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Biomedical subjects

I Goto

Publications and source records attributed to I Goto.

At least 235 records · Page 13Linked to original sources
PubMed1985

Hydrolysis of galactosylceramide is catalyzed by two genetically distinct acid beta-galactosidases.

Two genetically distinct acid beta-galactosidases are apparently involved in the hydrolysis of galactosylceramide in fibroblasts. These beta-galactosidases were activated by different bile salts. The classical galactosylceramidase (galactosylceramidase I, EC 3.2.1.46) was activated by sodium taurocholate, while the other galactosylceramidase (galactosylceramidase II) was activated by sodium cholate. The former was genetically lacking in globoid cell leukodystrophy (GLD) and the latter in GM1 gangliosidosis. Galactosylceramidase II cross-reacted with antibody raised against purified GM1 ganglioside beta-galactosidase (EC 3.2.1.23) from the human placenta. The purified beta-galactosidase had galactosylceramidase II activity, which was competitively inhibited by GM1 ganglioside. Thus, galactosylceramidase II seems to be identical to GM1 ganglioside beta-galactosidase and lactosylceramidase II. Galactosylceramidase II had a very low affinity for galactosylsphingosine. In the galactosylceramide-loading tests using fibroblasts from patients with GLD and GM1 gangliosidosis, both cell lines hydrolyzed the incorporated galactosylceramide, with lower rates than control fibroblasts but higher than the fibroblasts from patients with I-cell disease, in which both galactosylceramidase I and II were deficient. These results indicate that galactosylceramide is hydrolyzed by two genetically distinct beta-galactosidases and explain well that galactosylsphingosine but not galactosylceramide accumulates in the brain of patients with GLD.

Cell Line↗
PubMed1985

Galactosylceramide- and lactosylceramide-loading studies in cultured fibroblasts from normal individuals and patients with globoid cell leukodystrophy (Krabbe's disease) and GM1-gangliosidosis.

The metabolism of galactosylceramide and lactosylceramide in cultured fibroblasts was studied using the lipid-loading test. These compounds were incorporated into the fibroblasts yet only small amounts of the incorporated lipids were hydrolyzed unless additional phospholipid was mixed with the glycolipid before loading. Among phospholipids, phosphatidylserine was the most effective for incorporation and hydrolysis of the glycolipids, while phosphatidylcholine inhibited the incorporation of the glycolipids. Using filtration techniques, light scattering analyses and subcellular fractionation, the particle size of glycolipid in the culture medium was found to be critically important for the incorporation of the lipids into the cells and their transportation to the lysosomes. The particle sizes of the glycolipids were decreased by mixing with phosphatidylserine. Furthermore, the negative charge in phosphatidylserine may be necessary for the glycolipid transportation into the lysosomes. In fibroblasts from patients with globoid cell leukodystrophy, 40-50% of galactosylceramide was hydrolyzed on the 4th day of culture, a time when the control fibroblasts had hydrolyzed it about 80%. This finding is in contrast with observations made on fibroblasts with other sphingolipidoses which showed near-zero degradation in corresponding substrate-loading tests. In fibroblasts from patients with either globoid cell leukodystrophy of GM1-gangliosidosis, hydrolysis of lactosylceramide was fairly normal yet somewhat lower than control values on any day of culture, thereby indicating that, in the loading tests, lactosylceramide seems to be hydrolyzed with similar levels of enzyme activities by two distinct beta-galactosidases, galactosylceramidase and GM1-ganglioside beta-galactosidase.

Cell Line↗
PubMed1985

Tightly bound fatty acids in the erythrocyte membrane proteins in myotonic dystrophy.

The composition of "tightly bound fatty acids" and of loosely bound fatty acids in the erythrocyte membrane proteins from patients with myotonic dystrophy were compared with those of sex- and nearly age-matched normal controls. No significant differences could be detected in the composition of tightly bound fatty acids and there was no gross abnormality in the composition of loosely bound fatty acids between myotonic dystrophy patients and normal controls, although small differences were observed.

Adolescent↗
PubMed1985

Very long-chain fatty acids in neutral lipids and glycerophospholipids of adrenoleukodystrophy-cultured skin fibroblasts.

Three major lipid fractions, i.e., cholesterol ester, triacylglycerol and glycerophospholipids, were investigated cultured fibroblasts to clarify whether very long-chain fatty acids were accumulated or not. Abnormally accumulated very long-chain fatty acids were confirmed in all three lipid fractions. Our results support our previous report that there may be a generalized abnormal metabolism of very long-chain fatty acids in adrenoleukodystrophy.

Adrenoleukodystrophy↗
PubMed1985

Fatty acid compositions of erythrocytes, mononuclear cells and blood plasma of patients with myotonic dystrophy.

Fatty acid compositions of erythrocyte membrane phospholipids including phosphatidylethanolamine subclasses, blood plasma and mononuclear cells of 8 patients with myotonic dystrophy (MyD) and 8 normal controls were analyzed by high performance liquid chromatography. Slight changes (decreased C18:2 and increased C16:0) in the fatty acid compositions of erythrocyte membrane glycerophospholipids and blood plasma lipids were observed in MyD. There was no significant difference in the fatty acid composition of mononuclear cells between MyD and normal controls. It seems that no essential defect exists in either the erythrocyte membrane fatty acid composition or the fatty acid metabolism itself in MyD.

Adolescent↗
PubMed1985

Fabry's disease with partially deficient hydrolysis of ceramide trihexoside.

A report is presented on biochemical studies of the fibroblasts from a 26-year-old man with Fabry's disease whose clinical picture was atypical. The patient had severe pain in the extremities, but no angiokeratomas, corneal clouding or hypohidrosis. The trihexosylceramidase activity in the fibroblasts in vitro was deficient. The level and Km value of the residual activity were similar to levels seen in typical Fabry's patients. However, fibroblasts from the patient cultured in medium supplemented with [3H]ceramide trihexoside hydrolyzed the labeled ceramide trihexoside much higher than did cells from typical Fabry's patients, implying that the patient has a partial defect in hydrolysis of trihexosylceramide in cultured fibroblasts.

Adult↗
PubMed1985

A study on erythrocyte membrane plasmalogen in myotonic dystrophy.

Phospholipid classes that included plasmalogens of erythrocyte membranes in seven myotonic dystrophy (MyD) patients and seven normal controls were analyzed by HPLC. No significant difference in phospholipid classes was found between patients with MyD and normal controls, but there was a visible difference in peak profiles of compounds of the phosphatidylethanolamine class. In the study of plasmalogens, we used two preparation methods: exposure to HCl and deacylation with mild alkaline. The area ratio of the plasmalogen form to the diacyl form in the phosphatidylethanolamine class of MyD erythrocyte membranes was significantly lower than that of normal controls. Fatty acid analyses showed that fatty acids of both phosphatidylethanolamine subclasses have less unsaturation in MyD.

Adolescent↗
PubMed1985

Adrenoleukodystrophy: fatty acid analysis of total glycerophospholipids in erythrocyte membranes.

The saturated fatty acids released from the erythrocyte membranes of four patients with adrenoleukodystrophy (ALD) and 14 diseased controls were analyzed by high performance liquid chromatography. The ratios of C26:0 to other saturated fatty acids in ALD were higher than those of diseased controls, and neither false-positive nor false-negative samples were observed. These results suggest that a study of fatty acids of total glycerophospholipids in erythrocyte membranes by high performance liquid chromatography is a useful diagnostic method of ALD.

Adrenoleukodystrophy↗
PubMed1985

Adrenoleukodystrophy: abnormality of "tightly bound" fatty acids in the erythrocyte membrane proteins.

"Tightly bound" and "loosely bound" fatty acids in erythrocyte membranes were analyzed in three patients with adrenoleukodystrophy, three probable carriers, and eight controls. The ratios of C28:0 or C26:0 to C22:0 or C20:0 in the tightly bound fatty acids of three patients were significantly higher than those of controls, and the ratios in two of three probable carriers were higher than those in controls. The ratios of C26:0 to C22:0 or C20:0 in the loosely bound fatty acids of three patients and three probable carriers were also significantly higher than those of controls. Since tightly bound fatty acids in membrane proteins are found not only in erythrocyte membranes but also in myelin proteins, the abnormality of tightly bound fatty acids may be related to the demyelination in adrenoleukodystrophy.

Adolescent↗
PubMed1985

Plasmalogen analysis in erythrocyte membranes of adrenoleukodystrophy.

Very long-chain fatty acids accumulate in both adrenoleukodystrophy and Zellweger's syndrome. Plasmalogen content is decreased in Zellweger's syndrome. We therefore analyzed plasmalogen in erythrocyte membrane glycerophospholipids of three patients with adrenoleukodystrophy and eight normal controls. There was no significant difference in the ratio of plasmalogen and diacyl forms in the phosphatidylethanolamine class of the patients and controls. This observation suggests that plasmalogen metabolism differs in adrenoleukodystrophy and Zellweger's syndrome.

Adrenoleukodystrophy↗