Biochemical and ultrastructural studies on subacute sclerosing panencephalitis and demyelination

Protection of neocortical tissue prisms from freeze-thaw injury by dimethyl sulphoxide

Neocortical tissue prisms prepared from rat and human brain were frozen to -196 degrees C by a two-step freezing procedure and 10% dimethyl sulphoxide as cryoprotectant. Frozen and thawed rat neocortical prisms incorporated glucose into acetylcholine and carbon dioxide at 89% and 86% of control values, respectively, and noradrenaline uptake into frozen and thawed rat prisms was 94% of the control value. Frozen and thawed prisms from three human neocortical specimens showed a similar degree of protection from freeze-thaw injury.

Biochemical study on myelin in adrenoleukodystrophy

Two myelin fractions, heavy and light, were isolated from white matter of a patient with adrenoleukodystrophy. Morphologically, heavy myelin fraction showed compact lamellar structures, and light myelin fraction consisted of loose lamellar structures and rod-like clear space. Analytical studies demonstrated that the chemical composition of heavy myelin fraction was almost the same as that of normal myelin and that light myelin fraction consisted mainly of cholesterol. Long chain saturated fatty acids, C25:0 and C26:0, were increased and C24:1 was decreased in sphingoglycolipids of heavy myelin fraction of the patient.

Fatty acid composition of myelin isolated from the brain of a patient with cellular deficiency of co-enzyme forms of vitamin B12

Myelin fractionation and subsequent lipid isolation have been carried out on a brain from a patient who suffered from a cellular deficiency of the adenosylcobalamin and methylcobalamin co-enzyme forms of vitamin B12. Examination of the fatty acid composition of choline and ethanolamine glycerophospholipids indicated a relative enrichment of odd-chain fatty acids which were identified by gas-liquid chromatography-mass spectroscopy as C15, C15:1, C17 and C17:1. A mixture of methyl branched C17 fatty acids was also identified. Odd-chain fatty acids accounted for 9.8% of the total fatty acid in the myelin choline phospholipid conpared to control values of 1.2%. The affected brain myelin phospholipids had a lower unsaturated fatty acid content. Examination of the myelin sphingolipids, sphingomyelin, cerebroside and sulfatide, yielded abnormal fatty acid profiles. The sphingomyelin contained only small amounts of C24:1 fatty acid. Both normal and hydroxy fatty acid containing cerebroside and sulfatide had reduced levels of C24 fatty acid. Determination of the relative hydroxy and normal fatty acid content of the galactolipids indicated an abnormally high hydroxy fatty acid level. Abnormal fatty acid profiles of brain cerebral sphingolipids have not been previously described in cases of vitamin B12 deficiency. Whether or not these alterations are characteristic will only be established by estimating sphingolipids in other such cases.

Neurochemical findings in a perinatal sudanophilic leukodystrophy rich in steryl ester

Neurochemical and neuropathological studies have been made of a 10-day-old child who suffered from a sudanophilic leukodystrophy. The brain white matter contained abundant sudanophilic material. The patient's grey matter total cholesterol content was 30% higher than whole brain tissue derived from a comparable control. White matter cholesterol content was more than double the control value. Nearly 80% of the white matter cholesterol was esterified. Subcellular fractionation of the white matter resulted in a "floating fraction" rich in cholesteryl ester. The steryl ester fatty acid composition was not typical of control tissue or demyelinating tissue. Patient phospholipid fatty acid composition patterns differed from control, but white matter galactolipid fatty acid composition appeared normal. Cholesteryl ester hydrolase activity appeared normal. Myelin and myelin-like fractions, isolated from diseased and normal brain tissue, were of a primitive developing nature but appeared to be comparable. The findings indicate a neonatal sudanophilic leukodystrophy which doubtless began in prenatal life and which was rich in cholesteryl ester. The aetiology of the leukodystrophy is unknown.

Neurochemical findings in adreno-leukodystrophy

The results of neurochemical examination of brain tissue derived from 2 cases of adreno-leukodystrophy have been presented. Both white and grey matter contained suadanophilic material. Although free fatty acid was also present, cholesteryl ester accounted for the bulk of the sudanophilic material. Total cholesterol, galactolipid and phospholipid content was reduced in both white and grey matter. The lipid loss was particularly severe from white matter indicative of considerable demyelination. Cholesterol was found to be the only major sterol present in white or grey matter. Subcellular fractionation of the diseased white matter resulted in myelin and two related fractions, one of which was very fatty and was rich in steryl ester. Morphological examination of myelin indicated loosely-packed lamellae. All of 3 fractions had adenosine 2',6'-cyclic nucleotide-3'-phosphohydrolase activity. Myein and the fraction not rich in cholesteryl ester had discernable basic protein bands when examined by polyacrylamide gel electrophoresis. Analysis of the fatty acid composition of choline and ethanolamine glycerophospholipids indicated a general increase of saturated fatty acids, relative to control values and a decrease in long-chain fatty acids. Examination of sphingomyelin fatty acids also demonstrated a loss of long-chain fatty acids. The fatty acid composition of the cholesteryl esters from white and grey matter differed. The findings indicate generalized damage to the brain, both of white and grey matter, with the damage to the white matter being much more severe. No abnormal sterol or other lipid was isolated.

Lipid and basic protein interaction of myelin

1. Purified myelin labelled with [(3)H]myo-inositol or [1-(14)C]acetate was incubated with trypsin or acetylated trypsin at 37 degrees C, pH8.0 for 30min. 2. After incubation and centrifugation analysis of the myelin pellet showed marked digestion of basic protein on polyacrylamide-gel electrophoresis. Proteolipid and Wolfgram proteins remained unchanged. 3. A loss of 15% of total protein and loss of all classes of lipids was also found. Most significant lipid losses were phosphoinositides, phosphatidylserine and sulphatide. 4. A low-density material containing more phospholipid than cholesterol and galactolipid was isolated from the supernatant obtained after centrifugation of trypsin-treated myelin. 5. Interaction of sulphatide and myelin basic protein was shown to take place in a biphasic system. Basic protein does not form any complex either with cerebroside or cholesterol in the same solvent system. 6. The release of acidic lipids from myelin suggests that they may be linked to basic protein by ionic forces and the neutral lipids may be by lipid-lipid interactions. 7. The relevance of these studies as a model of brain degeneration is discussed.