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Biomedical subjects

M Cantz

Publications and source records attributed to M Cantz.

At least 37 records · Page 2Linked to original sources
PubMed1977

Mucolipidosis I--a sialidosis.

Mucolipidosis I is characterized by Hurler-like features and skeletal dysplasia with a cherry-red macular spot and signs of neurodegeneration involving neuronal cells and myelin. Excessive amounts of sialic acid-containing compounds were found in cultured fibroblasts, leukocytes, and urine of a patient with a clinical phenotype of mucolipidosis I. In cultured fibroblasts, profoundly diminished activity of an alpha-N-acetylneuraminidase (sialidase) was found. Mucolipidosis I thus appears to be a distinct disorder of complex carbohydrate catabolism caused by the genetic deficiency of a neuraminidase.

Cells, Cultured↗
PubMed1976

The mucopolysaccharidoses: inborn errors of glycosaminoglycan catabolism.

The mucopolysaccharidoses are genetic disorders of glycosaminoglycan metabolism. Patients with these diseases accumulate within the lysosomes of most tissues excessive amounts of dermatan and/or heparan sulfates, or of keratan sulfate. The clinical consequences of such glycosaminoglycan storage range from skeletal abnormalities to cardiovascular problems, and to motor and mental retardation. In all mucopolysaccharidoses, except Morquio disease, an excessive accumulation of sulfate-labeled glycosaminoglycans has been demonstrated in fibroblasts cultured from the patient's skin. It was subsequently shown that this was due to the deficiency of specific proteins which were named "corrective factors", because their addition to the culture medium effected a normalization of the impaired glycosaminoglycan catabolism in the respective mucopolysaccharidosis fibroblasts. The investigation of the function of the corrective factors, and other studies, led to the identification of the enzymatic defect in each of the mucopolysaccharidoses. Seven lysosomal enzyme deficiencies are now recognized among this group of disorders. A classification of the diseases, according to the mutant gene products, reveals that there is considerable phenotypic variation not only between diseases, but also within several disease types. With the availability of the appropriate enzyme assays, the previous difficulties in diagnosing these disorders have now been overcome. Methods are also available for the prenatal diagnosis, and the detection of heterozygous individuals, in most of the mucopolysaccharidoses. Although correction of the metabolic defect through enzyme replacement has been achieved in tissue culture, many problems remain to be solved before such therapy may become applicable in the patients themselves.

Glycosaminoglycans↗
PubMed1976

Prenatal diagnosis of mucolipidosis II (I-cell disease).

A pregnancy at risk for mucolipidosis II (I-cell disease) was monitored in which an affected fetus was predicted on the basis of the analyses of lysosomal hydrolases in amniotic fluid and cultured amniotic fluid cells, and by the demonstration of an excessive accumulation of [35S] sulfate-labeled glycosaminoglycans in cultured amniotic cells. This diagnosis was confirmed by performing enzyme assays and [35S] sulfate incorporation studies on material derived from the aborted fetus.

Amniotic Fluid↗
PubMed1976

The radiographic features of mannosidosis.

Skeletal changes seen in 12 patients with mannosidosis included thickened calvaria, ovoid configuration, flattening and hook-shaped deformity of the vertebral bodies, hypoplasia of the inferior portions of the ilia, and mild expansion of the short tubular bones of the hands. The pattern of skeletal changes is that of mild to moderate dysostosis multiplex with considerable intrafamilial variation. The skeletal abnormalities may decrease with age. Correlation of the skeletal abnormalities with clinical and biochemical findings is necessary for a specific diagnosis.

Adolescent↗
PubMed1975

Sandhoff disease: impaired catabolism of sulfated glycosaminoglycans in cultured fibroblasts.

Fibroblasts cultured from the skin of patients with Sandhoff disease accumulate excessive amounts of sulfated glycosaminoglycans because of degradative inadequacy. Only a slight such abnormality in the metabolism of sulfated glycosaminoglycans was seen in fibroblasts from patients with Tay-Sachs disease. The defective glycosaminoglycan catabolism in Sandhoff fibroblasts is specifically corrected by intracellular replacement of beta-N-acetyl-hexosaminidase. Both beta-N-acetyl-hexosaminidase A and B are effective in bringing about such correction, although there seem to be differences in specificity. Our findings suggest that in Sandhoff disease there is an impaired catabolism of glycosaminoglycans in addition to the defect in the degradation of glycosphingolipids.

Acetamides↗
PubMed1973

The defect in the Hunter syndrome: deficiency of sulfoiduronate sulfatase.

Skin fibroblasts cultured from patients affected with the Hunter syndrome are deficient in the activity of a protein, named the "Hunter corrective factor," that is required for degradation of dermatan and heparan sulfates. We now show that this factor, purified from human urine, removes about 2% of the sulfate residues from [(35)S]mucopolysaccharide accumulated within Hunter fibroblasts; these groups are derived from "oversulfated" regions of the polymer. Acetone-powder extracts of fibroblasts derived from patients with the Hunter syndrome are deficient in this sulfatase, in contrast to similar extracts from fibroblasts of individuals of other genotype. Hunter corrective factor coupled to alpha-L-iduronidase (or alternatively, mixed extracts from Hurler and Hunter fibroblasts) release iduronic acid from 4-O-alpha-L-sulfoiduronosyl-D-sulfoanhydromannose. We conclude that the Hunter corrective factor is a sulfatase for sulfated iduronic acid residues.

Carbohydrate Metabolism, Inborn Errors↗