (Denmark)

    Skøtt, O

    1988-01-01

    Proton gradients may be important for the induction of swelling and exocytosis of secretory renin granules during basal renin release (RR). The sensitivity of renin release to changes in osmolality and to calcium was therefore tested on superfused rat glomeruli that had been pretreated with the m......Proton gradients may be important for the induction of swelling and exocytosis of secretory renin granules during basal renin release (RR). The sensitivity of renin release to changes in osmolality and to calcium was therefore tested on superfused rat glomeruli that had been pretreated...... of proton gradients with the ionophores inhibit RR late in the secretory pathways, independently of effects on the Golgi-apparatus and intracellular calcium concentration. The results are consistent with the hypothesis that a low granular pH is important for driving JGC-granule swelling and exocytosis....

  8. Development and validation of an SPE methodology combined with LC-MS/MS for the determination of four ionophores in aqueous environmental matrices

    DEFF Research Database (Denmark)

    Bak, Søren Alex; Hansen, Martin; Krogh, Kristine Andersen

    2013-01-01

    A multi-residue analytical methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in aqueous environmental matrices, using nigericin as internal standard. The samples were filtrated prior to solid phase extraction. All compounds...... were measured using liquid chromatography coupled to tandem mass spectrometry applying electro spray ionisation. The absolute recoveries ranged from 92 to 110% (relative standard deviation: 2–14%) for spiked river water. The final method allowed fordetection of ionophores down to a few ng/L in natural...

  9. [Effect of damage integrity rat brain synaptic membranes on the functional activity GABA(A)-receptor/Cl(-)-ionophore complex in the CNC].

    Science.gov (United States)

    Rebrov, I G; Kalinina, M V

    2013-01-01

    Functional activity of the CGABA(A)-receptor/Cl(-) ionophore complex was investigated the muscimol-stimulated entry of the radioactive isotope 36Cl(-) in synaptoneurosomes in changing the structure and permeability of neuronal membranes. Integrity of the membranes was damaged by removal of Ca(+2) and Mg(+2) from the incubation medium and by the method of freezing-thawing synaptoneurosomes. In both cases, an increase in basal 36Cl(-) entry into synaptoneurosomes, indicating increased nonspecific permeability of neuronal membranes, and decreased activity the CABA(A)-receptor/Cl(-) ionophore complex. The conclusion about the relationship of processes damage neuronal membranes and reducing the inhibitory processes in the epileptic focus.

  10. Characterization of a new ionophore-based ion-selective electrode for the potentiometric determination of creatinine in urine.

    Science.gov (United States)

    Guinovart, Tomàs; Hernández-Alonso, Daniel; Adriaenssens, Louis; Blondeau, Pascal; Rius, F Xavier; Ballester, Pablo; Andrade, Francisco J

    2017-01-15

    The optimization, analytical characterization and validation of a novel ion-selective electrode for the highly sensitive and selective determination of creatinine in urine is presented. A newly synthesized calix[4]pyrrole-based molecule is used as an ionophore for the enhanced recognition of creatininium cations. The calculation of the complex formation constants in the polymeric membrane with creatininium, potassium and sodium confirms the strong selective interactions between the ionophore and the target. The optimization of the potentiometric sensor presented here yields an outstanding analytical performance, with a linear range that spans from 1µM to 10mM and limit of detection of 10-6.2M. The calculation of the selectivity coefficients against most commonly found interferences also show significant improvements when compared to other sensors already reported. The performance of this novel sensor is tested by measuring creatinine in real urine samples (N=50) and comparing the values against the standard colorimetric approach (Jaffé's reaction). The results show that this sensor allows the fast and accurate determination of creatinine in real samples with minimal sample manipulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. The Determination of Six Ionophore Coccidiostats in Feed by Liquid Chromatography with Postcolumn Derivatisation and Spectrofotometric/Fluorescence Detection

    Directory of Open Access Journals (Sweden)

    Małgorzata Olejnik

    2013-01-01

    Full Text Available The control of levels of anticoccidial feed additives in targeted feeds plays an important role in the assurance of efficiency of animal treatment, prevention of drug resistance, and food safety. The robust and labour-efficient method for the simultaneous determination of six ionophore coccidiostats (lasalocid, maduramicin, monensin, narasin, salinomycin, and semduramicin in targeted feed has been developed. Properly grinded and homogenized feed sample was spiked with internal standard (monesin methyl ester and extracted with methanol. The extract was analysed with reversed phase HPLC without any further purification. The separation of the analytes with conventional C18 and core-shell columns was compared. Lasalocid was analysed with fluorescence detection, whereas other ionophores were detected with UV-Vis detector after derivatisation with vanillin in the presence of sulfuric acid. Fortified samples and targeted feeds at authorized levels were used for method validation. Recovery was in the range of 85–110%, depending on the analyte. The within-laboratory reproducibility did not exceed the target value from Horwitz equation. The results of the proficiency tests (z-scores in the range of −1.0 to 1.9 confirmed the reliability of the developed protocol.

  12. Free fatty acids act as endogenous ionophores, resulting in Na+ and Ca2+ influx and myocyte apoptosis.

    Science.gov (United States)

    Fang, Kwang-Ming; Lee, An-Sheng; Su, Ming-Jai; Lin, Chien-Liang; Chien, Chung-Liang; Wu, Mei-Lin

    2008-06-01

    Disturbances in lipid metabolism have been suggested to play an important role in myocardial damage. Marked accumulation of free fatty acids (FFAs), including arachidonic acid (AA), palmitic acid, oleic acid, and linoleic acid, occurs during post-ischaemia and reperfusion (post-I/R). Possible cellular mechanisms of AA/FFAs-induced myocyte apoptosis were investigated. In neonatal rat ventricular myocytes, AA/FFAs activate a novel non-selective cation conductance (NSCC), resulting in both intracellular Ca(2+) and Na(+) overload. AA caused sustained cytosolic [Na(+)](cyt) and [Ca(2+)](cyt) overload, resulting in mitochondrial [Na(+)](m) and [Ca(2+)](m) overload, which induced caspase-3-mediated apoptosis. Similar apoptotic effects were seen using Na(+) ionophore cocktail/Ca(2+)-free medium, which induced [Na(+)](cyt) and [Na(+)](m), but not [Ca(2+)](cyt) and [Ca(2+)](m) overload. Electron microscopy showed that inhibition of [Na(+)](m) overload prevented disruption of the mitochondrial membrane, showing that [Na(+)](m) overload is an important upstream signal in AA- and FFA-induced myocyte apoptosis. AA and FFAs, which accumulate in the myocardium during post-I/R, may therefore act as naturally occurring endogenous ionophores and contribute to the myocyte death seen during post-I/R.

  13. Mdm31 protein mediates sensitivity to potassium ionophores but does not regulate mitochondrial morphology or phospholipid trafficking in Schizosaccharomyces pombe.

    Science.gov (United States)

    Ivan, Branislav; Lajdova, Dana; Abelovska, Lenka; Balazova, Maria; Nosek, Jozef; Tomaska, Lubomir

    2015-03-01

    Mdm31p is an inner mitochondrial membrane (IMM) protein with unknown function in Saccharomyces cerevisiae. Mutants lacking Mdm31p contain only a few giant spherical mitochondria with disorganized internal structure, altered phospholipid composition and disturbed ion homeostasis, accompanied by increased resistance to the electroneutral K+ /H+ ionophore nigericin. These phenotypes are interpreted as resulting from diverse roles of Mdm31p, presumably in linking mitochondrial DNA (mtDNA) to the machinery involved in segregation of mitochondria, in mediating cation transport across IMM and in phospholipid shuttling between mitochondrial membranes. To investigate which of the roles of Mdm31p are conserved in ascomycetous yeasts, we analysed the Mdm31p orthologue in Schizosaccharomyces pombe. Our results demonstrate that, similarly to its S. cerevisiae counterpart, SpMdm31 is a mitochondrial protein and its absence results in increased resistance to nigericin. However, in contrast to S. cerevisiae, Sz. pombe cells lacking SpMdm31 are also less sensitive to the electrogenic K+ ionophore valinomycin. Moreover, mitochondria of the fission yeast mdm31Δ mutant display no changes in morphology or phospholipid composition. Therefore, in terms of function, the two orthologous proteins appear to have considerably diverged between these two evolutionarily distant yeast species, possibly sharing only their participation in ion homeostasis. Copyright © 2015 John Wiley & Sons, Ltd.

  14. Effects of polyether ionophores on the protective immune responses of broiler chickens against Angara disease and Newcastle disease viruses.

    Science.gov (United States)

    Munir, K; Muneer, M A; Tiwari, A; Chaudhry, R M; Muruganandan, S

    2007-10-01

    Immunization against Angara disease virus (ADV), a serotype 4 avian adenovirus, and Newcastle disease virus (NDV), an avian paramyxovirus serotype 1, is the mainstay of a broiler vaccination programme, while polyether ionophores usually form an essential component of a broiler medication programme in most parts of India and Pakistan. The role of polyether ionophores in the protective immune responses of broiler chickens vaccinated and challenged with ADV and NDV was investigated. A total of 1600 birds were divided into eight groups of 200 birds each. First four groups were vaccinated against NDV and ADV, while the remaining four served as unvaccinated controls. The first 3 groups of birds were administered salinomycin, monensin and cyclophosphamide (CYP), respectively. The last group served as an untreated control. The same treatment schedule was also followed for the next four unvaccinated groups. The post-vaccination and post-challenge serological responses to NDV and ADV, body and lymphoid organ weight gains, post-challenge survival rate and detection of NDV and ADV in the tissues of infected birds were evaluated. Birds administered salinomycin showed a significant stimulation of protective immune responses against both NDV and ADV as compared to the untreated and CYP-treated birds. Monensin also enhanced the protective immune responses against both viruses but the effect was not statistically significant. Thus, it is concluded that monensin and salinomycin augment the anti-NDV and anti-ADV immune responses in broiler chickens, which supports their use in poultry flocks.

  15. Ionophore-based optical nanosensors incorporating hydrophobic carbon dots and a pH-sensitive quencher dye for sodium detection.

    Science.gov (United States)

    Galyean, A A; Behr, M R; Cash, K J

    2018-01-21

    Nanosensors present a biological monitoring method that is biocompatible, reversible, and nano-scale, and they offer many advantages over traditional organic indicators. Typical ionophore-based nanosensors incorporate nile-blue derivative pH indicators but suffer from photobleaching while quantum dot alternatives pose a potential toxicity risk. In order to address this challenge, sodium selective nanosensors containing carbon dots and a pH-sensitive quencher molecule were developed based on an ion-exchange theory and a decoupled recognition element from the pH indicator. Carbon dots were synthesized and integrated into nanosensors containing a pH-indicator, an analyte-binding ligand (ionophore), and a charge-balancing additive. These nanosensors are ion-selective against potassium (selectivity coefficient of 0.4) and lithium (selectivity coefficient of 0.9). Reversible nanosensor response to sodium is also demonstrated. The carbon dot nanosensors are resistant to changes in optical properties for at least 12 h and display stable selectivity to physiologically-relevant sodium (alpha = 0.5 of 200 mM NaCl) for a minimum of 6 days.

  16. Effects of ionophores and antibiotics on in vitro hydrogen sulfide production, dry matter disappearance, and total gas production in cultures with a steam-flaked corn-based substrate with or without added sulfur.

    Science.gov (United States)

    Quinn, M J; May, M L; Hales, K E; DiLorenzo, N; Leibovich, J; Smith, D R; Galyean, M L

    2009-05-01

    Effects of 3 ionophores and 2 antibiotics on in vitro H(2)S production, IVDMD, total gas production, and VFA profile with or without added S were examined. In Exp. 1, ruminal fluid from 2 ruminally cannulated steers fed a steam-flaked corn-based diet (75% concentrate) without ionophore and antibiotics for 28 d before collection was used to inoculate in vitro cultures. Treatments were control (no ionophore or antibiotic), 3 ionophores (lasalocid sodium and monensin sodium at 5 mg/L or laidlomycin propionate at 1.65 mg/L), and 2 antibiotics (chlortetracycline hydrochloride at 5 mg/L and tylosin tartarate at 1.25 mg/L). Cultures also had 0 or 1.75 mg of S/L (from sodium sulfate). No S x ionophore-antibiotic treatment interactions were noted (P > 0.53) for IVDMD, total gas production, and H(2)S production. Hydrogen sulfide (mumol/g of fermentable DM) was increased (P ionophores or antibiotics (P > 0.18). On average, IVDMD (P = 0.05) was greater for ionophores than for antibiotics, whereas total gas production was less for ionophores than for control (P ionophore treatments when no S was added, but when S was added there were no differences (P > 0.20) in acetate, propionate, or acetate:propionate between ionophores and control (S x treatment interaction, P = 0.03). In Exp. 2, the effects of ionophore-antibiotic combinations with added S were examined using the same procedures as in Exp. 1. Treatments were control, monensin plus tylosin (MT), and lasalocid plus chlortetracycline (LCTC), with concentrations of the ionophores and antibiotics as in Exp. 1. No differences were observed among treatments for H(2)S production (P > 0.55). Treatments MT and LCTC tended (P = 0.06) to increase IVDMD and decreased (P = 0.02) gas production vs. control. Proportion of acetate (P = 0.01) and acetate:propionate (P ionophores and 2 antibiotics we evaluated did not affect production of H(2)S gas in an in vitro rumen culture system.

  17. Transduction of selective recognition by preorganized ionophores, K$#+$# selectivity of the different 1,3-diethoxycalix[4]arene crown ether conformers

    NARCIS (Netherlands)

    Brzozka, Zbigniew; Lammerink, Ben; Reinhoudt, David; Ghidini, Eleonora; Ungaro, Rocco

    1993-01-01

    Three different conformers of 1,3-diethoxy-p-tert-butylcalix[4]arene crown ethers have been used to study the effect of the ionophore preorganization on the potentiometric K+-selectivity. Selectivities were measured for chemically modified field effect transistors (CHEMFETs) and membrane

  18. Synthesis of a new family of ionophores based on aluminum-dipyrrin complexes (ALDIPYs) and their strong recognition of alkaline earth ions.

    Science.gov (United States)

    Saikawa, Makoto; Daicho, Manami; Nakamura, Takashi; Uchida, Junji; Yamamura, Masaki; Nabeshima, Tatsuya

    2016-03-14

    Mononuclear and dinuclear aluminum-dipyrrin complexes (ALDIPYs) were synthesized as a new family of ionophores. They exhibited colorimetric and fluorometric responses to alkaline earth ions in an aqueous mixed solvent. The strong recognition was achieved via multipoint interactions with the oxygen atoms appropriately incorporated into the ligand framework.

  19. Substitutions in Calcium Aluminates and Calcium Aluminoferrites.

    Science.gov (United States)

    ALUMINUM COMPOUNDS, *CEMENTS, * CALCIUM COMPOUNDS, * FERRITES , *SCIENTIFIC RESEARCH, INFRARED SPECTROSCOPY, X RAY DIFFRACTION, CHEMICAL COMPOSITION, SUBSTITUTES, CHEMICAL ANALYSIS, ALKALI METAL COMPOUNDS.

  20. Determination of ionophore coccidiostat salinomycine in premixes and poultry feeding stuffs by liquid chromatography after post-column derivatisation

    Directory of Open Access Journals (Sweden)

    Kostadinović Ljiljana M.

    2014-01-01

    Full Text Available Coccidiosis is a common parasitic disease of broiler chickens caused by single-celled protozoan parasites of the genus Eimeria which are commonly referred to as coccidian. This is an infective disease of the digestive tract which is most frequent with poultry, causing a decrease in daily increment, prolonged fattening, poorer skin pigmentation, slower feed conversion and increased mortality. The disease is caused by Protozoas from the genera of Eimeria, Isospora and Cryptospora, and it is manifested by damaging the intestine epithelial cells, less frequently the bile duct and renal tubuli. Coccidiosis is traditionally controlled by chemotherapy. There are many anticoccidial preparations which are used in the prevention of coccidiosis. We are chose a polyether monocarboxylic acid - salinomycine. Salinomycin is monovalent carboxyl-polyether ionophores. Salinomycin, produced by Streptomyces albus, destroys the cell membranes and causes their lysis. Salinomycin and other ionophoric antibiotics combine with a number of mono and divalent cations and in the form of bi-complexes make it possible to transfer metal ions through lipid hydrophobic membrane, and when they are added to diet, they change bioavailability, gut uptake and absorption and reserves of nutrient tissues. In this paper has been developed and validated process of Liquid chromatography determination of ionophoric coccidiostat salinomycin with UV spectrophotometric detection and post-column derivatisation with dimethylaminobenzaldehyde (DMAB. The method is based on extraction of salinomycin in animal feed samples using mixture acetonitrile-water (80:20, v/v and purification of extracts obtained by the filter 0,2 μm Acrodisc® PSF. The relative standard deviation (RSD for reproducibility and accuracy varied from 2,4 to 8,8% and from 2,6% to 8,8%, respectively and the values for the relative recovery rate ranged from 89 to 98%. The limit of detection (LOD and limit of quantification (LOQ

  1. A Solid-Contact Ion Selective Electrode for Copper(II Using a Succinimide Derivative as Ionophore

    Directory of Open Access Journals (Sweden)

    Mihaela Dana Tutulea-Anastasiu

    2013-04-01

    Full Text Available All-solid-state sensors with polyvinyl chloride (PVC-based membranes using off-the-shelf N-hydroxysuccinimide (NHS and succinimide (Succ ionophores were prepared using DOP (dioctyl phthalate and NPOE (ortho-nitrophenyloctyl ether as plasticizers. Good responses were obtained when NHS was used. The potentiometric response of the proposed electrode is independent of pH over the range 2–6. The electrode shows a fast response time of 0.25 s. The electrode exhibits a Super-Nernstian response, with 37.5 mV/decade, with a potentiometric detection limit of 4.4 µM. The proposed sensor revealed good selectivity towards a group of transition metal ions.

  2. New 8-hydroxyquinoline galactosides. The role of the sugar in the antiproliferative activity of copper(II) ionophores.

    Science.gov (United States)

    Oliveri, Valentina; Viale, Maurizio; Aiello, Cinzia; Vecchio, Graziella

    2015-01-01

    8-Hydroxyquinoline derivatives and their metal complexes have recently awakened interest as promising therapeutic agents in cancer therapy. We have previously synthesized and evaluated glucoconjugated 8-hydroxyquinolines as copper ionophores activated by β-glucosidases. In order to further evaluate the crucial role of the sugar, we designed and synthesized a series of new galactoconjugates of 8-hydroxyquinolines and investigated their biological properties in comparison with the 8-hydroxyquinoline analogs. The effect of copper(II) ions on their biological activities was evaluated. In particular, two compounds possess a pharmacologically relevant antiproliferative activity against specific tumor cells in the presence of copper(II) ions. Furthermore, the antiproliferative activity of the selected galactosides was successfully investigated in the presence of β-galactosidase as a preliminary model of antibody directed enzyme prodrug therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Comparative studies of mercapto thiadiazoles self-assembled on gold nanoparticle as ionophores for Cu(II) carbon paste sensors

    Energy Technology Data Exchange (ETDEWEB)

    Mashhadizadeh, Mohammad Hossein, E-mail: mashhadizadeh@yahoo.com [Faculty of Chemistry, Tarbiat Moallem University, Tehran (Iran, Islamic Republic of); Khani, Hadi [Faculty of Chemistry, Tarbiat Moallem University, Tehran (Iran, Islamic Republic of); Foroumadi, Alireza [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14174 (Iran, Islamic Republic of); Sagharichi, Parishad [Faculty of Chemistry, Tarbiat Moallem University, Tehran (Iran, Islamic Republic of)

    2010-04-30

    Comparative studies of the potentiometric behavior of three mercapto compounds [2-((5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl)phenol] (MTMP), [5-(2-methoxy benzylidene amino)-1,3,4-thiadiazole-2-thiol] (MBYT) and [5-(pyridin-2-ylmethyleneamino)-1,3,4-thiadiazole-2-thiol] (PYTT) self-assembled on gold nanoparticles (GNPs) as ionophores in carbon paste electrodes (CPEs) have been made. These mercapto thiadiazole compounds were self-assembled onto gold nanoparticles and then incorporated within carbon paste electrode. The self-assembled ionophores exhibit a high selectivity for copper ion (Cu{sup 2+}), in which the sulfur and nitrogen atoms in their structure play a role as the effective coordination donor site for the copper ion. These carbon paste electrodes were applied as indicator electrodes for potentiometric determination of copper ions. The sensor based on PYTT exhibits the working concentration range of 4.0 x 10{sup -9} to 7.0 x 10{sup -2} M and a Nernstian slope of 28.7 {+-} 0.3 mV decade{sup -1} of copper activity. The detection limit of electrode was 1.0 x 10{sup -9} M and potential response was pH independent across the range of 3.0-6.5. It exhibited a quick response time of <5 s and could be used for a period of 45 days. The ion selectivity of this electrode for Cu{sup 2+} was over 10{sup 4} times that for other metal cations. The application of prepared sensors has been demonstrated for the determination of copper ions in spiked water and natural water samples.

  4. Potentiometric Response Characteristics of Membrane-Based Cs+-Selective Electrodes Containing Ionophore-Functionalized Polymeric Microspheres

    Directory of Open Access Journals (Sweden)

    Shane Peper

    2011-01-01

    Full Text Available Cs+-selective solvent polymeric membrane-based ion-selective electrodes (ISEs were developed by doping ethylene glycol-functionalized cross-linked polystyrene microspheres (P-EG into a plasticized poly(vinyl chloride (PVC matrix containing sodium tetrakis-(3,5-bis(trifluoromethylphenyl borate (TFPB as the ion exchanger. A systematic study examining the effects of the membrane plasticizers bis(2-ethylhexyl sebacate (DOS, 2-nitrophenyl octyl ether (NPOE, and 2-fluorophenyl nitrophenyl ether (FPNPE on the potentiometric response and selectivity of the corresponding electrodes was performed. Under certain conditions, P-EG-based ion-selective electrodes (ISEs containing TFPB and plasticized with NPOE exhibited a super-Nernstian response between 1×10−3 and 1×10−4 M Cs+, a response characteristic not observed in analogous membranes plasticized with either DOS or FPNPE. Additionally, the performance of P-EG-based ISEs was compared to electrodes based on two mobile ionophores, a neutral lipophilic ethylene glycol derivative (ethylene glycol monooctadecyl ether (U-EG and a charged metallacarborane ionophore, sodium bis(dicarbollylcobaltate(III (CC. In general, P-EG-based electrodes plasticized with FPNPE yielded the best performance, with a linear range from 10-1–10-5 M Cs+, a conventional lower detection limit of 8.1×10−6 M Cs+, and a response slope of 57.7 mV/decade. The pH response of P-EG ISEs containing TFPB was evaluated for membranes plasticized with either NPOE or FPNPE. In both cases, the electrodes remained stable throughout the pH range 3–12, with only slight proton interference observed below pH 3.

  5. Rapid method for the simultaneous determination of six ionophores in feed by liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Vudathala, Daljit; Murphy, Lisa

    2012-01-01

    A simple and highly sensitive LC/MS method was developed for the simultaneous determination of six ionophores--lasalocid, monensin, laidlomycin, maduramycin, salinomycin, and narasin--in feed. The procedure involved extraction of 1 g of feed with 4 mL of methanol-water (9 + 1, v/v) by shaking on a platform shaker for 45 min. After centrifugation, the extracts were diluted with methanol-water (75 + 25, v/v) and analyzed without any cleanup. The analysis was performed on a Betasil C18 column (150 x 4.6 mm id, 5 pm particle size) connected to an LC/MS system operated in the atmospheric pressure chemical ionization (APCI) mode. We believe this to be the first method that uses the APCI mode for the analysis of ionophores. The mobile phase consisted of 50 mM ammonium acetate as solvent A and acetonitrile-methanol (7 + 3, v/v) as solvent B in a gradient run. Excellent recoveries of 81-120% were found for all compounds at fortification levels of 1-200 microg/g, with RSD < or =15% (except 17% for maduramycin at 2 and 5 microg/g, and 16% for salinomycin at 1 microg/g). At 0.5 microg/g, recoveries of 87-119% were obtained, with RSD < or =20%. However, recovery of lasalocid was 133% and salinomycin 79% in sow and horse feed, respectively. Average RSD values of lasalocid and salinomycin were 22 and 21%, respectively. Finally, proficiency test samples analyzed with the method demonstrated favorable agreement with the certified values.

  6. Comparative studies of mercapto thiadiazoles self-assembled on gold nanoparticle as ionophores for Cu(II) carbon paste sensors.

    Science.gov (United States)

    Mashhadizadeh, Mohammad Hossein; Khani, Hadi; Foroumadi, Alireza; Sagharichi, Parishad

    2010-04-30

    Comparative studies of the potentiometric behavior of three mercapto compounds [2-((5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl)phenol] (MTMP), [5-(2-methoxy benzylidene amino)-1,3,4-thiadiazole-2-thiol] (MBYT) and [5-(pyridin-2-ylmethyleneamino)-1,3,4-thiadiazole-2-thiol] (PYTT) self-assembled on gold nanoparticles (GNPs) as ionophores in carbon paste electrodes (CPEs) have been made. These mercapto thiadiazole compounds were self-assembled onto gold nanoparticles and then incorporated within carbon paste electrode. The self-assembled ionophores exhibit a high selectivity for copper ion (Cu(2+)), in which the sulfur and nitrogen atoms in their structure play a role as the effective coordination donor site for the copper ion. These carbon paste electrodes were applied as indicator electrodes for potentiometric determination of copper ions. The sensor based on PYTT exhibits the working concentration range of 4.0 x 10(-9) to 7.0 x 10(-2) M and a Nernstian slope of 28.7+/-0.3 mV decade(-1) of copper activity. The detection limit of electrode was 1.0 x 10(-9) M and potential response was pH independent across the range of 3.0-6.5. It exhibited a quick response time of <5 s and could be used for a period of 45 days. The ion selectivity of this electrode for Cu(2+) was over 10(4) times that for other metal cations. The application of prepared sensors has been demonstrated for the determination of copper ions in spiked water and natural water samples. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Calcium channel blocker overdose

    Science.gov (United States)

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

  8. Fenoprofen calcium overdose

    Science.gov (United States)

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

  9. The Role of IQGAP1 in Breast Carcinoma

    Science.gov (United States)

    2010-01-10

    widely used methods to manipulate [Ca2+]i. A23187 is a Ca2+ ionophore that causes a rapid and sustained increase in [Ca2+]i by permitting entry into...dilution to 5 ng/ml in DMEM supplemented with 1% PSG and 1 mM HEPES. 2. A23187 is a selective Ca2+ ionophore (10). It greatly increases the ability...tions of ionophores . Annu Rev Biochem 45, 501–30. 8/25/10 11:30 AMIQGAP1 is a Novel HER2 Binding Partner and Regulates HER2-Mediated Cell Proliferation

  10. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

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

  11. Calcium en cardioplegie

    NARCIS (Netherlands)

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

    1985-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-05-01

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

  13. MARCKS Protein Is Phosphorylated and Regulates Calcium Mobilization during Human Acrosomal Exocytosis

    Science.gov (United States)

    Rodriguez Peña, Marcelo J.; Castillo Bennett, Jimena V.; Soler, Osvaldo M.; Mayorga, Luis S.; Michaut, Marcela A.

    2013-01-01

    Acrosomal exocytosis is a calcium-regulated exocytosis that can be triggered by PKC activators. The involvement of PKC in acrosomal exocytosis has not been fully elucidated, and it is unknown if MARCKS, the major substrate for PKC, participates in this exocytosis. Here, we report that MARCKS is expressed in human spermatozoa and localizes to the sperm head and the tail. Calcium- and phorbol ester-triggered acrosomal exocytosis in permeabilized sperm was abrogated by different anti-MARCKS antibodies raised against two different domains, indicating that the protein participates in acrosomal exocytosis. Interestingly, an anti-phosphorylated MARCKS antibody was not able to inhibit secretion. Similar results were obtained using recombinant proteins and phospho-mutants of MARCKS effector domain (ED), indicating that phosphorylation regulates MARCKS function in acrosomal exocytosis. It is known that unphosphorylated MARCKS sequesters PIP2. This phospholipid is the precursor for IP3, which in turn triggers release of calcium from the acrosome during acrosomal exocytosis. We found that PIP2 and adenophostin, a potent IP3-receptor agonist, rescued MARCKS inhibition in permeabilized sperm, suggesting that MARCKS inhibits acrosomal exocytosis by sequestering PIP2 and, indirectly, MARCKS regulates the intracellular calcium mobilization. In non-permeabilized sperm, a permeable peptide of MARCKS ED also inhibited acrosomal exocytosis when stimulated by a natural agonist such as progesterone, and pharmacological inducers such as calcium ionophore and phorbol ester. The preincubation of human sperm with the permeable MARCKS ED abolished the increase in calcium levels caused by progesterone, demonstrating that MARCKS regulates calcium mobilization. In addition, the phosphorylation of MARCKS increased during acrosomal exocytosis stimulated by the same activators. Altogether, these results show that MARCKS is a negative modulator of the acrosomal exocytosis, probably by sequestering

  14. Effect of π electrons on the detection of silver ions by ion-selective electrodes containing tripodal broom molecules as an ionophore.

    Science.gov (United States)

    Yamamoto, Chihiro; Seto, Hirokazu; Ohto, Keisuke; Kawakita, Hidetaka; Harada, Hiroyuki

    2011-01-01

    Tripodal "broom" molecule derivatives containing π electrons were used as ionophores of silver ion-selective electrodes. The ability of the electrodes to detect silver ions was evaluated using the Nernst equation. When allyl- and propargyl-type tripodal broom molecules, and a propargyl-type monopodal analog were used in the electrode, Nernstian responses for silver ions were observed, indicating that π electrons play an important role in the detection of silver ions. In the presence of interfering metal ions, the selectivity for silver ions was affected by the number and density of π electrons in the ionophore. The electrode containing the allyl-type tripodal broom molecule was used to accurately determine the concentration of glucosamine hydrochloride in a real sample.

  15. Large volume injection for the direct analysis of ionophores and avermectins in surface water by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Thompson, T S; Noot, D K; Forrest, F; van den Heever, J P; Kendall, J; Keenliside, J

    2009-02-02

    A simple method for the direct determination of residues of ionophore antibiotics and avermectin antiparasitics in surface water is reported. Using a large volume injector, a mixture of methanol and surface water is injected into an analytical liquid chromatography (LC) column and subsequently screened for residues of these veterinary pharmaceuticals using electrospray ionization tandem mass spectrometry. On-line sample enrichment and chromatographic separation are achieved using a single, short (20mm) octadecylsilane LC column. The method permits the detection of four ionophores and two avermectins in surface water samples at low ng L(-1) concentrations. Minimal matrix effects were observed for a variety of surface water samples which permitted the use of reagent-based standards for quantitation.

  16. Pilot survey of hen eggs consumed in the metropolitan area of Rio de Janeiro, Brazil, for polyether ionophores, macrolides and lincosamides residues.

    Science.gov (United States)

    Spisso, Bernardete Ferraz; Pereira, Mararlene Ulberg; Ferreira, Rosana Gomes; Monteiro, Mychelle Alves; da Costa, Rafaela Pinto; Cruz, Tatiana Ávila; da Nóbrega, Armi Wanderley

    2010-01-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, which has recently been developed and validated, was used for the identification and quantification of polyether ionophore, macrolide and lincosamide residues in commercial eggs sold in the metropolitan area of Rio de Janeiro, Brazil. The method was applied to 100 samples and the results showed a high incidence of polyether ionophore residues (25%). Salinomycin was detected in 21% of samples, but only two non-compliant results (5.3 and 53 µg kg(-1)) were found if maximum limits (tolerances) established by European Union were adopted in Brazil and if a method decision limit (CCα) of 3.4 µg kg(-1) was considered. In 8% of analyzed samples, more than one studied coccidiostat was found. The lincosamide, lincomycin, and the macrolide, tylosin, were detected at trace levels in 4 and 1% of the samples, respectively. Lasalocid, clarithromycin and erythromycin were not found.

  17. ERK activation by Ca2+ ionophores depends on Ca2+ entry in lymphocytes but not in platelets, and does not conduct membrane scrambling.

    Science.gov (United States)

    Arachiche, A; Badirou, I; Dachary-Prigent, J; Garcin, I; Geldwerth-Feniger, D; Kerbiriou-Nabias, D

    2008-11-01

    Rapid Ca2+-dependent phospholipid (PL) reorganization (scrambling) at the plasma membrane is a mechanism common to hematopoietic cells exposing procoagulant phosphatidylserine (PS). The aim of this research was to determine whether activation of the extracellular signal-regulated kinase (ERK) pathway was required for PL scrambling, based on a single report analyzing both responses induced by Ca2+ ionophores in megakaryoblastic HEL cells. Ca2+ ionophore-stimulated ERK phosphorylation was induced in platelets without external Ca2+, whereas exogenous Ca2+ entry was crucial for ERK activation in Jurkat T cells. In both cells, membrane scrambling only occurred following Ca2+ entry and was not blocked by inhibiting ERK phosphorylation. Furthermore, ERK proteins are strongly phosphorylated in transformed B lymphoblastic cell lines, which do not expose PS in their resting state. Overall, the data demonstrated that ERK activation and membrane scrambling are independent mechanisms.

  18. Highly Selective Detection of Silver in the Low ppt Range with Ion-Selective Electrodes Based on Ionophore-Doped Fluorous Membranes

    Science.gov (United States)

    Lai, Chun-Ze; Fierke, Melissa A.; Costa, Rosenildo Corrêa da; Gladysz, John A.; Stein, Andreas; Bühlmann, Philippe

    2010-01-01

    Ionophore-doped sensing membranes exhibit greater selectivities and wider measuring ranges if their membrane matrixes are noncoordinating and solvate interfering ions poorly. This is particularly true for fluorous phases, which are the least polar and polarizable condensed phases known. In this work, fluorous membrane matrixes were used to prepare silver ion-selective electrodes (ISEs). Sensing membranes composed of perfluoroperhydrophenanthrene, sodium tetrakis[3,5-bis(perfluorohexyl)phenyl]borate, and one of four fluorophilic Ag+-selective ionophores with one or two thioether groups were investigated. All electrodes exhibited Nernstian responses to Ag+ in a wide range of concentrations. Their selectivities for Ag+ over interfering ions were found to depend on host preorganization and the length of the –(CH2)n– spacers separating the coordinating thioether group from the strongly electron withdrawing perfluoroalkyl groups. ISEs based on the most selective of the four ionophores, i.e., 1,3-bis(perfluorodecylethylthiomethyl)benzene, provided much higher selectivities for Ag+ over many alkaline and heavy metal ions than most Ag+ ISEs reported in the literature (e.g., logKAg,Jpot for K+, −11.6; Pb2+, −10.2; Cu2+, −13.0; Cd2+, −13.2). Moreover, the use of this ionophore with a linear perfluorooligoether as membrane matrix and solid contacts consisting of three-dimensionally ordered macroporous (3DOM) carbon resulted in a detection limit for Ag+ of 4.1 ppt (3.8×10−11 M). PMID:20799720

  19. Comparative study of 2-hydroxy propyl beta cyclodextrin and calixarene as ionophores in potentiometric ion-selective electrodes for neostigmine bromide.

    Science.gov (United States)

    El-Kosasy, Amira M; Nebsen, Marianne; Abd El-Rahman, Mohamed K; Salem, Maissa Y; El-Bardicy, Mohamed G

    2011-08-15

    Three novel neostigmine bromide (NEO) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using tetrakis(4-chlorophenyl)borate (TpClPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor 3 was constructed using 4-sulfocalix-8-arene as an ionophore. Linear responses of NEO within the concentration ranges of 10(-5) to 10(-2), 10(-6) to 10(-2) and 10(-7) to 10(-2) mol L(-1) were obtained using sensors 1, 2 and 3, respectively. Nernstian slopes of 51.6 ± 0.8, 52.9 ± 0.6 and 58.6 ± 0.4 mV/decade over the pH range of 4-9 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for NEO. The utility of 2-hydroxy propyl β-cyclodextrin and 4-sulfocalix[8]arene as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2 and 3 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of NEO in bulk powder, different pharmaceutical formulations, and biological fluids (plasma and cerebrospinal fluid (CSF)) and in the presence of its degradation product (3-hydroxyphenyltrimethyl ammonium bromide) and thus could be used for stability-indicating methods. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Polymeric optical sensors for selective and sensitive nitrite detection using cobalt(III) corrole and rhodium(III) porphyrin as ionophores

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Si; Wo, Yaqi; Meyerhoff, Mark E., E-mail: mmeyerho@umich.edu

    2014-09-16

    Highlights: • We examine cobalt(III) corroles and rhodium(III) porphyrins as ionophores in polymeric films for optical sensors to detect nitrite. • Different types of proton chromoionophores are evaluated to optimize nitrite response. • Selectivity over lipophilic anions such as perchlorate and thiocyanate is observed. • Both ionophores yield optical sensors that are fully reversible. • The cobalt(III) corrole based sensor is employed to determine nitric oxide emission rates from NO donor doped polymers with good accuracy. - Abstract: Cobalt(III) 5,10,15-tris(4-tert-butylphenyl) corrole with a triphenylphosphine axial ligand and rhodium(III) 5,10,15,20-tetra(p-tert-butylphenyl) porphyrin are incorporated into plasticized poly(vinyl chloride) films to fabricate nitrite-selective bulk optodes via absorbance measurements. The resulting films yield sensitive, fast and fully reversible response toward nitrite with significantly enhanced nitrite selectivity over other anions including lipophilic anions such as thiocyanate and perchlorate. The selectivity patterns differ greatly from the Hofmeister series based on anion lipophilicity and are consistent with selectivity obtained with potentiometric sensors based on the same ionophores. The optical nitrite sensors are shown to be useful for detecting rates of emission of nitric oxide (NO) from NO releasing polymers containing S-nitroso-N-acetyl-DL-penicillamine.

  1. Calcium channel blocker poisoning

    Directory of Open Access Journals (Sweden)

    Miran Brvar

    2005-04-01

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

  2. Zinc ionophores pyrithione inhibits herpes simplex virus replication through interfering with proteasome function and NF-κB activation.

    Science.gov (United States)

    Qiu, Min; Chen, Yu; Chu, Ying; Song, Siwei; Yang, Na; Gao, Jie; Wu, Zhiwei

    2013-10-01

    Pyrithione (PT), known as a zinc ionophore, is effective against several pathogens from the Streptococcus and Staphylococcus genera. The antiviral activity of PT was also reported against a number of RNA viruses. In this paper, we showed that PT could effectively inhibit herpes simplex virus types 1 and 2 (HSV-1 and HSV-2). PT inhibited HSV late gene (Glycoprotein D, gD) expression and the production of viral progeny, and this action was dependent on Zn(2+). Further studies showed that PT suppressed the expression of HSV immediate early (IE) gene, the infected cell polypeptide 4 (ICP4), but had less effect on another regulatory IE protein, ICP0. It was found that PT treatment could interfere with cellular ubiquitin-proteasome system (UPS), leading to the inhibition of HSV-2-induced IκB-α degradation to inhibit NF-κB activation and enhanced promyelocytic leukemia protein (PML) stability in nucleus. However, PT did not show direct inhibition of 26S proteasome activity. Instead, it induced Zn(2+) influx, which facilitated the dysregulation of UPS and the accumulation of intracellular ubiquitin-conjugates. UPS inhibition by PT caused disruption of IκB-α degradation and NF-κB activation thus leading to marked reduction of viral titer. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Copper binding agents acting as copper ionophores lead to caspase inhibition and paraptotic cell death in human cancer cells.

    Science.gov (United States)

    Tardito, Saverio; Bassanetti, Irene; Bignardi, Chiara; Elviri, Lisa; Tegoni, Matteo; Mucchino, Claudio; Bussolati, Ovidio; Franchi-Gazzola, Renata; Marchiò, Luciano

    2011-04-27

    We report a quantitative structure-activity relationship study of a new class of pyrazole-pyridine copper complexes that establishes a clear correlation between the ability to promote copper accumulation and cytotoxicity. Intracellular metal accumulation is maximized when ligand lipophilicity allows the complex to rapidly cross the membrane. Copper and ligand follow different uptake kinetics and reach different intracellular equilibrium concentrations. These results support a model in which the ligand acts as an ionophore for the metal ion, cycling between intra- and extracellular compartments as dissociated or complexed entities. When treating cancer cells with structurally unrelated disulfiram and pyrazole-pyridine copper complexes, as well as with inorganic copper, the same morphological and molecular changes were reproduced, indicating that copper overload is responsible for the cytotoxic effects. Copper-based treatments drive sensitive cancer cells toward paraptotic cell death, a process hallmarked by endoplasmic reticulum stress and massive vacuolization in the absence of apoptotic features. A lack of caspase activation, as observed in copper-treated dying cells, is a consequence of metal-mediated inhibition of caspase-3. Thus, copper acts simultaneously as an endoplasmic reticulum (ER) stress inducer and a caspase-3 inhibitor, forcing the cell into caspase-independent paraptotic death. The establishment of a mechanism of action common to different copper binding agents provides a rationale for the exploitation of copper toxicity as an anticancer tool.

  4. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  5. Calcium and bones

    Science.gov (United States)

    ... eat in their diet. Vitamin D is the hormone that helps the gut absorb more calcium. Many older adults have common risks that make bone health worse. Calcium intake in the diet (milk, cheese, yogurt) is low. Vitamin D levels are ...

  6. Calcium D-saccharate

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  7. Extracellular Calcium and Magnesium

    African Journals Online (AJOL)

    ABSTRACT. The cause of preeclampsia remains unknown and calcium and magnesium supplement are being suggested as means of prevention. The objective of this study was to assess magnesium and calcium in the plasma and cerebrospinal fluid of Nigerian women with preedamp sia and eclampsia. Setting was ...

  8. SUMO-Modified FADD Recruits Cytosolic Drp1 and Caspase-10 to Mitochondria for Regulated Necrosis.

    Science.gov (United States)

    Choi, Seon-Guk; Kim, Hyunjoo; Jeong, Eun Il; Lee, Ho-June; Park, Sungwoo; Lee, Song-Yi; Lee, Hyeon-Jeong; Lee, Seong Won; Chung, Chin Ha; Jung, Yong-Keun

    2017-01-15

    Fas-associated protein with death domain (FADD) plays a key role in extrinsic apoptosis. Here, we show that FADD is SUMOylated as an essential step during intrinsic necrosis. FADD was modified at multiple lysine residues (K120/125/149) by small ubiquitin-related modifier 2 (SUMO2) during necrosis caused by calcium ionophore A23187 and by ischemic damage. SUMOylated FADD bound to dynamin-related protein 1 (Drp1) in cells both in vitro and in ischemic tissue damage cores, thus promoting Drp1 recruitment by mitochondrial fission factor (Mff) to accomplish mitochondrial fragmentation. Mitochondrial-fragmentation-associated necrosis was blocked by FADD or Drp1 deficiency and SUMO-defective FADD expression. Interestingly, caspase-10, but not caspase-8, formed a ternary protein complex with SUMO-FADD/Drp1 on the mitochondria upon exposure to A23187 and potentiated Drp1 oligomerization for necrosis. Moreover, the caspase-10 L285F and A414V mutants, found in autoimmune lymphoproliferative syndrome and non-Hodgkin lymphoma, respectively, regulated this necrosis. Our study reveals an essential role of SUMOylated FADD in Drp1- and caspase-10-dependent necrosis, providing insights into the mechanism of regulated necrosis by calcium overload and ischemic injury. Copyright © 2017 American Society for Microbiology.

  9. The mechanism of action of dantrolene sodium.

    Science.gov (United States)

    Morgan, K G; Bryant, S H

    1977-04-01

    Dantrolene sodium is thought to affect some step in the excitation-contraction coupling process. Using a point voltage clamp to determine mechanical thresholds of individual fibers of frog, rat and goat skeletal muscle preparations, we found that dantrolene both raises (moves to more positive potentials) the rheobasic potential and increases the steepness of the strength-duration curve for mechanical threshold. The effect of raising the rheobase reaches a maximum at 1.2 x 10-5M dantrolene whereas the steepness effect occurs only at a saturating concentration (3.8x10-5M),indicating that dantrolene has two sites of action. The rheobase effect is absent below 18 degrees C (suggesting a phase transition) and it is competitively antagnoized by the calcium ionophore A23187 which can release calcium from the sarcoplasmic reticulum. The data indicate that dantrolene raises the rheobase by directly decreasing the release of calcium from the sarcoplasmic reticulum. We propose that dantrolene inhibits the movement of a natural calcium ionophore. Measurements of the voltage-dependent charge movement associated with excitation-contraction coupling showed that dantrolene did not significantly change the amount of charge moved. The time to peak of the ON current was not significantly changed, but that of the OFF current was significantly shortened. This action of dantrolene on the kinetics of the OFF current may account for its effect on the steepness of the strength-duration curve.

  10. Kinetics and modeling of degradation of ionophore antibiotics by UV and UV/H2O2.

    Science.gov (United States)

    Yao, Hong; Sun, Peizhe; Minakata, Daisuke; Crittenden, John C; Huang, Ching-Hua

    2013-05-07

    Ionophore antibiotics (IPAs), one of the major groups of pharmaceuticals used in livestock industry, have been found to contaminate agricultural runoff and surface waters via land application of animal manures as fertilizers. However, limited research has investigated the means to remove IPAs from water sources. This study investigates the degradation of IPAs by using ultraviolet (UV) photolysis and UV combined with hydrogen peroxide (UV/H2O2) advanced oxidation process (AOP) under low-pressure (LP) UV lamps in various water matrices. Three widely used (monensin, salinomycin, and narasin) and one model (nigericin) IPAs exhibit low light absorption in the UV range and degrade slowly at the light intensity of 3.36 × 10(-6) Einstein·L(-1)·s(-1) under UV photolysis conditions. However, IPAs react with hydroxyl radicals produced by UV/H2O2 at fast reaction rates, with second-order reaction rate constants at (3.49-4.00) × 10(9) M(-1)·s(-1). Water matrix constituents enhanced the removal of IPAs by UV photolysis but inhibited UV/H2O2 process. A steady-state kinetic model successfully predicts the impact of water constituents on IPA degradation by UV/H2O2 and determines the optimal H2O2 dose by considering both energy consumption and IPA removal. LC/MS analysis of reaction products reveals the initial transformation pathways of IPAs via hydrogen atom abstraction and peroxidation during UV/H2O2. This study is among the first to provide a comprehensive understanding of the degradation of IPAs via UV/H2O2 AOP.

  11. Metal ionophore treatment restores dendritic spine density and synaptic protein levels in a mouse model of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Paul A Adlard

    Full Text Available We have previously demonstrated that brief treatment of APP transgenic mice with metal ionophores (PBT2, Prana Biotechnology rapidly and markedly improves learning and memory. To understand the potential mechanisms of action underlying this phenomenon we examined hippocampal dendritic spine density, and the levels of key proteins involved in learning and memory, in young (4 months and old (14 months female Tg2576 mice following brief (11 days oral treatment with PBT2 (30 mg/kg/d. Transgenic mice exhibited deficits in spine density compared to littermate controls that were significantly rescued by PBT2 treatment in both the young (+17%, p<0.001 and old (+32%, p<0.001 animals. There was no effect of PBT2 on spine density in the control animals. In the transgenic animals, PBT2 treatment also resulted in significant increases in brain levels of CamKII (+57%, p = 0.005, spinophilin (+37%, p = 0.04, NMDAR1A (+126%, p = 0.02, NMDAR2A (+70%, p = 0.05, pro-BDNF (+19%, p = 0.02 and BDNF (+19%, p = 0.04. While PBT2-treatment did not significantly alter neurite-length in vivo, it did increase neurite outgrowth (+200%, p = 0.006 in cultured cells, and this was abolished by co-incubation with the transition metal chelator, diamsar. These data suggest that PBT2 may affect multiple aspects of snaptic health/efficacy. In Alzheimer's disease therefore, PBT2 may restore the uptake of physiological metal ions trapped within extracellular β-amyloid aggregates that then induce biochemical and anatomical changes to improve cognitive function.

  12. Ion-Selective Electrode for Anionic Surfactants Using Hexadecyl Trimethyl Ammonium Bromide-Sodium Dodecylsulfate as an Active Ionophore

    Directory of Open Access Journals (Sweden)

    Junwei Wang

    2011-01-01

    Full Text Available The construction and characteristic performance of PVC membrane electrode responsive to sodium dodecylsulfate (SDS are described in this paper. The electrode is based on hexadecyl trimethyl ammonium bromide-Sodium dodecylsulfate (CTA+DS− ion pair as ionophore in PVC membrane, which displays a Nernstian slope of −58 ± 0.9 mV/decade in a 5.0 × 10−6 to 2.5 × 10−3 mol L−1 concentration range and a limit of detection of 2.9 × 10−6 mol L−1. The electrode can be used for 3 months without showing significant changes in the value of slope or working range. Also the electrode has wide pH range of application and short response time. The electrode shows a selective response to SDS and a poor response to common inorganic anions. The selective sequence found was SDS > HCO3 − > CH3COO− > Cl− > I− > NO3 −≈ Br− > F− > CO3 2− > C6H5O7 3− > C2O4 2− > SO4 2− > C4H4O6 2− > SO3 2− > PO4 3−. The potentiometric selectivity coefficients determined are indicating that common anions would not interfere in the SDS determination. The electrode has been utilized as an end point indicator electrode for potentiometric titration involving hyamine as titrant.

  13. Weak bases and ionophores rapidly and reversibly raise the pH of endocytic vesicles in cultured mouse fibroblasts

    Science.gov (United States)

    1982-01-01

    It has been shown that endocytic vesicles in BALB/c 3T3 cells have a pH of 5.0 (Tycko and Maxfield, Cell, 28:643-651). In this paper, a method for measuring the effect of various agents, including weak bases and ionophores, on the pH of endocytic vesicles is presented. The method is based on the increase in fluorescein fluorescence with 490-nm excitation as the pH is raised above 5.0. Intensities of cells were measured using a microscope spectrofluorometer after internalization of fluorescein-labeled alpha 2-macroglobulin by receptor-mediated endocytosis. The increase in endocytic vesicle pH was determined from the increase in fluorescence after addition of various concentrations of the test agents. The following agents increased endocytic vesicle pH above 6.0 at the indicated concentrations: monensin (6 microM), FCCP (10 microM), chloroquine (140 microM), ammonia (5 mM), methylamine (10 mM). The ability of many of these agents to raise endocytic vesicle pH may account for many of their effects on receptor-mediated endocytosis. Dansylcadaverine caused no effect on vesicle pH at 1 mM. The observed increases in vesicle pH were rapid (1-2 min) and could be reversed by removal of the perturbant. This reversibility indicates that the vesicles themselves contain a mechanism for acidification. The increase in vesicle pH due to these treatments can be observed visually using an SIT video camera. Using this method, it is shown that endocytic vesicles become acidic at very early times (i.e., within 5-7 min of continuous uptake at 37 degrees C). PMID:6183281

  14. Steroid modulation of the chloride ionophore in rat brain: structure-activity requirements, regional dependence and mechanism of action

    Energy Technology Data Exchange (ETDEWEB)

    Gee, K.W.; Bolger, M.B.; Brinton, R.E.; Coirini, H.; McEwen, B.S.

    1988-08-01

    Further in vitro studies of steroids active at the gamma-aminobutyric acidA (GABAA) receptor regulated Cl- channel labeled by (35S)-t-butylbicyclophosphorothionate ((35S)TBPS) reveal additional structural requirements necessary for activity. Evaluation of selected steroids for activity against TBPS-induced convulsions show similar requirements for activity. Interestingly, steroids (e.g., 5 alpha-pregnan-3 alpha, 20 alpha-diol) were identified that have high potency but limited efficacy as modulators of (35S)TBPS binding. These characteristics are reminiscent of the clinically useful benzodiazepines (BZs) such as clonazepam. However, interactions between the prototypical anesthetic-barbiturate, sodium pentobarbital, and steroids active at the Cl- channel suggest that they do not share a common site of action as allosteric modulators of (35S)TBPS and BZ receptor binding. The most potent steroid evaluated, 5 alpha-pregnan-3 alpha-ol-20-one, modulates (35S)TBPS binding at low concentrations (IC50 approximately 17 nM) in a regionally dependent manner. All (35S)TBPS binding sites appear to be functionally coupled to a steroid modulatory site. Because several of the active steroids are metabolites of progesterone, their ability to inhibit the binding of (3H)promegestrone to the cytosolic progestin receptor in rat uterus was evaluated. Those steroids showing potent activity at the GABAA receptor-Cl- ionophore were inactive at the intracellular progestin receptor. Such specificity coupled with their high potency provide additional support for the hypothesis that some of these steroids may be involved in the homeostatic regulation of brain excitability via the GABAA-BZ receptor complex.

  15. Calcium sensing in exocytosis

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wu, Bingbing; Han, Weiping

    2012-01-01

    Neurotransmitters, neuropeptides and hormones are released through regulated exocytosis of synaptic vesicles and large dense core vesicles. This complex and highly regulated process is orchestrated by SNAREs and their associated proteins. The triggering signal for regulated exocytosis is usually...... an increase in intracellular calcium levels. Besides the triggering role, calcium signaling modulates the precise amount and kinetics of vesicle release. Thus, it is a central question to understand the molecular machineries responsible for calcium sensing in exocytosis. Here we provide an overview of our...

  16. Myoglobin-biomimetic electroactive materials made by surface molecular imprinting on silica beads and their use as ionophores in polymeric membranes for potentiometric transduction.

    Science.gov (United States)

    Moreira, Felismina T C; Dutra, Rosa A F; Noronha, Joao P C; Sales, M Goreti F

    2011-08-15

    Myoglobin (Mb) is among the cardiac biomarkers playing a major role in urgent diagnosis of cardiovascular diseases. Its monitoring in point-of-care is therefore fundamental. Pursuing this goal, a novel biomimetic ionophore for the potentiometric transduction of Mb is presented. It was synthesized by surface molecular imprinting (SMI) with the purpose of developing highly efficient sensor layers for near-stereochemical recognition of Mb. The template (Mb) was imprinted on a silane surface that was covalently attached to silica beads by means of self-assembled monolayers. First the silica was modified with an external layer of aldehyde groups. Then, Mb was attached by reaction with its amine groups (on the external surface) and subsequent formation of imine bonds. The vacant places surrounding Mb were filled by polymerization of the silane monomers 3-aminopropyltrimethoxysilane (APTMS) and propyltrimethoxysilane (PTMS). Finally, the template was removed by imine cleavage after treatment with oxalic acid. The results materials were finely dispersed in plasticized PVC selective membranes and used as ionophores in potentiometric transduction. The best analytical features were found in HEPES buffer of pH 4. Under this condition, the limits of detection were of 1.3 × 10(-6)mol/L for a linear response after 8.0 × 10(-7) mol/L with an anionic slope of -65.9 mV/decade. The imprinting effect was tested by preparing non-imprinted (NI) particles and employing these materials as ionophores. The resulting membranes showed no ability to detect Mb. Good selectivity was observed towards creatinine, sacarose, fructose, galactose, sodium glutamate, and alanine. The analytical application was conducted successfully and showed accurate and precise results. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Solvation properties of natural and synthetic ionophores. I. Stoichiometry of complexes with alkali and alkaline earth cations in aprotic organic solvents.

    Science.gov (United States)

    Olsher, U

    1982-01-01

    Ion-solvent interactions play a very important role in the studies of stoichiometry, structure, and stability of complexes of cations with natural and synthetic ionophores. These compounds are extremely useful in study of the interaction of neutral salts with macromolecules and the mechanism of cation transport across biological membranes. Knowledge of the ionophore solvation properties enables one to choose a suitable solvent for complexation studies and to obtain detailed information on the solvent effect. We would like to present in this paper a very simple method of estimating the solvation properties of ionophores. We treat the ligand as an assembly of individual noninteracting binding sites. The solvation properties of solvents can be used to represent the solvation sites in natural and synthetic ligands. The solvation properties are represented by the Gutmann donor number (DN) of the model solvent. We can define the solvation ability of a ligand binding site be "donor number of binding site" (DN binding site), which in turn can be represented by the DN of the appropriate model solvent. The average DN of the ligand (DN average) is defined as [xi ni-1 (DN binding site)i]/n, where n is the number of the ligand binding sites. Comparison of the DN average with the DN solvent, together with the knowledge of the composition of the system, characterizes remarkably well the solvation properties of the ligand. This model explains (a) the stoichiometry of many alkali and alkaline earth cation complexes with natural and synthetic ligands in aprotic organic solvents, (b) the transport of alkali and alkaline earth cations across lipid bilayers, and (c) how polypeptides and proteins interact with neutral salts in solutions. PMID:7139034

  18. Bone repair in calcium-deficient rats: comparison of xylitol+calcium carbonate with calcium carbonate, calcium lactate and calcium citrate on the repletion of calcium.

    Science.gov (United States)

    Hämäläinen, M M

    1994-06-01

    The potential value of xylitol in calcium therapy was evaluated by comparing the effect of dietary xylitol (50 g/kg diet) + calcium carbonate with the effects of calcium carbonate, calcium lactate and calcium citrate on bone repair of young male rats after the rats consumed for 3 wk a calcium-deficient diet (0.2 g Ca/kg diet). After this calcium-depletion period, the rats were fed for 2 wk one of four diets, each containing 5 g Ca/kg diet as one of the four dietary calcium sources. The diet of the control animals was supplemented with CaCO3 (5 g Ca/kg diet) throughout the study. The Ca-deficient rats showed low bone mass, low serum calcium and high serum 1,25-dihydroxycholecalciferol, parathyroid hormone (1-34 fraction) and osteocalcin concentrations. They also excreted magnesium, phosphate and hydroxyproline in the urine in high concentrations, and had high bone alkaline phosphatase and tartrate-resistant acid phosphatase activities. Most of these changes were reversed by the administered of the calcium salts. The highest recoveries of femoral dry weight, calcium, magnesium and phosphate were observed in the groups receiving xylitol+CaCO3 and calcium lactate. Calcium lactate and calcium citrate caused low serum phosphate concentration compared with rats receiving CaCO3 and with the age-matched Ca-replete controls. Xylitol-treated rats excreted more calcium and magnesium in urine than did the other rats, probably due to increased absorption of these minerals from the gut. These results suggest that dietary xylitol improves the bioavailability of calcium salts.

  19. Calcium – how and why?

    Indian Academy of Sciences (India)

    Unknown

    Calcium is among the most commonly used ions, in a multitude of biological functions, so much so that it is impossible to imagine life without calcium. In this article I have attempted to address the question as to how calcium has achieved this status with a brief mention of the history of calcium research in biology. It appears ...

  20. Application of the zona-free manipulation technique to porcine somatic nuclear transfer

    DEFF Research Database (Denmark)

    Booth, P J; Tan, S J; Holm, P

    2001-01-01

    The recent demonstration of a successful zona-free manipulation technique for bovine somatic nuclear transfer (NT) that is both simpler and less labor intensive is of considerable benefit to advance the applications of this technology. Here, we describe that this method is also applicable...... to porcine somatic NT. Porcine cumulus oocyte complexes were matured in TCM-199 medium before sequential removal of the cumulus and zonae. Zona-free oocytes were bisected using a microknife, and the halves containing the metaphase plate (as determined by Hoechst 33342 staining) were discarded. Each half...... activated in calcium ionophore A23187 followed by DMAP and were then individually cultured in microwells in NCSU-23 medium. On day 7 after activation, blastocyst yield and total cell numbers were counted. Of 279 attempted reconstructed NT embryos, 85.0 +/- 2.8% (mean +/- SEM; n = 5 replicates) successfully...

  1. Influence of recipient cytoplasm cell stage on transcription in bovine nucleus transfer embryos

    DEFF Research Database (Denmark)

    Smith, Steven D.; Soloy, Eva; Kanka, Jiri

    1996-01-01

    Nucleus transfer for the production of multiple embryos derived from a donor embryo relies upon the reprogramming of the donor nucleus so that it behaves similar to a zygotic nucleus. One indication of nucleus reprogramming is the RNA synthetic activity. In normal bovine embryogenesis, the embryo...... relies upon maternally derived RNA transcripts up to the 8-cell stage, at which time it begins to transcribe its own RNA. In this experiment, RNA synthesis was detected in nucleus transfer embryos (NTE) and control embryos by pulsing with 3H-uridine, fixation, and autoradiography on semithin sections....... NTE were produced using either a MII phase (nonactivated) cytoplasts at 32 hr of maturation or S-phase (activated) cytoplasts activated with calcium ionophore A23187 and cycloheximide treatment approximately 8 hr prior to fusion with a blastomere from an in-vitro-produced morula stage embryo at 32 hr...

  2. Retroviral-mediated gene transfer of the porcine choline acetyltransferase: a model to study the synthesis and secretion of acetylcholine in mammalian cells.

    Science.gov (United States)

    Xi, X G; Horellou, P; Leroy, C; Mallet, J

    1993-05-01

    We have constructed a recombinant retrovirus that expresses choline acetyltransferase (ChAT) by placing the porcine enzyme cDNA under the control of the 5' long terminal repeat of the retroviral vector pMMuLV. Using retrovirus-mediated gene transfer, we have expressed ChAT in astroglial (STR-SVLT) and neuroendocrine (RIN) cell lines. Both genetically modified cell types synthesize acetylcholine (ACh). ACh is also present in the culture medium at a low concentration relative to that found in the modified cells. This result suggests that the synthesized ACh is retained within the cells and released by these two cell types. Release of ACh is not increased in the presence of the calcium ionophore A23187 or by depolarizing concentrations of potassium in either STR-SVLT or in RIN cells. The implications of these studies for understanding ACh release mechanisms are discussed.

  3. Release of prostaglandin D2 by murine mast cells: importance of metabolite formation for antiproliferative activity

    Directory of Open Access Journals (Sweden)

    C. Haberl

    1998-01-01

    Full Text Available Prostaglandin (PG D2 , PGJ2 and Δ12 -PGJ2 are antiproliferative eicosanoids. We investigated the production of PGD2 by murine bone marrow-derived mast cells (BMMC taking into consideration metabolism of PGD2 to PGD2 and Δ12-PGJ2. PG-metabolites were quantified by high performance liquid chromatography (HPLC combined with radioimmunoassay (RIA. Stimulated with calcium ionophore A23187 BMMC released eight-fold more PGJ2 and Δ12-PGJ2 than PGD2. Conversion of endogenously produced PGD2 to PGJ2 and Δ12-PGJ2 proceeded rapidly in contrast to metabolism of exogenously added PGD2. The antiproliferative potency of these prostaglandins is demonstrated in vitro. We conclude that determination of PGD2 production by mast cells must take into consideration rapid conversion to active derivatives, which may play a significant role in growth regulation.

  4. Calcium and Your Child

    Science.gov (United States)

    ... Milk Allergy Figuring Out Food Labels What's a Vegetarian? Osteoporosis Minerals Your Bones Mineral Chart Vitamin D ... Need to Drink Milk? Lactose Intolerance Becoming a Vegetarian Soy Foods and Health Calcium Bones, Muscles, and ...

  5. Stoichiometry of Calcium Medicines

    Science.gov (United States)

    Pinto, Gabriel

    2005-01-01

    The topic of calcium supplement and its effects on human lives is presented in the way of questions to the students. It enables the students to realize the relevance of chemistry outside the classroom surrounding.

  6. Magnesium, calcium and cancer

    National Research Council Canada - National Science Library

    Anghileri, Leopoldo J

    2009-01-01

    Magnesium ion (Mg(2+)) and calcium ion (Ca(2+)) control a diverse and important range of cellular processes, such as gene transcription, cell proliferation, neoplastic transformation, immune response and therapeutic treatment...

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  8. 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

  9. [Microbial geochemical calcium cycle].

    Science.gov (United States)

    Zavarzin, G A

    2002-01-01

    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  10. Ionophore-Based Potentiometric Sensors for the Flow-Injection Determination of Promethazine Hydrochloride in Pharmaceutical Formulations and Human Urine

    Directory of Open Access Journals (Sweden)

    Suad Mustafa Al-Araji

    2011-01-01

    Full Text Available Plasticised poly(vinyl chloride-based membranes containing the ionophores (α-, β- and γ-cyclodextrins (CD, dibenzo-18-crown-6 (DB18C6 and dibenzo-30-crown-10 (DB30C10 were evaluated for their potentiometric response towards promethazine (PM in a flow injection analysis (FIA set-up. Good responses were obtained when β- and γ-CDs, and DB30C10 were used. The performance characteristics were further improved when tetrakis(4-chlorophenyl borate (KTPB was added to the membrane. The sensor based on β-CD, bis(2-ethylhexyl adipate (BEHA and KTPB exhibited the best performance among the eighteen sensor compositions that were tested. The response was linear from 1 x 10−5 to 1 x 10−2 M, slope was 61.3 mV decade−1, the pH independent region ranged from 4.5 to 7.0, a limit of detection of 5.3 x 10−6 M was possible and a lifetime of more than a month was observed when used in the FIA system. Other plasticisers such as dioctyl phenylphosphonate and tributyl phosphate do not show significant improvements in the quality of the sensors. The promising sensors were further tested for the effects of foreign ions (Li+, Na+, K+, Mg2+, Ca2+, Co2+, Cu2+, Cr3+, Fe3+, glucose, fructose. FIA conditions (e.g., effects of flow rate, injection volume, pH of the carrier stream were also studied when the best sensor was used (based on β-CD. The sensor was applied to the determination of PM in four pharmaceutical preparations and human urine that were spiked with different levels of PM. Good agreement between the sensor and the manufacturer’s claimed values (for pharmaceutical preparations was obtained, while mean recoveries of 98.6% were obtained for spiked urine samples. The molecular recognition features of the sensors as revealed by molecular modelling were rationalised by the nature of the interactions and complexation energies between the host and guest molecules.

  11. Ionophore-Based Potentiometric Sensors for the Flow-Injection Determination of Promethazine Hydrochloride in Pharmaceutical Formulations and Human Urine

    Science.gov (United States)

    Hassan, Ahmed Khudhair; Saad, Bahruddin; Ghani, Sulaiman Ab; Adnan, Rohana; Rahim, Afidah Abdul; Ahmad, Norariza; Mokhtar, Marina; Ameen, Suham Tawfiq; Al-Araji, Suad Mustafa

    2011-01-01

    Plasticised poly(vinyl chloride)-based membranes containing the ionophores (α-, β- and γ-cyclodextrins (CD), dibenzo-18-crown-6 (DB18C6) and dibenzo-30-crown-10 (DB30C10) were evaluated for their potentiometric response towards promethazine (PM) in a flow injection analysis (FIA) set-up. Good responses were obtained when β- and γ-CDs, and DB30C10 were used. The performance characteristics were further improved when tetrakis(4-chlorophenyl) borate (KTPB) was added to the membrane. The sensor based on β-CD, bis(2-ethylhexyl) adipate (BEHA) and KTPB exhibited the best performance among the eighteen sensor compositions that were tested. The response was linear from 1 × 10−5 to 1 × 10−2 M, slope was 61.3 mV decade−1, the pH independent region ranged from 4.5 to 7.0, a limit of detection of 5.3 × 10−6 M was possible and a lifetime of more than a month was observed when used in the FIA system. Other plasticisers such as dioctyl phenylphosphonate and tributyl phosphate do not show significant improvements in the quality of the sensors. The promising sensors were further tested for the effects of foreign ions (Li+, Na+, K+, Mg2+, Ca2+, Co2+, Cu2+, Cr3+, Fe3+, glucose, fructose). FIA conditions (e.g., effects of flow rate, injection volume, pH of the carrier stream) were also studied when the best sensor was used (based on β-CD). The sensor was applied to the determination of PM in four pharmaceutical preparations and human urine that were spiked with different levels of PM. Good agreement between the sensor and the manufacturer’s claimed values (for pharmaceutical preparations) was obtained, while mean recoveries of 98.6% were obtained for spiked urine samples. The molecular recognition features of the sensors as revealed by molecular modelling were rationalised by the nature of the interactions and complexation energies between the host and guest molecules. PMID:22346617

  12. Validation of a liquid chromatography-electrospray ionization tandem mass spectrometric method to determine six polyether ionophores in raw, UHT, pasteurized and powdered milk.

    Science.gov (United States)

    Pereira, Mararlene Ulberg; Spisso, Bernardete Ferraz; Jacob, Silvana do Couto; Monteiro, Mychelle Alves; Ferreira, Rosana Gomes; Carlos, Betânia de Souza; da Nóbrega, Armi Wanderley

    2016-04-01

    This study aimed to validate a method developed for the determination of six antibiotics from the polyether ionophore class (lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin) at residue levels in raw, UHT, pasteurized and powdered milk using QuEChERS extraction and high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The validation was conducted under an in-house laboratory protocol that is primarily based on 2002/657/EC Decision, but takes in account the variability of matrix sources. Overall recoveries between 93% and 113% with relative standard deviations up to 16% were obtained under intermediate precision conditions. CCα calculated values did not exceed 20% the Maximum Residue Limit for monensin and 25% the Maximum Levels for all other substances. The method showed to be simple, fast and suitable for verifying the compliance of raw and processed milk samples regarding the limits recommended by Codex Alimentarius and those adopted in European Community for polyether ionophores. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Calcium orthophosphates in dentistry.

    Science.gov (United States)

    Dorozhkin, Sergey V

    2013-06-01

    Dental caries, also known as tooth decay or a cavity, remains a major public health problem in the most communities even though the prevalence of disease has decreased since the introduction of fluorides for dental care. Therefore, biomaterials to fill dental defects appear to be necessary to fulfill customers' needs regarding the properties and the processing of the products. Bioceramics and glass-ceramics are widely used for these purposes, as dental inlays, onlays, veneers, crowns or bridges. Calcium orthophosphates belong to bioceramics but they have some specific advantages over other types of bioceramics due to a chemical similarity to the inorganic part of both human and mammalian bones and teeth. Therefore, calcium orthophosphates (both alone and as components of various formulations) are used in dentistry as both dental fillers and implantable scaffolds. This review provides brief information on calcium orthophosphates and describes in details current state-of-the-art on their applications in dentistry and dentistry-related fields. Among the recognized dental specialties, calcium orthophosphates are most frequently used in periodontics; however, the majority of the publications on calcium orthophosphates in dentistry are devoted to unspecified "dental" fields.

  14. [A control study of artificial oocyte activation in the same period].

    Science.gov (United States)

    Hao, D Y; Zhang, R; Zhang, X; Shen, C Y; Yang, Y; Wu, W B; Liu, Y L; Liu, J; Zhang, J R; Wang, X L

    2016-11-22

    Objective: To compare the fertility rate and embryo outcome between normal fertilization and the use of Calcium ionophore A23187 on the same period of the same cycle of human ovum for artificial activation. Methods: Patients who conducted the intracytoplasmic sperm injection (ICSI) cycle in vitro fertilization assisted reproductive from January 2015 to December in reproductive center of the Third Affiliated Hospital of Zhengzhou University were enrolled.The protocol of this study was approved by the ethics committee of The Third Affiliated Hospital of Zhengzhou University.The subjects must met at least one of the inclusion criteria: (1)the normal fertilization rate was less than 30% ICSI in the previous ICSI cycle; (2)no good quality embryos in a previous period of third days in ICSI; (3)patients with globozoospermia.The ovum were randomly divided into two groups, control group and artificial oocyte activation (AOA) group. In the control group, the eggs were treated with routine ICSI operation, and the AOA group was activated by A23187 after ICSI. Normal fertilization rate, cleavage rate, pregnancy and birth outcome of two groups were compared. Results: The 2PN fertilization rate in the AOA group 65.93% (60/91) was significantly higher than that in the control group 46.67% (41/89) (Pfertilization rate was significantly higher (Pfertilization rate was significantly higher (Pfertilization rate of ICSI. But the effects of early embryonic development and the safety of generation need to be further studied.

  15. Mitochondrial respiration is sensitive to cytoarchitectural breakdown.

    Science.gov (United States)

    Kandel, Judith; Angelin, Alessia A; Wallace, Douglas C; Eckmann, David M

    2016-11-07

    An abundance of research suggests that cellular mitochondrial and cytoskeletal disruption are related, but few studies have directly investigated causative connections between the two. We previously demonstrated that inhibiting microtubule and microfilament polymerization affects mitochondrial motility on the whole-cell level in fibroblasts. Since mitochondrial motility can be indicative of mitochondrial function, we now further characterize the effects of these cytoskeletal inhibitors on mitochondrial potential, morphology and respiration. We found that although they did not reduce mitochondrial inner membrane potential, cytoskeletal toxins induced significant decreases in basal mitochondrial respiration. In some cases, basal respiration was only affected after cells were pretreated with the calcium ionophore A23187 in order to stress mitochondrial function. In most cases, mitochondrial morphology remained unaffected, but extreme microfilament depolymerization or combined intermediate doses of microtubule and microfilament toxins resulted in decreased mitochondrial lengths. Interestingly, these two particular exposures did not affect mitochondrial respiration in cells not sensitized with A23187, indicating an interplay between mitochondrial morphology and respiration. In all cases, inducing maximal respiration diminished differences between control and experimental groups, suggesting that reduced basal respiration originates as a largely elective rather than pathological symptom of cytoskeletal impairment. However, viability experiments suggest that even this type of respiration decrease may be associated with cell death.

  16. Calcium Signalling: Fishing Out Molecules of Mitochondrial Calcium Transport

    OpenAIRE

    Hajnóczky, György; Csordás, György

    2010-01-01

    Cellular energy metabolism, survival and death are controlled by mitochondrial calcium signals originating in the cytoplasm. Now, RNAi studies link three proteins — MICU1, NCLX and LETM1 — to the previously unknown molecular mechanism of mitochondrial calcium transport.

  17. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    Science.gov (United States)

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

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

  18. Co-incubation of PMN and CaCo-2 cells modulates inflammatory potential.

    Science.gov (United States)

    Schaefer, M B; Schaefer, C A; Hecker, M; Morty, R E; Witzenrath, M; Seeger, W; Mayer, K

    2017-05-20

    Polymorphonuclear granulocytes (PMN) are activated in inflammatory reactions. Intestinal epithelial cells are relevant for maintaining the intestinal barrier. We examined interactions of PMN and intestinal epithelial cell-like CaCo-2 cells to elucidate their regulation of inflammatory signalling and the impact of cyclooxygenase (COX), nitric oxide (NO) and platelet-activating factor (PAF). Human PMN and CaCo-2 cells, separately and in co-incubation, were stimulated with the calcium ionophore A23187 or with N-Formyl-methionyl-leucyl-phenylalanin (fMLP) that activates PMN only. Human neutrophil elastase (HNE) and respiratory Burst were measured. To evaluate the modulation of inflammatory crosstalk we applied inhibitors of COX (acetyl salicylic acid; ASA), NO-synthase (N-monomethyl-L-arginin; L-NMMA), and the PAF-receptor (WEB2086). Unstimulated, co-incubation of CaCo-2 cells and PMN led to significantly reduced Burst and elevated HNE as compared to PMN. After stimulation with A23187, co-incubation resulted in an inhibition of Burst and HNE. Using fMLP co-incubation failed to modulate Burst but increased HNE. Without stimulation, all three inhibitors abolished the effect of co-incubation on Burst but did not change HNE.  ASA partly prevented modulation of Burst L-NMMA and WEB2086 did not change Burst but abolished mitigation of HNE. Without stimulation, co-incubation reduced Burst and elevated HNE. Activation of PMN and CaCo-2 cells by fMLP as compared to A23187 resulted in a completely different pattern of Burst and HNE, possibly due to single vs. dual cell activation. Anti-inflammatory effect of co-incubation might in part be due to due to COX-signalling governing Burst whereas NO- and PAF-dependent signalling seemed to control HNE release.

  19. Children's Bone Health and Calcium

    Science.gov (United States)

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

  20. Stable prenucleation calcium carbonate clusters

    OpenAIRE

    Gebauer, Denis; Völkel, Antje; Cölfen, Helmut

    2008-01-01

    Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters. We demonstrate that dissolved calcium carbonate...

  1. Assay for calcium channels

    Energy Technology Data Exchange (ETDEWEB)

    Glossmann, H.; Ferry, D.R.

    1985-01-01

    This chapter focuses on biochemical assays for Ca/sup 2 +/-selective channels in electrically excitable membranes which are blocked in electrophysiological and pharmacological experiments by verapamil, 1,4-dihydropyridines, diltiazen (and various other drugs), as well as inorganic di- or trivalent cations. The strategy employed is to use radiolabeled 1,4-dihydropyridine derivatives which block calcium channels with ED/sub 50/ values in the nanomolar range. Although tritiated d-cis-diltiazem and verapamil can be used to label calcium channels, the 1,4-dihydropyridines offer numerous advantages. The various sections cover tissue specificity of channel labeling, the complex interactions of divalent cations with the (/sup 3/H)nimodipine-labeled calcium channels, and the allosteric regulation of (/sup 3/H)nimodipine binding by the optically pure enantiomers of phenylalkylamine and benzothiazepine calcium channel blockers. A comparison of the properties of different tritiated 1,4-dihydropyridine radioligands and the iodinated channel probe (/sup 125/I)iodipine is given.

  2. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about 500...

  3. Artificial oocyte activation in intracytoplasmic sperm injection cycles using testicular sperm in human in vitro fertilization.

    Science.gov (United States)

    Kang, Hee Jung; Lee, Sun-Hee; Park, Yong-Seog; Lim, Chun Kyu; Ko, Duck Sung; Yang, Kwang Moon; Park, Dong-Wook

    2015-06-01

    Artificial oocyte activation (AOA) is an effective method to avoid total fertilization failure in human in vitro fertilization-embryo transfer (IVF-ET) cycles. AOA performed using a calcium ionophore can induce calcium oscillation in oocytes and initiate the fertilization process. We evaluated the usefulness of AOA with a calcium ionophore in cases of total fertilization failure in previous cycles and in cases of severe male factor infertility patients with non-motile spermatozoa after pentoxifylline (PF) treatment. The present study describes 29 intracytoplasmic sperm injection (ICSI)-AOA cycles involving male factor infertility at Cheil General Hospital from January 2006 to June 2013. Patients were divided into two groups (control, n=480; AOA, n=29) depending on whether or not AOA using a calcium ionophore (A23187) was performed after testicular sperm extraction-ICSI (TESE-ICSI). The AOA group was further split into subgroups according to sperm motility after PF treatment: i.e., motile sperm-injected (n=12) and non-motile sperm-injected (n=17) groups (total n=29 cycles). The good embryo rate (52.3% vs. 66.9%), pregnancy rate (20.7% vs. 52.1%), and delivery rate (10.3% vs. 40.8%) were lower in the PF/AOA group than in the control group. When evaluating the effects of restoration of sperm motility after PF treatment on clinical outcomes there was no difference in fertilization rate (66.6% vs. 64.7% in non-motile and motile sperm, respectively), pregnancy rate (17.6% vs. 33.3%), or delivery rate (5.9% vs. 16.7%) between the two groups. We suggest that oocyte activation is a useful method to ensure fertilization in TESE-ICSI cycles regardless of restoration of sperm motility after PF treatment. AOA may be useful in selected patients who have a low fertilization rate or total fertilization failure.

  4. The Plasma Membrane Calcium Pump

    Science.gov (United States)

    Rasmussen, H.

    1983-01-01

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

  5. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

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

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...

  6. Impregnating Coal With Calcium Carbonate

    Science.gov (United States)

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

    1991-01-01

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

  7. Integration of Kinase and Calcium Signaling at the Level of Chromatin Underlies Inducible Gene Activation in T Cells.

    Science.gov (United States)

    Brignall, Ruth; Cauchy, Pierre; Bevington, Sarah L; Gorman, Bethany; Pisco, Angela O; Bagnall, James; Boddington, Christopher; Rowe, William; England, Hazel; Rich, Kevin; Schmidt, Lorraine; Dyer, Nigel P; Travis, Mark A; Ott, Sascha; Jackson, Dean A; Cockerill, Peter N; Paszek, Pawel

    2017-10-15

    TCR signaling pathways cooperate to activate the inducible transcription factors NF-κB, NFAT, and AP-1. In this study, using the calcium ionophore ionomycin and/or PMA on Jurkat T cells, we show that the gene expression program associated with activation of TCR signaling is closely related to specific chromatin landscapes. We find that calcium and kinase signaling cooperate to induce chromatin remodeling at ∼2100 chromatin regions, which demonstrate enriched binding motifs for inducible factors and correlate with target gene expression. We found that these regions typically function as inducible enhancers. Many of these elements contain composite NFAT/AP-1 sites, which typically support cooperative binding, thus further reinforcing the need for cooperation between calcium and kinase signaling in the activation of genes in T cells. In contrast, treatment with PMA or ionomycin alone induces chromatin remodeling at far fewer regions (∼600 and ∼350, respectively), which mostly represent a subset of those induced by costimulation. This suggests that the integration of TCR signaling largely occurs at the level of chromatin, which we propose plays a crucial role in regulating T cell activation. Copyright © 2017 The Authors.

  8. Involvement of second messengers in the signaling pathway of vitellogenesis-inhibiting hormone and their effects on vitellogenin mRNA expression in the whiteleg shrimp, Litopenaeus vannamei.

    Science.gov (United States)

    Bae, Sun-Hye; Okutsu, Tomoyuki; Tsutsui, Naoaki; Kang, Bong Jung; Chen, Hsiang-Yin; Wilder, Marcy N

    2017-05-15

    We incubated fragments of Litopenaeus vannamei ovary to investigate second messengers involved in the regulation of vitellogenin (vg) mRNA levels. The use of 100nM recombinant vitellogenesis-inhibiting hormone (VIH) (corresponding to recombinant L. vannamei sinus gland peptide-G: rLiv-SGP-G) significantly reduced vg mRNA expression in sub-adults after 8h incubation to less than 20% of the control. The concentration of intracellular cyclic guanosine monophosphate (cGMP) increased 3.2-fold relative to the control after 2h incubation with rLiv-SGP-G. However, it reached levels 18-fold relative to the control after 0.5h incubation with rLiv-SGP-G where 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor) was also added. Moreover, vg mRNA expression was significantly reduced to less than 50% of the control after 24h incubation with 1μM A23187 (a calcium ionophore). Thus, rLiv-SGP-G and calcium ionophore reduced vg mRNA expression in in vitro-cultured ovary, and cGMP may be involved in the signaling pathway of VIH. Overall, the above results suggest that vg mRNA expression might be inhibited in vitro by increasing intracellular cGMP and Ca2+ in L. vannamei ovary. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Effects of Echium plantagineum L. Bee Pollen on Basophil Degranulation: Relationship with Metabolic Profile

    Directory of Open Access Journals (Sweden)

    Eduarda Moita

    2014-07-01

    Full Text Available This study aimed to evaluate the anti-allergic potential of Echium plantagineum L. bee pollen and to characterize its primary metabolites. The activity of E. plantagineum hydromethanolic extract, devoid of alkaloids, was tested against β-hexosaminidase release in rat basophilic leukemic cells (RBL-2H3. Two different stimuli were used: calcium ionophore A23187 and IgE/antigen. Lipoxygenase inhibitory activity was evaluated in a cell-free system using soybean lipoxygenase. Additionally, the extract was analysed by HPLC-UV for organic acids and by GC-IT/MS for fatty acids. In RBL-2H3 cells stimulated either with calcium ionophore or IgE/antigen, the hydromethanolic extract significantly decreased β-hexosaminidase release until the concentration of 2.08 mg/mL, without compromising cellular viability. No effect was found on lipoxygenase. Concerning extract composition, eight organic acids and five fatty acids were determined for the first time. Malonic acid (80% and α-linolenic acid (27% were the main compounds in each class. Overall, this study shows promising results, substantiating for the first time the utility of intake of E. plantagineum bee pollen to prevent allergy and ameliorate allergy symptoms, although a potentiation of an allergic response can occur, depending on the dose used.

  10. Cyclosporin A does not protect the disruption of the inner mitochondrial membrane potential induced by potassium ionophores in intact K562 cells.

    Science.gov (United States)

    Marques-Santos, Luis F; Coqueiro, Vivian M; Rumjanek, Vivian M

    2006-03-01

    Mitochondrial dysfunction has been widely associated with programmed cell death. Studies of intact cells are important for the understanding of the process of cell death and its relation to mitochondrial physiology. Using cytofluorometric approaches we studied the mitochondrial behavior in an erythroleukemic cell line. The effects of protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP), potassium exchanger (nigericin), potassium ionophore (valinomycin), Na+K+-ATPase inhibitor (ouabain) and mitochondrial permeability transition pore inhibitor (cyclosporin A) were evaluated. Cyclosporin A (CSA) was very effective in attenuating the disruption of inner mitochondrial membrane potential induced by CCCP. However, CSA failed to protect the loss of inner mitochondrial membrane potential induced by potassium intracellular flux manipulation. Our findings suggest that mitochondrial cyclophilin is not involved in the cell events mediated by deregulation of potassium flux, underlining the need for further studies in intact tumor cells for a better understanding of the involvement of mitochondria physiology in cell death events.

  11. Evidence for an extracellular zinc-veneer in rodent brains from experiments with Zn-ionophores and ZnT3 knockouts.

    Science.gov (United States)

    Nydegger, Irma; Rumschik, Sean M; Zhao, Jinfu; Kay, Alan R

    2012-10-17

    Ionic zinc is found at a high concentration in some glutamatergic vesicles of the mammalian brain. Ionic zinc is also found chelated to macromolecules in the extracellular space, constituting what has been called the "zinc veneer". In this communication we show that the zinc ionophore, pyrithione, can be used to demonstrate the presence of the veneer. Application of pyrithione without added ionic zinc to rodent hippocampal slices mobilizes extracellular zinc, which can be detected intracellularly by the zinc probe FluoZin-3. In addition, we show that ZnT3 null mice, which lack the transporter responsible for stocking synaptic vesicles, nevertheless do have a zinc veneer, albeit diminished compared to wild type animals. The presence of the zinc veneer in ZnT3 null mice may account for the absence of any marked deficit in these animals.

  12. Polymeric optical sensors for selective and sensitive nitrite detection using cobalt(III) corrole and rhodium(III) porphyrin as ionophores.

    Science.gov (United States)

    Yang, Si; Wo, Yaqi; Meyerhoff, Mark E

    2014-09-16

    Cobalt(III) 5,10,15-tris(4-tert-butylphenyl) corrole with a triphenylphosphine axial ligand and rhodium(III) 5,10,15,20-tetra(p-tert-butylphenyl) porphyrin are incorporated into plasticized poly(vinyl chloride) films to fabricate nitrite-selective bulk optodes via absorbance measurements. The resulting films yield sensitive, fast and fully reversible response toward nitrite with significantly enhanced nitrite selectivity over other anions including lipophilic anions such as thiocyanate and perchlorate. The selectivity patterns differ greatly from the Hofmeister series based on anion lipophilicity and are consistent with selectivity obtained with potentiometric sensors based on the same ionophores. The optical nitrite sensors are shown to be useful for detecting rates of emission of nitric oxide (NO) from NO releasing polymers containing S-nitroso-N-acetyl-DL-penicillamine. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Polymeric Optical Sensors for Selective and Sensitive Nitrite Detection Using Cobalt(III) Corrole and Rh(III) Porphyrin as Ionophores

    Science.gov (United States)

    Yang, Si; Wo, Yaqi; Meyerhoff, Mark E.

    2014-01-01

    Cobalt(III) 5, 10, 15-tris(4-tert-butylphenyl) corrole with a triphenylphosphine axial ligand and rhodium(III) 5,10,15,20-tetra(p-tert-butylphenyl)porphyrin are incorporated into plasticized poly(vinyl chloride) films to fabricate nitrite-selective bulk optodes via absorbance measurements. The resulting films yield sensitive, fast and fully reversible response toward nitrite with significantly enhanced nitrite selectivity over other anions including lipophilic anions such as thiocyanate and perchlorate. The selectivity patterns differ greatly from the Hofmeister series based on anion lipophilicity and are consistent with selectivity obtained with potentiometric sensors based on the same ionophores. The optical nitrite sensors are shown to be useful for detecting rates of emission of nitric oxide (NO) from NO releasing polymers containing S-nitroso-N-acetyl-penicillamine. PMID:25150700

  14. Calcium signaling in taste cells.

    Science.gov (United States)

    Medler, Kathryn F

    2015-09-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. This article is part of a Special Issue entitled: 13th European Symposium on Calcium. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Fabrication of new carbon paste electrodes based on gold nano-particles self-assembled to mercapto compounds as suitable ionophores for potentiometric determination of copper ions

    Directory of Open Access Journals (Sweden)

    Rasoul Pourtaghavi Talemi

    2013-12-01

    Full Text Available In the present study, we investigate the potentiometric behavior of Cu2+ carbon paste electrodes based on two mercapto compounds 2-ethylmino-5-mercapto-1,3,4-thiadiazole (EAMT and 2-acetylamino-5-mercapto-1,3,4-thiadiazole (AAMT self-assembled on gold nano-paricle (GNP as ionophore. Then, the obtained results from the modified electrodes are compared. The self-assembled ionophores exhibit a high selectivity for copper ion (Cu2+, in which the sulfur and nitrogen atoms in their structure play a significant role as the effective coordination donor site for the copper ion. Among these electrodes, the best performance was obtained with the sensor with a EAMT/graphite powder/paraffin oil weight ratio of 4.0/68/28 with 200 µL of GNP which exhibits the working concentration range of 1.6×10−9 to 6.3×10−2 M and a nernstian slope of 28.9±0.4 mVdecade−1 of copper(II activity. The detection limit of electrode was 2.9(±0.2×10−10M and potential response was pH ; in other words, it was independent across the range of 2.8–6.3. The proposed electrode presented very good selectivity and sensitivity towards the Cu2+ ions over a wide variety of cations including alkali, alkaline earth, transition and heavy metal ions. Moreover, the proposed electrode was successfully applied as an indicator electrode in the potentiometric titration of Cu(II ions with EDTA and also the potentiometric determination of copper ions in spiked water samples.

  16. The Novel SCN''- Ion-selective Electrode Based on the 1-Benzyl-3-(4-nitrophenyl) thio-urea Ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Mi; Kang, Dong Hyeon; Choe, Ju Eun; You, Jung Min; Go, Min Jeong; Lee, Jung Seong; Jeon, Seung Won [Chungnam National University, Daejeon (Korea, Republic of)

    2014-09-15

    A potentiometric sensor based on the 1-benzyl-3-(4-nitrophenyl) thio-urea was synthesized and tested as an ionophore in PVC based membrane sensor towards SCN - ions. This membrane exhibits a linear stable response over a wide concentration range (1.0 × 10''-5 to 1.0 × 10''-2 M) with a slope of -59.2 mV/dec., a detection limit of log[SCN''- ] = -5.05, and a selectivity coefficient for thiocyanate against perchlorate anion of logK{sub s}cn''pot = -0.133. The selectivity series of the membrane is as follows: SCN''- > ClO{sub 4}''- > I''- >NO{sub 3}''- >HSO{sub 3}''- > Cl''-HSO{sub '}'-''4 > F''- > CH{sub 3}COO''- > HCO''-''3 > Br''- > H{sub 2}PO{sub 4}''- > SO{sub 3}''-''2 > SO{sub 4}''-''2 > CO{sub 3}''-''2. The proposed electrode showed good selectivity and a good response for the SCN''- ion over a wide variety of other anions in pH 6.0 buffer solutions and has a fast response time of about < 5s.. The influences of the membrane by pH, ionophore, and plasticizer were studied.

  17. Simultaneous determination of polyether ionophores, macrolides and lincosamides in hen eggs by liquid chromatography-electrospray ionization tandem mass spectrometry using a simple solvent extraction.

    Science.gov (United States)

    Spisso, Bernardete Ferraz; Ferreira, Rosana Gomes; Pereira, Mararlene Ulberg; Monteiro, Mychelle Alves; Cruz, Tatiana Ávila; da Costa, Rafaela Pinto; Lima, Adélia Mara Belém; da Nóbrega, Armi Wanderley

    2010-12-03

    A liquid chromatography-electrospray ionization tandem mass spectrometric (LC-ESI-MS/MS) method was developed and validated for the determination of residues of 6 polyether ionophores (lasalocid, maduramicin, monensin, narasin, salinomycin, semduramicin), 3 macrolides (erythromycin, tylosin, clarithromycin) and 1 lincosamide (lincomycin) in eggs. Nigericin was used as qualitative internal standard. Samples were deproteinizated/extracted with acetonitrile without pH adjustments. Aliquots of the extracts were evaporated and reconstituted for injection in the instrument operated in positive multiple reaction monitoring (MRM) mode. The stability of the antibiotics and the intensity of the formed ions were considered in order to select a suitable solvent for the reconstitution of the obtained dry extracts. No clean-up steps were required and matrix effects were controlled by sample dilution, selection of appropriate chromatographic conditions and reduced injection volume. Good within-laboratory reproducibility was obtained, with relative standard deviations (RSD(R)) from 4.0 (semduramicin at 5 μgkg(-1)) to 18.6 (erythromycin at 25 μgkg(-1)) for the ionophores and macrolides. Lincomycin showed the least precise results, with a maximum RSD(R) of 20.2% at 75 μgkg(-1)). Satisfactory decision limits (CCα) and detection capabilities (CCβ) were also attained. Method limits of detection (LODs) from 0.04 (salinomycin) to 1.6 μgkg(-1) (lincomycin) were achieved. Method limits of quantification (LOQs) were from 0.14 to 5.3 μgkg(-1) for the same drugs, respectively. All the LOQs, except that obtained for maduramicin were remarkably below the lowest validation level. The proposed method is suitable for routine application in commercial egg samples. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

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

  19. Calcium metabolism and cardiovascular function after spaceflight

    Science.gov (United States)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; hide

    2002-01-01

    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P platelet free calcium (intracellular calcium concentration) were also reduced (P metabolism (P metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  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. Roles of calcium/calmodulin-dependent kinase II in long-term memory formation in crickets.

    Directory of Open Access Journals (Sweden)

    Makoto Mizunami

    Full Text Available Ca(2+/calmodulin (CaM-dependent protein kinase II (CaMKII is a key molecule in many systems of learning and memory in vertebrates, but roles of CaMKII in invertebrates have not been characterized in detail. We have suggested that serial activation of NO/cGMP signaling, cyclic nucleotide-gated channel, Ca(2+/CaM and cAMP signaling participates in long-term memory (LTM formation in olfactory conditioning in crickets, and here we show participation of CaMKII in LTM formation and propose its site of action in the biochemical cascades. Crickets subjected to 3-trial conditioning to associate an odor with reward exhibited memory that lasts for a few days, which is characterized as protein synthesis-dependent LTM. In contrast, animals subjected to 1-trial conditioning exhibited memory that lasts for only several hours (mid-term memory, MTM. Injection of a CaMKII inhibitor prior to 3-trial conditioning impaired 1-day memory retention but not 1-hour memory retention, suggesting that CaMKII participates in LTM formation but not in MTM formation. Animals injected with a cGMP analogue, calcium ionophore or cAMP analogue prior to 1-trial conditioning exhibited 1-day retention, and co-injection of a CaMKII inhibitor impaired induction of LTM by the cGMP analogue or that by the calcium ionophore but not that by the cAMP analogue, suggesting that CaMKII is downstream of cGMP production and Ca(2+ influx and upstream of cAMP production in biochemical cascades for LTM formation. Animals injected with an adenylyl cyclase (AC activator prior to 1-trial conditioning exhibited 1-day retention. Interestingly, a CaMKII inhibitor impaired LTM induction by the AC activator, although AC is expected to be a downstream target of CaMKII. The results suggest that CaMKII interacts with AC to facilitate cAMP production for LTM formation. We propose that CaMKII serves as a key molecule for interplay between Ca(2+ signaling and cAMP signaling for LTM formation, a new role of Ca

  2. Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia.

    Science.gov (United States)

    Wilson, Rosamund J; Copley, J Brian

    2017-01-01

    Calcium-based and non-calcium-based phosphate binders have similar efficacy in the treatment of hyperphosphatemia; however, calcium-based binders may be associated with hypercalcemia, vascular calcification, and adynamic bone disease. A post hoc analysis was carried out of data from a 16-week, Phase IV study of patients with end-stage renal disease (ESRD) who switched to lanthanum carbonate monotherapy from baseline calcium acetate/calcium carbonate monotherapy. Of the intent-to-treat population (N=2520), 752 patients with recorded dose data for calcium acetate (n=551)/calcium carbonate (n=201) at baseline and lanthanum carbonate at week 16 were studied. Elemental calcium intake, serum phosphate, corrected serum calcium, and serum intact parathyroid hormone levels were analyzed. Of the 551 patients with calcium acetate dose data, 271 (49.2%) had an elemental calcium intake of at least 1.5 g/day at baseline, and 142 (25.8%) had an intake of at least 2.0 g/day. Mean (95% confidence interval [CI]) serum phosphate levels were 6.1 (5.89, 6.21) mg/dL at baseline and 6.2 (6.04, 6.38) mg/dL at 16 weeks; mean (95% CI) corrected serum calcium levels were 9.3 (9.16, 9.44) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Of the 201 patients with calcium carbonate dose data, 117 (58.2%) had an elemental calcium intake of at least 1.5 g/day, and 76 (37.8%) had an intake of at least 2.0 g/day. Mean (95% CI) serum phosphate levels were 5.8 (5.52, 6.06) mg/dL at baseline and 5.8 (5.53, 6.05) mg/dL at week 16; mean (95% CI) corrected serum calcium levels were 9.7 (9.15, 10.25) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Calcium acetate/calcium carbonate phosphate binders, taken to control serum phosphate levels, may result in high levels of elemental calcium intake. This may lead to complications related to calcium balance.

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

    OpenAIRE

    Bizzozero, Julien; Scrivener, Karen

    2015-01-01

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

  4. Mixed calcium-magnesium pre-nucleation clusters enrich calcium

    OpenAIRE

    Verch, Andreas; Antonietti, Markus; Cölfen, Helmut

    2012-01-01

    It is demonstrated that magnesium and carbonate ions can form pre-nucleation clusters in analogy to calcium carbonate. If a mixed calcium and magnesium solution is brought in contact with carbonate ions, mixed pre-nucleation clusters form. The equilibrium constants for their formation are reported revealing that over the entire range of possible cation mixing ratios, calcium gets enriched over magnesium in the pre-nucleation clusters. This can explain high magnesium contents in amorphous calc...

  5. Biological Reactions to Calcium Phosphate-coated Calcium Carbonate Particles

    National Research Council Canada - National Science Library

    Tetsunari NISHIKAWA; Kazuya MASUNO; Tomoharu OKAMURA; Kazuya TOMINAGA; Masahiro WATO; Mayu KOKUBU; Koichi IMAI; Shoji TAKEDA; Yoichro TAGUCHI; Masatoshi UEDA; Akio TANAKA

    2010-01-01

    [SYNOPSIS][Objectives]: In order to histopathologically investigate biological reactions to materials used for scaffolds, we examined the cytotoxicity to calcium particles in vitro and bioabsorption in vivo...

  6. Osteoporosis, calcium and physical activity.

    OpenAIRE

    Martin, A. D.; Houston, C S

    1987-01-01

    Sales of calcium supplements have increased dramatically since 1983, as middle-aged women seek to prevent or treat bone loss due to osteoporosis. However, epidemiologic studies have failed to support the hypothesis that larger amounts of calcium are associated with increased bone density or a decreased incidence of fractures. The authors examine the evidence from controlled trials on the effects of calcium supplementation and physical activity on bone loss and find that weight-bearing activit...

  7. 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.

  8. Laser Sintered Calcium Phosphate Bone

    National Research Council Canada - National Science Library

    Vail, Neil

    1999-01-01

    ...) technology selective laser sintering (SLS). BME has successfully implemented a pilot facility to fabricate calcium phosphate implants using anatomical data coupled with the selective laser sintering process...

  9. Regulatory Action of Calcium Ion on Cyclic AMP-Enhanced Expression of Implantation-Related Factors in Human Endometrial Cells.

    Directory of Open Access Journals (Sweden)

    Kazuya Kusama

    Full Text Available Decidualization of human endometrial stroma and gland development is mediated through cyclic AMP (cAMP, but the role of intracellular calcium ion (Ca2+ on cAMP mediated-signaling in human endometrial stroma and glandular epithelia has not been well-characterized. The present study was designed to investigate the role of intracellular Ca2+ on cAMP mediated-decidualization and gland maturation events, which can be identified by the up-regulation of prolactin and IGF-binding protein (IGFBP1 in human endometrial stromal cells (ESCs, and cyclooxygenase 2 (COX2 and prostaglandin E2 (PGE2 and glandular epithelial EM-1 cells. Increases in decidual prolactin and IGFBP-1 transcript levels, induced by cAMP-elevating agents forskolin or dibutyryl cyclic AMP, were inhibited by Ca2+ influx into ESCs with Ca2+ ionophores (alamethicin, ionomycin in a dose-dependent manner. Conversely, inhibitors of Ca2+ influx through L-type voltage-dependent Ca2+ channel (VDCC, nifedipine and verapamil, enhanced the decidual gene expression. Furthermore, dantrolene, an inhibitor of Ca2+ release from the intracellular Ca2+ store, up-regulated prolactin and IGFBP-1 expression. Ca2+ ionophores decreased intracellular cAMP concentrations, whereas nifedipine, verapamil or dantrolene increased cAMP concentrations in ESCs. In glandular epithelial cells, similar responses in COX2 expression and PGE2 production were found when intracellular cAMP levels were up-regulated by decreases in Ca2+ concentrations. Thus, a marked decrease in cytosolic Ca2+ levels caused the elevation of cAMP concentrations, resulting in enhanced expression of implantation-related factors including decidual markers. These findings suggest that fluctuation in cytosolic Ca2+ concentrations alters intracellular cAMP levels, which then regulate differentiation of endometrial stromal and glandular epithelial cells.

  10. 21 CFR 73.1070 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... precipitated calcium carbonate (CaCO3). (2) Color additive mixtures for drug use made with calcium carbonate... precipitated calcium carbonate in the United States Pharmacopeia XX (1980). (c) Uses and restrictions. Calcium... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food...

  11. 21 CFR 184.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium carbonate. 184.1191 Section 184.1191 Food... Specific Substances Affirmed as GRAS § 184.1191 Calcium carbonate. (a) Calcium carbonate (CaCO3, CAS Reg... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation...

  12. Synthesis of platelet-activating factor by human blood platelets and leucocytes. Evidence against selective utilization of cellular ether-linked phospholipids

    NARCIS (Netherlands)

    Sturk, A.; Schaap, M. C.; Prins, A.; ten Cate, J. W.; van den Bosch, H.

    1989-01-01

    Synthesis of platelet activating factor (PAF) in blood platelet suspensions may be due to leucocyte contamination. We therefore investigated PAF synthesis in human blood platelet suspensions and granulocyte- (PMN)-enriched leucocyte suspensions upon stimulation by thrombin and Ca2+-ionophore A23187,

  13. Ethacrynic acid inhibition of histamine release from rat mast cells: effect on cellular ATP levels and thiol groups

    DEFF Research Database (Denmark)

    Johansen, Torben

    1983-01-01

    The experiments concerned the effect of ethacrynic acid (0.5 mM) on the adenosine triphosphate (ATP) content of rat mast cells and the effect on histamine release induced by the ionophore A23187 (10 microM). Ethacrynic acid decreased the ATP level of the cells in presence of antimycin A and glucose...

  14. Regulation of Schwann cell proliferation in cultured segments of the adult rat sciatic nerve

    DEFF Research Database (Denmark)

    Svenningsen, Åsa Fex; Kanje, M

    1998-01-01

    of Schwann cells. Removal of extracellular Ca2+ by addition of EGTA to the culture medium suppressed [3H] thymidine incorporation as did the calmodulin inhibitor 48/80. The Ca2+ ionophore A23187 increased incorporation. Staurosporin, an inhibitor of protein kinase C (PKC), suppressed [3H] thymidine...

  15. Calcium signalling: fishing out molecules of mitochondrial calcium transport.

    Science.gov (United States)

    Hajnóczky, György; Csordás, György

    2010-10-26

    Cellular energy metabolism, survival and death are controlled by mitochondrial calcium signals originating in the cytoplasm. Now, RNAi studies link three proteins - MICU1, NCLX and LETM1 - to the previously unknown molecular mechanism of mitochondrial calcium transport. Copyright © 2010 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    BACKGROUND: Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation off...

  17. Repair of Nerve Cell Membrance Damage by Calcium-Dependent, Membrane-Binding Proteins

    Science.gov (United States)

    2013-09-01

    membrane perturbation or disruption. Some studies have reported that annexins can influence the ability of channel- forming toxins or ionophores to... ionophore ,50,51 that readily crosses the bilayer but as evidenced here does not cause sufficient disruption of bilayer structure to allow CF to permeate

  18. Calcium, vitamin D, and your bones

    Science.gov (United States)

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

  19. Calcium Supplements: Do Men Need Them Too?

    Science.gov (United States)

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

  20. Fabrication of a highly selective cadmium (II) sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane as a supramolecular ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Ghaemi, Arezoo, E-mail: arezooghaemi@yahoo.com; Tavakkoli, Haman; Mombeni, Tayebeh

    2014-05-01

    A new cadmium (II) ion selective sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (kryptofix5) as a supramolecular carrier has been developed. The membrane solutions containing polyvinyl chloride (PVC), plasticizer, sodium tetraphenylborate (NaTPB) as a lipophilic ionic additive and kryptofix5 as an ionophore were directly coated on the surface of graphite rods. The best composition of the coated membrane (w/w%) was found to be: 30.0% PVC, 61.0% dioctyl sebacate (DOS), 6.0% NaTPB and 3.0% kryptofix5. The sensor indicates a good linear response for Cd{sup 2+} cation over a wide concentration range from 1.0 × 10{sup −5} to 1.0 × 10{sup −1} M with a Nernstian slope of 29.8 ± 0.1 mV/decade and the detection limit is 8.4 × 10{sup −6} M. The response time of the sensor is 15 s and it can be used for 7 weeks without significant drift in potential. The sensor operates in the wide pH range of 1.0–6.0. This sensor reveals a very good selectivity toward Cd{sup 2+} ion over a wide range of alkali, transition and heavy metal cations. The sensor was used as an indicator electrode for potentiometric titration of Cd{sup 2+} using sodium fluoride and ethylenediaminetetraacetic acid (EDTA) solutions with a sharp potential change that occurred at the end point. In addition, the proposed sensor was successfully used for determination of Cd{sup 2+} cation in real water samples. - Graphical abstract: Fabrication of a highly selective cadmium (II) sensor based on 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane as a supramolecular ionophore. - Highlights: • Fabrication of a novel Cd{sup 2+} selective sensor with high sensitivity and selectivity • Using fabricated sensor in a wide pH range with fast response time • Replacing expensive techniques with this low cost sensor with low detection limit • Excellent capability of this sensor for measuring Cd{sup 2+} in real samples.

  1. Stable prenucleation calcium carbonate clusters.

    Science.gov (United States)

    Gebauer, Denis; Völkel, Antje; Cölfen, Helmut

    2008-12-19

    Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation considering the formation of metastable ion clusters. We demonstrate that dissolved calcium carbonate in fact contains stable prenucleation ion clusters forming even in undersaturated solution. The cluster formation can be characterized by means of equilibrium thermodynamics, applying a multiple-binding model, which allows for structural preformation. Stable clusters are the relevant species in calcium carbonate nucleation. Such mechanisms may also be important for the crystallization of other minerals.

  2. Selective calcium ion detection with functionalized ZnO nanorods-extended gate MOSFET.

    Science.gov (United States)

    Asif, M H; Nur, O; Willander, M; Danielsson, B

    2009-07-15

    Zinc oxide nanorod-extended gate field effect transistor (MOSFET) is demonstrated for the detection of calcium (Ca(2+)) ions. ZnO nanorods were grown on the surface of a silver wire to produce an electrochemical nanosensor for selectively detecting Ca(2+). The electrochemical response from the interaction between the ZnO nanorods and Ca(2+) in an aqueous solution is coupled directly to the gate of a field effect transistor (MOSFET). The induced voltage change on the gate results in a measureable current response. In order to adapt the sensors for Ca(2+) ions measurements in biological fluids with sufficient selectivity and stability, a plastic membrane coating containing ionophores was applied on the nanorods. The sensor exhibited a linear response within the range of interest from 1 microM to 1 mM. This work demonstrates a simple technique for sensitive detection of Ca(2+) ions by efficient transfer of the chemical response directly to a standard electronic component producing a low impedance signal.

  3. Selective inhibition of neutrophil activation by the subendothelial extracellular matrix: possible role in protection of the vessel wall during diapedesis.

    Science.gov (United States)

    Matzner, Y; Vlodavsky, I; Michaeli, R I; Eldor, A

    1990-08-01

    Mobilization of circulating neutrophils toward an inflamed area involves adherence of the cells to the vascular endothelium and subsequent penetration through the endothelial cell layer without causing significant damage. To investigate the nature of a possible protective mechanism, granulocytes were incubated with the extracellular matrix (ECM) produced by cultured endothelial cells and tested for release of enzymes, chemoattractants, and free oxygen radicals. In the absence of exogenously added stimuli, the neutrophils adhered to the ECM but there was no detectable release of lysozyme, chemotactic activity, or production of O2-. In contrast, the cells readily released a heparan sulfate-degrading endoglycosidase (heparanase) to an extent comparable with that released in contact with polystyrene surfaces. Neutrophils treated with the calcium ionophore A23187 or with the peptide FMLP produced O2- to a much lesser degree when incubated in contact with ECM-coated surfaces than did those incubated in contact with uncoated polystyrene culture dishes. The ECM itself was devoid of superoxide dismutase activity. Stimulation with opsonized zymosan was not inhibited by the ECM. Experiments with isolated constituents of the ECM revealed that fibronectin but not collagen type IV or laminin could partially inhibit O2- production by Ca2+ ionophore-stimulated neutrophils. Treatment of the ECM with proteolytic enzymes, but not with heparanase, abolished its inhibitory effect on neutrophil activation. These results indicate that the subendothelial basement membrane has the capacity to inhibit release of potentially noxious agents excluding heparanase, suggesting a preferential involvement of this enzyme in neutrophil diapedesis.

  4. Oligonucleotide duplexes and multistrand assemblies with 8-aza-2'-deoxyisoguanosine: a fluorescent isoG(d) shape mimic expanding the genetic alphabet and forming ionophores.

    Science.gov (United States)

    Jiang, Dawei; Seela, Frank

    2010-03-24

    8-Aza-2'-deoxyisoguanosine (4) is the first fluorescent shape mimic of 2'-deoxyisoguanosine (1a); its fluorescence is stronger in alkaline medium than under neutral conditions. Nucleoside 4, which was synthesized from 8-aza-2'-deoxyguanosine via a 4,6-diamino intermediate after selective deamination, was incorporated in oligodeoxyribonucleotides using phosphoramidite 11. Duplexes with 4 x m(5)iC(d) (5-methyl-2'-deoxyisocytidine) base pairs are more stable than those incorporating dG-dC pairs, thereby expanding the genetic alphabet by a fluorescent orthogonal base pair. As demonstrated by T(m) measurements, the base pair stability decreases in the order m(5)iC(d) x 4 > dG x 4 > dT x 4 > or = dC x 4 > dA x 4. A better base pairing selectivity of 4 against the canonical nucleosides dT, dC, dA, and dG is observed than for the degenerated base pairing of 1a. The base pair stability changes can be monitored by nucleobase anion fluorescence sensing. The fluorescence change correlates to the DNA base pair stability. Oligonucleotide 5'-d(T(4)4(4)T(4)) (22), containing short runs of nucleoside 4, forms stable multistranded assemblies (ionophores) with K(+) in the central cavity. They are quite stable at elevated temperature but are destroyed at high pH value.

  5. Calcium metabolism & hypercalcemia in adults.

    Science.gov (United States)

    Lumachi, F; Motta, R; Cecchin, D; Ave, S; Camozzi, V; Basso, S M M; Luisetto, G

    2011-01-01

    Calcium is essential for many metabolic process, including nerve function, muscle contraction, and blood clotting. The metabolic pathways that contribute to maintain serum calcium levels are bone remodeling processes, intestinal absorption and secretion, and renal handling, but hypercalcemia occurs when at least 2 of these 3 metabolic pathways are altered. Calcium metabolism mainly depends on the activity of parathyroid hormone (PTH). Its secretion is strictly controlled by the ionized serum calcium levels through a negative feed-back, which is achieved by the activation of calcium-sensing receptors (CaSRs) mainly expressed on the surface of the parathyroid cells. The PTH receptor in bone and kidney is now referred as PTHR1. The balance of PTH, calcitonin, and vitamin D has long been considered the main regulator of calcium metabolism, but the function of other actors, such as fibroblast growth factor-23 (FGF-23), Klotho, and TPRV5 should be considered. Primary hyperparathyroidism and malignancy are the most common causes of hypercalcemia, accounting for more than 90% of cases. Uncontrolled hypercalcemia may cause renal impairment, both temporary (alteration of renal tubular function) and progressive (relapsing nephrolithiasis), leading to a progressive loss of renal function, as well as severe bone diseases, and heart damages. Advances in the understanding of all actors of calcium homeostasis will be crucial, having several practical consequences in the treatment and prevention of hypercalcemia. This would allow to move from a support therapy, sometimes ineffective, to a specific and addressed therapy, especially in patients with chronic hypercalcemic conditions unsuitable for surgery.

  6. Free cytosolic calcium and secretagogue-stimulated initial pancreatic exocrine secretion.

    Science.gov (United States)

    Krims, P E; Pandol, S J

    1988-01-01

    In order to establish the role of secretagogue-induced changes in free cytosolic Ca2+ ([Ca2+]i) in pancreatic enzyme secretion, we measured the effects of carbachol, cholecystokinin-octapeptide (CCK-OP), bombesin, substance P, and bromo-A23187 on amylase release and [Ca2+]i in guinea pig pancreatic acini loaded with the Ca2+-selective fluorescent indicator, fura-2. Evaluation of time courses and dose-response curves indicated that carbachol, CCK-OP, bombesin, and substance P cause extracellular Ca2+-independent transient increases in [Ca2+]i and transient bursts in amylase release (initial secretion). The potencies for the secretagogues to increase [Ca2+]i and initial amylase release were similar. Bromo-A23187 also caused an extracellular Ca2+-independent transient increase in [Ca2+]i and amylase release. In the absence of extracellular Ca2+, sequential additions of substance P followed by carbachol caused transient increases in [Ca2+]i correlating with transient bursts in amylase release. In contrast, in acini first treated with carbachol, the ability of substance P to increase [Ca2+]i and amylase release was blocked. Sustained secretion caused by the secretagogues was dependent on extracellular Ca2+ but occurred at basal [Ca2+]i. Increasing [Ca2+]i during the sustained phase of stimulation by increasing the extracellular Ca2+ concentration or with bromo-A23187 did not increase the rate of sustained secretion.

  7. Calcium and Calcium Supplements: Achieving the Right Balance

    Science.gov (United States)

    ... Duyff RL. American Dietetic Association Complete Food and Nutrition Guide. 4th ed. Hoboken, N.J.: John Wiley & Sons; 2012:140. Rosen HN. Calcium and vitamin D supplementation in osteoporosis. http://www.uptodate.com/home/index. ...

  8. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001

    Science.gov (United States)

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

    1987-01-01

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

  9. Activation of Src and release of intracellular calcium by phosphatidic acid during Xenopus laevis fertilization

    Science.gov (United States)

    Bates, Ryan C.; Fees, Colby P.; Holland, William L.; Winger, Courtney C.; Batbayar, Khulan; Ancar, Rachel; Bergren, Todd; Petcoff, Douglas; Stith, Bradley J.

    2014-01-01

    We report a new step in the fertilization in Xenopus laevis which has been found to involve activation of Src tyrosine kinase to stimulate phospholipase C-γ (PLC- γ) which increases inositol 1,4,5-trisphosphate (IP3) to release intracellular calcium ([Ca]i). Molecular species analysis and mass measurements suggested that sperm activate phospholipase D (PLD) to elevate phosphatidic acid (PA). We now report that PA mass increased 2.7 fold by 1 minute after insemination and inhibition of PA production by two methods inhibited activation of Src and PLCγ, increased [Ca]i and other fertilization events. As compared to 14 other lipids, PA strongly bound Xenopus Src but not PLCγ. Addition of synthetic PA activated egg Src (an action requiring intact lipid rafts) and PLCγ as well as doubling the amount of PLCγ in rafts. In the absence of elevated [Ca]i, PA addition elevated IP3 mass to levels equivalent to that induced by sperm (but twice that achieved by calcium ionophore). Finally, PA induced [Ca]i release that was blocked by an IP3 receptor inhibitor. As only PLD1b message was detected, and Western blotting did not detect PLD2, we suggest that sperm activate PLD1b to elevate PA which then binds to and activates Src leading to PLCγ stimulation, IP3 elevation and [Ca]i release. Due to these and other studies, PA may also play a role in membrane fusion events such as sperm-egg fusion, cortical granule exocytosis, the elevation of phosphatidylinositol 4,5-bisphosphate and the large, late increase in sn 1,2-diacylglycerol in fertilization. PMID:24269904

  10. 21 CFR 184.1187 - Calcium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005.... Calcium alginate is prepared by the neutralization of purified alginic acid with appropriate pH control...

  11. Extracellular and Intracellular Regulation of Calcium Homeostasis

    Directory of Open Access Journals (Sweden)

    Felix Bronner

    2001-01-01

    Full Text Available An organism with an internal skeleton must accumulate calcium while maintaining body fluids at a well-regulated, constant calcium concentration. Neither calcium absorption nor excretion plays a significant regulatory role. Instead, isoionic calcium uptake and release by bone surfaces causes plasma calcium to be well regulated. Very rapid shape changes of osteoblasts and osteoclasts, in response to hormonal signals, modulate the available bone surfaces so that plasma calcium can increase when more low-affinity bone calcium binding sites are made available and can decrease when more high-affinity binding sites are exposed. The intracellular free calcium concentration of body cells is also regulated, but because cells are bathed by fluids with vastly higher calcium concentration, their major regulatory mechanism is severe entry restriction. All cells have a calcium-sensing receptor that modulates cell function via its response to extracellular calcium. In duodenal cells, the apical calcium entry structure functions as both transporter and a vitamin D–responsive channel. The channel upregulates calcium entry, with intracellular transport mediated by the mobile, vitamin D–dependent buffer, calbindin D9K, which binds and transports more than 90% of the transcellular calcium flux. Fixed intracellular calcium binding sites can, like the body's skeleton, take up and release calcium that has entered the cell, but the principal regulatory tool of the cell is restricted entry.

  12. Calcium phosphates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-01

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

  13. Polysulfide calcium as multyfunctional product

    Directory of Open Access Journals (Sweden)

    G. Abramova

    2012-12-01

    Full Text Available A modified method of producing of polysulfide calcium, the influence of various factors on the degree of polysulfide of product, as well as possible directions for its use as a multifunctional compound were considered.

  14. [Calcium metabolism after the menopause].

    Science.gov (United States)

    Kanovitch, D; Klotz, H P

    1976-02-16

    The authors recall the antagonism between estradiol and parathormone. Estradiol tends to lower serum calcium and fix calcium in the bones as shown by one of us 25 years ago. The mechanism of this action of estrogen on calcium metabolism has been determined by numerous authors but some points are still not clear, e.g. the interferences between estrogen and calcitonin. Classically, parathormone is known to increase bony reabsorption and raise serum calcium. After the menopause the gradual reduction in estradiol secretion leads to post-menopausal osteoporosis. It is better to administer estrogens prophylactically to women after the menopause provided a cervical smear and mammography have been carried out to eliminate latent carcinoma of the breast or uterine cervix.

  15. Calcium-sensing beyond neurotransmitters

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Han, Weiping

    2009-01-01

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

  16. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt. 172.330 Section 172.330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  17. Calcium affects on vascular endpoints

    Directory of Open Access Journals (Sweden)

    Patel Vaishali B

    2012-03-01

    Full Text Available Abstract Calcium is one of the most abundant minerals in the body and its metabolism is one of the basic biologic processes in humans. Although historically linked primarily to bone structural development and maintenance, calcium is now recognized as a key component of many physiologic pathways necessary for optimum health including cardiovascular, neurological, endocrine, renal, and gastrointestinal systems. A recent meta-analysis published in August 2011 showed a potential increase in cardiovascular events related to calcium supplementation. The possible mechanism of action of this correlation has not been well elucidated. This topic has generated intense interest due to the widespread use of calcium supplements, particularly among the middle aged and elderly who are at the most risk from cardiac events. Prior studies did not control for potential confounding factors such as the use of statins, aspirin or other medications. These controversial results warrant additional well-designed studies to investigate the relationship between calcium supplementation and cardiovascular outcomes. The purpose of this review is to highlight the current literature in regards to calcium supplementation and cardiovascular health; and to identify areas of future research.

  18. Effects of an Ionophore Coccidiostat (Monensin or Salinomycin, Sodium or Potassium Bicarbonate, or Both, and Bacitracin Methylene Disalicylate in Broiler Chicken Diets

    Directory of Open Access Journals (Sweden)

    Hooge DM

    2000-01-01

    Full Text Available Peterson x Arbor Acres chicks were grown on used litter to 45 or 46 days of age in three pen trials. Coccidial inoculations were given by water at 14 days of age. Sodium bicarbonate (SBC; 0.20% or potassium bicarbonate (PBC; 0.14% was added to broiler chicken diets containing monensin (MON; 110 mg/kg or salinomycin (SAL; 66 mg/kg in Experiment 1. In Experiment 2, using SAL (55 mg/kg, three dietary bicarbonate treatments (SBC, 0.20%; PBC, 0.20%; or SBC + PBC 0.10% each were tested with or without BMD R (55 mg/kg. Diets differing in SAL, BMD R, and SBC levels were evaluated in Experiment 3. Beneficial interaction was found between ionophores and bicarbonates for mortality (lower when SBC or PBC and MON in Experiment 1. For main effects, in Experiment 1 PBC with MON or SAL improved body weight, feed conversion ratio and mortality. SAL improved weight, feed conversion ratio and mortality compared to MON. In Experiment 2, PBC with SAL improved weight, coccidial lesion score, feed conversion ratio and mortality across two levels of BMD R. The PBC and SBC were equally effective in Experiment 1, but PBC was about 0 to 40% as effective as SBC, depending on parameter in Experiment 2. Half levels of SBC plus PBC generally gave intermediate results between control and SBC. SBC with MON or SAL lowered mortalities, coccidial lesion scores, and feed conversion ratios (Experiments 1 and 2, and increased body weight (Experiment 2. In Experiment 3, BMD R in all feeds improved body weight and feed conversion versus in starter feed only, and SBC with SAL and BMD R improved all performance parameters.

  19. Zn(2+ inhibits coronavirus and arterivirus RNA polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture.

    Directory of Open Access Journals (Sweden)

    Aartjan J W te Velthuis

    Full Text Available Increasing the intracellular Zn(2+ concentration with zinc-ionophores like pyrithione (PT can efficiently impair the replication of a variety of RNA viruses, including poliovirus and influenza virus. For some viruses this effect has been attributed to interference with viral polyprotein processing. In this study we demonstrate that the combination of Zn(2+ and PT at low concentrations (2 µM Zn(2+ and 2 µM PT inhibits the replication of SARS-coronavirus (SARS-CoV and equine arteritis virus (EAV in cell culture. The RNA synthesis of these two distantly related nidoviruses is catalyzed by an RNA-dependent RNA polymerase (RdRp, which is the core enzyme of their multiprotein replication and transcription complex (RTC. Using an activity assay for RTCs isolated from cells infected with SARS-CoV or EAV--thus eliminating the need for PT to transport Zn(2+ across the plasma membrane--we show that Zn(2+ efficiently inhibits the RNA-synthesizing activity of the RTCs of both viruses. Enzymatic studies using recombinant RdRps (SARS-CoV nsp12 and EAV nsp9 purified from E. coli subsequently revealed that Zn(2+ directly inhibited the in vitro activity of both nidovirus polymerases. More specifically, Zn(2+ was found to block the initiation step of EAV RNA synthesis, whereas in the case of the SARS-CoV RdRp elongation was inhibited and template binding reduced. By chelating Zn(2+ with MgEDTA, the inhibitory effect of the divalent cation could be reversed, which provides a novel experimental tool for in vitro studies of the molecular details of nidovirus replication and transcription.

  20. A novel barium polymeric membrane sensor for selective determination of barium and sulphate ions based on the complex ion associate barium(II)-Rose Bengal as neutral ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A.M. [Genetic Engineering and Biotechnology Research Institute (GEBRI), Minufiya University, Sadat City (Egypt); El-Shahawi, M.S. [Chemistry Department, Faculty of Science at Damiatta, Mansoura University, Damiatta, Dumyat 34517 (Egypt)]. E-mail: mohammad_el_shahawi@yahoo.co.uk; Abdel-Azeem, M. [Chemistry Department, Faculty of Science at Damiatta, Mansoura University, Damiatta, Dumyat 34517 (Egypt)

    2006-01-12

    A simple, long life, rapid response and sensitive barium(II)-PVC membrane sensor that typically follows Nernstian behavior has been developed for the assay of barium(II) ions. The developed sensor has been made by incorporating the complex ion associate of barium(II)-Rose Bengal (Ba-RB) as an ionophore into a plasticized PVC matrix. The sensor is stable and exhibited fast potential response of 20 s and gave a good linear response with a Nernstian slope of 28.5 {+-} 0.4 mV/decade of activity within the concentration range 5 x 10{sup -5} to 10{sup -1} M over a wide range of pH 4.5-10.0 for barium(II) ions. The developed sensor showed comparatively good selectivity for barium(II) ions with respect to other alkali, alkaline earth, transition and heavy metal ions. The plasticizer o-nitrophenyloctyl ether controlled significantly the calibration slope and the lifetime of the fabricated sensor. The proposed sensor was used successfully for the analysis of barium(II) ions in wastewater samples and in lithophone pigment with excellent recovery percentages in the range 98.9-99.8 {+-} 1.6%. The determination of sulphate in fresh and potable water samples with the developed sensor has been also achieved successfully. The described sensor provides a reliable means with good correlation with the data obtained by atomic absorption spectrometry (AAS) and other spectrophotometric methods for the analysis of trace amounts of barium(II) and/or sulphate ions in different matrices.

  1. Zn(2+) inhibits coronavirus and arterivirus RNA polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture.

    Science.gov (United States)

    te Velthuis, Aartjan J W; van den Worm, Sjoerd H E; Sims, Amy C; Baric, Ralph S; Snijder, Eric J; van Hemert, Martijn J

    2010-11-04

    Increasing the intracellular Zn(2+) concentration with zinc-ionophores like pyrithione (PT) can efficiently impair the replication of a variety of RNA viruses, including poliovirus and influenza virus. For some viruses this effect has been attributed to interference with viral polyprotein processing. In this study we demonstrate that the combination of Zn(2+) and PT at low concentrations (2 µM Zn(2+) and 2 µM PT) inhibits the replication of SARS-coronavirus (SARS-CoV) and equine arteritis virus (EAV) in cell culture. The RNA synthesis of these two distantly related nidoviruses is catalyzed by an RNA-dependent RNA polymerase (RdRp), which is the core enzyme of their multiprotein replication and transcription complex (RTC). Using an activity assay for RTCs isolated from cells infected with SARS-CoV or EAV--thus eliminating the need for PT to transport Zn(2+) across the plasma membrane--we show that Zn(2+) efficiently inhibits the RNA-synthesizing activity of the RTCs of both viruses. Enzymatic studies using recombinant RdRps (SARS-CoV nsp12 and EAV nsp9) purified from E. coli subsequently revealed that Zn(2+) directly inhibited the in vitro activity of both nidovirus polymerases. More specifically, Zn(2+) was found to block the initiation step of EAV RNA synthesis, whereas in the case of the SARS-CoV RdRp elongation was inhibited and template binding reduced. By chelating Zn(2+) with MgEDTA, the inhibitory effect of the divalent cation could be reversed, which provides a novel experimental tool for in vitro studies of the molecular details of nidovirus replication and transcription.

  2. Determination of polyether ionophores in urban sewage sludge by pressurised liquid extraction and liquid chromatography-tandem mass spectrometry: study of different clean-up strategies.

    Science.gov (United States)

    Herrero, P; Borrull, F; Marcé, R M; Pocurull, E

    2013-04-12

    A method for the determination of five polyether ionophores in urban sewage sludge has been developed. The extraction of compounds was performed by pressurised liquid extraction using acetone, while florisil was used for in-cell clean-up to minimise the matrix effect in the sludge extracts. An amide polar-embedded reversed-phase column was used for the chromatographic separation with a rapid-resolution liquid chromatograph coupled to a tandem mass spectrometer. Moreover, several clean-up strategies such as in-cell and on-cell clean-up and solid-phase extraction clean-up, among others, were tested and their results are discussed in the present paper. Recoveries (10 and 250 μg/kg in dry weight (d.w.), n=6) were close to 90%, repeatability and reproducibility (%RSD, 10 and 250 μg/kg (d.w.), n=6) were less than 10% and 12%, respectively. Limits of detection (LODs) and limits of quantification (LOQs) ranged between 0.5 and 1 μg/kg (d.w.) and between 1 and 5 μg/kg (d.w.), respectively. The method was applied to samples collected in five sewage treatment plants in Catalonia. Monensin and narasin were determined in some sludge samples at concentrations from

  3. Zn2+ Inhibits Coronavirus and Arterivirus RNA Polymerase Activity In Vitro and Zinc Ionophores Block the Replication of These Viruses in Cell Culture

    Science.gov (United States)

    te Velthuis, Aartjan J. W.; van den Worm, Sjoerd H. E.; Sims, Amy C.; Baric, Ralph S.; Snijder, Eric J.; van Hemert, Martijn J.

    2010-01-01

    Increasing the intracellular Zn2+ concentration with zinc-ionophores like pyrithione (PT) can efficiently impair the replication of a variety of RNA viruses, including poliovirus and influenza virus. For some viruses this effect has been attributed to interference with viral polyprotein processing. In this study we demonstrate that the combination of Zn2+ and PT at low concentrations (2 µM Zn2+ and 2 µM PT) inhibits the replication of SARS-coronavirus (SARS-CoV) and equine arteritis virus (EAV) in cell culture. The RNA synthesis of these two distantly related nidoviruses is catalyzed by an RNA-dependent RNA polymerase (RdRp), which is the core enzyme of their multiprotein replication and transcription complex (RTC). Using an activity assay for RTCs isolated from cells infected with SARS-CoV or EAV—thus eliminating the need for PT to transport Zn2+ across the plasma membrane—we show that Zn2+ efficiently inhibits the RNA-synthesizing activity of the RTCs of both viruses. Enzymatic studies using recombinant RdRps (SARS-CoV nsp12 and EAV nsp9) purified from E. coli subsequently revealed that Zn2+ directly inhibited the in vitro activity of both nidovirus polymerases. More specifically, Zn2+ was found to block the initiation step of EAV RNA synthesis, whereas in the case of the SARS-CoV RdRp elongation was inhibited and template binding reduced. By chelating Zn2+ with MgEDTA, the inhibitory effect of the divalent cation could be reversed, which provides a novel experimental tool for in vitro studies of the molecular details of nidovirus replication and transcription. PMID:21079686

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

    National Research Council Canada - National Science Library

    Pochet, Roland; Donato, Rosario

    2000-01-01

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

  5. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

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

    2010-01-01

    Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX....... Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon...... appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1 s...

  6. Calcium metabolism and cardiovascular function after spaceflight

    Science.gov (United States)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; hide

    2002-01-01

    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P parathyroid hormone levels (P animals (P = 0.057). However, mean arterial pressure was elevated (P animals fed low- compared with high-calcium diets (P parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  7. [Regulatory mechanism of calcium metabolism.

    Science.gov (United States)

    Ozono, Keiichi

    It is often difficult for terrestrial animals to take enough calcium. To maintain serum or extracellular calcium levels is very important for muscle and nerve function. Two major regulators to increase the serum calcium levels are parathyroid hormone(PTH)and vitamin D. PTH binds to the G protein coupling receptor, PTH1R, and increases intracellular cAMP levels. Impirement in the PTH signalling causes many diseases such as pseudohypoparathyroidism and acrodysostosis with hormone resistance. Vitamin D is activated to 1,25-dihydroxyvitamin D[1,25(OH)2D]by two steps of hydroxylation which occurs in the Liver and Kidney. Then, 1,25(OH)2D binds to vitamin D receptor(VDR), which works as a ligand-dependent transcription factor. Hypocalcemia and hypercalcemia are caused by various disorders including abnormal regulation of PTH and vitamin D production and their signal transduction.

  8. Calcium signaling and cell proliferation.

    Science.gov (United States)

    Pinto, Mauro Cunha Xavier; Kihara, Alexandre Hiroaki; Goulart, Vânia A M; Tonelli, Fernanda M P; Gomes, Katia N; Ulrich, Henning; Resende, Rodrigo R

    2015-11-01

    Cell proliferation is orchestrated through diverse proteins related to calcium (Ca(2+)) signaling inside the cell. Cellular Ca(2+) influx that occurs first by various mechanisms at the plasma membrane, is then followed by absorption of Ca(2+) ions by mitochondria and endoplasmic reticulum, and, finally, there is a connection of calcium stores to the nucleus. Experimental evidence indicates that the fluctuation of Ca(2+) from the endoplasmic reticulum provides a pivotal and physiological role for cell proliferation. Ca(2+) depletion in the endoplasmatic reticulum triggers Ca(2+) influx across the plasma membrane in an phenomenon called store-operated calcium entries (SOCEs). SOCE is activated through a complex interplay between a Ca(2+) sensor, denominated STIM, localized in the endoplasmic reticulum and a Ca(2+) channel at the cell membrane, denominated Orai. The interplay between STIM and Orai proteins with cell membrane receptors and their role in cell proliferation is discussed in this review. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Differential phospholipid-labeling suggests two subtypes of phospholipase D in rat Leydig cells

    DEFF Research Database (Denmark)

    Lauritzen, L.; Hansen, Harald S.

    1995-01-01

    Cho). The [H] phosphatidylethanol formation in response to 4ß-phorbol 12-myristate 13-acetate (PMA), sphingosine, or Ca-ionophore A23187, was lower when Leydig cells were labeled with 1-O-[H]alkyl lysoPtdCho compared with the responses when [H]myristic acid was employed. In contrast, the results...... for the receptor agonists (vasopressin, bradykinin, and lysophosphatidic acid), using the two labels, showed mole consistency. Thus, the PLD-activity induced by PMA, sphingosine, or A23187 has a more selective substrate range (i.e. mainly acyl-linked PtdCho) than the PLD-activity stimulated via a receptor. Our...

  10. Calcium regulation of muscle contraction.

    Science.gov (United States)

    Szent-Györgyi, A G

    1975-07-01

    Calcium triggers contraction by reaction with regulatory proteins that in the absence of calcium prevent interaction of actin and myosin. Two different regulatory systems are found in different muscles. In actin-linked regulation troponin and tropomyosin regulate actin by blocking sites on actin required for complex formation with myosin; in myosin-linked regulation sites on myosin are blocked in the absence of calcium. The major features of actin control are as follows: there is a requirement for tropomyosin and for a troponin complex having three different subunits with different functions; the actin displays a cooperative behavior; and a movement of tropomyosin occurs controlled by the calcium binding on troponin. Myosin regulation is controlled by a regulatory subunit that can be dissociated in scallop myosin reversibly by removing divalent cations with EDTA. Myosin control can function with pure actin in the absence of tropomyosin. Calcium binding and regulation of molluscan myosins depend on the presence of regulatory light chains. It is proposed that the light chains function by sterically blocking myosin sites in the absence of calcium, and that the "off" state of myosin requires cooperation between the two myosin heads. Both myosin control and actin control are widely distributed in different organisms. Many invertebrates have muscles with both types of regulation. Actin control is absent in the muscles of molluscs and in several minor phyla that lack troponin. Myosin control is not found in striated vertebrate muscles and in the fast muscles of crustacean decapods, although regulatory light chains are present. While in vivo myosin control may not be excluded from vertebrate striated muscles, myosin control may be absent as a result of mutations of the myosin heavy chain.

  11. Can total cardiac calcium predict the coronary calcium score?

    Science.gov (United States)

    Pressman, Gregg S; Crudu, Vitalie; Parameswaran-Chandrika, Anoop; Romero-Corral, Abel; Purushottam, Bhaskar; Figueredo, Vincent M

    2011-01-21

    Mitral annular calcification (MAC) shares the same risk factors as atherosclerosis and is associated with coronary artery disease as well as cardiovascular events. However, sensitivity and positive predictive value are low. We hypothesized that a global echocardiographic calcium score would better predict coronary atherosclerotic burden, as assessed by coronary artery calcium score (CAC), than MAC alone. An echocardiographic score was devised to measure global cardiac calcification in a semi-quantitative manner; this included calcification in the aortic valve and root, the mitral valve and annulus, and the sub-mitral apparatus. This score, and a simplified version, were compared with a similar calcification score by CT scan, as well as the CAC. There was a good correlation between the two global calcification scores; the echocardiographic score also correlated with CAC. Using CAC >400 as a measure of severe coronary atherosclerosis, an echocardiographic score ≥5 had a positive predictive value of 60%. Importantly, the simplified score performed equally well (≥3 had a positive predictive value of 62%). Global cardiac calcification, assessed by CT scan or echocardiography, correlates with the extent of coronary calcium. A semi-quantitative calcium score can be easily applied during routine echocardiographic interpretation and can alert the reader to the possibility of severe coronary atherosclerosis. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

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

    Indian Academy of Sciences (India)

    stoichiometric quantities of aqueous solutions of calcium maleate, iron(III) maleate and maleic acid. The reaction mixture was concentrated on a water bath until a brown coloured product formed after the addition of excess of acetone. The complex was vacuum dried and its identity was established by chemical analysis.

  13. Calcium ferrite formation from the thermolysis of calcium tris ...

    Indian Academy of Sciences (India)

    Various physico-chemical techniques i.e. TG, DTG, DTA, Mössbauer, XRD, IR etc have been used to study the decomposition behaviour from ambient to 900°C and ferrite formation. Three consecutive decomposition steps leading to the formation of -Fe2O3 and calcium carbonate have been observed at various stages of ...

  14. 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.

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

    Science.gov (United States)

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

    2009-01-01

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

  16. Calcium release from experimental dental materials.

    Science.gov (United States)

    Okulus, Zuzanna; Buchwald, Tomasz; Voelkel, Adam

    2016-11-01

    The calcium release from calcium phosphate-containing experimental dental restorative materials was examined. The possible correlation of ion release with initial calcium content, solubility and degree of curing (degree of conversion) of examined materials was also investigated. Calcium release was measured with the use of an ion-selective electrode in an aqueous solution. Solubility was established by the weighing method. Raman spectroscopy was applied for the determination of the degree of conversion, while initial calcium content was examined with the use of energy-dispersive spectroscopy. For examined materials, the amount of calcium released was found to be positively correlated with solubility and initial calcium content. It was also found that the degree of conversion does not affect the ability of these experimental composites to release calcium ions. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim

    2014-01-01

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

  18. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

    ... Bone Health Featured Resource Find an Endocrinologist Search Vitamin D, Calcium, and Bone Health March 2012 Download ... also helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin ...

  19. Antimicrobial agent triclosan is a proton ionophore uncoupler of mitochondria in living rat and human mast cells and in primary human keratinocytes.

    Science.gov (United States)

    Weatherly, Lisa M; Shim, Juyoung; Hashmi, Hina N; Kennedy, Rachel H; Hess, Samuel T; Gosse, Julie A

    2016-06-01

    Triclosan (TCS) is an antimicrobial used widely in hospitals and personal care products, at ~10 mm. Human skin efficiently absorbs TCS. Mast cells are ubiquitous key players both in physiological processes and in disease, including asthma, cancer and autism. We previously showed that non-cytotoxic levels of TCS inhibit degranulation, the release of histamine and other mediators, from rat basophilic leukemia mast cells (RBL-2H3), and in this study, we replicate this finding in human mast cells (HMC-1.2). Our investigation into the molecular mechanisms underlying this effect led to the discovery that TCS disrupts adenosine triphosphate (ATP) production in RBL-2H3 cells in glucose-free, galactose-containing media (95% confidence interval EC50 = 7.5-9.7 µm), without causing cytotoxicity. Using these same glucose-free conditions, 15 µm TCS dampens RBL-2H3 degranulation by 40%. The same ATP disruption was found with human HMC-1.2 cells (EC50 4.2-13.7 µm), NIH-3 T3 mouse fibroblasts (EC50 4.8-7.4 µm) and primary human keratinocytes (EC50 3.0-4.1 µm) all with no cytotoxicity. TCS increases oxygen consumption rate in RBL-2H3 cells. Known mitochondrial uncouplers (e.g., carbonyl cyanide 3-chlorophenylhydrazone) previously were found to inhibit mast cell function. TCS-methyl, which has a methyl group in place of the TCS ionizable proton, affects neither degranulation nor ATP production at non-cytotoxic doses. Thus, the effects of TCS on mast cell function are due to its proton ionophore structure. In addition, 5 µm TCS inhibits thapsigargin-stimulated degranulation of RBL-2H3 cells: further evidence that TCS disrupts mast cell signaling. Our data indicate that TCS is a mitochondrial uncoupler, and TCS may affect numerous cell types and functions via this mechanism. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Selectivity of bis(calix[4]diquinone) ionophores towards metal ions in solvent dimethylsulfoxide: a molecular mechanics and molecular dynamics study.

    Science.gov (United States)

    Felix, Vitor; Drew, Michael G B; Webber, Philip R A; Beer, Paul D

    2006-01-28

    Molecular modelling studies have been carried out on two bis(calix[4]diquinone) ionophores, each created from two (calix[4]diquinone)arenes bridged at their bottom rims via alkyl chains (CH(2))(n), 1: n = 3, 2; n = 4, in order to understand the reported selectivity of these ligands towards different sized metal ions such as Na(+), K(+), Rb(+), and Cs(+) in dmso solution. Conformational analyses have been carried out which show that in the lowest energy conformations of the two macrocycles, the individual calix[4]diquinones exhibit a combination of partial cone, 1,3-alternate and cone conformations. The interactions of these alkali metals with the macrocycles have been studied in the gas phase and in a periodic box of solvent dmso by molecular mechanics and molecular dynamics calculations. Molecular mechanics calculations have been carried out on the mode of entry of the ions into the macrocycles and suggest that this is likely to occur from the side of the central cavity, rather than through the main axis of the calix[4]diquinones. There are energy barriers of ca. 19 kcal mol(-1) for this entry path in the gas phase, but in solution no energy barrier is found. Molecular dynamics simulations show that in both 1 and 2, though particularly in the latter macrocycle, one or two solvent molecules are bonded to the metal throughout the course of the simulation, often to the exclusion of one or more of the ether oxygen atoms. By contrast the carbonyl oxygen atoms remain bonded to the metal atoms throughout with bond lengths that remain significantly less than those to the ether oxygen atoms. Free energy perturbation studies have been carried out in dmso and indicate that for 1, the selectivity follows the order Rb(+) approximately K(+) > Cs(+) > Na(+), which is partially in agreement with the experimental results. The energy differences are small and indeed the ratio between stability constants found for Cs(+) and K(+) complexes is only 0.60, showing that has only a slight

  1. 21 CFR 184.1229 - Calcium stearate.

    Science.gov (United States)

    2010-04-01

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

  2. Bioactive and Hemocompatible Calcium Sulphoaluminate Cement

    OpenAIRE

    Acuña-Gutiérrez, Iván Omar; Escobedo-Bocardo, José Concepción; Almanza-Robles, José Manuel; Cortés-Hernández, Dora Alicia; Saldívar-Ramírez, Mirna María Guadalupe; Reséndiz-Hernández, Perla Janet; Zugasti-Cruz, Alejandro

    2015-01-01

    Calcium sulphoaluminate cement (CSAC) is an attractive candidate for biomedical applications due to its appropriate mechanical properties and high calcium content. In vitro bioactivity and hemocompatibility of calcium sulphoaluminate cement were assessed. The cement was prepared from a mixture of calcium sulphoaluminate (CSA) clinker, gypsum and water. Cement samples were immersed in a simulated body fluid (SBF) at 37 °C for different periods of time (7, 14 and 21 days). The analyses of these...

  3. Calcium Balance in Chronic Kidney Disease

    OpenAIRE

    Hill Gallant, Kathleen M.; Spiegel, David M.

    2017-01-01

    Purpose of Review The kidneys play a critical role in the balance between the internal milieu and external environment. Kidney failure is known to disrupt a number of homeostatic mechanisms that control serum calcium and normal bone metabolism. However, our understanding of calcium balance throughout the stages of chronic kidney disease is limited and the concept of balance itself, especially with a cation as complex as calcium, is often misunderstood. Both negative and positive calcium balan...

  4. Calcium Balance in Chronic Kidney Disease.

    Science.gov (United States)

    Hill Gallant, Kathleen M; Spiegel, David M

    2017-06-01

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

  5. Electrochemical Induced Calcium Phosphate Precipitation

    NARCIS (Netherlands)

    Lei, Yang; Song, Bingnan; Weijden, van der Renata D.; Saakes, M.; Buisman, Cees J.N.

    2017-01-01

    Phosphorus (P) is an essential nutrient for living organisms and cannot be replaced or substituted. In this paper, we present a simple yet efficient membrane free electrochemical system for P removal and recovery as calcium phosphate (CaP). This method relies on in situ formation of hydroxide

  6. Measuring calcium, potassium, and nitrate in plant nutrient solutions using ion-selective electrodes in hydroponic greenhouse of some vegetables.

    Science.gov (United States)

    Vardar, Gökay; Altıkatoğlu, Melda; Ortaç, Deniz; Cemek, Mustafa; Işıldak, İbrahim

    2015-01-01

    Generally, the life cycle of plants depends on the uptake of essential nutrients in a balanced manner and on toxic elements being under a certain concentration. Lack of control of nutrient levels in nutrient solution can result in reduced plant growth and undesired conditions such as blossom-end rot. In this study, sensitivity and selectivity tests for various polyvinylchloride (PVC)-based ion-selective membranes were conducted to identify those suitable for measuring typical concentration ranges of macronutrients, that is, NO(3-), K(+), and Ca(2+), in hydroponic solutions. The sensitivity and selectivity of PVC-membrane-based ion-selective sensors prepared with tetradodecylammoniumnitrate for NO(3-), valinomycin for K(+), and Ca ionophore IV for Ca(2+) were found to be satisfactory for measuring NO(3-), K(+), and Ca(2+) ions in nutrient solutions over typical ranges of hydroponic concentrations. Potassium, calcium, and nitrate levels that were utilized by cucumber and tomato seedlings in the greenhouse were different. The findings show that tomato plants consumed less amounts of nitrate than cucumber plants over the first 2 months of their growth. We also found that the potassium intake was higher than other nutritional elements tested for all plants. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

  7. Sucralose, an activator of the glucose-sensing receptor, increases ATP by calcium-dependent and -independent mechanisms.

    Science.gov (United States)

    Li, Longfei; Ohtsu, Yoshiaki; Nakagawa, Yuko; Masuda, Katsuyoshi; Kojima, Itaru

    2016-08-31

    Sucralose is an artificial sweetener and activates the glucose-sensing receptor expressed in pancreatic β-cells. Although sucralose does not enter β-cells nor acts as a substrate for glucokinase, it induces a marked elevation of intracellular ATP ([ATP]c). The present study was conducted to identify the signaling pathway responsible for the elevation of [ATP]c induced by sucralose. Previous studies have shown that sucralose elevates cyclic AMP (cAMP), activates phospholipase C (PLC) and stimulates Ca(2+) entry by a Na(+)-dependent mechanism in MIN6 cells. The addition of forskolin induced a marked elevation of cAMP, whereas it did not affect [ATP]c. Carbachol, an activator of PLC, did not increase [ATP]c. In addition, activation of protein kinase C by dioctanoylglycerol did not affect [ATP]c. In contrast, nifedipine, an inhibitor of the voltage-dependent Ca(2+) channel, significantly reduced [ATP]c response to sucralose. Removal of extracellular Na(+) nearly completely blocked sucralose-induced elevation of [ATP]c. Stimulation of Na(+) entry by adding a Na(+) ionophore monensin elevated [ATP]c. The monensin-induced elevation of [ATP]c was only partially inhibited by nifedipine and loading of BAPTA, both of which completely abolished elevation of [Ca(2+)]c. These results suggest that Na(+) entry is critical for the sucralose-induced elevation of [ATP]c. Both calcium-dependent and -independent mechanisms are involved in the action of sucralose.

  8. 21 CFR 582.7187 - Calcium alginate.

    Science.gov (United States)

    2010-04-01

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

  9. 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...

  10. Modularized study of human calcium signalling pathway

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    When there is an extracellular change, cells get the message either by introduction of calcium ions into ... as it precipitates phosphate, the established energy currency of cells. Prolonged high intracellular calcium ... trigger proteins upon binding with free calcium ion(s) change their confirmation to modulate enzymes and ion ...

  11. 21 CFR 582.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

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

  12. 21 CFR 582.5191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

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

  13. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

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

  14. Mitochondrial Calcium Sparkles Light Up Astrocytes.

    Science.gov (United States)

    MacVicar, Brian A; Ko, Rebecca W Y

    2017-02-27

    Discrete calcium signals in the fine processes of astrocytes are a recent discovery and a new mystery. In a recent issue of Neuron, Agarwal et al. (2017) report that calcium efflux from mitochondria during brief openings of the mitochondrial permeability transition pore (mPTP) contribute to calcium microdomains. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  15. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  16. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  17. ORIGINAL ARTICLES Calcium supplementation to prevent pre ...

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Calcium supplementation to prevent pre-eclampsia - a systematic review. G J Hofmeyr, A Roodt, A N Atallah, L Duley. Background. Calcium supplementation during pregnancy may prevent high blood pressure and preterm labour. Objective. To assess the effects of calcium supplementation.

  18. Calcium Orthophosphate-Based Bioceramics

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2013-09-01

    Full Text Available Various types of grafts have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A bit later, such synthetic biomaterials were called bioceramics. In principle, bioceramics can be prepared from diverse materials but this review is limited to calcium orthophosphate-based formulations only, which possess the specific advantages due to the chemical similarity to mammalian bones and teeth. During the past 40 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the calcium orthophosphate-based implants remain biologically stable once incorporated into the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed and such formulations became an integrated part of the tissue engineering approach. Now calcium orthophosphate scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous and harbor different biomolecules and/or cells. Therefore, current biomedical applications of calcium orthophosphate bioceramics include bone augmentations, artificial bone grafts, maxillofacial reconstruction, spinal fusion, periodontal disease repairs and bone fillers after tumor surgery. Perspective future applications comprise drug delivery and tissue engineering purposes because calcium orthophosphates appear to be promising carriers of growth factors, bioactive peptides and various types of cells.

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

    OpenAIRE

    Huaigang Cheng; Xiaoxi Zhang; Huiping Song

    2014-01-01

    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 calci...

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

    Science.gov (United States)

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

    2013-01-01

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

  1. Apatite Formation from Amorphous Calcium Phosphate and Mixed Amorphous Calcium Phosphate/Amorphous Calcium Carbonate.

    Science.gov (United States)

    Ibsen, Casper J S; Chernyshov, Dmitry; Birkedal, Henrik

    2016-08-22

    Crystallization from amorphous phases is an emerging pathway for making advanced materials. Biology has made use of amorphous precursor phases for eons and used them to produce structures with remarkable properties. Herein, we show how the design of the amorphous phase greatly influences the nanocrystals formed therefrom. We investigate the transformation of mixed amorphous calcium phosphate/amorphous calcium carbonate phases into bone-like nanocrystalline apatite using in situ synchrotron X-ray diffraction and IR spectroscopy. The speciation of phosphate was controlled by pH to favor HPO4 (2-) . In a carbonate free system, the reaction produces anisotropic apatite crystallites with large aspect ratios. The first formed crystallites are highly calcium deficient and hydrogen phosphate rich, consistent with thin octacalcium phosphate (OCP)-like needles. During growth, the crystallites become increasingly stoichiometric, which indicates that the crystallites grow through addition of near-stoichiometric apatite to the OCP-like initial crystals through a process that involves either crystallite fusion/aggregation or Ostwald ripening. The mixed amorphous phases were found to be more stable against phase transformations, hence, the crystallization was inhibited. The resulting crystallites were smaller and less anisotropic. This is rationalized by the idea that a local phosphate-depletion zone formed around the growing crystal until it was surrounded by amorphous calcium carbonate, which stopped the crystallization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Inhibition of release of inflammatory mediators in primary and cultured cells by a Chinese herbal medicine formula for allergic rhinitis

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    McPhee Sarah

    2007-02-01

    Full Text Available Abstract Background We demonstrated that a Chinese herbal formula, which we refer to as RCM-101, developed from a traditional Chinese medicine formula, reduced nasal and non-nasal symptoms of seasonal allergic rhinitis (SAR. The present study in primary and cultured cells was undertaken to investigate the effects of RCM-101 on the production/release of inflammatory mediators known to be involved in SAR. Methods Compound 48/80-induced histamine release was studied in rat peritoneal mast cells. Production of leukotriene B4 induced by the calcium ionophore A23187 was studied in porcine neutrophils using an HPLC assay and lipopolysaccharide-stimulated prostaglandin E2 production was studied in murine macrophage (Raw 264.7 cells by immune-enzyme assay. Expression of cyclooxygenase-1 (COX-1 and cyclooxygenase-2 (COX-2 was determined in Raw 264.7 cells, using western blotting techniques. Results RCM-101 (1–100 μg/mL produced concentration-dependent inhibition of compound 48/80-induced histamine release from rat peritoneal mast cells and of lipopolysaccharide-stimulated prostaglandin E2 release from Raw 264.7 cells. Over the range 1 – 10 μg/mL, it inhibited A23187-induced leukotriene B4 production in porcine neutrophils. In addition, RCM-101 (100 μg/mL inhibited the expression of COX-2 protein but did not affect that of COX-1. Conclusion The findings indicate that RCM-101 inhibits the release and/or synthesis of histamine, leukotriene B4 and prostaglandin E2 in cultured cells. These interactions of RCM-101 with multiple inflammatory mediators are likely to be related to its ability to reduce symptoms of allergic rhinitis.

  3. Structural organization of actin in the sea urchin egg cortex: microvillar elongation in the absence of actin filament bundle formation.

    Science.gov (United States)

    Begg, D A; Rebhun, L I; Hyatt, H

    1982-04-01

    We have investigated the relationship between the formation of actin filament bundles and the elongation of microvilli (MV) after fertilization in sea urchin eggs. In a previous study (1979, J Cell Biol. 83:241-248) we demonstrated that increased pH induced the formation of actin filaments in isolated sea urchin egg cortices with the concomitant elongation of MV. On the basis of these results we suggested that increased cytoplasmic pH after fertilization causes a reorganization of cortical actin, which in turn provides the force for MV elongation. To test this hypothesis, we compared the morphology of microvilli in eggs activated with and without the release of fertilization acid. Activation of eggs in normal sea water with the calcium ionophore A23187 causes the release of fertilization acid and the elongation of MV containing core bundles of actin filaments. Eggs activated with A23187 in NA(+)-free water do not undergo normal fertilization acid release but develop elongated, flaccid MV. These MV contain an irregular network of actin filaments rather than the parallel bundles of filaments found in normal MV. The addition of 40 mM NaCl to these eggs results in the release of H(+) and the concomitant conversion of flaccid MV to erect MV containing typical core bundles of actin filaments. Identical results are obtained when 10 mM NH(4)Cl is substituted for NaCl. The induction of cytoplasmic alkalinization in unactivated eggs with NH(4)Cl does not cause either MV elongation or the formation of actin filament bundles . These results suggest that: (a) the elongation of MV is stimulated by a rise in intracellular free Ca(++) concentration; (b) actin filament bundle formation is triggered by an increase in cytoplasmic pH; and (c) the formation of actin filament bundles is not necessary for MV elongation but is required to provide rigid support for MV.

  4. The effects of intravascular stents on vasomotion in porcine coronary arteries.

    Science.gov (United States)

    Jenkins, J S; Webel, R; Laughlin, M H; Rowland, S M; Yoklavich, M F; Branson, K; Parker, J L; Myers, P R

    1995-09-01

    Intravascular stents are being increasingly utilized in the treatment of atherosclerotic coronary artery disease, however little is known about the effects of stents on coronary vasomotion. The purpose of the present study was to compare the effects of a heparin treated tantalum stent and balloon injury on coronary artery vasorelaxation and vasoconstriction. Male miniswine underwent cardiac catheterization and oversized balloon injury to the right and left circumflex coronary arteries. After two weeks, one artery was either balloon-injured again, or underwent implantation of a stent. Four weeks later, the coronary arteries were prepared for in vitro isometric ring studies. Vasodilator responses to bradykinin and A23187 calcium ionophore were significantly impaired in balloon-injured vessels. The bradykinin and A23187 responses in stented vessels showed significantly less vasorelaxation, compared to both balloon-injured and normal vessels. There were no significant differences between any of the groups in their vasodilator response to nitroprusside. Vasoconstrictor responses to acetylcholine were significantly greater in balloon-injured vessels, compared to normal vessels. Stented vessels, however, showed markedly less vasoconstriction to acetylcholine compared to both balloon-injured and normal vessels. The maximal KCI vasoconstrictor responses in balloon injured vessels and normal controls were not significantly different. However, the maximal KCI responses in stented vessels showed significantly less constriction compared to both balloon injured and normal vessels. In conclusion, the data demonstrated that coronary arteries implanted with a heparin treated tantalum stent were capable of vasomotor activity. Both conventional balloon angioplasty and stents resulted in impaired endothelium-dependent vasorelaxation. Endothelium-independent vasorelaxation, however, was not impaired.(ABSTRACT TRUNCATED AT 250 WORDS)

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

    Science.gov (United States)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

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

  6. The Calcium Wave of Vegetable Cells

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    TD. Geydan

    2007-08-01

    Full Text Available Calcium is an essential nutrient for plants; it is involved in developmental processes and in responses to biotic and abiotic factors. Several signals that modify the calcium concentration in the cytoplasm, endoplasmic reticulum, nucleus and/or plastids have been observed. These changes in the calcium concentration in the cell interior are rapidly returned to basal levels, in the meantime, innumerable and complex signaling cascades. This note exposes the mechanisms of calcium transport through the cell membranes of the entrance of calcium in the plant cells.

  7. Calcium Intake in the Moroccan Elderly

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    Sebbar El-houcine

    2017-08-01

    Full Text Available Introduction: Calcium intakes of elderly people are often below the recommendations which are 1200 mg/day. The advancing age may be accompanied by a loss of capacity to absorb additional calcium in case of deficiency. The aim of our work is to evaluate the calcium intake in the Moroccan elderly. Methods: The version translated into Arabic dialect Fardellone questionnaire is tested on a sample of 159 subjects aged over 60 years. Results: The study population includes 87 women (55%, 72 men (45%. The mean calcium intake was respectively 3078 mg by week (that means 440 mg/day. The assessment of calcium intake showed a deficiency and the average consumption of calcium per day is significantly lower than the recommended daily amount for this population. The comparison of both gender found a deficit higher among women than among men. Conclusion: Evaluation of the calcium intake is an essential tool for better management of metabolic bone diseases.

  8. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    Calcium is one of the several elements that can be found in milk distributed between the micellar and the serum milk phase. Calcium is important from a nutritional point of view, but its contribution to the functional and structural properties of dairy products has only recently been...... acknowledgement. The presence of calcium in a dynamic equilibrium between the serum and the micellar milk phase make the distribution susceptible to certain physicochemical conditions and to technological treatments of milk resulting in fluctuations in pH and temperature and also sensitive to addition of calcium...... salts. The perturbation of calcium equilibria by these factors will affect the final properties of acid, calcium and rennet milk gels. By decreasing the pH from 6.0 to 5.2 (acid gels), the calcium equilibrium was significantly affected by temperature (4, 20, 30, 40 oC), and different combinations...

  9. Exopolysaccharides regulate calcium flow in cariogenic biofilms.

    Science.gov (United States)

    Astasov-Frauenhoffer, Monika; Varenganayil, Muth M; Decho, Alan W; Waltimo, Tuomas; Braissant, Olivier

    2017-01-01

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

  10. Exopolysaccharides regulate calcium flow in cariogenic biofilms.

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    Monika Astasov-Frauenhoffer

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

  11. Calcium precipitate induced aerobic granulation.

    Science.gov (United States)

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Wang, Xingzu; Liu, Xiang

    2015-01-01

    Aerobic granulation is a novel biotechnology for wastewater treatment. This study refined existing aerobic granulation mechanisms as a sequencing process including formation of calcium precipitate under alkaline pH to form inorganic cores, followed by bacterial attachment and growth on these cores to form the exopolysaccharide matrix. Mature granules comprised an inner core and a matrix layer and a rim layer with enriched microbial strains. The inorganic core was a mix of different crystals of calcium and phosphates. Functional strains including Sphingomonas sp., Paracoccus sp. Sinorhizobium americanum strain and Flavobacterium sp. attached onto the cores. These functional strains promote c-di-GMP production and the expression by Psl and Alg genes for exopolysaccharide production to enhance formation of mature granules. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  13. A Closer look at calcium absorption and the benefits and risks of dietary versus supplemental calcium.

    Science.gov (United States)

    Booth, Anna; Camacho, Pauline

    2013-11-01

    To perform a thorough search of the literature on calcium research and specifically address the topic of calcium absorption. PubMed and Ovid were the main engines used for primary literature searches; textbooks, review articles, and book chapters are examples of the other sources used for supplemental information. Regarding calcium absorption, it seems apparent that the absorption efficiency of all calcium salts, regardless of solubility, is fairly equivalent and not significantly less than the absorption efficiency of dietary calcium. However, dietary calcium has been shown to have greater impact in bone building than supplemental calcium. This is likely due to improved absorption with meals and the tendency of people to intake smaller amounts more frequently, which is more ideal for the body's method of absorption. In addition, the cardiovascular risks of excessive calcium intake appear to be more closely related to calcium supplements than dietary calcium; this relationship continues to be controversial in the literature. We conclude that further studies are needed for direct comparison of supplemental and dietary calcium to fully establish if one is superior to the other with regard to improving bone density. We also propose further studies on the cardiovascular risk of long-term increased calcium intake and on physician estimates of patients' daily calcium intake to better pinpoint those patients who require calcium supplementation.

  14. CCN3 and calcium signaling

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    Li Chang Long

    2003-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuerun, E-mail: xuerunli@163.com; Zhang, Yu; Shen, Xiaodong, E-mail: xdshen@njut.edu.cn; Wang, Qianqian; Pan, Zhigang

    2014-01-15

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

  16. Matrine Inhibits Mouse Sperm Function by Reducing Sperm [Ca2+]i and Phospho-ERK1/2

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    Tao Luo

    2015-01-01

    Full Text Available Background: Matrine is a bioactive alkaloid that has a variety of pharmacological effects and is widely used in Chinese medicine. However, its effects on male reproduction are not well known. In this study, we aimed to investigate the in vitro toxicity of matrine on mature mouse sperm. Methods: Mouse cauda epididymal sperm were exposed to matrine (10-200 µM in vitro. The viability, motility, capacitation, acrosome reaction and fertilization ability of the mouse sperm were examined. Furthermore, the intracellular calcium concentration ([Ca2+]i, calcium (Catsper and potassium (Ksper currents, and phosphorylation of extracellular signal regulated kinases 1/2 (p-ERK1/2 of the sperm were analyzed. Results: After exposure to 100 µM or more of matrine, mouse cauda epididymal sperm exhibited a significant reduction in total motility, progressive motility, linear velocity and acrosome reaction rate induced by Ca2+ ionophore A23187. As a result, the fertilization ability of mouse sperm was remarkably decreased by matrine. Our data further demonstrated that matrine significantly reduced sperm [Ca2+]i and [Ca2+]i-related p-ERK1/2; however, both the CatSper and KSper currents, which are thought to interactively regulate Ca2+ influx in sperm, were not affected by matrine. Conclusion: Our findings indicate that matrine inhibits mouse sperm function by reducing sperm [Ca2+]i and suppressing the phosphorylation of ERK1/2.

  17. Use of pharmacological agents to implicate a role for phosphoinositide hydrolysis products in malaria gamete formation.

    Science.gov (United States)

    Ogwan'g, R; Mwangi, J; Gachihi, G; Nwachukwu, A; Roberts, C R; Martin, S K

    1993-11-02

    The kinetics of phosphoinositol 4,5 bisphosphate hydrolysis products in activated Plasmodium falciparum gametocytes suggests a role for inositol trisphosphate [Ins(1,4,5)P3] and diacylglycerol (DAG) in the signal transduction pathway of malaria gametocytes. To investigate further this role, compounds that have an effect on the metabolism and biologic functions of these second messengers were tested in an in vitro system. Gentamycin, 2,3 diphosphoglycerate (2,3 DPG) and magnesium ion (Mg2+), inhibitors of Ins(1,4,5)P3 5' phosphatase, all stimulated gametocytes to exflagellate in suspended animation buffer, pH 7.4, at room temperature. In addition, methylxanthines, caffeine and theobromine, calcium ionophore (A-23187), and external calcium also stimulated exflagellation. In contrast, neomycin, an aminoglycoside that inhibits phospholipase C activity, and heparin, an antagonist of Ins(1,4,5)P3 binding to its receptor, inhibited microgamete formation. Quinine and chloroquine which can inhibit both phospholipase A and C activity also inhibited gametocyte exflagellation. The consistent manner in which these various compounds affect gametocyte activation further implicates phosphoinositol turnover in the signal transduction pathway of falciparum gametocytes.

  18. 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.

  19. Assessment of calcium intake by adolescents

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    Cristiane Franco de Oliveira

    2014-06-01

    Full Text Available OBJECTIVE: To evaluate the daily calcium intake of adolescents in schools from Chapecó, Santa Catarina, Southern Brazil, to check if calcium intake is in accordance with the Dietary Reference Intakes (DRI, and to investigate variables associated with daily calcium intake.METHODS: Cross-sectional study approved by the Institutional Review Board and developed in 2010. Students of the 8th grade completed questionnaires with personal data and questions about the calcium-rich foods intake frequency. In order to compare students with adequate (1300mg or inadequate intake of calcium/day (<1300mg, parametric and nonparametric tests were used.RESULTS: A total of 214 students with a mean age of 14.3±1.0 years were enrolled. The median daily calcium intake was 540mg (interquartile range - IQ: 312-829mg and only 25 students (11.7% had calcium intake within the recommendations of the DRI for age. Soft drink consumption ≥3 times/week was associated with a lower intake of calcium.CONCLUSIONS: Few students ingested adequate levels of calcium for the age group. It is necessary to develop a program to encourage a greater intake of calcium-rich foods in adolescence.

  20. The Risks and Benefits of Calcium Supplementation

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    Chan Soo Shin

    2015-03-01

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

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

    OpenAIRE

    Eder, Anja; Bading, Hilmar

    2007-01-01

    Abstract Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nuc...

  2. Eicosanoid generation and effects on the aggregation of thrombocytes from the rainbow trout, Oncorhynchus mykiss.

    Science.gov (United States)

    Lloyd-Evans, P; Barrow, S E; Hill, D J; Bowden, L A; Rainger, G E; Knight, J; Rowley, A F

    1994-12-08

    Fish blood lacks anucleate platelets but contains a nucleated cell type termed the thrombocyte that is thought to be functionally analogous. Thrombocytes were purified from the peripheral blood of the rainbow trout, Oncorhynchus mykiss, by a two step gradient centrifugation method. Following this procedure, the recovered thrombocytes were 78-86% pure as defined by immunoreactivity to a panel of monoclonal antibodies and were of variable morphology from round to spindle-shaped. Incubation of thrombocyte suspensions with either calcium ionophore, A23187, platelet-activating factor or a thromboxane (TX) mimetic, U-46619, generated a range of eicosanoids derived from arachidonic acid including 12-hydroxyeicosatetraenoic acid (12-HETE), TXB2, prostaglandin (PG) E2, leukotriene (LT) B4 and lipoxin (LX) A4. The equivalent products derived from eicosapentaenoic acid were also formed. Co-incubation of thrombocytes with either erythrocytes or granulocytes/monocytes in the presence of calcium ionophore did not result in the formation of any further new lipoxygenase products. Incubation of isolated thrombocytes in plasma-free conditions with U-46619 (0.03-10 microM) resulted in a rapid, dose-dependent aggregatory response. This effect was markedly augmented in the presence of mammalian fibrinogen (400 micrograms ml-1). Thrombin (0.1-1.3 units ml-1), like U-46619, was also a potent proaggregatory compound for trout thrombocytes. LXA4 and LTB4 had limited aggregatory potential and then only at high concentrations (10 microM), while 12-HETE and PAD had no significant effect at all concentrations tested. These results demonstrate that some of the eicosanoids released during the activation of trout thrombocytes are involved in the aggregatory behaviour of this cell type.

  3. The ability of feline spermatozoa in different epididymal regions to undergo capacitation and acrosome reaction.

    Science.gov (United States)

    Kunkitti, Panisara; Bergqvist, Ann-Sofi; Sjunnesson, Ylva; Axnér, Eva

    2015-10-01

    The sperm maturation process that occurs in the epididymis is a necessary process for spermatozoa to acquire motility and the ability to undergo capacitation, which is an important key for fertilization. The aim of this study was to evaluate the ability of feline spermatozoa from different regions of the epididymis to undergo capacitation and acrosome reaction. Experiment I: epididymal spermatozoa from caput, corpus and cauda regions were placed in phosphate buffered saline (control medium) and in vitro fertilization medium (capacitating conditions). Sperm motility, motility patterns, plasma membrane integrity and tyrosine phosphorylation were evaluated at time 0 and 60min after incubation. Experiment II: spermatozoa were treated with 2μM of calcium ionophore (A23187) to induce the acrosome reaction and acrosome reaction was evaluated. The results showed a significant effect of region with a higher percentage of tyrosine phosphorylation in spermatozoa from the cauda than in the caput or corpus regions (P=0.0061; P=0.0088). Spermatozoa from corpus and cauda showed higher values in the majority of the measured motility parameters than spermatozoa from the caput (Pepididymal regions can undergo the acrosome reaction in vitro in response to induction by calcium ionophore with no difference between regions (P>0.05). Spermatozoa from all epididymal regions were able to undergo capacitation. Higher percentage of tyrosine phosphorylation in spermatozoa from the cauda reflect that they more easily underwent capacitation compared to spermatozoa from caput and corpus which required more time of incubation for capacitation. In conclusion feline epididymal spermatozoa from all regions can undergo capacitation and acrosome reaction in vitro and do not require incubation under capacitating conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Calcium gluconate supplementation is effective to balance calcium homeostasis in patients with gastrectomy.

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    Krause, M; Keller, J; Beil, B; van Driel, I; Zustin, J; Barvencik, F; Schinke, T; Amling, M

    2015-03-01

    We demonstrate histological evidence for hyperparathyroidism in patients with gastrectomy. This is, at least in part, explained by impaired calcium absorption, resulting in mineralization defects and secondary hyperparathyroidism. Additionally, we demonstrate improved bone mineralization in patients with gastrectomy after gluconate therapy and showed the effectiveness of calcium gluconate over carbonate to balance impaired calcium hemostasis in mice. Gastrectomy and hypochlorhydria due to long-term proton pump inhibitor therapy are associated with increased fracture risk because of intestinal calcium malabsorption. Hence, our objectives were to histologically investigate bone metabolism in patients with gastrectomy and to analyze the impact of calcium gluconate supplementation on skeletal integrity in the setting of impaired gastric acidification. Undecalcified bone biopsies of 26 gastrectomized individuals were histologically analyzed. In the clinical setting, we retrospectively identified 5 gastrectomized patients with sufficient vitamin D level, who were additionally supplemented with calcium gluconate and had a real bone mineral density (aBMD) follow-up assessments. A mouse model of achlorhydria (ATP4b-/-) was used to compare the effect of calcium gluconate and calcium carbonate supplementation on bone metabolism. Biopsies from gastrectomized individuals showed significantly increased osteoid, osteoclast, and osteoblast indices and fibroosteoclasia (p < 0.05) as well as impaired calcium distribution in mineralized bone matrix compared to healthy controls. Five gastrectomized patients with sufficient vitamin D level demonstrated a significant increase in aBMD after a treatment with calcium gluconate alone for at least 6 months (p < 0.05). Calcium gluconate was superior to calcium carbonate in maintaining calcium metabolism in a mouse model of achlorhydria. Gastrectomy is associated with severe osteomalacia, marrow fibrosis, and impaired calcium distribution

  5. Influence of calcium sources on microbially induced calcium carbonate precipitation by Bacillus sp. CR2.

    Science.gov (United States)

    Achal, Varenyam; Pan, Xiangliang

    2014-05-01

    Stimulation of microbially induced calcium carbonate precipitation (MICCP) is likely to be influenced by calcium sources. In order to study such influences, we performed MICCP using Bacillus sp. CR2 in nutrient broth containing urea, supplemented with different calcium sources (calcium chloride, calcium oxide, calcium acetate and calcium nitrate). The experiment lasted 7 days, during which bacterial growth, urease activity, calcite production and pH were measured. Our results showed that calcium chloride is the better calcium source for MICCP process, since it provides higher urease activity and more calcite production. The influences of calcium sources on MICCP were further studied using Fourier transform-infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. These analyses confirmed that the precipitate formed was CaCO3 and composed of predominantly calcite crystals with a little amount of aragonite and vaterite crystals. The maximum yield of calcite precipitation was achievable with calcium chloride followed by calcium nitrate as a calcium source. The results of present study may be applicable to media preparation during efficient MICCP process.

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

    Directory of Open Access Journals (Sweden)

    Bading Hilmar

    2007-07-01

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

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

    Science.gov (United States)

    Eder, Anja; Bading, Hilmar

    2007-01-01

    Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nucleus from activity-induced cytoplasmic calcium transients in some cell types. Results Using laser-assisted uncaging of caged calcium compounds in defined sub-cellular domains, we show here that the nuclear compartment border does not represent a barrier for calcium signals in hippocampal neurons. Although passive diffusion of molecules between the cytosol and the nucleoplasm may be modulated through changes in conformational state of the nuclear pore complex, we found no evidence for a gating mechanism for calcium movement across the nuclear border. Conclusion Thus, the nuclear envelope does not spatially restrict calcium transients to the somatic cytosol but allows calcium signals to freely enter the cell nucleus to trigger genomic events. PMID:17663775

  8. 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 (Ca2+). 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.

  9. Calcium excretion in feces of ungulates.

    Science.gov (United States)

    Schryver, H F; Foose, T J; Williams, J; Hintz, H F

    1983-01-01

    1. Fecal excretion of calcium was examined in 122 individual ungulates representing 7 species of Equidae, 3 species of Tapiridae, 3 species of Rhinocerotidae, 2 species of Elephantidae, 2 species of Hippopotamidae, 12 species of Bovidae, 2 species of Cervidae, 3 species of Camellidae and 1 species of Giraffidae. 2. Animals were fed timothy hay, a low calcium diet or alfalfa hay, a high calcium diet. 3. In a few cases oat straw or prairie hay was used instead of timothy hay. 4. Samples of feces were obtained from individuals daily for 4 days following a 20 day dietary equilibration period. 5. Feces of equids, tapirs, rhinoceros and elephants had a lower calcium concentration and a lower Ca/P ratio than feces of ruminants when the animals were fed diets of equivalent calcium content. 6. The findings suggest that the non-ruminant ungulate equids, tapirs, rhinoceros and elephants absorb a larger proportion of dietary calcium than ruminants do.

  10. Binding of calcium and carbonate to polyacrylates.

    Science.gov (United States)

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

    2009-05-21

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

  11. WAYS TO CORRECT CALCIUM DEFFICIT AMONG CHILDREN

    Directory of Open Access Journals (Sweden)

    N.I. Taibulatov

    2007-01-01

    Full Text Available The article is dedicated to the urgent issue of the pediatrics — calcium deficit among children. The authors provide modern data on the scheme of the normal calcium exchange in the human body. They also review the main diseases related to the disorders of the pho sphorocalcic metabolism, requiring prompt prevention and treatment by calcium based medications. The researchers stress the diseases of the musculoskeletal system, as insufficient calcium, phosphorus and vitamins supply of the child's body chiefly effects the state of the skeletal and muscular tissue. They give recommendations how to use the vitamin and mineral complex to correct calcium deficit.Key words: calcium deficit, diseases of the musculoskeletal system, vitamin and mineral complex, children.

  12. Altered calcium signaling in cancer cells.

    Science.gov (United States)

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

    2015-10-01

    It is the nature of the calcium signal, as determined by the coordinated activity of a suite of calcium channels, pumps, exchangers and binding proteins that ultimately guides a cell's fate. Deregulation of the calcium signal is often deleterious and has been linked to each of the 'cancer hallmarks'. Despite this, we do not yet have a full understanding of the remodeling of the calcium signal associated with cancer. Such an understanding could aid in guiding the development of therapies specifically targeting altered calcium signaling in cancer cells during tumorigenic progression. Findings from some of the studies that have assessed the remodeling of the calcium signal associated with tumorigenesis and/or processes important in invasion and metastasis are presented in this review. The potential of new methodologies is also discussed. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Calcium dobesilate: pharmacology and future approaches.

    Science.gov (United States)

    Tejerina, T; Ruiz, E

    1998-09-01

    1. Calcium dobesilate (2,5-dihydroxybenzene sulfonate) is a drug commonly used in the treatment of diabetic retinopathy and chronic venous insufficiency. 2. The pharmacology of calcium dobesilate reveals its ability to decrease capillary permeability, as well as platelet aggregation and blood viscosity. 3. Furthermore, recent data show that calcium dobesilate increases endothelium-dependent relaxation owing to an increase in nitric oxide synthesis.

  14. Presynaptic calcium dynamics of learning neurons

    OpenAIRE

    Meyer-Hermann, Michael; Erler, Frido; Soff, Gerhard

    2002-01-01

    We present a new model for the dynamics of the presynaptic intracellular calcium concentration in neurons evoked by various stimulation protocols. The aim of the model is twofold: We want to discuss the calcium transients during and after specific stimulation protocols as they are used to induce long-term-depression and long-term-potentiation. In addition we would like to provide a general tool which allows the comparison of different calcium experiments. This may help to draw conclusions on ...

  15. Protein-Mediated Precipitation of Calcium Carbonate

    OpenAIRE

    Izabela Polowczyk; Anna Bastrzyk; Marta Fiedot

    2016-01-01

    Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquire...

  16. Mechanical Properties of a Calcium Dietary Supplement, Calcium Fumarate Trihydrate.

    Science.gov (United States)

    Sun, Shijing; Henke, Sebastian; Wharmby, Michael T; Yeung, Hamish H-M; Li, Wei; Cheetham, Anthony K

    2015-12-07

    The mechanical properties of calcium fumarate trihydrate, a 1D coordination polymer considered for use as a calcium source for food and beverage enrichment, have been determined via nanoindentation and high-pressure X-ray diffraction with single crystals. The nanoindentation studies reveal that the elastic modulus (16.7-33.4 GPa, depending on crystallographic orientation), hardness (1.05-1.36 GPa), yield stress (0.70-0.90 GPa), and creep behavior (0.8-5.8 nm/s) can be rationalized in view of the anisotropic crystal structure; factors include the directionality of the inorganic Ca-O-Ca chain and hydrogen bonding, as well as the orientation of the fumarate ligands. High-pressure single-crystal X-ray diffraction studies show a bulk modulus of ∼ 20 GPa, which is indicative of elastic recovery intermediate between small molecule drug crystals and inorganic pharmaceutical ingredients. The combined use of nanoindentation and high-pressure X-ray diffraction techniques provides a complementary experimental approach for probing the critical mechanical properties related to tableting of these dietary supplements.

  17. Calcium dependence of inactivation of calcium release from the sarcoplasmic reticulum in skeletal muscle fibers.

    Science.gov (United States)

    Simon, B J; Klein, M G; Schneider, M F

    1991-03-01

    The steady-state calcium dependence of inactivation of calcium release from the sarcoplasmic reticulum was studied in voltage-clamped, cut segments of frog skeletal muscle fibers containing two calcium indicators, fura-2 and anti-pyrylazo III (AP III). Fura-2 fluorescence was used to monitor resting calcium and relatively small calcium transients during small depolarizations. AP III absorbance signals were used to monitor larger calcium transients during larger depolarizations. The rate of release (Rrel) of calcium from the sarcoplasmic reticulum was calculated from the calcium transients. The equilibrium calcium dependence of inactivation of calcium release was determined using 200-ms prepulses of various amplitudes to elevate [Ca2+] to various steady levels. Each prepulse was followed by a constant test pulse. The suppression of peak Rrel during the test pulse provided a measure of the extent of inactivation of release at the end of the prepulse. The [Ca2+] dependence of inactivation indicated that binding of more than one calcium ion was required to inactivate each release channel. Half-maximal inactivation was produced at a [Ca2+] of approximately 0.3 microM. Variation of the prepulse duration and amplitude showed that the suppression of peak release was consistent with calcium-dependent inactivation of calcium release but not with calcium depletion. The same calcium dependence of inactivation was obtained using different amplitude test pulses to determine the degree of inactivation. Prepulses that produced near maximal inactivation of release during the following test pulse produced no suppression of intramembrane charge movement during the test pulse, indicating that inactivation occurred at a step beyond the voltage sensor for calcium release. Three alternative set of properties that were assumed for the rapidly equilibrating calcium-binding sites intrinsic to the fibers gave somewhat different Rrel records, but gave very similar calcium dependence of

  18. Protein-Mediated Precipitation of Calcium Carbonate.

    Science.gov (United States)

    Polowczyk, Izabela; Bastrzyk, Anna; Fiedot, Marta

    2016-11-22

    Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure's growth in the investigated system. In this study, samples of CaCO₃ particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to 'stack-like' structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO₃ formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein.

  19. Diuretics and disorders of calcium homeostasis.

    Science.gov (United States)

    Grieff, Marvin; Bushinsky, David A

    2011-11-01

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

  20. [ZINK IS ACTIVATOR OF ENTERAL CALCIUM METABOLISM].

    Science.gov (United States)

    Polyakova, E P; Ksenofontov, D A; Revyakin, A O; Ivanov, A A

    2015-01-01

    Experiments on goats and rabbits showed that zinc supplement to the diet leads to calcium concentration rise in muscle, bone and blood of animals. However, this rise was not adequate to increase in.zinc consumption. The bulk of alimentary zinc stayed in soluble fraction, dense endogen fraction and infusoria fraction of digesta and stimulated calcium release from food particles, it's accumulation in digesta fractions and calcium utilization on the whole. Authors estimate animal digesta as homeostatic, spatial organized, endogenic formation in which zinc and calcium are functionally dependent through enteral mucosa.

  1. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

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

    1981-01-01

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

  2. 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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  4. Plasma membrane calcium pump and sodium-calcium exchanger in maintenance and control of calcium concentrations in platelets.

    Science.gov (United States)

    Juska, Alfonsas

    2010-01-29

    The purpose of this research was to elucidate the activity of the mechanisms responsible for control of cytosolic calcium concentration in platelets by modeling the time-course of the concentration changing in response to discharge of the intracellular stores or store-operated calcium entry (SOCE). The parameters estimated as a result of model fitting to experimental data are related to physiological or pathological state of the cells. It has been shown that: (a) the time-course is determined by the passive calcium fluxes and activities of the corresponding mechanisms; (b) the decline in the concentration (after its rise) develops due to activity of plasma membrane calcium ATPase (PMCA) both in the case of discharge of the stores of platelets contained in calcium-free medium and in the case of SOCE; (c) impulsive extrusion of calcium in response to its sudden influx, presumably, is the main function of PMCA; (d) the function of sodium-calcium exchanger (NCX) is to extrude calcium excess by permanent counteracting its influx. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  5. Pseudogout and Calcium Pyrophosphate Disease

    Directory of Open Access Journals (Sweden)

    Andrew Williamson

    2017-01-01

    Full Text Available History of present illness: A 53-year-old male presented with worsening right knee pain and swelling over the past 48 hours. He denied recent trauma to the knee, history of IV drug use, and recent illness. He had no history of diabetes, immunodeficiency, chronic steroids, rheumatologic disease, or knee replacement. He described the pain as sharp, non-radiating, and worse with movement. He was unable to walk due to pain. Significant findings: Radiographs of the knee showed multiple radio-dense lines paralleling the articular surface (see red arrows consistent with calcium pyrophosphate crystal deposition within the joint often seen in calcium pyrophosphate disease (CPPD also known as pseudogout. Discussion: Patients commonly present to the emergency department with non-traumatic joint pain. Arthrocentesis is an important diagnostic tool to evaluate for septic arthritis, gout, or pseudogout. Arthrocentesis can demonstrate crystals or abnormal cell count, gram stain, and culture.[1] In the evaluation of joint pain, plain films are usually obtained to evaluate for fracture, dislocation, effusion, or secondary signs of infection. In this case the classic x-ray supported the diagnosis of CPPD.2 The patient was found to have positively birefringent rhomboid shaped crystals consistent with pseudogout on arthrocentesis. Gram stain and culture were both negative. The patient was discharged with NSAIDs and had significant improvement in symptoms upon follow up with primary care physician in 3 days.

  6. Paclitaxel induces apoptosis in breast cancer cells through different calcium--regulating mechanisms depending on external calcium conditions.

    Science.gov (United States)

    Pan, Zhi; Avila, Andrew; Gollahon, Lauren

    2014-02-17

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

  7. Spatiotemporal intracellular calcium dynamics during cardiac alternans

    Science.gov (United States)

    Restrepo, Juan G.; Karma, Alain

    2009-09-01

    Cellular calcium transient alternans are beat-to-beat alternations in the peak cytosolic calcium concentration exhibited by cardiac cells during rapid electrical stimulation or under pathological conditions. Calcium transient alternans promote action potential duration alternans, which have been linked to the onset of life-threatening ventricular arrhythmias. Here we use a recently developed physiologically detailed mathematical model of ventricular myocytes to investigate both stochastic and deterministic aspects of intracellular calcium dynamics during alternans. The model combines a spatially distributed description of intracellular calcium cycling, where a large number of calcium release units are spatially distributed throughout the cell, with a full set of ionic membrane currents. The results demonstrate that ion channel stochasticity at the level of single calcium release units can influence the whole-cell alternans dynamics by causing phase reversals over many beats during fixed frequency pacing close to the alternans bifurcation. They also demonstrate the existence of a wide range of dynamical states. Depending on the sign and magnitude of calcium-voltage coupling, calcium alternans can be spatially synchronized or desynchronized, in or out of phase with action potential duration alternans, and the node separating out-of-phase regions of calcium alternans can be expelled from or trapped inside the cell. This range of states is found to be larger than previously anticipated by including a robust global attractor where calcium alternans can be spatially synchronized but out of phase with action potential duration alternans. The results are explained by a combined theoretical analysis of alternans stability and node motion using general iterative maps of the beat-to-beat dynamics and amplitude equations.

  8. Cell swelling activates K+ and Cl- channels as well as nonselective, stretch-activated cation channels in ehrlich ascites tumor cells

    DEFF Research Database (Denmark)

    Christensen, Ove; Hoffmann, Else Kay

    1992-01-01

    external K+ is estimated at about 7 pS. A K+ channel with similar properties can be activated in the cellattached mode by addition of Ca2+ plus ionophore A23187. The channel is also activated by cell swelling, within 1 min following hypotonic exposure. No evidence was found of channel activation...... in the cell-attached mode could be activated by addition of Ca2+ plus ionophore A23187. The channel is also activated by hypotonic exposure with a single-channel conductance at 7 pS (or less) and with a time delay at about 1 min. The number of open channels during RVD is estimated at 80 per cell. Two other...

  9. Calcium Blood Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/calciumbloodtest.html Calcium Blood Test To use the sharing features on this page, please enable JavaScript. What is a Calcium Blood Test? A calcium blood test measures the ...

  10. The mechanism of epipodophyllotoxin-induced thymocyte apoptosis: possible role of a novel Ca(2+)-independent protein kinase.

    Science.gov (United States)

    Ye, X; Georgoff, I; Fleisher, S; Coffman, F D; Cohen, S; Fresa, K L

    1993-10-15

    the Ca2+ ionophore A23187. Moreover, while strong increases in intracellular Ca2+ were observed in thymocytes treated with A23187, we failed to detect increases in intracellular Ca2+ in cells induced to apoptose with either VM-26 or dexamethasone within the first 2 hr of culture. These results suggest that in mouse thymocytes there are at least two intracellular pathways leading to apoptosis: one, utilized by glucocorticoid and the epipodophyllotoxins, that proceeds in the absence of detectable increases in intracellular Ca2+ and possibly requires a novel Ca(2+)-independent PKC-like enzyme and another, utilized by Ca2+ ionophores, that is at least partially dependent on increased intracellular Ca2+.

  11. 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

  12. Calcium and M'yocardial Infarction

    African Journals Online (AJOL)

    1974-03-16

    Mar 16, 1974 ... Urinary excretion of calcium tended to be even lower in these .... 16 March 1974. S.A. MEDICAL JOURNAL. 525. 150. 50. Fig. 5. Urine calcium in myocardial infarction (means and standard error relative to age). AGE OF PATIENT .... Plasma proteins and blood urea were also measured in. 10 consecutive ...

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

    Directory of Open Access Journals (Sweden)

    R. Mänd

    2000-10-01

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

  14. 21 CFR 182.8223 - Calcium pyrophosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pyrophosphate. 182.8223 Section 182.8223 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8223 Calcium...

  15. 21 CFR 182.8217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.8217 Section 182.8217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium...

  16. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

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

  17. Role of calcium in selenium cataract.

    Science.gov (United States)

    Shearer, T R; David, L L

    The purpose of this research was to test the role of certain minerals in the formation of cataract caused by an overdose of selenium. Several pieces of information indicated that lenticular calcium may play an important role in selenite cataractogenesis: 1) Lens calcium concentrations in selenite treated rats were increased more than 5-fold, and the increase in lens calcium was localized in the nucleus. 2) Lens calcium concentrations were elevated at least one full day before actual formation of nuclear cataract, but serum calcium levels were not changed. 3) In older rats not susceptible to selenite cataract, lens calcium was not significantly increased. 4) No evidence was found for a generalized disruption in lens permeability, since no major changes in lens water, sodium, and potassium levels were observed, and 5) when levels of calcium observed in selenite cataract were added to solutions of soluble proteins from rat lenses, light scattering was increased. Selenium-overdose cataracts may provide an important model for studies on the role of calcium in cataractogenesis.

  18. Adding calcium improves lithium ferrite core

    Science.gov (United States)

    Lessoff, H.

    1969-01-01

    Adding calcium increases uniformity of grain growth over a wide range of sintering temperatures and reduces porosity within the grain. Ferrite cores containing calcium have square hysteresis loops and high curie temperatures, making them useful in coincident current memories of digital electronic computers.

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  20. Comparison of Serum Calcium and Magnesium Between ...

    African Journals Online (AJOL)

    The present study compared serum calcium and magnesium in forty preeclamptic (cases) and forty normotensive (control) pregnant women matched for age, parity, and socioeconomic status. Serum calcium and magnesium levels were measured using atomic absorption spectrophotometer. Statistical analysis was done ...

  1. Dairy Dilemma: Are You Getting Enough Calcium?

    Science.gov (United States)

    ... body also needs vitamin D to absorb calcium. Nutrition surveys have shown that most people in the U.S. aren’t getting the calcium they need. If you’re avoiding milk and dairy ... taking nutritional supplements and choosing reduced-lactose or non-dairy ...

  2. CALCIUM AND THE PREVENTION OF COLON CANCER

    NARCIS (Netherlands)

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

    1991-01-01

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

  3. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    salts. The perturbation of calcium equilibria by these factors will affect the final properties of acid, calcium and rennet milk gels. By decreasing the pH from 6.0 to 5.2 (acid gels), the calcium equilibrium was significantly affected by temperature (4, 20, 30, 40 oC), and different combinations...... of temperature and pH may result in different final structure properties in dairy products such as cheese. A significant amount of calcium remained in the micelles between pH 4.8 and 4.6, this can contribute to the final strength of acid milk gels, such as in yogurt or in cream cheeses. After the gelation point......, a sudden solubilization of micellar calcium was observed at 50 oC and 60 oC, which revealed an interesting role of calcium during acidification at elevated temperatures. After enrichment of milk with calcium D-lactobionate, the added calcium was distributed between the micellar and serum milk phase at pH 6...

  4. Bespuiten met calcium kan neusrot voorkomen

    NARCIS (Netherlands)

    Blom-Zandstra, Greet; Marcelis, L.F.M.

    2000-01-01

    Oorzaak van neusrot bij paprika is een calciumtekort in de vrucht. Een bespuiting met calcium vlak na de bloei heeft een zeer gunstig effect. In bijgaande tabel gegevens over het effect van spuiten met calcium op het optreden van neusrot bij paprika

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

    Directory of Open Access Journals (Sweden)

    Sandra Tavares da Silva

    2013-06-01

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

  6. Store-operated calcium entry is essential for glial calcium signalling in CNS white matter.

    Science.gov (United States)

    Papanikolaou, M; Lewis, A; Butt, A M

    2017-02-28

    'Calcium signalling' is the ubiquitous response of glial cells to multiple extracellular stimuli. The primary mechanism of glial calcium signalling is by release of calcium from intracellular stores of the endoplasmic reticulum (ER). Replenishment of ER Ca(2+) stores relies on store-operated calcium entry (SOCE). However, despite the importance of calcium signalling in glial cells, little is known about their mechanisms of SOCE. Here, we investigated SOCE in glia of the mouse optic nerve, a typical CNS white matter tract that comprises bundles of myelinated axons and the oligodendrocytes and astrocytes that support them. Using quantitative RT-PCR, we identified Orai1 channels, both Stim1 and Stim2, and the transient receptor potential M3 channel (TRPM3) as the primary channels for SOCE in the optic nerve, and their expression in both astrocytes and oligodendrocytes was demonstrated by immunolabelling of optic nerve sections and cultures. The functional importance of SOCE was demonstrated by fluo-4 calcium imaging on isolated intact optic nerves and optic nerve cultures. Removal of extracellular calcium ([Ca(2+)]o) resulted in a marked depletion of glial cytosolic calcium ([Ca(2+)]i), which recovered rapidly on restoration of [Ca(2+)]o via SOCE. 2-aminoethoxydiphenylborane (2APB) significantly decreased SOCE and severely attenuated ATP-mediated calcium signalling. The results provide evidence that Orai/Stim and TRPM3 are important components of the 'calcium toolkit' that underpins SOCE and the sustainability of calcium signalling in white matter glia.

  7. Plant Calcium Content: Ready to Remodel

    Directory of Open Access Journals (Sweden)

    Mary Lou Guerinot

    2012-08-01

    Full Text Available By identifying the relationship between calcium location in the plant cell and nutrient bioavailability, the plant characteristics leading to maximal calcium absorption by humans can be identified. Knowledge of plant cellular and molecular targets controlling calcium location in plants is emerging. These insights should allow for better strategies for increasing the nutritional content of foods. In particular, the use of preparation-free elemental imaging technologies such as synchrotron X-ray fluorescence (SXRF microscopy in plant biology may allow researchers to understand the relationship between subcellular location and nutrient bioavailability. These approaches may lead to better strategies for altering the location of calcium within the plant to maximize its absorption from fruits and vegetables. These modified foods could be part of a diet for children and adults identified as at-risk for low calcium intake or absorption with the ultimate goal of decreasing the incidence and severity of inadequate bone mineralization.

  8. Endoplasmic reticulum calcium stores in dendritic spines.

    Science.gov (United States)

    Segal, Menahem; Korkotian, Eduard

    2014-01-01

    Despite decades of research, the role of calcium stores in dendritic spines structure, function and plasticity is still debated. The reasons for this may have to do with the multitude of overlapping calcium handling machineries in the neuron, including stores, voltage and ligand gated channels, pumps and transporters. Also, different cells in the brain are endowed with calcium stores that are activated by different receptor types, and their differential compartmentalization in dendrites, spines and presynaptic terminals complicates their analysis. In the present review we address several key issues, including the role of calcium stores in synaptic plasticity, their role during development, in stress and in neurodegenerative diseases. Apparently, there is increasing evidence for a crucial role of calcium stores, especially of the ryanodine species, in synaptic plasticity and neuronal survival.

  9. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani

    2013-01-01

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

  10. Calcium phosphate: a substitute for aluminum adjuvants?

    Science.gov (United States)

    Masson, Jean-Daniel; Thibaudon, Michel; Bélec, Laurent; Crépeaux, Guillemette

    2017-03-01

    Calcium phosphate was used as an adjuvant in France in diphtheria, tetanus, pertussis and poliomyelitis vaccines. It was later completely substituted by alum salts in the late 80's, but it still remains as an approved adjuvant for the World Health Organization for human vaccination. Area covered: Thus, calcium phosphate is now considered as one of the substances that could replace alum salts in vaccines. The aim of this paper is to draw a review of existing data on calcium phosphate as an adjuvant in order to bring out the strengths and weaknesses for its use on a large scale. Expert commentary: Calcium phosphate is a compound naturally present in the organism, safe and already used in human vaccination. Beyond comparisons with the other adjuvants, calcium phosphate represents a good candidate to replace or to complete alum salts as a vaccine adjuvant.

  11. Plant Calcium Content: Ready to Remodel

    Science.gov (United States)

    Yang, Jian; Punshon, Tracy; Guerinot, Mary Lou; Hirschi, Kendal D.

    2012-01-01

    By identifying the relationship between calcium location in the plant cell and nutrient bioavailability, the plant characteristics leading to maximal calcium absorption by humans can be identified. Knowledge of plant cellular and molecular targets controlling calcium location in plants is emerging. These insights should allow for better strategies for increasing the nutritional content of foods. In particular, the use of preparation-free elemental imaging technologies such as synchrotron X-ray fluorescence (SXRF) microscopy in plant biology may allow researchers to understand the relationship between subcellular location and nutrient bioavailability. These approaches may lead to better strategies for altering the location of calcium within the plant to maximize its absorption from fruits and vegetables. These modified foods could be part of a diet for children and adults identified as at-risk for low calcium intake or absorption with the ultimate goal of decreasing the incidence and severity of inadequate bone mineralization. PMID:23016135

  12. The calcium and vitamin D controversy

    DEFF Research Database (Denmark)

    Abrahamsen, Bo

    2017-01-01

    or subanalyses while maintaining balancing. Though large clinical RCTs currently evaluate the effects of higher vitamin D doses (equivalent to 50–83 μg/d) there is no current research effort regarding the calcium controversy. In the absence of such studies it is not possible to provide clinicians with evidence......Areas of the world where vitamin D levels are low for months of the year and intakes of calcium are high have a high prevalence of osteoporosis and cardiovascular disease. This suggests a public health message of avoiding calcium supplements and increasing vitamin D intake. No message could be more...... welcome as vitamin D can be given as a bolus while calcium must be taken daily and may be poorly tolerated. This approach is based on no evidence from intervention studies. Randomized controlled trials (RCTs) suggest that vitamin D given with calcium elicits a small reduction in fracture risk and deaths...

  13. Expert review on coronary calcium

    Directory of Open Access Journals (Sweden)

    Matthew J Budoff

    2008-04-01

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

  14. Strontium Substitution for Calcium in Lithogenesis

    Science.gov (United States)

    Blaschko, Sarah D.; Chi, Thomas; Miller, Joe; Flechner, Lawrence; Fakra, Sirine; Kapahi, Pankaj; Kahn, Arnold; Stoller, Marshall L.

    2013-01-01

    Purpose Strontium has chemical similarity to calcium, which enables the replacement of calcium by strontium in biomineralization processes. Incorporating strontium into human bone and teeth has been studied extensively but little research has been performed of the incorporation of strontium into urinary calculi. We used synchrotron based x-ray fluorescence and x-ray absorption techniques to examine the presence of strontium in different types of human kidney stones. Materials and Methods Multiple unique human stone samples were obtained via consecutive percutaneous nephrolithotomies/ureteroscopies. A portion of each stone was sent for standard laboratory analysis and a portion was retained for x-ray fluorescence and x-ray absorption measurements. X-ray fluorescence and x-ray absorption measurements determined the presence, spatial distribution and speciation of strontium in each stone sample. Results Traditional kidney stone analyses identified calcium oxalate, calcium phosphate, uric acid and cystine stones. X-ray fluorescence measurements identified strontium in all stone types except pure cystine. X-ray fluorescence elemental mapping of the samples revealed co-localization of calcium and strontium. X-ray absorption measurements of the calcium phosphate stone showed strontium predominately present as strontium apatite. Conclusions Advanced x-ray fluorescence imaging identified strontium in all calcium based stones, present as strontium apatite. This finding may be critical since apatite is thought to be the initial nidus for calcium stone formation. Strontium is not identified by standard laboratory stone analyses. Its substitution for calcium can be reliably identified in stones from multiple calcium based stone formers, which may offer opportunities to gain insight into early events in lithogenesis. PMID:23260568

  15. A comparison of total calcium, corrected calcium, and ionized calcium concentrations as indicators of calcium homeostasis among hypoalbuminemic dogs requiring intensive care.

    Science.gov (United States)

    Sharp, Claire R; Kerl, Marie E; Mann, F A

    2009-12-01

    (1) To evaluate whether total calcium (tCa) correlates with ionized calcium (iCa) in hypoalbuminemic dogs; (2) to evaluate whether calcium adjusted for albumin (Alb), or total protein (TP), or both accurately predict iCa concentrations and hence can be used to monitor calcium homeostasis in critically ill hypoalbuminemic dogs; and (3) to evaluate factors associated with any potential discrepancy in calcium classification between corrected total and ionized values. Prospective observational clinical study. Small animal intensive care unit in a veterinary medical teaching hospital. Twenty-eight client-owned dogs with hypoalbuminemia. None. iCa was determined using ion-specific electrode methodology, on heparinized plasma. The tCa concentration was adjusted for Alb and TP using published equations. In total 29% (8/28) of the hypoalbuminemic, critically ill dogs in this study were hypocalcemic at intensive care unit admission, as determined by iCa measurement. Corrected calcium values failed to accurately classify calcium status in 67.9% and 64.3% of cases, according to whether the Alb-adjusted or TP-adjusted values, respectively, were used. The sensitivity and specificity of the tCa to evaluate hypocalcemia was 100% and 47%, respectively. The sensitivity and specificity of the correction formulae were 37.5% and 79% for the Alb-adjusted values and 37.5% and 74% for TP-adjusted values. tCa overestimated the presence of hypocalcemia and underestimated the presence of normocalcemia, while corrected calcium values overestimated the presence of normocalcemia and underestimated the presence of hypocalcemia. Calcium homeostasis in hypoalbuminemic critically ill dogs should be evaluated by iCa concentrations rather than tCa or calcium adjusted for Alb or TP. Given that tCa has 100% sensitivity for detecting hypocalcemia in this population it is recommended that all hypoalbuminemic and critically ill patients with low tCa should be evaluated with an iCa measurement.

  16. Tuning local calcium availability: cell-type-specific immobile calcium buffer capacity in hippocampal neurons.

    Science.gov (United States)

    Matthews, Elizabeth A; Schoch, Susanne; Dietrich, Dirk

    2013-09-04

    It has remained difficult to ascribe a specific functional role to immobile or fixed intracellular calcium buffers in central neurons because the amount of these buffers is unknown. Here, we explicitly isolated the fixed buffer fraction by prolonged whole-cell patch-clamp dialysis and quantified its buffering capacity in murine hippocampal slices using confocal calcium imaging and the "added-buffer" approach. In dentate granule cells, the calcium binding ratio (κ) after complete washout of calbindin D28k (Cb), κfixed, displayed a substantial value of ∼100. In contrast, in CA1 oriens lacunosum moleculare (OLM) interneurons, which do not contain any known calcium-binding protein(s), κfixed amounted to only ∼30. Based on these values, a theoretical analysis of dendritic spread of calcium after local entry showed that fixed buffers, in the absence of mobile species, decrease intracellular calcium mobility 100- and 30-fold in granule cells and OLM cells, respectively, and thereby strongly slow calcium signals. Although the large κfixed alone strongly delays the spread of calcium in granule cells, this value optimizes the benefits of additionally expressing the mobile calcium binding protein Cb. With such high κfixed, Cb effectively increases the propagation velocity to levels seen in OLM cells and, contrary to expectation, does not affect the peak calcium concentration close to the source but sharpens the spatial and temporal calcium gradients. The data suggest that the amount of fixed buffers determines the temporal availability of calcium for calcium-binding partners and plays a pivotal role in setting the repertoire of cellular calcium signaling regimens.

  17. 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.

  18. Non-calcium desulphurisation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Qian Zhu [IEA Clean Coal Centre, London (United Kingdom)

    2010-06-15

    Flue gas desulphurisation (FGD) is traditionally based on limestone/lime sorbent. The majority of the installed FGD systems worldwide use limestone or lime as sorbent. However, technologies are rapidly evolving that allow desulphurisation in regions where there are limited resources of lime or limestone. These technologies provide alternatives to limestone/lime scrubbers for efficient and cost effective control of SO{sub 2} emissions from coal combustion. This report reviews the existing and emerging non-calcium based FGD processes as well as FGD technologies currently under development that apply new concepts and different approaches. It looks at the fundamentals and features of these processes, the recent technical advances and their applications in coal-fired power plants. The capital and operating costs of the processes are evaluated where information available. 66 refs., 15 figs., 10 tabs.

  19. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  20. 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. © 2010 International Life Sciences Institute.

  1. Calcium phosphate scaffold from biogenic calcium carbonate by fast ambient condition reactions

    Science.gov (United States)

    Dutta, Abhishek; Fermani, Simona; Arjun Tekalur, Srinivasan; Vanderberg, Abigail; Falini, Giuseppe

    2011-12-01

    Calcium phosphate biogenic materials are biocompatible and promote bioactivity and osteoconductivity, which implies their natural affinity and tendency to bond directly to bones subsequently replacing the host bone after implantation owing to its biodegradability. Calcium hydrogen phosphate dihydrate, CaHPO 4·2H 2O, is known to be a nucleation precursor, in aqueous solutions, for apatitic calcium phosphates and, hence, a potential starting material for bone substitutes. Numerous approaches, via hydrothermal and ambient synthetic routes, have been used to produce calcium phosphate from biogenic calcium carbonate, taking advantage of the peculiar architecture and composition of the latter. In this article, the lamellar region of the cuttlefish bone ( Sepia officinalis) was used as a framework for the organized deposition of calcium phosphate crystals, at ambient conditions via a fast procedure involving an amorphous calcium carbonate intermediate, and ending with a conversion to calcium phosphate and a fixation procedure, thereby resulting in direct conversion of biogenic calcium carbonate into calcium phosphates at ambient conditions from the scale of months to hours.

  2. Transgenic plants with increased calcium stores

    Science.gov (United States)

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

    2004-01-01

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

  3. In vitro antioxidant properties of calcium dobesilate.

    Science.gov (United States)

    Brunet, J; Farine, J C; Garay, R P; Hannaert, P

    1998-01-01

    Calcium dobesilate, a vascular protective agent, was tested in vitro for its scavenging action against oxygen free radicals. Calcium dobesilate was as potent as rutin to scavenge hydroxyl radicals (IC50 = 1.1 vs 0.7 microM, respectively). It was also able to scavenge superoxide radicals, but with 23 times less potency than rutin (IC50 = 682 vs 30 microM, respectively). Calcium dobesilate significantly reduced platelet activating factor (PAF)-induced chemiluminescence in human PMN cells and lipid peroxidation by oxygen free radicals in human erythrocyte membranes, although these actions required calcium dobesilate concentrations > or = 50 microM. Finally, in cultured bovine aortic endothelial cells, magnesium dobesilate reduced the increase in cytosolic free calcium induced by hydrogen peroxide and inhibited phenazine methosulfate-induced cell potassium loss. In conclusion, calcium dobesilate was effective in scavenging hydroxyl radicals in vitro, at therapeutically relevant concentrations. Conversely, higher concentrations of the compound were required to scavenge superoxide radicals or to protect the cells against the deleterious effects of intracellular reactive oxygen species. Further studies in vivo are required to determine if these antioxidant properties of calcium dobesilate can play a role in its vascular protective mechanisms.

  4. Intracellular sphingosine releases calcium from lysosomes

    Science.gov (United States)

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

    2015-01-01

    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC. DOI: http://dx.doi.org/10.7554/eLife.10616.001 PMID:26613410

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

    Science.gov (United States)

    Yu, Ji-Kuen; Pan, Huichin; Huang, Shing-Moo; Huang, Nan-Lan; Yao, Chung-Chin; Hsiao, Kuang-Ming; Wu, Chew-Wun

    2013-01-01

    Our aim was to investigate the calcium content of different gallstone compositions and the pathogenic mechanisms of calcium carbonate gallstones. Between August 2001 and July 2007, gallstones from 481 patients, including 68 calcium carbonate gallstones, were analyzed for total calcium content. Gallbladder bile samples from 33 cases and six controls were analyzed for pH, carbonate anion level, free-ionized calcium concentration and saturation index for calcium carbonate. Total calcium content averaged 75.6 %, 11.8 %, and 4.2 % for calcium carbonate, calcium bilirubinate and cholesterol gallstones. In 29.4 % of patients, chronic and/or intermittent cystic duct obstructions were caused by polypoid lesions in the neck region and 70.6 % were caused by stones. A total of 82 % of patients had chronic low-grade inflammation of the gallbladder wall and 18.0 % had acute inflammatory exacerbations. In the bile, we found the mean pH, mean carbonate anion, free-ionized calcium concentrations, and mean saturation index for calcium carbonate to be elevated in comparison to controls. From our study, we found chronic and/or intermittent cystic duct obstructions and low-grade GB wall inflammation lead to GB epithelium hydrogen secretion dysfunction. Increased calcium ion efflux into the GB lumen combined with increased carbonate anion presence increases SI_CaCO(3) from 1 to 22.4. Thus, in an alkaline milieu with pH 7.8, calcium carbonate begins to aggregate and precipitate. Copyright © 2012. Published by Elsevier B.V.

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

    Directory of Open Access Journals (Sweden)

    Nishiura J.L.

    2002-01-01

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

  7. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture*

    Science.gov (United States)

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

    2015-01-01

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

  8. Protein-Mediated Precipitation of Calcium Carbonate

    Directory of Open Access Journals (Sweden)

    Izabela Polowczyk

    2016-11-01

    Full Text Available Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FTIR measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure’s growth in the investigated system. In this study, samples of CaCO3 particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to ‘stack-like’ structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO3 formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein.

  9. Protein-Mediated Precipitation of Calcium Carbonate

    Science.gov (United States)

    Polowczyk, Izabela; Bastrzyk, Anna; Fiedot, Marta

    2016-01-01

    Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) measurements. In addition, the turbidity of the reaction solution was acquired to monitor the kinetics of the calcium carbonate structure’s growth in the investigated system. In this study, samples of CaCO3 particles obtained with individual proteins, such as ovalbumin, lysozyme, and a mixture of the proteins, were characterized and compared with a control sample, i.e., synthesized without proteins. The obtained data indicated that the addition of ovalbumin to the reaction changed the morphology of crystals from rhombohedral to ‘stack-like’ structures. Lysozyme, however, did not affect the morphology of calcium carbonate, yet the presence of the protein mixture led to the creation of more complex composites in which the calcium carbonate crystals were constructed in protein matrices formed by the ovalbumin-lysozyme interaction. It was also observed that in the protein mixture, ovalbumin has a major influence on the CaCO3 formation through a strong interaction with calcium ions, which leads to the coalescence and creation of a steric barrier reducing particle growth. The authors proposed a mechanism of calcium carbonate grain growth in the presence of both proteins, taking into account the interaction of calcium ions with the protein. PMID:28774065

  10. Murine and human SDF2L1 is an endoplasmic reticulum stress-inducible gene and encodes a new member of the Pmt/rt protein family.

    Science.gov (United States)

    Fukuda, S; Sumii, M; Masuda, Y; Takahashi, M; Koike, N; Teishima, J; Yasumoto, H; Itamoto, T; Asahara, T; Dohi, K; Kamiya, K

    2001-01-12

    We isolated murine and human cDNAs for SDF2L1 (stromal cell-derived factor 2-like1) and characterized the genomic structures. Northern blot analysis of the gene expression in various tissues revealed that both murine Sdf2l1 and human SDF2L1 genes are expressed ubiquitously, with particularly high expression in the testis. The SDF2L1 protein has an endoplasmic reticulum (ER)-retention-like motif, HDEL, at the carboxy (C)-terminus. Interestingly, SDF2L1 protein also shows significant similarity to the central hydrophilic part of protein O-mannosyltransferase (Pmt) proteins of Saccharomyces cerevisiae, the human homologues of Pmt (POMT1 and POMT2) and Drosophila melanogaster rotated abdomen (rt) protein. In a murine hepatocellular carcinoma cell line, Sdf2l1 was strongly induced by tunicamycin and a calcium ionophore, A23187, and weakly induced by heat stress but was not induced by cycloheximide. In conclusion, SDF2L1 protein is a new member of Pmt/rt protein family and Sdf2l1 is a new ER stress-inducible gene. Copyright 2001 Academic Press.

  11. Human sperm chromosome analysis after subzonal sperm insemination of hamster oocytes

    Energy Technology Data Exchange (ETDEWEB)

    Cozzi, J. [Medical School of Grenoble (France)

    1994-09-01

    Sperm microinjection techniques, subzonal sperm insemination (SUZI) and intracytoplasmic sperm injection (ICSI), have achieved a wide spread clinical application for the treatment of male infertility. To date, only one study has focused on sperm karyotypes after microinjection. Martin et al. reported a very high incidence of abnormal human sperm complements after ICSI into hamster oocytes. In the present study, are reported the first human sperm karyotypes after SUZI of hamster oocytes. Spermatozoa from two control donors were treated by calcium ionophore A23187 and injected under the zona of hamster eggs. The microinjected eggs were then cultured for cytogenetic analysis of the pronuclei. Out of 47 analyzed sperm chromosome metaphases, 5 (10.6%) were abnormal, 4 (8.5%) were hypohaploid and 1 (2.1%) had a structural abnormality. The sex ratio was not significantly different from the expected 1:1 ratio. Rates of chromosomal abnormalities in microinjected spermatozoa were similar to those observed in spermatozoa inseminated with zona free eggs, suggesting that SUZI procedure per se does not increase sperm chromosomal abnormalities.

  12. In vitro and in vivo protein phosphorylation in Avena sativa L. coleoptiles: effects of Ca2+, calmodulin antagonists, and auxin

    Science.gov (United States)

    Veluthambi, K.; Poovaiah, B. W.

    1986-01-01

    In vitro and in vivo protein phosphorylations in oat (Avena sativa L.) coleoptile segments were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and by two-dimensional gel electrophoresis. In vitro phosphorylation of several polypeptides was distinctly promoted at 1 to 15 micromolar free Ca2+ concentrations. Ca2(+)-stimulated phosphorylation was markedly reduced by trifluoperazine, chlorpromazine, and naphthalene sulfonamide (W7). Two polypeptides were phosphorylated both under in vitro and in vivo conditions, but the patterns of phosphorylation of several other polypeptides were different under the two conditions indicating that the in vivo phosphorylation pattern of proteins is not truly reflected by in vitro phosphorylation studies. Trifluoperazine, W7, or ethylene glycol-bis-(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) + calcium ionophore A23187 treatments resulted in reduced levels of in vivo protein phosphorylation of both control and auxin-treated coleoptile segments. Analysis by two-dimensional electrophoresis following in vivo phosphorylation revealed auxin-dependent changes of certain polypeptides. A general inhibition of phosphorylation by calmodulin antagonists suggested that both control and auxin-treated coleoptiles exhibited Ca2+, and calmodulin-dependent protein phosphorylation in vivo.

  13. Expression, Localization of SUMO-1, and Analyses of Potential SUMOylated Proteins in Bubalus bubalis Spermatozoa

    Directory of Open Access Journals (Sweden)

    Rahim Dad Brohi

    2017-06-01

    Full Text Available Mature spermatozoa have highly condensed DNA that is essentially silent both transcriptionally and translationally. Therefore, post translational modifications are very important for regulating sperm motility, morphology, and for male fertility in general. Protein sumoylation was recently demonstrated in human and rodent spermatozoa, with potential consequences for sperm motility and DNA integrity. We examined the expression and localization of small ubiquitin-related modifier-1 (SUMO-1 in the sperm of water buffalo (Bubalus bubalis using immunofluorescence analysis. We confirmed the expression of SUMO-1 in the acrosome. We further found that SUMO-1 was lost if the acrosome reaction was induced by calcium ionophore A23187. Proteins modified or conjugated by SUMO-1 in water buffalo sperm were pulled down and analyzed by mass spectrometry. Sixty proteins were identified, including proteins important for sperm morphology and motility, such as relaxin receptors and cytoskeletal proteins, including tubulin chains, actins, and dyneins. Forty-six proteins were predicted as potential sumoylation targets. The expression of SUMO-1 in the acrosome region of water buffalo sperm and the identification of potentially SUMOylated proteins important for sperm function implicates sumoylation as a crucial PTM related to sperm function.

  14. Comparative studies on the antiallergic effects of kampo medicines used for the therapy of respiratory diseases.

    Science.gov (United States)

    Nyunt, A K; Takeuchi, Y; Yokomuro, K; Miyanaga, Y

    1995-04-01

    Eight kinds of kampo medicines mainly used for the treatment of asthma and other respiratory diseases, whose comparative effects were still unproven, were selected for comparison of their antiallergic activity in the present study. 1) In an experiment on 48-hr PCA reaction in rats passively sensitized with anti egg albumin IgE antisera, inhibitory effects were observed in those groups orally administered with the tested kampo medicines. Among the drugs tested, TJ-19 showed a potent inhibitory activity as effective as that of tranilast (TL). 2) In the study of extraction method, the effects of kampo drugs varied widely according to the extraction method by which they were prepared. This suggests that the routine methods for preparing these extracts should be reconsidered to achieve the optimal efficacy. 3) In the study of histamine release from rat peritoneal cells stimulated with compound 48/80, TJ-55, TJ-19 and TL exerted a strong inhibition, but TJ-119, TJ-29 and TJ-96 had a weak inhibition. 4) TJ-96, TJ-19 and TL exerted a strong inhibitory effect on LTC, release from rat peritoneal mast cells induced by calcium (Ca) ionophore A23187, but TJ-95, TJ-55 and TJ-119 exerted only a weak inhibition. To sum up of the results, any of these kampo medicines have unique pharmacological action and antiallergic effects. Besides, the method for extraction affects the efficacy of kampo medicine in vitro.

  15. The Ameliorative Effect of Sophoricoside on Mast Cell-Mediated Allergic Inflammation in Vivo and in Vitro

    Directory of Open Access Journals (Sweden)

    Jae-Young Um

    2013-05-01

    Full Text Available Sophoricoside exhibits numerous pharmacological effects, including anti- inflammatory and anti-cancer actions, yet the exact mechanism that accounts for the anti-allergic effects of sophoricoside is not completely understood. The aim of the present study was to elucidate whether and how sophoricoside modulates the mast cell-mediated allergic inflammation in vitro and in vivo. We investigated the pharmacological effects of sophoricoside on both compound 48/80 or histamine-induced scratching behaviors and 2,4-dinitrochlorobenzene (DNCB-induced atopic dermatitis in mice. Additionally, to find a possible explanation for the anti-inflammatory effects of sophoricoside, we evaluated the effects of sophoricoside on the production of histamine and inflammatory cytokines and activation of nuclear factor-κB (NF-κB and caspase-1 in phorbol 12-myristate 13-acetate plus calcium ionophore A23187 (PMACI-stimulated human mast cells (HMC-1. The finding of this study demonstrated that sophoricoside reduced compound 48/80 or histamine-induced scratching behaviors and DNCB-induced atopic dermatitis in mice. Additionally, sophoricoside inhibited the production of inflammatory cytokines as well as the activation of NF-κB and caspase-1 in stimulated HMC-1. Collectively, the findings of this study provide us with novel insights into the pharmacological actions of sophoricoside as a potential molecule for use in the treatment of allergic inflammation diseases.

  16. Lactadherin inhibits secretory phospholipase A2 activity on pre-apoptotic leukemia cells.

    Directory of Open Access Journals (Sweden)

    Steffen Nyegaard

    Full Text Available Secretory phospholipase A2 (sPLA2 is a critical component of insect and snake venoms and is secreted by mammalian leukocytes during inflammation. Elevated secretory PLA2 concentrations are associated with autoimmune diseases and septic shock. Many sPLA2's do not bind to plasma membranes of quiescent cells but bind and digest phospholipids on the membranes of stimulated or apoptotic cells. The capacity of these phospholipases to digest membranes of stimulated or apoptotic cells correlates to the exposure of phosphatidylserine. In the present study, the ability of the phosphatidyl-L-serine-binding protein, lactadherin to inhibit phospholipase enzyme activity has been assessed. Inhibition of human secretory phospholipase A2-V on phospholipid vesicles exceeded 90%, whereas inhibition of Naja mossambica sPLA2 plateaued at 50-60%. Lactadherin inhibited 45% of activity of Naja mossambica sPLA2 and >70% of human secretory phospholipase A2-V on the membranes of human NB4 leukemia cells treated with calcium ionophore A23187. The data indicate that lactadherin may decrease inflammation by inhibiting sPLA2.

  17. Theanine is a candidate amino acid for pharmacological stabilization of mast cells.

    Science.gov (United States)

    Kim, N H; Jeong, H J; Kim, H M

    2012-05-01

    The increasing occurrences of allergic disorders may be attributed to exposure to environmental factors that contribute to the pathogenesis of allergy. The health benefits of green tea have been widely reported but are largely unsubstantiated. Theanine is the major amino acid present in green tea. In this study, we investigated the role of theanine in both IgE- and non- IgE-induced allergic response. Theanine inhibited compound 48/80-induced systemic anaphylactic shock and ear swelling responses. IgE-mediated passive cutaneous anaphylaxis was inhibited by the oral administration or pharmaceutical acupuncture of theanine. Histamine release from mast cells was decreased with the treatment of theanine. Theanine also repressed phorbol 12-myristate 13-acetate and calcium ionophore A23187-induced TNF-α, IL-1β, IL-6, and IL-8 secretion by suppressing NF-κB activation. Furthermore, theanine suppressed the activation of caspase-1 and the expression of receptor interacting protein-2. The current study demonstrates for the first time that theanine might possess mast cell-stabilizing capabilities.

  18. Expression of the rat prothymosin alpha gene during T-lymphocyte proliferation and liver regeneration.

    Science.gov (United States)

    Bustelo, X R; Otero, A; Gómez-Márquez, J; Freire, M

    1991-01-25

    Prothymosin alpha (ProT alpha) is a widely distributed acidic protein whose function has been related to cell proliferation. We have analyzed the expression of the rat ProT alpha gene in several proliferative systems: concanavalin A (ConA)/interleukin-2-stimulated thymocytes, ConA-stimulated splenic T-lymphocytes, and hepatocytes proliferating during liver regeneration. In these systems, ProT alpha mRNA was detected in all stages of the cell cycle, with maximal increments (2-4-fold) at the beginning of the S phase. By contrast, the mRNAs for proliferating cell nuclear antigen/cyclin and histone H3, two cell-cycle-regulated proteins, were hardly detected in resting cells but increased notably at the G1/S boundary and in the S phase, respectively. Treatment of T-cells with the calcium ionophore A23187 increased ProT alpha mRNA levels 2.5-fold, whereas phorbol 12-myristate 13-acetate, a protein kinase C activator, had no effect on ProT alpha gene expression. Incubation of ConA-stimulated T-cells with hydroxyurea, a DNA synthesis inhibitor, did not decrease the levels of ProT alpha mRNA, indicating that its expression is independent of DNA synthesis. These findings suggest that ProT alpha is required throughout all the stages of the cell cycle, resembling a constitutively expressed gene rather than one strictly involved in cell proliferation.

  19. Polyamines are present in mast cell secretory granules and are important for granule homeostasis.

    Science.gov (United States)

    García-Faroldi, Gianni; Rodríguez, Carlos E; Urdiales, José L; Pérez-Pomares, José M; Dávila, José C; Pejler, Gunnar; Sánchez-Jiménez, Francisca; Fajardo, Ignacio

    2010-11-30

    Mast cell secretory granules accommodate a large number of components, many of which interact with highly sulfated serglycin proteoglycan (PG) present within the granules. Polyamines (putrescine, spermidine and spermine) are absolutely required for the survival of the vast majority of living cells. Given the reported ability of polyamines to interact with PGs, we investigated the possibility that polyamines may be components of mast cell secretory granules. Spermidine was released by mouse bone marrow derived mast cells (BMMCs) after degranulation induced by IgE/anti-IgE or calcium ionophore A23187. Additionally, both spermidine and spermine were detected in isolated mouse mast cell granules. Further, depletion of polyamines by culturing BMMCs with α-difluoromethylornithine (DFMO) caused aberrant secretory granule ultrastructure, impaired histamine storage, reduced serotonin levels and increased β-hexosaminidase content. A proteomic approach revealed that DFMO-induced polyamine depletion caused an alteration in the levels of a number of proteins, many of which are connected either with the regulated exocytosis or with the endocytic system. Taken together, our results show evidence that polyamines are present in mast cell secretory granules and, furthermore, indicate an essential role of these polycations during the biogenesis and homeostasis of these organelles.

  20. Polyamines are present in mast cell secretory granules and are important for granule homeostasis.

    Directory of Open Access Journals (Sweden)

    Gianni García-Faroldi

    2010-11-01

    Full Text Available Mast cell secretory granules accommodate a large number of components, many of which interact with highly sulfated serglycin proteoglycan (PG present within the granules. Polyamines (putrescine, spermidine and spermine are absolutely required for the survival of the vast majority of living cells. Given the reported ability of polyamines to interact with PGs, we investigated the possibility that polyamines may be components of mast cell secretory granules.Spermidine was released by mouse bone marrow derived mast cells (BMMCs after degranulation induced by IgE/anti-IgE or calcium ionophore A23187. Additionally, both spermidine and spermine were detected in isolated mouse mast cell granules. Further, depletion of polyamines by culturing BMMCs with α-difluoromethylornithine (DFMO caused aberrant secretory granule ultrastructure, impaired histamine storage, reduced serotonin levels and increased β-hexosaminidase content. A proteomic approach revealed that DFMO-induced polyamine depletion caused an alteration in the levels of a number of proteins, many of which are connected either with the regulated exocytosis or with the endocytic system.Taken together, our results show evidence that polyamines are present in mast cell secretory granules and, furthermore, indicate an essential role of these polycations during the biogenesis and homeostasis of these organelles.