title: Clinical application of sodium-23 nuclear magnetic resonance for measurement of red cell sodium concentrations.
abstract: Red cell sodium (RBC-Na+) concentrations were measured using 23Na nuclear magnetic resonance (NMR), without the destruction of erythrocyte membranes. Subjects were categorized into four groups: 20 normotensive subjects (NT group), 20 age-matched essential hypertensive patients (EHT group), 10 patients with primary aldosteronism (PA group), and 18 patients treated with digoxin (DIG group). Although RBC-Na+ concentrations were similar between the NT group (6.14 +/- 0.80 (Mean +/- SD) mmol/l) and the EHT group (5.92 +/- 0.99), they were significantly higher in both the PA group (7.55 +/- 0.88, p less than 0.001) and the DIG group (8.43 +/- 3.81, p less than 0.02). In the PA group, RBC-Na+ concentrations decreased significantly after resection of the adenoma, and there was an inverse relationship between serum potassium and RBC-Na+ concentrations (r = -0.65, p less than 0.01). In the DIG group, RBC-Na+ concentrations tended to increase in proportion to serum digoxin levels (r = 0.53, p less than 0.05). These results support the view that RBC-Na+ concentrations are determined primarily by Na+/K+-pump activity of red cell membranes. This study showed also that Na+ NMR is an useful method determining intracellular Na+ concentrations.
authors.affiliation: Department of Medicine, National Cardiovascular Center Hospital, Osaka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kojima
authors.forename: M
authors.initials: M
authors.lastname: Kanashiro
authors.forename: F
authors.initials: F
authors.lastname: Hayashi
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: H
authors.initials: H
authors.lastname: Abe
authors.forename: M
authors.initials: M
authors.lastname: Imanishi
authors.forename: M
authors.initials: M
authors.lastname: Kawamura
authors.forename: Y
authors.initials: Y
authors.lastname: Kawano
authors.forename: T
authors.initials: T
authors.lastname: Ashida
authors.forename: G
authors.initials: G
authors.lastname: Kimura
mesh_terms: D004077:Digoxin / Q000097:blood; D004912:Erythrocytes / Q000032:analysis*; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood; D006973:Hypertension / Q000097:blood; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011188:Potassium / Q000097:blood; D012964:Sodium / Q000097:blood*
chemical_list: D004077:Digoxin; D012964:Sodium; D011188:Potassium