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Biomedical subjects

L Edelstein

Publications and source records attributed to L Edelstein.

7 recordsLinked to original sources
PubMed1977

Partition of catalase and its peroxidase activities in human red cell membrane: effect of ATP depletion.

Partititon of catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase EC 1.11.1.6) and peroxidase (donor:hydrogen-peroxide oxidoreductase EC 1.11.1.7) activities between the red cell membrane and the cytosol were studied under various experimental conditions. A small but significant amount of catalase (1.6%) was retained on human red cell membranes prepared by hemolysing washed red cells with 30 volumes of 10 mM Tris buffer, pH 7.4. Membrane -bound catalase had a relatively higher peroxidase activity than the soluble enzyme fraction. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate of the solubilized membranes demonstrated catalase to be a single band with a molecular weight of 60 000. Membranes prepared from adenosine triphosphate-depleted red cells depicted a two to three-fold increase in catalase activity, as well as an increase in 60 000 molecular weight band on polyacrylamide gel electrophoresis. The extra amount of retained catalase was a less efficient peroxidase than found in fresh membranes. The binding of catalase to ATP-depleted red cell membranes was dependent upon both pH and hemolysing ratio. Red cells incubated at pH 7.1 demonstrated a decrease in bound catalase, as did membranes prepared from red cells hemolysed at 1:100 dilution. beta-Mercaptoethanol decreased the catalase activity in the membranes and increased the odianisidine peroxidase activity without any significant effect on the 60 000-dalton band.

Adenosine Triphosphate↗
PubMed1977

Angiofibromas in tuberous sclerosis: a light and electron microscopic study.

Angiofibromas from two patients with tuberous sclerosis were studied by light and electron microscopy. Light microscopy revealed that these tumor-like nodules (which in the past have been called adenoma sebaceum) were made up of dilated capillaries, venules and arterioles embedded in connective tissue. At the ultrastructural level the arterioles embedded in connective tissue. At the ultrastructural level the endothelium of these vessels showed large numbers of microvilli on their luminal surface. The stroma contained many banded structures (so-called fibrous long spacing collagen). Myofibroblasts recently described in juvenile nasopharyngeal angiofibromas were not found in these angiofibromas of tuberous sclerosis.

Adult↗
PubMed1977

L-Dopa peroxidase activity of human erythrocyte catalase.

The human red cell hemolysate was found to have 3-(3',4'-dihydroxphenyl)-L-alanine (L-dopa) peroxidase activity. During the purification of glutathione peroxidase and catalase by ammonium sulfate precipitation, ion exchange chromatography. Sephadex gel filtration, and preparative polyacrylamide disc electrophoresis, the L-dopa peroxidase activity was found to be associated with catalase. Both sodium azide, 8 mM, and 3-amino-1,2,4-triazole, 50 mM, besides inhibiting catalase, inhibited the L-dopa peroxidase activity in each fraction. Ethylenediamine tetraacetic acid (EDTA), 4 mM, had no effect on catalase or L-dopa peroxidase activity, indicating that the oxidation of L-dopa is not a nonenzymatic process mediated by metal ions. Although the electrophoretic mobility of catalase, L-dopa peroxidase, and glutathione peroxidase are similar, a homogeneous preparation of glutathione peroxidase was free of L-dopa peroxidase activity. L-Dopa peroxidase in human red cells was co-purified with catalase.

Azides↗
PubMed1976

Lobomycosis. An electronmicroscopic, histochemical and immunologic study.

A 73-year-old woman from Guyana had nodular keloidal lesions on her face which had persisted for 56 years. A biopsy of the lesion revealed lobomycosis, a rare fungal infection. Microscopically, numerous fungi were seen in giant cells and macrophages. The macrophages had abundant pink reticulated cytoplasm. These macrophages in lobomycosis, considered by some in the past to be granular myoblastoma cells, were rich in glycoproteins and appeared to be "Gaucher-like cells" in electronmicrographs. Further, a transition of macrophages containing organisms to Gaucher-like cells was noted. Antibodies to the fungus were demonstrated in the patient's serum by counter immunoelectrophoresis and indirect immunofluorescence studies. We postulate that the Gaucher-like cells formed because of the inability of host macrophages to digest glycoproteins in the capsule of this unusual fungus.

Aged↗
PubMed1976

Giant and "granular melanosomes" in Leopard syndrome: an ultrastructural study.

Electron microscopy of lentigines was performed to study the pigmentation abnormality in two children with LEOPARD syndrome. Giant melanosomes similar to those seen in café-au-lait spots of neurofibromatosis and nevus spilus were found in a lentigine from one of our cases. Our results show that "spherical granular melanosomes" described in neurofibromatosis, are lysosomal-like structures associated with the development of complex melanin granules. Our study also demonstrates that immature melanosomes are present in some keratinocytes of LEOPARD syndrome. This finding is in contrast to the prevailing concept that only mature melanosomes are transferred to keratinocytes. The occurrence of individual melanosomes of normal size and shape in keratinocytes of skin in whites with LEOPARD syndrome, suggests that neither the size of melanosomes, nor the racial differences are the factors determining the distribution of melanosomes in keratinocytes.

Abnormalities, Multiple↗