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Biomedical subjects

K Ogata

Publications and source records attributed to K Ogata.

At least 469 records · Page 26Linked to original sources
PubMed1983

The role of nuclear serine proteases in the degradation of newly synthesized histones and ribosomal proteins.

To examine whether serine proteases of rat liver chromatin are also involved in the degradation of newly synthesized and unbound ribosomal proteins and histones, like the nuclear thiol protease which we reported previously (Tsurugi, K. & Ogata, K. (1979) Eur. J. Biochem. 101, 205-213), in vivo experiments were carried out with serine protease inhibitor, PMSF. The following results were obtained. When normal rats received an intraperitoneal injection of PMSF (10 mg per 100 g body weight), nuclear serine proteases were inhibited almost completely for at least 90 min. PMSF did not affect the synthesis of proteins and RNAs of ribosomes and other subcellular fractions. The effects of PMSF treatment in vivo on the degradation of newly synthesized ribosomal proteins and histones in regenerating rat liver pretreated with a low dose of actinomycin D, which preferentially inhibited rRNA synthesis, were examined by using the double-isotope method. It was found that PMSF treatment did not affect their degradation. On the other hand, administration of E-64, a thiol protease inhibitor, to partially hepatectomized rats inhibited the degradation of those proteins markedly. From these results, it is concluded that the nuclear thiol protease, but not serine proteases, is preferentially involved in the degradation of newly synthesized ribosomal proteins and histones which are not associated with rRNA and DNA, respectively.

Animals↗
PubMed1983

Sensitive solid phase enzyme immunoassay for factor IX antigen and classification of hemophilia B.

A sensitive solid phase enzyme immunoassay (EIA) was developed for the measurement of factor IX antigen (IX:AG), using rabbit antihuman factor IX antiserum and beta-D-galactosidase, which enabled us to detect IX:AG as low as 10(-4)U/ml. 37 patients with severe hemophilia B have been investigated by EIA, inhibitor neutralization assay and bovine brain prothrombin time. They could be divided into four genetic variants. 25% had normal levels of IX:AG but decreased levels of factor IX clotting activity. On crossed immunoelectrophoresis of the hemophilia B+ and hemophilia BM, we could not find abnormalities in electrophoretic mobilities compared to normal subjects in the presence of 1 mM Ca++ lactate.

Antigens↗
PubMed1983

[Intra-arterial injection of an oily antineoplastic agent in hepatic cancer].

A lymphographic agent, Ethiodol, injected via the hepatic artery was found to remain selectively in the tumor vessels of hepatoma for a long time in our clinic. Taking advantage of this selective continuous peripheral embolization, a lipophilic high molecular anticancer agent, SMANCS (Copolymer of styrene maleic acid conjugated to Neocarzinostatin) dissolved in Ethiodol was administered via the celiac axis or the hepatic artery with Seldinger's method. Anticancer effect was examined by histological findings of specimens removed using hepatic resection (13 cases) and autopsy (1 case) in 14 patients receiving this treatment. Anticancer effect of this treatment became clear through histological findings. In the patients administered SMANCS more than 0.26 mg per 1 cm2 of maximum cut-surface area, complete or widespread necrosis of the tumor occurred, whereas non-cancerous liver tissue remained unaffected.

Adult↗
PubMed1983

The relationship of the properties of antihemophilic factor (factor VIII) that support ristocetin-induced platelet agglutination (factor VIIIR:RC) and platelet retention by glass beads as demonstrated by a monoclonal antibody.

A monoclonal antibody to human antihemophilic factor (AHF, factor VIII) was derived from BALB/c mouse spleen cells fused with P3x63Ag8 mouse plasmacytoma cells. This antibody, harvested from culture medium or ascites fluid, reacted with purified AHF and with plasmas with normal subjects or classic hemophiliacs, as measured by enzyme-linked immunosorbent assay (ELISA), but not with plasmas from patients with severe von Willebrand's disease. The antibody possessed only IgG, heavy chains and kappa light chains. It blocked ristocetin-induced platelet agglutination and, to a lesser degree, platelet retention by glass bead columns, but it did not inhibit the procoagulant activity of AHF significantly. An amount of rabbit antiserum against AHF that provided equivalent inhibition of ristocetin-induced platelet agglutination inhibited glass bead retention much more effectively than the mouse monoclonal antibody. This difference was exaggerated in studies of the corresponding Fab fragments. These data suggest that the site or sites on the AHF complex molecule that are associated with ristocetin-induced platelet agglutination differ quantitatively or qualitatively from those associated with enhancement of platelet retention by glass beads. ELISA titers of immunoreactive AHF, using the monoclonal antibody, were closely correlated to those using rabbit antiserum against AHF in normal, hemophilic, and most von Willebrand's disease plasma.

Antibodies, Monoclonal↗
PubMed1983

[Clinical and experimental studies on muscle contracture].

Concerning muscle contracture, etiology, diagnosis and treatment still remain a problem. The author examined diagnosis and treatment clinically and examined the influence of muscle fiber after intramuscular injection of some drugs. Clinical and experimental results were as follows. 1) In the diagnosis of quadriceps muscle contracture, the measurement of buttock elevation phenomenon varies according to the examiner, and in healthy people, the same phenomenon may occur. Hence, the necessity of not over-estimating the phenomenon itself should be emphasized. 2) Adult cases with deltoid muscle contracture are accompanied by pain. 3) Intramuscular injection of chloramphenicol sol on rabbit brought remarkable muscle lesion (fibrosis, lowering of phosphorylase activity) one year after ten consecutive daily injections. Intramuscular injection of chloramphenicol sol causes irreversible lesion in the muscle and this is one of the main causes of etiology of muscle contracture.

Adolescent↗
PubMed1983

Marine animal lectin-dependent tumor recognition by macrophages.

Several lectins from marine animals, such as Balanus roseus hemagglutinin, B. balanoides hemagglutinin, Tetraclita squamosa japonica hemagglutinin and Aplysia kurodai agglutinin, were tested for induction of tumor lysis mediated by macrophages. Among them, B. roseus and B. balanoides lectins agglutinated several murine tumor cells and induced binding of macrophages to tumor cells. Binding of these cells was inhibited by galacturonic acid, suggesting that carbohydrate moieties on the cell membrane of the two types of cells are recognized by these lectins. These lectins did not induce tumor lysis in co-operation with various macrophages, but after inactivation of tumor cells with glutaraldehyde, they induced extensive lysis of target cells in the presence of macrophages. B. roseus lectin was also effective in vivo. These results suggest that tumor cells can be recognized via carbohydrate moieties on the cell membrane as well as tumor-associated antigen and that some animal lectins participate in macrophage-mediated cytolysis and tumor rejection.

Agglutination↗
PubMed1982

Molecular cloning and nucleotide sequences of the complementary DNAs to chicken skeletal muscle myosin two alkali light chain mRNAs.

We report here the molecular cloning and sequence analysis of DNAs complementary to mRNAs for myosin alkali light chain of chicken embryo and adult leg skeletal muscle. pSMA2-1 contained an 818 base-pair insert that includes the entire coding region and 5' and 3' untranslated regions of A2 mRNA. pSMA1-1 contained a 848 base-pair insert that included the 3' untranslated region and almost all of the coding region except for the N-terminal 13 amino acid residues of the A1 light chain. The 741 nucleotide sequences of A1 and A2 mRNAs corresponding to C-terminal 141 amino acid residues and 3' untranslated regions were identical. The 5' terminal nucleotide sequences corresponding to N-terminal 35 amino acid residues of A1 chain were quite different from the sequences corresponding to N-terminal 8 amino acid residues and of the 5' untranslated region of A2 mRNA. These findings are discussed in relation to the structures of the genes for A1 and A2 mRNA.

Amino Acid Sequence↗
PubMed1982

Inhibitory effect of alpha-fetoprotein on protein synthesis in a reticulocyte lysate cell-free system.

The inhibitory effect of human alpha-fetoprotein on the protein synthesis (incorporation of [3H]leucine into the total protein fraction) weas observed in a rabbit reticulocyte lysate cell-free system. The incorporation was inhibited to 50% of the control level by 14-16 microM alpha-fetoprotein, and decreased to about 15% at a concentration higher than 40 microM. An almost identical dose dependence was obtained between fetal alpha-fetoprotein and hepatoma-derived alpha-fetoprotein. This inhibitory effect on the protein synthesis was due to the interference of alpha-fetoprotein to the 40 S initiation complex formation from the ternary complex (eukaryotic initiation factor 2.GTP.Met-tRNAfMet). In contrast human serum albumin purified from fetal cord sera did not exhibit this inhibition under the same conditions. These results indicate that alpha-fetoprotein may function as a regulator of the protein synthesis in the fetal stage.

Carcinoma, Hepatocellular↗
PubMed1982

Identification of the protein cross-linked to 3'-terminus of 5 S RNA in rat liver ribosomal 60 S subunits.

To cross-link the 3'-terminus of 5 S RNA to its neighbouring proteins, ribosomal 60 S subunits of rat liver were oxidized with sodium periodate and reduced with sodium borohydride. 5 S RNP was then isolated by EDTA treatment followed by sucrose density-gradient centrifugation and subjected to SDS-polyacrylamide gel electrophoresis. The protein with a slower mobility than the L5 protein, which was thought to be cross-linked 5 S RNP, was labeled with 125I, treated with RNAase, and analyzed by two-dimensional polyacrylamide gel electrophoresis, followed by radioautography. A radioactive spot located anodically from L5 protein was observed, suggesting that it is the L5 protein-oligonucleotide complex. When analyzed by SDS slab polyacrylamide gel electrophoresis followed by radioautography, the peptide pattern of the alpha-chymotrypsin digest of this 125I-labeled protein-oligonucleotide complex was similar to that of the digest of 125I-labeled L5 protein. The results indicate that L5 protein binds to the 3'-terminal region of 5 S RNA in rat liver 60 S subunits.

Animals↗
PubMed1982

Effects of ethionine treatment of protein-synthesizing apparatus of rat liver 80 S ribosomes and 40 S ribosomal subunits.

The inhibitory effects of ethionine treatment of female rats for 4 h on the protein-synthesizing machineries of 80 S ribosomes and 40 S ribosomal subunits of the liver were investigated. The following results were obtained. (1) The translation of globin mRNA by 80 S ribosomes or 40 S ribosomal subunits, in combination with mouse 60 S subunits, was markedly inhibited by ethionine treatment in a complete cell-free system containing partially purified initiation factors of rabbit reticulocytes and the rat liver pH 5 fraction. (2) The polysome formation of 80 S ribosomes in the complete system described above was inhibited by ethionine treatment. Similar inhibitions by ethionine treatment were observed in the case of incubation of 40 S subunits with reticulocyte lysate, although the polysome formation was rather low even in the case of control 40 S subunits. (3) The pattern of CsCl isopycnic centrifugation of rat liver native 40 S subunits uniformly labeled with [14C]- or [3H]orotic acid showed that the content of non-ribosomal proteins of native 40 S subunits was decreased by ethionine treatment. The analysis of proteins of native 40 subunits by SDS-polyacrylamide slab gel electrophoresis revealed that eIF-3 subunits and two unidentified protein fractions of molecular weight of 2.3.10(4) and 2.1.10(4) were decreased in ethionine-treated rate liver. (4) 40 S subunits from ethionine-treated or control rat livers were labeled with N-[3H]ethylmaleimide or N-[14C]ethylmaleimide, and the 3H to 14C ratios of individual 40 S proteins on two-dimensional polyacrylamide gel electrophoresis were measured. The results suggested that the conformation of rat liver 40 S subunits was changed by ethionine treatment. (5) These results may indicate that ethionine treatment decreases the activity of rat liver 40 S subunits for the interaction with initiation factors, especially eIF-3, as the results of conformational changes of 40 S subunits.

Animals↗
PubMed1982

Studies on the serine proteases associated with rat liver chromatin.

The chromatin fraction of rat liver exhibited proteolytic activity caused by serine proteases, with maximal activity at pH 8 or 10. They were analyzed by affinity labeling with [3H]diisopropylfluorophosphate followed by SDS-polyacrylamide gel electrophoresis, and partially purified by gel filtration through Sepharose 6B after selective extraction from the chromatin fraction. The following results were obtained. 1. The chromatin fraction contained three DFP-binding proteins with molecular weights of 52,000, 25,000, and 15,000 daltons, and they were tentatively designated proteins A, B, and C, respectively. Unlike proteins A and B, protein C reacted with DFP more strongly at pH 10 than at pH 8. A greater part of protein B was present in the nucleoli, while the others were predominantly distributed in extra-nucleolar chromatin. 2. Proteins A and B were extracted from the chromatin fraction by 5 M urea and 0.7 M NaCl, respectively; while protein C was not extractable by either solution. Proteins A and B were further purified by gel filtration through Sepharose 6B. 3. Protein B was a neutral protease with a maximal activity for 3H-labeled ribosomal proteins at pH 8 and showed high specificity for basic proteins, such as histone and ribosomal proteins. Protein A was an alkaline protease with a maximal activity at pH 10 and showed proteolytic activity not only for basic proteins but also for hydrophobic proteins, such as casein and non-histone proteins of chromatin. 4. Protein A was activated at pH 8 by high concentrations of NaCl, suggesting the presence of some inhibitor(s). Protein A was converted to protein C at pH 10, and also at pH 8 with high concentrations of NaCl. Thus, protein A is suggested to be the complex of protein C and unknown inhibitor(s). 5. When the chromatin fraction was incubated at pH 10, non-histone proteins were degraded much faster than at pH 8, although H1 histone was degraded at similar rates at both pHs. These results indicate that the chromatin fraction of rat liver contains at least two kinds of serine proteases, B and C, and that protease B is probably involved in the metabolism of basic protein, especially H1 histone. Protease C, the greater part of which associates with some inhibitors to form protein A, may play its main role in the metabolism of non-histone proteins.

Animals↗