Bengt Swahn

Studies on Lipids, Proteins and Lipoproteins in Serum from Newborn Infants

With new micromethods it has been possible to determine in 0.6 ml serum the concentration of total and free cholesterol, phospholipids, and total lipids, and to perform electrophoretic separation of the protein fractions as well as of the various lipid fractions. Sera from blood of the umbilical cord and from capillary blood from 50 infants 1–6 days old were analysed. The cholesterol, the total lipids and the phospholipids increased 70–80 per cent during the first few days of life. The marked increase in the lipids in the serum after birth was ascribable above all to the striking increase in the β‐fraction, but also to the lipids in the fraction termed “chylomicrons”. The α1‐fraction showed a moderate but statistically significant increase. During the first few days of life the α‐ and β‐globulins showed a statistically significant increase while the γ‐globulin showed a statistically significant decrease. The albumin fraction did not change significantly.

Demonstration of large blood protieus in cerebrospinal fluid

THE ORIGIN of the proteins in the cerebrospinal fluid is still conjectural. The electrophoretic mobility of these proteins when studied with paper electrophoresis does not differ from that of serum proteins. In addition, the cerebrospinal fluid proteins are usually precipitated by antihuman serum, which also suggests that they are identical with the serum proteins. On the other hand, in some respects, the proteins in cerebrospinal fluid differ from those in blood. The normal fluid protein pattern will thus show 1 or 2 prealbumin fractions and a &-fraction, which are not found in the serum by usual paper electrophoresis. The p,-globulin fraction is rather large and the 7-globulin fraction relatively low in the cerebrospinal fluid in comparison with serum. Furthermore, by immunoelectrophoresis, the transfenin is found to have a different appearance in the cerebrospinal fluid.l.2 The protein pattern of pathologic cerebrospinal fluid sometimes resembles that of serum very much, and increased diffusion of blood proteins into the cerebrospinal spaces then may be assumed. This resemblance of the electrophoretic curve for fluid proteins with serum proteins may not entirely be due to diffusion of proteins into the central nervous system. Thus, Frick and Scheid-Seydel,a who used labeled proteins, showed that proteins may be synthetized within the central nervous system. Therefore, the possibility of demonstrating or excluding the presence of large molecules of normal blood proteins-which because of their size and molecular complexity per se can be excluded as being of central nervous originin the cerebrospinal fluid may be valuable. Microimrnunoelectrophoresis, which requires only very small amounts of protein sample, permits serial analysis of a given specimen with special antisera and staining methods. This paper is concerned with the Occurrence and diagnostic value of diffusion of large normal blood proteins into the cerebrospinal fluid. The fluid was studied for the presence of the following 4 blood proteins: 1. al-Epoprotein is an ellipsoid-spherical molecule with a molecular weight of 200,000. Its appearance in the cerebrospinal fluid has been discussed in a previous paper.* 2. a2-macroglobulin was isolated by Schultze and associatess in 1955. It appears that the cerebrospinal fluid has hitherto not been studied for this protein. It is a spherical glycoprotein with a molecular weight of 846,000. On paper electrophoresis, this protein migrates as an a2-globulin. 3. /+lipoprotein is a spherical molecule with a molecular weight of 1,300,000. The occurrence in the cerebrospinal fluid of this component has been discussed in the above-mentioned paper. 4 4. Fibrinogen has a cross-sectional diameter of 38 A and a length of 700 A. It is thus a very long ellipsoid molecule. Its molecular weight is 330,000. Fibrinogen has been demonstrated also in cerebrospinal fluid samples without any clotting web. 6

Identification of separate proteins in cerebrospinal fluid with the aid of micro-immuno-electrophoresis.

This study is mainly concerned with the identification of the separate proteins in the cerebrospinal fluid (CSF) . Micro-immuno-electrophoresis according to Heremans’ modification of the Scheidegger method has been used. The various antisera employed were supplied by Behringwerke. Detailed descriptions of the methods, the samples, and the results in respect of various neurological diseases have been published elsewhere (Bronnestam, Dencker & Swahn 1960).