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Biomedical subjects

M Owada

Publications and source records attributed to M Owada.

At least 109 records · Page 6Linked to original sources
PubMed1980

Effect of p15-associated protease from an avian RNA tumor virus on avian virus-specific polyprotein precursors.

A proteolytic activity is associated with structural protein p15 in avian RNA tumor viruses. Its effect on the known intracellular viral polyprotein precursors obtained by immunoprecipitation was investigated. Cleavage of Pr76gag resulted in the sequential appearance of p15, p27, and p19. The intracellular precursor Pr180gag-pol was also cleaved by p15, whereas the intracellular glycoprotein precursors of avian RNA tumor viruses, Pr92env, remained unaffected by p15 under all conditions tested. The specificities of the antibodies used to precipitate the precursors influenced the pattern of intermediates and cleavage products obtained by p15 treatment. If virus harvested from the the Prague strain of Rous sarcoma virus, subgroup C-transformed cells at 15-min intervals was incubated at 37 degrees C for further maturation, RNA-dependent DNA polymerase activity showed an optimum of DNA synthesis with 70S viral RNA or synthetic template-primers after short incubation periods. The presence of additional p15 during incubation resulted in a shift of the enzyme activity peak toward earlier time points. Virus harvested at 3-h intervals contained significant amounts of Pr180gag-pol and Pr76gag. The addition of p15 resulted in the cleavage of Pr180gag-pol and Pr76gag, but only a few distinct low-molecular-weight polypeptides appeared. Treatment of purified RNA-dependent DNA polymerase with p15 in vitro resulted in a disappearance of the beta subunit and an enrichment of the alpha subunit. In addition, a polypeptide of 32 x 10(3) molecular weight was generated. The cleavage pattern observed differed from the one obtained by trypsin treatment.

Animals↗
PubMed1980

Biologic and therapeutic effects of 1 alpha-hydroxycholecalciferol in different types of Fanconi syndrome.

The plasma 1,25-(OH)2VD3 level in Fanconi syndrome was low but rose rapidly following the administration of 1 alpha-OHVD3. 1 alpha-OHVD3 was administered to 6 patients with different types of Fanconi syndrome. The effect of 1 alpha-OHVD3 proved to be 200-250 times as great as that of vitamin D2. From our results it was suggested that Ca malabsorption due to failure of 1 alpha-hydroxylation of vitamin D in the kidney, together with renal tubular acidosis and hypophosphatemia, is involved in the pathogenesis of the rickets of Fanconi syndrome.

Adolescent↗
PubMed1978

In utero diagnosis of Gaucher disease.

Beta-Glucosidase activity measured by synthetic substrate at pH 4.6 was low in the cultured amniotic cells from two pregnant women at risk for juvenile and adult type Gaucher disease. The diagnosis was confirmed by showing a low activity of beta-glucosidase in the skin fibroblasts with a synthetic substrate or in the spleen with a natural substrate, and by ascertaining the presence of Gaucher cells in the fetal tissues. However, considerable activity of beta-glucosidase measured with synthetic substrate was found in the liver of both affected fetuses and in the spleen of one. It is advisable that the determination of beta-glucosidase to confirm prenatal diagnosis of Gaucher disease be done either in the cultured skin fibroblasts or in the spleen, and if in the spleen, with a natural substrate rather than a synthetic one.

Amniocentesis↗
PubMed1977

Adenylate cyclase activity and the cAMP level are not directly correlated with transformation by avian sarcoma viruses.

The adenylate cyclase activity was measured in chick embryo fibroblasts (CEF) infected with temperature-sensitive mutants (ts) of avian sarcoma virus (ASV). When CEF transformed with a (ts) mutant at 36 degrees C were incubated at the non-permissive temperature (41 degrees C), recovery from the low adenylate cyclase activity detectable in the transformed state was slower than the disappearance of signs of morphological transformation. After a downward shift of the temperature the activity decreased and this change was also slower than the alteration of cell morphology. The affinity of the enzyme system for ATP also changed after, and not during, morphological alteration. No significant difference was observed between the cAMP levels in ASV-transformed and non-infected CEF. These findings are consistent with the idea that adenylate cyclase is not involved in cell transformation and that the change in its activity is secondary to cell transformation.

Adenylyl Cyclases↗
PubMed1977

Neuropathic Gaucher's disease with normal 4-methylumbelliferyl-beta-glucosidase activity in the liver.

beta-Glucosidase activity was measured in control subjects and in five patients with neuropathic Gaucher's disease. In three patients with Gaucher's disease, methylumbelliferyl- and p-nitrophenyl-beta-d-glucopyranoside (4MU- and PNP-beta-glucosidase) activity was almost normal in the liver but markedly reduced in the spleen and fibroblasts. In the other patients with Gaucher's disease 4MU- and PNP-beta-glucosidase activity was also very much reduced in the liver, spleen, and fibroblasts. DEAE-cellulose column chromatography with a chloride gradient elution of the liver extract from a control subject and from two patients with Gaucher's disease, exhibiting normal 4MU- and PNP-beta-glucosidase activity, revealed the presence of two peaks of 4MU- and PNP-beta-glucosidase activity (fractions 1 and 2). pH activity curves of beta-glucosidases and Km measured with 4MU-beta-glucoside in fractions 1 and 2 from patients with Gaucher's liver were identical to those from the control liver. However, fractions 1 and 2 from infantile Gaucher's liver exhibited no activity measured with glucocerebroside whereas those from juvenile Gaucher's liver showed a considerable activity. Glucocerebroside was greatly accumulated in the liver, even though an almost normal activity of 4MU-beta-glucosidase was detected in three of the five patients studied.

Cerebrosides↗
PubMed1976

[Intracranial hemorrhage in an infant due to vitamin K deficiency --successful management of spontaneous intracerebral and subjural hematoma].

A one-month-old male infant with spontaneous intracerebral and subdural hematomas due to vitamin K deficiency was described. He was breastfed. Loose stools continued and began to contain blood. He had fever, vomiting and convulsion, and became drowsy. The blood studies showed anemia and hypoprothrombinemia. Left carotid angiograms revealed intracerebral and subdural hematomas. He was treated successfully by immediate operation and administration of vitamin K. 2) Vitamin K deficient hemorrhage beyond the immediate newborn period was discussed with reference in the literature. Three etiologic factors included, decreased vitamin K intake, decreased intestinal absorption of vitamin K and decreased production of vitamin K by colon bacteria. The most important factor of the three seemed to be low vitamin K intake. Intracranial hemorrhage was recognized in about one third of the cases in the literature. It was emphasized that vitamin K deficiency occurring beyond the immediate newborn period was very important as a cause of intracranial hemorrhage in infancy.

Cerebral Hemorrhage↗