Determination of ionized magnesium in platelets and correlation with selected variables.
We describe a method for determining the intracellular ionized magnesium concentration ([Mg2+]i) in platelets by using the fluorescent probe FURAPTRA. We determined the dissociation constant (KD) of FURAPTRA for Mg2+ (2.26 +/- 0.29 mmol/L), within-day assay variability (CV = 6.8%), among-day intraindividual variability (CV = 11.0%), variability after a 4-h delay in processing the blood specimen (t = 1.2, P >0.2; F = 6.2, P <0.02), and the reference interval (0.23-0.59 mmol/L) for this assay. We also evaluated the correlation between platelet [Mg2+]i and concentrations of selected serum electrolytes, proteins, and total cholesterol; age; body mass index; and gender. Only the inverse correlation between platelet [Mg2+]i and serum total cholesterol concentration in men was significant (r=-0.66, P <0.005).
Niemela
J E
JE
Clinical Pathology Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
Snader
B M
BM
Elin
R J
RJ
D000328:Adult; D000375:Aging; D001792:Blood Platelets / Q000737:chemistry*; D015992:Body Mass Index; D002413:Cations, Divalent; D004573:Electrolytes / Q000097:blood; D005260:Female; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives*; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012680:Sensitivity and Specificity
D002413:Cations, Divalent; D004573:Electrolytes; D005456:Fluorescent Dyes; C058776:2-(2-(5-carboxy)oxazole)-5-hydroxy-6-aminobenzofuran-N,N,O-triacetic acid; D008274:Magnesium; D016257:Fura-2