A simple precipitation method for measuring sialic acid in apolipoprotein B-containing lipoproteins in plasma.
BACKGROUND
A convenient method for the measurement of sialic acid in plasma apoB-containing lipoproteins is described.


METHODS
Dextran sulphate-Mg(2+) precipitation and enzymatic sialic acid assay were combined and applied to analysis of plasma from 96 healthy controls and 136 hyperlipidaemic subjects of types IIa (n=46), IIb (n=43), and IV (n=47).


RESULTS
The sialic acid concentrations (mean+/-SD) in plasma apoB-containing lipoproteins were 19.4+/-5.9, 24.3+/-4.7 (P<0.0001 versus normal), 23.0+/-4.7 (P<0.0001), 27.9+/-5.2 (P<0.0001), and 22.3+/-3.4 mg/L (P<0.002), for normal, all types of hyperlipidaemia, types IIa, IIb, and IV, respectively. The contents of sialic acid in apoB were 2.03+/-0.41%, 2.09+/-0.35% (no significance versus normal), 1.86+/-0.27% (P<0.0001), 1.97+/-0.26% (P<0.02), and 2.28+/-0.41% (P<0.002), for normal, all types of hyperlipidaemia, types IIa, IIb, and IV, respectively.


CONCLUSIONS
The content of sialic acid in apoB decreased significantly in type IIa but increased in type IV hyperlipidaemia, which may reflect the presence of sialic acid in very low-density lipoprotein apolipoproteins other than apoB. This simple precipitation method will be useful to evaluate the sialic acid content in low-density lipoprotein in hyperlipidaemic subjects, especially of type IIa.
Central Laboratory Department, Ehime University School of Medicine, Toon City, 791-0295, Ehime Prefecture, Japan. kshishi@m.ehime-u.ac.jp
Koji
K
Shishino
Yuki
Y
Yoshioka
Kaori
K
Hashimoto
Masaaki
M
Ochi
Kenji
K
Aono
Mitsuharu
M
Murase
Haruhiko
H
Osawa
Hideichi
H
Makino
Shuichi
S
Saheki
D000328:Adult; D001055:Apolipoproteins B / Q000737:chemistry*; D011232:Chemical Precipitation; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood; D008297:Male; D008875:Middle Aged; D019158:N-Acetylneuraminic Acid / Q000032:analysis* / Q000097:blood*; D012680:Sensitivity and Specificity
D001055:Apolipoproteins B; D019158:N-Acetylneuraminic Acid