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Biomedical subjects

H Okabe

Publications and source records attributed to H Okabe.

At least 559 records · Page 31Linked to original sources
PubMed1976

Purification and properties of cholesterol ester hydrolase from human aortic intima and media.

1. Cholesterol ester hydrolase of human aortic intima and media was isolated and purified about 650-fold with 10-15% recovery of the original activity by sequential precipitation with 35% acetone, gel filtration on Sephadex G-75 and DEAE-cellulose column chromatography. 2. Two pH optima of 4.5-5.0 and 7.0-7.5 were consistently observed for the partially purified cholesterol ester hydrolase of human aortic intima and media. 3. In the system used in the present study, the increasing concentration of emulsifiers, sodium taurocholate and phosphatidylcholine, inhibited the activity of the neutral enzymes but not on the acid enzymes. On the contrary, reaction products, cholesterol and oleic acid, were much more inhibitory on the acid enzymes than on the neutral ones. 4. Results of studies on the effect of presentation of substrate on the enzyme activity and on the difference between acid and neutral enzymes are also discussed.

Adult↗
PubMed1976

Acetylcholine synthesis in sympathetic human neuroblastoma.

The synthesis of acetylcholine, as well as catecholamines, was studied by assaying the activities of choline acetyltransferase (ChA) and tyrosine hydroxylase (TH) in the tumor tissues and the culture cells of human neuroblastoma. In the majority of 20 neuroblastomas of sympathetic origin, both ChA and TH activities were detected at a significantly high level. In the culture cells of five cell lines of human neuroblastoma, ChA activity was high, but TH was negative in four of the lines. However, it was observed that these enzyme activities changed significantly while in the long-term culture. ChA assay is a useful diagnostic test for neuroblastomas that synthesize acetylcholine. Future studies of neuroblastoma should consider cholinergic activity.

Acetylcholine↗
PubMed1975

Partial purification and properties of phospholipase A2 from the starfish, Asterina pectinifera.

1. Phospholipase A2 (phosphatide 2-acyl-hydrolase, EC 3.1.1.4) activity was shown to occur in the supernatant fraction of a freshly prepared homogenate from the pyloric caecum of starfish (Asterina pectinifera). 2. The phospholipase A2 has been isolated and purified 130-fold by ultracentrifugation, ammonium sulfate precipitation and column chromatographic procedures. 3. The purified enzyme was stable to heat at low pH values and the optimal pH was observed at approximately 9.0. 4. The enzyme activity was activated by Ca2+ and sodium deoxycholate, and was inhibited by EDTA.

Animals↗
PubMed1975

Murine sarcoma virus related nucleic acid sequences in a non-transforming virus derived from an interspecies pseudotype sarcoma virus.

A number of sarcomagenic viruses recovered from hamster tumors induced originally by Moloney sarcoma virus or several of its mouse pseudotypes appear to be interspecies pseudotypes with structural proteins of hamster type-C viruses and nucleic acid sequences of both mouse and hamster specificity. A non-transforming virus (GLOH-minus) recovered from a sarcomagenic virus preparation obtained from a tumor induced by the Gross pseudotype of Moloney sarcoma virus was previously shown to retain mouse sequences. The ability to discriminate readily between Gross and Moloney viruses by molecular hybridization, especially with regard to thermal stability of inter-strain hybrid molecules, and the stability of Moloney virus sequences in a rat-mouse interspecies pseudotype, made it possible to specify that the mouse virus-specific sequences in GLOH-minus are derived from Moloney virus and not Gross. Thus, even though GLOH-minus is non-transforming in vitro or in vivo, it still retains sequences highly related to Moloney sarcoma virus. The lack of transforming ability is thus probably based on loss or change of specific sequences necessary for transformation at some point in the history of this virus.

AKR murine leukemia virus↗