Separation and characterization of cord serum lipoproteins.

Blood was collected from the umbilical cord of infants with a 1-min Apgar score of 9 to 10. Total cord serum lipoproteins were isolated by ultracentrifugation, at a density of 1.220 g/ml. The isolated serum lopoproteins were then separated by gel filtration chromatography on 6% agarose. The overall recovery of the separated lipoprotein cholesterol was 90% or greater. In cord serum, four lipoprotein peaks were found, whereas three peaks were present in adult lipoproteins. The major lipoproteins of cord serum correspond to low density lipoprotein (LDL) and high density lipoprotein (HDL). Very low density lipoproteins (VLDL) were heterogeneous in cord serum. After gel filtration chromatography, the distribution of cord serum cholesterol is about 5% in peak 1, 10% in peak 2, 40% in peak 3 (LDL), and 45% in peak 4 (HDL). An additional difference between the lipoproteins isolated from cord serum and those from adult serum was the slower electrophoretic mobility of cord serum VLDL in agarose gel.