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Assessment of the NMR visibility of intraerythrocytic sodium by flame photometric and ion‐competitive studies
Author(s) -
Nissen Henrik,
Jacobsen Jens Peter,
Hørder Mogens
Publication year - 1989
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910100310
Subject(s) - sodium , chemistry , isotopes of sodium , ion , analytical chemistry (journal) , visibility , proton nmr , relaxation (psychology) , nuclear magnetic resonance , chromatography , stereochemistry , physics , organic chemistry , optics , medicine
23 Na nuclear magnetic resonance (NMR) studies of intraerythrocytic sodium concentrations were performed at 37°C and the accuracy of the method was evaluated through concomitant emission flame photometric analysis. NMR visibility of intraerythrocytic sodium was estimated to be 75 ± 3%. Verification of the presence of an NMR invisible intraerythrocytic sodium pool and assessment of the mechanisms explaining this invisibility was achieved by measurement of 23 Na NMR signal intensities and T 1 relaxation times of erythrocyte hemolysate during ion‐competitive sodium release from association sites. Signal intensities after addition of small quantities of K + and Mg 2+ to the hemolysates were significantly larger than that expected from dilution of the sample, implying that the additions have resulted in the release of formerly invisible sodium. Furthermore, the intensities following the addition of K + were significantly larger than those after the addition of Li + and choline + . This signifies a specificity of the association sites at which sodium has decreased visibility. Increased T 1 values following the additions confirmed the release of bound sodium. © 1989 Academic Press, Inc.