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Copyright of Journal of Neurology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Zeitschrift Für Neurologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An improved preparation of proteolipid from bovine brain white matter is described. The product obtained by repeated acetone precipitation is completely soluble in chloroform-methanol and has a fairly constant composition: 35% protein, 40% galactocerebroside, and about 25% phospholipid.

The molar ratios of N-acetyl neuraminic acid, hexose, hexosamine, and sphingosine have been determined for the abnormal ganglioside in Tay-Sachs disease that was previously detected as a fast-moving band in thin-layer chromatography, and in two abnormal fast-moving bands of gangliosides from the cortex and white matter of the brain in cases of gargoylism and Niemann-Pick's disease. The fastest-moving ganglioside band in these two conditions contains neither hexosamine nor glucose.

The fatty acid composition of cerebrosides and sulfatides from frontal lobe gray and white matter was determined for five fresh and four formalinized adult brains and for eight infants. Fatty acid patterns were unaffected by formalinization, but varied considerably from one another in the proportion of saturated to unsaturated fatty acids.The percentages of 24:0 and 24:1 increased with age. Cerebrosides obtained from areas such as the brainstem and cerebellum, where myelination was more advanced, tended to have a larger proportion of long-chain fatty acids than samples extracted from frontal or parietal lobe white matter. Hydroxy fatty acids showed an adult pattern in all instances in which amounts sufficient for accurate quantification could be isolated.Lipid hexose, cerebroside + sulfatide hexose, and methanoleluted hexose were measured in the brains of 12 infants ranging in age from a 4 month fetus to 2 yr. In the most immature, the majority of lipid hexose was in the form of glycolipids more polar than cerebrosides and sulfatides. These have tentatively been identified as hematosides and globosides. With maturation, cerebrosides and sulfatides increased progressively, but the amounts of the more polar glycolipids remained constant in relation to the total lipid content of tissue.

Fatty acids from cerebrosides and cerebroside sulfates and those bound by ester linkage from white and gray matter of frozen phenylketonuric brains were determined and compared with analyses of nonphenylketonuric brains. A decrease in the major monoenoic acid relative to the major saturated acid (18:1/18:0, or 24:1/24:0, or 24h:1/24h:0) of each fraction analyzed is observed in this disease. The amounts of cholesterol, cerebroside, and cerebroside sulfate in the brain are not altered in phenylketonuria.The sum of the three polyunsaturated fatty acids 20:4, 22:5, and 22:6 constitute approximately 30% of the ester-bound fatty acids of human cortical gray matter.

Gray matter, white matter, and myelin were isolated from the frontal lobes of humans aged 10 months, 6 yr, 9 yr, and 55 yr and the lipid compositions of each were determined. Myelin had a much higher lipid content (78–81% of the dry weight) than white matter (49–66%) or gray matter (36–40%). Myelin contained much higher molar percentages of cerebroside and cerebroside sulfate, slightly higher molar percentages of cholesterol, and lower molar percentages of ethanolamine glycerophosphatides and choline glycerophosphatides than gray matter. The molar percentages of serine glycerophosphatides and sphingomyelin were about the same in each tissue.The aldehyde content of glycerophosphatides, expressed as molar percentage of the total lipoidal residues in each lipid, were as follows: ethanolamine glycerophosphatides from myelin 40–50%; ethanolamine glycerophosphatides from gray matter 21–27%; serine glycerophosphatides from myelin 21–36%; serine glycerophosphatides from gray matter 0.3–3.8%. Choline glycerophosphatides from either tissue contained only traces of aldehydes.The extra-myelin portion of white matter had a lipid composition that was very similar to that of myelin, but quite different from that of gray matter.Assuming a molecular weight of 28,000 for myelin protein(s), it was calculated that for each protein molecule in human myelin there are 186 lipid molecules, 111 of which are polar lipids and 75 of which consist of cholesterol. The over-all molar ratios of the polar lipids are phosphatidal ethanolamine:serine glycerophosphatides:choline glycerophosphatides:sphingomyelin:cerebroside:cerebroside sulfate:ceramide:uncharacterized lipids 25:9:20:9:29:7:3:9. It was calculated that the molar ratio of protein amino acids to polar lipids in human myelin is 2.38 to 1.