Brain lipids of a still-born 28-week-old fetus from a pregnant woman with severe hydramnion.

Some of the total brain weighing 370 g of a 28-week-old fetus who had been still-born from a pregnant woman with severe hydramnion as used for the experiment. The fetal brain was dissected into the cortex and medulla of cerebral frontal, parietal and occipital lobes, and the cerebellum. Various lipids of them were analysed in detail. The total lipids constituted 2.1-2.8% of the tissue wet weight, respectively, in every portion of the fetal brain. The total cholesterol and total phospholipids constituted 19-25% and 72-80% of the total lipids, respectively, in it. Particularly, the fetal brain showed some characteristic features of lipids which are not observed in neonatal, infantile and adult brains; a trace amount of galactolipids, a presence of cholesterol ester constituting 0.4-0.9% of the total lipids and a large amount of phosphatidylcholine constituting 57-73% of the total phospholipids. This suggests that myelination was still not active in the brain of 28-week-old fetus. However, the medulla showed a higher ratio of ethanolamine-plasmalogen to phosphatidylethanolamine than the cortex. This indicates that the brain of 28-week-old fetus is at the primary stage of the differentiation into the gray and white matters. The total ganglioside contents were 0.9-1.0 mumol N-acetylneuraminic acid/g wet weight of the cerebral tissues and 0.3 mumol N-acetylneuraminic acid/g wet weight of the cerebellum. The molar percent distribution of gangliosides showed no difference between the medulla and cortex in the cerebrum, but a difference between the cerebral and cerebellar tissues.