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.

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Xanthoma is a common complication of familial hypercholesterolemia and has been considered to be associated with atherosclerotic state, especially coronary heart disease. (CAD)
Although the patients with xanthoma investigated in this study had also high frequency of occurence of coronary artery disease in general agreement with the previous reports, some patients were not associated with coronary artery disease even if their xanthoma were quite severe. The purpose of this study is to define the relationship between the type of xanthoma or lipoprotein abnormalities and prevalence of coronary artery disease, and further to clarify the major factor of the development of atherosclerosis.
42 patients with xanthoma in our clinic were devided into 4 groups according to patterns of xanthoma:
Group (1): Xanthelasma alone
Group (2): Achilles tendon xanthoma alone
Group (3): Achilles tendon xanthoma with xanthelasma
Group (4): Tuberous xanthoma and/or cutaneous xanthoma
The levels of lipids and lipoproteins in serum of each groups were detected and comparired between each other.
Patients in group (1) had lower levels of cholesterol (chol.) and lower frequency of CAD than those of group (2), (3) and (4). Group (2), (3) and (4) had similar frequencies of CAD which was more than 50%.
HDL-chol. was significantly lower levels in patients with CAD than in those without CAD, but there were no significant differences in levels of chol, and triglyceride between those with CAD and without CAD.
The lower the HDL-chol, levels, the higher the frequencies of CAD, on the contrary, there were no CAD patients with HDL-chol. level for more than 50mg/dl. The higher Atherogenic Index (VLDL+LDL/HDL), the higher frequency of CAD.
Achilles tendon was significantly thicker in patients with CAD than in those without CAD, and the thicker Achilles tendon the patients had, the higher freequency of CAD they had.

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