The study by Havell, Eder, and Bragdon investigates the distribution and chemical composition of ultracentrifugally separated lipoproteins in human serum. They describe a method that combines preparative ultracentrifugation with chemical analysis to accurately determine the distribution and composition of lipoproteins. The method involves raising the density of serum by adding concentrated salt solutions and then performing ultracentrifugation to separate lipoproteins into different fractions based on their density. The separated fractions are analyzed for total cholesterol, lipid phosphorus, and protein content. The results show that ultracentrifugation at a density of 1.063 separates lipoproteins into two components with distinct compositions. The low-density fraction (D < 1.063) contains about 70% of the total cholesterol and 50% of the phospholipid, while the high-density fraction (D > 1.063) contains the remaining cholesterol and phospholipid. The study also examines the distribution and composition of lipoproteins in young adults, patients with hyperlipoproteinemia, and various mammals. In patients with hyperlipoproteinemia, the concentration of the low-density fraction is increased, and the chemical composition of the fractions often shows alterations. In patients with liver disease, the lipid content of the high-density fraction is decreased, and the low-density fractions are uniformly increased. The method is compared with other techniques, such as analytical ultracentrifugation and Cohn fractionation, and it is found to be reliable and accurate. The study also discusses the subfractionation of the high-density fraction and the presence of a lipid phosphorus fraction that is not cholesterol. The results provide valuable insights into the distribution and composition of serum lipoproteins and their changes in various disease states.The study by Havell, Eder, and Bragdon investigates the distribution and chemical composition of ultracentrifugally separated lipoproteins in human serum. They describe a method that combines preparative ultracentrifugation with chemical analysis to accurately determine the distribution and composition of lipoproteins. The method involves raising the density of serum by adding concentrated salt solutions and then performing ultracentrifugation to separate lipoproteins into different fractions based on their density. The separated fractions are analyzed for total cholesterol, lipid phosphorus, and protein content. The results show that ultracentrifugation at a density of 1.063 separates lipoproteins into two components with distinct compositions. The low-density fraction (D < 1.063) contains about 70% of the total cholesterol and 50% of the phospholipid, while the high-density fraction (D > 1.063) contains the remaining cholesterol and phospholipid. The study also examines the distribution and composition of lipoproteins in young adults, patients with hyperlipoproteinemia, and various mammals. In patients with hyperlipoproteinemia, the concentration of the low-density fraction is increased, and the chemical composition of the fractions often shows alterations. In patients with liver disease, the lipid content of the high-density fraction is decreased, and the low-density fractions are uniformly increased. The method is compared with other techniques, such as analytical ultracentrifugation and Cohn fractionation, and it is found to be reliable and accurate. The study also discusses the subfractionation of the high-density fraction and the presence of a lipid phosphorus fraction that is not cholesterol. The results provide valuable insights into the distribution and composition of serum lipoproteins and their changes in various disease states.