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  • 1
    Electronic Resource
    Electronic Resource
    FURTHER STUDIES ON THE K+-DEPENDENT SWELLING OF PRIMATE CEREBRAL CORTEX IN VIVO: THE ENZYMATIC BASIS OF THE K+-DEPENDENT TRANSPORT OF CHLORIDE (1972)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 19 (1972), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The swelling of intact, exposed primate cerebral cortex perfused in vioo under, isosmotic conditions was a linear function of the concentration of K+ in perfusate over the range 25–117 mM. The K+-dependent swelling was manifested throughout the depth of the cerebral cortex studied and was associated with an increased content of chloride in the swollen tissue, despite the constancy of the concentration of external chloride. The swelling of the cerebral cortex was a linear function of the temperature of the perfusate over the range 15–38°C, despite the constancy of the concentration of external K+. Moreover, the content of chloride in the swollen cerebral cortex was a linear function of the temperature of the overlying perfusate, despite the constancy of the external concentration of chloride. The changes in the contents of Na+ and K+ in the swollen cerebral cortex perfused with solutions containing constant concentrations of external Na+ and K+ but differing in temperature suggested that the fluid of swelling in the tissue was rich in both K+ and CI-, as had been shown previously in vitro. Perfusion of the exposed, intact cerebral cortex in uiuo with K+-rich fluids usually involved the reciprocal reduction of the concentrations of Na+ in the perfusate to maintain isotonicity. When comparable reductions in the concentration of external Na+ were achieved by replacement with choline (instead of K+), swelling of the perfused, exposed cortex was significantly less than that attributed to isotonic, K+-rich but Na+-poor fluids. These observations suggested that it was the elevated levels of K+ rather than lowered concentrations of Na+ that promoted the swelling of the perfused cerebral cortex.The apparent rate of influx of 36Cl from the perfusate into the underlying exposed and intact monkey cerebral cortex in vivo was a linear function of the concentration of K+ in perfusate over the range 25–117 mM and conformed to Michaelis-Menten kinetics when plotted according to Lineweaver and Burk. Moreover, the apparent influx of chloride from perfusate into swollen cerebral cortex was a linear function of the percentage swelling of cerebral cortex over the range 6–30 per cent. However, the apparent rate of influx of chloride from perfusate into unswollen cortex was not consistent with the linear correlation already described for swollen cerebral cortex. One reason for this discrepancy was the reduction in the size of the true (inulin) extracellular space associated with the K+-dependent swelling of cerebral cortex in vivo. The anatomical locus for this K+-dependent swelling of cerebral cortex was an expanded glial compartment, as demonstrated by electron-microscopy. The parenteral administration (50 mg/kg) or local perfusion (5 mM) of acetazolamide inhibited the K+-dependent swelling of cerebral cortex in vivo. Moreover, administration of acetazolamide inhibited the K+-dependent increase in content of C1- and the K+-dependent rate of influx of 36Cl into swollen cerebral cortex. We have discussed the possible enzymatic basis of these K+-dependent alterations in content of fluid and chloride and transport of chloride in mammalian cerebral cortex in viuo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1972.tb01383.x
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  • 2
    Electronic Resource
    Electronic Resource
    STUDIES ON THE SITE OF MEDIATED TRANSPORT OF CHLORIDE FROM BLOOD INTO CEREBROSPINAL FLUID: EFFECTS OF ACETAZOLAMIDE (1972)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 19 (1972), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— In monkeys we measured the steady-state concentrations of Cl− in endogenous CSF, in artificial CSF (which had equilibrated with the underlying exposed surface of the cerebral cortex but was not in diffusion equilibrium with endogenous CSF), and in arterial plasma. The ratio of the distribution of Cl− in artificial CSF to that in plasma was consistent with a passive Donnan distribution, whereas that ratio describing Cl− levels in endogenous CSF in comparison to those in plasma clearly exceeded theratio required for a passive, Donnan−type of distribution for Cl−. The kinetic analysis of the efflux of Cl− from blood into endogenous CSF and into artificial CSF (perfused over the exposed surface of the cerebral cortex) indicated that the rate of efflux of Cl− into endogenous CSF which was continuous with ventricular fluid was inhibited by acetazolamide [in confirmation of a similar finding described previously by Maren and Broder (1970)], whereas the rate of efflux of chloride from blood into the artificial CSF perfusate was uninfluenced by pretreatment of animals with acetazolamide. We have discussed the site of mediated (active) transport of chloride from blood into CSF in light of these findings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1972.tb01448.x
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  • 3
    Electronic Resource
    Electronic Resource
    Studies of the production and subsequent reduction of swelling in primate cerebral cortex under isosmotic conditionsin vivo (1970)
    Springer
    Experimental brain research 10 (1970), S. 427-446 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortexin vitro andin vivo ; Chloride transport ; Primate ; Cortical edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The swelling of intact primate cerebral cortex perfused under isosmotic conditionsin vivo, like swelling of slices of mammalian cerebral cortex incubatedin vitro, is a linear function of the concentration of K+ in the extracellular fluid over the range 20–120 mM. 2. The simultaneous presence of the Cl− ion is required for the development of K+-dependent swelling of cerebral cortex under various experimental conditionsin vivo andin vitro. 3. The maintenance of previously established K+-dependent swelling of cerebral cortex bothin vitro andin vivo requires the relative concentrations of both K+ and Cl− in the extracellular fluid to remain constant. A reduction in the concentration of either ion is associated with an absolute loss of fluid of swelling of cerebral cortex. 4. The content of Cl− in cerebral cortex is a function of the magnitude of K+-dependent swelling even though the concentration of Cl− in the extracellular fluid is maintained constant. 5. The mechanism of swelling in primate cerebral cortex following cerebral circulatory arrest is discussed in the light of the experimental findings, as a model of the type of brain injury encountered in massive clinical stroke.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02324768
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  • 4
    Electronic Resource
    Electronic Resource
    The pyrolytic characterization of a surfactant/polymer/ceramic composite system using combined thermogravimetric analysis-mass spectrometry (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 301-309 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An experimental technique of combined thermogravimetric analysis (TGA)-mass spectrometry (MS) was used to study the pyrolysis process during binder removal from a ceramic/binder system. The effect of a fluorocarbon surfactant on the pyrolysis process was also investigated and it was discovered that the surfactant had no significant effect on pyrolysis. A simple paraffin binder system was implemented so as to enhance the effects of the surfactant. The identification of the fragments created during pyrolysis is also discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070410122
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  • 5
    Electronic Resource
    Electronic Resource
    Solvent-induced crystallization in polyetherimide thermoplastics and their carbon fiber composites (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 1289-1296 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Solvent-induced crystallization (SINC) was observed in a polyetherimide (PEI), a thermoplastic used as a matrix in carbon fiber composites. This observation was made using wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), and optical microscopy. It was discovered that methylene chloride induces crystallization in the PEI by penetrating the surface and swelling the bulk polymer. Prepreg processed using N-methyl pyrrolidone (NMP) was also crystalline. One processed above the crystalline melting point (Tm), no crystallinity in the sample was found, as the PEI did not crystallize from the melt. The observed crystallization of both the neat polymer and its carbon fiber prepreg was exclusively through a solvent-induced process, although it is likely that the mechanism through which crystallization occurs during solvent prepreg processing is different than the diffusion-controlled mechanism demonstrated with methylene chloride. A solvent prepregging process may involve a low molecular weight or monomer solution as well as other polymerization by products. Measurements using WAXS showed a maximum degree of crystallinity of 30%, as induced by methylene chloride. A value of 85 J/g for the heat of solvent-induced crystallization in the PEI was calculated from the DSC measurements.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420512
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