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Biomedical subjects

A Otsuka

Publications and source records attributed to A Otsuka.

At least 109 records · Page 6Linked to original sources
PubMed1981

Deletion of the 3' half of the yeast tRNA-Leu3 gene does not abolish promotor function in vitro.

The promotor function of the 3' and 5' half tRNA sequences in the yeast tRNA-Leu3 gene has been studied by in vitro transcription in Xenopus laevis germinal vesicle (GV) extracts. Truncation of the DNA template within the tRNA intervening sequence by Hpa I abolishes transcription. However, separation of the tRNA gene halves by insertion of a 300 bp DNA fragment at the Hpa I site does not affect the promoter efficiency. Further, the complete sequence of the 3' half of the tRNA is not necessary for promoter function, because removal of the 3' half of the gene by cleavage with Pvu II, within the DNA inserted at the Hpa I site, does not inhibit transcription.

Animals↗
PubMed1981

Recovery of DNA fragments inserted by the "tailing" method: regeneration of PstI restriction sites.

A general method has been developed for the recovery of any DNA fragment inserted into a cloning vehicle containing a single endonuclease PstI site. Endonuclease PstI sites are regenerated by the addition of one or more deoxyguanosine residues to the 3' termini of the PstI-cleaved vehicle by terminal deoxynucleotidyl transferase. Chain elongation by terminal deoxynucleotidyl transferase is then continued with dITP, dATP or dGTP. A plasmid vehicle, pAO1, containing a single PstI site has been constructed. Insertional (foreign) DNA fragments that were "tailed" with dCTP have been annealed to PstI-cleaved pAO1 that was "tailed" with dGTP. When the annealed fragments were used to transform competent Escherichia coli cells, the single-stranded DNA gaps in the recombinant plasmids were repaired. Plasmids recovered from transformed bacteria could be cleaved by PstI into the insertional DNA with dG:dC tracts and linear pAO1 molecules.

Base Sequence↗
PubMed1981

Ribonuclease "XlaI," an activity from Xenopus laevis oocytes that excises intervening sequences from yeast transfer ribonucleic acid precursors.

A ribonuclease (RNase) activity, RNase "XlaI," responsible for the excision of intervening sequences from two yeast transfer ribonucleic acid (tRNA) precursors, pre-tRNA(Tyr) and pre-tRNA(3Leu), has been purified 54-fold from nuclear extracts of Xenopus laevis oocytes. The RNase preparation is essentially free of contaminating RNase. A quantitative assay for RNase XlaI was developed, and the reaction products were characterized. RNase XlaI cleavage sites in the yeast tRNA precursors were identical to those made by yeast extracts (including 3'-phosphate and 5'-hydroxyl termini). Cleavage of pre-tRNA(3Leu) by RNase XlaI and subsequent ligation of the half-tRNA molecules do not require removal of the 5' leader or 3' trailer sequences.

Animals↗
PubMed1981

Fibrinolytic and plasmin inhibitor activities in patients with acute myocardial infarction.

Fibrinolytic activity and plasmin inhibitor activity were determined by Blue Dextran-fibrin method in patients with acute myocardial infarction. The normal values of fibrinolytic activity and plasmin inhibitor activity were 3.34 +/- 0.74 units and 10.10 +/- 2.39 units (mean +/- SD), respectively. The fibrinolytic activity in normal women (3.63 +/- 0.99 units) was slightly higher than that in normal men (3.17 +/- 0.79 units), but the plasmin inhibitor was not significantly different in the two sexes statistically. Neither activity varied significantly with age. The blood fibrinolytic activity was depressed in the first week after acute myocardial infarction, the decrease being maximal 3 to 4 days after the event (1.73 +/- 0.31 units). The mean plasmin inhibitor activity remained normal after acute myocardial infarction, but it was increased in 3, and decreased in 4 of 7 patients in whom it was measured 3 to 4 days after the event.

Adult↗
PubMed1978

The regulatory region of the biotin operon in Escherichia coli.

It is proposed that the biotin anabolic operon in Escherichia coli is transcribed divergently from two partially overlapping face-to-face promoters. A mutation that increases transcription in vivo creates an additional promoter in vitro. The putative operator contains an imperfect palindromic sequence that partially overlaps the promoters. The regulatory and genetic implications of these findings are discussed.

Base Sequence↗
PubMed1978

A method using fibrin-fixed Blue Dextran for determining the plasmin and plasmin inhibitor activities in human plasma.

The fibrinolytic activity of plasmin was determined by incubating with fibrin-fixed Blue Dextran as a substrate, the Blue Dextran released being proportional to the plasmin activity. The applicability of this method for rapid and accurate evaluation of fibrinolytic activity was demonstrated by dose-response curves with purified plasmin, plasmin generated by urokinase in human plasma and euglobulin. The method can also be used to determined plasmin inhibitors in plasma.

Coloring Agents↗
PubMed1978

Physicochemical properties of glycyrrhizic acid in aqueous media II: Effect on flocculation-deflocculation behavior of suspensions of sulfathiazole and graphite.

The flocculation-deflocculation behavior of sulfathiazole and graphite in aqueous solutions of glycyrrhizic acid was studied by measuring the sedimentation volume and turbidity of supernates. The dispersing effect of glycyrrhizic acid on suspension of sulfathiazole showed a maximum in the pH 3-4 region, the same pH region where the zeta-potential of sulfathiazole particles showed a negative maximum. The results were explained by the variation of degrees of ionization of glycyrrhizic acid and sulfathiazole with pH. With graphite suspensions, the pH region where the dispersing effect of glycyrrhizic acid showed a maximum shifted to a higher pH compared with sulfathiazole. This result can be attributed to the fact that graphite is a nonpolar substance so the surface properties are not affected by a pH change. Hence, the adsorption of glycyrrhizic acid occurs even in a fairly high pH range.

Adsorption↗
PubMed1978

Hypoprothrombinemia: case report.

A patient with a significant history of spontaneous and posttraumatic bleeding was found to have hypoprothrombinemia. His prothrombin (factor II) activity by clotting assay was 9.5% and his factor II antigen was 5%. Crossed immunoelectrophoresis and sucrose density gradient ultracentrifugation of the patient's plasma showed his prothrombin to be qualitatively indistinguishable from normal prothrombin by these techniques.

Adult↗