PubMed Health⌕ Search

Biomedical subjects

S Goto

Publications and source records attributed to S Goto.

At least 19 recordsLinked to original sources
PubMed1979

Conservation of ribosomal fidelity during ageing.

The function of ribosomes prepared from the liver of young (2--5 months old) and senescent (15--26 months old) mice were compared in vitro. The conclusions that can be drawn from the liver of senescent mice is 10 to 40% lower than that of young mice; (2) the fidelity of translation does not change grossly with age; (3) the thermosensitivity of translational activity of ribosomes and the activity of ribosome-associated ribonuclease do not change with age; (4) there is an age-dependent accumulation of free 40S ribosomal subunits in the cytoplasm of mouse liver. The relation of age-dependent changes in the structure and function of ribosomes is discussed.

Aging↗
PubMed1979

Fluorescence studies on the interaction of dansyl-L-arginine with trypsin and trypsinogen.

The enhancement of fluorescence intensity of the dansyl group due to the formation of trypsin- or trypsinogen-dansyl-L-arginine complex was measured. Dansyl-L-arginine (L-DA) is a product in the trypsin-catalyzed hydrolysis of dansyl-L-arginine methylester. Trypsinogen was found to have only one binding site for L-DA with the dissociation constant of 6.9 x 10(-3)M, which is identical with the Michaelis constant for the trypsin-catalyzed hydrolysis of dansyl-L-arginine amide (Goto, S. and Hess, G.P., unpublished results). This finding and the results of X-ray diffraction studies (1,2) suggest that this binding site is located in the active site of the enzyme. On the other hand, the active enzyme, trypsin, was found to have at least two binding sites for L-DA. One is located in the active site. The dissociation constant for L-DA bound to this site is 6.7 x 10(-3)M. The other site is probably located in the allosteric site of trypsin. The dissociation constant for L-DA bound to this site is 4.8 x 10(-4)M.

Arginine↗
PubMed1979

In vivo degradation of rat globin messenger RNA during maturation of reticulocytes.

The degradation of globin mRNA in rat reticulocytes maturing in the peripheral blood was investigated. Poly(A) and non poly(A) portions of mRNA molecules were determined quantitatively by hybridization with radioactive poly(U) and complementary DNA, respectively. During the degradation of mRNA in vivo, it was shown that (1) globin mRNA and the bulk of RNA decrease in parallel, (2) the average chain length of poly(A) segments in the mRNA does not change, (3) the percentage of poly(A) (-) globin mRNA in total globin mRNA does not change, and (4) fragments of large molecular weight do not accumulate. Possible mechanisms of degradation of globin mRNA in the reticulocytes are discussed on the basis of these observations.

Animals↗
PubMed1979

Presteady state kinetics of trypsin-catalyzed hydrolyses of dansyl-arginine derivatives.

Interactions between trypsin and each of five dansyl-arginine derivatives, dansyl-L-arginine methyl ester (L-DAME), dansyl-D-arginine methyl ester (D-DAME), dansyl-L-arginine amide (L-DAA), dansyl-L-arginine (L-DA), and dansyl-D-arginine (D-DA), are accompanied by a fluorescence intensity change which can be followed by the stopped-flow method. These compounds are substrates or products in trypsin-catalyzed hydrolysis reactions. All of these compounds, except L-DAA, show a considerable fluorescence intensity increase in the reaction with trypsin. The observed rate constant, tau obsd -1, for the initial fluorescence intensity enhancement in the reaction between trypsin and D-DAME yields a typical hyperbolic curve when the rate is plotted as a function of the ligand concentration. This result is consistent with a two-step mechanism (1) in which a fast bimolecular association process is followed by a slower unimolecular isomerization process. The isomerization process may be considered to be associated with a conformational change of the enzyme molecule, induced by the formation of the enzyme-substrate complex (1). The rate of the isomerization process depends on pH. The rates obtained for L-DAME and D-DAME increase linearly with decrease of the hydrogen ion concentration in the pH range below neutral.

Arginine↗
PubMed1979

Ceftizoxime (FK 749), a new parenteral cephalosporin: in vitro and in vivo antibacterial activities.

FK 749 is a new parenteral cephalosporin derivative which is more active against various gram-negative bacilli, including the opportunistic pathogens such as Enterobacter, Citrobacter species, and Serratia marcescens, than cephalosporins and cephamycins such as cefotiam, cefamandole, cefuroxime, cefotaxime, and cefmetazole. FK 749 was especially active against gram-negative organisms resistant to these related antibiotics. FK 749 was more potent in bactericidal activity than the other antibiotics, and the activity was clearly enhanced in the presence of 90% defibrinated rabbit blood. The therapeutic effect of subcutaneously injected FK 749 in mice infected with various gram-negative bacilli was far superior to that of cefotiam, cefamandole, cefuroxime, and cefmetazole and was almost the same as that of cefmetazole in mice infected with Staphylococcus aureus and that of ticarcillin in mice infected with Pseudomonas aeruginosa. FK 749 has, in general, nearly the same in vitro and in vivo antibacterial activities as cefotaxime. The former had more potent bactericidal activity in the presence of the blood than the latter and showed more excellent therapeutic effect than cefotaxime against infections caused by large inoculum sizes.

Animals↗
PubMed1979

Antibacterial activity of ceftizoxime (FK 749), a new cephalosporin, against cephalosporin-resistant bacteria, and its stability to beta-lactamase.

Antibacterial activity of FK 749 against ampicillin-resistant clinical isolates of Escherichia coli was compared with those of other newly developed cephalosporins. FK 749 was the most active against strains possessing R-plasmids specifying ampicillin resistance and those whose resistance was chromosomally determined. The susceptibility of ampicillin-susceptible E. coli to FK 749 was not decreased by transduction of ampicillin resistance-specifying plasmids. However, most of the transconjugants acquired a high level of resistance to cefoperazone and cefamandole and a moderate level of resistance to cefoperazone and cefamandole and a moderate level to cefotiam. FK 749 was highly stable to both penicillinase- and cephalosporinase-type beta-lactamases, including R-plasmid-mediated beta-lactamase. Its level of resistance to beta-lactamases was comparable to those of cefoxitin, cefmetazole, and cefotaxime, slightly superior to that of cefuroxime, and much superior to those of cefotiam, cefamandole, and cefoperazone.

Ampicillin↗
PubMed1979

Inhibitory effect of Pseudomonas aeruginosa on the phagacytic and killing activities of rabbit polymorphonuclear leukocytes: purification and characterization of an inhibitor of polymorphonuclear leukocyte function.

A clinically isolated strain of polymorphonuclear leukocyte (PMN)-resistant Pseudomonas was found to produce an extracellular substance (PMN inhibitor) that inhibits the phagocytic and killing activities of PMN. The PMN inhibitor was purified from culture filtrates by precipitation with (NH4)2SO4 and chromatography on phosphocellulose, diethylaminoethyl-cellulose, and Sephadex G-100. The preparation was homogenous as judged by disc gel electrophoresis. The purified PMN inhibitor appeared to be a protein with a molecular weight of approximately 65,000 that was inactivated by heating and by exposure to a proteolytic enzyme.

Animals↗
PubMed1979

Inhibitory effect of Pseudomonas aeruginosa on the phagocytic and killing activity of rabbit polymorphonuclear leukocytes: mechanisms of action of a polymorphonuclear leukocyte inhibitor.

The polymorphonuclear leukocyte (PMN) inhibitor isolated from a strain of Pseudomonas aeruginosa which is resistant to the phagocytic and killing activities of rabbit PMN inhibited migration of PMN and engulfment of latex particles by PMN. In studies of the bactericidal metabolism of PMN, the PMN inhibitor did not inhibit the intracellular activity and extracellular release of lysosomal enzymes. However, the PMN inhibitor caused a decrease of Nitro Blue Tetrazolium reduction. The PMN inhibitor had a cytotoxic effect on PMN and inhibited [14C]tyrosine uptake in intact PMN inhibitor had no inhibitory effect on protein synthesis in cell extracts.

Animals↗
PubMed1979

Comparison of antibacterial activity of a new cephalosporin, ceftizoxime (FK 749) with other cephalosporin antibiotics.

FK 749 is a distinctive new parenteral cephalosporin antibiotic with a broad antibacterial spectrum which is more potently active against a wide variety of Gram-negative bacilli, including the opportunistic pathogens such as Citrobacter and Enterobacter species and Serratia marcescens, than SCE 963, T 1551 and cefmetazole. The activity of FK 749 against Escherichia coli, Klebsiella pneumoniae, pyogenes was by far superior to that of the three other antibiotics. These test organisms were not resistant to FK 749. The antibacterial activity of FK 749 against Pseudomonas aeruginosa was almost the same as that of ticarcillin but was inferior to that of gentamicin and T 1551. The bactericidal activity of FK 749 against E. coli, K. pneumoniae and Proteus mirabilis was more potent than that of the three other antibiotics. FK 749, like cefmetazole, was extremely stable to beta-lactamases. In studies in mice, the therapeutic effect of subcutaneous injection of FK 749 against various infections due to Gram-negative bacilli was by far superior to that of SCE 963, T 1551 and cefmetazole, was almost the same as that of SCE 963 and cefmetazole against Staphylococcus aureus infection and that of ticarcillin against P. aeruginosa infection.

Ampicillin↗