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Sample records for replacing potassium calcium

  1. Partial replacement of NaCl can be achieved with potassium, magnesium and calcium salts in brown bread.

    Science.gov (United States)

    Charlton, Karen E; MacGregor, Elizabeth; Vorster, Nonnie H; Levitt, Naomi S; Steyn, Krisela

    2007-11-01

    To develop a reduced-sodium bread in which salt (NaCl) is partially replaced with potassium, magnesium and calcium salts. Experimental bread was compared against standard brown bread, after a drop test (to assess whether bread quality deteriorates with abuse) and after the usual baking practices for baking properties (volume, crust colour, crumb colour and cell structure), sensory properties and nutritional composition. Plant production feasibility was evaluated in an industrial plant. Breads produced there were subjected to sensory evaluation using triangulation tests in a panel of 122 consumers. Twenty-four samples of both standard and experimental bread were laboratory-analysed for sodium, potassium, magnesium and calcium content. A 32.3% reduced-sodium brown bread was developed that was acceptable in terms of baking qualities, appearance, texture and taste. The potassium, magnesium and calcium contents of the bread were increased by 55.2%, 69.0%, and 34.8%, respectively.

  2. Contracture Coupling of Slow Striated Muscle in Non-Ionic Solutions and Replacement of Calcium, Sodium, and Potassium

    Science.gov (United States)

    Irwin, Richard L.; Hein, Manfred M.

    1964-01-01

    The development of contracture related to changes of ionic environment (ionic contracture coupling) has been studied in the slowly responding fibers of frog skeletal muscle. When deprived of external ions for 30 minutes by use of solutions of sucrose, mannitol, or glucose, the slow skeletal muscle fibers, but not the fast, develop pronounced and easily reversible contractures. Partial replacement of the non-ionic substance with calcium or sodium reduces the development of the contractures but replacement by potassium does not. The concentration of calcium necessary to prevent contracture induced by a non-ionic solution is greater than that needed to maintain relaxation in ionic solutions. To suppress the non-ionic-induced contractures to the same extent as does calcium requires several fold higher concentrations of sodium. Two types of ionic contracture coupling occur in slow type striated muscle fibers: (a) a calcium deprivation type which develops maximally at full physiological concentration of external sodium, shows a flow rate dependency for the calcium-depriving fluid, and is lessened when the sodium concentration is decreased by replacement with sucrose; (b) a sodium deprivation type which occurs maximally without external sodium, is lessened by increasing the sodium concentration, and has no flow rate dependency for ion deprivation. Both types of contracture are largely prevented by the presence of sufficient calcium. There thus seem to be calcium- and sodium-linked processes at work in the ionic contracture coupling of slow striated muscle. PMID:14127603

  3. Calcium, magnesium, and potassium in food

    Science.gov (United States)

    The biochemical and physiological functions and consequences of deficient intakes, which show the nutritional importance of calcium, magnesium and potassium for humans, are reviewed. The dietary recommendations and food sources for these essential mineral elements for humans are presented. Factors t...

  4. Adsorption of Potassium and Calcium Ions by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    LIHONG-YAN; JIGUO-LIANG

    1992-01-01

    Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.

  5. Both barium and calcium activate neuronal potassium currents.

    OpenAIRE

    Ribera, A B; Spitzer, N C

    1987-01-01

    Amphibian spinal neurons in culture possess both rapidly inactivating and sustained calcium-dependent potassium current components, similar to those described for other cells. Divalent cation-dependent whole-cell outward currents were isolated by subtracting the voltage-dependent potassium currents recorded from Xenopus laevis neurons in the presence of impermeant cadmium (100-500 microM) from the currents produced without cadmium but in the presence of permeant divalent cations (50-100 micro...

  6. Both barium and calcium activate neuronal potassium currents

    Energy Technology Data Exchange (ETDEWEB)

    Ribera, A.B.; Spitzer, N.C.

    1987-09-01

    Amphibian spinal neurons in culture possess both rapidly inactivating and sustained calcium-dependent potassium current components, similar to those described for other cells. Divalent cation-dependent whole-cell outward currents were isolated by subtracting the voltage-dependent potassium currents recorded from Xenopus laevis neurons in the presence of impermeant cadmium from the currents produced without cadmium but in the presence of permeant divalent cations. These concentrations of permeant ions were low enough to avoid contamination by macroscopic inward currents through calcium channels. Calcium-dependent potassium currents were reduced by 1 ..mu..M tetraethylammonium. These currents can also be activated by barium or strontium. Barium as well as calcium activated outward currents in young neurons (6-8 hr) and in relatively mature neurons (19-26 hr in vitro). However, barium influx appeared to suppress the sustained voltage-dependent potassium current in most cells. Barium also activated at least one class of potassium channels observed in excised membrane patches, whole blocking others. The blocking action may have masked and hindered detection of the stimulatory action of barium in other systems.

  7. Potassium citrate decreases urine calcium excretion in patients with hypocitraturic calcium oxalate nephrolithiasis.

    Science.gov (United States)

    Song, Yan; Hernandez, Natalia; Shoag, Jonathan; Goldfarb, David S; Eisner, Brian H

    2016-04-01

    Two previous studies (nephrolithiasis. The hypothesized mechanisms are (1) a decrease in bone turnover due to systemic alkalinization by the medications; (2) binding of calcium by citrate in the gastrointestinal tract; (3) direct effects on TRPV5 activity in the distal tubule. We performed a retrospective review of patients on potassium citrate therapy to evaluate the effects of this medication on urinary calcium excretion. A retrospective review was performed of a metabolic stone database at a tertiary care academic hospital. Patients were identified with a history of calcium oxalate nephrolithiasis and hypocitraturia who were on potassium citrate therapy for a minimum of 3 months. 24-h urine composition was assessed prior to the initiation of potassium citrate therapy and after 3 months of therapy. Patients received 30-60 mEq potassium citrate by mouth daily. Inclusion criterion was a change in urine potassium of 20 mEq/day or greater, which suggests compliance with potassium citrate therapy. Paired t test was used to compare therapeutic effect. Twenty-two patients were evaluated. Mean age was 58.8 years (SD 14.0), mean BMI was 29.6 kg/m(2) (SD 5.9), and gender prevalence was 36.4% female:63.6% male. Mean pre-treatment 24-h urine values were as follows: citrate 280.0 mg/day, potassium 58.7 mEq/day, calcium 216.0 mg/day, pH 5.87. Potassium citrate therapy was associated with statistically significant changes in each of these parameters-citrate increased to 548.4 mg/day (p < 0.0001), potassium increased to 94.1 mEq/day (p < 0.0001), calcium decreased to 156.5 mg/day (p = 0.04), pH increased to 6.47 (p = 0.001). Urine sodium excretion was not different pre- and post-therapy (175 mEq/day pre-therapy versus 201 mEq/day post-therapy, p = NS). Urinary calcium excretion decreased by a mean of 60 mg/day on potassium citrate therapy-a nearly 30 % decrease in urine calcium excretion. These data lend support to the hypothesis that alkali therapy reduces urine calcium

  8. Calcium-activated potassium conductance noise in snail neurons.

    Science.gov (United States)

    Westerfield, M; Lux, H D

    1982-11-01

    Current fluctuations were measured in small, 3-6 micrometers-diameter patches of soma membrane in bursting neurons of the snail, Helix pomatia. The fluctuations dramatically increased in magnitude with depolarization of the membrane potential under voltage clamp conditions. Two components of conductance noise were identified in the power spectra calculated from the membrane currents. One component had a corner frequency which increased with depolarization. This component was blocked by intracellular injection of TEA and was relatively insensitive to extracellular calcium levels (as long as the total number of effective divalent cations remained constant). It was identified as fluctuations of the voltage-dependent component of delayed outward current. The second component of conductance noise had a corner frequency which decreased with depolarization. It was relatively unaffected by TEA injection and was reversibly blocked by substitution of extracellular calcium with magnesium, cobalt, or nickel. This second component of noise was identified as fluctuations of the calcium-dependent potassium current. The results suggest that the two components of delayed outward current are conducted through physically distinct channels.

  9. Calcium-dependent potassium current in barnacle photoreceptor.

    Science.gov (United States)

    Bolsover, S R

    1981-12-01

    When barnacle lateral eye photoreceptors are depolarized to membrane potentials of 0 to +50 mV in the dark, the plot of outward current through the cell membrane against time has two distinct maxima. The first maximum occurs 5-10 ms after the depolarization began. The current then decays to a minimum at approximately 500 ms after the onset of depolarization, and then increases to a second maximum 4-6 s after the depolarization began. If depolarization is maintained, the current again decays to reach a steady value approximately 1 min after depolarization began. The increase in current to the maximum at 4-6s from the minimum at approximately 500 ms is termed the "late current." It is maximum for depolarizations to around +25 mV and is reduced in amplitude at more positive potentials. It is not observed when the membrane is depolarized to potentials more positive than +60 mV. The late current is inhibited by external cobaltous ion and external tetraethylammonium ion, and shows a requirement for external calcium ion. When the calcium-sequestering agent EGTA is injected, the late current is abolished. Illumination of a cell under voltage clamp reduces the amplitude of the late current recorded subsequently in the dark. On the basis of the voltage dependence and pharmacology of the late current, it is proposed that the current is a calcium-dependent potassium current.

  10. Evidence for a distinct light-induced calcium-dependent potassium current in Hermissenda crassicornis.

    Science.gov (United States)

    Blackwell, K T

    2000-01-01

    A model of phototransduction is developed as a first step toward a model for investigating the critical interaction of light and turbulence stimuli within the type B photoreceptor of Hermissenda crassicronis. The model includes equations describing phototransduction, release of calcium from intracellular stores, and other calcium regulatory mechanisms, as well as equations describing ligand-gating of a rhabdomeric sodium current. The model is used to determine the sources of calcium in the soma, whether calcium or IP3 is a plausible ligand of the light-induced sodium current, and whether the light-induced potassium current is equivalent to the calcium-dependent potassium current activated by light-induced calcium release. Simulations show that the early light-induced calcium elevation is due to influx through voltage-dependent channels, whereas the later calcium elevation is due to release from intracellular stores. Simulations suggest that the ligand of the fast, light-induced sodium current is IP3 but that there is a smaller, prolonged component of the light-induced sodium current that is activated by calcium. In the model, the calcium-dependent potassium current, located in the soma, is activated only slightly by light-induced calcium elevation, leading to the prediction that a calcium-dependent potassium current, active at resting potential, is located in the rhabdomere and is responsible for the light-induced potassium current.

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

    Directory of Open Access Journals (Sweden)

    Anton Hermann

    2015-08-01

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

  12. Study Of Calcium And Potassium Different Nature Strength Gel Kappa-Carrageenan

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    Петро Васильович Гурський

    2015-07-01

    Full Text Available The influence of certain organic and mineral salts of potassium and calcium for strength gel kappa-carrageenan. The influence of the mass concentration of individual calcium for strength gels with different content kappa-carrageenan. Grounded mass concentration of some calcium salts for use in the composition of the jelly for sweet and savory dishes based on kappa-carrageenan

  13. Equilibrium studies of sodium-ammonium potassium-ammonium, and calcium-ammonium exchanges on clinoptilolite zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Jama, M.A.; Yuecel, H. (Middle East Technical Univ., Ankara (Turkey))

    1989-12-01

    Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv/dm{sup 3} and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full replacement of the cation by the ammonium ion is observed, which conflicts with some earlier work on clinoptilolite. Despite the observed partial exchange levels, clinoptilolite shows a very high preference for ammonium ion over sodium and calcium but not over potassium. Thermodynamic values for the exchanges were calculated and compared with data in the literature. Both the selectivity and thermodynamic affinity sequence, in agreement with previous work reported in the literature, are K{sup +} > NH{sub 4}{sup +} > Na{sup +} > Ca{sup 2+}.

  14. Mechanism of Action of Novel Glibenclamide Derivatives on Potassium and Calcium Channels for Insulin Secretion.

    Science.gov (United States)

    Frederico, Marisa Jádson Silva; Castro, Allisson Jhonatan Gomes; Menegaz, Danusa; De Bernardis Murat, Cahuê; Mendes, Camila Pires; Mascarello, Alessandra; Nunes, Ricardo José; Silva, Fátima Regina Mena Barreto

    2016-06-14

    Glibenclamide is widely used and remains a cornerstone and an effective antihyperglycemic drug. After the casual discovery of its hypoglycemic potential, this compound was introduced for diabetes treatment. However, the long-term side effects reveal that glibenclamide should be replaced by new molecules able to maintain the health of β-cells, protecting them from hyperstimulation/hyperexcitability, hyperinsulinemia, functional failure and cell death. The aim of this review was to highlight the main mechanism of action of glibenclamide and the influence of its derivatives, such as acyl-hydrazones, sulfonamides and sulfonylthioureas on β-cells potassium and calcium channels for insulin secretion as well as the contribution of these new compounds to restore glucose homeostasis. Furthermore, the role of glibenclamide-based novel structures that promise less excitability of β-cell in a long-term treatment with effectiveness and safety for diabetes therapy was discussed.

  15. Fatal Dysrhythmia Following Potassium Replacement for Hypokalemic Periodic Paralysis

    Directory of Open Access Journals (Sweden)

    Ahmed, Imdad

    2010-02-01

    Full Text Available We present a case of fatal rebound hyperkalemia in a patient with thyrotoxic periodic paralysis (TPP treated with potassium supplementation. Although TPP is a rare hyperthyroidism-related endocrine disorder seen predominantly in men of Asian origin, the diagnosis should be considered in patients of non-Asian origins presenting with hypokalemia, muscle weakness or acute paralysis. The condition may present as a life threatening emergency and unfamiliarity with the disease could result in a fatal outcome. Immediate therapy with potassium chloride supplementation may foster a rapid recovery of muscle strength and prevent cardiac arrhythmias secondary to hypokalemia, but with a risk of rebound hyperkalemia. [West J Emerg Med. 2010; 11(1:57-59.

  16. Whole-cell recordings of calcium and potassium currents in acutely isolated smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Qing Cai; Zhong-Liang Zhu; Xiao-Li Fan

    2006-01-01

    AIM: To record calcium and potassium currents in acutely isolated smooth muscle cells of mesenteric arterial branches in rats.METHODS: Smooth muscle cells were freshly isolated by collagenase digest and mechanical trituration with polished pipettes. Patch clamp technique in whole-cell mode was employed to record calcium and potassium currents.RESULTS: The procedure dissociated smooth muscle cells without impairing the electrophysiological characteristics of the cells. The voltage-gated Ca2+ and potassium currents were successfully recorded using whole-cell patch clamp configuration.CONCLUSION: The method dissociates smooth muscle cells from rat mesenteric arterial branches. Voltage-gated channel currents can be recorded in this preparation.

  17. Analysis of potassium and calcium imaging to assay the function of opioid receptors.

    Science.gov (United States)

    Spahn, Viola; Nockemann, Dinah; Machelska, Halina

    2015-01-01

    As the activation of opioid receptors leads to the modulation of potassium and calcium channels, the ion imaging represents an attractive method to analyze the function of the receptors. Here, we describe the imaging of potassium using the FluxOR™ potassium ion channel assay, and of calcium using Fura-2 acetoxymethyl ester. Specifically, we (1) characterize the activation of the G-protein-coupled inwardly rectifying potassium 2 channel by agonists of μ- and δ-opioid receptors with the aid of the FluxOR™ assay in cultured mouse dorsal root ganglion neurons, and (2) describe calcium imaging protocols to measure capsaicin-induced transient receptor potential vanilloid 1 channel activity during opioid withdrawal in transfected human embryonic kidney 293 cells.

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

    Directory of Open Access Journals (Sweden)

    Hosein Shekofteh

    2017-02-01

    Full Text Available Introduction: Date bunch fading disorder has been one of the most important problems, which caused economic damage to date plantation area of Iran. It has been first reported on Mozafti cultivar in Kahnuj area, Kerman province. It has often been observed on soft and mid ripening cultivars such as Mozafti, Mordaseng and Kalote. Furthermore, it usually appears on Mozafti cultivar when fruits change from Khalal to Rutab stage. The most important symptoms of this disorder are sudden wilting of fruits and necrotic strips on the upper surface of the main bunch stalk. Incidence and development of these symptoms increase by high temperature, low relative humidity, and hot and dry wind. Several research studies have been carried out on this disorder so far, but the only research about the effect of nutrition on disorder was performed by Rosta (2003. The aim of the present study was to investigate the effect of calcium and potassium spray on date bunch fading and some traits of date fruit in Rigan region, Kerman province. Materials and Methods: The experiment was conducted based on randomized complete block designs with three replicates in Rigan located in east south of Kerman province, Iran, in 2012. Treatments were: T1: control, T2: spray of calcium nitrate at the concentration of 5 ppm, T3: spray of potassium sulfate at the concentration of 5 ppm, and T4: combined spray of calcium nitrate and potassium sulfate at the concentration of 5 ppm. Treatments were applied at Kimri, Hobabok and Khalal stages. Sampling was performed from 3 date palms (3 bunches from each date palm were selected randomly at the second date harvest. Totally, the traits of 200 fruits were measured in each date palm. The traits measured in the present study were: fruit length, fruit diameter, fruit weight, stone weight, stone diameter, and bunch fading percentage. Results and Discussions: According to the data of variance analysis, treatments had a significant effect on wet fruit

  19. Direct determination of calcium, sodium and potassium in fermented milk products

    Directory of Open Access Journals (Sweden)

    Kravić Snežana Ž.

    2012-01-01

    Full Text Available The aim of this study was the investigation of the possibilities of direct determination of calcium, sodium and potassium in the commercial and kombucha-based fermented milk products by flame photometry. Two procedures were used for sample preparation: simple dilution with water (direct method and extraction with mineral acid. Calcium, sodium and potassium levels determined after mentioned sample preparation methods were compared. The results showed that the differences between the values obtained for the different sample treatment were within the experimental error at the 95% confidence level. Compared to the method based on extraction with mineral acid, the direct method is efficient, faster, simpler, cheaper, and operates according to the principles of Green Chemistry. Consequently, the proposed method for the direct determination of calcium, sodium and potassium could be applied for the rapid routine analysis of the mineral content in the fermented dairy products. [Projekat Ministarstva nauke Republike Srbije, br. III 46009

  20. Immunolocalization and expression of small-conductance calcium-activated potassium channels in human myometrium

    DEFF Research Database (Denmark)

    Rosenbaum, Sofia T; Svalø, Julie; Nielsen, Karsten;

    2012-01-01

    Small-conductance calcium-activated potassium (SK3) channels have been detected in human myometrium and we have previously shown a functional role of SK channels in human myometrium in vitro. The aims of this study were to identify the precise localization of SK3 channels and to quantify SK3 mRNA...

  1. Magnesium, Calcium, Potassium, and Sodium Intakes and Risk of Stroke in Male Smokers

    NARCIS (Netherlands)

    Larsson, S.C.; Virtanen, M.J.; Mars, M.; Mannisto, S.; Pietinen, P.; Albanes, D.; Virtamo, J.

    2008-01-01

    Background A high intake of magnesium, calcium, and potassium and a low intake of sodium have been hypothesized to reduce the risk of stroke. However, prospective data relating intake of these minerals to risk of stroke are inconsistent. Methods We examined the relationship of dietary magnesium, cal

  2. Determination of experimental K-shell fluorescence yield for potassium and calcium compounds

    Indian Academy of Sciences (India)

    E Tiraşoğlu; Ö Söğüt

    2008-03-01

    K-shell fluorescence yields were experimentally determined for potassium and calcium compounds using a Si(Li) X-ray detector system (FWHM=5.96 keV at 160 eV). The samples were excited by 5.96 keV photons produced by a 55Fe radioisotope source. The experimental values are systematically lower than the theoretical values.

  3. Treatment with Potassium Bicarbonate Lowers Calcium Excretion and Bone Resorption in Older Men and Women

    Science.gov (United States)

    Bicarbonate has been implicated in bone health in older subjects on acid-producing diets in short-term studies. The objective of this study was to determine the effects of potassium bicarbonate and its components on changes in bone resorption and calcium excretion over 3 months in older men and wom...

  4. STUDY OF SODIUM, POTASSIUM, AND CALCIUM SALTS INFLUENCE ON PROTEIN STABILITY BY DIFFERENTIAL SCANNING CALORIMETRY

    Directory of Open Access Journals (Sweden)

    E. K. Tunieva

    2016-01-01

    Full Text Available Abstract Study of protein stability depending on the various technological factors allows to directionally adjust the physicochemical properties of raw meat and the quality of finished meat products. The paper investigates the possibility of using the DSC to study the influence of monovalent and divalent salts on protein thermal stability. In order to determine the effect of sodium chloride and its substitutes, potassium and calcium salts, on the thermal stability of proteins, the studies were carried out with grinded pork longissimus muscle samples salted with sodium chloride at level of 2.0% and with salt compositions containing reduced by 50% level of sodium chloride (a mixture of sodium and potassium chlorides; a mixture of sodium, potassium, and calcium chlorides using the differential scanning calorimeter DSC Q 2000 in the temperature range of 5 °C to 100 °C and the temperature change rate of 1 K/min. It was found that the addition of potassium chloride instead of 50% of sodium chloride had no significant effect on actin and myosin resistance to thermal denaturation. Meat salting using the mixture of sodium, potassium, and calcium chlorides resulted in decrease of myofibrillar proteins stability indicating the destabilizing effect of calcium on actin and myosin. A negative correlation between the magnitude of the ionic strength and the temperature of myosin and actin denaturation has been found. The correlation coefficients were minus 0.99 and minus 0.95 for myosin and actin respectively. Reduction of denaturation temperature for myofibrillar proteins in the presence of calcium chloride opens perspectives to study the possibility of heat treatment at lower temperatures for meat products with reduced sodium content.

  5. Large-conductance calcium-activated potassium channels facilitate transmitter release in salamander rod synapse.

    Science.gov (United States)

    Xu, Jian Wei; Slaughter, Malcolm M

    2005-08-17

    Large-conductance calcium-activated potassium (BK) channels are colocalized with calcium channels at sites of exocytosis at the presynaptic terminals throughout the nervous system. It is expected that their activation would provide negative feedback to transmitter release, but the opposite is sometimes observed. Attempts to resolve this apparent paradox based on alterations in action potential waveform have been ambiguous. In an alternative approach, we investigated the influence of this channel on neurotransmitter release in a nonspiking neuron, the salamander rod photoreceptors. Surprisingly, the BK channel facilitates calcium-mediated transmitter release from rods. The two presynaptic channels form a positive coupled loop. Calcium influx activates the BK channel current, leading to potassium efflux that increases the calcium current. The normal physiological voltage range of the rod is well matched to the dynamics of this positive loop. When the rod is further depolarized, then the hyperpolarizing BK channel current exceeds its facilitatory effect, causing truncation of transmitter release. Thus, the calcium channel-BK channel linkage performs two functions at the synapse: nonlinear potentiator and safety brake.

  6. Control of anterior pituitary cell excitability by calcium-activated potassium channels.

    Science.gov (United States)

    Shipston, Michael J

    2017-06-05

    In anterior pituitary endocrine cells, large (BK), small (SK) and intermediate (IK) conductance calcium activated potassium channels are key determinants in shaping cellular excitability in a cell type- and context-specific manner. Indeed, these channels are targeted by multiple signaling pathways that stimulate or inhibit cellular excitability. BK channels can, paradoxically, both promote electrical bursting as well as terminate bursting and spiking dependent upon intrinsic BK channel properties and proximity to voltage gated calcium channels in somatotrophs, lactotrophs and corticotrophs. In contrast, SK channels are predominantly activated by calcium released from intracellular IP3-sensitive calcium stores and mediate membrane hyperpolarization in cells including gonadotrophs and corticotrophs. IK channels are predominantly expressed in corticotrophs where they limit membrane excitability. A major challenge for the future is to determine the cell-type specific molecular composition of calcium-activated potassium channels and how they control anterior pituitary hormone secretion as well as other calcium-dependent processes. Copyright © 2017. Published by Elsevier B.V.

  7. Why and how to implement sodium, potassium, calcium, and magnesium changes in food items and diets?

    Science.gov (United States)

    Karppanen, H; Karppanen, P; Mervaala, E

    2005-12-01

    The present average sodium intakes, approximately 3000-4500 mg/day in various industrialised populations, are very high, that is, 2-3-fold in comparison with the current Dietary Reference Intake (DRI) of 1500 mg. The sodium intakes markedly exceed even the level of 2500 mg, which has been recently given as the maximum level of daily intake that is likely to pose no risk of adverse effects on blood pressure or otherwise. By contrast, the present average potassium, calcium, and magnesium intakes are remarkably lower than the recommended intake levels (DRI). In USA, for example, the average intake of these mineral nutrients is only 35-50% of the recommended intakes. There is convincing evidence, which indicates that this imbalance, that is, the high intake of sodium on one hand and the low intakes of potassium, calcium, and magnesium on the other hand, produce and maintain elevated blood pressure in a big proportion of the population. Decreased intakes of sodium alone, and increased intakes of potassium, calcium, and magnesium each alone decrease elevated blood pressure. A combination of all these factors, that is, decrease of sodium, and increase of potassium, calcium, and magnesium intakes, which are characteristic of the so-called Dietary Approaches to Stop Hypertension diets, has an excellent blood pressure lowering effect. For the prevention and basic treatment of elevated blood pressure, various methods to decrease the intake of sodium and to increase the intakes of potassium, calcium, and magnesium should be comprehensively applied in the communities. The so-called 'functional food/nutraceutical/food-ceutical' approach, which corrects the mineral nutrient composition of extensively used processed foods, is likely to be particularly effective in producing immediate beneficial effects. The European Union and various governments should promote the availability and use of such healthier food compositions by tax reductions and other policies, which make the

  8. Release of Potassium Ion and Calcium Ion from Phosphorylcholine Group Bearing Hydrogels

    Directory of Open Access Journals (Sweden)

    Kazuhiko Ishihara

    2013-11-01

    Full Text Available In an attempt to recreate the microenvironment necessary for directed hematopoietic stem cell differentiation, control over the amount of ions available to the cells is necessary. The release of potassium ion and calcium ion via the control of cross-linking density of a poly(2-hydroxyethyl methacrylate (pHEMA-based hydrogel containing 1 mol % 2-methacryloyloxyethyl phosphorylcholine (MPC and 5 mol % oligo(ethylene glycol (400 monomethacrylate [OEG(400MA] was investigated. Tetra(ethylene glycol diacrylate (TEGDA, the cross-linker, was varied over the range of 1–12 mol %. Hydrogel discs (ϕ = 4.5 mm and h = 2.0 mm were formed by UV polymerization within silicone isolators to contain 1.0 M CaCl2 and 0.1 M KCl, respectively. Isothermal release profiles, were measured at 37 °C in 4-(2-hydroxyethyl-1-piperazineethanesulfonic acid sodium salt (HEPES buffer using either calcium ion or potassium ion selective electrodes (ISE. The resulting release profiles were found to be independent of cross-linking density. Average (n = 3 release profiles were fit to five different release models with the Korsmeyer-Peppas equation, a porous media transport model, exhibiting the greatest correlation (R2 > 0.95. The diffusion exponent, n was calculated to be 0.24 ± 0.02 and 0.36 ± 0.04 for calcium ion and potassium ion respectively indicating non-Fickian diffusion. The resulting diffusion coefficients were calculated to be 2.6 × 10−6 and 11.2 × 10−6 cm2/s, which compare well to literature values of 2.25 × 10−6 and 19.2 × 10−6 cm2/s for calcium ion and potassium ion, respectively.

  9. Non-destructive measurement of calcium and potassium in apple and pear using handheld x-ray fluorescence

    Directory of Open Access Journals (Sweden)

    Lee A Kalcsits

    2016-04-01

    Full Text Available Calcium and potassium are essential for cell signalling, ion homeostasis and cell wall strength in plants. Unlike nutrients such as nitrogen and potassium, calcium is immobile in plants. Localized calcium deficiencies result in agricultural losses; particularly for fleshy horticultural crops in which elemental imbalances in fruit contribute to the development of physiological disorders such as bitter pit in apple and cork spot in pear. Currently, elemental analysis of plant tissue is destructive, time consuming and costly. This is a limitation for nutrition studies related to calcium in plants. Handheld portable x-ray fluorescence (XRF can be used to non-destructively measure elemental concentrations. The main objective was to test if handheld XRF can be used for semi-quantitative calcium and potassium analysis of in-tact apple and pear. Semi-quantitative measurements for individual fruit were compared to results obtained from traditional lab analysis. Here, we observed significant correlations between handheld XRF measurements of calcium and potassium and concentrations determined using MP-AES lab analysis. Pearson correlation coefficients ranged from 0.73 and 0.97. Furthermore, measuring apple and pear using handheld XRF identified spatial variability in calcium and potassium concentrations on the surface of individual fruit. This variability may contribute to the development of localized nutritional imbalances. This highlights the importance of understanding spatial and temporal variability in elemental concentrations in plant tissue. Handheld XRF is a relatively high-throughput approach for measuring calcium and potassium in plant tissue. It can be used in conjunction with traditional lab analysis to better understand spatial and temporal patterns in calcium and potassium uptake and distribution within an organ, plant or across the landscape.

  10. SLO BK Potassium Channels Couple Gap Junctions to Inhibition of Calcium Signaling in Olfactory Neuron Diversification.

    Science.gov (United States)

    Alqadah, Amel; Hsieh, Yi-Wen; Schumacher, Jennifer A; Wang, Xiaohong; Merrill, Sean A; Millington, Grethel; Bayne, Brittany; Jorgensen, Erik M; Chuang, Chiou-Fen

    2016-01-01

    The C. elegans AWC olfactory neuron pair communicates to specify asymmetric subtypes AWCOFF and AWCON in a stochastic manner. Intercellular communication between AWC and other neurons in a transient NSY-5 gap junction network antagonizes voltage-activated calcium channels, UNC-2 (CaV2) and EGL-19 (CaV1), in the AWCON cell, but how calcium signaling is downregulated by NSY-5 is only partly understood. Here, we show that voltage- and calcium-activated SLO BK potassium channels mediate gap junction signaling to inhibit calcium pathways for asymmetric AWC differentiation. Activation of vertebrate SLO-1 channels causes transient membrane hyperpolarization, which makes it an important negative feedback system for calcium entry through voltage-activated calcium channels. Consistent with the physiological roles of SLO-1, our genetic results suggest that slo-1 BK channels act downstream of NSY-5 gap junctions to inhibit calcium channel-mediated signaling in the specification of AWCON. We also show for the first time that slo-2 BK channels are important for AWC asymmetry and act redundantly with slo-1 to inhibit calcium signaling. In addition, nsy-5-dependent asymmetric expression of slo-1 and slo-2 in the AWCON neuron is necessary and sufficient for AWC asymmetry. SLO-1 and SLO-2 localize close to UNC-2 and EGL-19 in AWC, suggesting a role of possible functional coupling between SLO BK channels and voltage-activated calcium channels in AWC asymmetry. Furthermore, slo-1 and slo-2 regulate the localization of synaptic markers, UNC-2 and RAB-3, in AWC neurons to control AWC asymmetry. We also identify the requirement of bkip-1, which encodes a previously identified auxiliary subunit of SLO-1, for slo-1 and slo-2 function in AWC asymmetry. Together, these results provide an unprecedented molecular link between gap junctions and calcium pathways for terminal differentiation of olfactory neurons.

  11. Synthesis of porous poly(acrylamide hydrogels using calcium carbonate and its application for slow release of potassium nitrate

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available Porous poly(acrylamide was synthesized using calcium carbonate microparticles and subsequent acid treatment to remove the calcium carbonate. Methylenebisacrylamide and ammonium persulfate/sodium metabisulfite were used as crosslinking agent and redox initiator, respectively. The porous structure of resulted hydrogels was confirmed using SEM micrographs. The effect of methylenebisacrylamide concentration and calcium carbonate amount on the swelling of the hydrogels was investigated. The results showed that the effect of methylenebisacrylamide and calcium carbonate variables on the swelling is reverse. The hydrogels were subsequently utilized for the loading of potassium nitrate. Potassium nitrate as active agent was loaded into hydrogels and subsequently the release of this active agent was investigated. In these series of investigation, the effect of content of loading, methylenebisacrylamide and calcium carbonate amount on the release of potassium nitrate from hydrogels was investigated.

  12. Potassium

    Science.gov (United States)

    ... blackberries Root vegetables, such as carrots and potatoes Citrus fruits, such as oranges and grapefruit Your kidneys help to keep the right amount of potassium in your body. If you have chronic kidney disease, your kidneys may not remove extra potassium from ...

  13. Development of voltage-dependent calcium, sodium, and potassium currents in Xenopus spinal neurons.

    Science.gov (United States)

    O'Dowd, D K; Ribera, A B; Spitzer, N C

    1988-03-01

    Action potentials of embryonic nerve and muscle cells often have a different ionic dependence and longer duration than those of mature cells. The action potential of spinal cord neurons from Xenopus laevis exhibits a prominent calcium component at early stages of development that diminishes with age as the impulse becomes principally sodium dependent. Whole-cell voltage-clamp analysis has been undertaken to characterize the changes in membrane currents during development of these neurons in culture. Four voltage-dependent currents of cells were identified and examined during the first day in vitro, when most of the change in the action potential occurs. There are no changes in the peak density of the calcium current (ICa), its voltage dependence, or time to half-maximal activation; a small increase in inactivation is apparent. The major change in sodium current (INa) is a 2-fold increase in its density. In addition, more subtle changes in the kinetics of the macroscopic sodium current were noted. The peak density of voltage-dependent potassium current (IKv) increases 3-fold, and this current becomes activated almost twice as fast. No changes were noted in the extent of its inactivation. The calcium-dependent potassium current (IKc) consists of an inactivating and a sustained component. The former increases 2-fold in peak current density, and the latter increases similarly at less depolarized voltages. The changes in these currents contribute to the decrease in duration and the change in ionic dependence of the impulse.

  14. Potassium

    Science.gov (United States)

    ... high in potassium include bananas, cantaloupe, grapefruit, oranges, tomato or prune juice, honeydew melons, prunes, molasses and ... of a Heart Attack 10 Angina (Chest Pain) *Red Dress ™ DHHS, Go Red ™ AHA ; National Wear Red ...

  15. Calcium-Activated Potassium Channels in Ischemia Reperfusion: A Brief Update

    Directory of Open Access Journals (Sweden)

    Jean-Yves eTano

    2014-10-01

    Full Text Available Ischemia and reperfusion (IR injury constitutes one of the major causes of cardiovascular morbidity and mortality. The discovery of new therapies to block/mediate the effects of IR is therefore an important goal in the biomedical sciences. Dysfunction associated with IR involves modification of calcium-activated potassium channels (KCa through different mechanisms, which are still under study. Respectively, the KCa family, major contributors to plasma membrane calcium influx in cells and essential players in the regulation of the vascular tone are interesting candidates. This family is divided into two groups including the large conductance (BKCa and the small/intermediate conductance (SKCa/IKCa K+ channels. In the heart and brain, these channels have been described to offer protection against IR injury. BKCa and SKCa channels deserve special attention since new data demonstrate that these channels are also expressed in mitochondria. More studies are however needed to fully determine their potential use as therapeutic targets.

  16. Nitric oxide regulates neuronal activity via calcium-activated potassium channels.

    Directory of Open Access Journals (Sweden)

    Lei Ray Zhong

    Full Text Available Nitric oxide (NO is an unconventional membrane-permeable messenger molecule that has been shown to play various roles in the nervous system. How NO modulates ion channels to affect neuronal functions is not well understood. In gastropods, NO has been implicated in regulating the feeding motor program. The buccal motoneuron, B19, of the freshwater pond snail Helisoma trivolvis is active during the hyper-retraction phase of the feeding motor program and is located in the vicinity of NO-producing neurons in the buccal ganglion. Here, we asked whether B19 neurons might serve as direct targets of NO signaling. Previous work established NO as a key regulator of growth cone motility and neuronal excitability in another buccal neuron involved in feeding, the B5 neuron. This raised the question whether NO might modulate the electrical activity and neuronal excitability of B19 neurons as well, and if so whether NO acted on the same or a different set of ion channels in both neurons. To study specific responses of NO on B19 neurons and to eliminate indirect effects contributed by other cells, the majority of experiments were performed on single cultured B19 neurons. Addition of NO donors caused a prolonged depolarization of the membrane potential and an increase in neuronal excitability. The effects of NO could mainly be attributed to the inhibition of two types of calcium-activated potassium channels, apamin-sensitive and iberiotoxin-sensitive potassium channels. NO was found to also cause a depolarization in B19 neurons in situ, but only after NO synthase activity in buccal ganglia had been blocked. The results suggest that NO acts as a critical modulator of neuronal excitability in B19 neurons, and that calcium-activated potassium channels may serve as a common target of NO in neurons.

  17. Control of spontaneous firing patterns by the selective coupling of calcium currents to calcium-activated potassium currents in striatal cholinergic interneurons.

    Science.gov (United States)

    Goldberg, Joshua A; Wilson, Charles J

    2005-11-02

    The spontaneous firing patterns of striatal cholinergic interneurons are sculpted by potassium currents that give rise to prominent afterhyperpolarizations (AHPs). Large-conductance calcium-activated potassium (BK) channel currents contribute to action potential (AP) repolarization; small-conductance calcium-activated potassium channel currents generate an apamin-sensitive medium AHP (mAHP) after each AP; and bursts of APs generate long-lasting slow AHPs (sAHPs) attributable to apamin-insensitive currents. Because all these currents are calcium dependent, we conducted voltage- and current-clamp whole-cell recordings while pharmacologically manipulating calcium channels of the plasma membrane and intracellular stores to determine what sources of calcium activate the currents underlying AP repolarization and the AHPs. The Cav2.2 (N-type) blocker omega-conotoxin GVIA (1 microM) was the only blocker that significantly reduced the mAHP, and it induced a transition to rhythmic bursting in one-third of the cells tested. Cav1 (L-type) blockers (10 microM dihydropyridines) were the only ones that significantly reduced the sAHP. When applied to cells induced to burst with apamin, dihydropyridines reduced the sAHPs and abolished bursting. Depletion of intracellular stores with 10 mM caffeine also significantly reduced the sAHP current and reversibly regularized firing. Application of 1 microM omega-conotoxin MVIIC (a Cav2.1/2.2 blocker) broadened APs but had a negligible effect on APs in cells in which BK channels were already blocked by submillimolar tetraethylammonium chloride, indicating that Cav2.1 (Q-type) channels provide the calcium to activate BK channels that repolarize the AP. Thus, calcium currents are selectively coupled to the calcium-dependent potassium currents underlying the AHPs, thereby creating mechanisms for control of the spontaneous firing patterns of these neurons.

  18. Analysis of the effects of calcium or magnesium on voltage-clamp currents in perfused squid axons bathed in solutions of high potassium.

    Science.gov (United States)

    Rojas, E; Taylor, R E; Atwater, I; Bezanilla, F

    1969-10-01

    Isolated axons from the squid, Dosidicus gigas, were internally perfused with potassium fluoride solutions. Membrane currents were measured following step changes of membrane potential in a voltage-clamp arrangement with external isosmotic solution changes in the order: potassium-free artificial seawater; potassium chloride; potassium chloride containing 10, 25, 40 or 50, mM calcium or magnesium; and potassium-free artificial seawater. The following results suggest that the currents measured under voltage clamp with potassium outside and inside can be separated into two components and that one of them, the predominant one, is carried through the potassium system. (a) Outward currents in isosmotic potassium were strongly and reversibly reduced by tetraethylammonium chloride. (b) Without calcium or magnesium a progressive increase in the nontime-dependent component of the currents (leakage) occurred. (c) The restoration of calcium or magnesium within 15-30 min decreases this leakage. (d) With 50 mM divalent ions the steady-state current-voltage curve was nonlinear with negative resistance as observed in intact axons in isosmotic potassium. (e) The time-dependent components of the membrane currents were not clearly affected by calcium or magnesium. These results show a strong dependence of the leakage currents on external calcium or magnesium concentration but provide no support for the involvement of calcium or magnesium in the kinetics of the potassium system.

  19. The calcium-activated potassium channel KCa3.1 is an important modulator of hepatic injury

    DEFF Research Database (Denmark)

    Møller, Linda Maria Sevelsted; Fialla, Annette Dam; Schierwagen, Robert

    2016-01-01

    The calcium-activated potassium channel KCa3.1 controls different cellular processes such as proliferation and volume homeostasis. We investigated the role of KCa3.1 in experimental and human liver fibrosis. KCa3.1 gene expression was investigated in healthy and injured human and rodent liver. Ef...

  20. Influence of pre-harvest calcium, potassium and triazole application on the proteome of apple at harvest

    NARCIS (Netherlands)

    Buts, Kim; Hertog, M.L.A.T.M.; Ho, Quang Tri; America, A.H.P.; Cordewener, J.H.G.; Vercammen, J.; Carpentier, S.C.; Nicolaï, Bart

    2016-01-01

    Braeburn browning disorder is a storage disease characterised by flesh browning and lens-shaped cavities. The incidence of this postharvest diorder is known to be affected by pre-harvest application of fertilisers and triazole-based fungicides. Recent work has shown that calcium and potassium reduce

  1. Histamine potentiates neuronal excitation by blocking a calcium-dependent potassium conductance.

    Science.gov (United States)

    Haas, H L

    1984-04-01

    Histaminergic neurones send their axons to the whole forebrain. The diffuse projection is consistent with a modulatory role of these pathways. In hippocampal slices from rats a mechanism for this modulation is described, on pyramidal neurones of the CA 1 area: Strong excitations induced by intracellular current injection, ionophoretic administration of glutamate or synaptic stimulation normally restrict themselves by the activation of the calcium-dependent potassium current (gK(Ca) ). This current causes a long lasting afterhyperpolarization and an accommodation of firing. Their block by histamine and impromidine (reversed by metiamide and cimetidine) leads to a profound potentiation of excitatory signals. It is suggested that HA, through H2 receptors, accelerates the removal of intracellular free Ca++ ions.

  2. Synthesis of potassium and calcium uranium vanadates, analogues of Carnotite and meta tyuyamunite minerals

    Energy Technology Data Exchange (ETDEWEB)

    Requena Y, J. L.; Reyes C, M.; Torres M, E.; Lardizabal, D.; Montero C, M. E. [Centro de Investigacion en Materiales Avanzados, S. C., Miguel de Cervantes No. 120, Complejo Industrial Chihuahua, 31109 Chihuahua (Mexico); Riveros, H., E-mail: elena.montero@cimav.edu.mx [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2012-06-15

    The aim of this study was to develop a synthesis of meta tyuyamunite (Ca(VUO{sub 6}){sub 2}{center_dot}3-5H{sub 2}O) and carnotite (KVUO{sub 6}{center_dot}1-3H{sub 2}O) under hydrothermal conditions. Also, crystals obtained from this synthesis were compared with crystals from melting method. The analyses of synthesis products were performed by X-ray techniques. X-ray diffraction was used for both species identification, whereas scanning electron microscopy was used to analyze their morphology and elemental composition. Both uranium vanadates were positive synthesized under hydrothermal conditions, besides, their morphology presents particles agglomerates. Calcium uranium vanadate agglomerates contain well-defined crystals, whereas potassium uranium vanadate agglomerates consist in fine powder particles. (Author)

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

    Science.gov (United States)

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

    2002-12-01

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

  4. Osteoclast spreading kinetics are correlated with an oscillatory activation of a calcium-dependent potassium current.

    Science.gov (United States)

    Espinosa, Leon; Paret, Laurent; Ojeda, Carlos; Tourneur, Yves; Delmas, Pierre D; Chenu, Chantal

    2002-10-01

    Cell movement and spreading involve calcium-dependent processes and ionic channel activation. During bone resorption, osteoclasts alternate between spread, motile and resorptive phases. We investigated whether the electrical membrane properties of osteoclasts were linked to their membrane morphological changes. Rabbit osteoclasts were recorded by time-lapse videomicroscopy performed simultaneously with patch-clamp whole cell and single channel recordings. Original image analysis methods were developed and used to demonstrate for the first time an oscillatory activation of a spontaneous membrane current in osteoclasts, which is directly correlated to the membrane movement rate. This current was identified as a calcium-dependent potassium current (IK(Ca)) that is sensitive to both charybdotoxin and apamin and was generated by a channel with unitary conductance of approximately 25+/-2 pS. Blockade of this current also decreased osteoclast spreading and inhibited bone resorption in vitro, demonstrating a physiological role for this current in osteoclast activity. These results establish for the first time a temporal correlation between lamellipodia formation kinetics and spontaneous peaks of IK(Ca), which are both involved in the control of osteoclast spreading and bone resorption.

  5. Contribution of presynaptic calcium-activated potassium currents to transmitter release regulation in cultured Xenopus nerve-muscle synapses.

    Science.gov (United States)

    Pattillo, J M; Yazejian, B; DiGregorio, D A; Vergara, J L; Grinnell, A D; Meriney, S D

    2001-01-01

    Using Xenopus nerve-muscle co-cultures, we have examined the contribution of calcium-activated potassium (K(Ca)) channels to the regulation of transmitter release evoked by single action potentials. The presynaptic varicosities that form on muscle cells in these cultures were studied directly using patch-clamp recording techniques. In these developing synapses, blockade of K(Ca) channels with iberiotoxin or charybdotoxin decreased transmitter release by an average of 35%. This effect would be expected to be caused by changes in the late phases of action potential repolarization. We hypothesize that these changes are due to a reduction in the driving force for calcium that is normally enhanced by the local hyperpolarization at the active zone caused by potassium current through the K(Ca) channels that co-localize with calcium channels. In support of this hypothesis, we have shown that when action potential waveforms were used as voltage-clamp commands to elicit calcium current in varicosities, peak calcium current was reduced only when these waveforms were broadened beginning when action potential repolarization was 20% complete. In contrast to peak calcium current, total calcium influx was consistently increased following action potential broadening. A model, based on previously reported properties of ion channels, faithfully reproduced predicted effects on action potential repolarization and calcium currents. From these data, we suggest that the large-conductance K(Ca) channels expressed at presynaptic varicosities regulate transmitter release magnitude during single action potentials by altering the rate of action potential repolarization, and thus the magnitude of peak calcium current.

  6. The large-conductance calcium-activated potassium channel holds the key to the conundrum of familial hypokalemic periodic paralysis.

    Science.gov (United States)

    Kim, June-Bum; Kim, Sung-Jo; Kang, Sun-Yang; Yi, Jin Woong; Kim, Seung-Min

    2014-10-01

    Familial hypokalemic periodic paralysis (HOKPP) is an autosomal dominant channelopathy characterized by episodic attacks of muscle weakness and hypokalemia. Mutations in the calcium channel gene, CACNA1S, or the sodium channel gene, SCN4A, have been found to be responsible for HOKPP; however, the mechanism that causes hypokalemia remains to be determined. The aim of this study was to improve the understanding of this mechanism by investigating the expression of calcium-activated potassium (KCa) channel genes in HOKPP patients. We measured the intracellular calcium concentration with fura-2-acetoxymethyl ester in skeletal muscle cells of HOKPP patients and healthy individuals. We examined the mRNA and protein expression of KCa channel genes (KCNMA1, KCNN1, KCNN2, KCNN3, and KCNN4) in both cell types. Patient cells exhibited higher cytosolic calcium levels than normal cells. Quantitative reverse transcription polymerase chain reaction analysis showed that the mRNA levels of the KCa channel genes did not significantly differ between patient and normal cells. However, western blot analysis showed that protein levels of the KCNMA1 gene, which encodes KCa1.1 channels (also called big potassium channels), were significantly lower in the membrane fraction and higher in the cytosolic fraction of patient cells than normal cells. When patient cells were exposed to 50 mM potassium buffer, which was used to induce depolarization, the altered subcellular distribution of BK channels remained unchanged. These findings suggest a novel mechanism for the development of hypokalemia and paralysis in HOKPP and demonstrate a connection between disease-associated mutations in calcium/sodium channels and pathogenic changes in nonmutant potassium channels.

  7. Differential regulation of voltage- and calcium-activated potassium channels in human B lymphocytes.

    Science.gov (United States)

    Partiseti, M; Choquet, D; Diu, A; Korn, H

    1992-06-01

    The expression and characteristics of K+ channels of human B lymphocytes were studied by using single and whole-cell patch-clamp recordings. They were gated by depolarization (voltage-gated potassium current, IKv, 11-20 pS) and by an increase in intracellular Ca2+ concentration (calcium-activated potassium current, IKCa, 26 pS), respectively. The level of expression of these channels was correlated with the activational status of the cell. Both conductances are blocked by tetraethylammonium, verapamil, and charybdotoxin, and are insensitive to apamin; 4-aminopyridine blocks IK, preferentially. We used a protein kinase C activator (PMA) or antibodies to membrane Ig (anti-mu) to activate resting splenocytes in culture. Although IKv was recorded in the majority of the resting lymphocytic population, less than 20% of the activated cells expressed this conductance. However, in this subset the magnitude of IKv was 20-fold larger than in resting cells. On the other hand, IKCa was detected in nearly one half of the resting cells, whereas all activated cells expressed this current. The magnitude of IKCa was, on average, 30 times larger in activated than in nonactivated cells. These results probably reflect that during the course of activation 1) the number of voltage-dependent K+ channels per cell decreases and increases in a small subset and 2) the number of Ca(2+)-dependent K+ channels per cell increases in all cells. We suggest that the expression of functional Ca(2+)- and voltage-activated K+ channels are under the control of different regulatory signals.

  8. Calcium sensor kinase activates potassium uptake systems in gland cells of Venus flytraps.

    Science.gov (United States)

    Scherzer, Sönke; Böhm, Jennifer; Krol, Elzbieta; Shabala, Lana; Kreuzer, Ines; Larisch, Christina; Bemm, Felix; Al-Rasheid, Khaled A S; Shabala, Sergey; Rennenberg, Heinz; Neher, Erwin; Hedrich, Rainer

    2015-06-09

    The Darwin plant Dionaea muscipula is able to grow on mineral-poor soil, because it gains essential nutrients from captured animal prey. Given that no nutrients remain in the trap when it opens after the consumption of an animal meal, we here asked the question of how Dionaea sequesters prey-derived potassium. We show that prey capture triggers expression of a K(+) uptake system in the Venus flytrap. In search of K(+) transporters endowed with adequate properties for this role, we screened a Dionaea expressed sequence tag (EST) database and identified DmKT1 and DmHAK5 as candidates. On insect and touch hormone stimulation, the number of transcripts of these transporters increased in flytraps. After cRNA injection of K(+)-transporter genes into Xenopus oocytes, however, both putative K(+) transporters remained silent. Assuming that calcium sensor kinases are regulating Arabidopsis K(+) transporter 1 (AKT1), we coexpressed the putative K(+) transporters with a large set of kinases and identified the CBL9-CIPK23 pair as the major activating complex for both transporters in Dionaea K(+) uptake. DmKT1 was found to be a K(+)-selective channel of voltage-dependent high capacity and low affinity, whereas DmHAK5 was identified as the first, to our knowledge, proton-driven, high-affinity potassium transporter with weak selectivity. When the Venus flytrap is processing its prey, the gland cell membrane potential is maintained around -120 mV, and the apoplast is acidified to pH 3. These conditions in the green stomach formed by the closed flytrap allow DmKT1 and DmHAK5 to acquire prey-derived K(+), reducing its concentration from millimolar levels down to trace levels.

  9. Delay in onset of metabolic alkalosis during regional citrate anti-coagulation in continous renal replacement therapy with calcium-free replacement solution

    Directory of Open Access Journals (Sweden)

    See Kay

    2009-01-01

    Full Text Available Regional citrate anti-coagulation for continuous renal replacement therapy chelates calcium to produce the anti- coagulation effect. We hypothesise that a calcium-free replacement solution will require less citrate and produce fewer metabolic side effects. Fifty patients, in a Medical Intensive Care Unit of a tertiary teaching hospital (25 in each group, received continuous venovenous hemofiltration using either calcium-containing or calcium-free replacement solutions. Both groups had no significant differences in filter life, metabolic alkalosis, hypernatremia, hypocalcemia, and hypercalcemia. However, patients using calcium-containing solution developed metabolic alkalosis earlier, compared to patients using calcium-free solution (mean 24.6 hours,CI 0.8-48.4 vs. 37.2 hours, CI 9.4-65, P = 0.020. When calcium-containing replacement solution was used, more citrate was required (mean 280ml/h, CI 227.2-332.8 vs. 265ml/h, CI 203.4-326.6, P = 0.069, but less calcium was infused (mean 21.2 ml/h, CI 1.2-21.2 vs 51.6ml/h, CI 26.8-76.4, P ≤ 0.0001.

  10. Control of Spontaneous Firing Patterns by the Selective Coupling of Calcium Currents to Calcium Activated Potassium Currents in Striatal Cholinergic Interneurons

    OpenAIRE

    Goldberg, Joshua A.; Wilson, Charles J.

    2005-01-01

    The spontaneous firing patterns of striatal cholinergic interneurons are sculpted by potassium currents that give rise to prominent afterhyperpolarizations (AHPs): BK currents contribute to action potential (AP) repolarization; SK currents generate an apamin-sensitive medium AHP (mAHP) following each AP; and bursts of APs generate long-lasting slow AHPs (sAHPs) due to apamin-insensitive currents. As all these currents are calcium-dependent, we conducted voltage- and current-clamp whole-cell r...

  11. Calcium and potassium dynamics and biopurification in two populations of the subalpine evergreen shrub Rhododendron ferrugineum

    Directory of Open Access Journals (Sweden)

    Charles Marty

    2014-06-01

    Full Text Available Calcium (Ca and potassium (K are important acidity neutralizers in soils and essential elements for plants. These two elements are known to undergo a biopurification within the plant (i.e., discrimination against strontium (Sr and barium (Ba for Ca, and rubidium (Rb for K. However variations in the magnitude of this process between plant populations have rarely been reported, especially in high altitude, nutrient-depleted habitats. Concentrations of Ca, Sr, Ba, K and Rb were measured in roots, stems and in the different leaf cohorts in two populations of the evergreen shrub R. ferrugineum located at a granitic high elevation site. Calcium and K concentrations in leaves were respectively ~5 and 3 times higher than in roots and stems. Ca concentration increased while K concentration decreased with leaf age. The ratios Ca/Sr, Ca/Ba and K/Rb increased from roots to leaves, revealing a significant biopurification especially between stems and leaves. This phenomenon was higher for Ca than for K, with Ca/Sr and Ca/Ba ratios more than twice and 4 times higher in leaves than in roots, respectively, while K/Rb ratio in leaves was only 50% higher than in roots. Ca/Sr ratio decreased whereas K/Rb increased with leaf age. While the first could result from a "chromatographic effect" of the vascular column, the latter suggests the existence of biopurification mechanisms during influx/efflux of K from the leaf. Surprisingly, the magnitude of Ca biopurification varied between populations on a small geographical scale suggesting that Ca/Sr ratio should be used cautiously for plant Ca source identification.

  12. Influence of portland cement replacement in high calcium fly ash geopolymer paste

    Directory of Open Access Journals (Sweden)

    Tanakorn Phoo-ngernkham

    2014-03-01

    Full Text Available This article presents the influence of ordinary Portland cement (OPC replacement in high calcium fly ash (FA geopolymer paste. FA was used to replace OPC at the rate of 5, 10 and 15% by mass of binder. Sodium silicate (Na2SiO3 and 10 molar sodium hydroxide (NaOH solutions were used as the alkaline solution in the reaction. The Na2SiO3/NaOH ratio of 2.0 and the liquid/binder (L/B ratio of 0.60 were used in all mixtures. The results of increase OPC replacement, the setting time and compressive strain capacity decreased while the compressive strength and modulus of elasticity increased. The compressive strength and modulus of elasticity at 28 days of geopolymer pastes with 15% OPC replacement were 36.7 MPa and 13,300 MPa, respectively.

  13. Activation of calcium-dependent potassium channels in rat brain neurons by neurotrophin-3 and nerve growth factor

    OpenAIRE

    Holm, Ninna R.; Christophersen, Palle; Olesen, Søren P.; Gammeltoft, Steen

    1997-01-01

    The neurotrophins are signaling factors that are essential for survival and differentiation of distinct neuronal populations during the development and regeneration of the nervous system. The long-term effects of neurotrophins have been studied in detail, but little is known about their acute effects on neuronal activity. Here we use permeabilized whole-cell patch clamp to demonstrate that neurotrophin-3 (NT-3) and nerve growth factor activate calcium-dependent, paxilline-sensitive potassium ...

  14. [Biochemical effects of potassium citrate in the treatment of calcium oxalate lithiasis].

    Science.gov (United States)

    Conte Visús, A; Ibarz Servio, L; Arrabal Martín, M; Ibarz Navarro, J M; Ruiz Marcellán, F J

    1994-03-01

    The serum and urinary biochemical changes observed one month and six months after oral potassium citrate therapy (600 mEq/day) in 119 patients with calcium oxalate calculi were compared with those of 16 untreated cases with lithiasis. The patients that received treatment were previously divided into two groups: group A comprised 61 hypocitraturic patients and group B comprised 58 patients with other urinary disorders who were normo or hypocitraturic. The urinary pH increased by approximately half a point in both treated groups. In group A calciuria increased slightly from 180 +/- 8 to 216 +/- 10 mg/24 h but remained within the normal ranges. Creatinuria, oxaluria, uricosuria and diuresis showed no changes. Citraturia increased very significantly in both groups and more markedly in the hypocitraturic group of patients (from 198 +/- 13 to 476 +/- 35 mg/24 h). The LRC (lithogenic risk coefficient = Ca/Cit x Diu) dropped by 50%. The patients tolerated the treatment regimen well; of the 119 treated patients, only 11 abandoned treatment due to GI intolerance.

  15. Potassium silicate and calcium silicate on the resistance of soybean to Phakopsora pachyrhizi infection

    Directory of Open Access Journals (Sweden)

    Maria Fernanda Cruz

    2013-01-01

    Full Text Available The control of Asian Soybean Rust (ASR, caused by Phakopsora pachyrhizi, has been difficult due to the aggressiveness of the pathogen and the lack of resistant cultivars. The objective of this study was to evaluate the effects of spray of potassium silicate (PS and soil amendment with calcium silicate (CS on soybean resistance to ASR. The PS solution was sprayed to leaves 24 hours prior to fungal inoculation while CS was amended to the soil at thirty-five days before sowing. The infection process of P. pachyrhizi was investigated by scanning electron microscopy. The uredia on leaves of plants sprayed with PS were smaller and more compact than those observed on the leaves of plants grown in soil amended with CS or in soil non-amended with CS (control treatment. On leaves of plants from the control treatment, uredia produced many urediniospores at 9 days after inoculation, and the ASR severity was 15, 8 and 9%, respectively, for plants from control, PS and CS treatments. In conclusion, the spray of PS contributed to reduce the number of uredia per cm² of leaf area and both PS spray and CS resulted in lower ASR symptoms.

  16. Molecular mechanism underlying β1 regulation in voltage- and calcium-activated potassium (BK) channels.

    Science.gov (United States)

    Castillo, Karen; Contreras, Gustavo F; Pupo, Amaury; Torres, Yolima P; Neely, Alan; González, Carlos; Latorre, Ramon

    2015-04-14

    Being activated by depolarizing voltages and increases in cytoplasmic Ca(2+), voltage- and calcium-activated potassium (BK) channels and their modulatory β-subunits are able to dampen or stop excitatory stimuli in a wide range of cellular types, including both neuronal and nonneuronal tissues. Minimal alterations in BK channel function may contribute to the pathophysiology of several diseases, including hypertension, asthma, cancer, epilepsy, and diabetes. Several gating processes, allosterically coupled to each other, control BK channel activity and are potential targets for regulation by auxiliary β-subunits that are expressed together with the α (BK)-subunit in almost every tissue type where they are found. By measuring gating currents in BK channels coexpressed with chimeras between β1 and β3 or β2 auxiliary subunits, we were able to identify that the cytoplasmic regions of β1 are responsible for the modulation of the voltage sensors. In addition, we narrowed down the structural determinants to the N terminus of β1, which contains two lysine residues (i.e., K3 and K4), which upon substitution virtually abolished the effects of β1 on charge movement. The mechanism by which K3 and K4 stabilize the voltage sensor is not electrostatic but specific, and the α (BK)-residues involved remain to be identified. This is the first report, to our knowledge, where the regulatory effects of the β1-subunit have been clearly assigned to a particular segment, with two pivotal amino acids being responsible for this modulation.

  17. Potassium conductances mediate bidirectional state-dependent modulation of action potential evoked dendritic calcium signals in dentate gyrus granule cells

    Directory of Open Access Journals (Sweden)

    János Brunner

    2014-03-01

    Full Text Available Backpropagating action potentials (bAPs and local calcium signals that they trigger are fundamental for dendritic functions. Here we addressed the question what extent the changes of local dendritic membrane properties can contribute to the shaping of the coupling between dendritic action potentials and the local calcium responses. Using a combination of in vitro electrophysiological and confocal imaging techniques we found that activation of dendritic GIRK channels via mGlu2 or GABAB receptors enhanced the bAP¬-triggered calcium signals in the dendrites of dentate gyrus granule cells (GCs. The enhancement of calcium signals was significant only in those dendritic regions, where these receptors are predominantly expressed. Similarly to GIRK channel activation, somatic hyperpolarization by DC current injection (from -64 mV to -77 mV, significantly increased bAP-associated calcium signals in the proximal dendrites. The hyperpolarization was associated with a decrease in the input resistance due to the rectification of the membrane potential of GCs. The effect of hyperpolarization on the calcium signals was maintained when T-type calcium currents were blocked but it decreased when GIRK channels were inhibited. Simultaneous dual somato-dendritic recordings from GCs showed that somatic hyperpolarization accelerated the repolarization phase of dendritic bAP in the proximal region whereas the rising phase and peak amplitude was not affected. We hypothesize that the larger driving force for calcium ions during the faster repolarization can contribute to the increasing in calcium signals. Employment of previously recorded dendritic bAP waveforms from hyperpolarized membrane potential as voltage command evoked larger calcium currents in nucleated patches compared to bAP waveform from the same recording at depolarized membrane potential. Furthermore, addition of native, high-voltage activated, inactivating potassium conductance by somatic dynamic clamp

  18. The slow calcium-dependent potassium current in a myenteric neurone of the guinea-pig ileum.

    Science.gov (United States)

    Hirst, G D; Johnson, S M; van Helden, D F

    1985-04-01

    Experiments were performed in current-clamped and voltage-clamped after-hyperpolarizing (AH) neurones of the guinea-pig myenteric plexus to examine the properties of the potassium conductance (gK, Ca) underlying the slow calcium-activated after-hyperpolarization (VK, Ca). The action potential plateau lengthened by the addition of tetraethylammonium chloride (TEA) to the bathing medium was compared to VK, Ca. Results were consistent with enhanced calcium entry causing an increase of VK, Ca. 4-Aminopyridine (4-AP) directly reduced VK, Ca. Voltage-clamp data of gK, Ca were well fitted by a process with a delay (approximately equal to 60 ms) followed by exponential activation (time constant approximately equal to 300 ms) and inactivation (time constant approximately equal to 2 s). The presence of a small, much slower inactivating process was noted. Values for time constants were similar to those reported by Morita, North & Tokimasa (1982) and North & Tokimasa (1983) where gK, Ca was measured during VK, Ca subsequent to action potential stimulation. The relation between gK, Ca (or the calcium-activated potassium current IK, Ca) and estimated calcium influx resulting from short-duration calcium currents elicited at various voltages was compared. Both the integral of the calcium current and gK, Ca showed a similar dependence on the depolarizations used to elicit IK, Ca except there was a positive shift of about 4 mV for the gK, Ca curve. This shift was attributed to a requirement for calcium ions to prime the gK, Ca mechanism. An inward ion charge movement of about 8 pC was required before significant activation of gK, Ca occurred. After the 'priming' condition had been established, the sensitivity of gK, Ca to inward calcium current measured at the resting potential was about 500 pS/pC of inward charge. Large calcium entry obtained by prolonged calcium currents caused saturation of the peak amplitude of IK, Ca and initiated currents with slower time to peak amplitude and

  19. Influence of calcium, magnesium, or potassium ions on the formation and stability of emulsions prepared using highly hydrolyzed whey proteins.

    Science.gov (United States)

    Ramkumar, C; Singh, H; Munro, P A; Singh, A M

    2000-05-01

    Oil-in-water emulsions (4 wt % soy oil) containing 4 wt % whey protein hydrolysate (WPH) (27% degree of hydrolysis) and different levels of calcium, magnesium, or potassium chloride were prepared in a two-stage homogenizer. Other emulsions containing 4 wt % WPH but including 0.35 wt % hydroxylated lecithin and different levels of the above minerals were similarly prepared. The formation and stability of these emulsions were determined by measuring oil droplet size distributions using laser light scattering and by confocal scanning laser microscopy and a gravity creaming test. Both lecithin-free and lecithin-containing emulsions showed no change in droplet size distributions with increasing concentration of potassium in the range 0-37.5 mM. In contrast, the diameter of emulsion droplets increased with increasing calcium or magnesium concentration >12.5 mM. Emulsions containing hydroxylated lecithin were more sensitive to the addition of calcium or magnesium than the lecithin-free emulsions. Storage of emulsions at 20 degrees C for 24 h further increased the diameter of droplets and resulted in extensive creaming in emulsions containing >25 mM calcium or magnesium. It appears that both flocculation and coalescence processes were involved in the destabilization of emulsions induced by the addition of divalent cations.

  20. Potassium current kinetics in bursting secretory neurons: effects of intracellular calcium.

    Science.gov (United States)

    Martínez, J J; Onetti, C G; García, E; Hernández, S

    1991-11-01

    1. The kinetics of delayed rectifier (IK) and transient potassium (IA) currents and their modification by intracellular calcium ions in bursting X-organ neurons of the crayfish were studied with whole-cell patch-clamp technique. Activation and inactivation kinetics were analyzed according to Hodgkin and Huxley-type equations. 2. IK activates with sigmoidal time course at membrane potentials more positive than -38.4 +/- 3.5 (SD) mV (n = 5), and does not inactivate. The conductance through delayed rectifier channels (gK) is described by the equation gK = GKn2. 3. IA activates at membrane potentials close to the resting potential (-52.2 +/- 4.3 mV, n = 5) and, after a peak, inactivates completely. The conductance through A-channels (gA) can be described by the product of independent activation and inactivation parameters: gA = GAa4b. Both activation and inactivation processes are voltage and time dependent. 4. Steady-state activation of IK and IA as well as inactivation of IA can be described by Boltzmann distributions for single particles with valencies of 2.55 +/- 0.01 (n = 5), 1.60 +/- 0.25 (n = 5), and 3.87 +/- 0.39 (n = 3), respectively. 5. Increasing [Ca2+]i, we observed the following: 1) a considerable inactivation of IK during test pulses, 2) an increase of maximal conductance for IA, 3) a reduction of the valency of IA inactivation gating particle (from 3.87 to 2.27), 4) a reduction of the inactivation time constants of IA, and 5) a shift of the inactivation steady-state curve to more positive membrane potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Tubocurarine blocks a calcium-dependent potassium current in rat tumoral pituitary cells.

    Science.gov (United States)

    Vacher, P; Vacher, A M; Mollard, P

    1998-04-30

    We investigated the effects of potassium channel inhibitors on electrical activity, membrane ionic currents, intracellular calcium concentration ([Ca2+]i) and hormone release in GH3/B6 cells (a line of pituitary origin). Patch-clamp recordings show a two-component after hyperpolarization (AHP) following each action potential (current clamp) or a two-component tail current (voltage-clamp). Both components can be blocked by inhibiting Ca2+ influx. Application of D-tubocurarine (dTc) (20-500 microM) reversibly suppressed the slowly decaying Ca2+-activated K+ tail current (I AHPs) in a concentration-dependent manner. On the other hand, low doses of tetraethylammonium ions (TEA+) only blocked the rapidly decaying voltage- and Ca2+-activated K+ tail current (I AHPf). Therefore, GH3/B6 cells exhibit at least two quite distinct Ca2+-dependent K+ currents, which differ in size, voltage- and Ca2+-sensitivity, kinetics and pharmacology. These two currents also play quite separate roles in shaping the action potential. d-tubocurarine increased spontaneous Ca2+ action potential firing, whereas TEA increased action potential duration. Thus, both agents stimulated Ca2+ entry. I AHPs is activated by a transient increase in [Ca2+]i such as a thyrotrophin releasing hormone-induced Ca2+ mobilization. All the K+ channel inhibitors we tested: TEA, apamin, dTC and charybdotoxin, stimulated prolactin and growth hormone release in GH3/B6 cells. Our results show that I AHPs is a good sensor for subplasmalemmal Ca2+ and that dTc is a good pharmacological tool for studying this current.

  2. Types of voltage—dependent calcium channels involved in high potassium depolarization—induced amylase secretion in the exocrine pancreatic tumour cell line AR4—2J

    Institute of Scientific and Technical Information of China (English)

    CUIZONGJIE

    1998-01-01

    In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium,Attached cells when stimulated with high potassium secreted large amount of amylase.High potassium-induced secretion was dependent both on the concentration of potassium and duration of stimulation.High potassium induced increases in intracellular calcium were inhibited by voltage-dependent calcium channel anatagonists with an order of potency as follows:nifedipine>ω-agatoxin IVA>ω-conotoxin GVIA.In contrast,the L-type calcium channel anatagonist nifedipine almost completely inhibited potassium-induced amylase secretion,whereas the N-type channel antagonist ω-conotoxin GVIA was without effect.The P-type channel antagonist ω-agatoxin IVA had a small inhibitory effect,but this inhibition was not significant at the level of amylase secretion.In conclusion,the AR4-2J cell line posesses different voltage-dependent calcium channels(L,P,N)with the L-type predominantly involved in depolarization induced amylase secretion.

  3. Soil chemical properties as affected by plant derived ash to replace potassium fertilizer and its conversion value

    Directory of Open Access Journals (Sweden)

    John Bako Baon

    2011-08-01

    Full Text Available Potassium chloride (KCl presently used as main source of K, tends to become more expensive, therefore, there is a need for a breakthrough in finding alternative materials to replace KCl. The aim of this paper is to present recent research on the use of plant derived ash to replace KCl fertilizer, especially in relation with soil chemical characteristics and its conversion value. Plant derived ash coming from palm sugar processing unit which use farm waste as main fuel was used in this experiment. Treatments investigated were no K2O application (control, applied with K2O in forms of both KCl and plant derived ash in dosages of 100, 200, 300, 400, 500 and 600 mg kg-1 air dry soil. The mixture of soil with those treatments were then incubated for one year. After incubation period, the soil in pots were divided into two parts, first part was added with 2g urea, while other part was added with 2 g SP 36. Both parts were incubated for two months. Results of this experiment showed that plant derived ash can be used to replaced KCl. To obtain similar soil K content, the amount of K2O in form of plant derived ash needed to be added or its conversion value is 1.44 times the amount of K2O in form of KCl. Use of plant derived ash also increased the content of soil Ca, available P, ratio of Ca/Mg and pH. Plant derived ash did not caused nitrogen loss. Key words: Potassium, fertilizer, plant derived ash, pH, soil.

  4. Bradykinin modulates potassium and calcium currents in neuroblastoma hybrid cells via different pertussis toxin-insensitive pathways.

    Science.gov (United States)

    Wilk-Blaszczak, M A; Gutowski, S; Sternweis, P C; Belardetti, F

    1994-01-01

    In NG108-15 cells, bradykinin (BK) activates a potassium current (IK,BK) and inhibits the voltage-dependent calcium current (ICa,V). BK also stimulates a phosphatidylinositol-specific phospholipase C (PI-PLC). The subsequent release of inositol 1,4,5-trisphosphate and increase in intracellular calcium contribute to IK,BK, through activation of a calcium-dependent potassium current. In membranes from these cells, stimulation of PI-PLC by BK is mediated by Gq and/or G11, two homologous, pertussis toxin-insensitive G proteins. Here, we have investigated the role of Gq/11 in the electrical responses to BK. GTP gamma S mimicked and occluded both actions of BK, and both effects were insensitive to pertussis toxin. Perfusion of an anti-Gq/11 alpha antibody into the pipette suppressed IK,BK, but not the inhibition of ICa,V by BK. Thus, BK couples to IK,BK via Gq/11, but coupling to ICa,V is most likely via a different, pertussis toxin-insensitive G protein.

  5. New precision mass measurements of neutron-rich calcium and potassium isotopes and three-nucleon forces

    CERN Document Server

    Gallant, A T; Brunner, T; Chowdhury, U; Ettenauer, S; Lennarz, A; Robertson, D; Simon, V V; Chaudhuri, A; Holt, J D; Kwiatkowski, A A; Mané, E; Menéndez, J; Schultz, B E; Simon, M C; Andreoiu, C; Delheij, P; Pearson, M R; Savajols, H; Schwenk, A; Dilling, J

    2012-01-01

    We present precision Penning-trap mass measurements of neutron-rich calcium and potassium isotopes in the vicinity of neutron number N=32. Using the TITAN system the mass of $^{51}$K was measured for the first time, and the precision of the $^{51,52}$Ca mass values were improved significantly. The new mass values show a dramatic increase of the binding energy compared to those reported in the atomic mass evaluation. In particular, $^{52}$Ca is more bound by 1.74 MeV, and the behavior with neutron number deviates substantially from the tabulated values. An increased binding was predicted recently based on calculations that include three-nucleon (3N) forces. We present a comparison to improved calculations, which agree remarkably with the evolution of masses with neutron number, making neutron-rich calcium isotopes an exciting region to probe 3N forces at neutron-rich extremes.

  6. Developmental mapping of small-conductance calcium-activated potassium channel expression in the rat nervous system.

    Science.gov (United States)

    Gymnopoulos, Marco; Cingolani, Lorenzo A; Pedarzani, Paola; Stocker, Martin

    2014-04-01

    Early electrical activity and calcium influx regulate crucial aspects of neuronal development. Small-conductance calcium-activated potassium (SK) channels regulate action potential firing and shape calcium influx through feedback regulation in mature neurons. These functions, observed in the adult nervous system, make them ideal candidates to regulate activity- and calcium-dependent processes in neurodevelopment. However, to date little is known about the onset of expression and regions expressing SK channel subunits in the embryonic and postnatal development of the central nervous system (CNS). To allow studies on the contribution of SK channels to different phases of development of single neurons and networks, we have performed a detailed in situ hybridization mapping study, providing comprehensive distribution profiles of all three SK subunits (SK1, SK2, and SK3) in the rat CNS during embryonic and postnatal development. SK channel transcripts are expressed at early stages of prenatal CNS development. The three SK channel subunits display different developmental expression gradients in distinct CNS regions, with time points of expression and up- or downregulation that can be associated with a range of diverse developmental events. Their early expression in embryonic development suggests an involvement of SK channels in the regulation of developmental processes. Additionally, this study shows how the postnatal ontogenetic patterns lead to the adult expression map for each SK channel subunit and how their coexpression in the same regions or neurons varies throughout development.

  7. An evaluation of in vitro intestinal absorption of iron, calcium and potassium in chickens receiving gold nanoparticles.

    Science.gov (United States)

    Sembratowicz, I; Ognik, K; Stępniowska, A

    2016-08-01

    This study evaluated the effect of oral administration of colloidal gold nanoparticles on accumulation of gold in the small intestine and intestinal absorption of iron, calcium and potassium under in vitro conditions. The gold nanoparticles are non-ionic, nanocrystalline, chemically pure particles 5 nm in size, produced in a physical process. In total, 126 one day-old Ross 308 chicks were assigned to 7 experimental groups of 18 birds each (3 replications of 6 individuals each). The control group (G-C) did not receive gold nanoparticles. Groups: Au-5(7), Au-10(7) and Au-15(7) received gold nanoparticles in their drinking water in the amounts of 5 mg l(-1) for group Au-5(7), 10 mg l(-1) for group Au-10(7) and 15 mg l(-1) for group Au-15(7) in 8-14, 22-28 and 36-42 d of life. The birds in groups Au-5(3), Au-10(3) and Au-15(3) received gold nanoparticles in the same amounts, but only in 8-10, 22-24 and 36-38 d of life. The study revealed that nanogold supplied via ingestion leads to dose- and time-dependent accumulation of gold in the intestinal walls. Nanogold present in the jejunum has a negative impact on the absorption of calcium, iron and potassium under in vitro conditions.

  8. Role of arachidonic acid in hyposmotic membrane stretch-induced increase in calcium-activated potassium currents in gastric myocytes

    Institute of Scientific and Technical Information of China (English)

    Meng YANG; Wen-xie XU; Xing-lan LI; Hui-ying XU; Jia-bin SUN; Bin MEI; Hai-feng ZHENG; Lian-hua PIAO; De-gang XING; Zhai-liu LI

    2005-01-01

    Aim: To study effects of arachidonic acid (AA) and its metabolites on the hyposmotic membrane stretch-induced increase in calcium-activated potassium currents (IKCa) in gastric myocytes. Methods: Membrane currents were recorded by using a conventional whole cell patch-clamp technique in gastric myocytes isolated with collagenase. Results: Hyposmotic membrane stretch and AA increased both IK(Ca) and spontaneous transient outward currents significantly.Exogenous AA could potentiate the hyposmotic membrane stretch-induced increase in IK(Ca). The hyposmotic membrane stretch-induced increase in IK(Ca) was significantly suppressed by dimethyleicosadienoic acid (100 μmol/L in pipette solution), an inhibitor of phospholipase A2. Nordihydroguaiaretic acid, a lipoxygenase inhibitor, significantly suppressed AA and hyposmotic membrane stretch-induced increases in IK(Ca). External calcium-free or gadolinium chloride, a blocker of stretch-activated channels, blocked the AA-induced increase in IK(Ca) significantly, but it was not blocked by nicardipine, an L-type calcium channel blocker. Ryanodine, a calcium-induced calcium release agonist, completely blocked the AA-induced increase in IK(Ca); however, heparin, a potent inhibitor of inositol triphosphate receptor, did not block the AA-induced increase in IK(Ca). Conclusion:Hyposmotic membrane stretch may activate phospholipase A2, which hydrolyzes membrane phospholipids to ultimately produce AA; AA as a second messenger mediates Ca2+ influx, which triggers Ca2+-induced Ca2+ release and elicits activation of IK(Ca) in gastric antral circular myocytes of the guinea pig.

  9. Role of calcium activated potassium channels in atrial fibrillation pathophysiology and therapy

    DEFF Research Database (Denmark)

    Diness, Jonas G.; Bentzen, Bo H.; S. Sørensen, Ulrik

    2015-01-01

    Small-conductance Ca2+-activated potassium (SK) channels are relative newcomers within the field of cardiac electrophysiology. In recent years, an increased focus has been given to these channels since they might constitute a relatively atrial selective target. The present review will give...

  10. Conservation of body calcium by increased dietary intake of potassium: A potential measure to reduce the osteoporosis process during prolonged exposure to microgravity

    Science.gov (United States)

    Nechay, Bohdan R.

    1989-01-01

    During the 1988 NASA Summer Faculty Fellowship Program, it was proposed that the loss of skeletal calcium upon prolonged exposure to microgravity could be explained, in part, by a renal maladjustment characterized by an increased urinary excretion of calcium. It was theorized that because the conservation of body fluids and electrolytes depends upon the energy of adenosine triphosphate and enzymes that control the use of its energy for renal ion transport, an induction of renal sodium and potassium-dependent adenosine triphosphatase (Na + K ATPase) by oral loading with potassium would increase the reabsorption of sodium directly and that of calcium indirectly, leading to improved hydration and to reduced calcium loss. Preliminary studies showed the following. Rats drinking water containing 0.2 M potassium chloride for six to 13 days excreted in urine 22 muEq of calcium and 135 muEq of sodium per 100 grams of body weight per day. The corresponding values for control rats drinking tap water were 43 muEq and 269 muEq respectively. Renal Na + K ATPase activity in potassium loaded rats was higher than in controls. Thus, oral potassium loading resulted in increased Na + K ATPase activity and diminished urinary excretion of calcium and of sodium as predicted by the hypothesis. An extension of these studies to humans has the potential of resulting in development of harmless, non-invasive, drug-free, convenient measures to reduce bone loss and other electrolyte and fluid problems in space travelers exposed to prolonged periods of microgravity.

  11. Quinine blocks a calcium-activated potassium conductance in mammalian enteric neurones.

    OpenAIRE

    Cherubini, E.; North, R. A.; Surprenant, A.

    1984-01-01

    Quinine (100 microM) abolished the slow calcium-dependent afterhyperpolarization which occurs after an action potential in some neurones of the guinea-pig myenteric and submucous plexus. This occurred without any effect on the amplitude or time course of the action potential itself, or on the faster calcium-independent afterhyperpolarization. Tetraethylammonium did not reduce the slow afterhyperpolarization. Quinine also abolished the hyperpolarization which was evoked by intracellular inject...

  12. A calcium-dependent potassium current is increased by a single-gene mutation in Paramecium.

    Science.gov (United States)

    Hennessey, T M; Kung, C

    1987-01-01

    The membrane currents of wild type Paramecium tetraurelia and the behavioral mutant teaA were analyzed under voltage clamp. The teaA mutant was shown to have a greatly increased outward current which was blocked completely by the combined use of internally delivered Cs+ and external TEA+. This, along with previous work (Satow, Y., Kung, C., 1976, J. Exp. Biol. 65:51-63) identified this as a K+ current. It was further found to be a calcium-activated K+ current since this increased outward K+ current cannot be elicited when the internal calcium is buffered with injected EGTA. The mutation pwB, which blocks the inward calcium current, also blocks this increased outward K+ current in teaA. This shows that this mutant current is activated by calcium through the normal depolarization-sensitive calcium channel. While tail current decay kinetic analysis showed that the apparent inactivation rates for this calcium-dependent K+ current are the same for mutant and wild type, the teaA current activates extremely rapidly. It is fully activated within 2 msec. This early activation of such a large outward current causes a characteristic reduction in the amplitude of the action potential of the teaA mutant. The teaA mutation had no effect on any of the other electrophysiological parameters examined. The phenotype of the teaA mutant is therefore a general decrease in responsiveness to depolarizing stimuli because of a rapidly activating calcium-dependent K+ current which prematurely repolarizes the action potential.

  13. Localization of large conductance calcium-activated potassium channels and their effect on calcitonin gene-related peptide release in the rat trigemino-neuronal pathway

    DEFF Research Database (Denmark)

    Wulf-Johansson, H.; Amrutkar, D.V.; Hay-Schmidt, Anders

    2010-01-01

    Large conductance calcium-activated potassium (BK(Ca)) channels are membrane proteins contributing to electrical propagation through neurons. Calcitonin gene-related peptide (CGRP) is a neuropeptide found in the trigeminovascular system (TGVS). Both BK(Ca) channels and CGRP are involved in migraine...

  14. Block by a putative antiarrhythmic agent of a calcium-dependent potassium channel in cultured hippocampal neurons.

    Science.gov (United States)

    McLarnon, J G

    1990-05-04

    The actions of a new, putative antiarrhythmic drug, KC-8851 on single channel currents in hippocampal CA1 neurons have been studied. A calcium-dependent potassium current IK(Ca) was activated in the cultured neurons when a solution containing 140 mM K+ and 0.2 mM Ca2+ was applied to inside-out patches. Addition of the compound KC-8851, at concentrations between 1-50 microM, resulted in significant, dose-dependent, decreases in the mean open times of the K channel. The onward (blocking) rate constant was determined from a simple channel blockade scheme and was 5 x 10(7) M-1s-1; this rate constant was not dependent on voltage. Addition of KC-8851 to the solution bath with outside-out patches also caused significant decreases in the mean open times of the IK(Ca) channel consistent with channel blockade by the drug.

  15. Whole-cell recordings of voltage-gated Calcium, Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    Shuyun Huang; Qing Cai; Weitian Liu; Xiaoling Wang; Tao Wang

    2009-01-01

    Objective:To record Calcium, Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons. Methods:Hip-pocampal CA3 neurons were freshly isolated by 1 mg protease/3 ml SES and mechanical trituration with polished pipettes of progressively smaller tip diameters. Patch clamp technique in whole-cell mode was employed to record voltage-gated channel currents. Results:The procedure dissociated hippocampal neurons, preserving apical dendrites and several basal dendrites, without impairing the electrical characteristics of the neurons. Whole-cell patch clamp configuration was successfully used to record voltage-gated Ca2+ currents, delayed rectifier K+ current and voltage-gated Na+ currents. Conclusion:Protease combined with mechanical trituration may be used for the dissociation of neurons from rat hippocampus. Voltage-gated channels currents could be recorded using a patch clamp technique.

  16. Evaluation of genotoxic effects of sodium propionate, calcium propionate and potassium propionate on the root meristem cells of Allium cepa.

    Science.gov (United States)

    Türkoğlu, Sifa

    2008-06-01

    The effects of different treatments with food preservatives, sodium propionate (SP), calcium propionate (CP) and potassium propionate (PP), on the cytology and DNA content of Allium cepa were investigated. Five concentrations of these additives - 1000, 1500, 2000, 2500, and 3000ppm - were applied for 24, 48, and 72h. All concentrations of these chemicals showed an inhibitory effect on cell division in root-tips of A. cepa and caused a decrease in mitotic index values. Additionally, all treatments changed the frequency of mitotic phases when compared with the control groups. These compounds increased chromosome abnormalities in test material. Among these abnormalities were C-mitosis, anaphase bridges, micronuclei, binucleated cells, stickiness, laggards, and chromosome breaks. The nuclear DNA contents decreased when compared with control groups.

  17. Dendrochemical patterns of calcium, zinc, and potassium related to internal factors detected by energy dispersive X-ray fluorescence (EDXRF)

    Science.gov (United States)

    Smith, Kevin T.; Balouet, Jean Christophe; Shortle, Walter C.; Chalot, Michel; Beaujard, François; Grudd, Håkan; Vroblesky, Don A.; Burkem, Joel G.

    2014-01-01

    Energy dispersive X-ray fluorescence (EDXRF) provides highly sensitive and precise spatial resolution of cation content in individual annual growth rings in trees. The sensitivity and precision have prompted successful applications to forensic dendrochemistry and the timing of environmental releases of contaminants. These applications have highlighted the need to distinguish dendrochemical effects of internal processes from environmental contamination. Calcium, potassium, and zinc are three marker cations that illustrate the influence of these processes. We found changes in cation chemistry in tree rings potentially due to biomineralization, development of cracks or checks, heartwood/sapwood differentiation, intra-annual processes, and compartmentalization of infection. Distinguishing internal from external processes that affect dendrochemistry will enhance the value of EDXRF for both physiological and forensic investigations.

  18. Mitochondrial calcium-activated potassium channel:another potential target for neuroprotection?

    Institute of Scientific and Technical Information of China (English)

    FangSHEN; Li-pingWU; QianSHEN; QiangXIA

    2004-01-01

    AIM: It has recently been reported that large-conductance Ca2+activated potassium channel is present in the inner mitochondrial membrane (mitoKCa) of the neuron cell, which has been reported to have cardioprotective effect similar to that of mitochondrial ATP-sensitive K+ channel (mitoKATP). Hence the aim of this study was to clarify if mitoKCa is neuroprotective and compare thisnotantial affect with that of mitoK METHODS: Male

  19. 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.

  20. Family-based randomized trial to detect effects on blood pressure of a salt substitute containing potassium and calcium in hypertensive adolescents.

    Science.gov (United States)

    Mu, Jianjun; Liu, Zhiquan; Liu, Fuqiang; Xu, Xianglin; Liang, Yimu; Zhu, Danjun

    2009-09-01

    Potassium and calcium are important in blood pressure (BP) regulation. The aim of this study was to test the effects on BP of adding potassium and calcium to dietary salt. A total of 325 adolescents selected with high BP (systolic BP (SBP) >or=90th percentile by age and sex) along with 978 family members. The adolescents were randomized into three groups by coin toss, and their families (300 total) were also allocated to the three groups: one in which 10 mmol of potassium and 10 mmol of calcium were added to the cooking salt, one encouraged to follow a salt-restricted diet, and a control group. In the salt-restricted group, salt intake was decreased gradually through health-behavior education to reach the goal of 50-100 mmol per person per day at 2 years. No intervention took place in for the control group. Salt sensitivity was determined by a volume expansion and contraction protocol at the beginning of the study. The three groups were followed up every 6 months for 2 years. At 2 years, systolic and diastolic blood pressure (SBP/DBP) had decreased by 5.9/2.8 mm Hg (4.7/3.6%) in the added-potassium-and-calcium group and by 5.8/1.0 mm Hg (4.8/1.4%) in the salt-restricted group; the values rose in the control group by 1.3/2.3 mm Hg (1.1/1.8%). There was no difference between the added-potassium-and-calcium group and the restricted-salt group (P = 0.24), but both differed significantly from the controls (P family members. Subgroup analysis showed that the BP in salt-sensitive (SS) subjects decreased more than in the non-salt-sensitive (NSS) group (P families in a that rural Chinese community.

  1. Comparative evaluation of a dentifrice containing calcium sodium phosphosilicate to a dentifrice containing potassium nitrate for dentinal hypersensitivity: A clinical study

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    Tanya Satyapal

    2014-01-01

    Full Text Available Background: Calcium sodium phosphosilicate is a recently introduced desensitizing agent which acts by occluding the dentinal tubules and also resists acid decalcification. This study was designed to assess the efficacy of a new toothpaste containing 5% calcium sodium phosphosilicate for the treatment of dentinal hypersensitivity and also compare it with 5% potassium nitrate. Materials and Methods: Sixty patients with the chief complaint of dentinal hypersensitivity were enrolled and randomly divided into two groups. The visual analog scale (VAS scores were taken for water and air stimuli at baseline, 3 weeks after usage of the respective toothpaste, and 3 weeks after discontinuation of the respective toothpaste. Results: Both the groups showed reduction in hypersensitivity scores at 3 weeks and 6 weeks for air stimulus and cold water. The calcium sodium phosphosilicate group, however, showed significantly reduction in hypersensitivity compared to the potassium nitrate group at any time point for both measures of hypersensitivity. Conclusion: The 5% calcium sodium phosphosilicate group showed immense reduction in dentinal hypersensitivity symptoms. The 5% calcium sodium phosphosilicate showed prolonged effects even after discontinuation as compared to 5% potassium nitrate, due to its dentinal tubular occlusion property.

  2. Voltage-gated potassium channel Kvl.3 in rabbit ciliary epithelium regulates the membrane potential via coupling intracellular calcium

    Institute of Scientific and Technical Information of China (English)

    LI Yan-feng; ZHUO Ye-hong; BI Wei-na; BAI Yu-jing; LI Yan-na; WANG Zhi-jian

    2008-01-01

    Background The cell layer of the ciliary epithelium is responsible for aqueous humor secretion and maintenance.Ion channels play an important role in these processes.The main aim of this study was to determine whether the well-characterized members of the Kvl family (Kv1.3) contribute to the Kv currents in ciliary epithelium.Methods New Zealand White rabbits were maintained in a 12 hours light/dark cycle.Ciliary epithelium samples were isolated from the rabbits.We used Western blotting and immunocytochemistry to identify the expression and location of a voltage-gated potassium channel Kvl.3 in ciliary body epithelium.Membrane potential change after adding of Kv1.3 inhibitor margatoxin (MgTX) was observed with a fluorescence method.Results Western blotting and immunocytochemical studies showed that the Kv1.3 protein expressed in pigment ciliary epithelium and nonpigment ciliary epithelium,however it seemed to express more in the apical membrane of the nonpigmented epithelial cells.One nmol/L margatoxin,a specific inhibitor of Kv1.3 channels caused depolarization of the cultured nonpigmented epithelium (NPE) membrane potential.The cytosotic calcium increased after NPE cell depolarization,this increase of cytosolic calcium was partially blocked by 12.5 μmol/L dantrolene and 10 μmol/L nifedipine.These observations suggest that Kv1.3 channels modulate ciliary epithelium potential and effect calcium dependent mechanisms.Conclusion Kv1.3 channels contribute to K+ efflux at the membrane of rabbit ciliary epithelium.

  3. Diffusion of sodium, potassium, calcium, manganese, and radon in tuff and clinoptilolite under leaching

    Science.gov (United States)

    Dikii, N. P.; Dovbnya, A. N.; Lyashko, Yu. V.; Medvedev, D. V.; Medvedeva, E. P.; Uvarov, V. L.; Achkasov, K. V.

    2011-07-01

    Nuclear physics methods are used to determine the diffusion coefficients of Na, Ca, Mn, K, and 222Rn in clinoptilolite (Sokirnitsa occurrence, Ukraine) and in natural tuff (Yucca Mountain, Nevada, United States) and in tuff irradiated by γ-quanta ( E max = 23 MeV) to a dose of 107 Gy at a leaching temperature of 37°C. The diffusion coefficients of sodium and potassium in clinoptilolite are found to differ considerably: 4 × 10-17 and 2 × 10-20 m2/s, respectively. This indicates the influence of aquacomplexes on the cation transfer. The diffusion coefficient of radon in these materials is determined: in clinoptilolite it equals 2.5 × 10-12 m2/s.

  4. Calcium-dependent modulation and plasma membrane targeting of the AKT2 potassium channel by the CBL4/ CIPK6 calcium sensor/protein kinase complex

    Institute of Scientific and Technical Information of China (English)

    Katrin Held; Jean-Baptiste Thibaud; J(o)rg Kudla; Francois Pascaud; Christian Eckert; Pawel Gajdanowicz; Kenji Hashimoto; Claire Corratgé-Faillie; Jan Niklas Offenborn; Beno(i)t Lacombe; Ingo Dreyer

    2011-01-01

    Potassium (K+) channel function is fundamental to many physiological processes. However, components and mechanisms regulating the activity of plant K+ channels remain poorly understood. Here, we show that the calcium (Ca2+)sensor CBL4 together with the interacting protein kinase CIPK6 modulates the activity and plasma membrane (PM)targeting of the K+ channel AKT2 from Arabidopsis thaliana by mediating translocation of AKT2 to the PM in plant cells and enhancing AKT2 activity in oocytes. Accordingly, akt2, cbl4 and cipk6 mutants share similar developmental and delayed flowering pheuotypes. Moreover, the isolated regulatory C-terminal domain of CIPK6 is sufficient for mediating CBL4- and Ca2+-dependent channel translocation from the endoplasmic reticulum membrane to the PM by a novel targeting pathway that is dependent on dual lipid modifications of CBL4 by myristoylation and palmitoylation. Thus, we describe a critical mechanism of ion-channel regulation where a Ca2+ sensor modulates K+ channel activity by promoting a kinase interaction-dependent but phosphorylation-independent translocation of the channel to the PM.

  5. Dietary potassium intake is beneficial to bone health in a low calcium intake population: the Korean National Health and Nutrition Examination Survey (KNHANES) (2008-2011).

    Science.gov (United States)

    Kong, S H; Kim, J H; Hong, A R; Lee, J H; Kim, S W; Shin, C S

    2017-05-01

    Dietary potassium may neutralize acid load and reduce calcium loss from the bone, leading to beneficial effect on bone mineral density. In this nationwide Korean population study, dietary potassium intake was associated with improved bone mineral density in older men and postmenopausal women. Nutrition is a major modifiable factor that affects bone health. The accompanying anion in dietary potassium may act as an alkaline source by neutralizing the acid load and reducing calcium loss from the bone. We aimed to evaluate the association between dietary potassium intake and bone mineral density (BMD) in the Korean population. We analyzed a total of 3135 men aged >50 years and 4052 postmenopausal women from the Korean National Health and Nutrition Examination Survey (KNHANES). Lumbar spine, total hip, and femur neck BMD were measured using dual energy X-ray absorptiometry. The daily food intake was assessed using a food frequency questionnaire. When we divided the participants into tertiles based on the intake of potassium intake, the highest potassium intake tertile group showed a significantly higher total hip and femur neck BMD as compared to lower tertile groups (0.914 ± 0.004, 0.928 ± 0.003, 0.925 ± 0.004 mg/day across the tertiles, P = .014 for total hip; 0.736 ± 0.003, 0.748 ± 0.003, 0.750 ± 0.004 mg/day, P = .012 for femur neck). Postmenopausal women in the highest potassium intake tertile group showed significantly higher lumbar, total hip, and femur neck BMD as compared to those in lower potassium intake tertile groups (0.793 ± 0.004, 0.793 ± 0.003, 0.805 ± 0.004 mg/day across the tertiles, P = .029 for lumbar spine; 0.766 ± 0.003, 0.770 ± 0.002, 0.780 ± 0.003 mg/day, P = .002 for total hip; 0.615 ± 0.003, 0.619 ± 0.002, 0.628 ± 0.003 mg/day, P = .002 for femur neck). Dietary potassium intake was positively associated with BMD in men aged >50 years and postmenopausal women, indicating the

  6. Statistical Analyses of Optimum Partial Replacement of Cement by Fly Ash Based on Complete Consumption of Calcium Hydroxide

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    Ouypornprasert Winai

    2016-01-01

    Full Text Available The objectives of this technical paper were to propose the optimum partial replacement of cement by fly ash based on the complete consumption of calcium hydroxide from hydration reactions of cement and the long-term strength activity index based on equivalent calcium silicate hydrate as well as the propagation of uncertainty due to randomness inherent in main chemical compositions in cement and fly ash. Firstly the hydration- and pozzolanic reactions as well as stoichiometry were reviewed. Then the optimum partial replacement of cement by fly ash was formulated. After that the propagation of uncertainty due to main chemical compositions in cement and fly ash was discussed and the reliability analyses for applying the suitable replacement were reviewed. Finally an applicability of the concepts mentioned above based on statistical data of materials available was demonstrated. The results from analyses were consistent with the testing results by other researchers. The results of this study provided guidelines of suitable utilization of fly ash for partial replacement of cement. It was interesting to note that these concepts could be extended to optimize partial replacement of cement by other types of pozzolan which were described in the other papers of the authors.

  7. Cyclic AMP enhances calcium-dependent potassium current in Aplysia neurons.

    Science.gov (United States)

    Ewald, D; Eckert, R

    1983-12-01

    The effect on the Ca-dependent potassium current, IK(Ca), of procedures that increase intracellular cAMP levels was studied in Aplysia neurons using three different pharmacological approaches. Exposure to cAMP analogues which were either resistant to or protected from phosphodiesterase hydrolysis caused an increase in IK(Ca) from 30 to 50% in 10 min. The degree of reversibility of this effect varied from complete with db cAMP to very little with pcpt cAMP. Exposure to cholera toxin, which stimulates the synthesis of endogenous cAMP, increased IK(Ca) 25% in 10 min and the effect was not reversible. Both approaches were effective in all seven neuron types studied. Application of serotonin plus phosphodiesterase inhibitor caused an increase in IK(Ca) in neuron R15 but not in the other neuron types. Application of pentylene tetrazole (PTZ) led to a decrease in IK(Ca). It is proposed that elevation of cyclic AMP mediates an increased sensitivity of the IK(Ca) channel to Ca ions.

  8. Replacement

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    S. Radhakrishnan

    2014-03-01

    Full Text Available The fishmeal replaced with Spirulina platensis, Chlorella vulgaris and Azolla pinnata and the formulated diet fed to Macrobrachium rosenbergii postlarvae to assess the enhancement ability of non-enzymatic antioxidants (vitamin C and E, enzymatic antioxidants (superoxide dismutase (SOD and catalase (CAT and lipid peroxidation (LPx were analysed. In the present study, the S. platensis, C. vulgaris and A. pinnata inclusion diet fed groups had significant (P < 0.05 improvement in the levels of vitamins C and E in the hepatopancreas and muscle tissue. Among all the diets, the replacement materials in 50% incorporated feed fed groups showed better performance when compared with the control group in non-enzymatic antioxidant activity. The 50% fishmeal replacement (best performance diet fed groups taken for enzymatic antioxidant study, in SOD, CAT and LPx showed no significant increases when compared with the control group. Hence, the present results revealed that the formulated feed enhanced the vitamins C and E, the result of decreased level of enzymatic antioxidants (SOD, CAT and LPx revealed that these feeds are non-toxic and do not produce any stress to postlarvae. These ingredients can be used as an alternative protein source for sustainable Macrobrachium culture.

  9. Two distinct pools of large-conductance calcium-activated potassium channels in the somatic plasma membrane of central principal neurons

    OpenAIRE

    Kaufmann, W.A.; Kasugai, Y.; Ferraguti, F.; Storm, J F

    2010-01-01

    Although nerve cell membranes are often assumed to be uniform with respect to electrical properties, there is increasing evidence for compartmentalization into subdomains with heterogeneous impacts on the overall cell function. Such microdomains are characterized by specific sets of proteins determining their functional properties. Recently, clustering of large-conductance calcium-activated potassium (BKCa) channels was shown at sites of subsurface membrane cisterns in cerebellar Purkinje cel...

  10. Stabilization/solidification of mercury-contaminated waste ash using calcium sodium phosphate (CNP) and magnesium potassium phosphate (MKP) processes.

    Science.gov (United States)

    Cho, Jae Han; Eom, Yujin; Lee, Tai Gyu

    2014-08-15

    This study examined the stabilization and solidification (S/S) of mercury (Hg)-contaminated waste ash generated from an industrial waste incinerator using chemically bonded phosphate ceramic (CBPC) technology. A magnesium potassium phosphate (MKP; MgKPO4 · 6H2O) ceramic, fabricated from MgO and KH2PO4, and a calcium sodium phosphate (CNP; CaNaPO4) ceramic, fabricated from CaO and Na2HPO4, were used as solidification binders in the CBPC process, and Na2S or FeS was added to each solidification binder to stabilize the Hg-contaminated waste ash. The S/S processes were conducted under various operating conditions (based on the solidification binder and stabilization reagent, stabilization reagent dosage, and waste loading ratio), and the performance characteristics of the S/S sample under each operating condition were compared, including the Hg leaching value and compressive strength. The Hg leaching value of untreated Hg-contaminated waste ash was 231.3 μg/L, whereas the S/S samples treated using the MKP and CNP processes exhibited Hg leaching values below the universal treatment standard (UTS) limit (25 μg/L). Although the compressive strengths of the S/S samples decreased as the sulfide dosage and waste loading ratio were increased, most of the S/S samples fabricated by the MKP and CNP processes exhibited good mechanical properties.

  11. Individual effects of sodium, potassium, calcium, and magnesium chloride salts on Lactobacillus pentosus and Saccharomyces cerevisiae growth.

    Science.gov (United States)

    Bautista-Gallego, J; Arroyo-López, F N; Durán-Quintana, M C; Garrido-Fernandez, A

    2008-07-01

    A quantitative investigation on the individual effects of sodium (NaCl), potassium (KCl), calcium (CaCl2), and magnesium (MgCl2) chloride salts against Lactobacillus pentosus and Saccharomyces cerevisiae, two representative microorganisms of table olives and other fermented vegetables, was carried out. In order to assess their potential activities, both the kinetic growth parameters and dose-response profiles in synthetic media (deMan Rogosa Sharpe broth medium and yeast-malt-peptone-glucose broth medium, respectively) were obtained and analyzed. Microbial growth was monitored via optical density measurements as a function of contact time in the presence of progressive chloride salt concentrations. Relative maximum specific growth rate and lag-phase period were modeled as a function of the chloride salt concentrations. Moreover, for each salt and microorganism tested, the noninhibitory concentrations and the MICs were estimated and compared. All chloride salts exerted a significant antimicrobial effect on the growth cycle; particularly, CaCl2 showed a similar effect to NaCl, while KCl and MgCl2 were progressively less inhibitory. Microbial susceptibility and resistance were found to be nonlinearly dose related.

  12. Steroid hormone regulation of the voltage-gated, calcium-activated potassium channel expression in developing muscular and neural systems.

    Science.gov (United States)

    Garrison, Sheldon L; Witten, Jane L

    2010-11-01

    A precise organization of gene expression is required for developing neural and muscular systems. Steroid hormones can control the expression of genes that are critical for development. In this study we test the hypothesis that the steroid hormone ecdysone regulates gene expression of the voltage-gated calcium-activated potassium ion channel, Slowpoke or KCNMA1. Late in adult development of the tobacco hawkmoth Manduca sexta, slowpoke (msslo) levels increased contributing to the maturation of the dorsal longitudinal flight muscles (DLMs) and CNS. We show that critical components of ecdysteroid gene regulation were present during upreglation of msslo in late adult DLM and CNS development. Ecdysteroid receptor complex heterodimeric partner proteins, the ecdysteroid receptor (EcR) and ultraspiracle (USP), and the ecdysone-induced early gene, msE75B, were expressed at key developmental time points, suggesting that ecdysteroids direct aspects of gene expression in the DLMs during these late developmental stages. We provide evidence that ecdysteroids suppress msslo transcription in the DLMs; when titers decline msslo transcript levels increase. These results are consistent with msslo being a downstream gene in an ecdysteroid-mediated gene cascade during DLM development. We also show that the ecdysteroids regulate msslo transcript levels in the developing CNS. These results will contribute to our understanding of how the spatiotemporal regulation of slowpoke transcription contributes to tailoring cell excitability to the differing physiological and behavioral demands during development.

  13. Bioefficacy of a novel calcium-potassium salt of (-)-hydroxycitric acid

    Energy Technology Data Exchange (ETDEWEB)

    Downs, Bernard W. [InterHealth Research Center, Benicia, CA (United States); Bagchi, Manashi [InterHealth Research Center, Benicia, CA (United States); Subbaraju, Gottumukkala V. [Laila Impex Research Center, Vijayawada (India); Shara, Michael A. [Department of Pharmacy Sciences, Creighton University Medical Center, 2500 California Plaza, Omaha, 68178 NE (United States); Preuss, Harry G. [Department of Physiology and Biophysics, Georgetown University Medical Center, Washington, DC (United States); Bagchi, Debasis [InterHealth Research Center, Benicia, CA (United States) and Department of Pharmacy Sciences, Creighton University Medical Center, 2500 California Plaza, Omaha, 68178 NE (United States)]. E-mail: debsis@creighton.edu

    2005-11-11

    Obesity is associated with cardiovascular disease, diabetes and certain forms of cancer. Popular strategies on weight loss often fail to address many key factors such as fat mass, muscle density, bone density, water mass, their inter-relationships and impact on energy production, body composition, and overall health and well-being. (-)-Hydroxycitric acid (HCA), a natural plant extract from the dried fruit rind of Garcinia cambogia, has been reported to promote body fat loss in humans without stimulating the central nervous system. The level of effectiveness of G. cambogia extract is typically attributed solely to HCA. However, other components by their presence or absence may significantly contribute to its therapeutic effectiveness. Typically, HCA used in dietary weight loss supplement is bound to calcium, which results in a poorly soluble (<50%) and less bioavailable form. Conversely, the structural characteristics of a novel Ca{sup 2+}/K{sup +} bound (-)-HCA salt (HCA-SX or Super CitriMax) make it completely water soluble as well as bioavailable. An efficacious dosage of HCA-SX (4500 mg/day t.i.d.) provides a good source of Ca{sup 2+} (495 mg, 49.5% of RDI) and K{sup +} (720 mg, 15% of RDI). Ca{sup 2+} ions are involved in weight management by increasing lipid metabolism, enhancing thermogenesis, and increasing bone density. K{sup +}, on the other hand, increases energy, reduces hypertension, increases muscle strength and regulates arrhythmias. Both Ca and K act as buffers in pH homeostasis. HCA-SX has been shown to increase serotonin availability, reduce appetite, increase fat oxidation, improve blood lipid levels, reduce body weight, and modulate a number of obesity regulatory genes without affecting the mitochondrial and nuclear proteins required for normal biochemical and physiological functions.

  14. Calcium-activated potassium current modulates ventricular repolarization in chronic heart failure.

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    Ingrid M Bonilla

    Full Text Available The role of I(KCa in cardiac repolarization remains controversial and varies across species. The relevance of the current as a therapeutic target is therefore undefined. We examined the cellular electrophysiologic effects of I(KCa blockade in controls, chronic heart failure (HF and HF with sustained atrial fibrillation. We used perforated patch action potential recordings to maintain intrinsic calcium cycling. The I(KCa blocker (apamin 100 nM was used to examine the role of the current in atrial and ventricular myocytes. A canine tachypacing induced model of HF (1 and 4 months, n = 5 per group was used, and compared to a group of 4 month HF with 6 weeks of superimposed atrial fibrillation (n = 7. A group of age-matched canine controls were used (n = 8. Human atrial and ventricular myocytes were isolated from explanted end-stage failing hearts which were obtained from transplant recipients, and studied in parallel. Atrial myocyte action potentials were unchanged by I(KCa blockade in all of the groups studied. I(KCa blockade did not affect ventricular myocyte repolarization in controls. HF caused prolongation of ventricular myocyte action potential repolarization. I(KCa blockade caused further prolongation of ventricular repolarization in HF and also caused repolarization instability and early afterdepolarizations. SK2 and SK3 expression in the atria and SK3 in the ventricle were increased in canine heart failure. We conclude that during HF, I(KCa blockade in ventricular myocytes results in cellular arrhythmias. Furthermore, our data suggest an important role for I(KCa in the maintenance of ventricular repolarization stability during chronic heart failure. Our findings suggest that novel antiarrhythmic therapies should have safety and efficacy evaluated in both atria and ventricles.

  15. Action of niflumic acid on evoked and spontaneous calcium-activated chloride and potassium currents in smooth muscle cells from rabbit portal vein.

    Science.gov (United States)

    Hogg, R. C.; Wang, Q.; Large, W. A.

    1994-01-01

    1. The action of niflumic acid was studied on spontaneous and evoked calcium-activated chloride (ICl(Ca)) and potassium (IK(Ca)) currents in rabbit isolated portal vein cells. 2. With the nystatin perforated patch technique in potassium-containing solutions at a holding potential of -77 mV (the potassium equilibrium potential), niflumic acid produced a concentration-dependent inhibition of spontaneous transient inward current (STIC, calcium-activated chloride current) amplitude. The concentration to reduce the STIC amplitude by 50% (IC50) was 3.6 x 10(-6) M. 3. At -77 mV holding potential, niflumic acid converted the STIC decay from a single exponential to 2 exponential components. In niflumic acid the fast component of decay was faster, and the slow component was slower than the control decay time constant. Increasing the concentration of niflumic acid enhanced the decay rate of the fast component and reduced the decay rate of the slow component. 4. The effect of niflumic acid on STIC amplitude was voltage-dependent and at -50 and +50 mV the IC50 values were 2.3 x 10(-6) M and 1.1 x 10(-6) M respectively (cf. 3.6 x 10(-6) M at -77 mV). 5. In K-free solutions at potentials of -50 mV and +50 mV, niflumic acid did not induce a dual exponential STIC decay but just increased the decay time constant at both potentials in a concentration-dependent manner. 6. Niflumic acid, in concentrations up to 5 x 10(-5) M, had no effect on spontaneous calcium-activated potassium currents.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7921628

  16. Role of calcium-activated potassium currents in CNP-induced relaxation of gastric antral circular smooth muscle in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Hui-Shu Guo; Zheng-Xu Cai; Hai-Feng Zheng; Xiang-Lan Li; Yi-Feng Cui; Zuo-Yu Wang; Wen-Xie Xu; Sang-Jin Lee; Young-Chul Kim

    2003-01-01

    AIM: To investigate ion channel mechanism in CNP-induced relaxation of gastric circular smooth muscle in guinea pigs.METHODS: Spontaneous contraction of gastric smooth muscle was recorded by a four -channel physiograph. The whole cell patch-clamp technique was used to record calciumactivated potassium currents and membrane potential in the gastric myocytes isolated by collagenase.RESULTS: C-type natriuretic peptide (CNP) markedly inhibited the spontaneous contraction in a dose-dependent manner in gastric circular smooth muscle in guinea pigs.Ly83583, an inhibitor of guanylate cyclase, weakened CNPinduced inhibition on spontaneous contraction but Zaparinast, an inhibitor of cGMP sensitive phosphoesterase,potentiated CNP-induced inhibition in gastric circular smooth muscles. The inhibitory effects of CNP on spontaneous contraction were blocked by tetrathylammonium (TEA), a nonselective potassium channel blocker. CNP hyperpolarized membrane potential from -60.0 mV±2.0 mV to -68.3 meV±3.0 mV in a single gastric myocyte. CNP increased calcium-activated potassium currents (Ik(ca)) in a dose-dependent manner in gastric circular myocytes. CNP also increased the spontaneously transient outward currents (STOCs). Ly83583 partly blocked CNP-induced increase of calcium-activated potassium currents, but Zaparinast potented the effect.CONCLUSION: CNP inhibits spontaneous contraction, and potassium channel may be involved in the process in gastric circular smooth musde of guinea pigs. CNP-induced increase of Ik(ca) is mediated by a cGMP dependent pathway.

  17. Transient calcium-dependent potassium current in magnocellular neurosecretory cells of the rat supraoptic nucleus.

    Science.gov (United States)

    Bourque, C W

    1988-03-01

    1. Magnocellular neurosecretory neurones were impaled in the supraoptic nucleus of perfused explants of rat hypothalamus. Membrane currents were studied at 35 degrees C using the single-microelectrode voltage-clamp technique. 2. Depolarizing voltage steps applied from -100 mV evoked a transient outward current (TOC) from a threshold of -75 mV. From this potential, the amplitude of the current increased non-linearly with voltage. 3. Following its activation TOC reached a peak within 7 ms and subsequently decayed monotonically with a time constant of 30 ms. This time constant did not vary significantly with voltage between -75 and -55 mV. 4. The TOC showed complete steady-state inactivation at potentials positive to -55 mV. Inactivation was removed by hyperpolarization, with a mid-point near -80 mV. The removal of inactivation followed a complex time course with distinct fast (tens of milliseconds) and slow (hundreds of milliseconds) components. 5. Tail current measurements revealed that the TOC equilibrium potential (ETOC) lies near -97 mV in the presence of 3 mM [K+]o. Increasing [K+]o caused a decrease of TOC amplitude and a shift in ETOC of 57 mV/log [K+]o. The TOC is therefore predominantly a K+ current. 6. The TOC was unaffected by tetraethylammonium (up to 12 mM) but was reversibly reduced by 4-aminopyridine (ca. 50% block at 1.0 mM) and dendrotoxin (ca. 50% block at 4 nM). 7. The TOC was strongly inhibited (greater than 70%) by adding Co2+ or Mn2+ (1-3 mM) or Cd2+ (50-400 microM) to Ca-containing solutions, or by removal of Ca2+ from the perfusate. These effects were not accompanied by detectable changes in threshold voltage. The amplitude of TOC was also depressed by the organic Ca2+ channel blocker methoxyverapamil (D600). Finally replacement of Ca2+ by Ba2+ in the perfusate completely and reversibly abolished the TOC. 8. These findings suggest that neurosecretory neurones of the rat supraoptic nucleus display a transient K+ current which is strongly

  18. Partial replacement of sodium chloride by potassium chloride in the formulation of French bread: effect on the physical, physicochemical and sensory parameters

    Directory of Open Access Journals (Sweden)

    Thaisa Abrantes Souza GUSMÃO

    Full Text Available Abstract This study aimed to the replacement of sodium chloride (0.4 to 1.6% by potassium chloride (0.2 to 0.8% in French bread formulation and evaluate its effect on physical, physicochemical and sensory characteristics. For the preparation of bread was used a factorial design 22 with 4 factorial points and 3 central points, totaling 7 experiments. The physical and physicochemical parameters analyzed were: specific volume, moisture, color of the peel and crumb, pH, acidity and texture profile, sodium and potassium. The sensory evaluation of bread was performed using quantitative descriptive analysis, with 12 sensory terminologies. Response variables of salty taste and sensory chewiness generated statistically significant models. The results indicated optimal ranges of 0.2 to 0.5% of potassium chloride, and 1.0 to 1.6% for sodium chloride, and proved the technical feasibility of producing French bread with 50% salt reduction (174.09 mg.50 g–1, compared to a standard formulation of 1.88% (306.5 mg.50g-1 salt, corresponding to the prognosis recommended by the National Health Surveillance Agency.

  19. Effects of unsaturated fatty acids on calcium-activated potassium current in gastric myocytes of guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Hai-Feng Zheng; Xiang-Lan Li; Zheng-Yuan Jin; Jia-Bin Sun; Zai-Liu Li; Wen-Xie Xu

    2005-01-01

    AIM: To investigate the effects of exogenous unsaturated fatty acids on calcium-activated potassium current [Ik(Ca)]in gastric antral circular myocytes of guinea pigs.METHODS: Gastric myocytes were isolated by collagenase from the antral circular layer of guinea pig stomach. The whole-cell patch clamp technique was used to record Ik(Ca)in the isolated single smooth muscle cells with or without different concentrations of arachidonic acid (AA), linoleic acid (LA), and oleic acid (OA).RESULTS: AA at concentrations of 2,5 and 10 μmol/L markedly increased IK(ca)in a dose-dependent manner. LA at concentrations of 5, 10 and 20 μmol/L also enhanced IK(Ca)in a dose-dependent manner. The increasing potency of AA, LA, and oleic acid (OA) on Ik(Ca) at the same concentration(10 μmol/L) was in the order of AA>LA>OA. AA (10 μmol/L)-induced increase of Ik(Ca) was not blocked by H-7 (10 μmol/L), an inhibitor of protein kinase C (PKC), or indomethacin (10 μmol/L),an inhibitor of the cyclooxygenase pathway, and 17-octadecynoic acid (10 μmol/L), an inhibitor of the cytochrome P450 pathway, but weakened by nordihydroguaiaretic acid(10 μmol/L), an inhibitor of the lipoxygenase pathway.CONCLUSION: Unsaturated fatty acids markedly increase Ik(Ca), and the enhancing potencies are related to the number of double bonds in the fatty acid chain. The lipoxygenase pathway of unsaturated fatty acid metabolism is involved in the unsaturated fatty acid-induced increase of IK(Ca) in gastric antral circular myocytes of guinea pigs.

  20. Chronic fluoxetine treatment increases NO bioavailability and calcium-sensitive potassium channels activation in rat mesenteric resistance arteries.

    Science.gov (United States)

    Pereira, Camila A; Ferreira, Nathanne S; Mestriner, Fabiola L; Antunes-Rodrigues, José; Evora, Paulo R B; Resstel, Leonardo B M; Carneiro, Fernando S; Tostes, Rita C

    2015-10-15

    Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), has effects beyond its antidepressant properties, altering, e.g., mechanisms involved in blood pressure and vasomotor tone control. Although many studies have addressed the acute impact of fluoxetine on the cardiovascular system, there is a paucity of information on the chronic vascular effects of this SSRI. We tested the hypothesis that chronic fluoxetine treatment enhances the vascular reactivity to vasodilator stimuli by increasing nitric oxide (NO) signaling and activation of potassium (K+) channels. Wistar rats were divided into two groups: (I) vehicle (water for 21 days) or (II) chronic fluoxetine (10 mg/kg/day in the drinking water for 21 days). Fluoxetine treatment increased endothelium-dependent and independent vasorelaxation (analyzed by mesenteric resistance arteries reactivity) as well as constitutive NO synthase (NOS) activity, phosphorylation of eNOS at Serine1177 and NO production, determined by western blot and fluorescence. On the other hand, fluoxetine treatment did not alter vascular expression of neuronal and inducible NOS or guanylyl cyclase (GC). Arteries from fluoxetine-treated rats exhibited increased relaxation to pinacidil. Increased acetylcholine vasorelaxation was abolished by a calcium-activated K+ channel (KCa) blocker, but not by an inhibitor of KATP channels. On the other hand, vascular responses to Bay 41-2272 and 8-bromo-cGMP were similar between the groups. In conclusion, chronic fluoxetine treatment increases endothelium-dependent and independent relaxation of mesenteric resistance arteries by mechanisms that involve increased eNOS activity, NO generation, and KCa channels activation. These effects may contribute to the cardiovascular effects associated with chronic fluoxetine treatment.

  1. S-acylation dependent post-translational cross-talk regulates large conductance calcium- and voltage- activated potassium (BK channels

    Directory of Open Access Journals (Sweden)

    Michael J Shipston

    2014-08-01

    Full Text Available Mechanisms that control surface expression and/or activity of large conductance calcium-activated potassium (BK channels are important determinants of their (pathophysiological function. Indeed, BK channel dysfunction is associated with major human disorders ranging from epilepsy to hypertension and obesity. S-acylation (S-palmitoylation represents a major reversible, post-translational modification controlling the properties and function of many proteins including ion channels. Recent evidence reveals that both pore-forming and regulatory subunits of BK channels are S-acylated and control channel trafficking and regulation by AGC-family protein kinases. The pore-forming α-subunit is S-acylated at two distinct sites within the N- and C-terminus, each site being regulated by different palmitoyl acyl transferases (zDHHCs and acyl thioesterases. (APTs. S-acylation of the N-terminus controls channel trafficking and surface expression whereas S-acylation of the C-terminal domain determines regulation of channel activity by AGC-family protein kinases. S-acylation of the regulatory β4-subunit controls ER exit and surface expression of BK channels but does not affect ion channel kinetics at the plasma membrane. Furthermore, a significant number of previously identified BK-channel interacting proteins have been shown, or are predicted to be, S-acylated. Thus, the BK channel multi-molecular signalling complex may be dynamically regulated by this fundamental post-translational modification and thus S-acylation likely represents an important determinant of BK channel physiology in health and disease.

  2. Effects of Ginkgolide B on action potential and calcium,potassium current in guinea pig ventricular myocytes

    Institute of Scientific and Technical Information of China (English)

    Xiao-yan QI; Zhi-xiong ZHANG; You-qiu XU

    2004-01-01

    AIM: To investigate the effect of Ginkgolide B (GB) on action potential (AP), delayed rectifier potassium current (IK), and L-type calcium current (ICa-L) in guinea pig ventricular myocytes. METHODS: Single ventricular myocytes were isolated by an enzymatic dissociation method. AP, IK, ICa-L were recorded by whole-cell patch-clamp technique in either current or voltage clamp mode. RESULTS: GB shortened APD in a concentration-dependent manner. GB 0.1, 1, and 10 μmol/L shortened APD50 by 7.9 % (n=5, P>0.05), 18.4 % (n=5, P<0.01), and 28.9 % (n=6, P<0.01), respectively; APD90 by 12.4 % (n=5, P>0.05), 17.6 % (n=5, P<0.01), 26.4 % (n=5, P<0.01),respectively. GB increased IK in a concentration-dependent manner. GB 0.1, 1, and l0 μmol/L increased IK by 20.1% (n=6, P<0.05), 43.1% (n=6, P<0.01), 55.6 % (n=6, P<0.05); increased IKtail by 10.7 % (n=6, P<0.05),25.1% (n=6, P<0.05), and 37.7 % (n=6, P<0.05), respectively at testing potential of +50 mV and shift the I-V curve of Ik upward. But GB had no significant effect on ICa-L at above concentrations. CONCLUSION: GB significantly shortened APD in a concentration-dependent manner which mainly due to increase of IK.

  3. Extract from leaf of Psidium guajava L depresses the guinea pig atrial contractility by interfering with potassium and calcium channels

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    Antonio Nei Santana Gondim

    2009-09-01

    Full Text Available The negative inotropic effect of aqueous fraction (AqF obtained from the acetic extract of Psidium guajava L leaf was investigated on the guinea pig left atrium. Myocardial force was measured isometrically (27 ± 0.1 ºC, 2 Hz. AqF (100 μg/ml reduced contractility of about 85 ± 9.4 % (n = 4, p 0.05 sugesting that the oxide nitric pathway did not participate of the action mechanism of AqF. We can conclude that AqF depresses the atrial contractile by reducing the calcium entry in myocardial cells and also by openenig potassium channels of cardiac tissue.O efeito inotrópico da fração aquosa (AqF do extrato acético das folhas de Psidium guajava L. foi investigado em átrio esquerdo de cobaia. A força miocárdica foi medida isometricamente (27 ± 0,1 ºC; 2 Hz. A AqF (100 μg/mL reduziu a contratilidade em até 85 ± 9,4 % (n = 4; p 0,05, sugerindo que a via do óxido nítrico não participa do mecanismo de ação da AqF. Conclui-se que a AqF deprime a contratilidade atrial por reduzir a entrada de cálcio nas células miocárdicas e por abrir canais de potássio deste tecido.

  4. Expression of the calcium-activated potassium channel in upper and lower segment human myometrium during pregnancy and parturition

    Science.gov (United States)

    Gao, Lu; Cong, Binghai; Zhang, Lanmei; Ni, Xin

    2009-01-01

    Background Large conductance calcium-activated potassium channel (BKCa) plays an important role in the control of uterine contractility during pregnancy. The change from uterine quiescence to enhanced contractile activity may be associated with the spatial and temporal expression of BKCa within myometrium. The objectives of this study were to examine the expression of BKCa alpha- and beta-subunit in upper segment (US) and lower segment (LS) regions of uterus, and to investigate for the possibly differential expression of these proteins in US and LS myometrium obtained from three functional states: (1) non-pregnant (NP); (2) term pregnant not in labour (TNL) and (3) term pregnant in labour (TL). Methods Myometrial biopsies were collected from non-pregnant women at hysterectomy and pregnant women at either elective caesarean section or emergency caesarean section. Protein expression level and cellular localization of BKCa alpha- and beta-subunit in US and LS myometrium were determined by Western blot analysis and immunohistochemistry, respectively. Results BKCa alpha- and beta-subunit were predominantly localized to myometrial smooth muscle in both US and LS myometrium obtained from non-pregnant and pregnant patients. The level of BKCa alpha-subunit in US but not in LS was significantly higher in NP myometrium than those measured in myometrium obtained during pregnancy. Lower expression of BKCa alpha-subunit in both US and LS was found in TL than in TNL biopsies. Expression of beta-subunit in both US and LS myometrium was significantly reduced in TL group compared with those measured in TNL group. There was no significant difference in BKCa beta-subunit expression in either US or LS between NP and TNL group. Conclusion Our results suggest that expression of BKCa alpha- and beta-subunit in pregnant myometrium is reduced during labour, which is consistent with the myometrial activity at the onset of parturition. PMID:19344525

  5. Expression of the calcium-activated potassium channel in upper and lower segment human myometrium during pregnancy and parturition

    Directory of Open Access Journals (Sweden)

    Zhang Lanmei

    2009-04-01

    Full Text Available Abstract Background Large conductance calcium-activated potassium channel (BKCa plays an important role in the control of uterine contractility during pregnancy. The change from uterine quiescence to enhanced contractile activity may be associated with the spatial and temporal expression of BKCa within myometrium. The objectives of this study were to examine the expression of BKCa alpha- and beta-subunit in upper segment (US and lower segment (LS regions of uterus, and to investigate for the possibly differential expression of these proteins in US and LS myometrium obtained from three functional states: (1 non-pregnant (NP; (2 term pregnant not in labour (TNL and (3 term pregnant in labour (TL. Methods Myometrial biopsies were collected from non-pregnant women at hysterectomy and pregnant women at either elective caesarean section or emergency caesarean section. Protein expression level and cellular localization of BKCa alpha- and beta-subunit in US and LS myometrium were determined by Western blot analysis and immunohistochemistry, respectively. Results BKCa alpha- and beta-subunit were predominantly localized to myometrial smooth muscle in both US and LS myometrium obtained from non-pregnant and pregnant patients. The level of BKCa alpha-subunit in US but not in LS was significantly higher in NP myometrium than those measured in myometrium obtained during pregnancy. Lower expression of BKCa alpha-subunit in both US and LS was found in TL than in TNL biopsies. Expression of beta-subunit in both US and LS myometrium was significantly reduced in TL group compared with those measured in TNL group. There was no significant difference in BKCa beta-subunit expression in either US or LS between NP and TNL group. Conclusion Our results suggest that expression of BKCa alpha- and beta-subunit in pregnant myometrium is reduced during labour, which is consistent with the myometrial activity at the onset of parturition.

  6. Calcium-activated potassium channels mediated blood-brain tumor barrier opening in a rat metastatic brain tumor model

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    Ong John M

    2007-03-01

    Full Text Available Abstract Background The blood-brain tumor barrier (BTB impedes the delivery of therapeutic agents to brain tumors. While adequate delivery of drugs occurs in systemic tumors, the BTB limits delivery of anti-tumor agents into brain metastases. Results In this study, we examined the function and regulation of calcium-activated potassium (KCa channels in a rat metastatic brain tumor model. We showed that intravenous infusion of NS1619, a KCa channel agonist, and bradykinin selectively enhanced BTB permeability in brain tumors, but not in normal brain. Iberiotoxin, a KCa channel antagonist, significantly attenuated NS1619-induced BTB permeability increase. We found KCa channels and bradykinin type 2 receptors (B2R expressed in cultured human metastatic brain tumor cells (CRL-5904, non-small cell lung cancer, metastasized to brain, human brain microvessel endothelial cells (HBMEC and human lung cancer brain metastasis tissues. Potentiometric assays demonstrated the activity of KCa channels in metastatic brain tumor cells and HBMEC. Furthermore, we detected higher expression of KCa channels in the metastatic brain tumor tissue and tumor capillary endothelia as compared to normal brain tissue. Co-culture of metastatic brain tumor cells and brain microvessel endothelial cells showed an upregulation of KCa channels, which may contribute to the overexpression of KCa channels in tumor microvessels and selectivity of BTB opening. Conclusion These findings suggest that KCa channels in metastatic brain tumors may serve as an effective target for biochemical modulation of BTB permeability to enhance selective delivery of chemotherapeutic drugs to metastatic brain tumors.

  7. CNTF-Treated Astrocyte Conditioned Medium Enhances Large-Conductance Calcium-Activated Potassium Channel Activity in Rat Cortical Neurons.

    Science.gov (United States)

    Sun, Meiqun; Liu, Hongli; Xu, Huanbai; Wang, Hongtao; Wang, Xiaojing

    2016-08-01

    Seizure activity is linked to astrocyte activation as well as dysfunctional cortical neuron excitability produced from changes in calcium-activated potassium (KCa) channel function. Ciliary neurotrophic factor-treated astrocyte conditioned medium (CNTF-ACM) can be used to investigate the peripheral effects of activated astrocytes upon cortical neurons. However, CNTF-ACM's effect upon KCa channel activity in cultured cortical neurons has not yet been investigated. Whole-cell patch clamp recordings were performed in rat cortical neurons to evaluate CNTF-ACM's effects upon charybdotoxin-sensitive large-conductance KCa (BK) channel currents and apamin-sensitive small-conductance KCa (SK) channel current. Biotinylation and RT-PCR were applied to assess CNTF-ACM's effects upon the protein and mRNA expression, respectively, of the SK channel subunits SK2 and SK3 and the BK channel subunits BKα1 and BKβ3. An anti-fibroblast growth factor-2 (FGF-2) monoclonal neutralizing antibody was used to assess the effects of the FGF-2 component of CNTF-ACM. CNTF-ACM significantly increased KCa channel current density, which was predominantly attributable to gains in BK channel activity (p ACM produced a significant increase in BKα1 and BKβ3 expression (p  0.05). Blocking FGF-2 produced significant reductions in KCa channel current density (p > 0.05) as well as BKα1 and BKβ3 expression in CNTF-ACM-treated neurons (p > 0.05). CNTF-ACM significantly enhances BK channel activity in rat cortical neurons and that FGF-2 is partially responsible for these effects. CNTF-induced astrocyte activation results in secretion of neuroactive factors which may affect neuronal excitability and resultant seizure activity in mammalian cortical neurons.

  8. Genetic control and transgressive segregation of zinc, iron, potassium, phosphorus, calcium, and sodium accumulation in cowpea (Vigna unguiculata) seeds.

    Science.gov (United States)

    Fernandes Santos, C A; Boiteux, L S

    2015-01-16

    Cowpea crop, through combining a range of essential minerals with high quality proteins, plays an important role in providing nutritional security to human population living in semi-arid regions. Studies on genetics of biofortification with essential minerals are still quite scarce, and the major objective of the present study was to provide genetic information on development of cowpea cultivars with high seed mineral contents. Genetic parameters heritability and minimum number of genes were estimated for seed accumulation of zinc (Zn), iron (Fe), calcium (Ca), phosphorus (P), potassium (K), and sodium (Na). Generation mean and variance analyses were conducted using contrasting parental lines, F₁, F₂, and backcross populations derived from IT97K-1042-3 x BRS Tapaihum and IT97K-1042-3 x Canapu crosses. High narrow-sense heritability (h²) values were found for accumulation of Fe (65-86%), P (74-77%), and K (77-88%), whereas moderate h(2) values were observed for accumulation of Ca (41-56%), Zn (51-83%), and Na (50-55%) in seeds. Significant additive genetic effects as well as parental mean effects were detected in both crosses for all minerals, whereas epistasis was important genetic component in Zn content. The minimum number of genes controlling the accumulation of minerals ranged from two (K) to 11 (P). Transgressive segregation was observed in F2 populations of both crosses for all minerals analyzed. The results suggest that, although under either oligogenic or polygenic control, the seed content of these six minerals in cowpea can be improved via standard breeding methods largely used for self-pollinated crops.

  9. Calcium-dependent potassium channels as a target protein for modulation of the blood-brain tumor barrier.

    Science.gov (United States)

    Ningaraj, Nagendra S; Rao, Mamatha; Black, Keith L

    2003-06-01

    Even though the blood-brain tumor barrier (BTB) is more permeable than the blood-brain barrier (BBB), the BTB still significantly restricts the delivery of anticancer drugs to brain tumors. Brain tumor capillaries that form the BTB, however, express certain unique protein markers that are absent or barely detectable in normal brain capillaries. We were able to biochemically modulate one such protein marker, the calcium-dependent potassium (K(Ca)) channel, by using a specific K(Ca) channel agonist, NS-1619, to obtain sustained enhancement of selective drug delivery, including molecules of varying sizes, to tumors in rat syngeneic and xenograft brain tumor models. Immunolocalization and potentiometric studies showed increased K(Ca) channel distribution on tumor cells compared with normal cells, suggesting that tumor cell-specific signals might induce overexpression of K(Ca) channels in capillary endothelial cells, leading to increased BTB permeability. We also demonstrated that the cellular mechanism for K(Ca) channel-mediated BTB permeability increase is due to accelerated formation of pinocytotic vesicles, which can transport therapeutic molecules across the BTB. This concept was investigated by using NS-1619 to facilitate increased delivery of carboplatin to brain tumor leading to enhanced survival in rats with brain tumors. Additionally, we showed that K(Ca) channel modulation resulted in enhanced permeability to macromolecules, including Her-2 monoclonal antibody and green fluorescent protein-adenoviral vectors, in a human, primary brain-tumor xenograft model. Therefore, K(Ca) channels are a potential, promising target for biochemical modulation of BTB permeability to increase antineoplastic drug delivery selectively to brain tumors.

  10. Potassium bicarbonate supplementation lowers bone turnover and calcium excretion in older men and women a randomized dose-finding trial

    Science.gov (United States)

    The acid load accompanying modern diets may have adverse effects on bone and muscle metabolism. Treatment with alkaline salts of potassium can neutralize the acid load, but the optimal amount of alkali is not established. Our objective was to determine the effectiveness of two doses of potassium bic...

  11. Production of potassium Sulfate by Liquid-phase catalysis Method from Calcium Sulfate and potassium chloride%液相催化下硫酸钙制取硫酸钾的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘慧君

    2001-01-01

    文章通过对K2+2、Ca2+∥Cl2-2、SO2-4——H2O四元交互水盐体系相图分析,确定硫酸钙与氯化钾在36%氨浓度条件下液相催化生成硫酸钾,其K+转化率为78.8%,SO2-4析出率为88.6%。%By K2-2,Ca2+∥Cl-22,SO2-4——H2O quadruple cross hydrous salt system phase diagram analysis, under 36% ammonia water condition,potassium sulfate is produced from calcium sulfate and potassium chloride by liquid-phase catalysis. The potassium ion conversion rate can be controlled as 78.8%. Sulfate precipitation rate can be controlled as 88.6%.

  12. Feasibility and antihypertensive effect of replacing regular salt with mineral salt -rich in magnesium and potassium- in subjects with mildly elevated blood pressure

    Directory of Open Access Journals (Sweden)

    Sarkkinen Essi S

    2011-09-01

    Full Text Available Abstract Background High salt intake is linked to hypertension whereas a restriction of dietary salt lowers blood pressure (BP. Substituting potassium and/or magnesium salts for sodium chloride (NaCl may enhance the feasibility of salt restriction and lower blood pressure beyond the sodium reduction alone. The aim of this study was to determine the feasibility and effect on blood pressure of replacing NaCl (Regular salt with a novel mineral salt [50% sodium chloride and rich in potassium chloride (25%, magnesium ammonium potassium chloride, hydrate (25%] (Smart Salt. Methods A randomized, double-blind, placebo-controlled study was conducted with an intervention period of 8-weeks in subjects (n = 45 with systolic (SBP 130-159 mmHg and/or diastolic (DBP 85-99 mmHg. During the intervention period, subjects consumed processed foods salted with either NaCl or Smart Salt. The primary endpoint was the change in SBP. Secondary endpoints were changes in DBP, daily urine excretion of sodium (24-h dU-Na, potassium (dU-K and magnesium (dU-Mg. Results 24-h dU-Na decreased significantly in the Smart Salt group (-29.8 mmol; p = 0.012 and remained unchanged in the control group: resulting in a 3.3 g difference in NaCl intake between the groups. Replacement of NaCl with Smart Salt resulted in a significant reduction in SBP over 8 weeks (-7.5 mmHg; p = 0.016. SBP increased (+3.8 mmHg, p = 0.072 slightly in the Regular salt group. The difference in the change of SBP between study groups was significant (p Conclusions The substitution of Smart Salt for Regular salt in subjects with high normal or mildly elevated BP resulted in a significant reduction in their daily sodium intake as well as a reduction in SBP. Trial Registration ISRCTN: ISRCTN01739816

  13. [The characteristics and oxidative modulation of large-conductance calcium-activated potassium channels in guinea-pig colon smooth muscle cells.].

    Science.gov (United States)

    Huang, Wei-Feng; Ouyang, Shou; Zhang, Hui

    2009-06-25

    To investigate the characteristics of large-conductance calcium-activated potassium channels (BK(Ca)) and the effect of hydrogen peroxide (H2O2) on BK(Ca) in guinea-pig proximal colon smooth muscle cells, single smooth muscle cells of guinea-pig colon were enzymatically isolated in low calcium solution containing papain (3 mg/mL), DTT (2 mg/mL), and bovine serum albumin (BSA, 2 mg/mL). Tissues were incubated at 36 degrees C in enzyme solution for 15 min and were then suspended in enzyme-free low calcium solution. Inside-out single channel recording technique was used to record BK(Ca) current. The intracellular (bath) and microelectrode solution both contained symmetrical high potassium. The BK(Ca) in guinea-pig colon smooth muscle cell possesses: 1) voltage-dependence, 2) high selectivity for potassium ion, 3) large conductance (223.7 pS+/-9.2 pS), 4) dependence of [Ca(2+)](i). Intracellular application of H2O2 decreased the open probability (P(o)) of BK(Ca) at low concentration (Ca) at high concentration (5 mmol/L), without affecting the unitary conductance. The effects of H2O2 were reversed by reducing agent dithiothreitol (DTT). Similarly, cysteine specific oxidizing agent, DTNB, also increased or decreased P(o) of BK(Ca) and DTT partially reversed the effect of DTNB. It is thus suggested that H2O2 and DTNB may modulate P(o) of BK(Ca) via the oxidation of cysteine residue.

  14. Calcium-dependent potassium channels play a critical role for burst termination in the locomotor network in lamprey.

    Science.gov (United States)

    el Manira, A; Tegnér, J; Grillner, S

    1994-10-01

    1. The possible involvement of calcium-dependent potassium channels (KCa) in the termination of locomotor bursts was investigated by administration of a specific blocker, apamin, in the lamprey spinal cord in vitro. The effects were examined by recording the efferent activity in ventral roots and by intracellular recording from interneurons and motoneurons. During fictive locomotion induced by N-methyl-D-aspartate (NMDA), apamin was found to affect both the frequency of bursting and the regularity of the locomotor pattern. 2. At the single cell level, NMDA can induce pacemaker-like membrane potential oscillations in individual neurons after administration of tetrodotoxin. Apamin (2.5 microM) produced a marked increase of the duration of the depolarizing plateau phase occurring during these NMDA-induced oscillations; this shows that the repolarization of the plateau is initiated by a progressive activation of apamin-sensitive KCa-channels. 3. The action potential is followed by an afterhyperpolarization (AHP) with a fast and a slow phase (sAHP). The latter is known to be caused by apamin-sensitive KCa-channels. During repetitive firing, the interspike interval is dependent on the amplitude and the duration of the sAHP. Apamin caused a reduction of the spike frequency adaptation with a concomitant increase in the firing frequency. In some cells, apamin in addition reduced the threshold for the action potential. Apamin-sensitive KCa-channels thus will be involved in controlling both the onset and the duration of neuronal firing in the lamprey spinal cord. 4. During fictive locomotion induced by NMDA (40-200 microM), a blockade of KCa-channels by apamin produced an increase of the coefficient of variation (mean = 167%, n = 26), which was statistically significant in 21 out of 26 experiments. At 40-150 microM NMDA, an average increase in cycle duration was 77% and statistically significant in 15 out of 20 preparations. At 200 microM NMDA (corresponding to higher burst

  15. Long-term effects of imidapril on calcium and potassium currents in rabbit left ventricular hypertrophic myocytes

    Institute of Scientific and Technical Information of China (English)

    李泱; 陆再英; 肖建民; 张存泰; 马杰; 刘念

    2003-01-01

    Objective To investigate the long-term effects of imidapril (IMI) on action potential and calcium and potassium currents in rabbit left ventricular hypertrophic myocytes.Methods Rabbits were randomly divided into three groups: IMI-treated, hypertrophic and sham-operated control groups. Cardiac hypertrophy was induced in hypertrophy group by partial ligation of the abdominal aorta. In the IMI-treated group, the rabbits were administered IMI (1.5 mg·kg-1·d-1) for 8 weeks after surgery. In the sham-operated control group, the animals underwent an abdominal laparotomy without further procedure. Whole-cell patch clamp technique was used to record ionic currents.Results Membrane capacitance was larger in hypertrophic cells than in sham-operated cells or IMI-treated cells. Action potential duration was lengthened in hypertrophic cells and was remarkably shortened by IMI. The density of ICa,L was reduced from 12.8±0.7 pA/pF in the sham-operated cells, to 7.7±0.8 pA/pF in hypertrophic cells, while it resembled the control cells after IMI treatment (11.9±1.0 pA/pF). After IMI treatment, the density of IKs,tail was enhanced from 2.5±0.1 pA/pF in hypertrophic cells to 4.7±0.6 pA/pF (n=7, P<0.01), which was similar to the sham-operated cells. The densities of Ito and IK1 were significantly increased in IMI-treated cells, from 3.8±0.4 pA/pF and 3.7±0.5 pA/pF in the hypertrophic cells to 6.4±0.8 pA/pF and 6.5±0.3 pA/pF, respectively, but the IKr densities were not different in the three groups.Conclusion IMI could reverse the increase in membrane capacitance in hypertrophic cells, shorten action potential duration, and increase the densities of ICa, L, IKs, Ito and IK1 in hypertrophic cells.

  16. Effect of Calcium and Potassium on Antioxidant System of Vicia faba L. Under Cadmium Stress

    Directory of Open Access Journals (Sweden)

    Hayssam M. Ali

    2012-05-01

    Full Text Available Cadmium (Cd in soil poses a major threat to plant growth and productivity. In the present experiment, we studied the effect of calcium (Ca2+ and/or potassium (K+ on the antioxidant system, accumulation of proline (Pro, malondialdehyde (MDA, and content of photosynthetic pigments, cadmium (Cd and nutrients, i.e., Ca2+ and K+ in leaf of Vicia faba L. (cv. TARA under Cd stress. Plants grown in the presence of Cd exhibited reduced growth traits [root length (RL plant−1, shoot length (SL plant−1, root fresh weight (RFW plant−1, shoot fresh weight (SFW plant−1, root dry weight (RDW plant−1 and shoot dry weight (SDW plant−1] and concentration of Ca2+, K+, Chlorophyll (Chl a and Chl b content, except content of MDA, Cd and (Pro. The antioxidant enzymes [peroxidase (POD and superoxide dismutase (SOD] slightly increased as compared to control under Cd stress. However, a significant improvement was observed in all growth traits and content of Ca2+, K+, Chl a, Chl b ,Pro and activity of antioxidant enzymes catalase (CAT, POD and SOD in plants subjected to Ca2+ and/or K+. The maximum alleviating effect was recorded in the plants grown in medium containing Ca2+ and K+ together. This study indicates that the application of Ca2+ and/or K+ had a significant and synergistic effect on plant growth. Also, application of Ca2+ and/or K+ was highly effective against the toxicity of Cd by improving activity of antioxidant enzymes and solute that led to the enhanced plant growth of faba bean plants.

  17. Pass the Rock: calcium, the achilles heel of transcatheter valve replacement.

    Science.gov (United States)

    McCabe, James M; Dean, Larry S

    2017-01-01

    Increasing annular calcification portends more adverse outcomes and worse hemodynamic results following percutaneous structural heart interventions. Though the Direct Flow prosthesis did not appear to have significantly different post-procedural gradients based on aortic valve calcium burden in a selected group of patients, the average residual gradients were relatively high in all cases and the presence of a paravalvular leak was more common with increasing valvular calcification. It is unclear how the Direct Flow prosthesis fits into the armamentarium of TAVR prostheses.

  18. Calcium

    Science.gov (United States)

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

  19. Calcium-activated potassium channel SK1 is widely expressed in the peripheral nervous system and sensory organs of adult zebrafish.

    Science.gov (United States)

    Cabo, R; Zichichi, R; Viña, E; Guerrera, M C; Vázquez, G; García-Suárez, O; Vega, J A; Germanà, A

    2013-10-25

    Sensory cells contain ion channels involved in the organ-specific transduction mechanisms that convert different types of stimuli into electric energy. Here we focus on small-conductance calcium-activated potassium channel 1 (SK1) which plays an important role in all excitable cells acting as feedback regulators in after-hyperpolarization. This study was undertaken to analyze the pattern of expression of SK1 in the zebrafish peripheral nervous system and sensory organs using RT-PRC, Westernblot and immunohistochemistry. Expression of SK1 mRNA was observed at all developmental stages analyzed (from 10 to 100 days post fertilization, dpf), and the antibody used identified a protein with a molecular weight of 70kDa, at 100dpf (regarded to be adult). Cell expressing SK1 in adult animals were neurons of dorsal root and cranial nerve sensory ganglia, sympathetic neurons, sensory cells in neuromasts of the lateral line system and taste buds, crypt olfactory neurons and photoreceptors. Present results report for the first time the expression and the distribution of SK1 in the peripheral nervous system and sensory organs of adult zebrafish, and may contribute to set zebrafish as an interesting experimental model for calcium-activated potassium channels research. Moreover these findings are of potential interest because the potential role of SK as targets for the treatment of neurological diseases and sensory disorders.

  20. Will mineral trioxide aggregate replace calcium hydroxide in treating pulpal and periodontal healing complications subsequent to dental trauma?

    DEFF Research Database (Denmark)

    Bakland, Leif K; Andreasen, Jens O

    2012-01-01

    Mineral trioxide aggregate (MTA) has over the last two decades begun to take the place of calcium hydroxide (CH) in the treatment of a variety of pulpal and periodontal healing complications following dental trauma. These conditions include teeth with: (i) exposed pulps, (ii) immature roots...... and pulp necrosis, (iii) root fractures and pulp necrosis located in the coronal part of the pulps, and (iv) external infection-related (inflammatory) root resorption. The main reasons for replacing CH with MTA in these situations have generally been the delayed effect when using CH to induce hard tissues......, the quality of such induced hard tissues, and finally the dentin weakening effect of CH, which in some instances lead to cervical root fractures in immature teeth. MTA appears, from a relatively few clinical studies, to overcome these shortcomings of CH. The lack of long-term clinical studies, however, may...

  1. Fat digestion in veal calves fed milk replacers low or high in calcium and containing either casein or soy protein isolate.

    Science.gov (United States)

    Yuangklang, C; Wensing, Th; Van den Broek, L; Jittakhot, S; Beynen, A C

    2004-04-01

    The hypothesis tested was that the inhibitory effect of dietary soy protein versus casein on fat digestion in veal calves would be smaller when diets were fed with high instead of low calcium content. Male calves, 1 wk of age, were fed 1 of 4 experimental milk replacers in a 2 x 2 factorial design. There were 19 animals per dietary group. The milk replacers contained either casein or soy protein isolate as variable protein source and were either low or high in calcium. Body weight gain was not significantly affected by the experimental diets. Soy protein isolate versus casein significantly reduced apparent fat digestibility. High versus low calcium intake also depressed fat digestion. The protein effect was smaller (2.9% units) for the high than the low calcium diets (3.6% units), but the interaction did not reach statistical significance. Soy protein isolate versus casein raised fecal bile acid excretion and so did high versus low calcium intake. The difference in bile acid excretion between the soy and casein containing diets was significantly greater for the high than low calcium diets. The absorption of phosphorus, calcium, and magnesium was higher for the casein diets than for the soy-containing diets. This study shows for the first time that soy protein isolate versus casein depressed fat digestion and raised fecal bile acid excretion in veal calves.

  2. Will mineral trioxide aggregate replace calcium hydroxide in treating pulpal and periodontal healing complications subsequent to dental trauma? A review.

    Science.gov (United States)

    Bakland, Leif K; Andreasen, Jens O

    2012-02-01

    Mineral trioxide aggregate (MTA) has over the last two decades begun to take the place of calcium hydroxide (CH) in the treatment of a variety of pulpal and periodontal healing complications following dental trauma. These conditions include teeth with: (i) exposed pulps, (ii) immature roots and pulp necrosis, (iii) root fractures and pulp necrosis located in the coronal part of the pulps, and (iv) external infection-related (inflammatory) root resorption. The main reasons for replacing CH with MTA in these situations have generally been the delayed effect when using CH to induce hard tissues, the quality of such induced hard tissues, and finally the dentin weakening effect of CH, which in some instances lead to cervical root fractures in immature teeth. MTA appears, from a relatively few clinical studies, to overcome these shortcomings of CH. The lack of long-term clinical studies, however, may warrant a certain reservation in an unrestricted replacement of CH with MTA. A definite need for randomized clinical studies comparing CH and MTA in trauma healing situations is urgently needed.

  3. Study of granitic biotites by X-ray fluorescence analysis: determination of iron, manganese, titanium, calcium, potassium, silicon and aluminium; Estudio de biotitas graniticas por fluorescencia de rayos X: Determinacion de hierro, manganeso, titanio, calcio, potasio, silicio y aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Toubes, R. O.; Bermudez Polonio, J.

    1968-07-01

    A method for the quantitative determination of iron, manganese, titanium, calcium potassium, silicon, and aluminium, is reported, Sample preparation is carried out by the miniature flux technique, and rubidium is used as internal standard for silicon and aluminium. (Author) 5 refs.

  4. Activation of endothelial and epithelial KCa2.3 calcium-activated potassium channels by NS309 relaxes human small pulmonary arteries and bronchioles

    DEFF Research Database (Denmark)

    Kroigaard, Christel; Dalsgaard, Thomas; Nielsen, Gorm

    2012-01-01

    BACKGROUND AND PURPOSE: Small (K(Ca) 2) and intermediate (K(Ca) 3.1) conductance calcium-activated potassium channels (K(Ca) ) may contribute to both epithelium- and endothelium-dependent relaxations, but this has not been established in human pulmonary arteries and bronchioles. Therefore, we...... investigated the expression of K(Ca) 2.3 and K(Ca) 3.1 channels, and hypothesized that activation of these channels would produce relaxation of human bronchioles and pulmonary arteries. EXPERIMENTAL APPROACH: Channel expression and functional studies were conducted in human isolated small pulmonary arteries.......1 activator, NS309, induced concentration-dependent relaxations. NS309 was equally potent in relaxing pulmonary arteries, but less potent in bronchioles, than salbutamol. NS309 relaxations were blocked by the K(Ca) 2 channel blocker apamin, while the K(Ca) 3.1 channel blocker, charybdotoxin failed to reduce...

  5. Computational approaches to understand the adverse drug effect on potassium, sodium and calcium channels for predicting TdP cardiac arrhythmias.

    Science.gov (United States)

    Sharifi, Mohsen

    2017-09-01

    Ion channels play a crucial role in the cardiovascular system. Our understanding of cardiac ion channel function has improved since their first discoveries. The flow of potassium, sodium and calcium ions across cardiomyocytes is vital for regular cardiac rhythm. Blockage of these channels, delays cardiac repolarization or tend to shorten repolarization and may induce arrhythmia. Detection of drug risk by channel blockade is considered essential for drug regulators. Advanced computational models can be used as an early screen for torsadogenic potential in drug candidates. New drug candidates that are determined to not cause blockage are more likely to pass successfully through preclinical trials and not be withdrawn later from the marketplace by manufacturer. Several different approved drugs, however, can cause a distinctive polymorphic ventricular arrhythmia known as torsade de pointes (TdP), which may lead to sudden death. The objective of the present study is to review the mechanisms and computational models used to assess the risk that a drug may TdP. There is strong evidence from multiple studies that blockage of the L-type calcium current reduces risk of TdP. Blockage of sodium channels slows cardiac action potential conduction, however, not all sodium channel blocking antiarrhythmic drugs produce a significant effect, while late sodium channel block reduces TdP. Interestingly, there are some drugs that block the hERG potassium channel and therefore cause QT prolongation, but they are not associated with TdP. Recent studies confirmed the necessity of studying multiple distinctionic ion channels which are responsible for cardiac related diseases or TdP, to obtain an improved clinical TdP risk prediction of compound interactions and also for designing drugs. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Structural and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from alite hydration in the presence of sodium and potassium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, Oscar, E-mail: oamendoz@unal.edu.co [Grupo del Cemento y Materiales de Construcción (CEMATCO). Universidad Nacional de Colombia, Facultad de Minas, Medellín (Colombia); Giraldo, Carolina [Cementos Argos S.A., Medellín (Colombia); Camargo, Sergio S. [Engenharia Metalúrgica e de Materiais, Universidade Federal do Rio de Janeiro/COPPE, Rio de Janeiro (Brazil); Tobón, Jorge I. [Grupo del Cemento y Materiales de Construcción (CEMATCO). Universidad Nacional de Colombia, Facultad de Minas, Medellín (Colombia)

    2015-08-15

    This research evaluates the effect of sodium and potassium hydroxide on the structure and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from the hydration of pure alite. Monoclinic (MIII) alite was synthesized and hydrated, using water-to-alite ratios of 0.5 and 0.6 and additions of 10% NaOH and KOH by weight of alite. Based on results of X-ray diffraction, isothermal calorimetry, thermogravimetric analysis, Nuclear Magnetic Resonance and nanoindentation, two different effects of the alkaline hydroxides on the hydration reaction of alite, both at early and later ages, can be identified: (i) a differentiated hydration process, attributed to an enhancement in calcium hydroxide (CH) precipitation and a stimulation of the C-S-H nuclei; and (ii) an increase in the elastic modulus of the C-S-H aggregations, attributed to an electrostatic attraction between positive charges from the alkaline cations and negative charges from the C-S-H structure.

  7. Functional coupling between large-conductance potassium channels and Cav3.2 voltage-dependent calcium channels participates in prostate cancer cell growth

    Directory of Open Access Journals (Sweden)

    Florian Gackière

    2013-07-01

    It is strongly suspected that potassium (K+ channels are involved in various aspects of prostate cancer development, such as cell growth. However, the molecular nature of those K+ channels implicated in prostate cancer cell proliferation and the mechanisms through which they control proliferation are still unknown. This study uses pharmacological, biophysical and molecular approaches to show that the main voltage-dependent K+ current in prostate cancer LNCaP cells is carried by large-conductance BK channels. Indeed, most of the voltage-dependent current was inhibited by inhibitors of BK channels (paxillin and iberiotoxin and by siRNA targeting BK channels. In addition, we reveal that BK channels constitute the main K+ channel family involved in setting the resting membrane potential in LNCaP cells at around −40 mV. This consequently promotes a constitutive calcium entry through T-type Cav3.2 calcium channels. We demonstrate, using single-channel recording, confocal imaging and co-immunoprecipitation approaches, that both channels form macromolecular complexes. Finally, using flow cytometry cell cycle measurements, cell survival assays and Ki67 immunofluorescent staining, we show that both BK and Cav3.2 channels participate in the proliferation of prostate cancer cells.

  8. Potassium-induced contraction in the lamb proximal urethra: Involvement of norepinephrine and different calcium entry pathways

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Pascual, A.; Costa, G.; Isla, M.; Jimenez, E.; Garcia-Sacristan, A. (Universidad Complutense de Madrid (Spain))

    1991-01-01

    The purpose of this work was to investigate the mechanisms involved in the peculiar biphasic response of the lamb urethral smooth muscle to high K+ solutions. The relative amplitude of the phasic and tonic components of the contraction and its reproducibility were dependent on the concentration of K+ used. Only concentrations higher than 80 mM (i.e., 120 mM) showed a tonic component greater in amplitude than the phasic one and manifested a tachyphylactic effect. Phentolamine (10(-6) M), prazosin (10(-6) M) and chemical denervation with 6-hydroxydopamine significantly inhibited the tonic component of the K+ (120 mM)-induced contraction, modifying its morphology. Reproducible contractions to K+ (120 mM) could be obtained in the presence of prazosin (10(-6) M) or cocaine (10(-6) M). The preparations were also shown to accumulate (3H)noradrenaline and release it upon depolarization with K+ (60 and 120 mM). Calcium removal inhibited the K+ (120 mM)-induced contraction. After addition of calcium (0.5-5 mM) the contractile activity was restored. Nifedipine (10(-6) M) and verapamil (10(-6) M) but not sodium nitroprusside (10(-6) M) significantly blocked the contractile response for calcium as well as the phasic component of the K+ contraction in calcium-containing medium. In preparations treated with prazosin (10(-6) M) the tonic component of the K+ (120 mM) contraction was more sensitive to nifedipine and removal of extracellular calcium than the phasic one.

  9. The utilization of rock phosphate (natural defluorinated calcium phosphate or NDCP in laying hens diet to replace dicalcium phosphate

    Directory of Open Access Journals (Sweden)

    A.P Sinurat

    1996-06-01

    Full Text Available An experimentwas conducted to study the utilization of local rock phosphate or natural defluorinated calcium phosphate (NDCP as phosphorus source for layer chickens by using the imported dicalcium phosphate (DCP as a reference. Eight experimental diets consisted of 2 source of phosphorus (DCP and NDCP and 4 dietary total P levels (0.4, 0.5, 0.6 and 0.7% were formulated. Each diet was fed to 24 pullets (6 replicates with 4 birds each from 20 weeks of age to 14 weeks of egg production. Observations were made on feed consumption, egg production, egg weight, mortality, egg quality, Ca and P retention and ash content of tibial bones . Results showed no significant effect of different source and level of phosphorus tested on egg production (% HD, feed consumption, egg weight and mortality rates . Egg shell thickness was depressed in NDCP diet as compared with DCP, however this only occurred at firstmonth of production. It is concluded that the NDCP can be used in layers diet to replace DCP as phosphorus source. The relative biological value of phosphorus inNDCP is 96% for layers.

  10. 78 FR 63228 - Determination That Potassium Citrate, 10 Milliequivalents/Packet and 20 Milliequivalents/Packet...

    Science.gov (United States)

    2013-10-23

    ... management of renal tubular acidosis with calcium stones, hypocitraturic calcium oxalate nephrolithiasis of any etiology, and uric acid lithiasis with or without calcium stones. Potassium Citrate, 10...

  11. Study and Test of Process of Production of Potassium Chloride from High Calcium Potassium Bearing Brine in Salt Lake%利用盐湖高钙含钾卤水制取氯化钾工艺试验研究

    Institute of Scientific and Technical Information of China (English)

    朱晓东; 郑秀洁

    2011-01-01

    In some of chloride - type brine in Salt Lake of Qinghai. The cycling accumulation of calcium results in increasing growth of its concetration, which probably will make some effect on the production of potassium chloride from brine. This paper makes research on impact this type of high calcium potassium bearing brine has on production of potassium chloride by 4# Process . The research results show that calcium content in brine would have less impact on production of potassium chloride by 4# Process.%青海盐湖部分氯化物型卤水中,由于钙的循环积累,其浓度不断增高,这可能对从卤水中提取氯化钾带来一定影响.实验研究了该类型高钙含钾卤水对4#工艺制取氯化钾的影响,研究结果表明卤水中钙含量对4#工艺制取氯化钾影响较小.

  12. Investigations on the crystal-structure and non-ambient behaviour of K2Ca2Si8O19 - a new potassium calcium silicate

    Science.gov (United States)

    Schmidmair, Daniela; Kahlenberg, Volker; Praxmarer, Alessandra; Perfler, Lukas; Mair, Philipp

    2017-09-01

    Within the context of a systematic re-investigation of phase relationships between compounds of the ternary system K2O-CaO-SiO2 a new potassium calcium silicate with the chemical formula K2Ca2Si8O19 was synthesized via solid state reactions as well as the flux method using KCl as a solvent. Its crystal structure was determined from single-crystal X-ray diffraction data by applying direct methods. The new compound crystallizes in the triclinic space group P 1 bar . Unit cell dimensions are a = 7.4231(7) Å, b = 10.7649(10) Å, c = 12.1252(10) Å, α = 70.193(8)°, β = 83.914(7)° and γ = 88.683(7)°. K2Ca2Si8O19 is built up of corner-connected, slightly distorted [SiO4]-tetrahedra forming double-sheets, which are linked by double-chains of edge-sharing [CaO6]-octahedra. Electroneutrality of the material is provided by additional potassium atoms that are located within the voids of the silicate layers and between adjacent [Ca2O6]-double-chains. Further characterization of the compound was performed by Raman spectroscopy and differential thermal analysis. The behaviour of K2Ca2Si8O19 under high-temperature and high-pressure was investigated by in-situ high-temperature powder X-ray diffraction up to a maximum temperature of 1125 °C and a piston cylinder experiment at 1.5 GPa and 1100 °C. Additionally an overview of known double-layer silicates is given as well as a comparison of K2Ca2Si8O19 to closely related structures.

  13. Scientific Opinion on the re-evaluation of propionic acid (E 280, sodium propionate (E 281, calcium propionate (E 282 and potassium propionate (E 283 as food additives

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Additives and Nutrient Sources added to food (ANS

    2014-07-01

    Full Text Available The EFSA ANS Panel provides a scientific opinion re-evaluating the safety of propionic acid (E 280, sodium propionate (E 281, calcium propionate (E 282 and potassium propionate (E 283 which are authorised as food additives in the EU and have been previously evaluated by the SCF and JECFA. JECFA allocated an ADI “not limited”. The SCF concluded that potassium propionate could be added to the list of preservatives and established an ADI ”not specified”. Propionates are naturally occurring substances in the normal diet. The Panel considered that forestomach hyperplasia reported in long-term studies in rodents is not a relevant endpoint for humans because humans lack this organ. Based on the reported presence of reversible diffuse epithelial hyperplasia in the oesophagus the LOAEL for a 90-day study in dogs was considered by the Panel to be 1 % propionic acid in the diet and the NOAEL to be 0.3 % propionic acid in the diet. The Panel considered that there is no concern with respect to genotoxicity and carcinogenicity. The Panel concluded that the present database did not allow allocation of an ADI for propionic acid - propionates. The overall mean and 95th percentile exposures to propionic acid - propionates resulting from their use as food additives (major contributor to exposure ranged from 0.7-21.1 and 3.6-40.8 mg/kg bw/day, respectively. The Panel noted that the concentration provoking site of contact effect in the 90-day study in dogs (1 % propionic acid in the diet is a factor of three higher than the concentration of propionic acid - propionates in food at the highest permitted level and concluded that for food as consumed, there would not be a safety concern from the maximum concentrations of propionic acid and its salts at their currently authorised uses and use levels as food additives.

  14. 硅钙镁磷钾肥不同用量对超级稻产量及磷钾吸收利用的影响%The Effects of Silicon, Calcium, Magnesium, Phosphorus and Potassium Fertilization Level on Yield and Phosphorus and Potassium Absorption of Super Rice

    Institute of Scientific and Technical Information of China (English)

    李敏; 叶舒娅; 刘枫; 郭熙盛; 黄义德

    2014-01-01

    In order to explore the application effect of silicon, calcium, magnesium, phosphorus and potassium fertilizer on super rice, a field plots experiment was conducted to investigate the effects of silicon, calcium, magnesium, phosphorus and potassium fertilizer on the yield and phosphorus and potassium absorption of rice and soil nutrient contents. The results showed that in comparison with farmer custom fertilizer (CF 1) and custom fertilizer with phosphorus and potassium halving (CF2), silicon, calcium, magnesium, phosphorus and potassium fertilizer could increase yield of super-rice, and the yield increased 1.87%-10.65% and 3.69%-12.63%, respectively. The yield was consistent between T100 and T125. Silicon, calcium, magnesium, phosphorus and potassium fertilizer could increase filled grain. With the increasing of the application, contents and uptake amounts of phosphorus and potassium in grain and straw increased. Silicon, calcium, magnesium, phosphorus and potassium fertilizer could increase soil available phosphorus, available potassium and pH value, but had no significant effects on soil total nitrogen, total phosphorus, organic matter and available nitrogen content. The feasible silicon, calcium, magnesium, phosphorus and potassium fertilization was 1500 kg/hm2 (T100) and the yield, phosphorus and potassium absorption and soil nutrient contents would be increased.%为了探讨硅钙镁磷钾肥在超级稻上施用效果,通过采用田间小区试验,研究了硅钙镁磷钾肥不同用量和习惯施肥磷钾减半(CF2)配合施用对水稻产量磷钾吸收利用及土壤养分含量的影响。结果表明,施用硅钙镁磷钾肥较习惯施肥能够有效提高超级稻产量,随着施用量的增加而增大,比习惯施肥(CF1)增产1.87%~10.65%,比习惯施肥磷钾减半(CF2)增产3.69%~12.63%,施用量1500 kg/hm2(T100)和1875 kg/hm2(T125)产量结果一致。施用硅钙镁磷钾肥通过提高每穗实粒数来提高水稻产量。

  15. 分光光度法测定钙渣与钾矿混匀度%Spectrophotometric Determination of Evenness of Calcium Slag and Potassium Mineral Mixture

    Institute of Scientific and Technical Information of China (English)

    周美姣; 朱云勤; 胡德庚; 张頔; 郭淑琴

    2012-01-01

    Calcium slag and potassium mineral are the raw materials for the preparation of silicon-calcium potassic fertilizers, and the evenness of their mixture affects directly of the quality of the final product. A study is made by using neutral water as the extractant, the SO4 ~ content in the extract from the mixture is determined by barium chromate spectrophotometry, and the evenness of the mixture is measured. The results of the study show that the relative standard deviation of the method is 1. 38% , the indexed recovery is 97. 5% ~ 100. 4% , the precision and accuracy are satisfactory, the relative error of the evenness determined is in the rang of ± 2% , the operation is simple and rapid, thus satisfying the requirements in determination 5 and the method is applied in production practice.%钙渣和钾矿是制备硅钙钾肥的原料,两者混合均匀程度(混匀度)直接影响最终产品的质量.研究采用中性水作提取剂,通过铬酸钡分光光度法测定钙渣和钾矿混合料的提取液中SO42-的含量,以此来衡量混匀度.研究结果表明:采用该法的测定结果的相对标准偏差为1.38%,加标回收率为97.5%~100.4%,精密度和准确度良好,测定混匀度的相对误差在±2%范围内,操作简单、快速,可满足测定要求并应用于生产实践.

  16. Thermodynamics and Kinetics of Boron Removal from Metallurgical Grade Silicon by Addition of High Basic Potassium Carbonate to Calcium Silicate Slag

    Science.gov (United States)

    Wu, Jijun; Wang, Fanmao; Ma, Wenhui; Lei, Yun; Yang, Bin

    2016-06-01

    In this study, we investigated the thermodynamics and kinetics of boron removal from metallurgical grade silicon (MG-Si) using a calcium silicate slag containing a high basic potassium carbonate. The distribution of boron between slag and silicon was theoretically derived and the distribution coefficients ( L B) of boron with different compositions of CaO, SiO2, and K2CO3 in slag reagents were determined. The maximal value of L B reached 2.08 with a high basicity slag of 40 pctCaO-40 pctSiO2-20 pctK2CO3 (Λ = 0.73). The boron removal rates from MG-Si using CaO-SiO2 and CaO-SiO2-K2CO3 slags at 1823 K (1550 °C) were investigated in an electromagnetic induction furnace. The results showed that the boron concentration in MG-Si can be reduced from 22 to 1.8 ppmw at 1823 K (1550 °C) with 20 pct K2CO3 addition to calcium silicate slag, where the removal efficiency of boron reached 91.8 pct. The mass transfer coefficient ( β S) of boron in binary 50 pctCaO-50 pctSiO2 slag was 3.16 × 10-6 m s-1 at 1823 K (1550 °C) and was 2.43 × 10-5 m s-1 in ternary 40 pctCaO-40 pctSiO2-20 pctK2CO3 slag.

  17. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to calcium and potassium and maintenance of normal acid-base balance (ID 400, 407) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation (EC) No 1924/2006. This opinion addresses the scientific substantiation of health...... claims in relation to calcium and potassium and maintenance of normal acid-base balance. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from...... stakeholders. The food constituents that are the subject of the health claims are calcium and potassium. The Panel considers that calcium and potassium are sufficiently characterised. The claimed effects are “calcium contributes to acid/base balance within metabolism” and “mineral/potassium: key function...

  18. Dopamine midbrain neurons in health and Parkinson's disease: emerging roles of voltage-gated calcium channels and ATP-sensitive potassium channels.

    Science.gov (United States)

    Dragicevic, E; Schiemann, J; Liss, B

    2015-01-22

    Dopamine (DA) releasing midbrain neurons are essential for multiple brain functions, such as voluntary movement, working memory, emotion and cognition. DA midbrain neurons within the substantia nigra (SN) and the ventral tegmental area (VTA) exhibit a variety of distinct axonal projections and cellular properties, and are differentially affected in diseases like schizophrenia, attention deficit hyperactivity disorder, and Parkinson's disease (PD). Apart from having diverse functions in health and disease states, DA midbrain neurons display distinct electrical activity patterns, crucial for DA release. These activity patterns are generated and modulated by specific sets of ion channels. Recently, two ion channels have been identified, not only contributing to these activity patterns and to functional properties of DA midbrain neurons, but also seem to render SN DA neurons particularly vulnerable to degeneration in PD and its animal models: L-type calcium channels (LTCCs) and ATP-sensitive potassium channels (K-ATPs). In this review, we focus on the emerging physiological and pathophysiological roles of these two ion channels (and their complex interplay with other ion channels), particularly in highly vulnerable SN DA neurons, as selective degeneration of these neurons causes the major motor symptoms of PD.

  19. Method development for the determination of calcium, copper, magnesium, manganese, iron, potassium, phosphorus and zinc in different types of breads by microwave induced plasma-atomic emission spectrometry.

    Science.gov (United States)

    Ozbek, Nil; Akman, Suleyman

    2016-06-01

    A novel method was developed for the determination of calcium, magnesium, potassium, iron, copper, zinc, and manganese and phosphorous in various kinds of breads samples sold in Turkey by microwave plasma-atomic emission spectrometry (MIP-AES). Breads were dried at 100 °C for one day, ground thoroughly and then digested using nitric acid/hydrogen per oxide (3:1). The analytes in certified reference wheat flour and maize flour samples were determined in the uncertainty limits of the certified values as well as the analytes added to the mixture of ground bread and acid mixture prior to digestion were recovered quantitatively (>90%). Therefore, all determinations were made by linear calibration technique using aqueous standards. The LOD values for Ca, Cu, Fe, K, Mg, Mn, P and Zn were 13.1, 0.28, 4.47, 118, 1.10, 0.41, 7550 and 3.00 ng mL(-1), respectively. No spectral interference was detected at the working wavelengths of the analytes.

  20. Overexpression of Large-Conductance Calcium-Activated Potassium Channels in Human Glioblastoma Stem-Like Cells and Their Role in Cell Migration.

    Science.gov (United States)

    Rosa, Paolo; Sforna, Luigi; Carlomagno, Silvia; Mangino, Giorgio; Miscusi, Massimo; Pessia, Mauro; Franciolini, Fabio; Calogero, Antonella; Catacuzzeno, Luigi

    2017-09-01

    Glioblastomas (GBMs) are brain tumors characterized by diffuse invasion of cancer cells into the healthy brain parenchyma, and establishment of secondary foci. GBM cells abundantly express large-conductance, calcium-activated potassium (BK) channels that are thought to promote cell invasion. Recent evidence suggests that the GBM high invasive potential mainly originates from a pool of stem-like cells, but the expression and function of BK channels in this cell subpopulation have not been studied. We investigated the expression of BK channels in GBM stem-like cells using electrophysiological and immunochemical techniques, and assessed their involvement in the migratory process of this important cell subpopulation. In U87-MG cells, BK channel expression and function were markedly upregulated by growth conditions that enriched the culture in GBM stem-like cells (U87-NS). Cytofluorimetric analysis further confirmed the appearance of a cell subpopulation that co-expressed high levels of BK channels and CD133, as well as other stem cell markers. A similar association was also found in cells derived from freshly resected GBM biopsies. Finally, transwell migration tests showed that U87-NS cells migration was much more sensitive to BK channel block than U87-MG cells. Our data show that BK channels are highly expressed in GBM stem-like cells, and participate to their high migratory activity. J. Cell. Physiol. 232: 2478-2488, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. Niflumic acid hyperpolarizes smooth muscle cells via calcium-activated potassium channel in spiral modiolar artery of guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Li LI; Ke-tao MA; Lei ZHAO; Jun-qiang SI; Zhong-shuang ZHANG; He ZHU; Jing LI

    2008-01-01

    Aim: The influence of niflumic acid (NFA), a C1- channel antagonist, on the mem-brane potentials in smooth muscle cells (SMC) of the cochlear spiral modiolar artery (SMA) in guinea pigs was examined. Methods: The intracellular recording and whole-cell recording technique were used to record the NFA-induced re-sponse on the acutely-isolated SMA preparation. Results: The SMC had 2 stable but mutually convertible levels of resting potentials (RP), that is, one was near-45 mV and the other was approximately -75 mV, termed as low and high RP, respectively. The bath application of NFA could cause a hyperpolarization in all the low RP cells, but had little effect on high RP cells. The induced responses were concentration-dependent. Large concentrations of NFA (≥100 μmol/L) often in-duced a shift of a low RP to high RP in cells with an initial RP at low level, and NFA (up to 100 μmol/L) had little effect on the membrane potentials of the high RP cells. However, when the high RP cells were depolarized to a level beyond -45 mV by barium and ouabain, NFA hyperpolarized these cells with the similar effect on those cells initially being the low RP. The NFA-induced response was almost completely blocked by charybdotoxin, iberiotoxin, tetraethylammonium, 1,2-bis(2-aminophenoxy) ethane-N,N,N,N,N,-tetraacetic acid tetrakis acetoxymethyl ester, but not by 4-aminopyridine, barium, glipizide, apamin, ouabain, and CdC12. Conclusion: NFA induces a concentration-dependent reversible hyperpolarization in SMC in the cochlear SMA via activation of the Ca2+-activated potassium channels.

  2. Potassium toxicity at low serum potassium levels with refeeding syndrome.

    Science.gov (United States)

    Vemula, Praveen; Abela, Oliver G; Narisetty, Keerthy; Rhine, David; Abela, George S

    2015-01-01

    Refeeding syndrome is a life-threatening condition occurring in severely malnourished patients after initiating feeding. Severe hypophosphatemia with reduced adenosine triphosphate production has been implicated, but little data are available regarding electrolyte abnormalities. In this case, we report electrocardiographic changes consistent with hyperkalemia during potassium replacement after a serum level increase from 1.9 to 2.9 mEq/L. This was reversed by lowering serum potassium back to 2.0 mEq/L. In conclusion, the patient with prolonged malnutrition became adapted to low potassium levels and developed potassium toxicity with replacement.

  3. ٍEffect of potassium and calcium application on water use and fruit yield of tomato in a hydroponic system with dynamic and non-uniform distribution of salts

    Directory of Open Access Journals (Sweden)

    A.A. Moezzi

    2012-03-01

    Full Text Available One of the problems for unequal distribution of salts in the root media is toxicity of sodium (Na and reduced uptake of some nutrients, particularly calcium (Ca and potassium (K, by the roots growing in the saline section. There is a hypothesis that addition of Ca and K to these systems might alleviate salt-induced damages to plants. This study was carried out to evaluate the effect of Ca and K application on fruit yield, water use and crop per drop (CPD of tomato (Lycopersicon esculentum var. Falcato F1 plants grown in a hydroponic system with unequal distribution of salts in the root media. Tomato roots were divided into two equal splits and one half was immersed in the full Johnson nutrient solution. In the other root half, 40 mM NaCl solution, alone or in combination with KCl (6 mM, CaCl2 (4 mM, K+Ca (3+2 mM or half-strength Johnson nutrient solution, was applied. A control treatment was also used in which both root splits were immersed in the Johnson nutrient solution (C. The root splits were exchanged every 7 days. Results showed that addition of 40 mM NaCl in one side of the root media resulted in reduction of fresh and dry weight of root and shoot, stem diameter, shoot height, number of leaves and fruit yield of tomato in comparison with the control treatment. Addition of Ca, K+Ca and half-strength Johnson nutrient solution to the saline part of the root media increased significantly the root and shoot growth and fruit yield of tomato compared with the sole application of saline solution. In contrast, addition of K could not alleviate the adverse effects of salinity and even reduced the fruit yield. Application of 40 mM NaCl in one side of the root media reduced significantly the plant water use. Addition of Ca, K+Ca and half-strength Johnson nutrient solution to the saline part of the root media resulted in significant increase in CPD. Addition of Ca, K+Ca and half-strength Johnson nutrient solution caused replacement of 48, 43 and 43

  4. Evaluation of calcium, magnesium, potassium and sodium in biological samples of male human immunodeficiency virus patients with tuberculosis and diarrhea compared to healthy control subjects in Pakistan.

    Science.gov (United States)

    Afridi, Hassan Imran; Kazi, Tasneem Gul; Talpur, Farah Naz; Kazi, Naveed; Naeemullah, Faheem Shah; Arain, Sadaf Sadia; Brahman, Kapil Dev

    2013-01-01

    Electrolyte deficiency has been associated with an increased risk of human immunodeficiency virus type 1 (HIV-1) disease progression and mortality. This study examined the association between low electrolyte concentrations in blood and scalp hair and the presence of opportunistic infections in patients with acquired immune deficiency syndrome (AIDS). Sixty-two male HIV positive patients (HIV-1) from various cities in Pakistan were recruited to the study. These Patients were divided into two groups according to secondary infections (tuberculosis and high fever with diarrhea), and biological samples (scalp hair, serum, blood and urine) were collected from them. As a comparative control group, 120 healthy subjects (males) of the same age group (31 - 45 years), socio-economic status, localities and dietary habits were also included in the study. The elements in the biological samples were analyzed by flame atomic absorption spectrophotometry after microwave-assisted acid digestion. Validity and accuracy of the methodology were checked using certified reference materials (CRMs) and against values obtained by a conventional wet acid digestion method on the same CRMs. The results indicated significantly lower levels of calcium, potassium, magnesium and natrium in all analyzed biological samples (blood, serum and scalp hair) of male patients with Acquired Immune Deficiency Syndrome (AIDS) in comparison to healthy controls (p < 0.01), while the levels of these elements were found to be higher in urine samples of the AIDS patients than in those of the control group. These data offer guidance to clinicians and other professionals investigating the deficiency of electrolytes in biological samples (scalp hair, serum and blood) of AIDS patients in relation to healthy subjects.

  5. Effect of nitric oxide-induced tyrosine phosphorylation of calcium-activated potassium channel α subunit on vascular hyporesponsiveness in rats

    Institute of Scientific and Technical Information of China (English)

    ZHOU Rong; LIU Liang-ming; HU De-yao

    2005-01-01

    Objective: To study the effect of nitric oxide-induced tyrosine phosphorylation of large-conductance calcium-activated potassium (BKCa) channel α subunit on vascular hyporesponsiveness in rats. Methods: A total of 46 Wistar rats of either sex, weighing 250 g±20 g, were used in this study. Models of vascular hyporesponsiveness induced by hemorrhagic shock (30 mm Hg for 2 hours) in vivo and by L-arginine in vitro were established respectively. The vascular responsiveness of isolated superior mesenteric arteries to norepinephrine was observed. Tyrosine phosphorylation of BKCa α subunit was evaluated with methods of immunoprecipitation and Western blotting. Results: In the smooth muscle cells of the superior mesenteric arteries, the expression of BKCa α subunit tyrosine phosphorylation increased following hemorrhagic shock, and L-arginine could induce BKCa channel α subunit tyrosine phosphorylation in a time- and dose-dependent manner. L-NAME (Nω-nitro-L-arginine-methyl-ester), a nitric oxide synthetase inhibitor, could partly restore the decreased vasoresponsiveness of the superior mesenteric arteries after hemorrhagic shock in rats. Down-regulating the protein tyrosine phosphorylation with genistein, a widely-used special protein tyrosine kinase inhibitor, could partly improve the decreased vasoresponsiveness of the superior mesenteric arteries induced by L-arginine in vitro, while up-regulating the protein tyrosine phosphorylation with Na3VO4, a protein tyrosine phosphatase inhibitor, could further decrease the nitric oxide-induced vascular hyporesponsiveness, which could be partly ameliorated by 0.1 mmol/L tetrabutylammonium chloride (TEA), a selective BKCa inhibitor at this concentration. Conclusions: Nitric oxide can induce the tyrosine phosphorylation of BKCa α subunit, which influences the vascular hyporesponsiveness in hemorrhagic shock rats or induced by L-arginine in vitro.

  6. Intermediate-Conductance-Ca2-Activated K Channel Intermediate-Conductance Calcium-Activated Potassium Channel (IKCa1) is Upregulated and Promotes Cell Proliferation in Cervical Cancer

    Science.gov (United States)

    Liu, Ling; Zhan, Ping; Nie, Dan; Fan, Lingye; Lin, Hairui; Gao, Lanyang; Mao, Xiguang

    2017-01-01

    Background Accumulating data point to intermediate-conductance calcium-activated potassium channel (IKCa1) as a key player in controlling cell cycle progression and proliferation of human cancer cells. However, the role that IKCa1 plays in the growth of human cervical cancer cells is largely unexplored. Material/Methods In this study, Western blot analysis, immunohistochemical staining, and RT-PCR were first used for IKCa1protein and gene expression assays in cervical cancer tissues and HeLa cells. Then, IKCa1 channel blocker and siRNA were employed to inhibit the functionality of IKCa1 and downregulate gene expression in HeLa cells, respectively. After these treatments, we examined the level of cell proliferation by MTT method and measured IKCa1 currents by conventional whole-cell patch clamp technique. Cell apoptosis was assessed using the Annexin V-FITC/Propidium Iodide (PI) double-staining apoptosis detection kit. Results We demonstrated that IKCa1 mRNA and protein are preferentially expressed in cervical cancer tissues and HeLa cells. We also showed that the IKCa1 channel blocker, clotrimazole, and IKCa1 channel siRNA can be used to suppress cervical cancer cell proliferation and decrease IKCa1 channel current. IKCa1 downregulation by specific siRNAs induced a significant increase in the proportion of apoptotic cells in HeLa cells. Conclusions IKCa1 is overexpressed in cervical cancer tissues, and IKCa1 upregulation in cervical cancer cell linea enhances cell proliferation, partly by reducing the proportion of apoptotic cells. PMID:28280257

  7. Two distinct pools of large-conductance calcium-activated potassium channels in the somatic plasma membrane of central principal neurons

    Science.gov (United States)

    Kaufmann, W.A.; Kasugai, Y.; Ferraguti, F.; Storm, J.F.

    2010-01-01

    Although nerve cell membranes are often assumed to be uniform with respect to electrical properties, there is increasing evidence for compartmentalization into subdomains with heterogeneous impacts on the overall cell function. Such microdomains are characterized by specific sets of proteins determining their functional properties. Recently, clustering of large-conductance calcium-activated potassium (BKCa) channels was shown at sites of subsurface membrane cisterns in cerebellar Purkinje cells (PC), where they likely participate in building a subcellular signaling unit, the 'PLasmERosome'. By applying SDS-digested freeze-fracture replica labeling (SDS-FRL) and postembedding immunogold electron microscopy, we have now studied the spatial organization of somatic BKCa channels in neocortical layer 5 pyramidal neurons, principal neurons of the central and basolateral amygdaloid nuclei, hippocampal pyramidal neurons and dentate gyrus (DG) granule cells to establish whether there is a common organizational principle in the distribution of BKCa channels in central principal neurons. In all cell types analyzed, somatic BKCa channels were found to be non-homogenously distributed in the plasma membrane, forming two pools of channels with one pool consisting of clustered channels and the other of scattered channels in the extrasynaptic membrane. Quantitative analysis by means of SDS-FRL revealed that about two-thirds of BKCa channels belong to the scattered pool and about one-third to the clustered pool in principal cell somata. Overall densities of channels in both pools differed in the different cell types analyzed, although being considerably lower compared to cerebellar PC. Postembedding immunogold labeling revealed association of clustered channels with subsurface membrane cisterns and confirmed extrasynaptic localization of scattered channels. This study indicates a common organizational principle for somatic BKCa channels in central principal neurons with the

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-01-01

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

  9. Calcium D-saccharate

    DEFF Research Database (Denmark)

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

    2016-01-01

    K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d......-saccharate becomes spontaneously supersaturated with both d-gluconate and d-saccharate calcium salts, from which only calcium d-saccharate slowly precipitates. Calcium d-saccharate is suggested to act as a stabilizer of supersaturated solutions of other calcium hydroxycarboxylates with endothermic complex formation...

  10. Stimulation of large-conductance calcium-activated potassium channels inhibits neurogenic contraction of human bladder from patients with urinary symptoms and reverses acetic acid-induced bladder hyperactivity in rats.

    Science.gov (United States)

    La Fuente, José M; Fernández, Argentina; Cuevas, Pedro; González-Corrochano, Rocío; Chen, Mao Xiang; Angulo, Javier

    2014-07-15

    We have analysed the effects of large-conductance calcium-activated potassium channel (BK) stimulation on neurogenic and myogenic contraction of human bladder from healthy subjects and patients with urinary symptoms and evaluated the efficacy of activating BK to relief bladder hyperactivity in rats. Bladder specimens were obtained from organ donors and from men with benign prostatic hyperplasia (BPH). Contractions elicited by electrical field stimulation (EFS) and carbachol (CCh) were evaluated in isolated bladder strips. in vivo cystometric recordings were obtained in anesthetized rats under control and acetic acid-induced hyperactive conditions. Neurogenic contractions of human bladder were potentiated by blockade of BK and small-conductance calcium-activated potassium channels (SK) but were unaffected by the blockade of intermediate calcium-activated potassium channels (IK). EFS-induced contractions were inhibited by BK stimulation with NS-8 or NS1619 or by SK/IK stimulation with NS309 (3µM). CCh-induced contractions were not modified by blockade or stimulation of BK, IK or SK. The anti-cholinergic agent, oxybutynin (0.3µM) inhibited either neurogenic or CCh-induced contractions. Neurogenic contractions of bladders from BPH patients were less sensitive to BK inhibition and more sensitive to BK activation than healthy bladders. The BK activator, NS-8 (5mg/kg; i.v.), reversed bladder hyperactivity induced by acetic acid in rats, while oxybutynin was ineffective. NS-8 did not significantly impact blood pressure or heart rate. BK stimulation specifically inhibits neurogenic contractions in patients with urinary symptoms and relieves bladder hyperactivity in vivo without compromising bladder contractile capacity or cardiovascular safety, supporting its potential therapeutic use for relieving bladder overactivity.

  11. Potassium Iodide

    Science.gov (United States)

    Potassium iodide is used to protect the thyroid gland from taking in radioactive iodine that may be released ... damage the thyroid gland. You should only take potassium iodide if there is a nuclear radiation emergency and ...

  12. 心房肌细胞钙通道和钾通道免疫电镜定位研究%The study of distribution of calcium channel and potassium channel in atrial myocytes by immunoelectromicroscopy

    Institute of Scientific and Technical Information of China (English)

    袁平; 张建成; 何爱华; 颜永碧

    2002-01-01

    @@ 离子通道是一种跨膜蛋白,迄今为止,尚未见关于离子通道的细胞内分布情况的报道.心脏L-型电压依赖钙通道(L-type voltage dependent calcium channel, LVDCC)和电压依赖KV4.3钾通道(voltage dependent potassium channel,VDKV4.3)对心肌细胞动作电位有重要作用.

  13. Localization of large conductance calcium-activated potassium channels and their effect on calcitonin gene-related peptide release in the rat trigemino-neuronal pathway.

    Science.gov (United States)

    Wulf-Johansson, H; Amrutkar, D V; Hay-Schmidt, A; Poulsen, A N; Klaerke, D A; Olesen, J; Jansen-Olesen, I

    2010-06-02

    Large conductance calcium-activated potassium (BK(Ca)) channels are membrane proteins contributing to electrical propagation through neurons. Calcitonin gene-related peptide (CGRP) is a neuropeptide found in the trigeminovascular system (TGVS). Both BK(Ca) channels and CGRP are involved in migraine pathophysiology. Here we study the expression and localization of BK(Ca) channels and CGRP in the rat trigeminal ganglion (TG) and the trigeminal nucleus caudalis (TNC) as these structures are involved in migraine pain. Also the effect of the BK(Ca) channel blocker iberiotoxin and the BK(Ca) channel opener NS11021 on CGRP release from isolated TG and TNC was investigated. By RT-PCR, BK(Ca) channel mRNA was detected in the TG and the TNC. A significant difference in BK(Ca) channel mRNA transcript levels were found using qPCR between the TNC as compared to the TG. The BK(Ca) channel protein was more expressed in the TNC as compared to the TG shown by western blotting. Immunohistochemistry identified BK(Ca) channels in the nerve cell bodies of the TG and the TNC. The beta2- and beta4-subunit proteins were found in the TG and the TNC. They were both more expressed in the TNC as compared to TG shown by western blotting. In isolated TNC, the BK(Ca) channel blocker iberiotoxin induced a concentration-dependent release of CGRP that was attenuated by the BK(Ca) channel opener NS11021. No effect on basal CGRP release was found by NS11021 in isolated TG or TNC or by iberiotoxin in TG. In conclusion, we found both BK(Ca) channel mRNA and protein expression in the TG and the TNC. The BK(Ca) channel protein and the modulatory beta2- and beta4-subunt proteins were more expressed in the TNC than in the TG. Iberiotoxin induced an increase in CGRP release from the TNC that was attenuated by NS11021. Thus, BK(Ca) channels might have a role in trigeminovascular pain transmission.

  14. The influence of various doses of phosphorus and of the addition of calcium or potassium fertilization upon the yield of tomatoes in Wrocław hydroponic culture using two intensities of light

    Directory of Open Access Journals (Sweden)

    Z. Gumicka

    2013-12-01

    Full Text Available Two experiments were carried out with phosphate fertilization of tomatoes in hydroponic culture. It has been proved that an additional dose of phosphorus given during the second cluster bloom, caused an yield increase. The optimal dose is 12 g of superphosphate (16% P2O5 per plant. The "green back" symptoms did not appear in these conditions. The parallel additional applying of calcium or potassium gave a decrease of the yield. When the light intensity was lowered to about 50%, the yield has decreased by half. In these conditions an additional applying of calcium (0,4 g CaCO3 and phosphorus (1g superphosphate annulated the negative influence of the low light intensity.

  15. 土壤施钙对芒果果实钾、钙、镁含量及品质的影响%Effects of different lime nitrate application rates on potassium, calcium and magnesium content and quality in mango

    Institute of Scientific and Technical Information of China (English)

    李华东; 白亭玉; 郑妍; 张贺; 林电

    2014-01-01

    以“台农1号”芒果为试材,田间试验研究了花前土施不同用量硝酸钙对芒果果实钾、钙、镁含量及产量、品质的影响。结果表明:(1)与不施钙相比,土施钙肥可明显提高果实糖酸比,其原因主要是降低了可滴定酸含量,提高了可溶性糖含量,同时可显著提高果实Vc含量,降低贮藏期果实发病率,在土施钙150 g/株时产量最高,增产率为14.25%。(2)在一定钙用量范围内,土施钙肥可显著提高果肉钙含量,使果皮、果肉与果核的钾、镁含量下降。(3)果皮、果肉及果核钙含量与钙肥用量呈正相关,钾、镁含量与钙肥用量呈负相关。(4)果实可溶性糖含量、 Vc含量及糖酸比与钙肥用量呈正相关,果实可溶性固形物含量、可滴定酸含量、失重率、发病率与钙肥用量呈负相关。土壤增施钙肥有利于提高芒果果实品质,提高果实耐贮性。%A field trial was undertaken to evaluate the effects of applying Ca( NO3 ) 2 in soil before flower period on the contents of potassium, calcium, magnesium and quality of “tainung No. 1” mango. The results showed that: (1) Compare with the results of the control, applying calcium fertilizer could obviously increase the fruit sugar acid ratio because of the increase of content of soluble sugars and acidity reduced, and improve the vitamin C in the fruit, reduce the rotten fruit rate during stor-age. The highest yield occurred when 150 g/plant calcium was applicated, and the yield increased by 14. 25% compared to the control. (2) By applying calcium fertilizer, the calcium content of pulp in fruit was significantly increased, the magnesi-um and potassium contents of peel, pulp and seed in fruit reduced. (3) The calcium contents of peel, pulp and seed in fruit had positive correlation with the calcium application amounts, and the potassium and magnesium contents of peel, pulp and seed in fruit had negative correlation with

  16. The role of calcium sensor-interacting protein kinases in plant adaptation to potassium-deficiency: new answers to old questions

    Institute of Scientific and Technical Information of China (English)

    Anna Amtmann; Patrick Armengaud

    2007-01-01

    @@ Potassium (K+) is an essential macronutrient for all living (anisms) and large amounts are required for plant growth (d) development. In many regions of Asia K+-fertilization (as) been neglected and soils have become K+-depleted.

  17. RADIOACTIVITY AND PHYSIOLOGICAL ACTION OF POTASSIUM.

    Science.gov (United States)

    Loeb, R F

    1920-11-20

    1. The non-radioactive cesium ion can replace the potassium ion almost quantitatively in solutions required for the development of the egg of the sea urchin into swimming blastulae. 2. Thorium chloride and uranium acetate cannot replace the potassium chloride in the solutions required for the development of the egg. 3. Thorium chloride and uranium acetate do not antagonize the action of the potassium contained in sea water upon the development of eggs.

  18. Potassium physiology.

    Science.gov (United States)

    Thier, S O

    1986-04-25

    Potassium is the most abundant exchangeable cation in the body. It exists predominantly in the intracellular fluid at concentrations of 140 to 150 meq/liter and in the extracellular fluid at concentrations of 3.5 to 5 meq/liter. The maintenance of the serum potassium concentration is a complex bodily function and results from the balance between intake, excretion, and distribution between intracellular and extracellular space. Ingested potassium is virtually completely absorbed from and minimally excreted through the intestine under nonpathologic circumstances. Renal excretion of potassium, which is the major chronic protective mechanism against abnormalities in potassium balance, depends on filtration, reabsorption, and a highly regulated distal nephron secretory process. Factors regulating potassium secretion include prior potassium intake, intracellular potassium, delivery of sodium chloride and poorly reabsorbable anions to the distal nephron, the urine flow rate, hormones such as aldosterone and beta-catecholamines, and the integrity of the renal tubular cell. The maintenance of distribution between the inside and outside of cells depends on the integrity of the cell membrane and its pumps, osmolality, pH, and the hormones insulin, aldosterone, beta 2-catecholamines, alpha-catecholamines, and prostaglandins. Both distribution across cell membranes and/or renal excretion of potassium may be altered by pharmacologic agents such as diuretics, alpha- and beta-catechol antagonists and agonists, depolarizing agents, and digitalis. Problems with hypokalemia and hyperkalemia can be analyzed on the basis of potassium physiology and pharmacology; proper treatment depends on an accurate analysis.

  19. Application of Anhydrous Calcium Sulfate as a Partial Replacement for Titanium Dioxide%无水硫酸钙部分替代钛白粉的应用

    Institute of Scientific and Technical Information of China (English)

    黄明杰; 邵聂

    2013-01-01

    The present price of titanium dioxide is high, but research of titanium composite pigment in domestic is still in the initial stage. Titanium dioxide has many advantages, but people have to consider other products replacing titanium dioxide due to its expensive price. In order to save the expensive titanium dioxide and reduce costs, people have been actively researched and developed and used efficient and inexpensive extender pigments instead of titanium dioxide for a long time. It is imperative to research new product replacing titanium dioxide partly. Because calcium sulfate has good whiteness and gelling property, it can partly replace titanium dioxide in the coating, maximum substitution is 20%of titanium dioxide.%  目前钛白粉的价格居高不下,而且在国内钛复合颜料的研究尚处于起步阶段。钛白粉具有很多优势,但是其昂贵的价格让人们不得不考虑采用其他的产品来替代钛白粉。为了节省昂贵的钛白粉,降低成本,长期以来人们都积极地研究和开发利用高效价廉的体质颜料取代钛白粉,研究新的产品部分替代钛白粉势在必行。由于硫酸钙具有良好的白度以及胶凝性,故可部分替代钛白粉添加到涂料中,最大替代量为钛白粉用量的20%。

  20. 大电导钙激活钾通道对平滑肌的调控作用研究进展%Progress in regulation of large-conductance calcium-activated potassium channels on smooth muscle

    Institute of Scientific and Technical Information of China (English)

    李汉高; 李芳萍; 张雪梅

    2011-01-01

    Potassium channels are important to distribute in almost each tissue and implicated with many functions of cells, such as the formation of action potential and signal transduction. Large-conductance calcium-activated potassium channel ( BKca/Maxi K) is one of the potassium channels and expressed in many types of cells. The activation of BKca/Maxi K is able to induce the hyperpolarization of plasma membrane and the inhibition of voltagedependent calcium channel activity. So BKca/Maxi K plays an important role in the relaxation of smooth muscle.The pathogenesis of many diseases is also involved in activation and inactivation, expression, or mutation of this potassium channel. BKca/Maxi K participates in the regulation of cardiovascular smooth muscle, myometrial smooth muscle, smooth muscle in the airway and penile erection. Especially, the gene therapy of BKca/Maxi K to erectile dysfunction enjoys some advantages over medication.%钾通道是组织器官中的一种重要通道,几乎所有的组织中都有该通道的分布,并且它在调节细胞功能方面起着极其重要的作用,例如动作电位的形成和信号传导等.大电导钙激活钾通道(BKca/Maxi K)以其广泛的分布,以及参与调节多种细胞功能吸引了更多研究者的关注.BKca/Maxi K的激活可导致细胞膜的超极化,从而抑制电压依赖性钙通道的激活,抑制钙离子内流,引起平滑肌舒张.近年来研究发现,BKca/Maxi K的激活、失活和变异与多种疾病的发病有关,BKca/Maxi K对心血管平滑肌、子宫平滑肌、呼吸道平滑肌和阴茎勃起等具有调控作用,尤其是其基因疗法对阴茎勃起障碍的治疗逐渐显现出较大的优势.

  1. Calcium, potassium and magnesium treatment of Chrysanthemum morifolium cv. "Bi Time" and callogenesis in vitro Tratamento de plantas matrizes de Chrysanthemum morifolium cv. "Bi Time" com Ca2+, K+ E Mg2+ e calogênese in vitro

    Directory of Open Access Journals (Sweden)

    Fábio Borgatto

    2002-12-01

    Full Text Available The chemical composition and vegetative vigor of the donor plant are essential for the satisfactory performance of explants in vitro. In order to test the effect of potassium, calcium and magnesium nutritional status of Chrysanthemum morifolium plants on callogenesis in vitro, pot plants growing in sand were irrigated with nutrient solution containing different levels of potassium (0; 58.5; 117 and 234 mg L-1, calcium (0; 50; 100 e 200 mg L-1 and magnesium (0;12; 48 e 96 mg L-1. After 30 and 45 days, explants (shoot segments and leaf discs were collected, desinfected and inoculated on MS solid medium supplemented with 0.1 mg L-1 of kinetin and 5.0 mg L-1 of nafthalene acetic acid for callogenesis induction. Callogenesis evaluated as callus fresh weight was affected by nutrients treatment. Callus growth on leaf explants was inversely proporcional to potassium concentration and directly proportional to magnesium concentration in shoot explants. The calcium effect on callogensis of leaf explants was dependent on treatment duration. For 30 days treatment callogenseis was inversely related to calcium concentration and after 45 days was directly related to calcium concentration.A composição química e o vigor vegetativo de plantas matrizes são essenciais no desenvolvimento de explantes in vitro. Com o objetivo de testar o efeito do estado nutricional de plantas matrizes de Chrysanthemum morifolium no processo de calogênese in vitro, plantas crescendo em vasos contendo areia lavada foram irrigadas com soluções nutritivas contendo diferentes concentrações de cálcio (0, 50, 100 e 200 mg L-1, potássio (0, 58,5, 117 e 234 mg L-1, e magnésio (0,12, 48 e 96 mg L-1. Aos 30 e 45 dias de duração do tratamento com solução nutritiva, explantes (segmento caulinar e foliar das matrizes foram coletados, desinfestados e inoculados em meio de cultura MS sólido suplementado com 0,1 mg L-1 de Kin e 5,0 mg L-1 NAA. A calogênese foi afetada pelos

  2. Nutrients from dairy foods are difficult to replace in diets of Americans: food pattern modeling and an analyses of the National Health and Nutrition Examination Survey 2003-2006.

    Science.gov (United States)

    Fulgoni, Victor L; Keast, Debra R; Auestad, Nancy; Quann, Erin E

    2011-10-01

    Because dairy products provide shortfall nutrients (eg, calcium, potassium, and vitamin D) and other important nutrients, this study hypothesized that it would be difficult for Americans to meet nutritional requirements for these nutrients in the absence of dairy product consumption or when recommended nondairy calcium sources are consumed. To test this hypothesis, MyPyramid dietary pattern modeling exercises and an analyses of data from the National Health and Nutrition Examination Survey 2003-2006 were conducted in those aged at least 2 years (n = 16 822). Impact of adding or removing 1 serving of dairy, removing all dairy, and replacing dairy with nondairy calcium sources was evaluated. Dietary pattern modeling indicated that at least 3 servings of dairy foods are needed to help individuals meet recommendations for nutrients, such as calcium and magnesium, and 4 servings may be needed to help some groups meet potassium recommendations. A calcium-equivalent serving of dairy requires 1.1 servings of fortified soy beverage, 0.6 serving of fortified orange juice, 1.2 servings of bony fish, or 2.2 servings of leafy greens. The replacement of dairy with calcium-equivalent foods alters the overall nutritional profile of the diet and affects nutrients including protein, potassium, magnesium, phosphorus, riboflavin, vitamins A, D and B(12). Similar modeling exercises using consumption data from the National Health and Nutrition Examination Survey also demonstrated that nondairy calcium replacement foods are not a nutritionally equivalent substitute for dairy products. In conclusion, although it is possible to meet calcium intake recommendations without consuming dairy foods, calcium replacement foods are not a nutritionally equivalent substitute for dairy foods and consumption of a calcium-equivalent amount of some nondairy foods is unrealistic.

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

    NARCIS (Netherlands)

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

    2009-01-01

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

  4. Influência do veículo na eficácia da reposição de potássio em ratos hipocalêmicos Vehicle influence on potassium replacement effectiveness in hypokalemic rats

    Directory of Open Access Journals (Sweden)

    Márcio Petenusso

    2009-09-01

    INTRODUCTION: Patients who undergo cardiac surgery are commonly treated with diuretic therapy for the management of volume overload. The concern of hypokalemia important in the adult population submitted to cardiac surgery has been described. Intravenous potassium (K+ replacement dilution is only recommended with sodium chloride 0.9% solution (SF0.9%, likely due to the putative effects of glucose solution 5% (SG5% on insulin secretion, which influence K+ replacement quality. However, it is not yet experimentally proved the influence of SF0.9% and SG5% on K+ replacement quality. Objectives: To evaluate the effects of different vehicles of K+ replacement on blood K+ levels in furosemide hypokalemic rats. METHODS: Male Wistar rats divided into four groups: K+SF, K+SG, SF and SG. Jugular vein cannulation for K+ replacement and femoral vein cannulation for blood analysis. Furosemide (50mg/kg to induce hypokalemia. We prepared the following solutions: vehicle 1.6mL (SF0.9% or SG5% + 0.4 mL de K+ (19.1% and for control groups only vehicle 2 mL. Furosemide (50 mg/kg was used to induce hypokalaemia, it was analyzed potassium plasmatic levels 24 hours before furosemide injection, 24 hours after furosemide injection and 30 minutes after post-replacement. RESULTS: There was no significative difference in blood K+ levels before furosemide administration, after hypokalemic induction and after K+ replacement among all groups. Only SF+K presented blood Na+ levels increaseafter K+ replacement (P<0.05. CONCLUSION: K+ replacement in different vehicles did not affect blood K+ levels in rats

  5. Modulating effect of calcium activated potassium and chloride channels on detrusor instability%钙激活钾/氯通道对大鼠逼尿肌不稳定调节作用的实验研究

    Institute of Scientific and Technical Information of China (English)

    杨航; 宋波; 金锡御; 杨昕

    2003-01-01

    目的研究钙激活钾/氯通道对逼尿肌不稳定的调节作用的变化,探讨其在逼尿肌不稳定(Detrusor instability,DI)发生中的作用.方法采用Wistar大鼠DI模型,常规制备正常及DI逼尿肌条,体外张力测定其自发收缩频率和幅度,观察通道阻断剂及开放剂的作用.结果 DI组自发收缩频率与张力较对照组显著增加.大电导钙激活钾通道(Big conductance calcium activated potassium channel,BKca)阻断后,对照组频率降低而张力增加,DI组仅频率明显提高,开放后对照组频率与张力均降低,DI组仅频率明显下降.小电导钙激活钾通道(Small conductance calcium activated potassium channel,SKca)阻断后两组的频率与张力均明显增加,而开放后则对照组均降低,DI组仅频率下降.钾通道阻断或开放后对照组频率与张力的变化幅度明显高于DI组.钙激活氯通道(Calcium activated chloride channel,Clca)阻断后,DI组频率与张力下降,而对照组无明显改变.结论钙激活钾/氯通道反馈调节逼尿肌的收缩,DI时Kca作用下调而Clca作用上调,提示钙相关的调节异常在DI的发生中具有重要作用.

  6. The critical role of lipid rafts nanodomains in the cross-talk between calcium and reactive oxygen and nitrogen species in cerebellar granule neurons apoptosis by extracellular potassium deprivation

    Directory of Open Access Journals (Sweden)

    Carlos Gutierrez-Merino

    2016-01-01

    Full Text Available The apoptosis of cerebellar granule neurons (CGN induced by low-potassium in serum free medium in vitro has become a widely used model for neuronal apoptosis during in vivo brain development. In this review we shall summarize first the basic features of this model for neuronal apoptosis. Next, we shall focus on the L-type calcium channels (LTCC inactivation as the primary pro-apoptotic signal in low K+-induced CGN death. This apoptotic process can be split into two major and sequential cellular signaling phases: one reversible phase that offers a temporal window for therapeutic interventions to prevent neuronal death, and an irreversible later phase. Therefore, we shall comment next the critical role of reactive oxygen species (ROS production and major ROS sources triggering the entry of CGN in the irreversible stages of low K+-induced apoptosis. Then, we shall present the experimental evidences showing clustering of LTCC and ROS producing enzymes in plasma membrane lipid rafts of CGN matured in vitro, which have opened new perspectives for cell signaling in the early and reversible phase of this apoptosis. The role of lipid rafts nanodomains as fast response calcium/nitric oxide transducers of the switch of CGN to low K+ medium will be discussed next. The two major conclusions drawn from this review are: (1 deregulation of the pool of cytochrome b5 reductase associated to plasma membrane-lipid rafts, at least in part due to overexpression of cytochrome b5, can account for the critical superoxide anion overshot which triggers the entry in the irreversible phase of low K+ apoptosis of CGN, and (2 LTCC inactivation is rapidly transduced by lipid rafts nanodomains into a large drop of cytosolic calcium, a switch-off of nitric oxide production and subsequent inactivation of survival signaling pathways dependent on the activity of CaMKII, PKA and Akt/PKB kinases.

  7. Identification of mutations in SLC24A4, encoding a potassium-dependent sodium/calcium exchanger, as a cause of amelogenesis imperfecta.

    Science.gov (United States)

    Parry, David A; Poulter, James A; Logan, Clare V; Brookes, Steven J; Jafri, Hussain; Ferguson, Christopher H; Anwari, Babra M; Rashid, Yasmin; Zhao, Haiqing; Johnson, Colin A; Inglehearn, Chris F; Mighell, Alan J

    2013-02-07

    A combination of autozygosity mapping and exome sequencing identified a null mutation in SLC24A4 in a family with hypomineralized amelogenesis imperfect a (AI), a condition in which tooth enamel formation fails. SLC24A4 encodes a calcium transporter upregulated in ameloblasts during the maturation stage of amelogenesis. Screening of further AI families identified a missense mutation in the ion-binding site of SLC24A4 expected to severely diminish or abolish the ion transport function of the protein. Furthermore, examination of previously generated Slc24a4 null mice identified a severe defect in tooth enamel that reflects impaired amelogenesis. These findings support a key role for SLC24A4 in calcium transport during enamel formation.

  8. Alleviating negative effects of irrigation-water salinity on growth and vase life of gerbera by foliar spray of calcium chloride and potassium silicate

    OpenAIRE

    A. Mohammadi Torkashvand

    2015-01-01

    The required water for greenhouses in Kishestan, Soume-e-Sara town, Guilan province, Iran, is mainly provided by underground resources that have inappropriate quality. One way to reduce the impact of salinity an plant growth is proper nutrition. This greenhouse research was conducted to evaluate the effect of water salinity and foliar spray of calcium (Ca) and silicon (Si) on growth and vase life of gerbera in a factorial experiment based on compeletly randomized design with two factors. The ...

  9. 单纯低钾饮食和低钾饮食联合小剂量聚苯乙烯磺酸钙治疗维持性血液透析患者高钾血症的疗效比较%Comparison of Effects of Simple Low-potassium Diet and Low-potassium Diet Combine d with Small Doses of Calcium Polystyrene Sulfonate on Treating Hyperkalemia of Maintenance Hemodialysis Patients

    Institute of Scientific and Technical Information of China (English)

    周凌辉; 裴娟; 侯香华; 张恒远; 张燕林

    2016-01-01

    Background Hyperkalemia is a common complication of maintenance hemodialysis patients,and its excessive volatility of serum potassium during hemodialysis interphase is likely to increase the risk of adverse cardiovascular events,therefore,how to maintain stable serum potassium level during hemodialysis interphase is very important. Objective To compare the clinical effects of simple low - potassium diet and low - potassium diet combined with small doses of calcium polystyrene sulfonate on treating hyperkalemia of maintenance hemodialysis patients. Methods According to inclusion criteria, 52 patients who underwent maintenance hemodialysis in Hemodialysis Room of the First Affiliated Hospital of Xiamen University from December 2015 to January 2016 were retrospectively selected with serum potassium level ≥ 5. 0 mmol/ L before hemodialysis. Patients were assigned into control group with 21 cases and research group with 31 cases based on their medication status. Patients in control group received simple low - potassium diet,based on which patients in research group were treated with oral medication of small doses of calcium polystyrene sulfonate. With continuous treatment,patients in two groups were given relevant checks one month after treatment. Serum potassium levels before and after hemodialysis and their difference value,serum calcium before hemodialysis and albumin(Alb)levels of petients in two groups were recorded before and after treatment. Results Serum potassium levels of all patients before and after hemodialysis and their difference value after treatment were lower than those before treatment(P 0. 05). Before treatment,serum potassium level before and after hemodialysis and their difference value,serum calcium before hemodialysis and Alb levels among patients in two groups were not significantly different (P > 0. 05);after treatment,serum potassium level before hemodialysis and difference value of serum potassium levels before and after hemodialysis of

  10. Vascular potassium channels in NVC.

    Science.gov (United States)

    Yamada, K

    2016-01-01

    It has long been proposed that the external potassium ion ([K(+)]0) works as a potent vasodilator in the dynamic regulation of local cerebral blood flow. Astrocytes may play a central role for producing K(+) outflow possibly through calcium-activated potassium channels on the end feet, responding to a rise in the intracellular Ca(2+) concentration, which might well reflect local neuronal activity. A mild elevation of [K(+)]0 in the end feet/vascular smooth muscle space could activate Na(+)/K(+)-ATPase concomitant with inwardly rectifying potassium (Kir) channels in vascular smooth muscle cells, leading to a hyperpolarization of vascular smooth muscle and relaxation of smooth muscle actin-positive vessels. Also proposed notion is endothelial calcium-activated potassium channels and/or inwardly rectifying potassium channel-mediated hyperpolarization of vascular smooth muscle. A larger elevation of [K(+)]0, which may occur pathophysiologically in such as spreading depression or stroke, can trigger a depolarization of vascular smooth muscle cells and vasoconstriction instead.

  11. Potassium Iodide (KI)

    Science.gov (United States)

    ... Health Matters Information on Specific Types of Emergencies Potassium Iodide (KI) Language: English Español (Spanish) Recommend on Facebook ... can I get KI (potassium iodide)? What is Potassium Iodide (KI)? KI (potassium iodide) is a salt of ...

  12. Effects of motilin on potassium and calcium currents of rat's proximal colon smooth muscle cells%胃动素对大鼠近端结肠平滑肌细胞钙钾电流的影响

    Institute of Scientific and Technical Information of China (English)

    吴增祐; 罗和生; 梁成柏; 刘颖; 夏虹

    2012-01-01

    Objective To investigate the effects of motilin on the voltage dependent potassium channel and L-type calcium channel currents in rat proximal colon smooth muscle cells (PCSM) and to explore its mechanism in increasing colonic motility.Methods PCSM were isolated by collagenase.The voltage dependent potassium channel transit outward current (IKA ) and delayed rectifier current (IKdr) and L-type calcium currents (ICa(L)) were measured by whole cell patch clamp technique.Groups were analyzed by paired t-test.Results There was no significant effect of motilin on IKA and IKdr.L-type calcium channel was dose-dependently activated by motilin from 0.5 × 105 mmol/L to 10.0 ×10-5 mmol/L.At 6 × 10-5 mmol/L motilin and under - 10,0 and 10 mV stimulating voltage,maximum current density increased by 154.61%,62.69% and 21.02% respectively and activation kinetics curve obviously left shifted.Half activation voltage decreased from (2.740±1.211) mV prior administration to ( - 25.290 ± 0.614) mV (t =8.534,P =0.007 ) and there was no significant difference in slope factor. Conclusions Motilin increases colonic smooth muscle contraction by promoting calcium influx. However the frequency of colonic smooth muscle contraction could not change with frequency of equilibrium potential and action potential of colonic smooth muscle.%目的 研究胃动素对大鼠近端结肠平滑肌细胞(PCSM)膜电压依赖性钾通道及L型钙通道电流的影响,以探讨其增强结肠运动的机制.方法 采用酶解法分离大鼠PCSM,采用全细胞模式膜片钳技术测定PCSM电压依赖性钾离子通道快速激活型钾电流及延迟整流型钾电流和L型钙电流,组间比较采用配对t检验.结果 胃动素对快速激活型钾电流及延迟整流型钾电流无明显作用.(0.5~10.0)×10-5 mmol/L胃动素浓度依赖性地激活L型钙电流,6×10-5 mmol/L胃动素在-10、0及10 mV刺激电压下,使最大电流密度分别增加154.61%、62.69%及21.02%,激

  13. Determination of the physiological plasmatic values of sodium, potassium and ion calcium and its pre and post exercise Variations in “paso fino” horses in the bogota savannah

    Directory of Open Access Journals (Sweden)

    Camila Valdés Restrepo

    2010-12-01

    Full Text Available This research intends to be a contribution to the Colombian sports equine medicine by providing data on electrolytes standards, a field where there is a substantial lack of literature. This research analyze and determines the normal values of sodium (Na+,potassium (K+ and ion calcium (iCa2+ electrolytes for Colombian Paso Fine horses. The establishment of the reference intervals was done at rest and after exercise. To achieve this, blood samples were taken from farms located in the Bogotá savannah. The 115 mares and stallions used for this study were actively competing with ages ranging from 43 to 78 months old. The samples were taken at three intervals: T0 (Rest,T1 (immediately after 45 minutes of exercise, and T2(1 hour post exercise. The samples were processed using a portable blood analyzer i-STAT® and the data was interpreted using descriptive and comparative statistic according to Turkey tests. The normal values for the breed were established and an electrolytic behavior curve was created, using values inside interval sat 95% confidence levels. The values obtained inmEq/L were: for T0: Na+ (136,71+/-0,23, K+ (4,05+/-0,03, Ca2+ (1,58+/-0,006; for T1: Na+ (136,44+/-0,24, K+ (3,92+/-0,24, Ca2+ (1,42+/-0,008; and for T2: Na+ (137,32+/-0,23, K+ (3,68+/-0,03, Ca2+(1,51+/-0,009. Na+ values increased after exercise. On the contrary K+ and Ca2+ values didn’t increase inT1. Calcium increased on T2 and K+ decreased. The findings of this research will serve as a framework for future analysis. Moreover, further studies and developments in this field are recommended and will prove to be very useful for equine practitioners.

  14. Potassium clavulanate

    Directory of Open Access Journals (Sweden)

    Kotaro Fujii

    2010-08-01

    Full Text Available The title salt, K+·C8H8NO5− [systematic name: potassium (2R,5R,Z-3-(2-hydroxyethylidene-7-oxo-4-oxa-1-azabicyclo[3.2.0]heptane-2-carboxylate], a widely used β-lactam antibiotic, is usually chemically unstable even in the solid state owing to its tendency to be hydrolysed. In the crystal structure, the potassium cations are arranged along the a axis, forming interactions to the carboxylate and hydroxy groups, resulting in one-dimensional ionic columns. These columns are arranged along the b axis, connected by O—H...O hydrogen bonds, forming a layer in the ab plane.

  15. Effects of tocainide and lidocaine on the transmembrane action potentials as related to external potassium and calcium concentrations in guinea-pig papillary muscles.

    Science.gov (United States)

    Oshita, S; Sada, H; Kojima, M; Ban, T

    1980-10-01

    Effects of lidocaine and tocainide on transmembrane potentials were studied in isolated guinea-pig papillary muscles, superfused with modified Tyrode's solution containing either 5.4, 2.7, 10.0 or 8.1 mmol/l potassium concentration, [K]0. The last solution applied contained either 1.8 (normal [Ca]0) or 7.2 mmol/l [Ca]0 (high [Ca]0. The concentrations of lidocaine and tocainide used were 18.5, 36.9 and 73.9 mumol/l and 43.7, 87.5 and 174.9 mumol/l in 5.4 mmol/l [K]0 solution and 36.9 and 87.5 mumol/l in the other solutions, respectively. At the driving rate of 1 Hz in 5.4 mmol/l "K]0 solution, both drugs produced dose-dependently a reduction of maximum rate of rise of action potential (Vmax), together with a prolongation of the relative refractory period. Vmax decreased progressively as the driving rate was increased from 1 Hz (for lidocaine) and from 0.25 Hz (for tocainide) to 5 Hz. This action was accentuated dose-dependently. A slow component (time constant tau = 232 ms for lidocaine, 281--303 ms for tocainide) and slower component (tau = 2.1--3.8 s for tocainide) of the recovery (reactivation) of Vmax were observed in premature responses at 0.25 Hz and in the first response after interruption of the basic driving rate at 1 Hz. All these effects were accentuated with rising [K]0 and attenuated in the high [Ca]0 solution. Both drugs abbreviated the action potential duration at 50% (APD50) and 90% (APD90) levels at 5.4, 8.1 and 10.0 mmol/l [K]0 but not at 2.7 mmol/l [K]0 nor a high [Ca]0 at 1 Hz. These [K]0-dependent effects of lidocaine on Vmax were successfully simulated by the model proposed by Hondeghem and Katzung (1977), with a slight change in parameter values. The mode of interaction of lidocaine with sodium channels in the open, closed and rested states was deduced from these results.

  16. Alleviating negative effects of irrigation-water salinity on growth and vase life of gerbera by foliar spray of calcium chloride and potassium silicate

    Directory of Open Access Journals (Sweden)

    A. Mohammadi Torkashvand

    2015-11-01

    Full Text Available The required water for greenhouses in Kishestan, Soume-e-Sara town, Guilan province, Iran, is mainly provided by underground resources that have inappropriate quality. One way to reduce the impact of salinity an plant growth is proper nutrition. This greenhouse research was conducted to evaluate the effect of water salinity and foliar spray of calcium (Ca and silicon (Si on growth and vase life of gerbera in a factorial experiment based on compeletly randomized design with two factors. The first factor was salinity of irrigation water at two levels (0 and 1.5 dS/m and the second factor was foliar spray at seven levels (without spray, twice Ca spray, four times Ca spray, two times Ca spray + once Si spray, twice Ca spray + twice Si spray, four times Ca spray + once Si spray, and four times Ca spray + twice Si spray, each with three replications. Results showed that four times Ca foliar spray led to an increase in stem hight, stem and neck diameter, postharvest life and Ca concentration of shoots. In all spray treatments, number of flowers in zero salinity was more than 1.5 dS/m treatments. In general, in case of using low-quality water (electrical conductivity of 1.5 dS/m, the effects of salinity on dry and fresh weights of gerbera plant and vase life of its flowers can be reduced by foliar application of Ca and Si. Since inappropriate water quality in Rasht Greenhouse Complex, Soume-e-Sara town, is one of the main problems of the farmers, especially in growing the ornamental plants, effects of salinity on plant growth could be alleviated with foliar spray of nutrients, especially Ca and Si. In this respect, four times spray of Ca and also twice spray of Ca + twice spray of Si are recommended.

  17. Effects of cisplatin on potassium currents in CT26 cells

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    Naveen Sharma

    2016-01-01

    Conclusion: Potassium currents were detected in CT26 cells and the currents were reduced by the application of tetraethylammonium (TEA chloride, iberiotoxin, a big conductance calcium-activated potassium channel blocker and barium. The potassium currents were enhanced to 192< by the application of cisplatin (0.5 mM. Moreover, the increase of potassium currents by cisplatin was further inhibited by the application of TEA confirming the action of cisplatin on potassium channels. In addition, relative current induced by cisplatin in CT26 cells was bit larger than in normal IEC-6 cells.

  18. Serum potassium concentrations: Importance of normokalaemia.

    Science.gov (United States)

    Heras, Manuel; Fernández-Reyes, María José

    2017-06-21

    Abnormalities in potassium concentrations are associated with morbidity and mortality. In recent years it has been considered that small variations in serum potassium concentrations within normal intervals may also be associated with mortality. Strategies for achieving normokalaemia include dietary measures, limiting the use of potassium retaining drugs, and use of conventional cation exchange resins (calcium/sodium polystyrene sulfonate) and/or the new non-absorbed cation exchange polymer (patiromer). Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  19. Hemograma, sódio, potássio, cálcio, osmolalidade e viscosidade durante angiocardiografia pediátrica com ioxaglato Blood cell count, sodium, potassium, calcium, osmolality and viscosity, during pediatric angiocardiography with ioxaglate

    Directory of Open Access Journals (Sweden)

    Mauro Regis Silva Moura

    1998-04-01

    Full Text Available OBJETIVO: Os meios de contraste (MC introduzem alterações em alguns parâmetros sangüíneos, adquirindo, assim, mais importância na angiocardiografia pediátrica. MÉTODOS: Estudamos a presença e a severidade das mudanças no hematócrito, hemoglobina, leucócitos, sódio, potássio, cálcio, osmolalidade e viscosidade, em 35 crianças submetidas a angiocardiografia com ioxaglato, identificando, também, as variáveis independentes responsáveis por essas alterações. As amostras sangüíneas foram colhidas no início do procedimento (S1, no fim (S2 e 2h após (S3. RESULTADOS: Hematócrito: S1= 47,3±6,9%; S2= 40,7±7,4% (pPURPOSE: Children's blood changes during angiocardiography may not be only due to the contrast media (CM. METHODS: We studied the presence and severity of changes in those parameters in 35 pediatric patients undergoing angiocardiography with ioxaglate aiming to identify independent variables responsible for those changes. Blood samples were taken at the beginning of the procedure (S1, at the end (S2 and two hours later (S3. RESULTS: Hematocrit: S1= 47.3±6.9%; S2= 40.7± 7.4% (p<0.001, (related to the CM volume r=0.37, p<0.05. Hemoglobin: S1= 15±2.1g%; S2= 13.2±2.4g% (p<0.001, and S3= 12.7±2.5g% (NS. White blood cell count: S1= 7940±3040 leukocytes/mm³; S2= 6950± 2700/mm³ (NS; S3= 10830±4690 leukocytes/mm³, (p<0.001. Procedure duration (r=0.38, p<0.05 and 5% glucose fluid given between S2 and S3 (r=0.49, p<0.05 were isolated. Sodium: S1= 134.5±0.4mEq/L; S2= 130.7±0.4mEq/L (p<0.001 (due to 5% glucose fluid injected, r=0.61, p<0.01. Potassium: S1= 4.22±0.45mEq/L, S2= 3.83±0.4mEq/L (p<0.001. Calcium: S1= 9.13± 1.03mg%; S2= 8.4±0.91mg/dL. (related to the CM, r=0.43, p<0.01. Osmolality: S1= 293.3±12.5mOsm/kg; S2= 300.6±13.3mOsm/kg (p<0.001. Viscosity: S1= 3.36±0.81; S2= 3.09±0.74 (p<0.01; S3= 3.87±0.89, p<0.001. There was an indirect linear regression with the CM. CONCLUSION: There were profound

  20. 猪场废水灌溉对地下水中钾、钙、钠、镁含量的影响%Influence of Livestock Wastewater Irrigation on Potassium,Calcium,Sodium and Magnesium Contents in Groundwater

    Institute of Scientific and Technical Information of China (English)

    赵君怡; 张克强; 王风; 刘鸣达

    2011-01-01

    Three volumes of anaerobic water and the output of three stages of livestock wastewater treatment mixed with groundwater were used as irrigation water three years in the area where maize-wheat rotated.As the monitoring of potassium,calcium,sodium,magnesium concentration in groundwater,the results showed that:(1)The change trends of potassium concentration in groundwater with different volume of anaerobic wastewater was HaMaLa,with the three tragedy of livestock wastewater treatment mixed with groundwater,the tendency of potassium concentration in groundwater was TagTogTeg;(2)The change trends of other three ions concentration in groundwater was LaMaHa with different volume of anaerobic wastewater and TegTogTag with the three stages of livestock wastewater treatment mixed with groundwater.%应用猪场废水处理工程中产出的厌氧水不同灌溉量和3个处理阶段出水与地下水按体积比1∶5混合对冬小麦-夏玉米轮作系统进行3年的小区灌溉试验,监测地下水的总矿化度及钾、钙、钠、镁等含量的变化。结果表明:(1)地下水中钾含量在厌氧水不同灌溉量条件下呈现高量厌氧水(Ha)〉中量厌氧水(Ma)〉低量厌氧水(La)的变化趋势,在混水灌溉处理地下水中钾含量均呈厌氧水与地下水1∶5混合(Tag)〉原水与地下水1∶5混合(Tog)〉仿生态塘水与地下水1∶5混合(Teg)的变化趋势;(2)地下水中钠、钙、镁含量大致呈现低量厌氧水(La)〉中量厌氧水(Ma)〉高量厌氧水(Ha),仿生态塘水与地下水1∶5混合(Teg)〉原水与地下水1∶5混合(Tog)〉厌氧水与地下水1∶5混合(Tag)的变化趋势。

  1. Effect of sodium, potassium, magnesium, and calcium salt cations on pH, proteolysis, organic acids, and microbial populations during storage of full-fat Cheddar cheese.

    Science.gov (United States)

    McMahon, D J; Oberg, C J; Drake, M A; Farkye, N; Moyes, L V; Arnold, M R; Ganesan, B; Steele, J; Broadbent, J R

    2014-01-01

    Sodium reduction in cheese can assist in reducing overall dietary Na intake, yet saltiness is an important aspect of cheese flavor. Our objective was to evaluate the effect of partial substitution of Na with K on survival of lactic acid bacteria (LAB) and nonstarter LAB (NSLAB), pH, organic acid production, and extent of proteolysis as water-soluble nitrogen (WSN) and protein profiles using urea-PAGE, in Cheddar cheese during 9mo of storage. Seven Cheddar cheeses with molar salt contents equivalent to 1.7% salt but with different ratios of Na, K, Ca, and Mg cations were manufactured as well as a low-salt cheese with 0.7% salt. The 1.7% salt cheeses had a mean composition of 352g of moisture/kg, 259g of protein/kg and 50% fat-on-dry-basis, and 17.5g of salt/kg (measured as Cl(-)). After salting, a faster initial decrease in cheese pH occurred with low salt or K substitution and it remained lower throughout storage. No difference in intact casein levels or percentage WSN levels between the various cheeses was observed, with the percentage WSN increasing from 5% at d 1 to 25% at 9mo. A greater decrease in intact αs1-casein than β-casein was detected, and the ratio of αs1-casein (f121-199) to αs1-casein could be used as an index of ripening. Typical changes in bacteria microflora occurred during storage, with lactococci decreasing gradually and NSLAB increasing. Lowering the Na content, even with K replacement, extended the crossover time when NSLAB became dominant. The crossover time was 4.5mo for the control cheese and was delayed to 5.2, 6.0, 6.1, and 6.2mo for cheeses with 10, 25, 50, and 75% K substitution. Including 10% Mg or Ca, along with 40% K, further increased crossover time, whereas the longest crossover time (7.3mo) was for low-salt cheese. By 9mo, NSLAB levels in all cheeses had increased from initial levels of ≤10(2) to approximately 10(6)cfu/g. Lactococci remained at 10(6) cfu/g in the low-salt cheese even after 9mo of storage. The propionic acid

  2. High potassium level

    Science.gov (United States)

    Hyperkalemia; Potassium - high; High blood potassium ... There are often no symptoms with a high level of potassium. When symptoms do occur, they may include: Nausea Slow, weak, or irregular pulse Sudden collapse, when the heartbeat gets too ...

  3. Scientific Opinion on the safety and efficacy of iodine compounds (E2 as feed additives for all species: calcium iodate anhydrous and potassium iodide, based on a dossier submitted by HELM AG

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-02-01

    Full Text Available Calcium iodate anhydrous and potassium iodide are considered safe sources of iodine for all animal species/categories when used up to the currently authorised maximum content of total iodine in complete feed, with the exception of horses and dogs, for which maximum tolerated levels are 3 and 4 mg I/kg complete feed, respectively. The limited data available on iodine tolerance in cats support a provisional tolerated level of 5 mg I/kg complete feed. Exposure of consumers was calculated in two scenarios applying the currently authorised maximum iodine contents in feed and reduced contents. The iodine content of food of animal origin, if produced taking account of the currently authorised maximum content of iodine in feed, would represent a substantial risk to high consumers. The risk would originate primarily from the consumption of milk and to a minor extent from eggs. The UL for adults (600 µg/day and for toddlers (200 µg/day would be exceeded by a factor of 2 and  4, respectively. If the authorised maximum iodine in feed for dairy cows and laying hens were reduced to 2 and 3 mg I/kg feed, respectively, the exposure of adult consumers would be below the UL. However, iodine intake in high-consuming toddlers would remain above the UL (1.6-fold. The additives are considered as irritant to the eyes, skin and respiratory tract, and as dermal sensitisers. Exposure by inhalation should be avoided. The use of the additives in animal nutrition is not expected to pose a risk to the environment. The additives are efficacious to meet animal iodine requirements. The FEEDAP Panel recommends that the maximum iodine contents in complete feed be reduced as follows: dairy cows and minor dairy ruminants, 2 mg I/kg; laying hens, 3 mg I/kg; horses, 3 mg I/kg; dogs, 4 mg I/kg; cats, 5 mg I/kg.

  4. ICP-OES法同时测定燕麦片中的钾、钠、钙、镁、铁、锌%Simultaneous determination of potassium, sodium, calcium, magnesium, iron, zinc in oatmeal with ICP-OES

    Institute of Scientific and Technical Information of China (English)

    孙丽萍; 张素娟; 梁宝爱

    2015-01-01

    The determination method of potassium, sodium, calcium, magnesium, iron, zinc in oatmeal was established by the optimization of ICP-AES instruments conditions, with three different digestion methods. The results show that the linear relationship of each element elements is good, the correlation coefficient is above 0.999 9, the relative standard deviation is 1.5%~3.3% and the recovery rate is 82.3%~ 109.4%. The method is operated conveniently, with high accuracy and good precision. The test results of both the method (ICP-OES) and the national standard method are consistent, with no significant difference, and suitable for determination of mineral element in oatmeal.%通过对ICP-OES仪器条件的优化,采用3种不同消解方法,建立了燕麦片中钾、钠、钙、镁、铁、锌各元素的测定方法。试验结果表明,该方法中各元素的线性关系良好,相关系数均在0.9999以上,其相对标准偏差为1.5%~3.3%,回收率为82.3%~109.4%。该方法操作便捷、准确度高、精密度好,与国标方法比较检测结果一致,无显著性差异,适用于燕麦片中矿物质元素的测定。

  5. Physicochemical action of potassium-magnesium citrate in nephrolithiasis

    Science.gov (United States)

    Pak, C. Y.; Koenig, K.; Khan, R.; Haynes, S.; Padalino, P.

    1992-01-01

    Effect of potassium-magnesium citrate on urinary biochemistry and crystallization of stone-forming salts was compared with that of potassium citrate at same dose of potassium in five normal subjects and five patients with calcium nephrolithiasis. Compared to the placebo phase, urinary pH rose significantly from 6.06 +/- 0.27 to 6.48 +/- 0.36 (mean +/- SD, p less than 0.0167) during treatment with potassium citrate (50 mEq/day for 7 days) and to 6.68 +/- 0.31 during therapy with potassium-magnesium citrate (containing 49 mEq K, 24.5 mEq Mg, and 73.5 mEq citrate per day). Urinary pH was significantly higher during potassium-magnesium citrate than during potassium citrate therapy. Thus, the amount of undissociated uric acid declined from 118 +/- 61 mg/day during the placebo phase to 68 +/- 54 mg/day during potassium citrate treatment and, more prominently, to 41 +/- 46 mg/day during potassium-magnesium citrate therapy. Urinary magnesium rose significantly from 102 +/- 25 to 146 +/- 37 mg/day during potassium-magnesium citrate therapy but not during potassium citrate therapy. Urinary citrate rose more prominently during potassium-magnesium citrate therapy (to 1027 +/- 478 mg/day from 638 +/- 252 mg/day) than during potassium citrate treatment (to 932 +/- 297 mg/day). Consequently, urinary saturation (activity product) of calcium oxalate declined significantly (from 1.49 x 10(-8) to 1.03 x 10(-8) M2) during potassium-magnesium citrate therapy and marginally (to 1.14 x 10(-8) M2) during potassium citrate therapy.(ABSTRACT TRUNCATED AT 250 WORDS).

  6. 钾通道阻断剂4-氨基吡啶诱导海马CA1锥体神经元钙瞬变%Calcium transient of CA1 pyramidal neurons induced by potassium blocker 4-aminopyridine in acute hippocampal slices

    Institute of Scientific and Technical Information of China (English)

    苏涛; 丛文东; 廖卫平

    2011-01-01

    Objective To investigate the calcium transient of CA1 pyramidal neurons induced by potassium blocker 4-aminopyridine (4-AP) in acute hippocampal slices to explore the relation between potassium channel function and calcium transient, and their mechanism. Methods Fluorescent probe was employed to mark the hippocampai neurons in acute brain slices of rats; confocal microscopy was used to perform calcium imaging to observe the influences of different concentrations of 4-AP and perfusate with/without calcium on calcium transient of CA1 pyramidal neurons. Results The response of [Ca2+]I to lower concentration of 4-AP (<15 mmol/L) was in a dose-dependent manner (r2=0.910, P=0.000); the higher the concentration of 4-AP (20-80 mmol/L), the lower the peak level of calcium transient. The latency and amplitude of calcium transient induced by 4-AP were obviously reduced when the extracellular condition was switched to an absence of calcium, which was significantly different as compared with that with calcium (P<0.05). Conclusion Blockade of potassium channels with 4-AP can increase [Ca2+]I in the hippocampal pyramidal neurons of acute slices. The increase of [Ca2+]1 to 4-AP could be ascribe to calcium release from intracellular stores and calcium influx from extracellular matrix.%目的 研究4-氨基吡啶(4-AP)诱导的急性脑片海马CA1锥体神经元钙瞬变现象,探讨钾通道功能与钙瞬变的关系及可能机制.方法 荧光探针标记正常大鼠急性脑片海马神经元.共聚焦显微镜技术进行钙成像,观察不同浓度4-AP及细胞灌流液条件对神经元钙瞬变的影响.结果 低浓度(<15 mmol/L)4-AP诱导的钙瞬变峰值与剂量呈线性相关(r2=0.910,P=0.000),高浓度(20~80 mmol/L)4-AP诱导的钙瞬变峰值随浓度增高而下降.在无钙灌流液条件下,4-AP诱导的钙瞬变峰值水平下降,达峰时间延长,与含钙灌流液比较差异有统计学意义(P<0.05).结论 4-AP可诱导急性脑片海马CA1锥体神经

  7. 断根、环割对烟草体内钾、钙、镁循环和积累的影响%Effects of the Root-cutting and Girding on the Circulation and Accumulation of the Potassium, Calcium and Magnesium in Tobacco

    Institute of Scientific and Technical Information of China (English)

    沈方科; 韦忠; 黄芩芬; 唐新莲; 尹永强; 廖曼玲; 张坚超; 顾明华

    2011-01-01

    在网室内采用水培方式栽培烟草,于烟草打顶期及打顶后一周进行断根、环割处理,探讨断根、环割及断根+环割对烟草吸收钾、钙、镁和烟株体内钾、钙、镁循环、积累的影响.结果表明:断根降低了木质部汁液单位时间的钙、镁吸收循环量及钙、镁在韧皮部的积累量,而环割处理的结论刚好相反.断根+环割显著提高了木质部汁液单位时间的钾吸收循环量和烟叶的钾积累量,提高上部叶的钾含量,降低了中、下部烟叶钙、镁的含量,因此该处理提高烟叶品质的效果最好.%The tobacco plants were cultivated under solution culture conditions in the net room, and the root cutting and girdling were implemented in topping period and the eighth days after topping. The aim was to study the effects of the root cutting treatment, girdling treatment and the root cutting combined with girdling treatment on the circulation and accumulation of the potassium, calcium and magnesium in tobacco plants. The results showed that the root cutting treatment reduced the calcium, magnesium circulation amount of the xylem sap in unit time; however, the calcium, magnesium accumulation amount of the phloem; the girdling treatment had the opposite conclusion. The root cutting combined with girdling treatment increased the potassium circulation amount of the xylem sap in the unit time and the potassium circulation amount of the tobacco leaves, improved the potassium content in upper leaves and reduced the calcium and magnesium content in the middle, lower leaves. Therefore, this treatment reflected the best effect on improving the quality of the tobacco leaves.

  8. Atividade de microrganismos solubilizadores de fosfatos na presença de nitrogênio, ferro, cálcio e potássio Phosphate solubilizing activity of microorganisms in the presence of nitrogen, iron, calcium and potassium

    Directory of Open Access Journals (Sweden)

    Germano Nunes Silva Filho

    2001-12-01

    Full Text Available A capacidade e o potencial de solubilização de 21 isolados de microrganismos solubilizadores de fosfatos (Bacillus, Pseudomonas, Enterobacteriaceae, Penicillium, Aspergillus e Paecilomyces foram avaliados em cultivos em meio de cultura Glicose-Extrato de Levedura contendo diferentes fosfatos (Ca, Al ou Fe, na presença de fontes de N (peptona, amônio e nitrato e teores de Fe, Ca e K. O crescimento e a atividade solubilizadora variaram em função do tipo de microrganismo e dos fatores nutricionais. Em relação às fontes de N, a presença de amônio favoreceu a solubilização em seis isolados; destes, três solubilizaram somente nesta fonte. O nitrato diminuiu a atividade solubilizadora, reduzindo ou inibindo a solubilização. Para a maioria dos microrganismos, a atividade solubilizadora não foi afetada pelas variações nos teores de ferro. Baixos teores de Ca e K limitaram o crescimento de cinco isolados que apresentam características de amplo crescimento (Aspergillus. Em dois desses isolados, a solubilização de fosfato de Ca foi favorecida. Variações na capacidade e no potencial de solubilização dos microrganismos, em resposta às condições do meio de cultura, indicam que o processo ocorre com eficiência variável ou sugerem a presença de diferentes mecanismos de solubilização.Twenty-one isolates of phosphate solubilizing microorganisms (Bacillus, Pseudomonas, Enterobacteriaceae, Penicillium, Aspergillus and Paecilomyces were evaluated for their solubilizing capacity and potential in broth media (Glucose-Yeast Extract amended with different types of phosphates (Ca, Al or Fe, in the presence of N sources (peptone, ammonium and nitrate as well as concentrations of Fe, Ca and potassium. Microbial growth and phosphate solubilizing activity varied according to the microorganism and the nutrient supplied. Ammonium increased solubilization activity of six isolates and three of these solubilized only in this source. Nitrate

  9. Calcium and potassium silicates and the growth of Eucalyptus grandis seedlings Aplicação de silicatos de cálcio e de potássio e o crescimento de mudas de Eucalyptus grandis

    Directory of Open Access Journals (Sweden)

    Itamar Antonio Bognola

    2011-06-01

    Full Text Available

    The use of silicate is a practice that has been frequently adopted in annual crops, although few studies have been conducted in order to verify its efficiency in forest tree species. The main objective of this research was to evaluate the effect of calcium and potassium silicates in the growth of seedlings of Eucalyptus grandis. The experiment was conducted in a greenhouse, in Alambari county, State of São Paulo. A completely randomized experimental design was adopted, with eight treatments, three replications and 25 plants per plot, maintained at the field capacity moisture level. Seedlings were planted in plastic tubes using local substrate, basic fertilization and silicates. Diameter, height and fresh and dry biomass of the seedlings were determined 150 days after silicates treatments were applied. The use of silicates either in the substrate or through foliar application, in the production of eucalypt seedlings has proven to be inadequate when the substrate presents a balanced basic composition in terms of nutrients and pH.

    doi: 10.4336/2011.pfb.31.66.83

    O uso de silicato é uma prática que vem sendo adotada com frequência em culturas anuais, muito embora poucos trabalhos tenham sido realizados com intuito de verificar sua eficiência em espécies florestais arbóreas. O objetivo principal desta pesquisa foi avaliar o efeito da aplicação de silicatos de cálcio e de potássio no crescimento de mudas de Eucalyptus grandis. O experimento foi conduzido em casa de vegetação, no Município de Alambari, SP. O delineamento usado foi inteiramente ao acaso, com oito tratamentos, três repetições e 25 plantas por parcela, sendo mantidas na umidade de capacidade de campo. As mudas foram plantadas em tubetes de plástico, utilizando substrato local, com adubação básica e silicatos. Diâmetro de colo, altura e biomassa verde e seca das mudas foram determinados 150 dias após a

  10. Facilitation of calcium-dependent potassium current.

    Science.gov (United States)

    Thompson, S H

    1994-12-01

    The activation of Ca-dependent K+ current, Ic, was studied in macropatches on the cell bodies of molluscan neurons. When a depolarizing voltage-clamp pulse was applied repeatedly, Ic facilitated in a manner that resembled the facilitation of synaptic transmitter release. Facilitation was characterized by an increase in Ic amplitude, a progressive increase in instantaneous outward current, and a decrease in utilization time. Experiments were done to investigate the mechanism responsible for Ic facilitation. Facilitation was reduced by microinjection of an exogenous Ca2+ buffer into the cytoplasm, indicating that facilitation is a Ca(2+)-dependent process. It was also reduced at elevated temperatures. Conversely, facilitation was greatly potentiated by blocking the Na/Ca exchange mechanism. It is concluded that the facilitation of Ca-dependent K+ current results from the accumulation of Ca2+ at the inner face of the membrane during the repeated activation of Ca2+ channels by depolarization. The Ca2+ indicator fluo-3 was used in fluorescence imaging experiments to measure changes in [Ca]i near the cell membrane during repeated depolarizing pulses and the interpretation of these results was aided by numerical simulations of Ca2+ accumulation, diffusion, and buffering in the peripheral cytoplasm. These experiments showed that the time course of Ic facilitation matches the time course of Ca2+ accumulation at the membrane. It was found that the strength of Ic facilitation varies among patches on the same neuron, suggesting that the accumulation of Ca2+ is not uniform along the inner surface of the membrane and that gradients in [Ca]i develop and are maintained during trains of depolarizing pulses. Potential mechanisms that may lead to local differences in Ca2+ accumulation and Ic facilitation are discussed.

  11. Potassium currents in auditory hair cells of the frog basilar papilla.

    Science.gov (United States)

    Smotherman, M S; Narins, P M

    1999-06-01

    The whole-cell patch-clamp technique was used to identify and characterize ionic currents in isolated hair cells of the leopard frog basilar papilla (BP). This end organ is responsible for encoding the upper limits of a frog's spectral sensitivity (1.25-2.0 kHz in the leopard frog). Isolated BP hair cells are the smallest hair cells in the frog auditory system, with spherical cell bodies typically less than 20 microm in diameter and exhibiting whole-cell capacitances of 4-7 pF. Hair cell zero-current resting potentials (Vz) varied around a mean of -65 mV. All hair cells possessed a non-inactivating, voltage-dependent calcium current (I(Ca)) that activates above a threshold of -55 mV. Similarly all hair cells possessed a rapidly activating, outward, calcium-dependent potassium current (I(K)(Ca)). Most hair cells also possessed a slowly activating, outward, voltage-dependent potassium current (I(K)), which is approximately 80% inactive at the hair cell Vz, and a fast-activating, inward-rectifying potassium current (I(K1)) which actively contributes to setting Vz. In a small subset of cells I(K) was replaced by a fast-inactivating, voltage-dependent potassium current (I(A)), which strongly resembled the A-current observed in hair cells of the frog sacculus and amphibian papilla. Most cells have very similar ionic currents, suggesting that the BP consists largely of one homogeneous population of hair cells. The kinetic properties of the ionic currents present (in particular the very slow I(K)) argue against electrical tuning, a specialized spectral filtering mechanism reported in the hair cells of birds, reptiles, and amphibians, as a contributor to frequency selectivity of this organ. Instead BP hair cells reflect a generalized strategy for the encoding of high-frequency auditory information in a primitive, mechanically tuned, terrestrial vertebrate auditory organ.

  12. Potassium-stimulated release of radiolabelled taurine and glycine from the isolated rat retina

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.F.; Pycock, C.J.

    1982-09-01

    The release of preloaded (/sup 3/H)glycine and (/sup 3/H)taurine in response to a depolarising stimulus (12.5-50 mM KCl) has been studied in the superfused rat retina. High external potassium concentration immediately increased the spontaneous efflux of (/sup 3/H)glycine, the effect of 50 mM K+ apparently being abolished by omitting calcium from the superfusing medium. In contrast, although high potassium concentrations increased the spontaneous efflux of (/sup 3/H)taurine from the superfused rat retina, this release was not evident until the depolarising stimulus was removed from the superfusing medium. The magnitude of this late release of (/sup 3/H)taurine was dependent on external K+ concentrations, and appeared immediately after cessation of the stimulus irrespective of whether it was applied for 4, 8, or 12 min. Potassium (50 mM)-induced release of taurine appeared partially calcium-dependent, being significantly reduced (p less than 0.01) but not abolished by replacing calcium with 1 mM EDTA in the superfusate. High-affinity uptake systems for both (/sup 3/H)glycine and (/sup 3/H)taurine were demonstrated in the rat retina in vitro (Km values, 1.67 microM and 2.97 microM; Vmax values, 19.3 and 23.1 nmol/g wet weight tissue/h, respectively). The results are discussed with respect to the possible neurotransmitter roles of both amino acids in the rat retina.

  13. The effect of a high-protein, high-sodium diet on calcium and bone metabolism in postmenopausal women stratified by hormone replacement therapy use

    DEFF Research Database (Denmark)

    Harrington, M.; Bennett, T.; Jakobsen, Jette;

    2004-01-01

    randomly assigned to a diet high in protein ( 90 g/day) and sodium (180 mmol/day) ( calciuric diet) or a diet moderate in protein ( 70 g/day) and low in sodium ( 65 mmol/day) for 4 weeks followed by crossover to alternative dietary regimen for a further 4 weeks. The calciuric diet significantly (P......The objective of this study was to investigate the influence of a high-sodium, high-protein diet on bone metabolism in postmenopausal women ( aged 49 - 60 y) stratified by hormone replacement therapy (HRT) use. In a crossover trial, 18 women (n = 8 HRT users (+HRT) and n = 10 nonusers (-HRT)) were...

  14. The effect of a high-protein, high-sodium diet on calcium and bone metabolism in postmenopausal women stratified by hormone replacement therapy use

    DEFF Research Database (Denmark)

    Harrington, M.; Bennett, T.; Jakobsen, Jette

    2004-01-01

    randomly assigned to a diet high in protein ( 90 g/day) and sodium (180 mmol/day) ( calciuric diet) or a diet moderate in protein ( 70 g/day) and low in sodium ( 65 mmol/day) for 4 weeks followed by crossover to alternative dietary regimen for a further 4 weeks. The calciuric diet significantly (P......The objective of this study was to investigate the influence of a high-sodium, high-protein diet on bone metabolism in postmenopausal women ( aged 49 - 60 y) stratified by hormone replacement therapy (HRT) use. In a crossover trial, 18 women (n = 8 HRT users (+HRT) and n = 10 nonusers (-HRT)) were...

  15. 通过控制钙和钾离子流抑制心脏中的螺旋波和时空混沌%Suppression of Spiral Waves and Spatiotemporal Chaos in Cardiac Tissues with Controll of Calcium and Potassium Ionic Currents

    Institute of Scientific and Technical Information of China (English)

    钟敏; 唐国宁

    2011-01-01

    Suppression of spiral waves and spatiotemporal chaos in cardiac tissues described by LuoRudy 91 model are studied. We suggest a control strategy which applys calcium channel agonist to enlarge maximum conductivity of calcium current, and applys potassium channel blocker to reduce maximum conductivity of potassium current, for suppression of spiral waves and spatiotemporal chaos. It shows that the method can effectively suppress spiral waves and spatiotemporal chaos even if there exist defects without function of diffusion in a medium. The control mechanism is analyzed.%采用LuoRudy91心脏模型研究螺旋波和时空混沌的控制,提出联合使用钙通道激动剂和钾通道阻滞剂的控制策略来增大钙离子电导率和减小钾离子电导率,达到消除心脏组织中的螺旋波和时空混沌的目的.数值模拟结果表明,该方法可以有效抑制螺旋波和时空混沌,即使介质存在无扩散功能的缺陷时该方法仍有效.对控制机制做简单探讨.

  16. Determination Method of Content of Calcium Ion, Magnesium Ion and Sulfate Ion in Agricultural Potassium Sulfate%农用硫酸钾中钙离子、镁离子和硫酸根离子含量的测定方法

    Institute of Scientific and Technical Information of China (English)

    郭峰

    2016-01-01

    The agricultural potassium sulfate is a common high quality potash fertilizer , which quality is related to the safety of national agricultural production .Through repeated trial and error , the determination method suitable for detecting calcium ion , magnesium ion and sulfate ion content in agricultural potassium sulfate is obtained , which can provide theoretical basis and data foundation for determination of content of these ions in agricultural potassium sulfate .%农用硫酸钾是常用的优质钾肥,其质量优劣关系着我国农业生产的安全。通过反复试验摸索,得出了适合测定硫酸钾中钙离子、镁离子和硫酸根离子含量的测定方法,以期为农用硫酸钾中这些离子含量的测定提供理论依据与数据基础。

  17. A case report: Giant cystic parathyroid adenoma presenting with parathyroid crisis after Vitamin D replacement

    Directory of Open Access Journals (Sweden)

    Asghar Ali

    2012-07-01

    Full Text Available Abstract Background Parathyroid adenoma with cystic degeneration is a rare cause of primary hyperparathyroidism. The clinical and biochemical presentation may mimic parathyroid carcinoma. Case presentation We report the case of a 55 year old lady, who had longstanding history of depression and acid peptic disease. Serum calcium eight months prior to presentation was slightly high, but she was never worked up. She was found to be Vitamin D deficient while being investigated for generalized body aches. A month after she was replaced with Vitamin D, she presented to us with parathyroid crisis. Her corrected serum calcium was 23.0 mg/dL. She had severe gastrointestinal symptoms and acute kidney injury. She had unexplained consistent hypokalemia until surgery. Neck ultrasound and CT scan revealed giant parathyroid cyst extending into the mediastinum. After initial medical management for parathyroid crisis, parathyroid cystic adenoma was surgically excised. Her serum calcium, intact parathyroid hormone, creatinine and potassium levels normalized after surgery. Conclusion This case of parathyroid crisis, with very high serum calcium and parathyroid hormone levels, is a rare presentation of parathyroid adenoma with cystic degeneration. This case also highlights that Vitamin D replacement may unmask subclinical hyperparathyroidism. Consistent hypokalemia until surgery merits research into its association with hypercalcemia.

  18. Minireview: potassium channels and aldosterone dysregulation: is primary aldosteronism a potassium channelopathy?

    Science.gov (United States)

    Gomez-Sanchez, Celso E; Oki, Kenji

    2014-01-01

    Primary aldosteronism is the most common form of secondary hypertension and has significant cardiovascular consequences. Aldosterone-producing adenomas (APAs) are responsible for half the cases of primary aldosteronism, and about half have mutations of the G protein-activated inward rectifying potassium channel Kir3.4. Under basal conditions, the adrenal zona glomerulosa cells are hyperpolarized with negative resting potentials determined by membrane permeability to K(+) mediated through various K(+) channels, including the leak K(+) channels TASK-1, TASK-3, and Twik-Related Potassium Channel 1, and G protein inward rectifying potassium channel Kir3.4. Angiotensin II decreases the activity of the leak K(+) channels and Kir3.4 channel and decreases the expression of the Kir3.4 channel, resulting in membrane depolarization, increased intracellular calcium, calcium-calmodulin pathway activation, and increased expression of cytochrome P450 aldosterone synthase (CYP11B2), the last enzyme for aldosterone production. Somatic mutations of the selectivity filter of the Kir3.4 channel in APA results in loss of selectivity for K(+) and entry of sodium, resulting in membrane depolarization, calcium mobilization, increased CYP11B2 expression, and hyperaldosteronism. Germ cell mutations cause familial hyperaldosteronism type 3, which is associated with adrenal zona glomerulosa hyperplasia, rather than adenoma. Less commonly, somatic mutations of the sodium-potassium ATPase, calcium ATPase, or the calcium channel calcium channel voltage-dependent L type alpha 1D have been found in some APAs. The regulation of aldosterone secretion is exerted to a significant degree by activation of membrane K(+) and calcium channels or pumps, so it is not surprising that the known causes of disorders of aldosterone secretion in APA have been channelopathies, which activate mechanisms that increase aldosterone synthesis.

  19. Potassium currents in isolated CA1 neurons of the rat after kindling epileptogenesis.

    Science.gov (United States)

    Vreugdenhil, M; Wadman, W J

    1995-06-01

    Daily tetanic stimulation of the Schaffer collaterals generates an epileptogenic focus in area CA1 of the rat hippocampus, ultimately leading to generalized tonic-clonic convulsions (kindling). Potassium currents were measured under voltage-clamp conditions in pyramidal neurons, acutely dissociated from the focus of fully kindled rats, one day and six weeks after the last generalized seizure. Their amplitude, kinetics, voltage dependence and calcium dependence were compared with controls. With Ca2+ influx blocked by 0.5 mM Ni2+, the sustained current (delayed rectifier) and the transient current (A-current) were not different after kindling. Calcium influx evoked an additional fast transient current component. This transient calcium-dependent current component was increased by 154%, but only immediately after the seizure. A second, slow calcium-dependent potassium current component was dependent on the intracellular calcium level, set by the pipette as well as on calcium influx. The peak amplitude of this slow calcium-dependent current was under optimal calcium conditions not different after kindling, but we found indications that either calcium homeostasis or the calcium sensitivity of the potassium channels was affected by the kindling process. In contrast to the previously described enhancement of calcium current, kindling epileptogenesis did not change the total potassium current amplitude. The minor changes that were observed can be related either to changes in calcium current or to changes in intracellular calcium homeostasis.

  20. Potassium carbonate poisoning

    Science.gov (United States)

    Potassium carbonate is a white powder used to make soap, glass, and other items. This article discusses poisoning from swallowing or breathing in potassium carbonate. This article is for information only. Do ...

  1. Potassium maldistribution revisited

    African Journals Online (AJOL)

    distributor of 15% potassium chloride has printed instructions ... maldistribution of concentrated 15% potassium chloride after injection into one-liter, flexible, ... rates should be controlled, preferably using an electronic infusion controller.

  2. 钠钾镁钙葡萄糖注射液(乐加)在急诊低血容量性休克液体复苏中的应用研究%The Application of the Emergency Hypovolemic Shock Fluid Resuscitation by Sodium, Potassium, Magnesium Calcium Glucose Injection (Lejia)

    Institute of Scientific and Technical Information of China (English)

    覃双全; 刘笋; 曾宪华; 曾景亭; 张春阳; 贺永明

    2014-01-01

    Objective To study the emergency hypovolemic shock lfuid resuscitation, sodium, potassium, magnesium, calcium process to give glucose injection methods and results. Methods July 2011 - February 2014 in our hospital emergency department patients with hypovolemic shock were 52 cases of clinical study, patients were randomly divided into two groups. Control group of 26 patients using conventional lfuid resuscitation Ringer's lactate;26 cases of patients in the experimental group, given the sodium, potassium, magnesium, calcium and glucose injection recovery, patients were compared before and after potassium treatment, sodium, calcium, magnesium equivalent; determination 1 h after resuscitation of patients in mean arterial pressure (MAP) and heart rate.Result Patients Experimental group after resuscitation 1 h, the patient's serum sodium, potassium, calcium, magnesium blood-related indicators are better than the control group of patients, the statistical analysis, P<0.05, signiifcant difference;patients in the experimental group after recovery 1h, MAP higher heart rate is relatively low, compared with the control group, P<0.05, the difference was statistically signiifcant. Conclusions Patients with hypovolemic shock emergency resuscitation sodium, potassium, magnesium, calcium given glucose injection treatment and better clinical results, helps to maintain a stable internal environment, worthy of promotion.%目的:研究急诊低血容量性休克液体复苏过程中给予钠钾镁钙葡萄糖注射液的方法和效果。方法选择2011年7月至2014年2月我院急诊低血容量性休克患者共52例为临床研究对象,将患者随机分为两组。对照组共26例,使用乳酸林格液常规液体复苏;实验组患者26例,给予钠钾镁钙葡萄糖注射液复苏,观察比较患者治疗前后的血钾、钠、钙、镁等值;测定复苏1h后患者平均动脉压(MAP)和心率。结果实验组患者在复苏1h后,患者的血钠、

  3. 驼初乳中钾、钙、钠、镁、铜、铁、锌质量浓度的检测%Detection of potassium,calcium,sodium, magnesium,copper,iron,zinc concentration in Xinjiang Bactrian milk Camel colostrum

    Institute of Scientific and Technical Information of China (English)

    苏薇; 杨洁

    2011-01-01

    为研究新疆双峰驼驼初乳中钾、钙、钠、镁、铜、铁、锌的质量浓度及其在泌乳期内的变化,采用火焰原子吸收分光光度法进行测定,回收率为92.45%~110.85%之间,相对标准偏差小于5%,说明该法具有良好的准确性和精密度.结果表明,新疆双峰驼驼初乳中钾的质量浓度最为丰富高,其次为钠、钙和镁;检测发现驼初乳中铜、铁、锌质量浓度未达到仪器最佳工作条件下的最低检出限.在泌乳期1~6d内,钙元素和镁元素质量浓度的变化有相关性,差异显著;钠元素和钙元素质量浓度的变化与泌乳天数有相关性,差异显著;钙元素质量浓度的变化与泌乳天数有相关性,差异极显著.与牛乳相比,新疆双峰驼驼初乳中含有相对较高质量浓度的钾、钙、钠、镁的质量浓度较高,饮用驼初乳可作为补充人体所需钾、钙、钠、镁元素的一种有效途径.%The content of potassium,calcium,sodium, magnesium,copper,iron,zinc in Xinjiang Bactrian camel colostrum changes in the lactation period. By flame atomic absorption spectrometry were determined,recovery was between 92.45%~110.85%, the relative standard deviation less than 5%, it showed that the method has good accuracy and precision. The concentrantion of potassium was highest in Xinjiang Bactrian camel colostrum, followed by sodium,calcium and magnesium. The concentrantion of Ccopper, iron, zinc content in camel milk does did not meet the minimum detection limit of the instrument. In lactation 1 ~6 days,calcium and magnesium concentration changes was relevant,significant difference. The concentration changes of sodium,calcium and days of lactation was relevant,significant difference. Compared with bovine milk, the concentration of potassium,calcium,sodium, magnesium are higher in Xinjiang Bactrian camel colostrum. Drinking camel milk is an effective way as a supplement of potassium,calcium,sodium,magnesium elements needed by

  4. Ankle replacement

    Science.gov (United States)

    Ankle arthroplasty - total; Total ankle arthroplasty; Endoprosthetic ankle replacement; Ankle surgery ... You may not be able to have a total ankle replacement if you have had ankle joint infections in ...

  5. Knee Replacement

    Science.gov (United States)

    Knee replacement is surgery for people with severe knee damage. Knee replacement can relieve pain and allow you to ... Your doctor may recommend it if you have knee pain and medicine and other treatments are not ...

  6. Potassium Secondary Batteries.

    Science.gov (United States)

    Eftekhari, Ali; Jian, Zelang; Ji, Xiulei

    2017-02-08

    Potassium may exhibit advantages over lithium or sodium as a charge carrier in rechargeable batteries. Analogues of Prussian blue can provide millions of cyclic voltammetric cycles in aqueous electrolyte. Potassium intercalation chemistry has recently been demonstrated compatible with both graphite and nongraphitic carbons. In addition to potassium-ion batteries, potassium-O2 (or -air) and potassium-sulfur batteries are emerging. Additionally, aqueous potassium-ion batteries also exhibit high reversibility and long cycling life. Because of potentially low cost, availability of basic materials, and intriguing electrochemical behaviors, this new class of secondary batteries is attracting much attention. This mini-review summarizes the current status, opportunities, and future challenges of potassium secondary batteries.

  7. P物质对大鼠结肠平滑肌细胞钾钙电流的影响%Effect of substance P on the potassium and calcium currents of colonic smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    唐勤彩; 罗和生; 全晓静; 樊菡; 余光

    2015-01-01

    Objective To investigate the effect of substance P(SP) on the spontaneous contractile activity of smooth muscle cells,the large-conductance calcium-activated potassium channel currents (IBKCa) and the L-type calcium channel currents (ICaL) in rat smooth muscle cells of the proximal colon.Methods A total of 24 healthy male Wista rats were used in this test.The change of smooth muscle strips spontaneous contraction of rat proximal colon after adding SP was recorded by a physiological signal stystem (RM6240).The IBKCa and ICaL were measured via the whole cell patch-clamp technique.Results The longitudinal muscle contraction was obviously increased concentration-dependently after adding different concentrations of SP (10-7-10-6 mol/L),so as the circular muscle while adding SP(10-8-10-6 mol/L) (all P < 0.05).Compared with the control group,IBKCa was decreased after adding SP(10-6mol/L).Under the stimulating voltage of 60 mY,the IBKCa current density was (11.71 ± 1.65) pA/pF,which was significantly lower compared with the control group (14.42 ± 2.89) pA/pF (P < 0.05).The ICaL was apparently increased.Under the stimulating voltage of 0 mY,the ICaL currents density was (-5.04 ± 0.67) pA/pF,compared with the control group (-4.25 ± 0.46) pA/pF,which was significantly increased (P < 0.01).Conclusions SP can promote the spontaneous contractile activity of colon smooth muscle of rats in vitro.And SP decrease IBKCa representatively while apparently increase ICaL.That is probably one of the mechanism SP regulate the gastrointestinal motility.%目的 研究P物质(SP)对大鼠近端结肠平滑肌细胞大电导钙激活钾通道电流(IBKCa)和L型钙通道电流(ICaL)的影响,探讨其促结肠动力的作用机制.方法 选取健康雄性Wistar大鼠24只,采用RM6240生理信号采集处理系统记录SP对大鼠近端结肠平滑肌肌条收缩的影响;采用全细胞膜片钳技术检测SP对近端结肠平滑肌细胞IBKCa和ICaL的影响.结果 10-7~10-6 mol

  8. 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.

  9. Connexin 43 impacts on mitochondrial potassium uptake

    Directory of Open Access Journals (Sweden)

    Kerstin eBoengler

    2013-06-01

    Full Text Available In cardiomyocytes, connexin 43 (Cx43 forms gap junctions and unopposed hemichannels at the plasma membrane, but the protein is also present at the inner membrane of subsarcolemmal mitochondria. Both inhibition and genetic ablation of Cx43 reduce ADP-stimulated complex 1 respiration. Since mitochondrial potassium influx impacts on oxygen consumption, we investigated whether or not inhibition or ablation of mitochondrial Cx43 alters mitochondrial potassium uptake.Subsarcolemmal mitochondria were isolated from rat left ventricular (LV myocardium and loaded with the potassium-sensitive dye PBFI. Intramitochondrial potassium was replaced by TEA (tetraethylammonium. Mitochondria were incubated under control conditions or treated with 250 µM Gap19, a peptide that specifically inhibits Cx43-dependent hemichannels at plasma membranes. Subsequently, 140 mM KCl was added and the slope of the increase in PBFI fluorescence over time was calculated. The slope of the PBFI fluorescence of the control mitochondria was set to 100%. In the presence of Gap19, the mitochondrial potassium influx was reduced from 100±11.6 % in control mitochondria to 65.5±10.7 % (n=6, p<0.05. In addition to the pharmacological inhibition of Cx43, potassium influx was studied in mitochondria isolated from conditional Cx43 knockout mice. Here, the ablation of Cx43 was achieved by the injection of 4-hydroxytamoxifen (Cx43Cre-ER(T/fl + 4-OHT. The mitochondria of the Cx43Cre-ER(T/fl + 4-OHT mice contained 3±1% Cx43 (n=6 of that in control mitochondria (100±11%, n=8, p<0.05. The ablation of Cx43 (n=5 reduced the velocity of the potassium influx from 100±11.2 % in control mitochondria (n=9 to 66.6±5.5 % (p<0.05.Taken together, our data indicate that both pharmacological inhibition and genetic ablation of Cx43 reduce mitochondrial potassium influx.

  10. Role of calcium conductance in firing behavior of retinal ganglion cells

    Institute of Scientific and Technical Information of China (English)

    Dan Wang; Qingli Qiao; Nan Xie

    2011-01-01

    Fohlmeister-Coleman-Miller model of retinal ganglion cells consists of five ion channels; these are sodium channels, calcium channels, and 3 types of potassium channels. An increasing number of studies have investigated sodium channels, voltage-gated potassium channels, and delayed rectifier potassium channels. However, little is known about calcium channels, and in particular the dynamics and computational models of calcium ions. Retinal prostheses have been designed to assist with sight recovery for the blind, and in the present study, the effects of calcium ions in retinal ganglion cell models were analyzed with regard to calcium channel potential and calcium-activated potassium potential. Using MATLAB software, calcium conductance and calcium current from the Fohlmeister-Coleman-Miller model, under clamped voltages, were numerically computed using backward Euler methods. Subsequently, the Fohlmeister-Coleman-Miller model was simulated with the absence of calcium-current (lc,) or calcium-activated potassium current (IK, ca). The model was also analyzed according to the phase plane method.The relationship curve between peak calcium current and clamped potentials revealed an inverted bell shape, and the calcium-activated potassium current increased the frequency of firing and the peak of membrane potential. Results suggested that calcium ion concentrations play an important role in controlling the peak and the magnitude of peak membrane voltage in retinal ganglion cells.

  11. Intractable hyperkalemia due to nicorandil induced potassium channel syndrome

    Directory of Open Access Journals (Sweden)

    Vivek Chowdhry

    2015-01-01

    Full Text Available Nicorandil is a commonly used antianginal agent, which has both nitrate-like and ATP-sensitive potassium (K ATP channel activator properties. Activation of potassium channels by nicorandil causes expulsion of potassium ions into the extracellular space leading to membrane hyperpolarization, closure of voltage-gated calcium channels and finally vasodilatation. However, on the other hand, being an activator of K ATP channel, it can expel K + ions out of the cells and can cause hyperkalemia. Here, we report a case of nicorandil induced hyperkalemia unresponsive to medical treatment in a patient with diabetic nephropathy.

  12. Nutrição de mudas de açaizeiro sob relações cálcio:potássio:sódio em solução nutritiva Nutrition of açai seedlings (Euterpe oleracea Mart. under different ratios of calcium:potassium: sodium in nutrient solution

    Directory of Open Access Journals (Sweden)

    Humberto Umbelino de Sousa

    2004-02-01

    Full Text Available Objetivando-se estudar diferentes relações entre os cátions cálcio, potássio e sódio na produção de matéria seca e acúmulo de macronutrientes em mudas de açaizeiro (Euterpe oleracea Mart., realizou-se um experimento em casa-de-vegetação no Departamento de Ciência do Solo da UFLA. Utilizou-se o delineamento estatístico em blocos casualisados com nove tratamentos em quatro repetições. Os tratamentos foram constituídos por nove relações cálcio: potássio: sódio (4:2:1, 3:3:1, 2:4:1, 1:5:1, 5:1:1, 4:1:2, 6:0:1; 0:6:1, e 4:2:0 em solução nutritiva. A unidade experimental constituiu-se de um vaso com capacidade para três litros de solução, contendo duas plantas. Avaliaram-se as seguintes características: produção de matéria seca e o acúmulo dos macronutrientes fósforo, cálcio, potássio, magnésio e enxofre na matéria seca da planta. A relação cálcio:potássio:sódio influenciou todas as características avaliadas; as soluções contendo cálcio, potássio e sódio nas relações 4:2:1 e 3:3:1 resultaram no desenvolvimento de mudas com maior produção de matéria seca e maior acúmulo de nutrientes.Aiming to evaluate the effects of different ratios of calcium, potassium and sodium cations on the mineral nutrition of açai seedlings (Euterpe oleracea Mart., a greenhouse experiment was carried out in the Soil Science Department at the Federal University of Lavras-UFLA. The randomized block design, with nine treatments and four replications, was used. The treatments were nine ratios of calcium, potassium and sodium (4:2:1, 3:3:1, 2:4:1, 1:5:1, 5:1:1, 4:1:2, 6:0:1; 0:6:1, e 4:2:0 in the nutrient solution. The experimental unit was a plastic pot with three liters of solution, containing two plants. The total dry matter and nutrient accumulation were evaluated. The relationship calcium:potassium:sodium influenced all the appraised characteristics, and the solutions containing calcium, potassium and sodium in the ratios

  13. Comparative Study of Sodium and Potassium in Different Types of Gallstones and in Serum of Subjects with Gallstones and Controls

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Soomro

    2008-06-01

    Full Text Available The study comprises evaluation of sodium and potassium in the pathogenesis of human gallstones as well as measurement of the concentration of these elements in gallstones and in sera of 109 gallstone subjects and 100 controls (age and sex matched with no personal or family history of gallstone disease. It was observed that serum concentrations for both sodium and potassium were comparable (p>0.05 between gallstone subjects and control subjects. In gallstones the concentration of sodium was significantly higher as compared to potassium (p<0.05. Normal sodium to potassium ratio was seen in serum of gallstone subjects, whereas, low sodium to potassium ratio was seen in gallstone carriers. Amongst the different types of gallstones, significantly high (p<0.05 concentrations of sodium and potassium were seen in calcium bilirubinate gallstones. The levels for these mineral elements were also raised in serum of pure calcium carbonate gallstone subjects.The results demonstrate that the higher concentration of sodium and potassium in gallstones may involve in both calcium bilirubinate gallstones and in serum of calcium carbonate gallstone subjects, which indicate their association with calcium in the precipitation of calcium bilirubinate and calcium carbonate in bile. Furthermore, low sodium to potassium ratio in gallstones indicates low ratio in bile of gallstone subjects.

  14. Directed Replacement

    CERN Document Server

    Karttunen, L

    1996-01-01

    This paper introduces to the finite-state calculus a family of directed replace operators. In contrast to the simple replace expression, UPPER -> LOWER, defined in Karttunen (ACL-95), the new directed version, UPPER @-> LOWER, yields an unambiguous transducer if the lower language consists of a single string. It transduces the input string from left to right, making only the longest possible replacement at each point. A new type of replacement expression, UPPER @-> PREFIX ... SUFFIX, yields a transducer that inserts text around strings that are instances of UPPER. The symbol ... denotes the matching part of the input which itself remains unchanged. PREFIX and SUFFIX are regular expressions describing the insertions. Expressions of the type UPPER @-> PREFIX ... SUFFIX may be used to compose a deterministic parser for a ``local grammar'' in the sense of Gross (1989). Other useful applications of directed replacement include tokenization and filtering of text streams.

  15. Activation of protein kinase C inhibits potassium currents in cultured endothelial cells.

    Science.gov (United States)

    Zhang, H; Weir, B; Daniel, E E

    1995-04-01

    The effect of protein kinase C on potassium channels in cultured endothelial cells was investigated by using whole-cell patch-clamp techniques. Activation of protein kinase C by phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-dibutyrate (PDBu), but not phorbol 12-monomyristate (PMM), an inactive analogue of phorbol esters, depressed an outward calcium-dependent potassium current. The inhibitory actions of PMA and PDBu could be reversed by the kinase inhibitor H-7. Cyclopiazonic acid, an inhibitor of the sarcoplasmic reticulum calcium pump, and LP-805, a novel vasodilator which also releases endothelium-derived relaxing factors, activated the outward calcium-dependent potassium conductance. PMA and PDBu, but not PMM, reduced the outward conductance induced by cyclopiazonic acid and LP-805. These effects of PMA and PDBu on potassium currents may be mediated either by phosphorylation of ion channels, or by decreasing intracellular calcium concentration.

  16. Potassium food supplement

    Science.gov (United States)

    Bourland, C. T.; Huber, C. S.; Rambaut, C.; Heidelbaugh, N. D.

    1973-01-01

    Potassium gluconate is considered best supplementary source for potassium. Gluconate consistently received highest taste rating and was indistinguishable from nonsupplemented samples. No unfavorable side effects were found during use, and none are reported in literature. Gluconate is normal intermediary metabolite that is readily adsorbed and produces no evidence of gastrointestinal ulcerations.

  17. Penicillin V Potassium Oral

    Science.gov (United States)

    V-Cillin K® ... Penicillin V potassium is an antibiotic used to treat certain infections caused by bacteria such as pneumonia, scarlet fever, ... Penicillin V potassium comes as a tablet and liquid to take by mouth. It is usually taken every 6 ...

  18. Dietary Impact of Adding Potassium Chloride to Foods as a Sodium Reduction Technique

    Directory of Open Access Journals (Sweden)

    Leo van Buren

    2016-04-01

    Full Text Available Potassium chloride is a leading reformulation technology for reducing sodium in food products. As, globally, sodium intake exceeds guidelines, this technology is beneficial; however, its potential impact on potassium intake is unknown. Therefore, a modeling study was conducted using Dutch National Food Survey data to examine the dietary impact of reformulation (n = 2106. Product-specific sodium criteria, to enable a maximum daily sodium chloride intake of 5 grams/day, were applied to all foods consumed in the survey. The impact of replacing 20%, 50% and 100% of sodium chloride from each product with potassium chloride was modeled. At baseline median, potassium intake was 3334 mg/day. An increase in the median intake of potassium of 453 mg/day was seen when a 20% replacement was applied, 674 mg/day with a 50% replacement scenario and 733 mg/day with a 100% replacement scenario. Reformulation had the largest impact on: bread, processed fruit and vegetables, snacks and processed meat. Replacement of sodium chloride by potassium chloride, particularly in key contributing product groups, would result in better compliance to potassium intake guidelines (3510 mg/day. Moreover, it could be considered safe for the general adult population, as intake remains compliant with EFSA guidelines. Based on current modeling potassium chloride presents as a valuable, safe replacer for sodium chloride in food products.

  19. Knee Replacement

    Science.gov (United States)

    ... need knee replacement surgery usually have problems walking, climbing stairs, and getting in and out of chairs. Some ... a total living space on one floor since climbing stairs can be difficult. Install safety bars or a ...

  20. Replacing penalties

    Directory of Open Access Journals (Sweden)

    Vitaly Stepashin

    2017-01-01

    Full Text Available УДК 343.24The subject. The article deals with the problem of the use of "substitute" penalties.The purpose of the article is to identify criminal and legal criteria for: selecting the replacement punishment; proportionality replacement leave punishment to others (the formalization of replacement; actually increasing the punishment (worsening of legal situation of the convicted.Methodology.The author uses the method of analysis and synthesis, formal legal method.Results. Replacing the punishment more severe as a result of malicious evasion from serving accused designated penalty requires the optimization of the following areas: 1 the selection of a substitute punishment; 2 replacement of proportionality is serving a sentence other (formalization of replacement; 3 ensuring the actual toughening penalties (deterioration of the legal status of the convict. It is important that the first two requirements pro-vide savings of repression in the implementation of the replacement of one form of punishment to others.Replacement of punishment on their own do not have any specifics. However, it is necessary to compare them with the contents of the punishment, which the convict from serving maliciously evaded. First, substitute the punishment should assume a more significant range of restrictions and deprivation of certain rights of the convict. Second, the perfor-mance characteristics of order substitute the punishment should assume guarantee imple-mentation of the new measures.With regard to replacing all forms of punishment are set significant limitations in the application that, in some cases, eliminates the possibility of replacement of the sentence, from serving where there has been willful evasion, a stricter measure of state coercion. It is important in the context of the topic and the possibility of a sentence of imprisonment as a substitute punishment in cases where the original purpose of the strict measures excluded. It is noteworthy that the

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

    Science.gov (United States)

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

    1996-02-01

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

  2. KV7 potassium channels

    DEFF Research Database (Denmark)

    Stott, Jennifer B; Jepps, Thomas Andrew; Greenwood, Iain A

    2014-01-01

    identified as being crucial mediators of this process in a variety of smooth muscle. Recently, KV7 channels have been shown to be involved in the pathogenesis of hypertension, as well as being implicated in other smooth muscle disorders, providing a new and inviting target for smooth muscle disorders.......Potassium channels are key regulators of smooth muscle tone, with increases in activity resulting in hyperpolarisation of the cell membrane, which acts to oppose vasoconstriction. Several potassium channels exist within smooth muscle, but the KV7 family of voltage-gated potassium channels have been...

  3. Hypoparathyroidism: Replacement Therapy with Parathyroid Hormone

    Directory of Open Access Journals (Sweden)

    Lars Rejnmark

    2015-12-01

    Full Text Available Hypoparathyroidism (HypoPT is characterized by low serum calcium levels caused by an insufficient secretion of parathyroid hormone (PTH. Despite normalization of serum calcium levels by treatment with activated vitamin D analogues and calcium supplementation, patients are suffering from impaired quality of life (QoL and are at increased risk of a number of comorbidities. Thus, despite normalization of calcium levels in response to conventional therapy, this should only be considered as an apparent normalization, as patients are suffering from a number of complications and calcium-phosphate homeostasis is not normalized in a physiological manner. In a number of recent studies, replacement therapy with recombinant human PTH (rhPTH(1-84 as well as therapy with the N-terminal PTH fragment (rhPTH(1-34 have been investigated. Both drugs have been shown to normalize serum calcium while reducing needs for activated vitamin D and calcium supplements. However, once a day injections cause large fluctuations in serum calcium. Twice a day injections diminish fluctuations, but don't restore the normal physiology of calcium homeostasis. Recent studies using pump-delivery have shown promising results on maintaining normocalcemia with minimal fluctuations in calcium levels. Further studies are needed to determine whether this may improve QoL and lower risk of complications. Such data are needed before replacement with the missing hormone can be recommended as standard therapy.

  4. Dendritic potassium channels in hippocampal pyramidal neurons.

    Science.gov (United States)

    Johnston, D; Hoffman, D A; Magee, J C; Poolos, N P; Watanabe, S; Colbert, C M; Migliore, M

    2000-05-15

    Potassium channels located in the dendrites of hippocampal CA1 pyramidal neurons control the shape and amplitude of back-propagating action potentials, the amplitude of excitatory postsynaptic potentials and dendritic excitability. Non-uniform gradients in the distribution of potassium channels in the dendrites make the dendritic electrical properties markedly different from those found in the soma. For example, the influence of a fast, calcium-dependent potassium current on action potential repolarization is progressively reduced in the first 150 micrometer of the apical dendrites, so that action potentials recorded farther than 200 micrometer from the soma have no fast after-hyperpolarization and are wider than those in the soma. The peak amplitude of back-propagating action potentials is also progressively reduced in the dendrites because of the increasing density of a transient potassium channel with distance from the soma. The activation of this channel can be reduced by the activity of a number of protein kinases as well as by prior depolarization. The depolarization from excitatory postsynaptic potentials (EPSPs) can inactivate these A-type K+ channels and thus lead to an increase in the amplitude of dendritic action potentials, provided the EPSP and the action potentials occur within the appropriate time window. This time window could be in the order of 15 ms and may play a role in long-term potentiation induced by pairing EPSPs and back-propagating action potentials.

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

    DEFF Research Database (Denmark)

    Knudsen, Torben; Johansen, Torben

    1989-01-01

    1. Pure populations of rat peritoneal mast cells were used to study cellular potassium uptake. The radioactive potassium analogue, 86rubidium, was used as a tracer for potassium for measurements of the activity of the cellular potassium uptake process. 2. The ouabain-sensitive and the ouabain...... was decreased by reintroduction of calcium into the cell suspension, and it was dependent on cellular energy metabolism, temperature and pH. 4. The potassium (86rubidium) uptake of mast cells incubated in a calcium-free medium occurs through an active and ouabain-sensitive mechanism that has the nature...

  6. Esophageal replacement.

    Science.gov (United States)

    Kunisaki, Shaun M; Coran, Arnold G

    2017-04-01

    This article focuses on esophageal replacement as a surgical option for pediatric patients with end-stage esophageal disease. While it is obvious that the patient׳s own esophagus is the best esophagus, persisting with attempts to retain a native esophagus with no function and at all costs are futile and usually detrimental to the overall well-being of the child. In such cases, the esophagus should be abandoned, and the appropriate esophageal replacement is chosen for definitive reconstruction. We review the various types of conduits used for esophageal replacement and discuss the unique advantages and disadvantages that are relevant for clinical decision-making. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Potassium in diet

    Science.gov (United States)

    ... pills) to treat high blood pressure or heart failure Take too many laxatives Have severe or prolonged vomiting and diarrhea Have certain kidney or adrenal gland disorders Too much potassium in the blood ...

  8. [Effects of different potassium fertilizer application periods on the yield and quality of Fuji apple].

    Science.gov (United States)

    Lu, Yong-li; Yang, Xian-long; Li, Ru; Li, Shui-li; Tong, Yan-an

    2015-04-01

    In order to ascertain the effects of potassium fertilizer application periods on apple production, we conducted a field experiment and analyzed the differences in apple yield, fruit quality, potassium fertilizer use efficiency, and nutrient concentrations in leaves and fruits among treatments with differences in timing of potassium application. The results indicated that, compared with no potassium-applied treatment (CK), all potassium fertilizer application treatments significantly increased the apple yield by 4.3%-33.2%, meanwhile, it also obviously improved the fruit quality. In comparison with the application of 100% potassium fertilizer as a base, the application of 50% or 100% of potassium fertilizer at the fruit enlargement stage (the remaining 50% applied as a base or after flowering) significantly increased the apple yield by 20.5% - 27.7% and improved the fruit quality. Compared with the application 100% potassium fertilizer at the stage of fruit enlargement, the evenly split application as base flowering stage and at the fruit enlargement: stage not only contributed to a higher yield, better quality and higher potassium use efficiency, but also maintained a relatively stable potassium concentration level in leaves. However, the split potassium fertilizer application at the flowering and fruit enlargement stages resulted in the significant decrease in concentration of calcium in fruit, which would be negative to fruit quality. In conclusion, our research suggested that evenly split application of potassium fertilizer as a base and at the fruit enlargement stage was the suitable period for apple production in Fuji apple orchards in this region.

  9. 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......)-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers...

  10. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Science.gov (United States)

    2010-07-01

    ...-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... identified as D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium...

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

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-hui; ZHOU Wei

    2004-01-01

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

  12. Dehydration of α-Calcium Sulfate Hemihydrate in Potassium Chloride Solutions Under Atmospheric Pressure%常压KCl溶液中α-半水石膏的脱水过程

    Institute of Scientific and Technical Information of China (English)

    马宪法; 官宝红

    2009-01-01

    一般认为,在盐溶液中,亚稳态的α-半水石膏(α-Hemi-hydrated gypgsum,α-Hh9脱水转变为无水石膏(calcium sulfate anhydrite,AH)是直接脱水的过程.研究常压、80~102℃条件下 KCl溶液中α-HH的脱水行为,通过热分析和物相测定阐明α-HH的脱水过程和产物.结果表明KCl溶液中α-HH的脱水过程有2个相转化途径:一个是α-半水石膏→二水石膏(calcium sulfate dihydrate,DH→无水石膏(α→DH→AH)历程;另一个是α-半水石膏→无水石膏(α-HH→AH)历程.α-HH脱水转化为无水石膏的过程伴随有钾石膏的生成.α-HH在KCl溶液中的脱水速率和脱水途径取决于KCl浓度和反应温度.

  13. Nutritional potassium requirement for laying Japanese quails

    Directory of Open Access Journals (Sweden)

    Fernando Guilherme Perazzo Costa

    2011-12-01

    Full Text Available The objective of this study was to evaluate the potassium requirement for laying Japanese quails. Two hundred and forty quails were distributed in a randomized block design, with five treatments and six replicates, with eight birds each. The treatments consisted of a basal diet deficient in potassium (K (2.50 g/kg, supplemented with potassium carbonate, to replace the inert, to reach levels of 2.50, 3.50, 4.50, 5.50 and 6.50 (g/kg of K in the diet. There was a quadratic effect of K levels on feed intake, egg production, egg mass and feed conversion per egg mass and per egg dozen, estimating the requirements of 4.26, 4.41, 4.38, 4.43 and 4.48 (g/kg of K diet, respectively. There was no significant effect on the levels of K in the diet on egg weight, albumen weight, percentage of yolk or shell and yolk color. However, yolk and shell weights reduced and the albumen percentage increased linearly with increasing levels of K in the diet. Despite the reduction of shell weight, the increased levels of K did not influence the specific gravity and shell thickness. The use of 4.41 g/kg of potassium is recommended in the diet for laying Japanese quails.

  14. Implementation and evaluation of a nurse-centered computerized potassium regulation protocol in the intensive care unit - a before and after analysis

    Directory of Open Access Journals (Sweden)

    van der Horst Iwan CC

    2010-01-01

    Full Text Available Abstract Background Potassium disorders can cause major complications and must be avoided in critically ill patients. Regulation of potassium in the intensive care unit (ICU requires potassium administration with frequent blood potassium measurements and subsequent adjustments of the amount of potassium administrated. The use of a potassium replacement protocol can improve potassium regulation. For safety and efficiency, computerized protocols appear to be superior over paper protocols. The aim of this study was to evaluate if a computerized potassium regulation protocol in the ICU improved potassium regulation. Methods In our surgical ICU (12 beds and cardiothoracic ICU (14 beds at a tertiary academic center, we implemented a nurse-centered computerized potassium protocol integrated with the pre-existent glucose control program called GRIP (Glucose Regulation in Intensive Care patients. Before implementation of the computerized protocol, potassium replacement was physician-driven. Potassium was delivered continuously either by central venous catheter or by gastric, duodenal or jejunal tube. After every potassium measurement, nurses received a recommendation for the potassium administration rate and the time to the next measurement. In this before-after study we evaluated potassium regulation with GRIP. The attitude of the nursing staff towards potassium regulation with computer support was measured with questionnaires. Results The patient cohort consisted of 775 patients before and 1435 after the implementation of computerized potassium control. The number of patients with hypokalemia (5.0 mmol/L were recorded, as well as the time course of potassium levels after ICU admission. The incidence of hypokalemia and hyperkalemia was calculated. Median potassium-levels were similar in both study periods, but the level of potassium control improved: the incidence of hypokalemia decreased from 2.4% to 1.7% (P Conclusions Computerized potassium control

  15. 以尿钙排泄量为效应指标评价枸橼酸氢钾钠颗粒人体生物等效性%Evaluation of the bioequivalence of domestic and imported Potassium Sodium Hydrogen Citrate Granules with accumulative urinary excretion of calcium as index in healthy volunteers

    Institute of Scientific and Technical Information of China (English)

    张华; 刘沙; 李荣; 王本杰; 郭瑞臣

    2014-01-01

    Objective To evaluate the bioequivalence of imported and domestic Potassium Sodium Hydrogen Citrate Granules with accumulative urinary excretion of calcium as index in Chinese healthy volunteers. Methods Thirty - six healthy male volunteers were randomLy administered with a oral single dose of 5. 0 g domestic(test)and imported(refer-ence)Potassium Sodium Hydrogen Citrate Granules in a crossover study with a washout period of 7 days. Urine was collect-ed before or after oral doses at the scheduled time(0 ~ 2,2 ~ 4,4 ~ 6,6 ~ 8,8 ~ 10,10 ~ 12,12 ~ 24 h). Urine volumes were recorded,urinary calcium concentration was determined by atomic absorption spectrophotometric and twenty - four hours of accumulative urinary excretion of calcium were calculated. Results Twenty - four hours of accumulative urinary excretion of calcium were(128. 47 ± 76. 45)mg and(163. 53 ± 81. 28)mg before and after taking test preparation;(128. 34 ± 59. 55)mg and(179. 65 ± 103. 96)mg before and after taking reference preparation,respectively. Increase in 24 h urinary excretion of calcium after taking test and reference preparation were(35. 06 ± 61. 26)mg and(51. 31 ± 73. 18)mg,respec-tively. There was no significant difference(P ﹥ 0. 05)in increase of 24 h accumulative urinary excretion of calcium between the two preparations. Conclusion The domestic and imported Potassium Sodium Hydrogen Citrate Granules were bioequiv-alent.%目的:以24 h 尿液钙离子累计排泄量为指标,比较国产和进口枸橼酸氢钾钠颗粒剂的生物等效性。方法36名男性健康志愿者按自身交叉设计,随机口服枸橼酸氢钾钠颗粒剂的受试制剂(国产)或参比制剂(进口)5.0 g,(洗脱期7 d)。分别收集给药前(空白)和给药后0~2、2~4、4~6、6~8、8~10,10~12、12~24 h 的尿液,记录尿量,采用原子吸收分光光度法测定尿液钙离子浓度,计算给药前、后24 h 尿液钙累积排泄量。结

  16. A novel potassium channel in skeletal muscle mitochondria.

    Science.gov (United States)

    Skalska, Jolanta; Piwońska, Marta; Wyroba, Elzbieta; Surmacz, Liliana; Wieczorek, Rafal; Koszela-Piotrowska, Izabela; Zielińska, Joanna; Bednarczyk, Piotr; Dołowy, Krzysztof; Wilczynski, Grzegorz M; Szewczyk, Adam; Kunz, Wolfram S

    2008-01-01

    In this work we provide evidence for the potential presence of a potassium channel in skeletal muscle mitochondria. In isolated rat skeletal muscle mitochondria, Ca(2+) was able to depolarize the mitochondrial inner membrane and stimulate respiration in a strictly potassium-dependent manner. These potassium-specific effects of Ca(2+) were completely abolished by 200 nM charybdotoxin or 50 nM iberiotoxin, which are well-known inhibitors of large conductance, calcium-activated potassium channels (BK(Ca) channel). Furthermore, NS1619, a BK(Ca)-channel opener, mimicked the potassium-specific effects of calcium on respiration and mitochondrial membrane potential. In agreement with these functional data, light and electron microscopy, planar lipid bilayer reconstruction and immunological studies identified the BK(Ca) channel to be preferentially located in the inner mitochondrial membrane of rat skeletal muscle fibers. We propose that activation of mitochondrial K(+) transport by opening of the BK(Ca) channel may be important for myoprotection since the channel opener NS1619 protected the myoblast cell line C2C12 against oxidative injury.

  17. Transmission spectra study of sulfate substituted potassium dihydrogen phosphate

    KAUST Repository

    LI, LIANG

    2013-04-18

    Potassium dihydrogen phosphate (KDP) crystals with different amounts of sulfate concentration were grown and the transmittance spectrum was studied. A crystal with high sulfate replacement density exhibits heavy absorption property in the ultraviolet region which confirms and agrees well with former results. © 2013 Astro Ltd.

  18. Inhibition of growth and metabolism of Chlorella and some other plant types by calcium dipicrylamine and other poisons

    NARCIS (Netherlands)

    Bierhuizen, J.F.

    1957-01-01

    If potassium is obtained from sea-water by precipitation with calcium dipicrylamine, potassium fertilizers and sea-water will be contaminated with a little dipicrylamine. The influence of calcium dipicrylamine on metabolism of Chlorella and some other aquatic and terrestrial plants was

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

    DEFF Research Database (Denmark)

    Knudsen, T; Ferjan, I; Johansen, Torben

    1993-01-01

    Rat peritoneal mast cells were used to study the effects of digitalis glycosides on potassium uptake and histamine release induced by compound 48/80, substance P and egg-albumin (immunological release). In the absence of calcium all glycosides inhibited potassium uptake. Ouabain and digoxin...

  20. Effects of Foliar Spraying of Magnesium-potassium Sulfate Fertilizer on Absorption of Magnesium, Potassium and Calcium in Different-position Tobacco Leaves%叶面喷施硫酸钾镁肥对不同部位烟叶镁、钾、钙吸收的影响

    Institute of Scientific and Technical Information of China (English)

    周敏; 周绍松; 郑波; 鲁耀; 段宗颜; 王建新; 张忠武; 杨景华

    2014-01-01

    design were adopted in this research. The group without Mg fertilization was treated as control. There were 3 treatment groups for foliar spraying of magnesium-potassium sulfate fertilizer and 2 treatment groups for soil application + foliar spraying of magnesium-potassium sulfate fertilizer. The tobac-co roots, stems, lower leaves, middle leaves and upper leaves were dried and weighed. They were grinded for the determination of K, Ca and Mg content. The total K, Ca and Mg content in upper (B2F), middle (C3F) and lower (X2F) flue-cured tobacco leaves in each plot was measured. [Result] The foliar spraying and soil application + foliar spraying al increased the absorption of Mg and K in middle and lower tobacco leaves and the absorption of Ca in lower tobacco leaves, but de-creased the absorption of Mg, K and Ca in upper leaves and the absorption of Ca in middle leaves. Among the positions, the accumulated distribution of Mg, K and Ca ranked as middle leaves > lower leaves > upper leaves. With the application of Mg fertilizer, the Ca/Mg ratio and K/Mg ratio al decreased in middle and upper to-bacco leaves; while the Ca/Mg ratio increased in the lower tobacco leaves, and the K/Mg ratio showed no significant difference among treatment groups. [Conclusion] The foliar spraying and soil application + foliar spraying of magnesium-potassium sulfate fertilizer affected the Ca/Mg ratio and K/Mg ratio in tobacco leaves mainly through affecting the absorption of Mg.

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

    Directory of Open Access Journals (Sweden)

    Saraiva R.M.

    1997-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Pham Minh, Doan, E-mail: doan.phamminh@mines-albi.fr [Universite de Toulouse, Mines Albi, CNRS, Centre RAPSODEE, Campus Jarlard, F-81013 Albi cedex 09 (France); Lyczko, Nathalie; Sebei, Haroun; Nzihou, Ange [Universite de Toulouse, Mines Albi, CNRS, Centre RAPSODEE, Campus Jarlard, F-81013 Albi cedex 09 (France); Sharrock, Patrick [Universite de Toulouse, SIMAD, IUT Paul Sabatier, Avenue Georges Pompidou, 81104 Castres (France)

    2012-08-01

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

  3. Glucose stimulates calcium-activated chloride secretion in small intestinal cells.

    Science.gov (United States)

    Yin, Liangjie; Vijaygopal, Pooja; MacGregor, Gordon G; Menon, Rejeesh; Ranganathan, Perungavur; Prabhakaran, Sreekala; Zhang, Lurong; Zhang, Mei; Binder, Henry J; Okunieff, Paul; Vidyasagar, Sadasivan

    2014-04-01

    The sodium-coupled glucose transporter-1 (SGLT1)-based oral rehydration solution (ORS) used in the management of acute diarrhea does not substantially reduce stool output, despite the fact that glucose stimulates the absorption of sodium and water. To explain this phenomenon, we investigated the possibility that glucose might also stimulate anion secretion. Transepithelial electrical measurements and isotope flux measurements in Ussing chambers were used to study the effect of glucose on active chloride and fluid secretion in mouse small intestinal cells and human Caco-2 cells. Confocal fluorescence laser microscopy and immunohistochemistry measured intracellular changes in calcium, sodium-glucose linked transporter, and calcium-activated chloride channel (anoctamin 1) expression. In addition to enhancing active sodium absorption, glucose increased intracellular calcium and stimulated electrogenic chloride secretion. Calcium imaging studies showed increased intracellular calcium when intestinal cells were exposed to glucose. Niflumic acid, but not glibenclamide, inhibited glucose-stimulated chloride secretion in mouse small intestines and in Caco-2 cells. Glucose-stimulated chloride secretion was not seen in ileal tissues incubated with the intracellular calcium chelater BAPTA-AM and the sodium-potassium-2 chloride cotransporter 1 (NKCC1) blocker bumetanide. These observations establish that glucose not only stimulates active Na absorption, a well-established phenomenon, but also induces a Ca-activated chloride secretion. This may explain the failure of glucose-based ORS to markedly reduce stool output in acute diarrhea. These results have immediate potential to improve the treatment outcomes for acute and/or chronic diarrheal diseases by replacing glucose with compounds that do not stimulate chloride secretion.

  4. [Estrogen replacement].

    Science.gov (United States)

    Søgaard, A J; Berntsen, G K; Magnus, J H; Tollan, A

    1998-02-10

    Recent research on long-term postmenopausal hormone replacement therapy (HRT) indicates a positive effect on both total mortality and morbidity. This has raised the question of widespread preventive long-term use of HRT. Possible side-effects and ideological issues related to preventive HRT have led to debate and uncertainty among health professionals, in the media, and in the population at large. In order to evaluate the level of knowledge about and attitudes towards HRT, a randomly selected group of 737 Norwegian women aged 16-79 was interviewed by the Central Bureau of Statistics. One in three women had received information about HRT in the last two years, mainly through weekly magazines and physicians. The proportion who answered the questions on knowledge correctly varied from 36% to 47%. Those who had been given information by a physician possessed accurate knowledge, had more positive attitudes towards HRT and were more willing to use HRT than women who had reviewed information through other channels. Women with a higher level of education were better informed and more knowledgeable than others, but were nevertheless more reluctant to use HRT than those who were less educated. The limited number of women who actually receive information on HRT, the low level of knowledge and the ambivalent attitudes toward HRT are a major challenge to the public health service.

  5. Comparison of the effects of nitric oxide and hydrogen sulfide on calcium and potassium currents of rat colonic smooth muscle%一氧化氮和硫化氢对大鼠结肠平滑肌钙钾电流影响的比较

    Institute of Scientific and Technical Information of China (English)

    全晓静; 罗和生; 陈炜; 崔凝; 夏虹; 余光

    2015-01-01

    目的 比较一氧化氮(NO)与硫化氢(H2S)对大鼠结肠平滑肌细胞钙钾电流的影响,并探讨其抑制结肠动力的机制.方法 采用酶消化法分离近端结肠平滑肌细胞,运用全细胞膜片钳技术记录NO供体硝普钠(SNP,200 μmol/L)和H2S供体硫氢化钠(NaHS,300 μmol/L)对平滑肌细胞L型钙通道电流(ICa.L)和大电导钙激活钾电流(IBKCa)的影响.结果 膜电位0 mV处,SNP和NaHS均显著抑制ICaL峰值,SNP使峰电流密度由[(-3.76±0.66)pA/pF]降低至[(-2.67±0.42)pA/pF](P<0.01);NaHS使峰电流密度由[(-4.13 ±0.29)pA/pF]降低至[(-2.73 ±0.76)pA/pF](P<0.01);SNP明显抑制L型钙通道Ⅰ~Ⅴ曲线,但不影响其电压依赖特性;而NaHS使L型钙通道Ⅰ~Ⅴ曲线右移;SNP不影响L型钙通道的激活和失活特性;NaHS使L型钙通道的激活曲线和失活曲线均显著右移(P<0.05);SNP促进IBKCa,使电流密度由[(12.7±1.9) pA/pF]增加至[(14.7±2.1) pA/pF](P<0.05);NaHS抑制IBKCa,电流密度由[(15.5 ±2.4) pA/pF]降低至[(12.4±2.9) pA/pF] (P <0.05).结论 NO和H2S均抑制大鼠结肠平滑肌细胞(SMCs)收缩,但两者作用机制不同,NO通过抑制L型钙通道,激活BKCa通道抑制平滑肌收缩,而H2S则通过抑制L型钙通道抑制平滑肌收缩,但同时也抑制BKCa通道,其可能参与平滑肌钙稳态的调节.%Objective To investigate and compare the effects of nitric oxide (NO) and hydrogen sulfide (H2S) on calcium and potassium currents of rat colonic smooth muscle cells (SMCs).Methods The whole-cell patch-clamp technique was used to record the currents of L-type calcium channels and large conductance Ca2+-activated K + (BKCa) channels in SMCs isolated from male Wistar rat.Results Both the NO donor Sodium nitroferricyanide (Ⅲ) dihydrate (SNP, 200 μmol/L) and the H2S donor NaHS(300 μmol/L) inhibited L-type calcium current (ICa, L) at membrane potential of 0 mV, after application of SNP and NaHS, the current density significantly reduced from

  6. [Diet low in potassium].

    Science.gov (United States)

    Sáez Rodríguez, Loreto; Meizoso Ameneiro, Ana; Pérez Paz, Ma Jesús; Valiño Pazos, Cristina

    2011-11-01

    After confirming the high prevalence rates in our hemodialysis unit of the following nursing diagnoses: nutritional imbalances--both excesses and shortages, willingness to improve nutrition and fear related to the consequences of excessive intake of potassium and manifested by the inhibition in some people towards the enjoyment of food, we decided to plan an educational strategy which later resulted in a nursing intervention for these diagnoses, with the objective of providing adequate resources for the monitoring of balanced diets with a restriction of potassium. Inspired by dietary rations, as well as recognized dietary programs of learning by points, we decided to incorporate these ideas to design an educational tool to facilitate advice to our patients on how to follow diet plans as well as the choice of appropriate foods. The result was a set of cards incorporating nutritional information of various kinds, aimed at our patients covering different aspects of the diet appropriate food rations using household measurements, promoting good food preparation, appropriate dietary advice for different chronic diseases and a scoring system of foods according to their potassium content. Together they form a board game available during the hemodialysis sessions that also takes into consideration other issues of importance related to conditions such as cognitive stimulation, coping with the disease, improving the therapeutic performance or resources to increase patient motivation. Although initially it was only an educational exercise, the result has turned out to be both enjoyable and entertaining.

  7. Doses de potássio e cálcio no crescimento da planta, na produção e na qualidade de frutas do morangueiro em cultivo sem solo Potassium and calcium doses on plant growth, fruit yield and quality of strawberries in soilless cultivation

    Directory of Open Access Journals (Sweden)

    Jerônimo Luiz Andriolo

    2010-02-01

    Full Text Available Com o objetivo de avaliar o efeito de doses de potássio fornecido pela fertirrigação e de cálcio na parte aérea sobre o crescimento da planta, a produção e a qualidade de frutas do morangueiro em cultivo sem solo, plantas de morangueiro foram cultivadas com solução nutritiva contendo 9 (T1, 6 (T2, testemunha e 4,28mmol L-1 (T3 de K+ e com a solução testemunha (T2 suplementada uma vez por semana por pulverizações foliares de cálcio nas concentrações de 2,5 (T4 e 5g L-1 de CaCl2 (T5. O crescimento da planta foi reduzido no tratamento com a concentração de potássio mais elevada (T1, e o maior IAF foi obtido na dose mais elevada de CaCl2 (T5. A maior produção de frutas foi obtida em T2 e T3, a acidez (AT foi maior em T1, enquanto o teor de sólidos solúveis (SST e a relação SST/AT não diferiram significativamente entre os tratamentos. Concluiu-se que o aumento da concentração de potássio na solução nutritiva diminui o crescimento, a produção e a qualidade das frutas de morango e que a aplicação de cálcio na parte aérea das plantas por meio do CaCl2 reduz a produção de frutas.In order to evaluate the effect of potassium doses supplied by fertigation and of calcium by foliar spray on plant growth, fruit yield and quality of soilless grown strawberries, plants were supplied with nutrient solutions at K+ concentrations of 9 (T1; 6 (T2, control and 4.28mmol L-1 (T3 and with the control nutrient solution (T2 supplemented once a week by spraying CaCl2 on shoot at concentrations of 2.5 (T4 and 5g L- 1 (T5. Plant growth was lower in the higher potassium concentration (T1 and the highest LAI was recorded in the higher CaCl2 dose (T5. Fruit yield was higher in T2 and T3, the titratable acidity (TA was higher in T1, while total soluble solids (TSS and the ratio TTS/TA did not differ among treatments. It was concluded that high potasium concentration in the nutrient solution reduces plant growth, fruit yield and quality and

  8. Potassium Channelopathies and Gastrointestinal Ulceration

    Science.gov (United States)

    Han, Jaeyong; Lee, Seung Hun; Giebisch, Gerhard; Wang, Tong

    2016-01-01

    Potassium channels and transporters maintain potassium homeostasis and play significant roles in several different biological actions via potassium ion regulation. In previous decades, the key revelations that potassium channels and transporters are involved in the production of gastric acid and the regulation of secretion in the stomach have been recognized. Drugs used to treat peptic ulceration are often potassium transporter inhibitors. It has also been reported that potassium channels are involved in ulcerative colitis. Direct toxicity to the intestines from nonsteroidal anti-inflammatory drugs has been associated with altered potassium channel activities. Several reports have indicated that the long-term use of the antianginal drug Nicorandil, an adenosine triphosphate-sensitive potassium channel opener, increases the chances of ulceration and perforation from the oral to anal regions throughout the gastrointestinal (GI) tract. Several of these drug features provide further insights into the role of potassium channels in the occurrence of ulceration in the GI tract. The purpose of this review is to investigate whether potassium channelopathies are involved in the mechanisms responsible for ulceration that occurs throughout the GI tract. PMID:27784845

  9. Potassium Channelopathies and Gastrointestinal Ulceration.

    Science.gov (United States)

    Han, Jaeyong; Lee, Seung Hun; Giebisch, Gerhard; Wang, Tong

    2016-11-15

    Potassium channels and transporters maintain potassium homeostasis and play significant roles in several different biological actions via potassium ion regulation. In previous decades, the key revelations that potassium channels and transporters are involved in the production of gastric acid and the regulation of secretion in the stomach have been recognized. Drugs used to treat peptic ulceration are often potassium transporter inhibitors. It has also been reported that potassium channels are involved in ulcerative colitis. Direct toxicity to the intestines from nonsteroidal anti-inflammatory drugs has been associated with altered potassium channel activities. Several reports have indicated that the long-term use of the antianginal drug Nicorandil, an adenosine triphosphate-sensitive potassium channel opener, increases the chances of ulceration and perforation from the oral to anal regions throughout the gastrointestinal (GI) tract. Several of these drug features provide further insights into the role of potassium channels in the occurrence of ulceration in the GI tract. The purpose of this review is to investigate whether potassium channelopathies are involved in the mechanisms responsible for ulceration that occurs throughout the GI tract.

  10. Pulmonary artery perfusion with cold modified Low- Potassium Dextran solution reduces lung injury in combined aortic and mitral valve replacement%双瓣置换术中肺动脉灌注低温改良LPD液的肺保护作用

    Institute of Scientific and Technical Information of China (English)

    马明星; 刘立明; 张伟; 廖晓波; 易定武; 彭清云

    2009-01-01

    目的 探讨双瓣置换术中,肺动脉灌注低温改良LPD液对肺损伤的保护作用.方法 24例需实施双瓣置换术的风心病患者,对照组14例和灌注组10例,灌注组常规完成手术+肺动脉灌注低温改良LPD液,对照组常规完成手术,未行肺动脉灌注.术前、停CPB时、停CPB后1、2、6、12 h六个时间点监测两组病例的氧合指数,术前、停CPB时、停CPB后6、12 h四个时间点检测血浆IL-6、IL-10的水平.结果 与对照组相比,灌注组术后氧合指数明显改善,IL-6表达降低,IL-10表达增加.结论 CPB中肺动脉灌注低温改良LPD液能减轻双瓣置换术后肺损伤,改善肺功能.%Objective This study was to evaluate the protective effect of pulmonary perfusion with cold modified low- potassium dextran (LPD) solution on lung function after cardiopulmonary bypass in combined aortic and mitral valve replacement. Method Twenty-four consecutive adult patients with combined aortic and mitral valve disease were divided into a control group ( n =14) and a perfused group ( n = 10). Cold modified LPD solution was infused to the main pulmonary artery in the protective group. PaO_2/FiO_2 were monitored at six different time points; preoperation, 0 hour, 1 hours, 2 hours, 6 hours and 12 hours after the termination of CPB. Concentrations of interleukin-6 and interleukin-10 in plasma were measured at four different time points; preoperation, 0 hour, 6 hours, and 12 hours after the termination of CPB. Result PaO_2/FiO_2 in the perfused group were increased more than that in the control group. The IL-6 and IL-10 increased in both groups after operations( P <0. 05). Patients of the perfused group showed significantly reduced IL-6 expression, compared with the control group ( P <0. 001), but the rising extents of IL-10 in the perfused group were higher than that in the control group ( P <0.001). Conclusion Pulmonary artery perfusion with cold modified LPD solution during cardiopulmonary bypass

  11. Nonequilibrium calcium dynamics regulate the autonomous firing pattern of rat striatal cholinergic interneurons.

    Science.gov (United States)

    Goldberg, Joshua A; Teagarden, Mark A; Foehring, Robert C; Wilson, Charles J

    2009-07-01

    Striatal cholinergic interneurons discharge rhythmically in two patterns associated with different afterhyperpolarization timescales, each dictated by a different calcium-dependent potassium current. Single spiking depends on a medium-duration afterhyperpolarization (mAHP) generated by rapid SK currents that are associated with N-type calcium channels. Periodic bursting is driven by a delayed and slowly decaying afterhyperpolarization (sAHP) current associated with L-type channels. Using calcium imaging we show that the calcium transients underlying these currents exhibit two corresponding timescales throughout the somatodendritic tree. This result is not consistent with spatial compartmentalization of calcium entering through the two calcium channels and acting on the two potassium currents, or with differences in channel gating kinetics of the calcium dependent potassium currents. Instead, we show that nonequilibrium dynamics of calcium redistribution among cytoplasmic binding sites with different calcium binding kinetics can give rise to multiple timescales within the same cytoplasmic volume. The resulting independence of mAHP and sAHP currents allows cytoplasmic calcium to control two different and incompatible firing patterns (single spiking or bursting and pausing), depending on whether calcium influx is pulsatile or sustained. During irregular firing, calcium entry at both timescales can be detected, suggesting that an interaction between the medium and slow calcium-dependent afterhyperpolarizations may underlie this firing pattern.

  12. Potassium dependent rescue of a myopathy with core-like structures in mouse.

    Science.gov (United States)

    Hanson, M Gartz; Wilde, Jonathan J; Moreno, Rosa L; Minic, Angela D; Niswander, Lee

    2015-01-07

    Myopathies decrease muscle functionality. Mutations in ryanodine receptor 1 (RyR1) are often associated with myopathies with microscopic core-like structures in the muscle fiber. In this study, we identify a mouse RyR1 model in which heterozygous animals display clinical and pathological hallmarks of myopathy with core-like structures. The RyR1 mutation decreases sensitivity to activated calcium release and myoplasmic calcium levels, subsequently affecting mitochondrial calcium and ATP production. Mutant muscle shows a persistent potassium leak and disrupted expression of regulators of potassium homeostasis. Inhibition of KATP channels or increasing interstitial potassium by diet or FDA-approved drugs can reverse the muscle weakness, fatigue-like physiology and pathology. We identify regulators of potassium homeostasis as biomarkers of disease that may reveal therapeutic targets in human patients with myopathy of central core disease (CCD). Altogether, our results suggest that amelioration of potassium leaks through potassium homeostasis mechanisms may minimize muscle damage of myopathies due to certain RyR1 mutations.

  13. Fabrication and biocompatibility in vitro of potassium titanate biological thin film/titanium alloy biological composite

    Institute of Scientific and Technical Information of China (English)

    QI Yumin; HE Yun; CUI Chunxiang; LIU Shuangjin; WANG Huifen

    2007-01-01

    A potassium titanate biological thin film/titanium alloy biological composite was fabricated by way of bionic chemistry.The biocompatibility fn vitro of Ti-15Mo-3Nb and the potassium titanate biological thin film/titanium alloy was studied using simulated body fluid cultivation,kinetic clotting of blood and osteoblast cell cultivation experiments in vitro.By comparing the biological properties of both materials,the following conclusions can be obtained:(1)The deposition of a calcium phosphate layer was not found on the surface of Ti-15Mo-3Nb,so it was bioinert.Because the network of potassium titanate biological thin film could induce the deposition of a calcium phosphate layer,this showed that it had excellent bioactivity.(2)According to the values of kinetic clotting,the blood coagulation time of the potassium titanate biological thin film was more than that of Ti-15Mo-3Nb.It was obvious that the potassium titanate biological thin film possessed good hemocompatibility.(3)The cell compatibility of both materials was very good.However,the growth trend and multiplication of osteoblast cells on the surface of potassium titanate biological thin film was better,which made for the concrescence of wounds during the earlier period.As a result,the potassium titanate biological thin film/titanium alloy showed better biocompatibility and bioactivity.

  14. Calcium in diet

    Science.gov (United States)

    ... D is needed to help your body use calcium. Milk is fortified with vitamin D for this reason. ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ...

  15. 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)

  16. Potassium oxalurate monohydrate

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available The title salt, poly[aqua-μ3-oxalurato-potassium(I], [K(C3H3N2O4(H2O]n, which was obtained from a water solution of oxaluric acid and KOH at room temperature, crystallizes as potassium and oxalurate ions along with a water molecule. The K+ cation lies on a crystallographic twofold rotation axis (site symmetry 2, Wyckoff position f, and the water and oxalurate molecules are located within different mirror planes (site symmetry m, Wyckoff position g. The K+ cation is eight-coordinated by six O atoms of six oxalurate ligands and two O atoms from two water molecules in a distorted square-antiprismatic geometry. All of the eight coordinated O atoms are in a monodentate bridging mode, with alternate bridged K...K distances of 3.5575 (12 and 3.3738 (12 Å. The oxalurate ligand shows a μ3-bridging coordination mode, which links the K+ cation into a three-dimensional network. The oxalurate ligands and the water molecules are involved in inter- and intramolecular N—H...O, and O—H...O hydrogen bonds, which stabilize the network.

  17. Calcium supplements

    Science.gov (United States)

    ... Related Bone Diseases National Resource Center. Calcium and vitamin D: Important at every age. NIAMS.NIH.gov website. www.niams.nih.gov/Health_Info/Bone/Bone_Health/Nutrition . Updated May 2015. Accessed March ...

  18. 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

  19. Optogenetic techniques for the study of native potassium channels

    Directory of Open Access Journals (Sweden)

    Guillaume Eric Sandoz

    2013-04-01

    Full Text Available Optogenetic tools were originally designed to target specific neurons for remote control of their activity by light and have largely been built around opsin-based channels and pumps. These naturally photosensitive opsins are microbial in origin and are unable to mimic the properties of native neuronal receptors and channels. Over the last 8 years, photoswitchable-tethered ligands (PTLs have enabled fast and reversible control of mammalian ion channels, allowing optical control of neuronal activity. One such PTL, MAQ, contains a maleimide (M to tether the molecule to a genetically engineered cysteine, a photoisomerizable azobenzene (A linker and a pore-blocking quaternary ammonium group (Q. MAQ was originally used to photo-control SPARK, an engineered light-gated potassium channel derived from Shaker. Potassium channel photo-block by MAQ has recently been extended to a diverse set of mammalian potassium channels including channels in the voltage-gated and K2P families. Photoswitchable potassium channels, which maintain native properties, pave the way for the optical control of specific aspects of neuronal function and for high precision probing of a specific channel’s physiological functions. To extend optical control to natively expressed channels, without overexpression, one possibility is to develop a knock-in mouse in which the wild type channel gene is replaced by its light-gated version. Alternatively, the recently developed photoswitchable-conditional-subunit technique (PCS provides photocontrol of the channel of interest by molecular replacement of wild type complexes. Finally, photochromic ligands (PCLs also allow photocontrol of potassium channels without genetic manipulation using soluble compounds. In this review we discuss different techniques for optical control of native potassium channels and their associated advantages and disadvantages.

  20. Optogenetic techniques for the study of native potassium channels.

    Science.gov (United States)

    Sandoz, Guillaume; Levitz, Joshua

    2013-01-01

    Optogenetic tools were originally designed to target specific neurons for remote control of their activity by light and have largely been built around opsin-based channels and pumps. These naturally photosensitive opsins are microbial in origin and are unable to mimic the properties of native neuronal receptors and channels. Over the last 8 years, photoswitchable tethered ligands (PTLs) have enabled fast and reversible control of mammalian ion channels, allowing optical control of neuronal activity. One such PTL, maleimide-azobenzene-quaternary ammonium (MAQ), contains a maleimide (M) to tether the molecule to a genetically engineered cysteine, a photoisomerizable azobenzene (A) linker and a pore-blocking quaternary ammonium group (Q). MAQ was originally used to photocontrol SPARK, an engineered light-gated potassium channel derived from Shaker. Potassium channel photoblock by MAQ has recently been extended to a diverse set of mammalian potassium channels including channels in the voltage-gated and K2P families. Photoswitchable potassium channels, which maintain native properties, pave the way for the optical control of specific aspects of neuronal function and for high precision probing of a specific channel's physiological functions. To extend optical control to natively expressed channels, without overexpression, one possibility is to develop a knock-in mouse in which the wild-type channel gene is replaced by its light-gated version. Alternatively, the recently developed photoswitchable conditional subunit technique provides photocontrol of the channel of interest by molecular replacement of wild-type complexes. Finally, photochromic ligands also allow photocontrol of potassium channels without genetic manipulation using soluble compounds. In this review we discuss different techniques for optical control of native potassium channels and their associated advantages and disadvantages.

  1. Neural synchronization via potassium signaling

    DEFF Research Database (Denmark)

    Postnov, Dmitry E; Ryazanova, Ludmila S; Mosekilde, Erik

    2006-01-01

    Using a relatively simple model we examine how variations of the extracellular potassium concentration can give rise to synchronization of two nearby pacemaker cells. With the volume of the extracellular space and the rate of potassium diffusion as control parameters, the dual nature of this reso...

  2. Potassium supplementation and heart rate

    NARCIS (Netherlands)

    Gijsbers, L.; Molenberg, Famke; Bakker, S.J.L.; Geleijnse, J.M.

    2016-01-01

    Background and aims: Increasing the intake of potassium has been shown to lower blood pressure, but whether it also affects heart rate (HR) is largely unknown. We therefore assessed the effect of potassium supplementation on HR in a meta-analysis of randomized controlled trials. Methods and resul

  3. 流加补氨水代替碳酸钙在赤霉素GA4+7生物发酵中的研究%Study of Replacing Calcium Carbonate with Ammonium Feeding in Gibberellins A4+7 Fermentation

    Institute of Scientific and Technical Information of China (English)

    张文宣; 刘义雄; 周圣骄; 谷田; 钟名兴

    2011-01-01

    Effects of replacing calcium carbonate with ammonium feeding in gibberellins GA4+7 fermentation and recovered rate were studied. The research showed that the continuous ammonium feeding technique could be utilized in gibberellins GA4+7 fermentation and production, and could positively enhance the production of gibberellins GA4+7. The yield/titer was 6% higher than control and recovered rate was 4% higher because the negative effect of calcium on nltrafiltration membrane (NF) and nanofiltration membrane (NF) was eliminated.%研究了在赤霉素GA4+7生物发酵过程中,流加补氨水代替碳酸钙精确调控发酵pH对发酵与提炼的影响,结果表明流加补氨水代替碳酸钙工艺可应用于赤霉素GA4+7发酵生产中,对赤霉素GA4+7发酵具有促进作用。其能提高发酵水平6%以上,同时因消除了钙离子对膜分离的影响,可提高后提取工艺收率4%以上。

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    of extracellular calcium, plasma membrane depolarization by high extracellular potassium, and the L-type voltage-operated calcium channel inhibitor, nifedipine. In contrast, all these treatments enhanced the spread of P2 receptor-mediated ICW in UMR rat osteoblastic cells. Using UMR cells transfected to express Cx......43 (UMR/Cx43) we confirmed that nifedipine sensitivity of ICW required Cx43 expression. In human osteoblastic cells, gap junction-dependent ICW also required activation of L-type calcium channels and influx of extracellular calcium....

  5. Bioceramics of calcium orthophosphates.

    Science.gov (United States)

    Dorozhkin, Sergey V

    2010-03-01

    A strong interest in use of ceramics for biomedical applications appeared in the late 1960's. Used initially as alternatives to metals in order to increase a biocompatibility of implants, bioceramics have become a diverse class of biomaterials, presently including three basic types: relatively bioinert ceramics, bioactive (or surface reactive) and bioresorbable ones. Furthermore, any type of bioceramics could be porous to provide tissue ingrowth. This review is devoted to bioceramics prepared from calcium orthophosphates, which belong to the categories of bioresorbable and bioactive compounds. During the past 30-40 years, there have been a number of major advances in this field. Namely, after the initial work on development of bioceramics that was tolerated in the physiological environment, emphasis was shifted towards the use of bioceramics that interacted with bones by forming a direct chemical bond. By the structural and compositional control, it became possible to choose whether the bioceramics of calcium orthophosphates was biologically stable once incorporated within the skeletal structure or whether it was resorbed over time. At the turn of the millennium, a new concept of calcium orthophosphate bioceramics, which is able to regenerate bone tissues, has been developed. Current biomedical applications of calcium orthophosphate bioceramics include replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery. Potential future applications of calcium orthophosphate bioceramics will include drug-delivery systems, as well as they will become effective carriers of growth factors, bioactive peptides and/or various types of cells for tissue engineering purposes.

  6. Cardiac potassium channel subtypes

    DEFF Research Database (Denmark)

    Schmitt, Nicole; Grunnet, Morten; Olesen, Søren-Peter

    2014-01-01

    that they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K(+) channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure......About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K(+) channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K(+) channels...... drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate...

  7. Therapy of hypoparathyroidism by replacement with parathyroid hormone

    DEFF Research Database (Denmark)

    Rejnmark, Lars; Underbjerg, Line; Sikjaer, Tanja

    2014-01-01

    Hypoparathyroidism (HypoPT) is a state of hypocalcemia due to inappropriate low levels of parathyroid hormone (PTH). HypoPT is normally treated by calcium supplements and activated vitamin D analogues. Although plasma calcium is normalized in response to conventional therapy, quality of life (Qo......L) seems impaired and patients are at increased risk of renal complications. A number of studies have suggested subcutaneous injections with PTH as an alternative therapy. By replacement with the missing hormone, urinary calcium may be lowered and QoL may improve. PTH replacement therapy (PTH-RT) possesses...

  8. Consumo de fibra dietética, sodio, potasio y calcio y su relación con la presión arterial en hombres adultos normotensos Dietary fiber, energy, sodium, potassium and calcium intake and its relationship to blood pressure in normotensive male adults

    Directory of Open Access Journals (Sweden)

    Martha Nydia Ballesteros-Vásquez

    1998-05-01

    Full Text Available Objetivo. Evaluar el efecto del consumo de fibra dietética, energía, sodio, potasio y calcio sobre la presión arterial de un grupo de adultos normotensos, tomando en cuenta indicadores tales como la edad, el sexo, la actividad física y la obesidad. Material y métodos. Se evaluaron 38 sujetos del sexo masculino de 30 a 45 años de edad, normotensos, aparentemente sanos y residentes de la ciudad de Hermosillo, Sonora, México. Se midió la presión arterial y se realizó una evaluación dietética, antropométrica y de actividad física. Resultados. La dieta resultó ser alta en fibra y en grasa. El sodio estaba 56% por arriba de la recomendación en 87% de los casos y fue la variable que más efecto mostró sobre la presión diastólica. De los sujetos estudiados, 36.9% tenían sobrepeso y obesidad, y se encontró una asociación significativa entre el índice de masa corporal y la presión diastólica y sistólica. Conclusiones. Existe una asociación significativa entre la hipertensión arterial y el alto consumo de sodio, el sobrepeso y la obesidad en sujetos normotensos.Objective. To evaluate the effect of dietary fiber, energy, sodium, calcium and potassium intake on the blood pressure of a group of normotensive adults. Material and methods. Subjects were 38 healthy normotensive adult males aged 30-45 years, resident of Hermosillo, Sonora, Mexico. Blood pressure, diet, anthropometric data and physical activity were recorded. Results. Their diet was high in fiber and fat. Sodium intake was 56% above the recommended values in 87% of the subjects, and the variable with the highest correlation to diastolic blood pressure. Of the subjects, 36.9% were overweight and obese, and a significant statistic association was found between BMI and diastolic and systolic blood pressure. Conclusions. A significant relationship was found between hypertension and high consumption of sodium, overweight and obesity in healthy adult normotensive males.

  9. Calcium-dependent potassium current in barnacle photoreceptor

    OpenAIRE

    1981-01-01

    When barnacle lateral eye photoreceptors are depolarized to membrane potentials of 0 to +50 mV in the dark, the plot of outward current through the cell membrane against time has two distinct maxima. The first maximum occurs 5-10 ms after the depolarization began. The current then decays to a minimum at approximately 500 ms after the onset of depolarization, and then increases to a second maximum 4-6 s after the depolarization began. If depolarization is maintained, the current again decays t...

  10. Determination and comparison of vitamin C, calcium and potassium ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-18

    Aug 18, 2008 ... It is evident that the growing interest in organically grown produce has ... from local supermarkets within Central Coast, New South Wales in Australia from late March ..... The authors would like to thank the Australian govern-.

  11. Inhibition of large conductance calcium-dependent potassium ...

    African Journals Online (AJOL)

    which Rho-kinase increases smooth muscle contraction. © Copyright 2014 African Association ... acetylcholine (10 mM) was obtained on each ring for assessment of .... been shown to mediate the actions of important vasodilators such as nitric.

  12. Sodium-potassium synergism in Theobroma cacao: stimulation of photosynthesis, water-use efficiency and mineral nutrition.

    Science.gov (United States)

    Gattward, James N; Almeida, Alex-Alan F; Souza, José O; Gomes, Fábio P; Kronzucker, Herbert J

    2012-11-01

    In ecological setting, sodium (Na(+)) can be beneficial or toxic, depending on plant species and the Na(+) level in the soil. While its effects are more frequently studied at high saline levels, Na(+) has also been shown to be of potential benefit to some species at lower levels of supply, especially in C4 species. Here, clonal plants of the major tropical C3 crop Theobroma cacao (cacao) were grown in soil where potassium (K(+)) was partially replaced (at six levels, up to 50% replacement) by Na(+), at two concentrations (2.5 and 4.0 mmol(c) dm(-3)). At both concentrations, net photosynthesis per unit leaf area (A) increased more than twofold with increasing substitution of K(+) by Na(+). Concomitantly, instantaneous (A/E) and intrinsic (A/g(s)) water-use efficiency (WUE) more than doubled. Stomatal conductance (g(s)) and transpiration rate (E) exhibited a decline at 2.5 mmol dm(-3), but remained unchanged at 4 mmol dm(-3). Leaf nitrogen content was not impacted by Na(+) supplementation, whereas sulfur (S), calcium (Ca(2+)), magnesium (Mg(2+)) and zinc (Zn(2+)) contents were maximized at 2.5 mmol dm(-3) and intermediate (30-40%) replacement levels. Leaf K(+) did not decline significantly. In contrast, leaf Na(+) content increased steadily. The resultant elevated Na(+)/K(+) ratios in tissue correlated with increased, not decreased, plant performance. The results show that Na(+) can partially replace K(+) in the nutrition of clonal cacao, with significant beneficial effects on photosynthesis, WUE and mineral nutrition in this major perennial C3 crop. Copyright © Physiologia Plantarum 2012.

  13. Localization and pharmacological characterization of voltage dependent calcium channels in cultured neocortical neurons

    DEFF Research Database (Denmark)

    Timmermann, D B; Lund, T M; Belhage, B

    2001-01-01

    using the fluorescent calcium chelator fura-2. The types of calcium channels present at the synaptic terminal were determined by the inhibitory action of calcium channel blockers on potassium-induced [3H]GABA release in the same cell preparation. L-, N-, P-, Q- and R-/T-type voltage dependent calcium...... channels were differentially distributed in somata, neurites and nerve terminals. omega-conotoxin MVIIC (omega-CgTx MVIIC) inhibited approximately 40% of the Ca(2+)-rise in both somata and neurites and 60% of the potassium induced [3H]GABA release, indicating that the Q-type channel is the quantitatively...... in cytosolic calcium concentration. The results of this investigation demonstrate that pharmacologically distinct types of voltage dependent calcium channels are differentially localized in cell bodies, neurites and nerve terminals of mouse cortical neurons but that the Q-type calcium channel appears...

  14. A new pH-sensitive rectifying potassium channel in mitochondria from the embryonic rat hippocampus.

    Science.gov (United States)

    Kajma, Anna; Szewczyk, Adam

    2012-10-01

    Patch-clamp single-channel studies on mitochondria isolated from embryonic rat hippocampus revealed the presence of two different potassium ion channels: a large-conductance (288±4pS) calcium-activated potassium channel and second potassium channel with outwardly rectifying activity under symmetric conditions (150/150mM KCl). At positive voltages, this channel displayed a conductance of 67.84pS and a strong voltage dependence at holding potentials from -80mV to +80mV. The open probability was higher at positive than at negative voltages. Patch-clamp studies at the mitoplast-attached mode showed that the channel was not sensitive to activators and inhibitors of mitochondrial potassium channels but was regulated by pH. Moreover, we demonstrated that the channel activity was not affected by the application of lidocaine, an inhibitor of two-pore domain potassium channels, or by tertiapin, an inhibitor of inwardly rectifying potassium channels. In summary, based on the single-channel recordings, we characterised for the first time mitochondrial pH-sensitive ion channel that is selective for cations, permeable to potassium ions, displays voltage sensitivity and does not correspond to any previously described potassium ion channels in the inner mitochondrial membrane. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).

  15. Electron imaging of calcium oxalate crystals in beagle dogs’ urine

    Directory of Open Access Journals (Sweden)

    Walaa I. Mohamaden

    2014-06-01

    Full Text Available Calcium oxalate crystalluria appears to be a common problem in most of small animal clinics. This current study aimed at inducing a condition of oxalate crystalluria in beagles and record the primary changes in canine blood and urine on response to oxalates injection. 15 dogs were divided into two groups; those in the treatment group were injected intravenously with 0.5 M potassium oxalate and the dogs of control group were injected with physiological saline for five successive days. Urine test revealed a significant decrease in urinary creatinine and urinary urea nitrogen levels. The ultrastructural examination of urine sediment showed typical and atypical phases of calcium oxalate crystals and the X-ray defractionation of these crystals showed high content of calcium in addition to other minerals. Therefore potassium oxalate injection may provide an example of calcium oxalate crystalluria which may answer some question around the pathogenesis of this problem in dogs.

  16. Transformation of modified brushite to hydroxyapatite in aqueous solution: effects of potassium substitution.

    Science.gov (United States)

    Kumar, M; Xie, J; Chittur, K; Riley, C

    1999-08-01

    Brushite (dicalcium phosphate dihydrate, DCPD, CaHPO4 x 2H2O) was deposited electrolytically from calcium dihydrogen phosphate solution with and without potassium chloride (KCl) as a supporting electrolyte. The kinetics of brushite transformation to hydroxyapatite (HA, Ca5(PO4)3OH) in the presence of calcium and protein free, aqueous body fluid (Hank's balanced salt solution, HBSS) was investigated. We present evidence that the deposition of brushite in a KCl-supported electrochemical bath yields a modified brushite where some of the calcium is substituted by potassium. Transformation of both normal (i.e. potassium free) and modified brushite to hydroxyapatite upon exposure to calcium and protein-free aqueous fluid (HBSS) was followed by reflectance Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. Changes in the morphology of the coatings were studied using scanning electron microscopy (SEM). Results indicate that modified brushite undergoes faster transformation to hydroxyapatite in HBSS in comparison to normal brushite. Our results show that the presence of potassium ions in the brushite not only favors the formation of different intermediate phases but also alters transformation rates to HA.

  17. Presynaptic calcium signalling in cerebellar mossy fibres

    Directory of Open Access Journals (Sweden)

    Louiza B Thomsen

    2010-02-01

    Full Text Available 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 TTX-sensitive fast Na+ spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers. Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none tetrodotoxin (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 one second affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be modulated locally, suggesting that cerebellar glomeruli may be dynamically sub-compartmentalized due to ongoing inhibition mediated by Golgi cells. This could provide a fine-grained control of mossy fibre-granule cell information transfer and synaptic plasticity within a mossy fibre rosette.

  18. The sarcoplasmic calcium pump - a most efficient ion translocating system.

    Science.gov (United States)

    Hasselbach, W

    1977-04-21

    In contrast to the sodium-potassium transporting plasma membranes, the sarcoplasmic membranes (SR) are highly specialized structures into which only two major intrinsic proteins, a calcium transporting protein and a calcium binding protein are embedded. The calcium transporting protein is a highly asymmetric molecule. It binds two calcium ions with a very high affinity at its external, and two calcium ions with low affinity at the internal section of the molecule. ATP is bound with high afffinity to an external binding site, inducing a conformational change. When the vesicular membranes are exposed to solutions containing Ca++, Mg++ and ATP, ATP is hydrolyzed and simultaneously calcium ions are translocated from the external medium into the vesicular space. When calcium ions are translocated in the opposite direction, ATP is synthesized. The calcium-ATP ratio for ATP cleavage as well as for ATP synthesis is 2. Thus, the SR membranes can transform reversibly chemical into osmotical energy. Inward and outward movements of calcium ions are relatively slow processes connected with the appearance and disappearance of different phosphorylated intermediates. One phosphorylated intermediate is formed by phosphoryltransfer from ATP when calcium ions are present in the medium. In contrast, when calcium ions are absent from the external medium, two different intermediates can be formed by the incorporation of inorganic phosphate. Only when calcium ions present in the internal space of the vesicles are released, the incorporation of inorganic phosphate gives rise to an intermediate who phosphoryl group can be transferred to ADP.

  19. Calcium Orthophosphate Cements and Concretes

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2009-03-01

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

  20. Bonding over Dentin Replacement Materials.

    Science.gov (United States)

    Meraji, Naghmeh; Camilleri, Josette

    2017-08-01

    Dentin replacement materials are necessary in large cavities to protect the pulp and reduce the bulk of filling material. These materials are layered with a composite resin restorative material. Microleakage caused by poor bonding of composite resin to underlying dentin replacement material will result in pulp damage. The aim of this study was to characterize the interface between dentin replacement materials and composite resin and to measure the shear bond strength after dynamic aging. Biodentine (Septodont, Saint Maur-des-Fosses, France), Theracal LC (Bisco, Schaumburg, IL), and Fuji IX (GC, Tokyo, Japan) were used as dentin replacement materials. They were then overlaid with a total-etch and bonding agent or a self-etch primer and composite resin or a glass ionomer cement. All combinations were thermocycled for 3000 cycles. The interface was characterized using scanning electron microscopy and elemental mapping. Furthermore, the shear bond strength was assessed. The Biodentine surface was modified by etching. The Theracal LC and Fuji IX microstructure was unchanged upon the application of acid etch. The Biodentine and glass ionomer interface showed an evident wide open space, and glass particles from the glass ionomer adhered to the Biodentine surface. Elemental migration was shown with aluminum, barium, fluorine, and ytterbium present in Biodentine from the overlying composite resin. Calcium was more stable. The bond strength between Theracal LC and composite using a total-etch technique followed by self-etch primer achieved the best bond strength values. Biodentine exhibited the weakest bond with complete failure of bonding shown after demolding and thermocycling. Dynamic aging is necessary to have clinically valid data. Bonding composite resin to water-based dentin replacement materials is still challenging, and further alternatives for restoration of teeth using such materials need to be developed. Copyright © 2017 American Association of Endodontists

  1. 21 CFR 184.1635 - Potassium iodate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium iodate. 184.1635 Section 184.1635 Food... Specific Substances Affirmed as GRAS § 184.1635 Potassium iodate. (a) Potassium iodate (KIO3, CAS Reg. No. 7758-05-6) does not occur naturally but can be prepared by reacting iodine with potassium hydroxide....

  2. 21 CFR 172.375 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium iodide. 172.375 Section 172.375 Food and... Dietary and Nutritional Additives § 172.375 Potassium iodide. The food additive potassium iodide may be safely used in accordance with the following prescribed conditions: (a) Potassium iodide may be...

  3. 21 CFR 184.1634 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium iodide. 184.1634 Section 184.1634 Food... Specific Substances Affirmed as GRAS § 184.1634 Potassium iodide. (a) Potassium iodide (KI, CAS Reg. No. 7681-11-0) is the potassium salt of hydriodic acid. It occurs naturally in sea water and in...

  4. 21 CFR 184.1610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium alginate. 184.1610 Section 184.1610 Food... Specific Substances Affirmed as GRAS § 184.1610 Potassium alginate. (a) Potassium alginate (CAS Reg. No... algae. Potassium alginate is prepared by the neutralization of purified alginic acid with appropriate...

  5. Calcium and bones

    Science.gov (United States)

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

  6. Calcium Carbonate

    Science.gov (United States)

    ... doctor if you have or have ever had kidney disease or stomach conditions.tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking calcium carbonate, call your doctor.

  7. Calcium Test

    Science.gov (United States)

    ... if a person has symptoms of a parathyroid disorder , malabsorption , or an overactive thyroid. A total calcium level is often measured as part of a routine health screening. It is included in the comprehensive metabolic panel (CMP) and the basic metabolic panel (BMP) , ...

  8. Preeminent productivity of 1,3-propanediol by Clostridium butyricum JKT37 and the role of using calcium carbonate as pH neutraliser in glycerol fermentation.

    Science.gov (United States)

    Tee, Zhao Kang; Jahim, Jamaliah Md; Tan, Jian Ping; Kim, Byung Hong

    2017-06-01

    Calcium carbonate was evaluated as a replacement for the base during the fermentation of glycerol by a highly productive strain of 1,3-propanediol (PDO), viz., Clostridium butyricum JKT37. Due to its high specific growth rate (µmax=0.53h(-1)), 40g/L of glycerol was completely converted into 19.6g/L of PDO in merely 7h of batch fermentation, leaving only acetate and butyrate as the by-products. The accumulation of these volatile fatty acids was circumvented with the addition of calcium carbonate as the pH neutraliser before the fermentation was inoculated. An optimal amount of 15g/L of calcium carbonate was statistically determined from screening with various glycerol concentrations (20-120g/L). By substituting potassium hydroxide with calcium carbonate as the pH neutraliser for fermentation in a bioreactor, a similar yield (YPDO/glycerol=0.6mol/mol) with a constant pH was achieved at the end of the fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Calcination Reaction of Potassium Feldspar in CaSO4 and Its Decomposition Products%钾长石在CaSO4及其分解产物下的焙烧反应研究

    Institute of Scientific and Technical Information of China (English)

    夏举佩; 彭健; 李国斌; 苏毅; 阳超琴

    2014-01-01

    Roasting reaction process was proved under real system according to reductive decomposition of calcium sulfate product ingredients, feldspar itself by adding calcium sulfate and high temperature properties and decomposition reaction of calcined product. The results show that: In 1200℃, calcium sulfate and potassium feldspar can react to form eutecticK2Ca2(SO4)3, this material structural stability, no water-soluble characteristics. CaS does not react with K-feldspar, both independent present in the system. CaO have better reactivity on the replacement of the potassium feldspar. in the presence of calcium sulfate, calcium oxide is generated when there is insufifcientK2S2O8, when sufifcient calcium oxide generatedK2SO4. Silicon, calcium aluminate and systems of the material ratio and operating conditions.%根据硫酸钙还原分解产物成分,通过钾长石自身高温特性和添加硫酸钙及分解产物焙烧反应研究,探明实际体系下焙烧反应历程。研究结果表明:在1200℃下,硫酸钙能与钾长石进行反应,形成低共熔物K2Ca2(SO4)3,此物质结构稳定,无水溶特性;CaS不与钾长石反应,二者独立存在于体系中;CaO有较好反应活性,能置换出钾长石中的氧化钾;在有硫酸钙存在时,当氧化钙量不足时生成K2S2O8,当氧化钙充足时则生成K2SO4。硅、铝酸的钙盐则与体系物料配比及操作条件有关。

  10. Physical Properties of Acidic Calcium Phosphate Cements

    OpenAIRE

    2014-01-01

    The gold standard for bone replacement today, autologous bone, suffers from several disadvantages, such as the increased risk of infection due to the need for two surgeries. Degradable synthetic materials with properties similar to bone, such as calcium phosphate cements, are a promising alternative. Calcium phosphate cements are suited for a limited amount of applications and improving their physical properties could extend their use into areas previously not considered possible. For example...

  11. Calcium-dependent 86 Rb efflux and ethanol intoxication: studies of human red blood cells and rodent brain synaptosomes.

    Science.gov (United States)

    Yamamoto, H A; Harris, R A

    1983-04-08

    Effects of ethanol on calcium-dependent potassium efflux were investigated in red blood cells (RBC) from humans and brain synaptosomes from rats and mice. 86 Rb was used as a tracer for potassium. Synaptosomes and RBC were lysed and resealed with 86 Rb and calcium-EGTA buffers to regulate intracellular levels of ionized calcium. In vitro addition of ethanol (100 mM) stimulated the calcium-dependent 86 Rb efflux of synaptosomes. This stimulation was blocked by apamin, an inhibitor of the calcium-dependent potassium current of nerve cells. In addition, intracerebroventricular injection of apamin inhibited ethanol-induced narcosis in mice, providing behavioral evidence for the importance of calcium-stimulated potassium efflux in alcohol intoxication. In vitro addition of ethanol, propanol or butanol increased calcium-dependent 86 Rb efflux of human RBC at low concentrations of free calcium, but did not change the calcium-independent efflux of 86 Rb. These results suggest that the calcium-dependent 86 Rb efflux of nerve endings may have an important role in the pharmacological and toxicological effects of ethanol.

  12. Modulation of Tartrates with Various Counterions on the Phases of Calcium Oxalate in Gelatinous Systems

    Institute of Scientific and Technical Information of China (English)

    Jian Ming OUYANG; Xiang Ping LI

    2005-01-01

    Effect of various counterions of tartrate on the crystallization of calcium oxalate in gel system was investigated using scanning electron microscopy and X-ray diffraction. Various tartrates with hydrogen (H2tart), sodium (Na2tart), potassium (K2tart), ammonium ((NH4)2tart), and a mixture of sodium and potassium cations (NaKtart) were considered. For H2tart, Na2tart, and (NH4)2tart, calcium oxalate dihydrate (COD) was induced. However, for K2tart and NaKtart,calcium oxalate trihydrate (COT) was obtained.

  13. 原发性高血压大鼠阴茎海绵体组织中电导型钙激活性钾通道的表达%The expression and correlation of intermediate conductance calcium-activated potassium channels in cavernous tissue of spontaneously hypertensive rats

    Institute of Scientific and Technical Information of China (English)

    廖胜; 高飞; 葛余正; 周六化; 吴然; 贾瑞鹏

    2014-01-01

    Objective Intermediate conductance calcium-activated potassium channels (IKCa),one of the key material of the endothelium-derived hyperpolarizing factor (EDHF) passway.To detect the expression of IKCa and explore hypertension impact IKCa expression in cavernous tissue of spontaneously hypertensive rats.Methods Male spontaneously hypertensive rats (SHR) (n =20) and normotensive Wistar Kyoto rats (WKY,n =10) were studied,Systolic blood pressure (SBP) was measured by noninvasive blood pressure instrument and erectile function was tested by injecting with apomorphine (APO),the rats were divided into 3 groups,namely hypertensive with erectile dysfunction (HBP-ED)group (n =13),hypertensive (HBP) group (n =7) and control group (n =10).The expression of IKCa gene mRNA and protein was assessed by Western blotting and reverse transcription-polymerase chain reaction (RT-PCR).Results Versus the WKY group,SHR group showed a higher systolic blood pressure [(202.43 ±9.89)vs.(127.21 ± 3.48) mmHg (1 mmHg =0.133 k Pa),P < 0.01].The expressions of IKCa protein and mRNA were the highest in the control group and the lowest in HBP-ED group.Conclusion The erectile function of penis is impacted seriously by hypertension,which may be related to the decreased expression of IKCa in cavernous tissue of spontaneously hypertensive rats.%目的 检测内皮依赖性超级化因子(EDHF)通路关键性物质中电导型钙激活性钾通道(IKCa)在原发性高血压大鼠阴茎海绵体组织的表达,探讨高血压对大鼠阴茎海绵体中IKCa表达的影响.方法 健康雄性原发性高血压大鼠(SHR) 20只及同系正常(WKY)大鼠10只,无创血压仪测量大鼠尾部收缩压(SBP),颈部皮下注射阿扑吗啡(APO)检验大鼠阴茎勃起,将大鼠分为高血压勃起功能障碍组(HBP-ED)、高血压组(HBP)和对照组(Control).运用Western blot和逆转录-聚合酶链反应(RT-PCR)技术检验大鼠阴茎海绵体中IKCa蛋白和mRNA的表达.结果 SHR

  14. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

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

    1984-01-01

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

  15. Shoulder Joint Replacement

    Science.gov (United States)

    ... Shoulder Replacement Options Shoulder replacement surgery is highly technical. It should be performed by a surgical team ... area and will meet a doctor from the anesthesia department. You, your anesthesiologist, and your surgeon will ...

  16. Partial knee replacement - slideshow

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series—Normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  17. On the structure of amorphous calcium carbonate--a detailed study by solid-state NMR spectroscopy.

    Science.gov (United States)

    Nebel, Holger; Neumann, Markus; Mayer, Christian; Epple, Matthias

    2008-09-01

    The calcium carbonate phases calcite, aragonite, vaterite, monohydrocalcite (calcium carbonate monohydrate), and ikaite (calcium carbonate hexahydrate) were studied by solid-state NMR spectroscopy ( (1)H and (13)C). Further model compounds were sodium hydrogencarbonate, potassium hydrogencarbonate, and calcium hydroxide. With the help of these data, the structure of synthetically prepared additive-free amorphous calcium carbonate (ACC) was analyzed. ACC contains molecular water (as H 2O), a small amount of mobile hydroxide, and no hydrogencarbonate. This supports the concept of ACC as a transient precursor in the formation of calcium carbonate biominerals.

  18. Equatorial potassium currents in lenses.

    Science.gov (United States)

    Wind, B E; Walsh, S; Patterson, J W

    1988-02-01

    Earlier work with the vibrating probe demonstrated the existence of outward potassium currents at the equator and inward sodium currents at the optical poles of the lens. By adding microelectrodes to the system, it is possible to relate steady currents (J) to the potential difference (PD) measured with a microelectrode. By injecting an outward current (I), it is possible to determine resistances and also the PD at which the steady outward potassium current becomes zero (PDJ = 0). At this PD the concentration gradient for potassium efflux and the electrical gradient for potassium influx are balanced so that there is no net flow of potassium across the membranes associated with the production of J. The PDJ = 0 for 18 rat lenses was 86 mV and that for 12 frogs lenses was -95 mV. This agrees with the potassium equilibrium potential and provides strong evidence to support the view that the outward equatorial current, J, is a potassium current. With the injection of outward current, I, the PD becomes more negative, the outward equatorial current, J, decreases, and the inward current at the optical poles increases. This suggests that there are separate electrical loops for K+ and Na+ that are partially linked by the Na, K-pump. Using Ohm's law, it is possible to calculate the input resistance (R = delta PD/I), the resistance related to the production of J (RJ = delta PD/delta J), and the effect of the combined resistances (delta J/I). The driving force for J can be estimated (PDJ = 0-PD). The relationships among currents, voltages and resistance can be used to determine the characteristics of the membranes that are associated with the outward potassium current observed at the equator. The effects of graded deformation of the lens were determined. The effects were reversible. The sites of inward and outward currents were not altered. Following deformation, the equatorial current, J, increased, and the PD became less negative. The PDJ = 0 remains the same so the ratio of K

  19. Renal adaptation to a high potassium intake. The role of hydrogen ion.

    Science.gov (United States)

    Tannen, R L; Wedell, E; Moore, R

    1973-09-01

    The influence on urinary acidification of prolonged ingestion of a high potassium diet was explored in normal men and dogs. In men, the response to acute ingestion of ammonium chloride was assessed in a paired fashion after 5 days of ingesting a formula diet of normal or high potassium content; whereas in animals chronically ingesting a small amount of hydrochloric acid, the response to an increase in daily potassium intake was assessed. Urine pH was lower in the potassium-loaded state with both these models, and the effect persisted in the dog studies as long as a high potassium intake was continued. The decrease in urine pH could not be accounted for by changes in plasma acid-base status, net acid excretion, rate of urine flow, urine ionic strength, or fixed buffer excretion, i.e., phosphate, creatinine, or organic acids. Studies of men with administration of exogenous aldosterone and studies of adrenalectomized dogs with constant, maintenance steroid replacement indicated that the decrease in urine pH does not result from altered aldosterone secretion.In the human studies the largest decreases in urine pH were associated with a concomitant diminution in both ammonium and net acid excretion, suggesting a primary decrease of ammonia diffusion into the urine. These events during potassium loading, which are the mirror image of changes during potassium depletion, suggest that the relation between potassium, urine acidification, and ammonia metabolism may play an important role in the maintenance of hydrogen ion and possibly potassium homeostasis during alterations in potassium intake.

  20. Potassium inhibits dietary salt-induced transforming growth factor-beta production.

    Science.gov (United States)

    Ying, Wei-Zhong; Aaron, Kristal; Wang, Pei-Xuan; Sanders, Paul W

    2009-11-01

    Human and animal studies demonstrate an untoward effect of excess dietary NaCl (salt) intake on cardiovascular function and life span. The endothelium in particular augments the production of transforming growth factor (TGF)-beta, a fibrogenic growth factor, in response to excess dietary salt intake. This study explored the initiating mechanism that regulates salt-induced endothelial cell production of TGF-beta. Male Sprague-Dawley rats were given diets containing different amounts of NaCl and potassium for 4 days. A bioassay for TGF-beta demonstrated increased (35.2%) amounts of active TGF-beta in the medium of aortic ring segments from rats on the high-salt diet compared with rats maintained on a 0.3% NaCl diet. Inhibition of the large-conductance, calcium-activated potassium channel inhibited dietary salt-induced vascular production of TGF-beta but did not affect production of TGF-beta by ring segments from rats on the low-salt diet. Immunohistochemical and Western analyses demonstrated the alpha subunit of the calcium-activated potassium channel in endothelial cells. Increasing medium [K+] inhibited production of dietary salt-induced vascular production levels of total and active TGF-beta but did not alter TGF-beta production by aortic rings from rats on the 0.3% NaCl diet. Increasing dietary potassium content decreased urinary active TGF-beta in animals receiving the high-salt diet but did not change urinary active TGF-beta in animals receiving the low-salt diet. The findings demonstrated an interesting interaction between the dietary intake of potassium and excess NaCl and further showed the fundamental role of the endothelial calcium-activated potassium channel in the vascular response to excess salt intake.

  1. Níveis de cálcio e granulometrias do calcário para frangas de reposição no período de 3 a 12 semanas de idade Calcium levels and particle size of limestone for replacement pullets in the period from 3 to 12 weeks old

    Directory of Open Access Journals (Sweden)

    Adriano Geraldo

    2006-02-01

    Full Text Available Realizou-se um experimento com o objetivo de avaliar os efeitos dos níveis de cálcio e das granulometrias do calcário na ração sobre os desenvolvimentos corporal e morfométrico do trato digestório de frangas de reposição. Foram utilizadas 1.400 frangas de reposição da linhagem Lohmann LSL, em delineamento inteiramente casualizado, em esquema fatorial 5 x 2 (níveis de cálcio x granulometrias do calcário, com cinco repetições de 28 e 18 aves por parcela, respectivamente, nos períodos de 3 a 7 e de 8 a 12 semanas de idade. As dietas experimentais, à base de milho, farelo de soja e farelo de trigo (trigo somente na recria, foram formuladas para ser isoprotéicas, isocalóricas e isofosfóricas (fosfato monoamônio. Além da suplementação com minerais, vitaminas e fitase (500 FTU/kg, as dietas foram acrescidas de calcário em granulometrias fina (DGM=0,135 mm e grossa (DGM=0,899 mm para apresentar os níveis de 0,60; 0,75; 0,90; 1,05 e 1,20% de cálcio total na dieta. Avaliaram-se o desempenho no período de 3 a 12 semanas, a morfometria do trato digestório e os teores de cinzas e minerais na tíbia de aves de cada parcela. O consumo de ração aumentou de forma linear com a elevação dos níveis de cálcio. Não houve diferenças significativas no ganho de peso, na conversão alimentar, na porcentagem do trato digestório e no comprimento do metatarso. Maiores teores de cinzas foram obtidos em frangas que receberam o nível de 0,60% de Ca e maior comprimento do intestino delgado em aves recebendo a granulometria grossa. O nível de 0,60% de cálcio e o calcário na granulometria grossa (DGM=0,899 mm foram ideais para o melhor desenvolvimento esquelético, o menor consumo de ração e o maior comprimento do intestino delgado.The effects of feeding different calcium levels and limestone particle sizes on body and morphometric development of the digestive tract in replacement pullets were evaluated in this trial. One thousand and

  2. [The dynamics of calcium distribution in stigma and style of lettuce (Lactuca sativa L.) before and after pollination].

    Science.gov (United States)

    Qiu, Yi Lan; Liu, Ru Shi; Xie, Chao Tian; Yang, Yan Hong; Gu, Li; Tian, Hui Qiao

    2005-08-01

    Potassium antimonite was used to deposit calcium in the stigma and style of lettuce (Lactuca sativa L.) before and after pollination. The stigma of lettuce is two splits. Abundant calcium granules are displayed in the wall of papillae on the receptive surface of stigma before and after pollination, which may facilitate pollen germination. However, a few calcium granules in the wall of epidermis cell on no-receptive surface. Calcium distribution in style presents a gradient in transmitting tissue and parenchyma cells from the top to the base of the style before pollination. After pollination, calcium in transmitting tissue distinctly increased and its gradient distribution became more evident. Pollen tubes grow in the intercellular gaps of transmitting tissue. When pollen tubes grew into transmitting tissue, calcium granules in parenchyma around transmitting tissue decreased, suggesting a calcium movement was controlled by pollen tubes. The calcium gradient distribution also appeared in the trachea of vascular bundle of style. In general, calcium in style displays a feature of time-special distribution: transmitting tissue doesn't need much more calcium that is only stored in the parenchyma before pollination. However, calcium in parenchyma cells may be transported to transmitting tissue and make the latter contain more calcium to form an evident calcium gradient and meet the requirement of pollen tubes directionally growing after pollination. This is the second sample of calcium gradient existing in style, which was found by using potassium antimonite method.

  3. Progestins used in hormonal replacement therapy display different effects in coronary arteries from New Zealand white rabbits

    DEFF Research Database (Denmark)

    Pedersen, Nina G; Pedersen, Susan H; Dalsgaard, Tórur;

    2004-01-01

    OBJECTIVES: The aim of this study was in an animal model to assess the vascular effects of different progestins commonly used in hormonal replacement treatment. METHODS: Fifty-six non-atherosclerotic, ovariectomized New Zealand white rabbits were randomized into seven groups: (1) medroxyprogester......OBJECTIVES: The aim of this study was in an animal model to assess the vascular effects of different progestins commonly used in hormonal replacement treatment. METHODS: Fifty-six non-atherosclerotic, ovariectomized New Zealand white rabbits were randomized into seven groups: (1...... part of the left anterior descending coronary artery were microdissected and mounted for isometric tension recordings in a myograph. The vasoconstrictory responses induced by potassium, endothelin-1, calcium and Nw-nitro-L-arginine methyl ester, and the vasodilatory response induced by acetylcholine......+/-S.E.M.). Treatment with MPA compared to placebo caused an endothelin-1 induced increase of Emax in the distal coronary artery (9.21+/-0.87 versus 6.51+/-0.65 Pcalcium induced increase of pD2 in both coronary arteries (2.98+/-0.19 versus 2.42+/-0.12 P

  4. Postmenopausal hormone replacement therapy--clinical implications

    DEFF Research Database (Denmark)

    Ravn, S H; Rosenberg, J; Bostofte, E

    1994-01-01

    in the urogenital tract. Women at risk of osteoporosis will benefit from hormone replacement therapy. The treatment should start as soon after menopause as possible and it is possible that it should be maintained for life. The treatment may be supplemented with extra calcium intake, vitamin D, and maybe calcitonin....... Physical activity should be promoted, and cigarette smoking reduced if possible. Women at risk of cardiovascular disease will also benefit from hormone replacement therapy. There is overwhelming evidence that hormone therapy will protect against both coronary heart disease and stroke...... suggest that every woman showing any signs of hormone deprivation should be treated with hormone replacement therapy. This includes women with subjective or objective vaso-motor symptoms, genito-urinary symptoms, women at risk of osteoporosis (fast bone losers), and women at risk of cardiovascular...

  5. Muscarinic agonists and potassium currents in guinea-pig myenteric neurones.

    Science.gov (United States)

    Galligan, J J; North, R A; Tokimasa, T

    1989-01-01

    1. Intracellular electrophysiological recordings were obtained from single neurones of the guinea-pig myenteric plexus in vitro. Using single electrode voltage clamp techniques, four distinct potassium currents were described and the effects of muscarinic agonists on these currents were studied. 2. A calcium-dependent potassium current (gKCa) was present in AH neurones at rest, and was much increased following a brief depolarization (50 ms, to 0 mV). Muscarinic agonists reduced both the resting current and the current evoked by depolarization. Pirenzepine competitively antagonized the suppression by muscarine of the calcium-dependent potassium current (or after-hyperpolarization) following an action potential. The dissociation equilibrium constant for pirenzepine was about 10 nM. 3. The conductance of AH neurones increased two to three fold when they were hyperpolarized negative to -90 mV. This inward rectification was blocked by extracellular caesium (2 mM) or rubidium (2 mM), but not by tetraethylammonium (TEA, 40 mM), 4-aminopyridine (100 microM) or cobalt (2 mM). The inward rectification was unaffected by muscarinic agonists. 4. When AH neurones were depolarized from very negative holding potentials (less than -80 mV) a brief outward current was recorded with a duration of about 200 ms. This transient or A current was completely blocked by 4-aminopyridine (100 microM) but was not affected by tetrodotoxin (300 nM), TEA (40 mM) or cobalt (2 mM). Muscarinic agonists did not affect the A current. 5. In S neurones, and in AH neurones in calcium-free solutions, the potassium conductance (in TEA and caesium) behaved according to constant field assumptions. This background conductance was suppressed by muscarinic agonists. 6. It is concluded that the depolarization by muscarinic agonists of myenteric AH neurones is due to a suppression of both a calcium-dependent potassium conductance and a background potassium conductance. Muscarinic depolarization of S neurones

  6. Control of potassium excretion: a Paleolithic perspective.

    Science.gov (United States)

    Halperin, Mitchell L; Cheema-Dhadli, Surinder; Lin, Shih-Hua; Kamel, Kamel S

    2006-07-01

    Regulation of potassium (K) excretion was examined in an experimental setting that reflects the dietary conditions for humans in Paleolithic times (high, episodic intake of K with organic anions; low intake of NaCl), because this is when major control mechanisms were likely to have developed. The major control of K secretion in this setting is to regulate the number of luminal K channels in the cortical collecting duct. Following a KCl load, the K concentration in the medullary interstitial compartment rose; the likely source of this medullary K was its absorption by the H/K-ATPase in the inner medullary collecting duct. As a result of the higher medullary K concentration, the absorption of Na and Cl was inhibited in the loop of Henle, and this led to an increased distal delivery of a sufficient quantity of Na to raise K excretion markedly, while avoiding a large natriuresis. In addition, because K in the diet was accompanied by 'future' bicarbonate, a role for bicarbonate in the control of K secretion via 'selecting' whether aldosterone would be a NaCl-conserving or a kaliuretic hormone is discussed. This way of examining the control of K excretion provides new insights into clinical disorders with an abnormal plasma K concentration secondary to altered K excretion, and also into the pathophysiology of calcium-containing kidney stones.

  7. Frequently Asked Questions on Potassium Iodide (KI)

    Science.gov (United States)

    ... Bioterrorism and Drug Preparedness Frequently Asked Questions on Potassium Iodide (KI) Share Tweet Linkedin Pin it More sharing ... Drug Administration (FDA) issued a final Guidance on Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies) ( ...

  8. Can Diuretics Decrease Your Potassium Level?

    Science.gov (United States)

    ... and Conditions High blood pressure (hypertension) Can diuretics decrease your potassium level? Answers from Sheldon G. Sheps, ... D. Yes, some diuretics — also called water pills — decrease potassium in the blood. Diuretics are commonly used ...

  9. Effect of the partial replacement of sodium chloride by other salts on the formation of volatile compounds during ripening of dry-cured ham.

    Science.gov (United States)

    Armenteros, Mónica; Toldrá, Fidel; Aristoy, M-Concepción; Ventanas, Jesús; Estévez, Mario

    2012-08-01

    The effect of the partial NaCl replacement by other salts (potassium, calcium, and magnesium chloride) on the formation of volatile compounds through the processing of dry-cured ham was studied using solid-phase microextraction (SPME). Three salt formulations were considered, namely, I (100% NaCl), II (50% NaCl and 50% KCl), and III (55% NaCl, 25% KCl, 15% CaCl(2), and 5% MgCl(2)). There was an intense formation of volatile compounds throughout the processing of dry-cured hams, particularly during the "hot-cellar" stage. The differences between treatments were found to be more remarkable at the end of the curing process. Hams from formulations I and II had significantly higher amounts of lipid-derived volatiles such as hexanal than hams from formulation III, whereas the latter had significantly higher amounts of Strecker aldehydes and alcohols. Plausible mechanisms by which salt replacement may affect the generation of volatile compounds include the influence of such replacement on lipid oxidation and proteolysis phenomena. The potential influence of the volatiles profile on the aroma of the products is also addressed in the present paper.

  10. Increased serum potassium affects renal outcomes

    DEFF Research Database (Denmark)

    Miao, Y; Dobre, D; Heerspink, H J Lambers;

    2011-01-01

    To assess the effect of an angiotensin receptor blocker (ARB) on serum potassium and the effect of a serum potassium change on renal outcomes in patients with type 2 diabetes and nephropathy.......To assess the effect of an angiotensin receptor blocker (ARB) on serum potassium and the effect of a serum potassium change on renal outcomes in patients with type 2 diabetes and nephropathy....

  11. 21 CFR 184.1639 - Potassium lactate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium lactate. 184.1639 Section 184.1639 Food... Specific Substances Affirmed as GRAS § 184.1639 Potassium lactate. (a) Potassium lactate (C3H5O3K, CAS Reg. No. 996-31-6) is the potassium salt of lactic acid. It is a hydroscopic, white, odorless solid and...

  12. Depolarization-stimulated /sup 42/K+ efflux in rat aorta is calcium- and cellular volume-dependent

    Energy Technology Data Exchange (ETDEWEB)

    Magliola, L.; Jones, A.W.

    1987-07-01

    The purpose of this study was to investigate the factors controlling membrane permeability to potassium of smooth muscle cells from rat aorta stimulated by depolarization. The increase /sup 42/K+ efflux (change in the rate constant) induced by depolarization (application of high concentrations of potassium chloride) was inhibited significantly by the calcium antagonists diltiazem and nisoldipine. Parallel inhibitory effects on contraction were observed. Diltiazem also inhibited potassium-stimulated /sup 36/Cl- efflux. The addition of 25-150 mM KCl to normal physiologic solution stimulated /sup 42/K+ efflux in a concentration-dependent manner. Diltiazem suppressed potassium-stimulated /sup 42/K+ efflux approximately 90% at 25 mM KCl and approximately 40% at 150 mM KCl. The ability of nisoldipine to inhibit /sup 42/K+ efflux also diminished as the potassium chloride concentration was elevated. The component of efflux that was resistant to calcium antagonists probably resulted from a decrease in the electrochemical gradient for potassium. Cellular water did not change during potassium addition. Substitution of 80 and 150 mM KCl for sodium chloride produced cellular swelling and enhanced potassium-stimulated /sup 42/K+ efflux compared with potassium chloride addition. The addition of sucrose to prevent cellular swelling reduced efflux response to potassium substitution toward that of potassium addition. A hypoosmolar physiologic solution produced an increase in the /sup 42/K+ efflux and a contracture that were both prevented by the addition of sucrose. We concluded that the depolarization-mediated /sup 42/K+ efflux has three components: one is calcium dependent; a second is dependent on cellular volume; and a third is resistant to inhibition by calcium antagonists.

  13. Effects of different phosphorus and potassium fertilization on contents and uptake of macronutrients (N, P, K, Ca, Mg in winter wheat I. Content of macronutrients

    Directory of Open Access Journals (Sweden)

    Renata GAJ

    2014-12-01

    Full Text Available The aim of the study carried out under field conditions was to evaluate the effect of differentiated phosphorus and potassium fertilization level on nutritional status of winter wheat at stem elongation (BBCH 31 and flowering (BBCH 65 development stages as well as on macronutrient contents in yield obtained (grain and straw. The research was conducted in 2007-2010, within an individual agricultural holding, on lessive soil with medium and high richness in potassium and phosphorus, respectively. The contents of nitrogen, phosphorus, potassium, magnesium and calcium in wheat changed depending on the organ assessed and plant development stage. At BBCH 31, regardless fertilization level, the plants observed were malnourished with potassium, phosphorus and calcium and at the control site also with nitrogen. Furthermore, there were found significant correlation relationships among the contents of nutrient pairs: nitrogen-potassium, nitrogen-phosphorus, nitrogen-magnesium and nitrogen-calcium. The content of nitrogen in wheat grain and straw differed mainly due to weather conditions during the study. Irrespective of the years of observation, differentiated rates of P and K applied had no significant effect on N accumulation in wheat at full ripening stage. In contrast to nitrogen, the level of P and K fertilization significantly differentiated the contents of phosphorus, potassium and magnesium in wheat grain and straw. In case of calcium, the effect of fertilization factor was indicated only as regards the content of this nutrient in grain.

  14. 21 CFR 182.3640 - Potassium sorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium sorbate. 182.3640 Section 182.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Potassium sorbate. (a) Product. Potassium sorbate. (b) Conditions of use. This substance is...

  15. 21 CFR 582.1643 - Potassium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium sulfate. 582.1643 Section 582.1643 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1643 Potassium sulfate. (a) Product. Potassium sulfate. (b) Conditions of use....

  16. 21 CFR 172.730 - Potassium bromate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium bromate. 172.730 Section 172.730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Specific Usage Additives § 172.730 Potassium bromate. The food additive potassium bromate may be...

  17. 21 CFR 582.6625 - Potassium citrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium citrate. 582.6625 Section 582.6625 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium citrate. (a) Product. Potassium citrate. (b) Conditions of use. This substance is...

  18. 21 CFR 582.1625 - Potassium citrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium citrate. 582.1625 Section 582.1625 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1625 Potassium citrate. (a) Product. Potassium citrate. (b) Conditions of use....

  19. 21 CFR 184.1643 - Potassium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium sulfate. 184.1643 Section 184.1643 Food... Specific Substances Affirmed as GRAS § 184.1643 Potassium sulfate. (a) Potassium sulfate (K2SO4, CAS Reg... having a bitter, saline taste. It is prepared by the neutralization of sulfuric acid with...

  20. 21 CFR 582.3640 - Potassium sorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium sorbate. 582.3640 Section 582.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL....3640 Potassium sorbate. (a) Product. Potassium sorbate. (b) Conditions of use. This substance...

  1. 21 CFR 582.5634 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium iodide. 582.5634 Section 582.5634 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5634 Potassium iodide. (a) Product. Potassium iodide. (b) Tolerance. 0.01 percent....

  2. 21 CFR 582.7610 - Potassium alginate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium alginate. 582.7610 Section 582.7610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Potassium alginate. (a) Product. Potassium alginate. (b) Conditions of use. This substance is...

  3. 21 CFR 172.160 - Potassium nitrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium nitrate. 172.160 Section 172.160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a...

  4. Calcium sparks in the intact gerbil spiral modiolar artery

    Directory of Open Access Journals (Sweden)

    Berge Samantha

    2011-08-01

    Full Text Available Abstract Background Calcium sparks are ryanodine receptor mediated transient calcium signals that have been shown to hyperpolarize the membrane potential by activating large conductance calcium activated potassium (BK channels in vascular smooth muscle cells. Along with voltage-dependent calcium channels, they form a signaling unit that has a vasodilatory influence on vascular diameter and regulation of myogenic tone. The existence and role of calcium sparks has hitherto been unexplored in the spiral modiolar artery, the end artery that controls blood flow to the cochlea. The goal of the present study was to determine the presence and properties of calcium sparks in the intact gerbil spiral modiolar artery. Results Calcium sparks were recorded from smooth muscle cells of intact arteries loaded with fluo-4 AM. Calcium sparks occurred with a frequency of 2.6 Hz, a rise time of 17 ms and a time to half-decay of 20 ms. Ryanodine reduced spark frequency within 3 min from 2.6 to 0.6 Hz. Caffeine (1 mM increased spark frequency from 2.3 to 3.3 Hz and prolonged rise and half-decay times from 17 to 19 ms and from 20 to 23 ms, respectively. Elevation of potassium (3.6 to 37.5 mM, presumably via depolarization, increased spark frequency from 2.4 to 3.2 Hz. Neither ryanodine nor depolarization changed rise or decay times. Conclusions This is the first characterization of calcium sparks in smooth muscle cells of the spiral modiolar artery. The results suggest that calcium sparks may regulate the diameter of the spiral modiolar artery and cochlear blood flow.

  5. [Effects of fertilization on aquic brown soil potassium budget and crop potassium allocation].

    Science.gov (United States)

    Jiang, Zishao; Yu, Wantai; Zhang, Lu

    2006-12-01

    Through a consecutive 15 years field trial on the aquic brown soil in Shenyang suburb of Northeast China, this paper studied the soil potassium budget and crop potassium allocation under effects of different fertilization systems. The results indicated that applying nitrogen or nitrogen plus phosphorous without potassium application accelerated the deficit of soil potassium. The potassium concentration in soybean grain and stalk was higher under potassium application than with no potassium supply, while that in maize grain had no significant difference in different fertilization treatments. The reutilization of recycled nutrients in farming system could mitigate the deficit of soil potassium budget, and such reutilization assorted with appropriate amount of potassium fertilization could not only produce high crop yield, but also balance soil potassium budget.

  6. The effect of foliar feeding of potassium salts and urea in spinach on gas exchange, leaf yield and quality

    Directory of Open Access Journals (Sweden)

    Edward Borowski

    2012-12-01

    Full Text Available In a pot experiment conducted in a phytotron, the effectiveness of foliar feeding of different potassium salts, with and without the addition of 0.5% CO(NH22, in spinach (Spinacia oleracea L. was investigated. Potassium was applied 3 times in the form of 1% solutions KCl, KNO3, K2SO4 and C6H5K3O7•H2O, compared to water as the control treatment. The obtained results show that foliar feeding of potassium salts in spinach is an efficient method of supplementing the level of K+ in plants during vegetation. Plants fed with KNO3 had the highest content of potassium in leaves, and those fertilized with K2SO4, C6H5K3O7 × H2O and KCl had an only slightly lower potassium content. The application of potassium salts resulted in more intensive gas exchange in leaves (stomatal conductance, photosynthesis, transpiration and, as a consequence of that, increased leaf yield. Potassium nitrate and citrate influenced most effectively the abovementioned processes. The treatment of spinach with potassium salts resulted in an increased content of protein, chlorophyll, carotenoids, nitrates and iron as well as a decreased content of vitamin C and calcium in leaves.

  7. Aeronautical Information System Replacement -

    Data.gov (United States)

    Department of Transportation — Aeronautical Information System Replacement is a web-enabled, automation means for the collection and distribution of Service B messages, weather information, flight...

  8. Replacing American Breakfast Foods with Ready-To-Eat (RTE) Cereals Increases Consumption of Key Food Groups and Nutrients among US Children and Adults: Results of an NHANES Modeling Study.

    Science.gov (United States)

    Rehm, Colin D; Drewnowski, Adam

    2017-09-13

    Replacing the typical American breakfast with ready-to-eat cereals (RTECs) may improve diet quality. Our goal was to assess the impact of RTECs on diet quality measures for different age groups, using substitution modeling. Dietary intakes came from the 2007-2010 National Health and Examination Surveys (NHANES; n = 18,112). All breakfast foods, excluding beverages, were replaced on a per calorie basis, with frequency-weighted and age/race specific RTECs. Model 1 replaced foods with RTECs alone; Model 2 replaced foods with RTECs and milk. Diet quality measures were based on desirable food groups and nutrients, Healthy Eating Index (HEI)-2010 scores, and estimated diet costs. Model 1 diets were significantly higher in whole grains (+84.6%), fiber (+14.3%), vitamin D (+14.0%), iron (+54.5%) and folic acid (+104.6%), as compared to observed diets. Model 2 diets were additionally higher in dairy (+15.8%), calcium (+11.3%) and potassium (+3.95%). In Model 1, added sugar increased (+5.0%), but solid fats declined (-10.9%). Energy from solid fats and added sugars declined (-3.2%) in both models. Model 2 offered higher diet quality (57.1 vs. 54.6, p-value < 0.01) at a lower cost ($6.70 vs. $6.92; p < 0.01), compared to observed diets. Substitution modeling of NHANES data can assess the nutritional and economic impact of dietary guidance.

  9. Replacing American Breakfast Foods with Ready-To-Eat (RTE Cereals Increases Consumption of Key Food Groups and Nutrients among US Children and Adults: Results of an NHANES Modeling Study

    Directory of Open Access Journals (Sweden)

    Colin D. Rehm

    2017-09-01

    Full Text Available Replacing the typical American breakfast with ready-to-eat cereals (RTECs may improve diet quality. Our goal was to assess the impact of RTECs on diet quality measures for different age groups, using substitution modeling. Dietary intakes came from the 2007–2010 National Health and Examination Surveys (NHANES; n = 18,112. All breakfast foods, excluding beverages, were replaced on a per calorie basis, with frequency-weighted and age/race specific RTECs. Model 1 replaced foods with RTECs alone; Model 2 replaced foods with RTECs and milk. Diet quality measures were based on desirable food groups and nutrients, Healthy Eating Index (HEI-2010 scores, and estimated diet costs. Model 1 diets were significantly higher in whole grains (+84.6%, fiber (+14.3%, vitamin D (+14.0%, iron (+54.5% and folic acid (+104.6%, as compared to observed diets. Model 2 diets were additionally higher in dairy (+15.8%, calcium (+11.3% and potassium (+3.95%. In Model 1, added sugar increased (+5.0%, but solid fats declined (−10.9%. Energy from solid fats and added sugars declined (−3.2% in both models. Model 2 offered higher diet quality (57.1 vs. 54.6, p-value < 0.01 at a lower cost ($6.70 vs. $6.92; p < 0.01, compared to observed diets. Substitution modeling of NHANES data can assess the nutritional and economic impact of dietary guidance.

  10. Dysbalance of astrocyte calcium under hyperammonemic conditions.

    Directory of Open Access Journals (Sweden)

    Nicole Haack

    Full Text Available Increased brain ammonium (NH4(+/NH3 plays a central role in the manifestation of hepatic encephalopathy (HE, a complex syndrome associated with neurological and psychiatric alterations, which is primarily a disorder of astrocytes. Here, we analysed the influence of NH4(+/NH3 on the calcium concentration of astrocytes in situ and studied the underlying mechanisms of NH4(+/NH3-evoked calcium changes, employing fluorescence imaging with Fura-2 in acute tissue slices derived from different regions of the mouse brain. In the hippocampal stratum radiatum, perfusion with 5 mM NH4(+/NH3 for 30 minutes caused a transient calcium increase in about 40% of astrocytes lasting about 10 minutes. Furthermore, the vast majority of astrocytes (∼ 90% experienced a persistent calcium increase by ∼ 50 nM. This persistent increase was already evoked at concentrations of 1-2 mM NH4(+/NH3, developed within 10-20 minutes and was maintained as long as the NH4(+/NH3 was present. Qualitatively similar changes were observed in astrocytes of different neocortical regions as well as in cerebellar Bergmann glia. Inhibition of glutamine synthetase resulted in significantly larger calcium increases in response to NH4(+/NH3, indicating that glutamine accumulation was not a primary cause. Calcium increases were not mimicked by changes in intracellular pH. Pharmacological inhibition of voltage-gated sodium channels, sodium-potassium-chloride-cotransporters (NKCC, the reverse mode of sodium/calcium exchange (NCX, AMPA- or mGluR5-receptors did not dampen NH4(+/NH3-induced calcium increases. They were, however, significantly reduced by inhibition of NMDA receptors and depletion of intracellular calcium stores. Taken together, our measurements show that sustained exposure to NH4(+/NH3 causes a sustained increase in intracellular calcium in astrocytes in situ, which is partly dependent on NMDA receptor activation and on release of calcium from intracellular stores. Our study

  11. Thanatochemistry: Study of vitreous humor potassium

    Directory of Open Access Journals (Sweden)

    Nilesh Keshav Tumram

    2014-12-01

    Full Text Available This study has been carried out to determine the death interval from the biochemical parameter of vitreous potassium. In 308 medicolegal cases vitreous humor was taken and analyzed for potassium with known time of death. There was a linear rise in potassium concentration with increasing death interval. Regression equation was calculated for the same. The study indicates that potassium levels in vitreous for determining death interval are useful and can afford a good method of determining the death interval along with other traditional methods. Also the previously established formulae for estimating death interval from vitreous potassium were also studied.

  12. Produção de biomassa e rizomas e incidência de "Metsubure" em taro submetido a doses de potássio com e sem adição de cálcio Biomass accumulation, yield and "Metsubure" incidence in taro corms submitted to potassium rates, with and without calcium application

    Directory of Open Access Journals (Sweden)

    Francisco HF Pereira

    2006-03-01

    Full Text Available Avaliou-se o efeito de doses crescentes de potássio (K, em solo com e sem aplicação de cálcio (Ca, na produção de biomassa, produção de rizomas, teores de K e Ca e incidência de "Metsubure" em rizomas de taro. O experimento foi conduzido em vasos contendo 10 L de solo, em casa de vegetação, de 19/10/2002 a 20/07/2003, com o taro 'Chinês' (BGH 5928. Foram avaliadas cinco doses de K (0; 150; 300; 600 e 1.200 mg K2O kg-1 de solo, sem e com adição de Ca (0 e 232 mg Ca kg-1 de solo, dispostas no delineamento inteiramente casualizado, em esquema fatorial 5 x 2, com quatro repetições. Produções de biomassa e de rizomas apresentaram comportamento semelhante em resposta às doses de K, em presença e ausência da adição do Ca. Valores máximos de biomassa seca e produção de rizomas foram verificados com a adição de Ca nas doses de 794 e 760 mg K2O kg-1 de solo, respectivamente. Sob baixa dose de K, as massas secas de rizomas e totais, a produção de massa fresca e o número de rizomas-filho por planta foram maiores na ausência do que presença de Ca, sendo esse comportamento invertido a partir das doses de K2O de 85; 46; 202 e 578 mg kg-1 de solo, respectivamente. Na ausência da adição de Ca incrementos na dose de K promoveram redução da concentração de Ca nos rizomas-filho; a concentração de K nesses rizomas aumentou com o incremento na dose de K, independentemente da adição de Ca. Na ausência de adição de Ca e nas doses de 600 e 1.200 mg K2O kg-1 de solo constatou-se a incidência do sintoma de "Metsubure" em 6,56 e 9,84% dos rizomas-filho, respectivamente.The biomass accumulation (cormels and total plant dry weight, yield (fresh weight and number of cormels and "Metsubure" incidence in taro cormels was evaluated on plants submitted to distinct potassium (K fertilizer rates, with and without calcium (Ca application. The experiment was conduced in a glasshouse from 10/19/2002 to 07/20/2003, with the taro 'Chin

  13. Processes modulating calcium distribution in citrus leaves. An investigation using x-ray microanalysis with strontium as a tracer.

    Science.gov (United States)

    Storey, Richard; Leigh, Roger A

    2004-11-01

    Citrus leaves accumulate large amounts of calcium that must be compartmented effectively to prevent stomatal closure by extracellular Ca2+ and interference with Ca(2+)-based cell signaling pathways. Using x-ray microanalysis, the distribution of calcium between vacuoles in different cell types of leaves of rough lemon (Citrus jambhiri Lush.) was investigated. Calcium was accumulated principally in palisade, spongy mesophyll, and crystal-containing idioblast cells. It was low in epidermal and bundle sheath cells. Potassium showed the reverse distribution. Rubidium and strontium were used as tracers to examine the pathways by which potassium and calcium reached these cells. Comparisons of strontium and calcium distribution indicated that strontium is a good tracer for calcium, but rubidium did not mirror the potassium distribution pattern. The amount of strontium accumulated was highest in palisade cells, lowest in bundle sheath and epidermal cells, and intermediate in the spongy mesophyll. Accumulation of strontium in palisade and spongy mesophyll was accompanied by loss of potassium from these cells and its accumulation in the bundle sheath. Strontium moved apoplastically from the xylem to all cell types, and manipulation of water loss from the adaxial leaf surface suggested that diffusion is responsible for strontium movement to this side of the leaf. The results highlight the importance of palisade and spongy mesophyll as repositories for calcium and suggest that calcium distribution between different cell types is the result of differential rates of uptake. This tracer technique can provide important information about the ion uptake and accumulation properties of cells in intact leaves.

  14. Use of Potassium Citrate to Reduce the Risk of Renal Stone Formation During Spaceflight

    Science.gov (United States)

    Whitson, P. A.; Pietrzyk, R. A.; Sams, C. F.; Jones, J. A.; Nelman-Gonzalez, M.; Hudson, E. K.

    2008-01-01

    Introduction: NASA s Vision for Space Exploration centers on exploration class missions including the goals of returning to the moon and landing on Mars. One of NASA s objectives is to focus research on astronaut health and the development of countermeasures that will protect crewmembers during long duration voyages. Exposure to microgravity affects human physiology and results in changes in the urinary chemical composition favoring urinary supersaturation and an increased risk of stone formation. Nephrolithiasis is a multifactorial disease and development of a renal stone is significantly influenced by both dietary and environmental factors. Previous results from long duration Mir and short duration Shuttle missions have shown decreased urine volume, pH, and citrate levels and increased calcium. Citrate, an important inhibitor of calcium-containing stones, binds with urinary calcium reducing the amount of calcium available to form stones. Citrate inhibits renal stone recurrence by preventing crystal growth, aggregation, and nucleation and is one of the most common therapeutic agents used to prevent stone formation. Methods: Thirty long duration crewmembers (29 male, 1 female) participated in this study. 24-hour urines were collected and dietary monitoring was performed pre, in, and postflight. Crewmembers in the treatment group received two potassium citrate (KCIT) pills, 10 mEq/pill, ingested daily beginning 3 days before launch, all inflight days and through 14 days postflight. Urinary biochemical and dietary analyses were completed. Results: KCIT treated subjects exhibited decreased urinary calcium excretion and maintained the levels of calcium oxalate supersaturation risk at their preflight levels. The increased urinary pH levels in these subjects reduced the risk of uric acid stones. Discussion: The current study investigated the use of potassium citrate as a countermeasure to minimize the risk of stone formation during ISS missions. Results suggest that

  15. Octreotide enhances positive calcium balance in Duchenne muscular dystrophy.

    Science.gov (United States)

    Nutting, D F; Schriock, E A; Palmieri, G M; Bittle, J B; Elmendorf, B J; Horner, L H; Edwards, M C; Griffin, J W; Sacks, H S; Bertorini, T E

    1995-09-01

    Although receptors for somatostatin are found in bone cells, the effect of somatostatin analogs on calcium metabolism is unknown. The authors studied, in a metabolic ward, the effect of octreotide (a long-acting somatostatin analog) and a placebo in two 6-day calcium balance periods in 8 children with Duchenne muscular dystrophy. As expected, octreotide (2 micrograms/kg, subcutaneously, every 8 hours) reduced serum growth hormone and somatomedin (IGF-1) to levels found in growth hormone deficiency. Octreotide enhanced calcium retention by 30% (96 mg daily [P < 0.04]) in 7 boys for whom complete data (diet, urine, and fecal calcium) were available. In 6 children with urinary calcium excretion (Uca) greater than 50 mg daily, octreotide markedly lowered Uca, from 114 +/- 23 mg daily to 61 +/- 9 mg daily (P < 0.03). Calcium retention occurred in patients with or without initial hypercalciuria, but the higher the basal Uca, the greater was the inhibition by octreotide (r = 0.79; P < 0.03). Inactive, nonambulatory patients had a more pronounced response of Uca to octreotide (P < 0.02). Octreotide caused a mild, nonsignificant reduction in fecal calcium, with no major changes in serum calcium, phosphorus, parathyroid hormone, urinary excretion of sodium and potassium, or in creatinine clearance. Based on the current observations and the presence of receptors for somatostatin in bone cells, this hormone may have, at least on a short-term basis, an anabolic effect on calcium, perhaps favoring its deposition in bone.

  16. The potassium channel KCa3.1 as new therapeutic target for the prevention of obliterative airway disease

    DEFF Research Database (Denmark)

    Hua, Xiaoqin; Deuse, Tobias; Chen, Yi-Je

    2013-01-01

    The calcium-activated potassium channel KCa3.1 is critically involved in T-cell activation as well as in the proliferation of smooth muscle cells and fibroblasts. We sought to investigate whether KCa3.1 contributes to the pathogenesis of obliterative airway disease (OAD) and whether knockout...

  17. Effect of genistein on voltage-gated potassium channels in guinea pig proximal colon smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Shi-Ying Li; Bin-Bin Huang; Shou Ouyang

    2006-01-01

    AIM: To investigate the action of genistein (GST), a broad spectrum tyrosine kinase inhibitor, on voltagegated potassium channels in guinea pig proximal colon smooth muscle cells.METHODS: Smooth muscle cells in guinea pig proximal colon were enzymatically isolated. Nystatin-perforated whole cell patch clamp technique was used to record potassium currents including fast transient outward current (IKto) and delayed rectifier current (IKdr), two of which were isolated pharmacologically with 10 mmol/L tetraethylammonium or 5 mmol/L 4-aminopyridine.Contamination of calcium-dependent potassium currents was minimized with no calcium and 0.2 mmol/L CdCl2 in an external solution.RESULTS: GST (10-100 μmol/L) reversibly and dosedependently reduced the peak amplitude of IKto with an IC50value of 22.0±6.9 μmol/L. To a lesser extent, IKdr was also inhibited in both peak current and sustained current.GST could not totally block the outward potassium current as a fraction of the outWard potassium current,which was insensitive to GST. GST had no effect on the steady-state activation (n = 6) and inactivation kinetics(n =6) of IKto. Sodium orthovanadate (1 mmol/L), a potent inhibitor of tyrosine phosphatase, significantly inhibited GST-induced inhibition (P< 0.05).CONCLUSION: GST can dose-dependently and reversibly block voltage-gated potassium channels in guinea pig proximal colon smooth muscle cells.

  18. 钠钾镁钙葡萄糖注射液应用于烧伤休克液体复苏的临床疗效评估——前瞻性、随机、单盲、阳性药物对照、多中心临床试验%Clinical evaluation of sodium potassium magnesium calcium and glucose injection during fluid resuscitation of burn shock: a prospective, randomized, single-blinded, positive drug controlled, multicentre clinical trial

    Institute of Scientific and Technical Information of China (English)

    柴家科; 李利根; 罗高兴; 沈光裕; 张庆富; 王玉莲; 霍然; 牛希华; 孙海宁

    2013-01-01

    Objective To evaluate the efficacy and safety of sodium potassium magnesium calcium and glucose injection(Le Jia (R)) comparing with sodium lactated ringer's solution for burn resuscitation.Methods 198 burned patients who met the criterion were performed fluid resuscitation during the first 6 h after injury.All patients who were enrolled in this study had been assigned assigned either the sodium potassium magnesium calcium and glucose injection group (test group) or the sodium lactated ringer's group (control group) according to random number table.Before the fluid resuscitation according to 1970 National Conference of Burn Injuries formula,the clinical index such as routine blood count,liver and kidney functions,blood biochemistry and coagulation function were detected.The hemodynamic index,arterial blood gas and serum glucose levels were monitored during fluid infusion,and all blood lab indexes were detected at the end of the first and second 24 h after resuscitation beginning.The efficacy index is the changes of serum electrolyte,arterial blood lactate,blood gas and serum glucose levels after resuscitation of two different electrolyte solution.And the safety index is the incidence and specific situation of adverse drug reaction.Results Comprehensive analysis was performed from the aspects of maintaining of serum electrolyte,acid-base equilibrium,changes of blood lactate and glucose levels.No statistically significant difference was found between the two groups.In safety evaluation,safe cases in test group were 99(100%) as well as in control group.No statistically significant difference was found in safety evaluation.Conclusions Sodium potassium magnesium calcium and glucose injection (Le Jia (R)) has the comparative efficacy and safety to sodium lactated ringer's solution,the most commonly used in clinic for burn resuscitation.%目的 以乳酸钠林格注射液为对照,验证钠钾镁钙葡萄糖注射液(乐加(R))用于烧伤休克液体复苏方面

  19. Potential Population-Level Nutritional Impact of Replacing Whole and Reduced-Fat Milk With Low-Fat and Skim Milk Among US Children Aged 2–19 Years

    Science.gov (United States)

    Rehm, Colin D.; Drewnowski, Adam; Monsivais, Pablo

    2015-01-01

    Objective Dietary guidance emphasizes plain low-fat and skim milk over whole, reduced-fat, and flavored milk (milk eligible for replacement [MER]). The objective of this study was to evaluate the population-level impact of such a change on energy, macronutrient and nutrient intakes, and diet cost. Design Cross-sectional modeling study. Setting Data from the 2001–2002 and 2003–2004 National Health and Nutrition Examination Survey. Participants A total of 8,112 children aged 2–19 years. Main Outcome Measures Energy, macronutrient, and micronutrient intake before and after replacement of MER with low-fat or skim milk. Analysis Survey-weighted linear regression models. Results Milk eligible for replacement accounted for 46% of dairy servings. Among MER consumers, replacement with skim or low-fat milk would lead to a projected reduction in energy of 113 (95% confidence interval [CI], 107–119) and 77 (95% CI, 73–82) kcal/d and percent energy from saturated fat by an absolute value of 2.5% of total energy (95% CI, 2.4–2.6) and 1.4% (95% CI, 1.3–1.5), respectively. Replacement of MER does not change diet costs or calcium and potassium intake. Conclusions Substitution of MER has the potential to reduce energy and total and saturated fat intake with no impact on diet costs or micronutrient density. The feasibility of such replacement has not been examined and there may be negative consequences if replacement is done with non-nutrient–rich beverages. PMID:25528079

  20. Potential population-level nutritional impact of replacing whole and reduced-fat milk with low-fat and skim milk among US children aged 2-19 years.

    Science.gov (United States)

    Rehm, Colin D; Drewnowski, Adam; Monsivais, Pablo

    2015-01-01

    Dietary guidance emphasizes plain low-fat and skim milk over whole, reduced-fat, and flavored milk (milk eligible for replacement [MER]). The objective of this study was to evaluate the population-level impact of such a change on energy, macronutrient and nutrient intakes, and diet cost. Cross-sectional modeling study. Data from the 2001-2002 and 2003-2004 National Health and Nutrition Examination Survey. A total of 8,112 children aged 2-19 years. Energy, macronutrient, and micronutrient intake before and after replacement of MER with low-fat or skim milk. Survey-weighted linear regression models. Milk eligible for replacement accounted for 46% of dairy servings. Among MER consumers, replacement with skim or low-fat milk would lead to a projected reduction in energy of 113 (95% confidence interval [CI], 107-119) and 77 (95% CI, 73-82) kcal/d and percent energy from saturated fat by an absolute value of 2.5% of total energy (95% CI, 2.4-2.6) and 1.4% (95% CI, 1.3-1.5), respectively. Replacement of MER does not change diet costs or calcium and potassium intake. Substitution of MER has the potential to reduce energy and total and saturated fat intake with no impact on diet costs or micronutrient density. The feasibility of such replacement has not been examined and there may be negative consequences if replacement is done with non-nutrient-rich beverages. Copyright © 2015. Published by Elsevier Inc.

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

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Yunpeng Cao

    2008-01-01

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

  2. Radiation Source Replacement Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, Jeffrey W.; Moran, Traci L.; Bond, Leonard J.

    2010-12-01

    This report summarizes a Radiation Source Replacement Workshop in Houston Texas on October 27-28, 2010, which provided a forum for industry and researchers to exchange information and to discuss the issues relating to replacement of AmBe, and potentially other isotope sources used in well logging.

  3. Sewage sludge as a deposit inhibitor when co-fired with high potassium fuels

    Energy Technology Data Exchange (ETDEWEB)

    Elled, A.L. [Department of Energy and Environment, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); University College of Boraas, SE-50190 Boraas (Sweden); Davidsson, K.O.; Aamand, L.E. [Department of Energy and Environment, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)

    2010-11-15

    The objective of this work is to survey the fate of potassium in the gas phase of a fluidised bed boiler and gain deeper understanding of the involved mechanisms during co-firing of municipal sewage sludge with biomass containing high amounts of potassium and chlorine. The results show that formation of alkali chlorides in the flue gas and corrosive deposits on heat transfer surfaces can be controlled by addition of municipal sewage sludge even though the fuel is highly contaminated with chlorine. The beneficial effects are partly due to the content of sulphur in the sludge, partly to the properties of the sludge ash. The sludge ash consists of both crystalline and amorphous phases. It contains silica, aluminium, calcium, iron and phosphorus which all are involved in the capture of potassium. (author)

  4. Calcium sensing in exocytosis

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wu, Bingbing; Han, Weiping

    2012-01-01

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

  5. Plasma Potassium Levels in Healthy Prehypertension Subjects and the Role of A High Potassium Drink.

    Science.gov (United States)

    Farapti, Farapti; Sayogo, Savitri; Siregar, Parlindungan

    2017-02-24

    Most populations around the world consume less than the recommended levels of potassium. Long term low potassium intake could lead to decreased plasma potassium levels and induce hypokalemia. The increasing of plasma potassium levels 0,2-0,4 mmol/L by improving potassium intake decreased significantly blood pressure (BP). Assessing plasma potassium levels in healthy people related to potassium intake have not been studied. In this study, we analysed plasma potassium levels in prehypertension (PHT) subjects and to evaluate the effect of tender coconut water (TCW) as a high potassium drink on plasma potassium levels in PHT adults. Thirthy-two female aged 25-44 years were randomly allocated to 14 days on TCW or water in a parallel randomized clinical trial . The treatment (T) group received TCW 300 ml twice daily and the control (C) group received water 300 ml twice daily too. At baseline, plasma potassium levels was 3.71±0.41 mmol/L, and 22.58% were categorized as hypokalemia. After 14 days treatment, potassium plasma level between T and C groups were not significantly different (p=0,247). The change of plasma potassium levels in both groups showed tendency to increase but not statistically significant (p=0.166). In healthy prehypertension women, the low levels of potassium plasma may be caused by low potassium intake for long time and intervension with TCW 300 ml twice daily for 14 consecutive days has not proven yet to increase plasma potassium levels. It is necessary to give higher dose and longer time to increase potassium plasma in low potassium plasma level subjects.

  6. The inhibitory effects of potassium chloride versus potassium silicate application on (137)Cs uptake by rice.

    Science.gov (United States)

    Fujimura, Shigeto; Yoshioka, Kunio; Ota, Takeshi; Ishikawa, Tetsuya; Sato, Makoto; Satou, Mutsuto

    2016-03-01

    After the accident at the Fukushima Dai-ichi Nuclear Power Plant owned by the Tokyo Electric Power Company on 11 March 2011, potassium fertilizer was applied to agricultural fields in the southern Tohoku and northern Kanto regions of Japan to reduce the uptake of radiocesium by crops. In this study, we examined the effects of two types of potassium fertilizers, potassium chloride (a readily available potassium fertilizer) and potassium silicate (a slow-release potassium fertilizer), as well as a split application of potassium, on the accumulation of (137)Cs by rice plants in two pot experiments. The (137)Cs concentrations in the brown rice and in the above-ground plants were significantly lower after potassium chloride application than after potassium silicate application. The potassium ion (K(+)) concentrations in soil solutions sampled 9 and 21 d after transplanting were significantly higher for the potassium chloride application than for the potassium silicate application. The K(+) concentrations in soil solutions observed in the application of potassium silicate were similar to those in the treatment when no potassium was applied. This finding indicates that the application of potassium silicate did not sufficiently increase the available K(+) for rice plants in the soil, which led to a greater uptake of (137)Cs after the potassium silicate application than after the application of potassium chloride. The (137)Cs concentration in brown rice was higher in the split application of potassium fertilizer with the second application at the full heading stage than that without split application and the split application with the second application before heading. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Noradrenaline blocks potassium conductance in rat dentate granule cells in vitro.

    Science.gov (United States)

    Haas, H L; Rose, G M

    1987-07-22

    The actions of noradrenaline and the beta-adrenergic agonist, isoproterenol, were studied on the dentate gyrus in hippocampal slices from rats using extra- and intracellular recording. These agents facilitated field EPSPs (excitatory postsynaptic potentials) and population spikes evoked by perforant path stimulation. Intracellular recording revealed an attenuation of the long lasting afterhyperpolarization (AHP) and the accommodation of cell discharge in response to depolarizing current injection. It is suggested that beta-receptor activation blocks a calcium-dependent potassium current.

  8. Imaging calcium in neurons.

    Science.gov (United States)

    Grienberger, Christine; Konnerth, Arthur

    2012-03-08

    Calcium ions generate versatile intracellular signals that control key functions in all types of neurons. Imaging calcium in neurons is particularly important because calcium signals exert their highly specific functions in well-defined cellular subcompartments. In this Primer, we briefly review the general mechanisms of neuronal calcium signaling. We then introduce the calcium imaging devices, including confocal and two-photon microscopy as well as miniaturized devices that are used in freely moving animals. We provide an overview of the classical chemical fluorescent calcium indicators and of the protein-based genetically encoded calcium indicators. Using application examples, we introduce new developments in the field, such as calcium imaging in awake, behaving animals and the use of calcium imaging for mapping single spine sensory inputs in cortical neurons in vivo. We conclude by providing an outlook on the prospects of calcium imaging for the analysis of neuronal signaling and plasticity in various animal models.

  9. Inhibition of calcium currents in cultured rat dorsal root ganglion neurones by (-)-baclofen.

    OpenAIRE

    Dolphin, A C; Scott, R.H.

    1986-01-01

    Voltage-dependent inward calcium currents (ICa) activated in cultured rat dorsal root ganglion neurones were reversibly reduced in a dose-dependent manner by (-)-baclofen (10 microM to 100 microM). Baclofen (100 microM) reduced the calcium-dependent slow outward potassium current (IK(Ca)). This current was abolished in calcium-free medium and by 300 microM cadmium chloride. The action of baclofen on IK(Ca) was reduced when the calcium concentration in the medium was increased from 5 mM to 30 ...

  10. Intracellular calcium modulates basolateral K(+)-permeability in frog skin epithelium

    DEFF Research Database (Denmark)

    Brodin, Birger; Rytved, K A; Nielsen, R

    1994-01-01

    Cytosolic calcium ([Ca2+]i) has been suggested as a key modulator in the regulation of active sodium transport across electrically "tight" (high resistance) epithelia. In this study we investigated the effects of calcium on cellular electrophysiological parameters in a classical model tissue......, the frog skin. [Ca2+]i was measured with fura-2 in an epifluorescence microscope setup. An inhibition of basolateral potassium permeability was observed when cytosolic calcium was increased. This inhibition was reversible upon removal of calcium from the serosal solution....

  11. Effects of caffeine on intracellular calcium, calcium current and calcium-dependent potassium current in anterior pituitary GH3 cells.

    Science.gov (United States)

    Kramer, R H; Mokkapatti, R; Levitan, E S

    1994-01-01

    Caffeine elicits physiological responses in a variety of cell types by triggering the mobilization of Ca2+ from intracellular organelles. Here we investigate the effects of caffeine on intracellular Ca2+ concentration ([Ca2+]i) and ionic currents in anterior pituitary cells (GH3) cells. Caffeine has a biphasic effect on Ca(2+)-activated K+ current [IK(Ca)]: it induces a transient increase superimposed upon a sustained inhibition. While the transient increase coincides with a rise in [Ca2+]i, the sustained inhibition of IK(Ca) is correlated with a sustained inhibition of the L-type Ca2+ current. The L-type Ca2+ current is also inhibited by other agents that mobilize intracellular Ca2+, including thyrotropin releasing hormone (TRH) and ryanodine, but in a matter distinct from caffeine. Unlike the caffeine effect, the TRH-induced inhibition "washes-out" under whole-cell patch-clamp conditions and is eliminated by intracellular Ca2+ chelators. Likewise, the ryanodine-induced inhibition desensitizes while the caffeine-induced inhibition does not. Simultaneous [Ca2+]i and Ca2+ current measurements show that caffeine can inhibit Ca2+ current without changing [Ca2+]i. Single-channel recordings show that caffeine reduces mean open time without affecting single-channel conductance of L-type channels. Hence the effects of caffeine on ion channels in GH3 cells are attributable both to mobilization of intracellular Ca2+ and to a direct effect on the gating of L-type Ca2+ channels.

  12. Effects of arsenic trioxide on voltage-dependent potassium channels and on cell proliferation of human multiple myeloma cells

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jin; WANG Wei; WEI Qing-fang; FENG Tie-ming; TAN Li-jun; YANG Bao-feng

    2007-01-01

    @@ Arsenic trioxide (ATO) can induce cellular apoptosis and inhibit the activities of multiple myeloma (MM)cells in vitro,1 but how it works is not very clear. Recent studies showed that ATO worked on the voltagedependent potassium channel and L-type calcium channel in myocardial cells,2-5 but the effect of ATO on ion channels of tumor cells was rarely reported. As the potassium channel plays an important role in controlling cell proliferation,6 we studied the effects of ATO on the voltage-dependent potassium current (Ikv) of the voltage-dependent potassium channel in an MM cell line,and probed into the relationship between changes of the Ikv caused by ATO and cell proliferation.

  13. Potassium Intake, Bioavailability, Hypertension, and Glucose Control

    Directory of Open Access Journals (Sweden)

    Michael S. Stone

    2016-07-01

    Full Text Available Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+ ATPase pump. Approximately 90% of potassium consumed (60–100 mEq is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN is the leading cause of cardiovascular disease (CVD and a major financial burden ($50.6 billion to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health.

  14. Potassium Intake, Bioavailability, Hypertension, and Glucose Control

    Science.gov (United States)

    Stone, Michael S.; Martyn, Lisa; Weaver, Connie M.

    2016-01-01

    Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+) ATPase pump. Approximately 90% of potassium consumed (60–100 mEq) is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN) is the leading cause of cardiovascular disease (CVD) and a major financial burden ($50.6 billion) to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics) may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health. PMID:27455317

  15. [Prevalence of anemia, calcium-phosphorus abnormalities and metabolic acidosis in different stages of chronic renal failure].

    Science.gov (United States)

    Zarzecki, Miłosz; Chudek, Jerzy; Kukla, Małgorzata; Kopeć, Paulina; Mamcarz, Ewelina; Wnuk, Zuzanna; Kokot, Franciszek; Wiecek, Andrzej

    2004-10-01

    Chronic kidney disease (CKD) is associated with the reduction of haemoglobin concentration and a variety of biochemical abnormalities including changes in serum concentration of sodium, potassium, calcium, phosphate, bicarbonate, and hydrogen ions. However, data concerning epidemiology of these abnormalities are rare and incomplete, especially among subjects with mild to moderate CKD. Patients with a serum creatinine concentration > 110 micromol/l hospitalized in the Department of Nephrology, Endocrinology and Metabolic Diseases Medical University of Silesia from 1998 to 2002 were analyzed. Patients with acute renal failure or chronic renal failure treated with renal replacement therapy were excluded from this study. A total of 653 patients (262F and 391M) were divided into 9 subgroups differing from each other by progressive decline of glomerular filtration rate (GFR). A statistically significant decrease in haemoglobin concentration and increase in the prevalence of anaemia were found in patients with GFR 50 ml/min, Hb concentration 4.44 mmol2/12) was noticed almost exclusively in patients with GFR< 30 ml/min. A decompensated metabolic acidosis was observed in 29.8% of patients with GFR <30 ml/min. Anaemia is an early symptom of chronic kidney disease preceding disturbances of calcium, phosphate and hydrogen ions metabolism. These abnormalities seem to be of therapeutic relevance.

  16. Absence of Non-Bridging Oxygen on the Metaluminous Join in Potassium Aluminosilicate Glasses

    Science.gov (United States)

    Thompson, L. M.; Stebbins, J. F.

    2009-12-01

    In aluminosilicate melts and glasses, non-bridging oxygen (NBO) have a significant influence on thermodynamic and transport properties such as configurational entropy and viscosity. However, both its role and the extent of its influence are not yet fully understood, particularly in metaluminous and peraluminous compositions. Viscosity measurements from sodium, calcium, and magnesium aluminosilicate melts first suggested the presence of NBO on the metaluminous join (e.g. CaAl2O4-SiO2) (Toplis et al., 1996, 2004); direct observation with 17O nuclear magnetic resonance (NMR) spectroscopy has so far been limited to calcium aluminosilicate glasses, where it has been observed in both metalumious and peraluminous compositions (Stebbins et al., 2008). Potassium aluminosilicate glasses are another candidate for exploring the possibility of NBO on the metaluminous join, as the NBO peak is partially resolved from the bridging oxygen peak even in the one dimensional magic angle spinning (MAS) spectrum. However, preliminary analysis of 17O NMR spectra of slightly peraluminous potassium aluminosilicate glasses shows no detectable signal (<1% of total oxygen) in the area expected for NBO. Calcium aluminosilicate glasses of similar compositions have an NBO content of approximately 4.5%. This comparison shows an influence by the field strength of the network modifying cation on the presence of NBO and fraction of five-coordinated aluminum at the glass transition. However, understanding the extent of this impact in melts requires additional work exploring the temperature effects on speciation in the potassium aluminosilicate glasses.

  17. Calcium Absorption in Infants and Small Children: Methods of Determination and Recent Findings

    Directory of Open Access Journals (Sweden)

    Steven A. Abrams

    2010-04-01

    Full Text Available Determining calcium bioavailability is important in establishing dietary calcium requirements. In infants and small children, previously conducted mass balance studies have largely been replaced by stable isotope-based studies. The ability to assess calcium absorption using a relatively short 24-hour urine collection without the need for multiple blood samples or fecal collections is a major advantage to this technique. The results of these studies have demonstrated relatively small differences in calcium absorption efficiency between human milk and currently available cow milk-based infant formulas. In older children with a calcium intake typical of Western diets, calcium absorption is adequate to meet bone mineral accretion requirements.

  18. 低强度自主神经节刺激对犬心房离子电流的影响%Effects of 6 hours low level ganglionated plexi stimulation on canine atrial acetylcholine-regulated potassium current and L-type calcium current

    Institute of Scientific and Technical Information of China (English)

    黄兵; 鲁志兵; 吴柳; 何勃; 何文博; 崔博; 胡笑容; 江洪

    2012-01-01

    目的 研究6h低强度自主神经节(GP)刺激对犬乙酰胆碱依赖性钾电流(IKACh)和L型钙电流(ICaL)的影响.方法 22只成年杂种犬随机分为2组:实验组16只,对左上GP及右前GP予以6h低强度高频刺激;对照组6只,在心房远离GP处同样予以6h低强度刺激.刺激结束后分别用膜片钳、实时定量反转录-聚合酶链反应( RT-PCR)和蛋白免疫印迹(Western Blot)技术检测右心房(RA)、左心房(LA)及左上肺静脉(LSPV)处组织IKACh和ICaL密度,以及相应通道亚单位Kir 3.4和CaV 1.2的mRNA水平和蛋白含量水平.结果 与对照组相比,6h低强度高频刺激可以导致:①LSPV处IKACh电流密度[ (9.8±0.6) pA/pF对(7.9±0.3)pA/pF,P<0.01]和相应的通道亚单位Kir 3.4蛋白水平(3.3±0.5对1.6±0.1,P<0.001)显著增加;②RA、LA及LSPV处ICaL电流密度[RA:(2.0±0.2) pA/pF对(2.8±0.2) pA/pF,P<0.01;LA:(2.3±0.3) pA/pF对(5.0±0.3) pA/pF,P<0.001; LSPV:(2.5±0.2) pA/pF对(4.3±0.4)pA/pF,P<0.01]和相应的通道亚单位CaV 1.2蛋白水平(RA:0.8±0.1对1.1±0.1,P<0.01;LA:1.1±0.1对1.7±0.2,P<0.01;LSPV:0.5±0.1对0.8±0.1,P<0.001)显著下降;③Kir 3.4(RA:0.9±0.1对0.8±0.1,P>0.05;LA:1.0±0.1对0.9±0.1,P>0.05;LSPV:1.1±0.1对1.1 ±0.0,P>0.05)和CaV 1.2(RA:0.9±0.1对1.0±0.1,P>0.05;LA:0.8±0.1对0.9±0.1,P>0.05;LSPV:1.1±0.1对1.1±0.1,P>0.05)的mRNA水平差异无统计学意义.结论 6h低强度GP刺激可以通过转录后调节引起IKACh电流密度增加和ICaL电流密度的下降.%Objective To investigate the effects of 6 hours low level ganglionated plexi(GP) stimulation (LL-GPS) on canine atrial acetylcholine- regulated potassium current(IKACh ) and L-type calcium current( ICaL ).Methods In twenty-two anesthetized open-chest dogs,electrodes on the anterior right GP(ARGP) and superior left GP(SLGP) allowed 6 hours low level GP stimulation(0.1-1.0V)in 16 dogs and the similar low-level stimulation( without myocardial capture

  19. Safety assessment of Salicylic Acid, Butyloctyl Salicylate, Calcium Salicylate, C12-15 Alkyl Salicylate, Capryloyl Salicylic Acid, Hexyldodecyl Salicylate, Isocetyl Salicylate, Isodecyl Salicylate, Magnesium Salicylate, MEA-Salicylate, Ethylhexyl Salicylate, Potassium Salicylate, Methyl Salicylate, Myristyl Salicylate, Sodium Salicylate, TEA-Salicylate, and Tridecyl Salicylate.

    Science.gov (United States)

    2003-01-01

    Salicylic Acid is an aromatic acid used in cosmetic formulations as a denaturant, hair-conditioning agent, and skin-conditioning agent--miscellaneous in a wide range of cosmetic products at concentrations ranging from 0.0008% to 3%. The Calcium, Magnesium, and MEA salts are preservatives, and Potassium Salicylate is a cosmetic biocide and preservative, not currently in use. Sodium Salicylate is used as a denaturant and preservative (0.09% to 2%). The TEA salt of Salicylic Acid is used as an ultraviolet (UV) light absorber (0.0001% to 0.75%). Several Salicylic Acid esters are used as skin conditioning agents--miscellaneous (Capryloyl, 0.1% to 1%; C12-15 Alkyl, no current use; Isocetyl, 3% to 5%; Isodecyl, no current use; and Tridecyl, no current use). Butyloctyl Salicylate (0.5% to 5%) and Hexyldodecyl Salicylate (no current use) are hair-conditioning agents and skin-conditioning agents--miscellaneous. Ethylhexyl Salicylate (formerly known as Octyl Salicylate) is used as a fragrance ingredient, sunscreen agent, and UV light absorber (0.001% to 8%), and Methyl Salicylate is used as a denaturant and flavoring agent (0.0001% to 0.6%). Myristyl Salicylate has no reported function. Isodecyl Salicylate is used in three formulations, but no concentration of use information was reported. Salicylates are absorbed percutaneously. Around 10% of applied salicylates can remain in the skin. Salicylic Acid is reported to enhance percutaneous penetration of some agents (e.g., vitamin A), but not others (e.g., hydrocortisone). Little acute toxicity (LD(50) in rats; >2 g/kg) via a dermal exposure route is seen for Salicylic Acid, Methyl Salicylate, Tridecyl Salicylate, and Butyloctyl Salicylate. Short-term oral, inhalation, and parenteral exposures to salicylates sufficient to produce high blood concentrations are associated primarily with liver and kidney damage. Subchronic dermal exposures to undiluted Methyl Salicylate were associated with kidney damage. Chronic oral exposure to

  20. Effect of calcium on the physical properties of stirred probiotic yogurt.

    Science.gov (United States)

    Ramasubramanian, L; Restuccia, C; Deeth, H C

    2008-11-01

    The effect of calcium on the viscosity, firmness, and smoothness, as determined by extent of nodulation, of stirred probiotic yogurt produced by bacterial fermentation was investigated. Standardized milk for yogurt manufacture was prepared, and calcium was added or removed from the system. Calcium was added as Ca(2+) in the form of CaCl(2) (up to 13.6 mM) or nonionic calcium as Gadocal-K (calcium potassium citrate; up to 49.8 mM). Calcium was removed by chelating with sodium citrate (up to 16 mM) or by cation exchange with Amberlite IR-120 plus (sodium form) resin (up to 10 g/L). Calcium chloride and sodium citrate were added either before or after heat treatment of milk, and nonionic calcium was added before heat treatment. Calcium removal by ion exchange was performed before heat treatment. Neither Ca(2+) addition nor removal by chelation with citrate resulted in stirred yogurt with viscosity, firmness, and smoothness superior to those of the control yogurt, whereas addition of 49.8 mM nonionic calcium and removal of calcium (5.6 mM or ~10% of total calcium) by cation exchange improved the firmness and viscosity without affecting yogurt smoothness. The study identified Gadocal-K as a possible source of calcium fortification of stirred yogurt without loss of texture.

  1. Replacing a Missing Tooth

    Science.gov (United States)

    ... vessels in the tooth pulps are rather large. Drilling down these teeth for crowns may expose the ... porcelain replacement tooth is held in place by metal extensions cemented to the backs of the adjacent ...

  2. Hormone Replacement Therapy

    Science.gov (United States)

    ... before and during menopause, the levels of female hormones can go up and down. This can cause ... hot flashes and vaginal dryness. Some women take hormone replacement therapy (HRT), also called menopausal hormone therapy, ...

  3. Knee joint replacement

    Science.gov (United States)

    ... of your kneecap. Your kneecap is called the patella. The replacement part is usually made from a ... long. Then your surgeon will: Move your kneecap (patella) out of the way, then cut the ends ...

  4. Knee joint replacement - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100088.htm Knee joint replacement - series—Normal anatomy To use the ... to slide 4 out of 4 Overview The knee is a complex joint. It contains the distal ...

  5. Product Platform Replacements

    DEFF Research Database (Denmark)

    Sköld, Martin; Karlsson, Christer

    2012-01-01

    Purpose – It is argued in this article that too little is known about product platforms and how to deal with them from a manager's point of view. Specifically, little information exists regarding when old established platforms are replaced by new generations in R&D and production environments...... originality and value is achieved by focusing on product platform replacements believed to represent a growing management challenge....

  6. Physicochemical properties of calcium polycarbophil, a water-absorbing polymer.

    Science.gov (United States)

    Yamada, T; Kitayama, M; Yamazaki, M; Nagata, O; Tamaj, I; Tsuji, A

    1996-07-01

    The physicochemical properties of calcium polycarbophil were examined. Calcium polycarbophil was decalcified rapidly under acidic conditions, affording polycarbophil. Polycarbophil absorbed about 10 times its own weight of water under acidic conditions, but the swelling ratio markedly increased at above pH 4.0 and reached 70 times the initial weight under neutral conditions. The swelling of polycarbophil was not affected by non-ionic osmolarity, but was affected by ionic strength, showing a decrease with increase of ionic strength. Monovalent metal ions such as sodium and potassium ions in gastrointestinal fluid did not reduce the equilibrium swelling of polycarbophil, but divalent ions such as calcium and magnesium ions did. However, calcium ion only slightly reduced the equilibrium swelling under sodium-rich conditions. The viscosity (as an indicator of fluidity) of polycarbophil was larger than that of CMC-Na at every shear rate and polymer content examined.

  7. [The character of calcium distribution in developing anther of lettuce (Lactuca sativa L.)].

    Science.gov (United States)

    Qiu, Yi Lan; Liu, Ru Shi; Xie, Chao Tian; Yang, Yan Hong; Xu, Qing; Tian, Hui Qiao

    2005-10-01

    Potassium antimonite was used to locate calcium in the anther of lettuce (Lactuca sativa L) during its development. At the early stage of anther development there were few calcium granules in microspore mother cells and the cells of anther wall. After meiosis of microspore mother cells, calcium granules first appeared in the tapetal cells in which some small secretive vacuoles containing many calcium granules were formed and secreted into locule. Then, the tapetal cells began to degenerate. At the late stage of microspore, tapetal cells completely degenerated and its protoplast masses moved into anther locule with many calcium granules. Few calcium granules were precipitated in the microspores just being released from tetrad, but some on the surface of exine. Then calcium granules appeared in the nucleus and cytoplasm of early microspores, as wall as in the exine. When microspores formed some small vacuoles containing some calcium granules, and then the small vacuoles fused to form a large vacuole, the calcium granules in the nucleus and cytoplasm evidently decreased, microspore developed to the late stage. The result suggested that calcium is related to the formation of large vacuole in microspores. The wall of microspore also is a main location of calcium granules during its developing. At early microspore some calcium granules began to accumulate in exine, which suggested calcium related with exine formation. At late stage of microspore, most of calcium granules were mainly deposited on the surface of exine. After the first mitosis of microspores, the large vacuole of bicellular pollen disappeared and calcium granules in the large vacuole went back to cytoplasm again. When bicellular pollen synthesized starches some calcium granules appeared on the surface of starches, which suggested calcium may regulate starch synthesis. With amount of starches increasing, calcium granules disappeared from pollen cytoplasm and only some of them located on the surface of pollen.

  8. 21 CFR 184.1625 - Potassium citrate.

    Science.gov (United States)

    2010-04-01

    ... is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium citrate. 184.1625 Section 184.1625 Food... Specific Substances Affirmed as GRAS § 184.1625 Potassium citrate. (a) Potassium citrate (C6H5K3O7·H2O,...

  9. [Rare, severe hypersensitivity reaction to potassium iodide].

    Science.gov (United States)

    Korsholm, Anne Sofie; Ebbehøj, Eva; Richelsen, Bjørn

    2014-07-07

    The literature reports a large variety of adverse reactions to potassium iodide. A severe hypersensitivity reaction to potassium iodide in a 51-year-old woman with Graves' thyrotoxicosis is described. Following administration the patient developed sialadenitis, conjunctivitis, stomatitis and acneiform iododerma that responded dramatically to withdrawal of the potassium iodide and administration with corticosteroids. Awareness of these adverse reactions may prevent prolonged hospitalization and unnecessary tests and treatments.

  10. Inward-rectifying potassium channelopathies: new insights into disorders of sodium and potassium homeostasis.

    Science.gov (United States)

    Cheng, Chih-Jen; Sung, Chih-Chien; Huang, Chou-Long; Lin, Shih-Hua

    2015-03-01

    Inward-rectifying potassium (Kir) channels allow more inward than outward potassium flux when channels are open in mammalian cells. At physiological resting membrane potentials, however, they predominantly mediate outward potassium flux and play important roles in regulating the resting membrane potential in diverse cell types and potassium secretion in the kidneys. Mutations of Kir channels cause human hereditary diseases collectively called Kir channelopathies, many of which are characterized by disorders of sodium and potassium homeostasis. Studies on these genetic Kir channelopathies have shed light on novel pathophysiological mechanisms, including renal sodium and potassium handling, potassium shifting in skeletal muscles, and aldosterone production in the adrenal glands. Here, we review several recent advances in Kir channels and their clinical implications in sodium and potassium homeostasis.

  11. Genetic Control of Potassium Channels.

    Science.gov (United States)

    Amin, Ahmad S; Wilde, Arthur A M

    2016-06-01

    Approximately 80 genes in the human genome code for pore-forming subunits of potassium (K(+)) channels. Rare variants (mutations) in K(+) channel-encoding genes may cause heritable arrhythmia syndromes. Not all rare variants in K(+) channel-encoding genes are necessarily disease-causing mutations. Common variants in K(+) channel-encoding genes are increasingly recognized as modifiers of phenotype in heritable arrhythmia syndromes and in the general population. Although difficult, distinguishing pathogenic variants from benign variants is of utmost importance to avoid false designations of genetic variants as disease-causing mutations.

  12. Sodium and Potassium Currents Influence Wallerian Degeneration of Injured Drosophila Axons

    Science.gov (United States)

    Mishra, Bibhudatta; Carson, Ross; Hume, Richard I.

    2013-01-01

    Axons degenerate after injury and in neuropathies and disease via a self-destruction program whose mechanism is poorly understood. Axons that have lost connection to their cell bodies have altered electrical and synaptic activities, but whether such changes play a role in the axonal degeneration process is not clear. We have used a Drosophila model to study the Wallerian degeneration of motoneuron axons and their neuromuscular junction synapses. We found that degeneration of the distal nerve stump after a nerve crush is greatly delayed when there is increased potassium channel activity (by overexpression of two different potassium channels, Kir2.1 and dORKΔ-C) or decreased voltage-gated sodium channel activity (using mutations in the para sodium channel). Conversely, degeneration is accelerated when potassium channel activity is decreased (by expressing a dominant-negative mutation of Shaker). Despite the effect of altering voltage-gated sodium and potassium channel activity, recordings made after nerve crush demonstrated that the distal stump does not fire action potentials. Rather, a variety of lines of evidence suggest that the sodium and potassium channels manifest their effects upon degeneration through changes in the resting membrane potential, which in turn regulates the level of intracellular free calcium within the isolated distal axon. PMID:24285879

  13. Copper, aluminum, iron and calcium inhibit human acetylcholinesterase in vitro.

    Science.gov (United States)

    Pohanka, Miroslav

    2014-01-01

    Acetylcholinesterase (AChE) is an important part of cholinergic nerves where it participates in termination of neurotransmission. AChE can be inhibited by e.g. some Alzheimer disease drugs, nerve agents, and secondary metabolites. In this work, metal salts aluminum chloride, calcium chloride, cupric chloride, ferric chloride, potassium chloride, magnesium chloride and sodium chloride were tested for their ability to inhibit AChE. Standard Ellman assay based on human recombinant AChE was done and inhibition was measured using Dixon plot. No inhibition was proved for sodium, potassium and magnesium ions. However, aluminum, cupric, ferric and calcium ions were able to inhibit AChE via noncompetitive mechanism of inhibition. Though the inhibition is much weaker when compared to e.g. drugs with noncompetitive mechanism of action, biological relevance of the findings can be anticipated.

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

    DEFF Research Database (Denmark)

    Knudsen, T; Johansen, Torben

    1989-01-01

    1 The inhibition by calcium of the Na(+)-K+ pump in the plasma membrane of rat peritoneal mast cells was studied in pure populations of the cells by measuring the ouabain-sensitive uptake of the radioactive potassium analogue, 86rubidium (86Rb+). 2 Exposure of the cells to calcium induced a time...... not develop when the mast cells were incubated in a potassium-free medium, which is known to block Na(+)-K+ pump activity and allow accumulation of sodium inside the cells. Likewise, increasing the sodium permeability of the plasma membrane by monensin abolished the inhibition of the pump activity. In both...... peritoneal mast cells in a calcium-free medium increases the permeability of the plasma membrane to sodium, and the consequent increase in the intracellular concentration of sodium causes an increase in the activity of the pump. Addition of calcium to the cell suspension decreases the sodium permeability...

  15. T-type voltage-gated calcium channels regulate the tone of mouse efferent arterioles

    DEFF Research Database (Denmark)

    Poulsen, Christian B; Al-Mashhadi, Rozh H; Cribbs, Leanne L;

    2011-01-01

    Voltage-gated calcium channels are important for the regulation of renal blood flow and the glomerular filtration rate. Excitation-contraction coupling in afferent arterioles is known to require activation of these channels and we studied their role in the regulation of cortical efferent arteriolar...... tone. We used microdissected perfused mouse efferent arterioles and found a transient vasoconstriction in response to depolarization with potassium; an effect abolished by removal of extracellular calcium. The T-type voltage-gated calcium channel antagonists mibefradil and nickel blocked this potassium....... Low concentrations of nickel, an agent that blocks Ca(v)3.2, had a similar effect. Thus, T-type voltage-gated calcium channels are functionally important for depolarization-induced vasoconstriction and subsequent dilatation in mouse cortical efferent arterioles.Kidney International advance online...

  16. [The dynamic of calcium distribution during megasporegenesis of lettuce (Lactuca sativa L.)].

    Science.gov (United States)

    Qiu, Yi-Lan; Liu, Ru-Shi; Xie, Chao-Tian; Yang, Yan-Hong; Ge, Li-Li; Tian, Hui-Qiao

    2005-08-01

    Potassium antimonite was used to deposit calcium in the young ovule of lettuce (Lactuca sativa L.) at megasporogenesis stage to study the relationship between calcium and megaspore degeneration. At the megaspore mother cell stage, few calcium granules were formed in the cell (Plate I-1, 2). After meiosis of megaspore mother cell and forming an arrayed tetrad in a line (Plate I-3), three megaspores degenerated one by one from the micropyle end. In the process of degeneration, the numbers of calcium granules decreased in the three megaspores. After the first megaspore degenerated, the number of calcium granules decreased in the second megaspore, which began to degenerate (Plate II-7, 8). The third megaspore also had its number of calcium granules diminishing before it degenerated (Plate III-13, 14). The fourth megaspore always accumulated many calcium granules in the cytoplasm during its development (Plate IV-17, 18) and finally becomes functional one that will develop into an embryo sac (Plate IV-20). Megaspore degeneration is a process of programmed cell death which may be closely related with change in calcium content: when a megaspore of tetrad decreases calcium content the cell begins to degenerate, and when calcium increases in the cell, it will continue to develop into a functional megaspore. This is the first report about calcium distribution in megaspores of a tetrad during megasporogenesis in higher plants and will open a door to study the physiological function of calcium in megasporogenesis.

  17. Calcium Solubility and Cation Exchange Properties in Zeoponic Soil

    Science.gov (United States)

    Beiersdorfer, Raymond E.

    1999-01-01

    An important aspect of a regenerative life support system at a Lunar or Martian outpost is the ability to produce food. Essential plant nutrients, as well as a solid support substrate, can be provided by: (1) treated Lunar or Martian regolith; (2) a synthetic soil or (3) some combination of both. A synthetic soil composed of ammonium- and potassium-saturated chinoptlolite (a zeolite mineral) and apatite, can provide slow-release fertilization of plants via dissolution and ion-exchange reactions. Previous equilibrium studies (Beiersdorfer, 1997) on mixtures of synthetic hydroxyapatite and saturated-clinoptilolite indicate that the concentrations of macro-nutrients such as ammonium, phosphorous, potassium, magnesium, and calcium are a function of the ratio of chinoptilolite to apatite in the sample and to the ratio of potassium to ammonium on the exchange sites in the clinoptilolite. Potassium, ammonium, phosphorous, and magnesium are available to plants at sufficient levels. However, calcium is deficient, due to the high degree of calcium adsorption by the clinoptilolite. Based on a series of batch-equilibration experiments, this calcium deficiency can be reduced by (1) treating the clinoptilolite with CaNO3 or (2) adding a second Ca-bearing mineral (calcite, dolomite or wollastonite) to the soil. Treating the Cp with CaNO3 results in increased Ca in solution, decreased P in solution and decreased NH4 in solution. Concentrations of K were not effected by the CaNO3 treatment. Additions of Cal, Dol and Wol changed the concentrations of Ca and P in solution in a systematic fashion. Cal has the greatest effect, Dol the least and Wol is intermediate. The changes are consistent with changes expected for a common ion effect with Ca. Higher concentrations of Ca in solution with added Cal, Dol or Wol do not result in changes in K or NH4 concentrations.

  18. How far can sodium substitute for potassium in red beet?

    Science.gov (United States)

    Subbarao, G. V.; Wheeler, R. M.; Stutte, G. W.; Levine, L. H.; Sager, J. C. (Principal Investigator)

    1999-01-01

    Sodium (Na) movement between plants and humans is one of the more critical aspects of bioregenerative systems of life support, which NASA is studying for the establishment of long-term bases on the Lunar or Martian surface. This study was conducted to determine the extent to which Na can replace potassium (K) in red beet (Beta vulgaris L. ssp vulgaris) without adversely affecting metabolic functions such as water relations, photosynthetic rates, and thus growth. Two cultivars, Ruby Queen and Klein Bol, were grown for 42 days at 1200 micromoles mol-1 CO2 in a growth chamber using a re-circulating nutrient film technique with 0%, 75%, 95%, and 98% Na substitution for K in a modified half-strength Hoagland solution. Total biomass of Ruby Queen was greatest at 95% Na substitution and equal at 0% and 98% Na substitution. For Klein Bol, there was a 75% reduction in total biomass at 98% Na substitution. Nearly 95% of the total plant K was replaced with Na at 98% Na substitution in both cultivars. Potassium concentrations in leaves decreased from 120 g kg-1 dwt in 0% Na substitution to 3.5 g kg-1 dwt at 98% Na substitution. Leaf chlorophyll concentration, photosynthetic rate, and osmotic potential were not affected in either cultivar by Na substitution for K. Leaf glycinebetaine levels were doubled at 75% Na substitution in Klein Bol, but decreased at higher levels of Na substitution. For Ruby Queen, glycinebetaine levels in leaf increased with the first increase of Na levels and were maintained at the higher Na levels. These results indicate that in some cultivars of red beet, 95% of the normal tissue K can be replaced by Na without a reduction in growth.

  19. 不同形态钾肥在油菜上的施用效果%Effect of Different Forms of Potassium Fertilizer Applied on Oilseed Rape

    Institute of Scientific and Technical Information of China (English)

    张丽; 张洋洋; 薛欣欣; 任涛; 鲁剑巍; 吕忠群

    2012-01-01

    The effects of three different forms of potassium fertilizers (water-soluble potassium, citrate acid-soluble potassium and mineral potassium fertilizer) on oilseed rape were studied using pots experiment. Under the same nutrient input, the mineral potassium fertilizer (potassium feldspar) had no effect on oilseed rape, while the water-soluble potassium (potassium sulfate) and citrate acid-soluble potassium (Potassium-Silicon mineral fertilizer) could significantly improve the biomass, potassium content and potassium accumulation of oilseed rape and potassium fertilizer utilization efficiency. Compared with the contrast treatment (without potassium fertilization), water-soluble potassium and citrate acid-soluble potassium increased 37.7% and 47.6% of the rape biomass, and 2.05 and 2.14 times of aboveground potassium accumulation respectively. The potassium fertilizer utilization efficiency of water-soluble potassium and citrate acid-soluble potassium was 29.6% and 31.2% respectively. The results showed that in potassium deficiency conditions, the water soluble potassium and citrate soluble state potassium could effectively provide potassium nutrient for crop; and the effect of citrate soluble state potassium was better than that of the water soluble potassium, indicating that citrate acid-soluble potassium could replace water-soluble potassium.%采用盆栽试验方法,研究了水溶态、枸溶态和矿物态3种不同形态钾肥的施用效果.结果表明,在等养分投入条件下,矿物态钾肥(钾长石)对油菜生物量和钾素吸收没有效果,而水溶态钾肥(硫酸钾)和枸溶态钾肥(钾硅肥)均显著提高油菜生物量、钾素含量和钾素积累量.与对照不施钾肥相比,水溶态钾肥和枸溶态钾肥分别提高油菜生物量37.7%和47.6%,分别增加地上部钾素累积量2.05倍和2.14倍,钾肥利用率分别为29.6%和31.2%.在缺钾条件下,水溶态钾肥和枸溶态钾肥均能有效为油菜提供钾素养

  20. Nonequilibrium Calcium Dynamics Regulate the Autonomous Firing Pattern of Rat Striatal Cholinergic Interneurons

    OpenAIRE

    Goldberg, Joshua A.; Teagarden, Mark A.; Foehring, Robert C.; Wilson, Charles J.

    2009-01-01

    Striatal cholinergic interneurons discharge rhythmically in two patterns associated with different afterhyperpolarization timescales, each dictated by a different calcium-dependent potassium current. Single spiking depends on a medium-duration afterhyperpolarization (mAHP) generated by rapid SK currents that are associated with N-type calcium channels. Periodic bursting is driven by a delayed and slowly decaying afterhyperpolarization (sAHP) current associated with L-type channels. Using calc...

  1. Formulation, Characterization and Physicochemical Evaluation of Potassium Citrate Effervescent Tablets

    Directory of Open Access Journals (Sweden)

    Fatemeh Fattahi

    2013-02-01

    Full Text Available Purpose: The aim of this study was to design and formulation of potassium citrate effervescent tablet for reduction of calcium oxalate and urate kidney stones in patients suffering from kidney stones. Methods: In this study, 13 formulations were prepared from potassium citrate and effervescent base in different concentration. The flowability of powders and granules was studied. Then effervescent tablets were prepared by direct compression, fusion and wet granulation methods. The prepared tablets were evaluated for hardness, friability, effervescent time, pH, content uniformity. To amend taste of formulations, different flavoring agents were used and then panel test was done by using Latin Square method by 30 volunteers. Results: Formulations obtained from direct compression and fusion methods had good flow but low hardness. Wet granulation improves flowability and other physicochemical properties such as acceptable hardness, effervescence time ≤3 minutes, pH<6, friability < 1%, water percentage < 0.5% and accurate content uniformity. In panel test, both of combination flavors; (orange - lemon and (strawberry - raspberry had good acceptability. Conclusion: The prepared tablets by wet granulation method using PVP solution had more tablet hardness. It is a reproducible process and suitable to produce granules that are compressed into effervescent tablets due to larger agglomerates.

  2. Integumentary loss of calcium.

    Science.gov (United States)

    Chu, J Y; Margen, S; Calloway, D H; Costa, F M

    1979-08-01

    Integumentary calcium loss was studied in 16 healthy young men. The daily loss by the 16 ambulatory but relatively sedentary young men in 52 determinations of 6-day periods each was 8.7 +/- 1.9 mg/m2 per day (average 15.8 mg/man per day). The amount lost was not influenced by calcium intake (0.1 to 2.3 g/day). In contrast to urinary calcium excretion, which is directly related to protein intake, there was no significant change in integumentary calcium loss with varying protein intakes (1 to 96 g nitrogen per day). No compensatory relationship between urinary and integumentary calcium excretion was noted. During strenuous exercise calcium loss increased to an average of 25 mg in 40 min. There was no compensatory decrease in urinary excretion on the day of strenuous exercise. It was also noted that integumentary calcium loss was not affected by general calcium balance.

  3. 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.

  4. 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.

  5. METHODS OF AVAILABLE POTASSIUM ASSESSMENT IN ...

    African Journals Online (AJOL)

    AGROSEARCH UIL

    Soil potassium (K+) exists in solution, exchangeable, and non-exchangeable ... evaluating K availability under intensive cropping; as those soils considered sufficient in ... response to potassium, soil test methods should have a high correlation with .... loamy sand to sandy loam in texture with kaolinite being the dominant.

  6. Thanatochemistry: Study of synovial fluid potassium

    African Journals Online (AJOL)

    Nilesh Keshav Tumram

    2014-03-28

    Mar 28, 2014 ... sion equations, but these may be useless when dealing with eye trauma, ocular disorders or in muti- lated remains. .... potassium concentration which rises more rapidly in the first .... postmortem interval based on differential behaviour of vitreous ... course of potassium ion activity in cadaveric synovial fluid.

  7. Extraction of potassium from K-feldspar via the CaCl2 calcination route☆

    Institute of Scientific and Technical Information of China (English)

    Bo Yuan; Chun Li; Bin Liang; Li Lü; Hairong Yue; Haoyi Sheng; Longpo Ye; Heping Xie

    2015-01-01

    The extraction of potassium from K-feldspar via a calcium chloride calcination route was studied with a focus on the effects of the calcination atmosphere, calcination temperature and time, mass ratio of CaCl2 to K-feldspar ore and particle size of the K-feldspar ore. The results demonstrated that a competing high-temperature hydrolysis reaction of calcium chloride with moisture in a damp atmosphere occurred concurrently with the conversion reaction of K-feldspar with CaCl2, thus reducing the amount of potassium extracted. The conversion reaction started at approximately 600 °C and accelerated with increasing temperature. When the temperature rose above 900 °C, the extraction of potassium gradually decreased due to the volatilization of the product, KCl. As much as approximately 41%of the potassium was volatilized in 40 min at 1100 °C. The mass ratio of CaCl2/K-feldspar ore significantly affected the extraction. At a mass ratio of 1.15 and 900 °C, the potassium extraction reached 91%in 40 min, while the extraction was reduced to only 22%at the theoretical mass ratio of 0.2. Optimal process conditions are as follows:ore particle size of 50–75μm, tablet forming pressure of 3 MPa, dry nitrogen atmosphere, mass ratio of CaCl2/ore 1.15:1, calcination temperature of 900 °C, and calcination time of 40 min. The XRD analysis revealed that a complex phase transition of the product SiO2 was also accompanied by the con-version reaction of K-feldspar/CaCl2. The SiO2 product formed at the initial stage was in the quartz phase at 900 °C and was gradually transformed into cristobalite after 30 min.

  8. Calcium - Function and effects

    NARCIS (Netherlands)

    Liang, Jianfen; He, Yifan; Gao, Qian; Wang, Xuan; Nout, M.J.R.

    2016-01-01

    Rice is the primary food source for more than half of the world population. Levels of calcium contents and inhibitor - phytic acid are summarized in this chapter. Phytic acid has a very strong chelating ability and it is the main inhibit factor for calcium in rice products. Calcium contents in br

  9. Calcium en cardioplegie

    NARCIS (Netherlands)

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

    1985-01-01

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

  10. Potassium in hypertension and cardiovascular disease.

    Science.gov (United States)

    Castro, Hector; Raij, Leopoldo

    2013-05-01

    The increased prevalence of hypertension and cardiovascular disease in industrialized societies undoubtedly is associated with the modern high-sodium/low-potassium diet. Extensive experimental and clinical data strongly link potassium intake to cardiovascular outcome. Most studies suggest that the sodium-to-potassium intake ratio is a better predictor of cardiovascular outcome than either nutrient individually. A high-sodium/low-potassium environment results in significant abnormalities in central hemodynamics, leading to potential target organ damage. Altered renal sodium handling, impaired endothelium-dependent vasodilatation, and increased oxidative stress are important mediators of this effect. It remains of paramount importance to reinforce consumption of a low-sodium/high-potassium diet as a critical strategy for prevention and treatment of hypertension and cardiovascular disease.

  11. Extracellular potassium inhibits Kv7.1 potassium channels by stabilizing an inactivated state

    DEFF Research Database (Denmark)

    Larsen, Anders Peter; Steffensen, Annette Buur; Grunnet, Morten;

    2011-01-01

    Kv7.1 (KCNQ1) channels are regulators of several physiological processes including vasodilatation, repolarization of cardiomyocytes, and control of secretory processes. A number of Kv7.1 pore mutants are sensitive to extracellular potassium. We hypothesized that extracellular potassium also...... modulates wild-type Kv7.1 channels. The Kv7.1 currents were measured in Xenopus laevis oocytes at different concentrations of extracellular potassium (1-50 mM). As extracellular potassium was elevated, Kv7.1 currents were reduced significantly more than expected from theoretical calculations based...... on the Goldman-Hodgkin-Katz flux equation. Potassium inhibited the steady-state current with an IC(50) of 6.0 ± 0.2 mM. Analysis of tail-currents showed that potassium increased the fraction of channels in the inactivated state. Similarly, the recovery from inactivation was slowed by potassium, suggesting...

  12. Robotic mitral valve replacement.

    Science.gov (United States)

    Senay, Sahin; Gullu, Ahmet Umit; Kocyigit, Muharrem; Degirmencioglu, Aleks; Karabulut, Hasan; Alhan, Cem

    2014-01-01

    Robotic surgical techniques allow surgeons to perform mitral valve surgery. This procedure has gained acceptance, particularly for mitral valve repair in degenerative mitral disease. However, mitral repair may not always be possible, especially in severely calcified mitral valve of rheumatic origin. This study demonstrates the basic concepts and technique of robotic mitral valve replacement for valve pathologies that are not suitable for repair.

  13. Replacing America's Job Bank

    Science.gov (United States)

    Vollman, Jim

    2009-01-01

    The Job Central National Labor Exchange (www.jobcentral.com) has become the effective replacement for America's Job Bank with state workforce agencies and, increasingly, with community colleges throughout the country. The American Association of Community Colleges (AACC) has formed a partnership with Job Central to promote its use throughout the…

  14. Replacing America's Job Bank

    Science.gov (United States)

    Vollman, Jim

    2009-01-01

    The Job Central National Labor Exchange (www.jobcentral.com) has become the effective replacement for America's Job Bank with state workforce agencies and, increasingly, with community colleges throughout the country. The American Association of Community Colleges (AACC) has formed a partnership with Job Central to promote its use throughout the…

  15. Impact of ingredient replacers on the physicochemical properties and sensory quality of reduced salt and fat black puddings.

    Science.gov (United States)

    Fellendorf, Susann; O'Sullivan, Maurice G; Kerry, Joseph P

    2016-03-01

    Twenty-two black puddings possessing different fat (10%, 5%) and sodium (0.6%, 0.4%) levels were used as base formulations for 11 different salt and fat replacers. Compositional, physicochemical and sensory analyses were conducted. Black pudding samples with 5% fat and 0.6% sodium containing potassium chloride (KCl), potassium chloride and glycine mixture (KClG), and seaweed, respectively, and 10% fat and 0.4% sodium containing carrageen were rated higher (Psodium containing KClG were rated positively (Psodium containing pectin and a combination of potassium citrate, potassium phosphate and potassium chloride (KCPCl), as well as samples containing 10% fat and 0.4% sodium with waxy maize starch (WMS) were liked (PFood Safety Authority of Ireland (FSAI) recommends a sodium target level of 0.6% and an even lower sodium level (0.4%) was achieved.

  16. TbIRK is a signature sequence free potassium channel from Trypanosoma brucei locating to acidocalcisomes.

    Science.gov (United States)

    Steinmann, Michael E; Schmidt, Remo S; Bütikofer, Peter; Mäser, Pascal; Sigel, Erwin

    2017-04-06

    Potassium channels from prokaryotes and eukaryotes are usually recognized by a typical amino acid sequence TXTGY(F)G representing the ionic selectivity filter. Using a screening approach with ion channel family profiles but without the above motif, we identified a gene in Trypanosoma brucei that exhibits homology to inward rectifying potassium channels. We report here cloning of this ion channel named TbIRK. The protein is localized to acidocalcisomes in procyclic and in bloodstream form parasites. Functional properties of this channel were established after expression in Xenopus oocytes. Currents recorded in potassium medium show inward rectification and little time dependence. Surprisingly, this channel retains selectivity for potassium ions over sodium ions >7, in spite of the lack of the classical selectivity filter. The sequence GGYVG was predicted in silico to replace this filter motif. Point mutations of the corresponding glycine residues confirmed this at the functional level. The channel is inhibited by caesium ions but remains unaffected by barium ions up to 10 mM. TbIRK is to our knowledge the first potassium channel in T. brucei that localizes to the acidocalcisomes, organelles involved in the storage of phosphates and the response to osmotic stress that occurs during the life cycle of trypanosomes.

  17. Calcium signaling and epilepsy.

    Science.gov (United States)

    Steinlein, Ortrud K

    2014-08-01

    Calcium signaling is involved in a multitude of physiological and pathophysiological mechanisms. Over the last decade, it has been increasingly recognized as an important factor in epileptogenesis, and it is becoming obvious that the excess synchronization of neurons that is characteristic for seizures can be linked to various calcium signaling pathways. These include immediate effects on membrane excitability by calcium influx through ion channels as well as delayed mechanisms that act through G-protein coupled pathways. Calcium signaling is able to cause hyperexcitability either by direct modulation of neuronal activity or indirectly through calcium-dependent gliotransmission. Furthermore, feedback mechanisms between mitochondrial calcium signaling and reactive oxygen species are able to cause neuronal cell death and seizures. Unravelling the complexity of calcium signaling in epileptogenesis is a daunting task, but it includes the promise to uncover formerly unknown targets for the development of new antiepileptic drugs.

  18. A mineral and antioxidant-rich extract from the red marine Algae Alsidium corallinum exhibits cytoprotective effects against potassium bromate-induced erythrocyte oxidative damages in mice.

    Science.gov (United States)

    Ben Saad, Hajer; Nasri, Imen; Elwej, Awatef; Krayem, Najeh; Jarraya, Raoudha; Kallel, Choumous; Zeghal, Najiba; Amara, Ibtissem Ben

    2014-07-01

    The present study was carried out to investigate potassium bromate toxicity in mice and the corrective effects of marine algae Alsidium corallinum. The red algae demonstrated its rich composition in phenols, triterpenes, flavonoids, alkaloids, tropolones, sodium, potassium, calcium, magnesium, iron, copper, and zinc. To confirm its antioxidant potential, an in vivo study was performed on adult mice. The animals were divided into four groups: group I were used as controls, group II received potassium bromate (0.5 g/L) via drinking water, group III received potassium bromate (0.5 g/L) by the same route as group II and 7% of A. corallinum ethanolic extract via their diet, and group IV received only 7% of algae. The potassium bromate-treated group showed a significant decrease in erythrocyte, platelet, hemoglobin, and hematocrit values and a significant increase in total white blood cells, compared to those of controls. While, superoxide dismutase, catalase, glutathione, and vitamin C values were decreased by potassium bromate treatment, lipid peroxidation (as malondialdehyde) and erythrocyte osmotic fragility values were increased. Interestingly, potassium bromate treatment showed significant genotoxic effects, as demonstrated by DNA degradation. These changes were confirmed by blood smears histopathological observations which were marked by a necrosis and a decrease of erythrocytes number. A. corallinum extract appeared to be effective against hematotoxic and genotoxic changes induced by potassium bromate, as evidenced by the improvement of the parameters cited above.

  19. Visinin-like neuronal calcium sensor proteins regulate the slow calcium-activated afterhyperpolarizing current in the rat cerebral cortex

    Science.gov (United States)

    Villalobos, Claudio; Andrade, Rodrigo

    2010-01-01

    Many neurons in the nervous systems express afterhyperpolarizations that are mediated by a slow calcium-activated potassium current. This current shapes neuronal firing and is inhibited by neuromodulators, suggesting an important role in the regulation of neuronal function. Surprisingly, very little is currently known about the molecular basis for this current or how it is gated by calcium. Recently, the neuronal calcium sensor protein hippocalcin was identified as a calcium sensor for the slow afterhyperpolarizing current in the hippocampus. However, while hippocalcin is very strongly expressed in the hippocampus, this protein shows a relatively restricted distribution in the brain. Furthermore, the genetic deletion of this protein only partly reduces the slow hyperpolarizing current in hippocampus. These considerations question whether hippocalcin can be the sole calcium sensor for the slow afterhyperpolarizing current. Here we use loss of function and overexpression strategies to show that hippocalcin functions as a calcium sensor for the slow afterhyperpolarizing current in the cerebral cortex, an area where hippocalcin is expressed at much lower levels than in hippocampus. In addition we show that neurocalcin δ, but not VILIP-2, can also act as a calcium sensor for the slow afterhyperpolarizing current. Finally we show that hippocalcin and neurocalcin δ both increase the calcium sensitivity of the afterhyperpolarizing current but do not alter its sensitivity to inhibition by carbachol acting through the Gαq-11-PLCβ signaling cascade. These results point to a general role for a subgroup of visinin-like neuronal calcium sensor proteins in the activation of the slow calcium-activated afterhyperpolarizing current. PMID:20980592

  20. VKCDB: Voltage-gated potassium channel database

    Directory of Open Access Journals (Sweden)

    Gallin Warren J

    2004-01-01

    Full Text Available Abstract Background The family of voltage-gated potassium channels comprises a functionally diverse group of membrane proteins. They help maintain and regulate the potassium ion-based component of the membrane potential and are thus central to many critical physiological processes. VKCDB (Voltage-gated potassium [K] Channel DataBase is a database of structural and functional data on these channels. It is designed as a resource for research on the molecular basis of voltage-gated potassium channel function. Description Voltage-gated potassium channel sequences were identified by using BLASTP to search GENBANK and SWISSPROT. Annotations for all voltage-gated potassium channels were selectively parsed and integrated into VKCDB. Electrophysiological and pharmacological data for the channels were collected from published journal articles. Transmembrane domain predictions by TMHMM and PHD are included for each VKCDB entry. Multiple sequence alignments of conserved domains of channels of the four Kv families and the KCNQ family are also included. Currently VKCDB contains 346 channel entries. It can be browsed and searched using a set of functionally relevant categories. Protein sequences can also be searched using a local BLAST engine. Conclusions VKCDB is a resource for comparative studies of voltage-gated potassium channels. The methods used to construct VKCDB are general; they can be used to create specialized databases for other protein families. VKCDB is accessible at http://vkcdb.biology.ualberta.ca.

  1. Potassium currents in type II vestibular hair cells isolated from the guinea-pig's crista ampullaris.

    Science.gov (United States)

    Griguer, C; Kros, C J; Sans, A; Lehouelleur, J

    1993-11-01

    Type II vestibular hair cells were isolated from cristae ampullares of guinea-pig and maintained in vitro for 2-3 h. Outward membrane currents were studied under whole-cell voltage-clamp conditions. Type II hair cells had resting potentials of about -45 mV. Depolarizing voltage steps from a holding potential of -80 or -90 mV induced time- and voltage-dependent outward currents which slowly decayed to a sustained level. Tail currents reversed at about -70 mV, indicating that the outward currents were mainly carried by potassium ions. The currents had an activation threshold around -50 mV. The transient component was completely removed by a depolarizing pre-pulse positive to -10 mV. While bath application of 4-aminopyridine (5 mM) reduced both components, extracellular tetraethylammonium (10 mM) or zero calcium preferentially diminished the sustained current. We conclude that at least two potassium conductances are present, a delayed rectifier with a relatively fast inactivation and a calcium-dependent potassium current. Depolarizing current injections induced an electrical resonance in the voltage responses, with a frequency of 25-100 Hz, larger currents causing higher frequencies.

  2. Litholytic property of Kulattha (Dolichous biflorus) vs potassium citrate in renal calculus disease: a comparative study.

    Science.gov (United States)

    Singh, Rana Gopal; Behura, Sanjeev Kumar; Kumar, Rakesh

    2010-05-01

    Renal calculus disease is associated with recurrence after its surgical removal in large number of cases. Kulattha is acclaimed to have litholytic property in ayurvedic literature. We decided to compare the litholytic property of Kulattha with potassium citrate, an agent used to reduce stone recurrence in modern medicine. Forty seven patients with diagnosis of calcium oxalate renal calculi were taken in study. Twenty four patients received Kulattha (Group I) and 23 patients were given potassium citrate(Group II) for a period of 6 months. The size of renal calculi was studied by periodic ultrasound assessment in both groups. Mean size of stone in group I at 0 month and at 6 month were 5.42 +/- 1.55 mm and 4.26 +/- 1.2 mm. mean size of stone in group II at 0 month and at 6 month was 6.46 +/- 3.08 mm and 4.64 +/- 1.40 mm. Statistical analysis showed that P value of less than 0.05 was seen in the first group from 0 to 6 month. There was no significant difference in the stone size within group II when the 3rd month and 6th month visit was compared with initial visit. Kulattha can be used to reduce the recurrence of calcium oxalate stone and it is shown to have a better result than the use of conventional potassium citrate in such patients.

  3. Ulnar head replacement.

    Science.gov (United States)

    Herbert, Timothy J; van Schoonhoven, Joerg

    2007-03-01

    Recent years have seen an increasing awareness of the anatomical and biomechanical significance of the distal radioulnar joint (DRUJ). With this has come a more critical approach to surgical management of DRUJ disorders and a realization that all forms of "excision arthroplasty" can only restore forearm rotation at the expense of forearm stability. This, in turn, has led to renewed interest in prosthetic replacement of the ulnar head, a procedure that had previously fallen into disrepute because of material failures with early implants, in particular, the Swanson silicone ulnar head replacement. In response to these early failures, a new prosthesis was developed in the early 1990s, using materials designed to withstand the loads across the DRUJ associated with normal functional use of the upper limb. Released onto the market in 1995 (Herbert ulnar head prosthesis), clinical experience during the last 10 years has shown that this prosthesis is able to restore forearm function after ulnar head excision and that the materials (ceramic head and noncemented titanium stem), even with normal use of the limb, are showing no signs of failure in the medium to long term. As experience with the use of an ulnar head prosthesis grows, so does its acceptance as a viable and attractive alternative to more traditional operations, such as the Darrach and Sauve-Kapandji procedures. This article discusses the current indications and contraindications for ulnar head replacement and details the surgical procedure, rehabilitation, and likely outcomes.

  4. Calcium channels, neuromuscular synaptic transmission and neurological diseases.

    Science.gov (United States)

    Urbano, Francisco J; Pagani, Mario R; Uchitel, Osvaldo D

    2008-09-15

    Voltage-dependent calcium channels are essential in neuronal signaling and synaptic transmission, and their functional alterations underlie numerous human disorders whether monogenic (e.g., ataxia, migraine, etc.) or autoimmune. We review recent work on Ca(V)2.1 or P/Q channelopathies, mostly using neuromuscular junction preparations, and focus specially on the functional hierarchy among the calcium channels recruited to mediate neurotransmitter release when Ca(V)2.1 channels are mutated or depleted. In either case, synaptic transmission is greatly compromised; evidently, none of the reported functional replacements with other calcium channels compensates fully.

  5. The role of calcium in health and disease.

    Science.gov (United States)

    Power, M L; Heaney, R P; Kalkwarf, H J; Pitkin, R M; Repke, J T; Tsang, R C; Schulkin, J

    1999-12-01

    Skeletal fragility at the end of the life span (osteoporosis) is a major source of morbidity and mortality. Adequate calcium intake from childhood to the end of the life span is critical for the formation and retention of a healthy skeleton. High intakes of calcium and vitamin D potentiate the bone loss prevention effects of hormone replacement therapy in postmenopausal women. Pregnancy and lactation are not risk factors for skeletal fragility, although lactation is associated with a transient loss of bone that cannot be prevented by calcium supplementation. Low calcium intake has been implicated in the development of hypertension, colon cancer, and premenstrual syndrome, and it is associated with low intakes of many other nutrients. Encouragement of increased consumption of calcium-rich foods has the potential to be a cost-effective strategy for reducing fracture incidence later in life and for increasing patients' dietary quality and overall health.

  6. Participação da excreção renal de cálcio, fósforo, sódio e potássio na homeostase em cães sadios e cães com doença renal crônica Participation of renal excretion of calcium, phosphorus, sodium and potassium on the homeostasis in healthy dogs and in dogs with chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Pedro P Martínez

    2010-10-01

    serum profile of calcium, phosphorus, sodium and potassium in healthy dogs and in dogs with naturally acquired CKD. Three groups of adult male and female dogs of varied breeds were evaluated. Normal dogs were in the control group (G1 and the CKD dogs were distributed into two groups in accordance with the stage of renal function impairment (G2 e G3, respectively, stages 1-2 and stages 3-4, proposed by IRIS 2006 staging CKD. The G3 dogs showed increased serum levels of ionized calcium and phosphorus, in addition to the reduction of sodium levels. Regarding the renal excretion of the analyzed electrolytes, the G1 and G2 groups showed a decrease of filtered load and increase of fractional excretion, yet there were no significant variations on the urinary excretions. The results suggest that the kidneys of the CKD dogs can maintain similar values of electrolytes urinary excretion as the kidneys of normal dogs. The mechanism involves an increase of fractional excretion while glomerular filtration decreases. This compensation process, however, can lose its efficiency in the later stages of the disease, in relation to the maintenance of phosphorus and sodium serum levels.

  7. Role of Ryanodine Receptor Subtypes in Initiation and Formation of Calcium Sparks in Arterial Smooth Muscle: Comparison with Striated Muscle

    Directory of Open Access Journals (Sweden)

    Maik Gollasch

    2009-01-01

    Full Text Available Calcium sparks represent local, rapid, and transient calcium release events from a cluster of ryanodine receptors (RyRs in the sarcoplasmic reticulum. In arterial smooth muscle cells (SMCs, calcium sparks activate calcium-dependent potassium channels causing decrease in the global intracellular [Ca2+] and oppose vasoconstriction. This is in contrast to cardiac and skeletal muscle, where spatial and temporal summation of calcium sparks leads to global increases in intracellular [Ca2+] and myocyte contraction. We summarize the present data on local RyR calcium signaling in arterial SMCs in comparison to striated muscle and muscle-specific differences in coupling between L-type calcium channels and RyRs. Accordingly, arterial SMC Cav1.2 L-type channels regulate intracellular calcium stores content, which in turn modulates calcium efflux though RyRs. Downregulation of RyR2 up to a certain degree is compensated by increased SR calcium content to normalize calcium sparks. This indirect coupling between Cav1.2 and RyR in arterial SMCs is opposite to striated muscle, where triggering of calcium sparks is controlled by rapid and direct cross-talk between Cav1.1/Cav1.2 L-type channels and RyRs. We discuss the role of RyR isoforms in initiation and formation of calcium sparks in SMCs and their possible molecular binding partners and regulators, which differ compared to striated muscle.

  8. Inadvertent injection of potassium chloride instead of sodium chloride during treatment of chronic low back ache with epidural injection leading to paraplegia

    Directory of Open Access Journals (Sweden)

    Rahul Ranjan

    2016-01-01

    Full Text Available Epidural injection of steroid is given for back pain resistant to other conservative management. Normal saline (NS is used as diluent in 80 mg methylprednisolone and a local anesthetic. Due to a similar looking ampoule of NS and potassium chloride (KCl, there is a probability of accidental use of KCl instead of NS. We present a case of a 50 year old male patient having low back ache refractory to other conservative treatments. Epidural injection of steroid was given, but accidently KCl was mixed with methylprednisolone instead of NS. He developed severe cramps in the lower limbs, pruritus, and sweating, and finally paraplegia. Electrocardiography and blood showed features suggestive of hyperkalemia. He was given calcium gluconate and potassium chelating agent along with supportive measures. The patient recovered within 8 h. It is concluded that calcium gluconate and potassium chelating agent can be used if accidentally KCl is injected in epidural space.

  9. G-protein-coupled inward rectifier potassium channels involved in corticostriatal presynaptic modulation.

    Science.gov (United States)

    Meneses, David; Mateos, Verónica; Islas, Gustavo; Barral, Jaime

    2015-09-01

    Presynaptic modulation has been associated mainly with calcium channels but recent data suggests that inward rectifier potassium channels (K(IR)) also play a role. In this work we set to characterize the role of presynaptic K(IR) channels in corticostriatal synaptic transmission. We elicited synaptic potentials in striatum by stimulating cortical areas and then determined the synaptic responses of corticostriatal synapsis by using paired pulse ratio (PPR) in the presence and absence of several potassium channel blockers. Unspecific potassium channels blockers Ba(2+) and Cs(+) reduced the PPR, suggesting that these channels are presynaptically located. Further pharmacological characterization showed that application of tertiapin-Q, a specific K(IR)3 channel family blocker, also induced a reduction of PPR, suggesting that K(IR)3 channels are present at corticostriatal terminals. In contrast, exposure to Lq2, a specific K(IR)1.1 inward rectifier potassium channel, did not induce any change in PPR suggesting the absence of these channels in the presynaptic corticostriatal terminals. Our results indicate that K(IR)3 channels are functionally expressed at the corticostriatal synapses, since blockage of these channels result in PPR decrease. Our results also help to explain how synaptic activity may become sensitive to extracellular signals mediated by G-protein coupled receptors. A vast repertoire of receptors may influence neurotransmitter release in an indirect manner through regulation of K(IR)3 channels.

  10. Crystallization field and rate study for the formation of single phase sodium-potassium and potassium clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Guevenir, Oe.; Kalipcilar, H.; Culfaz, A. [Middle East Technical University, Department of Chemical Engineering, 06531 Ankara (Turkey)

    2011-04-15

    Reproducible synthesis of clinoptilolite as the single crystalline phase was achieved in the narrow crystallization field at or around the nominal batch composition of 2.1(Na{sub 2}O+K{sub 2}O):Al{sub 2}O{sub 3}:10SiO{sub 2}:110H{sub 2}O at 140 C. Clinoptilolites of high purity were crystallized in the pure sodium or mixed sodium-potassium cation systems. Partial replacement of hydroxyl anions with the salts of carbonates or chlorides also yielded clinoptilolite as the single crystalline phase although at lower crystallization rates. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. 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.

  12. The development of a potassium-sulfide glass fiber cell and studies on impurities in alkali metal-sulfur cells

    Science.gov (United States)

    Tsang, F. Y.

    1977-01-01

    Potassium sulfur rechargeable cells, having as the electrolyte the thin walls of hollow glass fibers made from permeable glass, were developed. The cells had short lives, probably due to the construction materials and impurities in the potassium. The effect of the impurities in the analogous NA-S system was studied. Calcium, potassium, and NaOH/oxide impurities caused increased resistance or corrosion of the glass fibers. For long lived cell operation, the Na must contain less than 1 ppm Ca and less than a few ppm of hydroxide/oxide. Up to 150 ppm K can be tolerated. After purification of the Na anolyte, cell lifetimes in excess of 1000 deep charge-discharge cycles or over 8 months on continuous cycling at 10-30 percent depth of discharge were obtained.

  13. Chloride is essential for contraction of afferent arterioles after agonists and potassium

    DEFF Research Database (Denmark)

    Jensen, B L; Ellekvist, Peter; Skøtt, O

    1997-01-01

    A depolarizing chloride efflux has been suggested to activate voltage-dependent calcium channels in renal afferent arteriolar smooth muscle cells in response to vasoconstrictors. To test this proposal, rabbit afferent arterioles were microperfused, and the contractile dose responses to norepineph......A depolarizing chloride efflux has been suggested to activate voltage-dependent calcium channels in renal afferent arteriolar smooth muscle cells in response to vasoconstrictors. To test this proposal, rabbit afferent arterioles were microperfused, and the contractile dose responses......). Reintroduction of chloride fully restored the sensitivity to norepinephrine. Contractions after ANG II and potassium were totally abolished in the absence of chloride (n = 6). In additional experiments (n = 7), the arteriolar contraction to 100 mM potassium was abolished only 1 min after removal of extracellular...... chloride. We conclude that norepinephrine and ANG II use different mechanisms for contraction and that extracellular chloride is essential for contraction in afferent arterioles after activation of voltage-dependent calcium channels. We suggest that a chloride influx pathway is activated concomitantly...

  14. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red...

  15. M-type potassium channels modulate Schaffer collateral-CA1 glutamatergic synaptic transmission.

    Science.gov (United States)

    Sun, Jianli; Kapur, Jaideep

    2012-08-15

    Previous studies have suggested that muscarinic receptor activation modulates glutamatergic transmission. M-type potassium channels mediate the effects of muscarinic activation in the hippocampus, and it has been proposed that they modulate glutamatergic synaptic transmission. We tested whether M1 muscarinic receptor activation enhances glutamatergic synaptic transmission via the inhibition of the M-type potassium channels that are present in Schaffer collateral axons and terminals. Miniature excitatory postsynaptic currents (mEPSCs) were recorded from CA1 pyramidal neurons. The M1 receptor agonist, NcN-A-343, increased the frequency of mEPSCs, but did not alter their amplitude. The M-channel blocker XE991 and its analogue linopirdine also increased the frequency of mEPSCs. Flupirtine, which opens M-channels, had the opposite effect. XE991 did not enhance mEPSCs frequency in a calcium-free external medium. Blocking P/Q- and N-type calcium channels abolished the effect of XE991 on mEPSCs. These data suggested that the inhibition of M-channels increases presynaptic calcium-dependent glutamate release in CA1 pyramidal neurons. The effects of these agents on the membrane potentials of presynaptic CA3 pyramidal neurons were studied using current clamp recordings; activation of M1 receptors and blocking M-channels depolarized neurons and increased burst firing. The input resistance of CA3 neurons was increased by the application of McN-A-343 and XE991; these effects were consistent with the closure of M-channels. Muscarinic activation inhibits M-channels in CA3 pyramidal neurons and its efferents – Schaffer collateral, which causes the depolarization, activates voltage-gated calcium channels, and ultimately elevates the intracellular calcium concentration to increase the release of glutamate on CA1 pyramidal neurons.

  16. Calcium pretreatment increases thermotolerance of Laminaria japonica sporophytes

    Institute of Scientific and Technical Information of China (English)

    You Wang; Qingyun Yu; Xuexi Tang; Lili Wang

    2009-01-01

    Calcium is a secondary messenger in plant signaling,and its concentration changes spatially and temporally during the course of heat stress.In the present study,potassium antimonate was used to visualize calcium localization in blades of a marine macroalga,the juvenile Laminariajaponica sporophytes under heat stress (25 ℃).Result showed that loosely bound calcium was mainly distributed on the cell wall under normal conditions (10 ℃),and flowed into the cytoplasm when exposed to heat.The simutaneous assay on the antioxidant system changes was performed.Oxidative damage,as measured by generation of reactive oxygen species (ROS) malondialdehyde (MDA) content,increased significantly during heat stress,and calcium pretreatment alleviated oxidative damage.The assay on the activities of six antioxidant enzymes demonstrated that their enzymatic activities were inhibited when exposed to heat stress,but Ca2+ pretreatment effectively attenuated the inhibition.Results in the present study inferred that calcium homeostasis plays an essential role in L.japonica sporophyte when exposed to heat,and calcium pretreatment could improve its thermo-tolerance.

  17. The Ketogenic Diet and Potassium Channel Function

    Science.gov (United States)

    2014-10-01

    The overall objective of this Discovery Award is to explore the hypothesis the ketogenic diet regulates neuronal excitability by influencing...potassium channel activity via the auxiliary potassium channel subunit Kv Beta 2. To test this hypothesis we have examining the impact of the ketogenic diet on...vitro bursting activity (seizures) which is reversed by treatment with the ketogenic diet (KD). Conversely, the latency to the first in vitro burst

  18. Calcium is important forus.

    Institute of Scientific and Technical Information of China (English)

    高利平

    2005-01-01

    Calcium is important for our health.We must have it in our diet to stay well.A good place to get it is from dairy products like milk, cheese and ice cream.One pound of cheese has fifty times the calcium we should have every day.Other foods have less.For example,a pound of beans also has calcium.But it has only three times the amount we ought to have daily.

  19. Using Healthcare Failure Mode and Effect Analysis tool to review the process of ordering and administrating potassium chloride and potassium phosphate.

    Science.gov (United States)

    Esmail, Rosmin; Cummings, Cheryl; Dersch, Deonne; Duchscherer, Greg; Glowa, Judy; Liggett, Gail; Hulme, Terrance

    2005-01-01

    During the spring of 2004, in the Calgary Health Region (CHR) two critical incidents occurred involving patients receiving continuous renal replacement therapy (CRRT) in the intensive care unit (ICU). The outcome of these events resulted in the sudden death of both patients. The Department of Critical Care Medicine's Patient Safety and Adverse Events Team (PSAT), utilized the Healthcare Failure Mode and Effect Analysis (HFMEA) tool to review the process and conditions surrounding the ordering and administration of potassium chloride (KCI) and potassium phosphate (KPO4) in our ICUs. The HFMEA tool and the multidisciplinary team structure provided a solid framework for systematic analysis and prioritization of areas for improvement regarding the use of intravenous, high-concentration KCL and KPO4 in the ICU.

  20. Effect of Calcium Supplementation on Growth, Nutrient Digestibility and Fecal Lactobacilli in Dairy Calves

    Directory of Open Access Journals (Sweden)

    C. Yuangklang

    2010-01-01

    Full Text Available Problem statement: Based on earlier studies in veal calves and rats, the hypothesis tested was that high calcium intakes by ruminating dairy calves reduce fat digestibility, but do not affect growth performance due to enhanced colonization of the intestine with lactobacilli. Approach: In dairy calves that were fed on a combination of milk replacer, concentrate on grass hay, the effects of supplemental calcium on growth, nutrient digestibility and fecal lactobacilli were studied. Four concentrates with different levels of calcium were used. Results: Final body weight and weight gain were raised by the calcium level in the concentrate in a dose-dependent, linear fashion. Apparent digestibility of dry matter, organic matter, crude protein and crude fat were not influenced by the level of calcium in the concentrate. The number of fecal lactobacilli was significantly increased by higher dietary calcium levels, the effect having a linear trend. Calcium intake did not change the number of fecal E. coli. The apparent absorptions of calcium, phosphorus and magnesium were lowered in a linear, dose-dependent fashion by the calcium level in the concentrate. Conclusion: Increased calcium intakes stimulate weight gain in dairy calves fed a combination of milk replacer, concentrate and grass hay. This calcium effect may be related to an enhanced colonization of the intestine with lactobacilli.

  1. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early...

  2. Total ankle joint replacement.

    Science.gov (United States)

    2016-02-01

    Ankle arthritis results in a stiff and painful ankle and can be a major cause of disability. For people with end-stage ankle arthritis, arthrodesis (ankle fusion) is effective at reducing pain in the shorter term, but results in a fixed joint, and over time the loss of mobility places stress on other joints in the foot that may lead to arthritis, pain and dysfunction. Another option is to perform a total ankle joint replacement, with the aim of giving the patient a mobile and pain-free ankle. In this article we review the efficacy of this procedure, including how it compares to ankle arthrodesis, and consider the indications and complications.

  3. Extração simultânea de alumínio, cálcio, magnésio, potássio e sódio do solo com solução de cloreto de amônio Simultaneous extraction of aluminum, calcium, magnesium, potassium, and sodium with ammonium chloride solution

    Directory of Open Access Journals (Sweden)

    R. C. Boeira

    2004-10-01

    Full Text Available Atualmente, alguns laboratórios de análise de solo determinam Al, Ca e Mg trocáveis em extratos de KCl 1 mol L-1 e K e Na na solução extratora Mehlich-1, também usada na extração de fósforo. Outros laboratórios, que empregam a resina trocadora de ânions para P, avaliam também Ca, Mg e K no extrato, não sendo possível determinar Al e Na. Dessa forma, achou-se oportuno avaliar a extração com NH4Cl 1 mol L-1 na determinação simultânea dos cinco cátions trocáveis: Al, Ca, Mg, K e Na, em comparação aos extratores KCl e Mehlich-1. Utilizaram-se amostras coletadas em áreas de cultivo de fruteiras irrigadas da região Nordeste e na área experimental da Embrapa Meio Ambiente em Jaguariúna (SP. Os métodos utilizados foram: (a extração simultânea dos cinco cátions com NH4Cl 1 mol L-1, e (b extração de Ca, Mg e Al com KCl 1 mol L-1, e de K e Na com o extrator Mehlich-1. A solução de NH4Cl 1 mol L-1 apresentou maior capacidade de extração de Mg do solo do que a solução de KCl 1 mol L-1; as duas soluções se equivaleram quanto à capacidade de extração de Ca e de Al. A solução de NH4Cl extraiu mais K e Na do que a solução Mehlich-1. Conclui-se que a solução de NH4Cl é uma opção conveniente para a extração de Al, Ca, Mg, K e Na trocáveis do solo.Currently, part of the soil testing laboratories of Brazil determine exchangeable Al, Ca, and Mg in a 1 mol L-1 KCl soil extract and exchangeable sodium and potassium in the Mehlich-1 soil extract, which is also used for phosphorus extraction. Other laboratories use an anion exchange resin for P and also determine Ca, Mg and K in the same extract, while Al and Na cannot be determined. For this reason, it was considered a good opportunity to evaluate the simultaneous extraction of the five exchangeable cations: Al, Ca, Mg, K, and Na in a 1 mol L-1 NH4Cl solution, and compare the results with those obtained with potassium chloride and Mehlich-1 extractants. The soil

  4. Hyperkalemia caused by rapid red cell transfusion and the potassium absorption filter

    Directory of Open Access Journals (Sweden)

    Yasuhiko Imashuku

    2017-01-01

    Full Text Available We report a case of transient hyperkalemia during hysterectomy after cesarean section, due to preoperatively undiagnosed placenta accreta that caused unforeseen massive hemorrhage and required rapid red cell transfusion. Hyperkalemia-induced by rapid red cell transfusion is a well-known severe complication of transfusion; however, in patients with sudden massive hemorrhage, rapid red cell transfusion is necessary to save their life. In such cases, it is extremely important to monitor serum potassium levels. For an emergency situation, a system should be developed to ensure sufficient preparation for immediate transfusion and laboratory tests. Furthermore, sufficient stock of preparations to treat hyperkalemia, such as calcium preparations, diuretics, glucose, and insulin is required. Moreover, a transfusion filter that absorbs potassium has been developed and is now available for clinical use in Japan. The filter is easy to use and beneficial, and should be prepared when it is available.

  5. Hyperkalemia caused by rapid red cell transfusion and the potassium absorption filter

    Science.gov (United States)

    Imashuku, Yasuhiko; Kitagawa, Hirotoshi; Mizuno, Takayoshi; Fukushima, Yutaka

    2017-01-01

    We report a case of transient hyperkalemia during hysterectomy after cesarean section, due to preoperatively undiagnosed placenta accreta that caused unforeseen massive hemorrhage and required rapid red cell transfusion. Hyperkalemia-induced by rapid red cell transfusion is a well-known severe complication of transfusion; however, in patients with sudden massive hemorrhage, rapid red cell transfusion is necessary to save their life. In such cases, it is extremely important to monitor serum potassium levels. For an emergency situation, a system should be developed to ensure sufficient preparation for immediate transfusion and laboratory tests. Furthermore, sufficient stock of preparations to treat hyperkalemia, such as calcium preparations, diuretics, glucose, and insulin is required. Moreover, a transfusion filter that absorbs potassium has been developed and is now available for clinical use in Japan. The filter is easy to use and beneficial, and should be prepared when it is available. PMID:28217070

  6. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  7. The Optimum Replacement of Weapon

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao; ZHANG Jin-chun

    2002-01-01

    The theory of LCC (Life Cycle Cost) is applied in this paper. The relation between the economic life of weapon and the optimum replacement is analyzed. The method to define the optimum replacement time of weapon is discussed.

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

    Science.gov (United States)

    Jorgensen, Niklas Rye; Teilmann, Stefan Cuoni; Henriksen, Zanne; Civitelli, Roberto; Sorensen, Ole Helmer; Steinberg, Thomas H.

    2003-01-01

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

  9. Power Plant Replacement Study

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Gary

    2010-09-30

    This report represents the final report for the Eastern Illinois University power plant replacement study. It contains all related documentation from consideration of possible solutions to the final recommended option. Included are the economic justifications associated with the chosen solution along with application for environmental permitting for the selected project for construction. This final report will summarize the results of execution of an EPC (energy performance contract) investment grade audit (IGA) which lead to an energy services agreement (ESA). The project includes scope of work to design and install energy conservation measures which are guaranteed by the contractor to be self‐funding over its twenty year contract duration. The cost recovery is derived from systems performance improvements leading to energy savings. The prime focus of this EPC effort is to provide a replacement solution for Eastern Illinois University’s aging and failing circa 1925 central steam production plant. Twenty‐three ECMs were considered viable whose net impact will provide sufficient savings to successfully support the overall project objectives.

  10. Total disc replacement.

    Science.gov (United States)

    Vital, J-M; Boissière, L

    2014-02-01

    Total disc replacement (TDR) (partial disc replacement will not be described) has been used in the lumbar spine since the 1980s, and more recently in the cervical spine. Although the biomechanical concepts are the same and both are inserted through an anterior approach, lumbar TDR is conventionally indicated for chronic low back pain, whereas cervical TDR is used for soft discal hernia resulting in cervicobrachial neuralgia. The insertion technique must be rigorous, with precise centering in the disc space, taking account of vascular anatomy, which is more complex in the lumbar region, particularly proximally to L5-S1. All of the numerous studies, including prospective randomized comparative trials, have demonstrated non-inferiority to fusion, or even short-term superiority regarding speed of improvement. The main implant-related complication is bridging heterotopic ossification with resulting loss of range of motion and increased rates of adjacent segment degeneration, although with an incidence lower than after arthrodesis. A sufficiently long follow-up, which has not yet been reached, will be necessary to establish definitively an advantage for TDR, particularly in the cervical spine. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  11. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    HR/SOC

    2001-01-01

    The French Ministry of Foreign Affairs has informed the Organization that it is shortly to replace all diplomatic cards, special cards and employment permits ('attestations de fonctions') now held by members of the personnel and their families. Between 2 July and 31 December 2001, these cards are to be replaced by secure, computerized equivalents. The old cards may continue to be used until 31 December 2001. For the purposes of the handover, members of the personnel must go personally to the cards office (33/1-015), in order to fill in a 'fiche individuelle' form, taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format. The French card in their possession. An A4 photocopy of the same French card, certified by the cards office as being a true copy. Those members of the personnel whose cards (and/or cards belonging to members of their families) are shortly due to expire, or have recently done...

  12. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    Human Resources Division; Cards.Service@cern.ch

    2001-01-01

    The French Ministry of Foreign Affairs is currently replacing all diplomatic cards, special cards and employment permits («attestations de fonctions») held by members of the personnel and their families. These cards are replaced by secure, computerized equivalents. The old cards may no longer be used after 31 December 2001. For the purposes of the handover, members of the personnel must go personally to the cards office (33/1-015) between 8h30 and 12h30, in order to fill in a «fiche individuelle» form, taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format, the French card in their possession, an A4 photocopy of the same French card, certified by the cards office as being a true copy. Those members of the personnel whose cards (and/or cards belonging to members of their families) are shortly due to expire, or have recently done so, are also requested...

  13. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    Human Resources Division

    2001-01-01

    The French Ministry of Foreign Affairs has informed the Organization that it is shortly to replace all diplomatic cards, special cards and employment permits ('attestations de fonctions') now held by members of the personnel and their families. Between 2 July and 31 December 2001, these cards are to be replaced by secure, computerized equivalents. The old cards may continue to be used until 31 December 2001. For the purposes of the handover, members of the personnel are asked to go to the cards office (33/1-015), taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format, The French card in their possession, an A4 photocopy of the same French card, certified by the cards office as being a true copy. Those members of the personnel whose cards (and/or cards belonging to members of their families) are shortly due to expire, or have recently done so, are also requested to take these items to the c...

  14. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    Human Resources Division

    2001-01-01

    The French Ministry of Foreign Affairs has informed the Organization that it is shortly to replace all diplomatic cards, special cards and employment permits ('attestations de fonctions') now held by members of the personnel and their families. Between 2 July and 31 December 2001, these cards are to be replaced by secure, computerized equivalents. A 'personnel office' stamped photocopy of the old cards may continue to be used until 31 December 2001. For the purposes of the handover, members of the personnel must go personally to the cards office (33/1-015), between 8:30 and 12:30, in order to fill a 'fiche individuelle' form (in black ink only), which has to be personally signed by themselves and another separately signed by members of their family, taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format (signed on the back) The French card in their possession an A4 photocopy of the same Fre...

  15. Power Plant Replacement Study

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Gary

    2010-09-30

    This report represents the final report for the Eastern Illinois University power plant replacement study. It contains all related documentation from consideration of possible solutions to the final recommended option. Included are the economic justifications associated with the chosen solution along with application for environmental permitting for the selected project for construction. This final report will summarize the results of execution of an EPC (energy performance contract) investment grade audit (IGA) which lead to an energy services agreement (ESA). The project includes scope of work to design and install energy conservation measures which are guaranteed by the contractor to be self-funding over its twenty year contract duration. The cost recovery is derived from systems performance improvements leading to energy savings. The prime focus of this EPC effort is to provide a replacement solution for Eastern Illinois University's aging and failing circa 1925 central steam production plant. Twenty-three ECMs were considered viable whose net impact will provide sufficient savings to successfully support the overall project objectives.

  16. Faster Replacement Paths

    CERN Document Server

    Williams, Virginia Vassilevska

    2010-01-01

    The replacement paths problem for directed graphs is to find for given nodes s and t and every edge e on the shortest path between them, the shortest path between s and t which avoids e. For unweighted directed graphs on n vertices, the best known algorithm runtime was \\tilde{O}(n^{2.5}) by Roditty and Zwick. For graphs with integer weights in {-M,...,M}, Weimann and Yuster recently showed that one can use fast matrix multiplication and solve the problem in O(Mn^{2.584}) time, a runtime which would be O(Mn^{2.33}) if the exponent \\omega of matrix multiplication is 2. We improve both of these algorithms. Our new algorithm also relies on fast matrix multiplication and runs in O(M n^{\\omega} polylog(n)) time if \\omega>2 and O(n^{2+\\eps}) for any \\eps>0 if \\omega=2. Our result shows that, at least for small integer weights, the replacement paths problem in directed graphs may be easier than the related all pairs shortest paths problem in directed graphs, as the current best runtime for the latter is \\Omega(n^{2.5...

  17. Power Plant Replacement Study

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Gary

    2010-09-30

    This report represents the final report for the Eastern Illinois University power plant replacement study. It contains all related documentation from consideration of possible solutions to the final recommended option. Included are the economic justifications associated with the chosen solution along with application for environmental permitting for the selected project for construction. This final report will summarize the results of execution of an EPC (energy performance contract) investment grade audit (IGA) which lead to an energy services agreement (ESA). The project includes scope of work to design and install energy conservation measures which are guaranteed by the contractor to be self-funding over its twenty year contract duration. The cost recovery is derived from systems performance improvements leading to energy savings. The prime focus of this EPC effort is to provide a replacement solution for Eastern Illinois University’s aging and failing circa 1925 central steam production plant. Twenty-three ECMs were considered viable whose net impact will provide sufficient savings to successfully support the overall project objectives.

  18. Kv3 voltage-gated potassium channels regulate neurotransmitter release from mouse motor nerve terminals.

    Science.gov (United States)

    Brooke, Ruth E; Moores, Thomas S; Morris, Neil P; Parson, Simon H; Deuchars, Jim

    2004-12-01

    Voltage-gated potassium (Kv) channels are critical to regulation of neurotransmitter release throughout the nervous system but the roles and identity of the subtypes involved remain unclear. Here we show that Kv3 channels regulate transmitter release at the mouse neuromuscular junction (NMJ). Light- and electron-microscopic immunohistochemistry revealed Kv3.3 and Kv3.4 subunits within all motor nerve terminals of muscles examined [transversus abdominus, lumbrical and flexor digitorum brevis (FDB)]. To determine the roles of these Kv3 subunits, intracellular recordings were made of end-plate potentials (EPPs) in FDB muscle fibres evoked by electrical stimulation of tibial nerve. Tetraethylammonium (TEA) applied at low concentrations (0.05-0.5 mM), which blocks only a few known potassium channels including Kv3 channels, did not affect muscle fibre resting potential but significantly increased the amplitude of all EPPs tested. Significantly, this effect of TEA was still observed in the presence of the large-conductance calcium-activated potassium channel blockers iberiotoxin (25-150 nM) and Penitrem A (100 nM), suggesting a selective action on Kv3 subunits. Consistent with this, 15-microM 4-aminopyridine, which blocks Kv3 but not large-conductance calcium-activated potassium channels, enhanced evoked EPP amplitude. Unexpectedly, blood-depressing substance-I, a toxin selective for Kv3.4 subunits, had no effect at 0.05-1 microM. The combined presynaptic localization of Kv3 subunits and pharmacological enhancement of EPP amplitude indicate that Kv3 channels regulate neurotransmitter release from presynaptic terminals at the NMJ.

  19. 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...

  20. Mechanism of electromechanical coupling in voltage-gated potassium channels

    Directory of Open Access Journals (Sweden)

    Rikard eBlunck

    2012-09-01

    Full Text Available Voltage-gated ion channels play a central role in the generation of action potentials in the nervous system. They are selective for one type of ion – sodium, calcium or potassium. Voltage-gated ion channels are composed of a central pore that allows ions to pass through the membrane and four peripheral voltage sensing domains that respond to changes in the membrane potential. Upon depolarization, voltage sensors in voltage-gated potassium channels (Kv undergo conformational changes driven by positive charges in the S4 segment and aided by pairwise electrostatic interactions with the surrounding voltage sensor. Structure-function relations of Kv channels have been investigated in detail, and the resulting models on the movement of the voltage sensors now converge to a consensus; the S4 segment undergoes a combined movement of rotation, tilt and vertical displacement in order to bring 3-4 e+ each through the electric field focused in this region. Nevertheless, the mechanism by which the voltage sensor movement leads to pore opening, the electromechanical coupling, is still not fully understood. Thus, recently, electromechanical coupling in different Kv channels has been investigated with a multitude of techniques including electrophysiology, 3D crystal structures, fluorescence spectroscopy and molecular dynamics simulations. Evidently, the S4-S5 linker, the covalent link between the voltage sensor and pore, plays a crucial role. The linker transfers the energy from the voltage sensor movement to the pore domain via an interaction with the S6 C-termini, which are pulled open during gating. In addition, other contact regions have been proposed. This review aims to provide (i an in-depth comparison of the molecular mechanisms of electromechanical coupling in different Kv channels; (ii insight as to how the voltage sensor and pore domain influence one another; and (iii theoretical predictions on the movement of the cytosolic face of the KV channels

  1. Calcium signaling in neurodegeneration

    Directory of Open Access Journals (Sweden)

    Dreses-Werringloer Ute

    2009-05-01

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

  2. Toleration, Synthesis or Replacement?

    DEFF Research Database (Denmark)

    Holtermann, Jakob v. H.; Madsen, Mikael Rask

    2016-01-01

    to have considerable problems keeping a clear focus on the key question: What are the implications of this empirical turn in terms of philosophy of legal science, of the social understanding of IL, and, not least, of the place of doctrinal scholarship after the alleged Wende? What is needed, we argue......, in order to answer is not yet another partisan suggestion, but rather an attempt at making intelligible both the oppositions and the possibilities of synthesis between normative and empirical approaches to law. Based on our assessment and rational reconstruction of current arguments and positions, we...... therefore outline a taxonomy consisting of the following three basic, ideal-types in terms of the epistemological understanding of the interface of law and empirical studies: toleration, synthesis and replacement. This tripartite model proves useful with a view to teasing out and better articulating...

  3. Inhibition of collagen synthesis by select calcium and sodium channel blockers can be mitigated by ascorbic acid and ascorbyl palmitate

    OpenAIRE

    Ivanov, Vadim; Ivanova, Svetlana; KALINOVSKY, TATIANA; NIEDZWIECKI, ALEKSANDRA; Rath, Matthias

    2016-01-01

    Calcium, sodium and potassium channel blockers are widely prescribed medications for a variety of health problems, most frequently for cardiac arrhythmias, hypertension, angina pectoris and other disorders. However, chronic application of channel blockers is associated with numerous side effects, including worsening cardiac pathology. For example, nifedipine, a calcium-channel blocker was found to be associated with increased mortality and increased risk for myocardial infarction. In addition...

  4. State-dependent FRET reports calcium- and voltage-dependent gating-ring motions in BK channels

    OpenAIRE

    Miranda, Pablo; Contreras, Jorge E.; Plested, Andrew J. R.; Sigworth, Fred J.; Holmgren, Miguel; Giraldez, Teresa

    2013-01-01

    Large-conductance voltage- and calcium-dependent potassium channels (BK, “Big K+”) are important controllers of cell excitability. In the BK channel, a large C-terminal intracellular region containing a “gating-ring” structure has been proposed to transduce Ca2+ binding into channel opening. Using patch-clamp fluorometry, we have investigated the calcium and voltage dependence of conformational changes of the gating-ring region of BK channels, while simultaneously monitoring channel conductan...

  5. Development of potassium ion conducting hollow glass fibers. [potassium sulfur battery

    Science.gov (United States)

    Tsang, F. Y.

    1974-01-01

    Potassium ion conducting glasses, chemically resistant to potassium, potassium sulfide and sulfur, were made and their possible utility as the membrane material for a potassium/sulfur battery was evaluated. At least one satisfactory candidate was found. It possesses an electrical resistance which makes it usable as a membrane in the form of a fine hollow fiber. It's chemical and electrochemical resistances are excellent. The other aspects of the possible potassium sulfur battery utilizing such fine hollow fibers, including the header (or tube sheet) and a cathode current collector were studied. Several cathode materials were found to be satisfactory. None of the tube sheet materials studied possessed all the desired properties. Multi-fiber cells had very limited life-time due to physical failure of fibers at the fiber/tube sheet junctions.

  6. Structural Role of Alkali Cations in Calcium Aluminosilicate Glasses as Examined Using Oxygen-17 Solid-State Nuclear Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Sukenaga, Sohei; Kanehashi, Koji; Shibata, Hiroyuki; Saito, Noritaka; Nakashima, Kunihiko

    2016-08-01

    The structural roles of alkali and calcium cations are important for understanding the physical and chemical properties of aluminosilicate melts and glasses. Recently, oxygen-17 nuclear magnetic resonance (17O NMR) studies of calcium-sodium aluminosilicate glasses showed that these structural roles are not randomly given, but rather each cation has its own preferential role. However, the relationship between cation type and role preference in calcium aluminosilicate glass is not completely understood. In the present study, the structural roles of lithium, sodium, and potassium cations in selected calcium aluminosilicate glasses are investigated using 17O solid-state NMR experiments. Data from these experiments clearly show that potassium cations have a notably stronger tendency to act as charge compensators within the network structure, compared to sodium and lithium cations. The result of 17O NMR experiment also showed that sodium and lithium cations in part act as network modifier alongside with calcium cations.

  7. Immersion Freezing of Potassium-feldspar and related Natural Samples

    Science.gov (United States)

    Zolles, Tobias; Burkart, Julia; Grothe, Hinrich

    2014-05-01

    Ice nucleation activities of mineral dust particles were investigated. The experiments were carried out using cryo-microscopy which is an oil-emulsion based method. The immersion freezing mode was addressed with this experimental setup. The studied samples were common inorganic atmospheric aerosols. Single minerals and natural samples were tested [1]. Mineral dust particles are active ice nuclei in the immersion freezing mode up to 256 K. Only recently potassium-feldspar has been identified as the by far most active ice nucleus followed by other silicates [2, 3]. Natural samples which contain more than 5% K-feldspar are also active. The activity of K-feldspar can be attributed to its surface structure and the presence of potassium ions in the surface. Ice nucleation on mineral dust particles takes place at certain nucleation sites. These sites are domains of molecular sites where water is stabilized in an ice-like structure. To form a good ice nucleation site, the site density of molecular sites needs to be high. More molecular sites are able to form larger domains on the surface, leading to better nucleation sites. This suggests further that the nucleation temperature of mineral dust particles scales with the surface area. The exact configuration of a molecular site is material specific and influenced by the local chemistry and structure of the dust particle surface. A favourable arrangement of the functional groups like surface hydroxyl and oxygen is proposed for the K-feldspar. Potassium ions seem to have a positive or neutral effect on the ice nucleation property of a silicate surface while cations with a higher charge density like calcium and sodium have a negative influence. K-feldspar is abundant in the environment and actually is the most important dust ice nucleus in the atmosphere. The nucleation temperatures of the K-feldspar particles are sufficient to enable further meteorological glaciation processes in high altitude clouds. References [1] Zolles, T

  8. 银杏苦内酯B对缺血豚鼠心室肌动作电位、L-型钙电流和延迟整流钾电流的作用%THE EFFECT OF GINKGOLIDE B ON ACTION POTENTIAL,L-TYPE CALCIUM CURRENT AND DELAYED RECTIFIER POTASSIUM CURRENT IN ISCHEMIC GUINEA PIG VENTRICULAR MYOCYTES

    Institute of Scientific and Technical Information of China (English)

    祁小燕; 张志雄; 崔启启; 施渭彬; 徐有秋

    2004-01-01

    目的:研究银杏苦内酯B对正常和缺血心室肌细胞动作电位(action potential,AP),L-型钙电流(L-type calcium current,ICa-L)、延迟整流钾电流(Delayed Rectifier Currennt,IK)的影响.方法:用常规细胞内微电极方法记录豚鼠心室肌细胞动作电位,用全细胞膜片钳技术记录游离心室肌细胞离子流.结果:①在生理条件下,银杏苦内酯B可缩短心室肌细胞动作电位时程 (action potential duration,APD),但对AP其他参数无影响,银杏苦内酯B可增大IK,呈浓度依赖性,但对ICa-L无显著作用;②在缺血条件下,APD50、APD90明显缩短,RP、APA减小,Vmax减慢,而银杏苦内酯B则可延缓和减轻缺血所引起上述参数的变化;3.在缺血条件下,IK和ICa-L均受到抑制,但加入银杏苦内酯B后可逆转缺血所造成这两种离子流的减小.结论:银杏苦内酯B可对抗心肌缺血所引起的心肌电生理的变化,提示银杏苦内酯B可预防心律失常的发生.

  9. Using continuous renal replacement therapy to manage patients of shock and acute renal failure

    Directory of Open Access Journals (Sweden)

    Soni Sachin

    2009-01-01

    Full Text Available Background: The incidence of acute renal failure (ARF in the hospital setting is increasing. It portends excessive morbidity and mortality and a considerable burden on hospital resources. Extracorporeal therapies show promise in the management of patients with shock and ARF. It is said that the potential of such therapy goes beyond just providing renal support. The aim of our study was to analyze the clinical setting and outcomes of critically ill ARF patients managed with continuous renal replacement therapy (CRRT. Patients and Methods: Ours was a retrospective study of 50 patients treated between January 2004 and November 2005. These 50 patients were in clinical shock and had concomitant ARF. All of these patients underwent CVVHDF (continuous veno-venous hemodiafiltration in the intensive care unit. For the purpose of this study, shock was defined as systolic BP < 100 mm Hg in spite of administration of one or more inotropic agents. SOFA (Sequential Organ Failure Assessment score before initiation of dialysis support was recorded in all cases. CVVHDF was performed using the Diapact ® (Braun CRRT machine. The vascular access used was as follows: femoral in 32, internal jugular in 8, arteriovenous fistula (AVF in 4, and subclavian in 6 patients. We used 0.9% or 0.45% (half-normal saline as a prefilter replacement, with addition of 10% calcium gluconate, magnesium sulphate, sodium bicarbonate, and potassium chloride in separate units, while maintaining careful monitoring of electrolytes. Anticoagulation of the extracorporeal circuit was achieved with systemic heparin in 26 patients; frequent saline flushes were used in the other 24 patients. Results: Of the 50 patients studied, 29 were males and 21 females (1.4:1. The average age was 52.88 years (range: 20-75 years. Causes of ARF included sepsis in 24 (48%, hemodynamically mediated renal failure (HMRF in 18 (36%, and acute over chronic kidney disease in 8 (16% patients. The overall mortality was

  10. Performan Ayam Broiler yang diberi Ransum Mengandung Potassium Diformate Sebagai Pengganti Flavomycin

    Directory of Open Access Journals (Sweden)

    Nahrowi Ramli

    2008-04-01

    Full Text Available Performance of broilers fed diets containing potassium diformate to replace flavomycin ABSTRACT. The aim of this research was to study the effect of potassium-diformate (PD on broiler performance. One hundred and twenty old chicks of Cobb strain were divided into fifteen groups and feed one of five treatments, namely: P1 (control diet, P2 (P1 + 0,5%PD, P3(P1 + 1%PD, P4 (P1 + 1,5%PD and P5 (P1 + antibiotic. Data from Completely Randomized Design were analyzed by ANOVA and any significant among them were used contrast orthogonal test. Treatments did not impact on feed consumption, mortality and percentage of viscera, but the groups treated with 1 and 1.5% PD and flavomicyne antibiotic had significant improvement on body weight gain (P<0.169 and feed efficiency (P<0.05. It is concluded that addition of 1-1.5% potassium-diformate in the broiler’s diet could improve feed efficiency and replace flavomycine antibiotic as growth promotors without influencing the performance of viscera.

  11. Performan Ayam Broiler yang diberi Ransum Mengandung Potassium Diformate Sebagai Pengganti Flavomycin

    Directory of Open Access Journals (Sweden)

    Nahrowi Ramli

    2008-04-01

    Full Text Available Performance of broilers fed diets containing potassium diformate to replace flavomycin ABSTRACT. The aim of this research was to study the effect of potassium-diformate (PD on broiler performance. One hundred and twenty old chicks of Cobb strain were divided into fifteen groups and feed one of five treatments, namely: P1 (control diet, P2 (P1 + 0,5%PD, P3(P1 + 1%PD, P4 (P1 + 1,5%PD and P5 (P1 + antibiotic. Data from Completely Randomized Design were analyzed by ANOVA and any significant among them were used contrast orthogonal test. Treatments did not impact on feed consumption, mortality and percentage of viscera, but the groups treated with 1 and 1.5% PD and flavomicyne antibiotic had significant improvement on body weight gain (P<0.169 and feed efficiency (P<0.05. It is concluded that addition of 1-1.5% potassium-diformate in the broiler’s diet could improve feed efficiency and replace flavomycine antibiotic as growth promotors without influencing the performance of viscera.

  12. Serum Potassium Levels in Sigmoid Volvulus

    Science.gov (United States)

    Atamanalp, S. Selcuk; Keles, M. Sait; Aydinli, Bulent

    2009-01-01

    Objective: This study aimed to determine the serum potassium concentrations in patients with sigmoid volvulus (SV), which is a rare large bowel obstruction. Materials and Methods: The records of 86 patients with SV were reviewed retrospectively, while the records of 41 patients diagnosed with obstructive rectosigmoid cancer (ORC) were considered as the control group and as such, served as a source for comparison. Results: The analysis revealed a mean serum potassium concentration of 3.9 ± 0.6 mEq/L for the patients with SV, while the mean potassium concentration was 3.9 ± 0.5 mEq/L for the patients diagnosed with ORC (t:0.1, P>0.05). The number of hypokalemic and hyperkalemic patients identified in this study sample were 11 versus 5 patients and 1 versus 0 patients, respectively for the SV and ORC groups (x2 = 0.1 and 0.5, respectively with a P>0.05). Conclusions: No cause-and-effect relationship was observed between the serum potassium concentrations and SV. The serum potassium concentration is not pathognomonic for SV. PMID:25610090

  13. Elasticity of calcium and calcium-sodium amphiboles

    Science.gov (United States)

    Brown, J. Michael; Abramson, Evan H.

    2016-12-01

    Measurements of single-crystal elastic moduli under ambient conditions are reported for nine calcium to calcium-sodium amphiboles that lie in the composition range of common crustal constituents. Velocities of body and surface acoustic waves measured by Impulsive Stimulated Light Scattering (ISLS) were inverted to determine the 13 moduli characterizing these monoclinic samples. Moduli show a consistent pattern: C33 > C22 > C11 and C23 > C12 > C13 and C44 > C55 ∼ C66 and for the uniquely monoclinic moduli, |C35| ≫ C46 ∼ |C25| > |C15| ∼ 0. Most of the compositionally-induced variance of moduli is associated with aluminum and iron content. Seven moduli (C11C12C13C22C44C55C66) increase with increasing aluminum while all diagonal moduli decrease with increasing iron. Three moduli (C11, C13 and C44) increase with increasing sodium and potassium occupancy in A-sites. The uniquely monoclinic moduli (C15C25 and C35) have no significant compositional dependence. Moduli associated with the a∗ direction (C11C12C13C55 and C66) are substantially smaller than values associated with structurally and chemically related clinopyroxenes. Other moduli are more similar for both inosilicates. The isotropically averaged adiabatic bulk modulus does not vary with iron content but increases with aluminum content from 85 GPa for tremolite to 99 GPa for pargasite. Increasing iron reduces while increasing aluminum increases the isotropic shear modulus which ranges from 47 GPa for ferro-actinolite to 64 GPa for pargasite. These results exhibit far greater anisotropy and higher velocities than apparent in earlier work. Quasi-longitudinal velocities are as fast as ∼9 km/s and (intermediate between the a∗- and c-axes) are as slow as ∼6 km/s. Voigt-Reuss-Hill averaging based on prior single crystal moduli resulted in calculated rock velocities lower than laboratory measurements, leading to adoption of the (higher velocity) Voigt bound. Thus, former uses of the upper Voigt bound can

  14. Calcium Unresponsive Hypocalcemic Tetany: Gitelman Syndrome with Hypocalcemia

    Directory of Open Access Journals (Sweden)

    Madhav Desai

    2013-01-01

    Full Text Available Introduction. Gitelman’s syndrome (GS is autosomal recessive renal tubular disorder characterized by hypokalemia, hypomagnesemia, hypocalciuria, metabolic alkalosis, and hyperreninemic hyperaldosteronism. It is usually associated with normal serum calcium. We report a patient presented with hypocalcemic tetany, and evaluation showed Gitelman’s syndrome with hypocalcemia. Case Report. A 28-year-old woman presented with cramps of the arms, legs, fatigue, and carpal spasms of one week duration. She has history of similar episodes on and off for the past two years. Her blood pressure was 98/66 mmHg. Chvostek’s sign and Trousseau’s sign were positive. Evaluation showed hypokalemia, hypocalcemia, hypomagnesemia, metabolic alkalosis, and hypocalciuria. Self-medication, diuretic use, laxative abuse, persistent vomiting, and diarrhoea were ruled out. Urinary prostaglandins and genetic testing could not be done because of nonavailability. To differentiate Gitelman syndrome from Bartter’s syndrome (BS, thiazide loading test was done. It showed blunted fractional chloride excretion. GS was confirmed and patient was treated with spironolactone along with magnesium, calcium, and potassium supplementation. Symptomatically, she improved and did not develop episodes of tetany again. Conclusion. In tetany patient along with serum calcium measurement, serum magnesium, serum potassium, and arterial blood gases should be measured. Even though hypocalcemia in Gitelman syndrome is rare, it still can occur.

  15. Calcium unresponsive hypocalcemic tetany: gitelman syndrome with hypocalcemia.

    Science.gov (United States)

    Desai, Madhav; Kolla, Praveen Kumar; Reddy, P L Venkata Pakki

    2013-01-01

    Introduction. Gitelman's syndrome (GS) is autosomal recessive renal tubular disorder characterized by hypokalemia, hypomagnesemia, hypocalciuria, metabolic alkalosis, and hyperreninemic hyperaldosteronism. It is usually associated with normal serum calcium. We report a patient presented with hypocalcemic tetany, and evaluation showed Gitelman's syndrome with hypocalcemia. Case Report. A 28-year-old woman presented with cramps of the arms, legs, fatigue, and carpal spasms of one week duration. She has history of similar episodes on and off for the past two years. Her blood pressure was 98/66 mmHg. Chvostek's sign and Trousseau's sign were positive. Evaluation showed hypokalemia, hypocalcemia, hypomagnesemia, metabolic alkalosis, and hypocalciuria. Self-medication, diuretic use, laxative abuse, persistent vomiting, and diarrhoea were ruled out. Urinary prostaglandins and genetic testing could not be done because of nonavailability. To differentiate Gitelman syndrome from Bartter's syndrome (BS), thiazide loading test was done. It showed blunted fractional chloride excretion. GS was confirmed and patient was treated with spironolactone along with magnesium, calcium, and potassium supplementation. Symptomatically, she improved and did not develop episodes of tetany again. Conclusion. In tetany patient along with serum calcium measurement, serum magnesium, serum potassium, and arterial blood gases should be measured. Even though hypocalcemia in Gitelman syndrome is rare, it still can occur.

  16. Role of calcium in the constriction of isolated cerebral arteries

    Energy Technology Data Exchange (ETDEWEB)

    Wendling, W.W.

    1987-01-01

    Calcium entry blockers (CEB) have been used in the experimental treatment or prevention of many cerebrovascular disorders including stroke, post-ischemic hypoperfusion after cardiac arrest, cerebral vasospasm after subarachnoid hemorrhage, and migraine headache. However, the mechanism of action of these drugs on the cerebral circulation is poorly understood. This study examined the effects of calcium antagonists, Ca/sup 2 +/-deficient solutions, and vasocostrictors on cerebrovascular tone and /sup 45/Ca fluxes, to determine the role of calcium in cerebral arterial constriction. A Scatchard plot of /sup 45/Ca binding to BMCA showed that Ca/sup 2 +/ was bound at either low or high affinity binding sties. The four vasoconstrictors (potassium, serotonin, PGF/sub 2 ..cap alpha../, or SQ-26,655) each increased low affinity /sup 45/Ca uptake into BMCA. The results demonstrate that: (1) Potassium and serotonin constrict BMCA mainly by promoting Ca/sup 2 +/ influx through CEB-sensitive channels; (2) PGF/sub 2 ..cap alpha../ and SQ-26,655 constrict BMCA in part by promoting Ca/sup 2 +/ influx through CEB-sensitive channels, and in part by releasing Ca/sup 2 +/ from depletable internal stores; (3) The major action of CEB on BMCA is to block vasoconstrictor-induced Ca/sup 2 +/ uptake through both potential-operated (K/sup +/-stimulated) and receptor-operated channels.

  17. Characteristics of Potassium-Enriched, Flue-Cured Tobacco Genotype in Potassium Absorption,Accumulation,and In-Ward Potassium Currents of Root Cortex

    Institute of Scientific and Technical Information of China (English)

    YNAG Tie-zhao; LU Li-ming; XIA Wei; FAN Jin-hua

    2007-01-01

    This study was to investigate the main traits of potassium-enriched,flue-cured tobacco genotypes related to potassium absorption,accumulation,and in-ward potassium currents of the root cortex.Hydroponic methods,K+-depletion methods,and patch-clamp,whole-cell recordings were conducted to study the accumulation of dry matter and potassium in different organs,and to measure potassium absorption and dynamic and in-ward potassium currents in potassium-enriched,fluecured tobacco genotypes.The average dry weights of leaves and whole plant of potassium-enriched,flue-cured tobacco genotype ND202 were 10.20,and 14.85g,respectively,higher than JYH(8.50 and 13.11g,respectively)and NC2326(8.39 and 12.72g,respectively),when potassium concentration in the solution ranged from 0.1 to 50mmol L-1.Potassium accumulation in the leaves of ND202 was 18.6% higher than JYH and 34% higher than NC2326 when potassium concentration in the solution was superior to 0.5mmol L-1.The Vmax(the maximum velocity)of ND202 was 118.11μmol FW g-1h-1,obviously higher than that of JYH(58.87 μmol FW g-1 h-1)and NC2326(64.40μmol FW g-1 h-1).In the in-ward potassium currents,the absolute value of current density(pA/pF)of ND202 was 60,higher than that of JYH(50)and NC2326(40).Potassium concentration in leaves,Vmax and in-ward potassium currents,could be used to screen potassium-enriched,flue-cured tobacco genotypes.

  18. From Milk to Bones, Moving Calcium Through the Body: Calcium Kinetics During Space Flight

    Science.gov (United States)

    Smith, Scott; Bloomberg, Jacob; Lee, Angie (Technical Monitor)

    2002-01-01

    Did you know that when astronauts are in space, their height increases about two inches? This happens because the weightlessness of space allows the spine, usually compressed in Earth's gravity, to expand. While this change is relatively harmless, other more serious things can happen with extended stays in weightlessness, notably bone loss. From previous experiments, scientists have observed that astronauts lose bone mass at a rate of about one percent per month during flight. Scientists know that bone is a dynamic tissue - continually being made and repaired by specialized bone cells throughout life. Certain cells produce new bone, while other cells are responsible for removing and replacing old bone. Research on the mechanisms of bone metabolism and the effects of space flight on its formation and repair are part of the exciting studies that will be performed during STS-107. Calcium plays a central role because 1) it gives strength and structure to bone and 2) all types of cells require it to function normally. Ninety-nine percent of calcium in the body is stored in the skeleton. However, calcium may be released, or resorbed, from bone to provide for other tissues when you are not eating. To better understand how and why weightlessness induces bone loss, astronauts will participate in a study of calcium kinetics - that is, the movement of calcium through the body, including absorption from food, and its role in the formation and breakdown of bone.

  19. POTASSIUM MEASUREMENT: CAUSES OF ERRORS IN MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Kavitha

    2014-07-01

    Full Text Available It is not a easy task to recognize the errors in potassium measurement in the lab. Falsely elevated potassium levels if goes unrecognized by the lab and clinician, it is difficult to treat masked hypokalemic state, which is again a medical emergency. Such cases require proper monitoring by the clinician, so that cases with such history of pseudohyperkalemia which cannot be easily identified in the laboratory should not go unrecognized by clinician. The aim of this article is to discuss the causes and mechanisms of spuriously elevated potassium and minimize the factors causing pseudohyperkalemia. Literature search performed on pubmed using terms “pseudohyperkalemia”, “spurious hyperkalemia”, “and masked hyperkalemia”, “reverse pseudohyperkalemia”, “factitious hyperkalemia”.

  20. Potassium permanganate ingestion as a suicide attempt

    Directory of Open Access Journals (Sweden)

    Tuba Cimilli Ozturk

    2012-01-01

    Full Text Available Potassium permanganate is a highly corrosive, water-soluble oxidizing antiseptic. A 68- year-old female patient was admitted to our Emergency Department after ingestion of 3 tablets of 250 mg potassium permanganate as a suicide attempt. The physical exam revealed brown stained lesions in the oropharynx. Emergency endoscopy was performed by the gastroenterologist after the third hour of ingestion. Emergency endoscopy revealed multiple superficial (Grade I-II lesions on the esophagus and cardia, which were considered secondary to the caustic substance. The mainstay in the treatment of potassium permanganate is supportive and the immediate priority is to secure the airway. Emergency endoscopy is an important tool used to evaluate the location and severity of injury to the esophagus, stomach and duodenum after caustic ingestion. Patients with signs and symptoms of intentional ingestion should undergo endoscopy within 12 to 24 h to define the extent of the disease.

  1. Potassium channels in pulmonary arterial hypertension.

    Science.gov (United States)

    Boucherat, Olivier; Chabot, Sophie; Antigny, Fabrice; Perros, Frédéric; Provencher, Steeve; Bonnet, Sébastien

    2015-10-01

    Pulmonary arterial hypertension (PAH) is a devastating cardiopulmonary disorder with various origins. All forms of PAH share a common pulmonary arteriopathy characterised by vasoconstriction, remodelling of the pre-capillary pulmonary vessel wall, and in situ thrombosis. Although the pathogenesis of PAH is recognised as a complex and multifactorial process, there is growing evidence that potassium channels dysfunction in pulmonary artery smooth muscle cells is a hallmark of PAH. Besides regulating many physiological functions, reduced potassium channels expression and/or activity have significant effects on PAH establishment and progression. This review describes the molecular mechanisms and physiological consequences of potassium channel modulation. Special emphasis is placed on KCNA5 (Kv1.5) and KCNK3 (TASK1), which are considered to play a central role in determining pulmonary vascular tone and may represent attractive therapeutic targets in the treatment of PAH.

  2. Iron replacement therapy

    DEFF Research Database (Denmark)

    Nielsen, Ole Haagen; Coskun, Mehmet; Weiss, Günter

    2016-01-01

    PURPOSE OF REVIEW: Approximately, one-third of the world's population suffers from anemia, and at least half of these cases are because of iron deficiency. With the introduction of new intravenous iron preparations over the last decade, uncertainty has arisen when these compounds should be admini...... treatment, when to follow-up for relapse, which dosage and type of therapy should be recommended or not recommended, and if some patients should not be treated....... be administered and under which circumstances oral therapy is still an appropriate and effective treatment. RECENT FINDINGS: Numerous guidelines are available, but none go into detail about therapeutic start and end points or how iron-deficiency anemia should be best treated depending on the underlying cause...... of iron deficiency or in regard to concomitant underlying or additional diseases. SUMMARY: The study points to major issues to be considered in revisions of future guidelines for the true optimal iron replacement therapy, including how to assess the need for treatment, when to start and when to stop...

  3. A potassium Faraday anomalous dispersion optical filter

    Science.gov (United States)

    Yin, B.; Shay, T. M.

    1992-01-01

    The characteristics of a potassium Faraday anomalous dispersion optical filter operating on the blue and near infrared transitions are calculated. The results show that the filter can be designed to provide high transmission, very narrow pass bandwidth, and low equivalent noise bandwidth. The Faraday anomalous dispersion optical filter (FADOF) provides a narrow pass bandwidth (about GHz) optical filter for laser communications, remote sensing, and lidar. The general theoretical model for the FADOF has been established in our previous paper. In this paper, we have identified the optimum operational conditions for a potassium FADOF operating on the blue and infrared transitions. The signal transmission, bandwidth, and equivalent noise bandwidth (ENBW) are also calculated.

  4. Effect of actin microfilament on potassium current in guinea pig gastric myocytes

    Institute of Scientific and Technical Information of China (English)

    Xiang-Lan Li; Hai-Feng Zheng; Zherg-Yuan Jin; Meng Yang; Zai-Liu Li; Wen-Xie Xu

    2004-01-01

    AIM: To investigate the effect of actin microfilament on potassium current and hyposmotic membrane stretch-induced increase of potassium current in gastric antral circular myocytes of guinea pig.METHODS: Whole-cell patch clamp technique was used to record potassium current in isolated gastric myocyes.RESULTS: When the membrane potential was clamped at-60 mV, an actin microfilament disruptor, cytochanlasin-B(Cyt-B, 20 μmol/L in pipette) increased calcium-activated potassium current (IK(Ca)) and delayed rectifier potassium current (IK(V))to 138.4±14.3% and 142.1±13.1%respectively at +60 mV. In the same condition, an actin microfilament stabilizer phalloidin(20 μmol/L in pipette)inhibited IK(Ca) and IK(V) to 74.2±7.1% and 75.4±9.9%respectively. At the holding potential of -60 mV, hyposmotic membrane stretch increased IK(Ca)and IK(V) by 50.6±9.7%and 24.9±3.3% at +60 mV respectively. In the presence of cytochalasin-B and phalloidin (20 μmol/L, in the pipette)condition, hyposmotic membrane stretch also increased IK(Ca)by 44.5±7.9% and 55.7±9.8% at +60 mV respectively. In the same condition, cytochalasin-B and phalloidin also increased IK(V) by 23.0±5.5% and 30.3±4.5% respectively. However,Cyt-B and phalloidin did not affect the amplitude of hyposmotic membrane stretch-induced increase of IK(Ca)and Ik(V).CONCLUSION: Actin microfilaments regulate the activities of potassium channels, but they are not involved in the process of hyposmotic membrane stretch-induced increase of potassium currents in gastric antral circular myocytes of guinea pig.

  5. Effects of calcium on the steady outward currents at the equator of the rat lens.

    Science.gov (United States)

    Parmelee, J T; Robinson, K R; Patterson, J W

    1985-10-01

    The relationships between calcium and the steady outward currents at the equator of the rat lens were studied using the vibrating probe technique. In a calcium-free medium, the current was greatly increased and it returned to its original level when calcium was restored to the medium. The Ca-free effect was not observed in Na-free medium. Iodoacetate (IAA) inhibited the initial current, but a current then returned which is referred to as a secondary current. The secondary current was not observed in a Ca-free medium and, therefore, it is thought to be a calcium-dependent potassium current. These responses are consistent with effects on potassium efflux measured by others and lend support to the interpretation that the outward currents observed at the equator of the rat lens are potassium currents. The currents are partially inhibited but not abolished in Na-free bathing medium. This is consistent with the view that the inward currents at the optical poles may be related to the influx of sodium.

  6. Calcium and Vitamin D

    Science.gov (United States)

    ... Pizza, cheese, frozen 1 serving 115 mg Pudding, chocolate, prepared with 2% milk 4 oz 160 mg ... Treatment Medication and Treatment Adherence Calcium/Vitamin D Nutrition Overall Health Fractures/Fall Prevention Exercise/Safe Movement ...

  7. 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.

  8. Get Enough Calcium

    Science.gov (United States)

    ... Resources You may also be interested in: Calcium: Shopping list Menopause: Questions for ... A Federal Government website managed by the U.S. Department of Health and Human Services healthfinder.gov is ...

  9. 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.

  10. Calcium and Your Child

    Science.gov (United States)

    ... for dinner. Create mini-pizzas by topping whole-wheat English muffins or bagels with pizza sauce, low- ... Minerals Do I Need to Drink Milk? Lactose Intolerance Becoming a Vegetarian Soy Foods and Health Calcium ...

  11. Using your shoulder after replacement surgery

    Science.gov (United States)

    Joint replacement surgery - using your shoulder; Shoulder replacement surgery - after ... You have had shoulder replacement surgery to replace the bones of your shoulder joint with artificial parts. The parts include a stem made of metal and a ...

  12. Effects of potassium sulfate [K2SO4] on the element contents, polyphenol content, antioxidant and antimicrobial activities of milk thistle [Silybum marianum

    Directory of Open Access Journals (Sweden)

    Gulsum Yaldiz

    2017-01-01

    Abbreviations used: AlCl3: aluminum chloride, Ca+2: calcium, Cl-: chloride, Cr: chromium CE: catechol equivalents, DPPH: 2,2-diphenylpicrylhydrazyl, ABTS: 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid, DAP: diamonyum fosfat, F-: fluoride, Fe: iron, K2SO4: potassium sulfate, K+ : potassium, Li+: lithium, Mg+2 : magnesium, NH4+ : amonyum, Na+: sodium, NO2-: nitrite, NO3-: nitrate, Ni: nickel, NaNO2: sodium nitrite, NaOH: sodium hidroksit. ND: Not detectable, PO4-3: phosphorus, Zn: zinc

  13. Calcium and Calcium-Base Alloys

    Science.gov (United States)

    1949-01-01

    should be satisfactory, because the electrolytic process for •(!>: A. H. Everts and G. D. Baglev’, " Physical «nrt m<„.+„4 i «_ of Calcium«, Electrochem...Rev. Metalurgie , 3j2, (1), 129 (1935). 10 ^sm^mssss^ma^^ extension between two known loads, is preferable to the value of 3,700,000 p.B.i. obtained

  14. Potassium availability to flooded rice in lowland soils

    Directory of Open Access Journals (Sweden)

    Leandro Souza da Silva

    2015-12-01

    Full Text Available Non-exchangeable potassium (K forms are not estimated by usual methods of soil K availability, like Mehlich-1, but they can contribute to K nutrition of flooded rice. This study aimed at evaluating K forms in lowland soils by different chemical methods and associate them to K absorption by flooded rice. Fourteen lowland soils cultivated with flooded rice (IRGA 417 cultivar were sampled and used in a greenhouse experiment. The K forms in the soil samples were extracted before and after rice cultivation by using calcium chlorite, Mehlich-1, sodium tetra phenyl borate (NaTFB and fluorite acid. The K uptake was measured in rice shoots. There was a wide variation in K forms among the lowland soils. The variation in the amount of K extracted by using the Mehlich-1 method does not explain the K absorption by irrigated rice plants in every soil. The NaTFB method was more sensitive to evaluate K availability in lowland soils cultivated with flooded rice plants.

  15. Lead interferes with calcium entry through membrane pores

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-06-01

    Calcium is an important intracellular messenger in all cells, represented here by nerve cells and osteoblast-like (OBL) cells. In neurons the intracellular calcium signal is related, e.g., to bioelectric phenomena. In OBL cells the intracellular calcium concentration ([Ca{sup 2+}]{sub i}) plays a role in the intercellular communication via gap junction channels. [Ca{sup 2+}]{sub i} might be affected by lead (Pb{sup 2+}). In the nervous system even low Pb{sup 2+} concentrations impair learning and memory functions. Considering long-term potentiation (LTP) as a model for learning and memory it has been proven that the generation and maintenance of LTP is reduced by Pb{sup 2+} (1-10 {mu}M). As the induction of LTP depends on a rise of [Ca{sup 2+}]{sub i}, we examined the effects of Pb{sup 2+} on [Ca{sup 2+}]{sub i} and on currents through calcium permeable membrane pores in dorsal-root ganglion (DRG) neurons, using calcium measurements (Fura-2/ AM) and whole cell patch clamp techniques. To study the effects of Pb{sup 2+} on intercellular communication via gap junctions we used rat OBL cells investigating interactions of Pb{sup 2+} with electric cell coupling. Furthermore, we examined calcium release activated channel currents (CRACCs) of these cells.Lead (1-10 {mu}M) reduced the stimulated increase of [Ca{sup 2+}]{sub i} in a concentration dependent manner, by reducing both voltage-activated calcium channels (VACCs) and N-methyl-D-aspartate activated calcium channels (NACCs) in neurons. Voltage-activated calcium channel currents (VACCCs) were reduced by Pb{sup 2+} with an IC{sub 50} of 0.46 {mu}M. The effect was quite specific as voltage activated sodium and potassium channel currents were not significantly altered in the same concentration and voltage range. Furthermore, this effect was not voltage dependent and only partly reversible. A 100-fold higher concentration of Pb{sup 2+} (IC{sub 50} of 46 {mu}M) was found for the reduction of NACC currents. A small portion

  16. How Potassium Can Help Control High Blood Pressure

    Science.gov (United States)

    ... natural sources of potassium. For example, a medium banana has about 420 mg of potassium and half ... high blood pressure. Learn more Get a fact sheet on following a heart-healthy diet: English | Spanish ...

  17. Hypoparathyroidism: clinical features, skeletal microstructure and parathyroid hormone replacement

    Science.gov (United States)

    Rubin, Mishaela R.; Bilezikian, John P.

    2013-01-01

    Objective Hypoparathyroidism is a disorder in which parathyroid hormone is deficient in the circulation due most often to immunological destruction of the parathyroids or to their surgical removal. The objective of this work was to define the abnormalities in skeletal microstructure as well as to establish the potential efficacy of PTH(1-84) replacement in this disorder. Subjects and methods Standard histomorphometric and μCT analyses were performed on iliac crest bone biopsies obtained from patients with hypoparathyroidism. Participants were treated with PTH(1-84) for two years. Results Bone density was increased and skeletal features reflected the low turnover state with greater BV/TV, Tb. Wi and Ct. Wi as well as suppressed MS and BFR/BS as compared to controls. With PTH(1-84), bone turnover and bone mineral density increased in the lumbar spine. Requirements for calcium and vitamin D fell while serum and urinary calcium concentrations did not change. Conclusion Abnormal microstructure of the skeleton in hypoparathyroidism reflects the absence of PTH. Replacement therapy with PTH has the potential to correct these abnormalities as well as to reduce the requirements for calcium and vitamin D. PMID:20485912

  18. A histochemical and X-ray microanalysis study of calcium changes in insect flight muscle degeneration in Solenopsis, the queen fire ant

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.G.; Davis, W.L.; Vinson, S.B.

    1982-04-01

    Potassium pyroantimonate histochemistry, coupled with ethyleneglycoltetraacetic acid (EGTA)-chelation and X-ray microprobe analysis, was employed to localize intracellular calcium binding sites in the normal and degenerating flight musculature in queens of Solenopsis, the fire ant. In normal animals, calcium distribution was light to moderate within myofibrils and mitochondria. In the early contracture stages of the insemination-induced degeneration, both myofilament and mitochondrial calcium loading was markedly increased. In the terminal stages of myofibril breakdown, only Z-lines (isolated or in clusters) with an associated filamentous residue persisted. These complexes were also intensely calcium positive. This study further documents the presence of increased sarcoplasmic calcium during muscle necrosis. Surface membrane defects, mitochondrial calcium overload, and calcium-activated proteases may all be involved in this ''normal'' breakdown process.

  19. A calcium channel mutant mouse model of hypokalemic periodic paralysis

    OpenAIRE

    Wu, Fenfen; Mi, Wentao; Hernández-Ochoa, Erick O.; Burns, Dennis K.; Fu, Yu; Gray, Hillery F; Struyk, Arie F.; Martin F Schneider; Cannon, Stephen C.

    2012-01-01

    Hypokalemic periodic paralysis (HypoPP) is a familial skeletal muscle disorder that presents with recurrent episodes of severe weakness lasting hours to days associated with reduced serum potassium (K+). HypoPP is genetically heterogeneous, with missense mutations of a calcium channel (CaV1.1) or a sodium channel (NaV1.4) accounting for 60% and 20% of cases, respectively. The mechanistic link between CaV1.1 mutations and the ictal loss of muscle excitability during an attack of weakness in Hy...

  20. Potassium ferrate treatment of RFETS` contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-01

    The potassium ferrate treatment study of Rocky Flats Environmental Technology Site (RFETS) groundwater was performed under the Sitewide Treatability Studies Program (STSP). This study was undertaken to determine the effectiveness of potassium ferrate in a water treatment system to remove the contaminants of concern (COCS) from groundwater at the RFETS. Potassium ferrate is a simple salt where the iron is in the plus six valence state. It is the iron at the plus six valence state (Fe {sup +6}) that makes it an unique water treatment chemical, especially in waters where the pH is greater than seven. In basic solutions where the solubility of the oxides/hydroxides of many of the COCs is low, solids are formed as the pH is raised. By using ferrate these solids are agglomerated so they can be effectively removed by sedimentation in conventional water treatment equipment. The objective of this study was to determine the quality of water after treatment with potassium ferrate and to determine if the Colorado Water Quality Control Commission (CWQCC) discharge limits for the COCs listed in Table 1.0-1 could be met. Radionuclides in the groundwater were of special concern.

  1. Tradescantia-micronucleus test on potassium dichromate

    OpenAIRE

    Rafael Villalobos; Sandra Gómez; Ana Rosa Flores; Adriana Cisneros

    1986-01-01

    Cuttings with inflorescences of Tradescantia clone 4430 were allowed to absorb severa1 different concentrations of potassium dichromate during 6 hours and analysed 30 hours Jater. The frequencies of micronuclei (MCNs) in tetrads were more than twice those of the control. The relationship concentration-frequency was asymptotic.

  2. Genetics Home Reference: potassium-aggravated myotonia

    Science.gov (United States)

    ... structure and function of sodium channels. The altered channels cannot properly regulate ion flow, increasing the movement of sodium ions into ... area? Other Names for This Condition PAM sodium channel ... and Rare Diseases Information Center (1 link) Potassium aggravated myotonia Additional ...

  3. Hg0 absorption in potassium persulfate solution

    Institute of Scientific and Technical Information of China (English)

    YE Qun-feng; WANG Cheng-yun; WANG Da-hui; SUN Guan; XU Xin-hua

    2006-01-01

    The aqueous phase oxidation of gaseous elemental mercury (Hg0) by potassium persulfate (KPS) catalyzed by Ag+was investigated using a glass bubble column reactor. Concentration of gaseous mercury and potassium persulfate were measured by cold vapor atom absorption (CVAA) and ion chromatograph (IC), respectively. The effects of pH value, concentration of potassium persulfate and silver nitrate (SN), temperature, Hg0 concentration in the reactor inlet and tertiary butanol (TBA), free radical scavenger, on the removal efficiency of Hg0 were studied. The results showed that the removal efficiency of Hg0 increased with increasing concentration of potassium persulfate and silver nitrate, while temperature and TBA were negatively effective. Furthermore, the removal efficiency of Hg0 was much better in neutral solution than in both acidic and alkaline solution. But the influence of pH was almost eliminated by adding AgNO3. High Hg0 concentration has positive effect. The possible reaction mechanism of gaseous mercury was also discussed.

  4. 75 FR 23298 - Potassium Permanganate From China

    Science.gov (United States)

    2010-05-03

    ... from China (49 FR 3897). Following first five-year reviews by Commerce and the Commission, effective... permanganate from China (64 FR 66166). Following second five-year reviews by Commerce and the Commission... potassium permanganate from China (70 FR 35630). The Commission is now conducting a third review...

  5. Organogels Derived from Potassium 8-Nitroquinolinecarboxylate

    Institute of Scientific and Technical Information of China (English)

    HU,Hai-Yu; YANG,Yong; XIANG,Jun-Feng; CHEN,Chuan-Feng

    2007-01-01

    A new class of organogels derived from potassium 8-nitroquinoline-2-carboxylate was selectively formed in (V∶ V= 1∶ 1) THF/MeOH, and their superstructures were characterized by atomic force microscopy, scanning electron microscopy and transmission electron microscopy.

  6. Spectrophotometric Determination of Losartan Potassium in Tablets

    Directory of Open Access Journals (Sweden)

    Arianne Diane A. Aniñon

    2014-06-01

    Full Text Available In the quality control of pharmaceutical products, it is of utmost importance that validated analytical methods are used to ensure the credibility of the results generated. At the time of the study, official monographs from the United States Pharmacopeia and National Formulary (USP-NF for the quantification of Losartan potassium in tablets were unavailable, denoting the need for a validated analytical procedure for the analysis of the drug. The study adapted direct and first-derivative UV spectrophotometry methods proposed by Bonfilio and others (2010 for the assay of Losartan potassium in Losartan 50 mg. capsules, then modified and validated the said procedures for the assay of Losartan potassium in Losartan 100 mg. tablets following the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH guidelines on method validation for accuracy, precision, specificity, linearity, limit of detection, and limit of quantitation. Results demonstrated that all the performance characteristics of both methods were highly satisfactory and confirmed the possible application of the methods in routine analysis of Losartan potassium tablets.

  7. 21 CFR 582.3616 - Potassium bisulfite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium bisulfite. 582.3616 Section 582.3616 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  8. 21 CFR 582.3637 - Potassium metabisulfite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium metabisulfite. 582.3637 Section 582.3637 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  9. 21 CFR 182.3637 - Potassium metabisulfite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium metabisulfite. 182.3637 Section 182.3637 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  10. 21 CFR 182.3616 - Potassium bisulfite.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium bisulfite. 182.3616 Section 182.3616 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  11. Interactions between bicarbonate, potassium, and magnesium, and sulfur-dependent induction of luminescence in Vibrio fischeri.

    Science.gov (United States)

    Tabei, Yosuke; Era, Mariko; Ogawa, Akane; Morita, Hiroshi

    2012-06-01

    In spite of its central importance in research efforts, the relationship between seawater compounds and bacterial luminescence has not previously been investigated in detail. Thus, in this study, we investigated the effect of cations (Na(+) , K(+) , NH(4) (+) , Mg(2+) , and Ca(2+) ) and anions (Cl(-) , HCO(3) (-) , CO(3) (2-) , and NO(3) (-) ) on the induction of both inorganic (sulfate, sulfite, and thiosulfate) and organic (L-cysteine and L-cystine) sulfur-dependent luminescence in Vibrio fischeri. We found that HCO(3) (-) (bicarbonate) and CO(3) (2-) (carbonate), in the form of various compounds, had a stimulatory effect on sulfur-dependent luminescence. The luminescence induced by bicarbonate was further promoted by the addition of magnesium. Potassium also increased sulfur-dependent luminescence when sulfate or thiosulfate was supplied as the sole sulfur source, but not when sulfite, L-cysteine, or L-cystine was supplied. The positive effect of potassium was accelerated by the addition of magnesium and/or calcium. Furthermore, the additional supply of magnesium improved the induction of sulfite- or L-cysteine-dependent luminescence, but not the l-cystine-dependent type. These results suggest that sulfur-dependent luminescence of V. fischeri under nutrient-starved conditions is mainly controlled by bicarbonate, carbonate, and potassium. In addition, our results indicate that an additional supply of magnesium is effective for increasing V. fischeri luminescence.

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  14. [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

  15. Potassium-oxygen interactions on a Ru(001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Hrbek, J.; Shek, M.L.; Xu, G.Q. (Brookhaven National Lab., Upton, NY (United States)); Sham, T.K. (Univ. of Western Ontario, London, Ontario (Canada))

    1992-10-01

    The interaction of potassium with oxygen has been examined using synchrotron-based photoemission and NEXAFS, thermal desorption, work function measurements, and isotope exchange. Potassium coverages on Ru(001) surface ranging from monolayer to multilayer were investigated. Oxygen coadsorbed with potassium at 80 K forms a potassium-dioxygen complex, where both peroxide and superoxide ions were identified. The complex has high thermal stability on the Ru(001) surface, decomposing and desorbing at T > 900 K. 52 refs., 14 figs., 2 tabs.

  16. Educating My Replacement

    Science.gov (United States)

    Tarter, Jill

    , in partnership with the dedicated teachers out there, I think I can help promote the critical thinking skills and scientific literacy of the next generation of voters. Hopefully, I can also help train my replacement to be a better scientist, capable of seizing all the opportunities generated by advances in technology and our improved understanding of the universe to craft search strategies with greater probability of success than those I have initiated.

  17. Determinants of renal potassium excretion in critically ill patients : The role of insulin therapy

    NARCIS (Netherlands)

    Hoekstra, Miriam; Yeh, Lu; Lansink, Annemieke Oude; Vogelzang, Mathijs; Stegeman, Coen A.; Rodgers, Michael G. G.; van der Horst, Iwan C. C.; Wietasch, Gotz; Zijlstra, Felix; Nijsten, Maarten W. N.

    2012-01-01

    Objectives: Insulin administration lowers plasma potassium concentration by augmenting intracellular uptake of potassium. The effect of insulin administration on renal potassium excretion is unclear. Some studies suggest that insulin has an antikaliuretic effect although plasma potassium levels were

  18. Determinants of renal potassium excretion in critically ill patients : The role of insulin therapy

    NARCIS (Netherlands)

    Hoekstra, Miriam; Yeh, Lu; Oude Lansink, Annemieke; Vogelzang, Mathijs; Stegeman, Coen A.; Rodgers, Michael G. G.; van der Horst, Iwan C. C.; Wietasch, Gotz; Zijlstra, Felix; Nijsten, Maarten W. N.

    Objectives: Insulin administration lowers plasma potassium concentration by augmenting intracellular uptake of potassium. The effect of insulin administration on renal potassium excretion is unclear. Some studies suggest that insulin has an antikaliuretic effect although plasma potassium levels were

  19. [Ascending aorta replacement late after aortic valve replacement].

    Science.gov (United States)

    Hayashi, Yasunari; Ito, Toshiaki; Maekawa, Atsuo; Sawaki, Sadanari; Fujii, Genyo; Hoshino, Satoshi; Tokoro, Masayoshi; Yanagisawa, Junji

    2013-07-01

    Replacement of the asceding aorta is indicated in patients undergoing aortic valve replacement( AVR), if the diameter of the ascending aorta is greater than 5.0 cm. If the diameter of the asceding aorta is from 4.0 to 5.0 cm, it was arguable whether replacement of the ascending aorta should be performed. Nine patients who underwent reoperative ascending aorta replacement after AVR were reviewed retrospectively. Reoperation on the asending aorta replacement was performed 11.8±7.2 years (range 1y5m~23y3m) after AVR. Mean patient age was 69.9±6.3 (range 60~81). In 2 cases, reoperations were performed early year after AVR. Although ascending aorta was dilated at the 1st operation, replacement wasn't performed for the age and minimally invasive cardiac surgery (MICS). In 3 cases, reoperations were performed more than 10 years later. On these cases, ascending aorta aneurysm and dissection occurred with no pain and were pointed out by computed tomography(CT) or ultrasonic cardiogram(UCG). We think that patients with dilatation of the ascending aorta should undergo AVR and aorta replacement at the 1st operation regardness of age. It is important that patients who underwent AVR should undergo a regular checkup on the ascending aorta.

  20. Effect of background potassium channels on potassium homeostasis in healthy and epileptic hippocampus

    OpenAIRE

    Päsler, Dennis

    2015-01-01

    In the frequent neurological disease of epilepsy, focal extracellular potassium concentration in the brain increases to pathological values. The underlying mechanisms are not yet fully understood. Two-pore-domain potassium channels (K2P channels), postulated in the 1950s and cloned and investigated in the past years, came into scientific view. A contribution of these channels on keeping membrane’s resting potential of glial cells is proven. In the present study, the contribution of K2P channe...