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Biomedical subjects

E F Neufeld

Publications and source records attributed to E F Neufeld.

At least 109 records · Page 6Linked to original sources

The defect in the Hurler and Scheie syndromes: deficiency of -L-iduronidase.

Skin fibroblasts cultured from patients affected with the Hurler or Scheie syndromes (mucopoly-saccharidoses I or V, respectively) have a functional deficiency of a protein required for catabolism of sulfated mucopolysaccharide that has been designated the "Hurler corrective factor." We now show Hurler factor purified from normal human urine to be associated with alpha-L-iduronidase activity. Cell lines deficient in Hurler corrective factor have no detectable activity of alpha-L-iduronidase (less than 3% of that found in cells from individuals of other genotypes). Such correspondence indicates that Hurler corrective factor and alpha-L-iduronidase are the same entity. Correction of deficient cells is accompanied by an efficient uptake of alpha-L-iduronidase from the medium.

Carbohydrate Metabolism, Inborn Errors↗

Simulation of genetic mucopolysaccharidoses in normal human fibroblasts by alteration of pH of the medium.

Catabolism of sulfated mucopolysaccharide by normal human fibroblasts in culture is progressively inhibited as the pH of the growth medium is raised from 6.8 to 8.0. The final cell density increases with the change in pH. The capacity to degrade mucopolysaccharide is rapidly restored by lowering the pH, and this reactivation does not require protein synthesis. Such pH dependence is not observed in cells from patients with genetic impairment of mucopolysaccharide degradation, such as the Hurler or Hunter syndromes. These results may have relevance not only to studies of mucopolysaccharide metabolism in cell culture, but also to the use of metachromasia as a genetic marker and to the observation that normal fibroblasts are released from contact inhibition of growth as the pH of the growth medium is raised.

Carbohydrate Metabolism, Inborn Errors↗

The defect in Hurler and Hunter syndromes. II. Deficiency of specific factors involved in mucopolysaccharide degradation.

Cultured fibroblasts, derived from patients with the Hurler and Hunter syndromes, show defective degradation of sulfated mucopolysaccharide. The aberrant metabolism of Hurler cells can be corrected by secretions of fibroblasts of genotype other than Hurler, and similarly, the defect of Hunter cells can be corrected by secretions of fibroblasts of genotype other than Hunter. The active factors in these secretions, which are heat labile and associated with macromolecules, accelerate the degradation of mucopolysaccharide.

Culture Techniques↗

Hurler and Hunter syndromes: mutual correction of the defect in cultured fibroblasts.

The biochemical defect of cultuired skin fibroblasts from Hurler or Hunter patients (faulty degradation of sulfated mucopolysaccharide, resulting in excessive intracellular accumulation) may be corrected if cells of these two genotypes are mixed with each other or with normal cells. The effect is mediated by substances released into the medium.

Carbohydrate Metabolism, Inborn Errors↗