1981 Volume 18 Issue 4 Pages 247-255
This report describes a method for and the result of the analysis of cholesterol and phospholipids in HDL2 and HDL3, and of phospholipids in VHDL (d.>1.210).
After precipitating and eliminating LDL (low density lipoprotein) and VLDL (very low density lipoprotein) by Na. phosphotangstate and MgCl2 and bringing the non-protein density to 1.125, the serum was subjected to ultracentrifugation in #494 angle rotor of IEC/B-60 ultracentrifuge (Kubota-International) at 105, 000×G for 22 hours.
Dividing then the sample into four fractions from the top to the bottom layers, A1 (0.5ml), A2 (1.0ml), B (2.0ml) and C (remaining solution), the cholesterol and phospholipids were determined in these 4 fractions.
After bringing the non-protein density of fraction C to 1.210, the ultracentrifugation was repeated under the same condition and the cholesterol and phospholipids in the top fraction (C1 0.5ml) were determined.
The conditions under which the first ultracentrifugation was performed proved inadequate in separation between HDL2 and HDL3 at the clear zone beneath the top of fraction (A2). Therefore, the HDL2/HDL3 ratio in this mixed zone (A2) was obtained by calculation based on the phospholipids/cholesterol ratio, in consideration of the latter ratio being substantially and constantly different between HDL2 and HDL3 (HDL2<HDL3).
The phospholipids/cholesterol ratio of HDL2 was derived from the phospholipid and cholesterol concentrations of fraction A1 and that of HDL3, from those of fraction C1 respectively.
The VLDL-phospholipids were calculated by subtracting the HDL3-phospholipids from the phospholipids in fractions of density exceeding 1.125 (fractions B and C)
The HDL2 cholesterol and phospholipids were 15.5±4.3 and 21.9±5.9mg/dl in five normal men, and 18.6±5.9 and 28.0±8.1mg/dl in five normal women respectively. The HDL3-cholesterol and phospholipids were 39.4±5.2 and 60.6±8.2mg/dl in normal men, and 44.1±12.1 and 72.3±22.0mg/dl in normal women respectively. The VHDL-phospholipids were 17.0±3.8mg/dl in normal men and 22.4±5.5mg/dl in normal women.
Both HDL2 and HDL3 cholesterol and phospholipids decreased in many patients with the cerebral thrombosis and myocardial infarction. Moreover, the VHDL-phospholipids significantly decreased in all the patients with the cerebral thromboses, while they decreased, on the contrary, only in 1 out of 4 myocardial infarction patients.
The HDL2 and HDL3 cholesterol and phospholipids were low in patients with diabetes mellitus, but their VHDL-phospholipids did not decrease.
The decrease of VHDL-phospholipids in cerebral thrombosis was due to the lowered lysolecithin level in the VLDL fraction.
