Retinal pigment epithelial degeneration associated with leukocytic arylsulfatase A deficiency

A family exhibiting a leukocytic arylsulfatase A deficiency, probably inherited in an autosomal recessive manner, differed from patients with typical metachromatic leukodystrophy in that sulfatiduria was absent and there was readily detectable cerebroside sulfatase activity. To our knowledge, this family was unique in that there were no known members with metachromatic leukodystrophy and the only neurologic abnormality was progressive retinal pigment degeneration in the proband.

Incorporation of glucosamine by activated human neutrophils. A myeloperoxidase-mediated process

Zymosan-activated neutrophils were found to incorporate large amounts of [3H]glucosamine into TCA-precipitable material as compared with resting cells. The burst of glucosamine incorporation began 2 min after zymosan exposure and lasted 3 to 5 min, after which the incorporation rate returned to that of resting cells. Studies with cells from patients with chronic granulomatous disease and hereditary myeloperoxidase deficiency as well as experiments with inhibitors indicated that glucosamine incorporation required both the respiratory burst and the myeloperoxidase system. SDS-polyacrylamide gel electrophoresis of [3H]glucosamine-containing TCA precipitates from zymosan-activated cells revealed radioactivity migrating throughout the length of the gel. The radioactivity in precipitates from resting cells or cells activated in the presence of a small amount of a myeloperoxidase inhibitor was found in a peak migrating close to the tracking dye. These results indicate that zymosan-activated neutrophils are able to incorporate glucosamine into protein by a process dependent on H2O2 and myeloperoxidase. The biosynthetic significance of this phenomenon is not certain, but it most likely represents the reaction of amino sugar with macromolecular degradation products formed by the action of the myeloperoxidase system on cellular and particulate constituents.

Application of "high-performance" liquid chromatography to the study of sphingolipidoses

Quantitative high-performance liquid chromatographic analysis of perbenzoylated sphingolipids has been used to study the correlations of body chemistry to clinical phenomena. Plasma sphingolipids were isolated from 32 Gaucher (β-glucosidase deficiency) and six Fabry (α-galactosidase deficiency) patients by solvent partition and chromatographic separation on silicic acid columns. Plasma sphingolipids from a patient undergoing plasma-exchange were separated from interfering lipids with reversed-phase columns. Liquid-chromatographic analysis of sphingolipids provides useful supportive information for diagnoses because affected individuals are shown to possess increased circulating concentrations of the pathognomonic sphingolipid. We also used this technique to monitor sphingolipid concentrations in plasma and urine sediment during plasma exchange of a p atient with Fabry’s disease. Regular plasma exchanges produced and maintained decreased concentrations of sphingolipids in plasma, but near pre-exchange concentrations were observed within days after the therapy was terminated.

Application of "high-performance" liquid chromatography to the study of sphingolipidoses

Quantitative high-performance liquid chromatographic analysis of perbenzoylated sphingolipids has been used to study the correlations of body chemistry to clinical phenomena. Plasma sphingolipids were isolated from 32 Gaucher (beta-glucosidase deficiency) and six Fabry (alpha-galactosidase deficiency) patients by solvent partition and chromatographic separation on silicic acid columns. Plasma sphingolipids from a patient undergoing plasma-exchange were separated from interfering lipids with reversed-phase columns. Liquid-chromatographic analysis of sphingolipids provides useful supportive information for diagnoses because affected individuals are shown to possess increased circulating concentrations of the pathognomonic sphingolipid. We also used this technique to monitor sphingolipid concentrations in plasma and urine sediment during plasma exchange of a p atient with Fabry's disease. Regular plasma exchanges produced and maintained decreased concentrations of sphingolipids in plasma, but near pre-exchange concentrations were observed within days after the therapy was terminated.

Carbonic anhydrase and 2',3' cyclic nucleotide 3'-phosphohydrolase activity in normal human brain and in demyelinating diseases

The activities of carbonic anhydrase and 2',3' cyclic nucleotide 3'-phosphohydrolase (CNPase) were measured in gray and white matter and in myelin from human brains obtained at autopsy. Carbonic anhydrase activity increased with age, and at all ages a major part of the activity was associated with membrane fractions. The percentage of membrane-bound carbonic anhydrase was lower than normal in white matter from Krabbe disease and adrenoleukodystrophy; isolated myelin had a low specific activity in these diseases. CNPase activity was decreased in both white matter and myelin, but was somewhat higher than normal in gray matter. Although the yield of myelin from a case of metachromatic leukodystrophy was markedly reduced, changes in the enzymes activities were minimal.

Carbohydrate metabolism in phenylketonuria

Carbohydrate metabolism was studied in 6 adult patients with phenylketonuria both on a low phenylalanine and an unrestricted institutional diet. Tolerance tests included PO glucose, PO phenylalanine, and combined glucose phenylalanine loading. Glucose, insulin, pyruvate, lactate, and phenylalanine were sampled at 0, 1/2, 1, 2, 3, and 4 hr. Fasting glucose levels were normal as were mean glucose values after challenge. Basal insulin secretion, as well as insulin response, to glucose challenge and to combined phenylalanine and glucose loading appeared normal. Insulin response to phenylalanine alone, however, was lower than expected in the phenylketonuria patients. Both off and on low phenylalanine diet, blood pyruvate and lactate were also normal. Thus, our data from blood did not show evidence of the abnormalities in glucose and pyruvate metabolism which have been proposed to occur in phenylketonuric patients but did not suggest that the potency of phenylalanine as an insulin secretagogue is diminished by chronic hyperphenylalaninemia.

A light and electron microscopic study of mannosidosis

The present work investigated the light and electron microscopic changes in hypertrophied gingiva in a patient with mannosidosis. The biopsy specimens studied covered a period of 20 months; biopsy specimens were taken before and after a therapeutic trial with oral and local zinc sulfate. The intensity of the disease was progressive, in spite of the zinc, and was characterized by marked hyperplasia of the epithelium and severe inflammation of the stroma. Many of the cells in the inflammatory infiltrate, as well as cells indigenous to the gingiva, showed a striking vacuolation of their cytoplasm. Histiocytes were most numerous and also were most heavily vacuolated, but fibroblasts, endothelial cells, plasma cells, and epithelial cells also manifested the vacuolar change. In the histiocytes, the vacuoles occupied most of the cytoplasm, ranged widely in size, and were contiguous, molded, and intercommunicating. The vacuoles were bound by a single membrane and were filled predominantly by a finely granular material of medium density but also by varying amounts of coarser, darker granules, fragmented membranes, myelin-like figures, lipid droplets, and small vesicles. The vacuoles were interpreted as being consistent with secondary lysosomes that contained excessively stored substrate, similar to what has been observed in the mucopolysaccharidoses, in which the vacuoles have also been demonstrated histochemically and cytochemically to contain acid phosphatase, a known lysosomal marker.

Leukocyte beta-glucosidase in homozygotes and heterozygotes for Gaucher disease

Human leukocytes contain at least two isozymes of 4-methylumbelliferyl-beta-glucosidase acting optimally at pH 4.0 and 4.8; in Gaucher disease, only the former is deficient. Brief exposure of the leukocyte homogenate to pH 4.0 at room temperature results in irreversible inactivation of the pH 4.8 activity, while the activity at pH 4.0 remains unaffected. The more acidic isozyme is stimulated four- to fivefold by 0.2% sodium taurodeoxycholate (TDC) with a shift in the pH optimum to 5.0. The less acidic isozyme is completely suppressed in the presence of this detergent. Both leukocyte isozymes appear to be membrane-bound since gel filtration of Sephadex G-200 produces only one peak of activity located at the void volume, unlike in liver and kidney where a second peak also can be demonstrated. Heat inactivation analysis indicated that in controls, assayed in the absence of detergent, pH 4.0 activity is more thermostable than pH 4.8 activity. However, in Gaucher disease, the residual beta-glucosidase at pH 4.0 is just as thermolabile as the unaffected pH 4.8 activity. Heat inactivation of the enzyme in the presence of TDC resulted in rapid loss of activity, suggesting a direct effect of the bile salt on the configuration of the enzyme decreasing its thermal stability. In the absence of detergent, acid beta-glucosidase shows two K(m)'s, one at 3.2 mM and another at 0.9 mM. In the presence of detergent, only the higher K(m) at 3.3 mM is obtained. In patients with Gaucher disease and in obligate carriers, the K(m) remains essentially unaffected while the V(max) shows the expected deficiency.A reliable and reproducible selective assay technique has been developed for the diagnosis of Gaucher disease homozygotes and obligate heterozygotes and for the carrier screening of individuals at risk for this inherited disorder. The efficacy of this technique has been demonstrated by studying the activity in 42 controls, 26 patients, 32 obligate heterozygotes, and 23 healthy relatives of patients with Gaucher disease.

Improved thin-layer chromatographic method in the diagnosis of mannosidosis

An improved thin-layer chromatographic method is described for the facile separation of neutral oligosaccharides excreted in the urine of patients with mannosidosis. The urine sample is treated with mixed-bed ion-exchange resin to remove charged species. The eluate is then chromatographed on silica gel thin-layer plates with n-propanol water as the developer. Eleven unique orcinol-positive components can thus be resolved. The advantages of this method over previously described techniques are the ease and rapidity of assay, better resolution of components, and clarity of resolution. It should be applicable to other disease states in which distinctive neutral carbohydrate products are produced.

Improved thin-layer chromatographic method in the diagnosis of mannosidosis

An improved thin-layer chromatographic method is described for the facile separation of neutral oligosaccharides excreted in the urine of patients with mannosidosis. The urine sample is treated with mixed-bed ion-exchange resin to remove charged species. The eluate is then chromatographed on silica gel thin-layer plates with n-propanol water as the developer. Eleven unique orcinol-positive components can thus be resolved. The advantages of this method over previously described techniques are the ease and rapidity of assay, better resolution of components, and clarity of resolution. It should be applicable to other disease states in which distinctive neutral carbohydrate products are produced.

Occurrence of novel branched-chain fatty acids in Refsum's disease

Two novel branched-chain fatty acids, which appear to be unsaturated analogs of phytanic acid, have been observed in sera and urine of patients with Refsum's disease. They occur in both phospholipids and neutral lipids, and have been isolated and characterized.

Effects of diet and behavior therapy on social and motor behavior of retarded phenylketonuric adults: an experimental analysis

The effects of a low phenylalanine diet on six retarded phenylketonuric adults were assessed. An ABA individual-subject design was used in experiment I to assess the effects of a low phenylalanine diet on social and motor behavior. Following a baseline during which the subjects ingested a normal phenylalanine diet (phase A), a low phenylalanine diet (phase B) was administered in a double blind fashion. Finally, the baseline condition (phase A) was reinstated (normal diet). The low phenylalanine diet resulted in few significant behavioral changes for those subjects with which proper methodologic controls were employed. However, for two of six subjects motor behavior, including stereotypy and tremor, seem to have ameliorated. In experiment II, applied behavior analysis techniques, including differential reinforcement of other behavior and time out, were combined to radically reduce the frequency of stereotypy and self-abuse exhibited by one of the six subjects of experiment I.

GM1-ganglioside beta-galactosidase in leukocytes and cultured fibroblasts

GM1-ganglioside hydrolysis by leukocytes and fibroblasts, tissues easily obtainable from patients, was investigated using 3H-labeled GM1 and was found to be at least as active as that reported for any other tissue. Sodium taurocholate was required for the reaction, the crude bile salt at an optimum concentration of 0.4% producing twice as much activity as pure taurocholate at its optimum concentration of 0.8%. Leukocyte GM1-ganglioside beta-galactosidase and 4-MU-beta-gal cleaving activities were similar, 134.5 +/- 23.3 and 179.8 +/- 25.4 nmol/h/mg protein, respectively. In cultured skin fibroblasts and amniotic fluid cells these enzyme activities were 4 to 5 times higher. Homozygotes for GM1-gangliosidosis showed negligible activity while in heterozygotes the leukocyte GM1-cleaving activity was reduced to one-third of control values. In leukocytes from patients with four other sphingolipid storage diseases the activity was either normal (Krabbe's, Tay-Sachs, Metachromatic leukodystrophy) or increased (adult Gaucher's).

Human leukocyte acid hydrolases: characterization of eleven lysosomal enzymes and study of reaction conditions for their automated analysis

The optimal reaction conditions and kinetic properties of eleven leukocyte acid hydrolases determined with the use of fluorigenic derivatives of 4-methyl-umbelliferone are described. The enzymes studied were acid phosphatase, aryl sulfatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucuronidase and alpha-fucosidase. More than 90% of the activity of each enzyme was released into a 27,000 X g supernatant by a double sonication procedure employing 0.9% sodium chloride and 0.1% Triton X-100. The Km values obtained were similar to those previously reported for chromogenic subtrates. A single Km value could not be derived for beta-galactosidase because its double reciprocal plot was not linear. All enzymes could be measured with less than 10 mug of protein within 15 min. Activators and inhibitors studied included the chloride salts of Na+, K+, Zn2+, Ca2+, Mg2+, Hg2+, and Fe2+ as well as p-chloromercuriphenysulfonate, glutathione, BAL, EDTA, EGTA, Triton X-100 and sodium taurocholate. The reaction conditions described in this report can be used for the diagnosis of various lysosomal storage diseases and should facilitate the development of automated procedures for the analysis of these eleven enzyme activities with small quantities of blood.

The pituitary-thyroid axis in adults with phenylketonuria

Serum thyroxine and triiodothyronine levels in 15 adult phenylketonuric patients on an unrestricted diet were normal despite reduced circulating tyrosine levels. Serum thyrotropin levels were normal in the basal state or in response to thyrotropin-releasing hormone in selected patients tested. These results support and extend previous observations of normal thyroid function in phenylketonuria.

Cholesterol metabolism in cultured fibroblasts in adrenoleukodystrophy

The basic biochemical defect of X-linked adrenoleukodystrophy (sudanophilic leukodystrophy, Schilder's disease) is unknown. To investigate reported abnormalities in cholesterol metabolism in vitro, we examined cultured skin fibroblasts of four patients and four normal control subjects. The kinetics of retention and accumulation of [14C]cholesterol by these cells was studied. After 3 days of exposure to tracer amounts of [14C]cholesterol, an apparent steady state between the medium and cellular cholesterol was established. The specific radioactivity expressed per mg of protein was similar for both Schilder and control fibroblasts. tafter labeling the pre-existing cellular cholesterol pool, the rate of loss of label was followed up for a 6-day period. About 23% and 14%, respectively, of the cellular radioactivity in both Schilder's disease and control cells were released into the medium after the consecutive change with fresh nonlabeled medium. No significant differences in [14C]cholesterol rates of uptake or release were observed between control and Schilder's disease fibroblasts. About 44% of the labeled cholesterol was present in an esterfied form after incubation in the presence of unheated serum in both Schilder's and control cultures.

Arylsulfatases A and B in metachromatic leukodystrophy and Maroteaux-Lamy syndrome: studies with 4-methylumelliferyl sulfate

Metachromatic leukodystrophy and Maroteaux-Lamy syndrome can be diagnosed by assay of leukocyte or fibroblast arylsulfatase A and B activity with the fluorogenic substrate 4-methylumbelliferyl sulfate. The arylsulfatases are extracted into a 27000 x g supernatant by sonication in 0.9% sodium chloride and then separated with CM-32 on columns or in test tubes. In 0.05 M sodium acetate pH 6.0, arylsulfatase A is not absorbed while arylsulfatase B is retained by the resin. The arylsulfatase B is then eluted from the resin with 0.3 M sodium chloride. The arylsulfatase A activity obtained from normal leukocytes and fibroblasts is linear for the initial 10 minutes of the reaction, is stimulated 3-fold by 6 mM lead acetate and inhibited 80% by 0.24 mM silver nitrate. After separation with CM-32, the arylsulfatase B activity is stimulated 3-fold by Triton X-100 (0.1%). Arylsulfatase A but not arylsulfatase B is destroyed by heat (60 degrees). Both leukocyte and fibroblast arylsulfatase A activity was reduced to 11% of control values in metachromatic leukodystrophy. Essentially no arylsulfatase B activity was detected in cells from patients with Maroteaux-Lamy syndrome. Metachromatic leukodystrophy heterozygotes but not Maroteaux-Lamy syndrome heterozygotes can also be distinguished by this method. A heat inactivation technique utilizing the differential thermal stabilities of the two enzymes for diagnosis of patients with Marotezux-Lamy syndrome is also described. The advantages of these 4-methylumbelliferyl sulfate assay procedures over the p-nitrocatechol sulfate method of assay are greater sensitivity, selectivity for the desired enzyme and potential for use in large scale testing.

Enzymatic block in the synthesis of gangliosides in DNA virus-transformed tumorigenic mouse cell lines

The ganglioside pattern of both SV40- and polyoma virus-transformed mouse cell lines differs from that of the parent cell lines or of cell lines that have transformed spontaneously in tissue culture. This is manifested by a dramatic decrease of gangliosides with an oligosaccharide chain larger than sialyllactose. Present investigations indicate that this change probably cannot be attributed to excessive catabolism of gangliosides, but is caused by impaired synthesis of tri- and tetrahexosyl gangliosides in the virus-transformed cell lines. We present evidence for the block of a required step for the biosynthesis of these ganglioside homologs. The block involves the enzyme catalyzing the transfer of N-acetylgalactosamine from uridine diphosphate N-acetylgalactosamine to hematosides (N-glycolylneuraminyl or N-acetylneuraminylgalactosylglucosyl ceramide). This well-defined enzymatic change opens the way for studies of the biochemical mechanism of the alteration of cell membranes which occurs after transformation by the tumorigenic DNA viruses polyoma and SV40.

Preparation of radioactive Tay-Sachs ganglioside labeled in the sialic acid moiety

A procedure is described for the preparation of Tay-Sachs ganglioside specifically labeled in the sialic acid portion of the molecule. Rat brain gangliosides were labeled biosynthetically by the intracranial injection of N-acetyl-(3)H-D-mannosamine. Radioactive gangliosides were isolated and selectively degraded with bacterial neuraminidase and rat liver beta-galactosidase to Tay-Sachs ganglioside-(3)H. Radioactivity in the labeled product was confined to the N-acetyl-neuraminic acid portion of the molecule.