476 V. BLOOD LIPIDS 



S f 10-20 occur. Molecules in the S f 3-8 class contain about 25% of pro- 

 tein, while the S f 10-20 class has little protein but 30% of cholesterol by 

 weight. 



In a study of a large number of normal men and women of widely dif- 

 ferent age groups, Gofman et a 7 . 96 found that the incidence of increased 

 concentration of S f 10-20 molecules was much more frequent in the "nor- 

 mal" males twenty to forty years of age than in the same female "normal" 

 age group. In the series of normals over forty, both males and females had 

 a definite increase in the S f 10-20 fraction over the levels in the correspond- 

 ing younger groups. These facts are in line with the incidence of athero- 

 sclerosis as related to age in the two sexes. All but 3 of 104 patients who 

 had previously experienced a myocardial infarction had concentrations of 

 S f 10-20 molecules above normal. It is known that more than 95% of the 

 myocardial infarctions occur in individuals who have hypertension. The 

 high incidence of exaggerated levels of the S f 10-20 fraction in 97% of the 

 cases examined offers an interesting correlation between hypertension and 

 this specific cholesterol fraction. Observations made on diabetic subjects 

 also indicated that the S f 10-20 fraction was markedly elevated above 

 normal in a number of cases. A graphic representation of the relationship 

 between the concentration of the S f 10-20 fraction in the serum of normal 

 men as contrasted with the values for this fraction in the serum of patients 

 who had previously suffered from myocardial infarction or who had 

 diabetes, is given in Figure 6 on p. 474. 



Figure 7 gives examples of flotation diagrams obtained by Gofman 

 et a/. 96 from samples of rabbit and human blood serum after ultracentrifuga- 

 tion. See p. 475. 



d'. The Relationship of Fractions Higher Than S f 10-20 to Athero- 

 sclerosis: In more recent studies of the Gofman group, 98 - 785-768 it has 

 been disclosed that the group of serum lipoproteins containing cholesterol 

 represents a large number of different varieties having densities from 1.12 

 g./ml. to less than 1.0 g./ml. Lindgren et al. 766 and Jones et a 7 . 767 have 

 been able to demonstrate several discrete entities as follows: S f 2, S f 4, 

 S f 6, S f 8, S f 10, S f 13, and S f 17. These differ from each other in physical 

 properties as well as in chemical structure. There are likewise additional 



765 J. W. Gofman, F. T. lindgren, H. B. Jones, T. P. Lyon, and B. Strisower, J. 

 Gerontol, 6, 105-119 (1951). 



766 F. T. Lindgren, H. A. Elliott, and J. W. Gofman, J. Phys. & Colloid Chenu, 55, 

 80-93(1951). 



767 H. B. Jones, J. W. Gofman, F. T. Lindgren, T. P. Lyon, D. M. Graham, B. Stris- 

 ower, and A. V. Nichols, Am. J. Med., 11, 358-380 (1951). 



768 J. W. Gofman, Bull. New York Acad. Med., 28, 279-293 (1952). 



