ABDERHALDEN (1908) first reported that the lipid concentration of red cells differed from that of plasma. He reported that human red cells contain no neutral fat and that the fatty acids are combined with phospholipids and to some extent with cholesterol. Subsequent analyses of the lipids of human red cells do not permit comparison because of the variety of methods utilized. Erickson, Avrin, Teague and Williams (1940) and Hack (1947) characterized the phospholipids as cephalin, lecithin and sphiiigomyelin. Brun (1939) found that cholesterol existed in the free form with no appreciable amount of ester. Klenk and Lauenstein (1933) reported that the stroma contained 25 per cent of fatty acids.Only a few isolated attempts have been made to identi9 the fatty acids associated with the phospholipid fraction in human rcd cells. Chevallier, Manuel and Rouillard (1951) were first to report the presence of dienes, trienes in trace amounts, tetraenes and oleic acid. By employing reference standards of pure acids, Evans, Waldron, Oleksyshyn and Riemenschneider (1956) confirmed the findings of Chevallier and co-workers (1951) and reported the presence of pentaenes and hexaenes. They estimated the concentration of oleic acid from the iodine number, and the saturated fatty acids were then expressed as the difference between the total fatty acids and the unsaturated fatty acids.The present study was undertaken to measure the lipid constituents of the normal human red cell and to determine whether their constituents arc altered in diseases of the red cell. Data were obtained for three basic lipid componentsunsaturated fatty acids, saturated fatty acids and cholesterol. Because the lipids in red cells are primarily structural in function and are concentrated at the surface of the cell (Ponder, 1954), the amount of lipid was related to the surface area.
MATERIALS AND METHODSTwo hundred ml. of blood were withdrawn from the aiitecubital vein of fasting subjects into a siliconized bottle containing 20 mg. of heparin. A sample was removed immediately for red-cell photonlicrographs (Houchin, Munn and Parnell, 1958). The platelets were separated from the red cells by centrifuging at 500 r.p.m. for 45 minutes. The buffy coat was separated by centrifuging the cells at 2400 r.p.m. for 3 0 minutes. The packed red cells were washed three times with an equal volume of fresh saline. In every wash the cells were separated from saline by centrifuging at 2400 r.p.m. for 3 0 minutes. A sample was removed for determination of packed-cell volumc by the microhaeniatocrit method (Houchin, Lainanna and Lanibert, 1955) and haemoglobin (Crosby, M u m and Furth, 1954). The rciiiaining portion was treated with carbon monoxide to get rid of oxyhaeinoglobin and was then mixed with ignited sea sand. Purified ethanol-diethylether (3 :I) was added slowly with a swirling motion.The lipids were extracted by boiling under reflux for exactly I minute with twenty
1. A photomicrographic method was devised for the measurement of the dimensions of red cells in rouleaux in plasma. With normal blood valid conclusions were drawn from 80 cell measurements with a high degree of confidence.
2. The mean corpuscular volume and the surface area were computed from these dimensions by formulae which treated the cell as a spheroid.
3. The dimensions, mean corpuscular volume and surface area of normal human red cells were as follows: 8.28 µ diameter, 1.71 µ thickness, 82 µ3 volume and 134 µ2 surface area.
4. The computed mean corpuscular volume was in agreement with the refractometric determination.
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