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Biomedical subjects

S Hirose

Publications and source records attributed to S Hirose.

At least 793 records · Page 44Linked to original sources
PubMed1983

Immobilization of xanthine oxidase to controlled pore-glass. Application to high-performance liquid chromatography.

Immobilized xanthine oxidase (XO) was prepared by intermolecular cross-linking to controlled pore-glass using glutaraldehyde. The performance of enzyme reactors packed with the immobilized XO were considered theoretically and investigated experimentally. Using a post-column reactor packed with the immobilized XO, simultaneous determinations of hypoxanthine and xanthine by reversed-phase high-performance liquid chromatography were achieved.

Chromatography, High Pressure Liquid↗
PubMed1983

Hepatic trisegmentectomy using the Lin liver clamp.

A new technique of hepatic trisegmentectomy, extended right lobectomy, using the Lin liver clamp was successfully performed upon five patients. Proper use of the liver clamp in hepatic trisegmentectomy seems to diminish surgical hemorrhage and to be useful in performing safe dissection of the parenchyma of the liver. Although this method is not always applicable, it is useful in selected patients.

Hepatectomy↗
PubMed1982

Increase of fidelity of polypeptide synthesis by spermidine in eukaryotic cell-free systems.

The mechanism of spermidine-induced increase of fidelity of polypeptide synthesis in a wheat germ cell-free system has been studied. It was found that the increase of fidelity in the presence of spermidine occurred mainly at the level of binding of aminoacyl-tRNA to ribosomes, that reduction of misreading was more marked at the 5'-base than at the 3'-base of the codon and that misreading caused by paromomycin and kanamycin C was not significantly decreased by spermidine. It was deduced from these results that spermidine inhibited low-frequency misreading more strongly than high-frequency misreading. In addition, spermidine was found to stimulate the rejection of non-cognate aminoacyl-tRNA mainly at an initial discrimination step during the binding of amino-acyl-tRNA to ribosomes, and slightly at a subsequent GTP-dependent discrimination step, the so-called proofreading step. In yeast, rabbit reticulocyte, and Artemia salina cell-free systems, spermidine was found to increase the fidelity of protein synthesis.

Animals↗
PubMed1982

Brain renin from bovine anterior pituitary. Isolation and properties.

Brain renin has been purified 1,670,000-fold to homogeneity from bovine anterior pituitary in seven steps, including affinity chromatography on pepstatin-aminohexyl-agarose. The molecular weight of this enzyme is 36,000 as determined by gel filtration on Ultrogel AcA 44 and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme has an isoelectric point of 5.25 and works best at physiological pH. In contrast to renal renin, bovine brain renin fails to bind to concanavalin A and four other lectins. The angiotensin I-forming activity of the purified brain renin was completely neutralized by anti-hog renal renin antibody. Rabbit antisera against pure brain renin showed a low degree of species and tissue specificity, reacting readily with hog brain renin and bovine and hog kidney renins. These results provide definite evidence for the presence of a functional brain renin-angiotensin system.

Amino Acids↗
PubMed1982

Stabilization of 30 S ribosomal subunits of Bacillus subtilis W168 by spermidine and magnesium ions.

An explanation for the fragility of 30 S ribosomal subunits of Bacillus subtilis has been studied. Degradation of 16 S ribosomal RNA, rather than degradation of ribosomal proteins, was found to cause the inactivation of 30 S subunits. Although RNAases were bound specifically to 30 S ribosomal subunits, the RNAases were able to function. Spermidine was found to contribute to the stabilization of 30 S ribosomal subunits by inhibiting the degradation of 16 S ribosomal RNA. A high concentration of Mg2+ also stabilized the 30 S ribosomal subunits of Bacillus subtilis. The polypeptide synthetic activity of 30 S ribosomal subunits prepared in the presence of spermidine was at least 4-times greater than that of 30 S ribosomal subunits prepared in the absence of spermidine; this activity was maintained without any loss for 3 months at -70 degrees C.

Bacillus subtilis↗
PubMed1982

Close association of HLA-Bw51 with Behçet's disease.

Frequency of HLA-A, B, and C antigens was studied in 184 patients with Behçet's disease to investigate the immunogenetically determined predisposition to this disease. A statistically significant increased incidence of HLA-B5 or Bw51 was noted in the patients as compared with the normal control subjects. No significant difference was observed in the distribution of other HLA antigens. On the basis of HLA studies, it seems likely that the susceptibility genes to Behçet's disease closely linked to HLA-Bw51 may have been spread by the old nomadic tribes or the Turks via the Silk Route.

Behcet Syndrome↗
PubMed1982

In vitro characterization of the fibroin gene promoter by the use of single-base substitution mutants.

A highly efficient method for segment-directed mutagenesis has been developed. The method relies on the deamination by sodium nitrite of the bases in the separated strands of a small DNA restriction fragment. The mutagen-treated strands produce transition mutations by the following sequence: (i) hybridization with the complementary strand of the wild-type DNA that had been cloned into a phage fl vector, (ii) repair synthesis in vitro, and (iii) transfection of Escherichia coli. Using this method, we have isolated 14 single-point mutants within a 31-base-pair stretch of the fibroin gene (from the T-A-T-A box at the nucleotide position -30 to the cap site at +1). In vitro transcription experiments with the HeLa cell or the silk gland cell extract show that single-base transitions at the T-A-T-A box (T to C at -30, A to G at -29, and T to C at -28) and at the -20 region (G to A at -21, T to C at -20, and A to G at -17) result in decreased promoter activities, whereas those at the cap site and the -10 regions have no effect. The initiation site of transcription is the same for five "down" (reduced activity) mutants (T to C at -30, T to C at -28, G to A at -21, T to C at -20, and A to G at -17), the cap site mutant (A to G at +1), and the wild-type genes--position +1. However, the A-to-G transition at -29 (the second base of the T-A-T-A box) induces an additional transcription start from position +4. Functions of the T-A-T-A box and the -20 regions are discussed.

Base Sequence↗
PubMed1982

Phage particle-mediated gene transfer to cultured mammalian cells.

Recombinant phage particles carrying the thymidine kinase (TK) gene of herpes simplex virus type 1, coprecipitated with calcium phosphate, efficiently transformed mouse Ltk- cells to the TK+ phenotype. The conditions necessary to achieve high efficiency of transfer of the TK gene by phage particle-mediated gene transfer were investigated. Of the parameters examined, the pH of the buffer used for coprecipitation of phage particles with calcium phosphate, the length of time of coprecipitation, and the length of the adsorption period were found to alter the transfer efficiency significantly. The optimal pH was 6.87 at 25 degrees C. The other optimal values for these parameters were as follows: coprecipitation time, 7 to 20 min; adsorption time, 18 to 30 h. Treatment with dimethyl sulfoxide, glycerol, or sucrose did not enhance gene transfer. The optimal conditions yielded about 1 transformant per 10(5) phage particles per 10(6) cells without carrier DNA. An increase in the dosage of phage particles, up to at least 5 x 10(7) phage particles per 100-mm dish, resulted in a linear increase in the number of transformants. Addition of carrier phage, up to 10(10) phage particles per dish, did not significantly affect the number of transformants.

Adsorption↗
PubMed1982

Brain renin.

Although the brain contains cathepsins at high concentrations which exhibit a non-specific renin-like activity at acidic pH, the presence of specific renin in the brain has been demonstrated by characterizing its specific properties. Renin was separated from cathepsin by affinity chromatography on casein-Sepharose. Brain renin showed neutral pH optima for the reaction to generate angiotensin I. The presence of inactive prorenin was also found. The isoelectric points of brain renin were significantly lower differences from that of renal or plasma renin. Immunohistochemical studies demonstrated a wide-spread localization of renin in many different regions. Angiotensin II, the final product of the prohormone-to-hormone conversion reaction mediated by renin and angiotensin converting enzyme, was found to exist in the same cell as renin by immunohistochemical studies of brain sections and with cloned and cultured neuroblastoma cells. This is the first demonstration of the mechanism of peptide hormone formation in neuronal cells. Similar intracellular formation was demonstrated in gonadotrophs of adenohypophysis. Coexistence of renin and angiotensin II was demonstrated in some cells. Electrophysiological studies have shown that angiotensin II functions to disinhibit the inhibition of neuronal response to electrical stimuli in the hippocampus.

Angiotensin II↗