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  • Polymer and Materials Science  (6)
  • sodium excretion
  • squid axon
  • 1985-1989  (9)
  • 1890-1899
  • 1
    Electronic Resource
    Electronic Resource
    Effects of fatty acids on membrane currents in the squid giant axon (1987)
    Springer
    The journal of membrane biology 95 (1987), S. 113-120 
    Details
    ISSN: 1432-1424
    Keywords: fatty acids ; membrane currents ; membrane excitation ; 2-decenoic acid ; lateral motion ; squid axon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The effects of fatty acids on the ionic currents of the voltage-clamped squid giant axon were investigated using intracellular and extracellular application of the test substances. Fatty acids mainly suppress the Na current but have little effect on the K current. These effects are completely reversed after washing with control solution. The concentrations required to suppress the peak inward current by 50% and Hill number were determined for each fatty acid. ED50 decreased about 1/3 for each increase of one carbon atom. The standard free energy was −3.05 kJ mole−1 for CH2. The Hill number was 1.58 for 2-decenoic acid. The suppression effect of the fatty acids depends on the number of carbon atoms in the compounds and their chemical structure. Suppression of the Na current was clearly observed when the number of carbon atoms exceeded eight. When fatty acids of the same chain length were compared, 2-decenoic acid had strong inhibitory activity, but sebacic acid had no effect at all on the Na channel. The currents were fitted to equations similar to those proposed by Hodgkin and Huxley (J. Physiol. (London) 117:500–544, 1952) and the changes in the parameters of these equations in the presence of fatty acids were calculated. The curve of the steady-state activation parameter (m ∞) for the Na current against membrane potential and the time constant of activation ({ie113-1}) were shifted 20 mV in a depolarizing direction by the application of fatty acids. The time constant for inactivation ({ie113-2}) was almost no change by application of the fatty acids. The time constant for activation ({ie113-3}) of K current was shifted 20 mV in a depolarizing direction by the application of the fatty acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01869156
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of arachidonic acid and the other long-chain fatty acids on the membrane currents in the squid giant axon (1988)
    Springer
    The journal of membrane biology 106 (1988), S. 141-147 
    Details
    ISSN: 1432-1424
    Keywords: arachidonic acid ; long-chain fatty acids ; membrane currents ; Na channel ; squid axon ; membrane excitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The effects of arachidonic acid and some other long-chain fatty acids on the ionic currents of the voltage-clamped squid giant axon were investigated using intracellular application of the test substances. The effects of these acids, which are usually insoluble in solution, were examined by using α-cyclodextrin as a solvent. α-cyclodextrin itself had no effect on the excitable membrane. Arachidonic acid mainly suppresses the Na current but has little effect on the K current. These effects are completely reversed after washing with control solution. The concentration required to suppress the peak inward current by 50% (ED50) was 0.18mm, which was 10 times larger than that of medium-chain fatty acids like 2-decenoic acid. The Hill number was 1.5 for arachidonic acid, which is almost the same value as for medium-chain fatty acids. This means that the mechanisms of the inhibition are similar in both long- and medium-chain fatty acids. When the long-chain fatty acids were compared, the efficacy of suppression of Na current was about the same value for arachidonic acid, docosatetraenoic acid and docosahexaenoic acid. The suppression effects of linoleic acid and linolenic acid on Na currents were one-third of that of arachidonic acid. Oleic acid had a small suppression effect and stearic acid had almost no effect on the Na current. The currents were fitted to equations similar to those proposed by Hodgkin and Huxley (Hodgkin, A.L., Huxley, A.F. (1952)J. Physiol (London) 117:500–544) and the change in the parameters of these equations in the presence of fatty acids were calculated. The curve of the steady-state activation parameter (m ∞) for the Na current against membrane potential and the time constant of activation (τ m ) were shifted 10 mV in a depolarizing direction by the application of fatty acids. The time constant for inactivation (τ h ) has almost unaffected by application of these fatty acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01871396
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  • 3
    Electronic Resource
    Electronic Resource
    A Quantitative Method of Evaluating the Diuretic Response to Furosemide in Rats (1988)
    Springer
    Pharmaceutical research 5 (1988), S. 694-698 
    Details
    ISSN: 1573-904X
    Keywords: furosemide ; diuresis ; sodium excretion ; potassium excretion ; chloride excretion ; urinary excretion rate ; urinary electrolytes in rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Furosemide effects are usually evaluated by measuring the urinary excretion rate of Na+ (UVNa) in humans. In the present study, however, UVNa showed a nonlinear relationship with urine flow rate after intravenous injection of furosemide in rats. In contrast, when the urinary excretion rate of (Na+ + K+) (UVNa+K) was plotted against the urine flow rate, a linear regression line was observed, with small interindividual variations in normal rats and in rats with uranyl nitrate-induced acute renal failure (ARF). Piretanide, a loop diuretic, also showed a similar relationship, while other types of diuretics revealed different slope values for the relationship. Although the urinary excretion rate of Cl− (UVC1) vs UVNa+K is expected to show a linear relationship in normal rats, the correlation coefficient of the linear regression line was smaller than that of the urine flow rate vs UVNa+K. Further, the slope of UVC1 vs UVNa+K was slightly different in ARF rats. Therefore, UVNa+K provides a better quantitative measure of diuretic response to loop diuretics than UVNa or UVC1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015999626133
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  • 4
    Electronic Resource
    Electronic Resource
    Structural and energetic parameters of Ca2+ binding to peptides and proteins (1988)
    New York : Wiley-Blackwell
    Biopolymers 27 (1988), S. 1865-1886 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characteristics of Ca2+-binding sites and of the structural reorganization induced by Ca2+-binding in storage proteins and ion carriers are being studied as models for molecular mechanisms in Ca2+ channels and in Ca2+-dependent modulatory proteins. A first step in the study was the development of energy parameters for Ca2+ compatible with those in the CHARMM package of computer simulation software. Such parameters were obtained from an analytical fit to the potential surface for [(Ca)(OCH2)4]2+ calculated with an ab initio molecular orbital method. The resulting parametrization was tested for the hexapeptide cyclo-(Pro-Gly)3, and a 75 residue long calcium binding protein from bovine intestine (ICaBP). The geometrical parameters calculated for the hexapeptide and its 2:1 complex with Ca2+ were in good agreement with experimental data from crystallography and nmr. Similarly, the structure of ICaBP optimized with CHARMM using the new Ca2+ parameters showed good agreement with the x-ray structure both in the local structures of the calcium-binding sites and in the overall shape of the protein.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360271202
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  • 5
    Electronic Resource
    Electronic Resource
    Electron transfer function of kerateine gel and conjugated redox reaction by using the kerateine-immobilized membrane (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 2883-2895 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kerateine gel, prepared by reducing wool keratin with alkaline 2-mercaptoethanol-urea solution and by partially reoxidizing the dissolved kerateine, reduced iron(III) to iron(II). Reduction of iron(III) was enhanced by addition of copper(II). Reduction of methylene blue (MB) to leuco MB with thioglycollic acid (TGA) as a model compound of wool thiol group was investigated in the presence of copper(II) and intercuticular cementing material (δCu) extracted from wool fiber. It is confirmed that copper(II) is a catalyst for the reduction of MB and the δCu containing copper ion acts as a carrier for electron transfer.Some kerateine/δCu-immobilized hydrophilic polyurethane membranes were prepared. A conjugated redox reaction combining the reduction of MB and the oxidation of TGA was carried out across these membranes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080270905
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  • 6
    Electronic Resource
    Electronic Resource
    Ionic products in ground polymer. IV. Anions in poly(vinylidene fluoride) (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1307-1312 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When poly(vinylidene fluoride) (PVDF) was ground with tetracyanoethylene (TCNE) powder in a vibration glass ball mill in vacuum in the dark at 77 K, the TCNE anion radical (TCNE-) was detected in the mixture by ESR spectroscopy. The TCNE.- is formed by the abstraction of electrons by TCNE from the anion that is produced by a heterogeneous bond scission of carbon-carbon bonds in the polymer main chain. The assignment of TCNE.- was carried out by the ESR spectral simulation on the basis of an anisotropic effective hyperfine tensor that includes a forbidden transition term. At least 85% of the bond scission of the PVDF main chain is induced by a heterogeneous process to produce ionic products. The yield of these mechanions seems to increase with the polarity of carbon-carbon bond owing to a substituent group bonded to the carbon in the polymer main chain.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260614
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  • 7
    Electronic Resource
    Electronic Resource
    Ionic species produced by mechanical fracture of solid polymer. III. Anions from polytetrafluoroethylene (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 1431-1437 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The tetracyanoethylene anion radical (\documentclass{article}\pagestyle{empty}\begin{document}${\rm TCNE}^{ \cdot ^ - } $\end{document}) was detected by ESR spectroscopy in polytetrafluoroethylene (PTFE), which had been mechanically fractured in vacuo with tetracyanoethylene (TCNE) at 77 K. The assignment of \documentclass{article}\pagestyle{empty}\begin{document}${\rm TCNE}^{ \cdot ^ - } $\end{document} was carried out by ESR spectral simulation on the basis of an anisotropic effective hyperfine tensor that included a forbidden transition term. The \documentclass{article}\pagestyle{empty}\begin{document}${\rm TCNE}^{ \cdot ^ - } $\end{document} is formed by abstraction of an electron by TCNE from the anion that is produced by heterogeneous scission of the carbon-carbon bond in the main chain of PTFE. At least 16% of the scission of the main chains of PTFE occurs by a heterogeneous process to produce the anions. Approximately 50% of the anions decay during annealing for 30 min at 220 K in the dark, and all anions decay within 15 min at 325 K.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1987.090250706
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of pore size of porous bead carriers immobilizing antibody on IgE adsorption (1986)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 20 (1986), S. 853-858 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Immunoglobulin E (IgE) adsorption was studied using antihuman IgE antibody immobilized on alkylamine glass carriers with different pore sizes (Controlled Pore Glass [CPG]®) to determine the effect of pore size on IgE adsorption in therapeutic immuno-adsorbents. With a series of CPGs whose pore sizes were in the range of 170 to 1400 Å, CPGs possessing pore sizes larger than 500 Å had higher IgE adsorption. A CPG (500-Å pore size) with the spacer arm 20 Å long did not give better IgE removal than CPG without the spacer arm, since the spacer prevented the immobilization of a sufficient amount of the antibody on the carrier because of steric hindrance. However, the antibodies, once immobilized on CPG with the spacer arm, bound the same amount of IgE molecules (antigens) as those immobilized on CPG without the spacer arm.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820200615
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  • 9
    Electronic Resource
    Electronic Resource
    On the adhesion between Hydroxyl-Terminated Polybutadiene Fuel-Binder and Ammonium Perchlorate. Performance of bonding agents (1985)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 10 (1985), S. 176-180 
    Details
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple method to evaluate the adhesive force between solid oxidizer and polymeric fuel-binder is presented. As an illustration, hydroxyl-terminated polybutadiene (HTPB) sticks including several different bonding agents are bonded on ammonium perchlorate (AP) single crystals, and stress-strain history until rupture occurs is obtained by applying uniaxial tensile stress perpendicularly to the adhesion surface. Further, whether each bonding agent reacts with AP or not was analysed with pursuing infrared absorption spectra. The hypothesis that the interfacial adhesive force arises from hydrogen bonding force is proposed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19850100604
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