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Biomedical subjects

W K Schubert

Publications and source records attributed to W K Schubert.

At least 73 records · Page 4Linked to original sources
PubMed1969

Deficient activity of dephosphophosphorylase kinase and accumulation of glycogen in the liver.

Low activity of phosphorylase and increased concentration of glycogen were found in liver tissue from five children with asymptomatic hepatomegaly. In vitro activation of liver phosphorylase in these patients occurred at the rate of 10% or less of normal. Elimination of the defect by the addition of kinase that activates phosphorylase demonstrated the integrity of the phosphorylase enzyme and the deficient activity of dephophophosphorylase kinase. On the average, 60% of the phosphorylase enzyme of normal human liver was in the active form. Phosphorylase kinase of rabbit muscle activated phosphorylase of normal human liver to a final value that was significantly higher than the one obtained in the absence of muscle phosphorylase kinase. The ultrastructural examination of hepatic tissue from the five patients revealed increased amounts of glycogen. There was scarcity of endoplasmic reticulum. There was intercellular glycogen in continuity with the glycogen of the hepatocytes through breaks in their circumference. Lipid droplets with lucid areas in the form of needles and plates contained aggregates of glycogen. There were numerous lysosomes, some containing glycogen. Large vacuoles filled with glycogen and surrounded by a membrane were seen occasionally. The vacuoles might reflect the lysosomal pathway of glycogen degradation, since there was apparent fusion of such autophagic vacuoles with small vesicles resembling primary lysosomes.

Alanine Transaminase↗
PubMed1966

Phosphorylase kinase of the liver: deficiency in a girl with increased hepatic glycogen.

Studies of a child with glycogenosis revealed an increased concentration of glycogen and low phosphorylase activity in her liver. Using mixtures of homogenates of the patient's liver and of normal liver, we found the low phosphorylase activity to be caused by a deficiency of phosphorylase kinase and not of hepatic phosphorylase. The fact that phosphorylase activity was restored to normal values by the addition of phosphorylase b kinase from rabbit muscle substantiates this conclusion.

Child, Preschool↗
PubMedDate not supplied

A comparison of liver ultrastructure in salicylate intoxication and Reye's syndrome.

All childhood liver biopsy specimens from The Cincinnati Children's Hospital Research Foundation which had been prepared for light and electron microscopy were reviewed to identify biopsies from children with salicylate intoxication. Only two cases of primary salicylate intoxication were identified. The histopathology and ultrastructural pathology were compared to that in two cases of Reye's syndrome which were selected because they had been treated with salicylates and had comparable serum salicylate concentrations at the time of liver biopsy. Liver biopsy specimens from the cases of salicylate intoxication were nearly normal by light microscopy. Lipid accumulation was minimal, and the content of glycogen and succinic acid dehydrogenase activity was normal. Mitochondria and peroxisomes appeared normal. Light and electron microscopy of liver specimens from the two cases of Reye's syndrome revealed swollen hepatocytes with microvesicular fat and central nuclei. Glycogen content and succinic acid dehydrogenase activity were diminished. All hepatocyte mitochondria were enlarged, pleomorphic, and had an expanded matrix and no mitochondrial dense bodies. The histopathology and ultrastructural pathology of liver biopsy specimens in salicylate intoxication were different from those in Reye's syndrome. In children in whom the diagnosis of Reye's syndrome is obscure, liver biopsy with electron microscopic examination is necessary for definitive diagnosis.

Child↗