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Biomedical subjects

S Goldfischer

Publications and source records attributed to S Goldfischer.

At least 73 records · Page 4Linked to original sources

Lysosomes in aortic smooth muscle cells. Effects of hypertension.

Hypertension induces hypertrophy and increased turnover of aortic smooth muscle cells along with an accumulation of connective tissue in the aortic wall. We identified the lysosomes in normal and hypertensive aortic muscle cells by light and electron microscopy, utilizing cytochemical staining for acid phosphatase activity. Lysosomes were found to be more numerous in hypertensive vessels. Biochemical assays of two specific lysosomal enzymes revealed a doubling of acid phosphatase and a more than threefold increase in beta-N-acetyl-glucosaminidase activities in hypertensive aortas.

Acid Phosphatase↗

Hypolipidemia in a mutant strain of "acatalasemic" mice.

Mutant "acatalasemicm" mice have an unstable catalase in hepatic and renal peroxisomnes that is readily degraded, apparently into peroxidase subunits. The hypothesis that an in situ cataloperoxidase would affect serum lipids was tested in these mutants and serum triglycerides and cholesterol were found to be significantly lower than in the wild strain. This finding is in accordance with reports that a hypolipidemic response to the injection of peroxidase subunits of hepatic catalase occurs in humans and rabbits.

Age Factors↗

Hemoglobin uptake by rat hepatocytes and its breakdown within lysosomes.

The peroxidatic activity of hemoglobin permitted visualization of its uptake by rat hepatocytes by means of the Graham-Karnovsky 3,3'-diaminobenzidine (DAB) procedure. Lysosomes were visualized by their acid phosphatase, beta-glucuronidase, and glucosaminidase activities. When large doses of rat, cow, or human hemoglobin are intravenously injected, or when hemoglobinemia is induced by injection of distilled water, DAB-positive hemoglobin is engulfed by pinocytosis. Pinocytotic vacuoles become digestive vacuoles ("phagolysosomes") by fusion with lysosomes of the dense body type that have moved from their pericanalicular position. By 16-24 hr after even massive amounts of hemoglobin (400 mg/100 g), the protein is barely demonstrable in hepatocytes. At the lowest doses of injected hemoglobin (15 mg/100 g body weight), DAB-positive vacuoles are demonstrable only in the Kupffer cells.

Acid Phosphatase↗

Lipofuscin (aging) pigment granules of the newborn human liver.

We have observed pigmented cytoplasmic granules, with the characteristic staining properties of lipofuscin (ceroid, "wear-and-tear") pigment, in newborn human liver. The pigment is found at the periphery of the lobule in hepatocytes and some bile ductular cells. It is acid-fast, PAS-positive after diastase digestion, slightly argyophilic and sudanophilic, and markedly Schmorl's- and peroxidase positive in paraffin sections. Difficult to see in sections stained with hematoxylin and eosin, the pigment can be detected in unstained sections. The granules also resemble lipofuscin found in adult tissues, in their ultra-structural and enzymatic properties. They are polymorphic, contain granular material of moderate and high electron opacity, and are delimited by a single membrane. Acid phosphatase and beta-glucuronidase activities are visualized in the newborn granules, identifying them as lysosomes. The granules also contain copper and, to a much lesser extent, iron. The accumulation of lipofuscin pigment in lysosomes in many tissues correlates well with aging, and this process has been interpreted as a reflection of cellular degeneration or wear-and-tear. However, the presence of lipofuscin granules as a constant component of neonatal liver suggests that they are not a measure of cellular senescence.

Acid Phosphatase↗