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  • 1
    ISSN: 1435-1803
    Keywords: Free radicals ; spin trapping ; infarct size ; reperfusion injury ; ischemic cell death
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ischemic, reperfused porcine hearts were used to investigate whether the spin trap agent PBN (N-tert-butyl-alpha-phenylnitrone) attenuates postischemic cell death by scavenging of free radicals. The left anterior descending coronary artery (LAD) was ligated distally in 16 pigs for 45 min and then reperfused for 3 h. PBN (coronary concentration approximately 1 mM) was infused into the LAD of eight pigs during the first 45 min of reperfusion. Electron spin resonance spectroscopy (ESR) was performed to identify free radical adducts in the reperfused coronary venous blood. Regional systolic shortening (SS%) was determined by sonomicrometry. Infarct size was evaluated as the percentage of infarcted (tetrazolium stain) to ischemic (dye technique) myocardium. The transmural ultrastructural degree of myocardial injury as well as myocardial ATP levels were assessed at the end of the experiment. Intracoronary treatment with PBN during early reperfusion did not attenuate myocardial damage. Infarct sizes (control group 59±19%, treated group 55±14%), transmural ultrastructural alterations, myocardial ATP concentrations (control group 1.8±0.3 μmol/mg frozen weight, treated group 1.7±0.4 μmol/mg) and regional systolic shortening at the end of the experiments (control group −1±5%, treated group −2±6% did not differ significantly. Furthermore, under various experimental conditions of spin trapping, free radical adducts could not be identified in coronary venous blood during early reperfusion. The results suggest that the spin trap agent PBN (1 mM) does not affect postischemic cell death in porcine hearts.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The lifetime of cation selective carrier-PVC-membranes partially depends on the components' remaining in the membrane. An exchange of monomeric by polymeric plasticizers with low tendency to migrate lengthens the function time drastically. Other than for Na+ - and NH4+-selective membranes, it is essential for K+ - and Ca2+-selective membranes and optional for H+-selective membranes to incorporate lipophilic anions in order to make the phase transfer catalysis more efficient. The resistence to saponification of phthalic acid polyester gives H+-selective membranes a high stability of measured values even in the alkaline range.For anion selective PVC-membranes, instead of cation selective plasticizers the plasticizing qualities of a liquid charged ligand should be used.The tubular carrier-PVC-membranes of our ion selective flow through measuring systems are diffusion welded to the ends of two PVC-tubes [1] so that they are absolutely tight with no risk of potential leakage. Migration of the membrane components plasticizer and ionophore across this border as well as their extraction [2, 3] into the measuring solution [4] will naturally reduce the membrane's functionning time [5].
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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