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Biomedical subjects

T Inui

Publications and source records attributed to T Inui.

At least 199 records · Page 11Linked to original sources
PubMed1981

Retinal sensitivity and spatial summation in the foveal and parafoveal regions.

Retinal sensitivity and the critical area of the spatial summation in the foveal and parafoveal regions were investigated by using a fundus-controlled perimeter to monitor accurately a subject's fundus picture and target position on the retina. The first experiment showed that retinal sensitivity and the critical area change continuously from fovea to periphery and that the diameter of the critical area is a linear function of retinal eccentricity. In the second experiment, this linear relationship was verified by another method.

Adult↗
PubMed1981

Studies on the effects of 3-acetyl-4"-isovaleryltylosin against multiple-drug resistant strains of Staphylococcus aureus.

The macrolide-resistance of multiple-drug resistant strains of Staphylococcus aureus was divided into two types; the decreased sensitivity of ribosomes (type I) and the decreased uptake (type II). Both types were resistant to erythromycin, tylosin and 3-acetyltylosin, and their resistance was not inducible. 3-Acetyl-4"-isovaleryltylosin inhibited the growth of both types. Protein synthesis on ribosomes of type I in vitro (S. aures MS-9610) was inhibited by 3-acetyl-4"-isovaleryltylosin, but little or no inhibition was seen with either tylosin or 3-acetyltylosin. Ribosomes of type II in vitro (S. aureus MS-8710) were sensitive to all macrolides. 3-Acetyl-4"-isovaleryltylosin accumulated about twice as much as 3-acetyltylosin in intact cell of type II.

Anti-Bacterial Agents↗
PubMed1980

Effect of adenosine-5'-triphosphate-3'-diphosphate and related nucleoside polyphosphates on the spore germination of Streptomyces galilaeus.

Exogenous addition of adenosine- and guanosine 5'-(di- and tri) phosphate 3'-diphosphate (pppApp, ppApp, pppGpp and ppGpp) at the concentration of 0.5 mM inhibits spore germination of Streptomyces galilaeus ATCC 31133. This reversible inhibitory effect appeared to be at the transcriptional level, and also depends on the phase of spore germination; pppApp inhibited more strongly RNA synthesis in the period of the germ tube emergence than the early stage of germination. No inhibitory effect was observed with normal purine and pyrimidine nucleosides, nucleotides, pApp, pGpp, cyclic AMP and pyrophosphoric acid at the concentration of 0.1 - 1.0 mM.

Adenine Nucleotides↗
PubMed1980

A radioimmunoassay for guanosine-5'-diphosphate-3'-diphosphate and adenosine-5'-triphosphate-3'-diphosphate.

A radioimmunoassay for guanosine-5'-diphosphate-3'-diphosphate (ppGpp) and adenosine-5'-triphosphate-3'-diphosphate (pppApp) has been developed. The assay method is based on competition of an unlabeled highly phosphorylated nucleotide with 3H-labeled highly phosphorylated nucleotide for binding sites on a specific antibody. Antibodies to ppGpp and pppApp were obtained by immunizing rabbits with the antigen prepared by conjugating ppGpp with human serum albumin using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and with the antigen prepared by conjugating 8-(6-aminohexyl)amino-adenosine-5'-triphosphate-3'-diphosphate with human serum albumin using glutaraldehyde, respectively. Antibody-bound 3H-labeled highly phosphorylated nucleotides were separated from the free 3H-labeled highly phosphorylated nucleotides by selective adsorption on dextran-coated charcoal. Displacement plots were linear over a concentration range of 5-1,000 pmol/assay tube in a log-probit percentage plot. Application of this method to biological systems offers improved accuracy and convenience compared with the previous 32PO4-labeling technique.

Adenine Nucleotides↗
PubMed1980

Biological properties of new acyl derivatives of tylosin.

The antibacterial activity of acyl derivatives of tylosin were examined in vitro and in vivo. The 4"-acyl group in the acylated tylosins enhanced the antibacterial activity and antimycoplasmal activity against some macrolide-resistant strains. The orally administered 3-acetyl-4" -isovaleryltylosin produced a higher blood level in mice and rabbits than tylosin and a good therapeutic effect on the infection of Staphylococcus aureus Smith in mice.

Administration, Oral↗
PubMed1980

Chemical modification of anthracycline antibiotics. I. Demethoxycarbonylation, 10-epimerization and 4-o-methylation of aclacinomycin A.

Demethoxycarbonyl derivatives of aclacinomycin A and of its 7-epimer, 10-epi-aclacinomycin A and 4-O-methylaclacinomycin A were chemically derived from aclacinomycin A. The cytotoxicity and inhibitory effects of RNA and DNA synthesis in cultured L1210 leukemia cells of the 4-O-methyl derivative approximated that of aclacinomycin A, while the demethoxycarbonyl derivatives and 10-epi-aclacinomycin A exhibited decreased activities in comparison with the parent compound.

Aclarubicin↗
PubMed1980

[Studies on the stability of aclacinomycin hydrochloride. I. Stability of solution of aclacinomycin hydrochloride (author's transl)].

Aclacinomycin is an antitumor anthracycline antibiotic isolated from the culture broth of Streptomyces galilaeus MA144-M1. In this study, the effects of heat, light and pH on the aqueous solution of aclacinomycin hydrochloride (ACM-HCl) were investigated. The following results were found: (1) The kinetic studies revealed that the thermal inactivation of ACM-HCl solution (pH 4.5) was based on the apparent first-order reaction and that Arrhenius equation was confirmed to be established between the rate constants and temperatures. When ACM-HCl solution was stored at 20, 10 and 5 degrees C, the estimated term of ACM-HCl solution at the time when the initial activity (100%) reduced to 90% residual concentration was 1.5, 6 and 12 months, respectively. (2) It was clarified by pH-log k profile that ACM-HCl solution was most stable near at pH 4.5. (3) The higher the buffer concentration was used, the faster the degradation rate, but there was no difference between the residual activity ratios at the various concentrations of ACM-HCl solution. (4) The inactivation of ACM-HCl solution under sunlight occurred in a type of zero-order reaction so that the faster inactivation rates were obtained at the more diluted concentration of ACM-HCl. (5) The major degradation products of ACM-HCl solution were 1-deoxypyrromycin (DP), MA144 S1 (S1) and bisanhydroaklavinone (F1). DP and S1 were mainly found at pH below 4.0 and F1 at pH above 5.0. The degradation under sunlight gave L1 (N-monodemethyl ACM) accompanied by the degradation of aglycone moiety in part.

Aclarubicin↗
PubMed1979

Enzymatic conversion of aclacinomycin A to Y by a specific oxidoreductase in Streptomyces.

A specific oxidoreductase converting aclacinomycin A to a new analog, aclacinomycin Y, was purified to apparent homogeneity from the culture filtrate of aclacinomycin-producing microorganisms. The isolated enzyme was a weakly acidic protein (isoelectric point, 5.9) with a molecular weight of about 72,000. The enzymatic reaction requires molecular oxygen and has a pH optimum at 5.5. The enzyme catalyzed an oxidation of the terminal sugar, L-cinerulose, of the trisaccharide moiety of aclacinomycin A to L-aculose (2,3,6-trideoxyhex-2-enopyranos-4-ulose) with removal of two electrons. Studies of substrate specificity revealed that the enzyme is an oxidoreductase capable of modifying anthracyclic triglycosides by oxidizing their terminal sugars.

Aclarubicin↗
PubMed1979

Antitumor anthracycline antibiotics, aclacinomycin A and analogues. I. Taxonomy, production, isolation and physicochemical properties.

Aclacinomycin A and B, two major components of a new antitumor antibiotic complex, and their 19 analogues were produced by a culture of strain No. MA144-M1, which was identified as Streptomyces galilaeus. They were isolated by chelation with copper ion and silicic acid chromatography, and characterized by physicochemical methods in the anthracycline group of antibiotics.

Antibiotics, Antineoplastic↗
PubMed1979

Reduction of cinerulose in aclacinomycin-A by soluble and microsomal cinerulose reductases.

The in vitro metabolism of the antitumor anthracycline antibiotic, aclacinomycin-A, was studied using rat liver homogenate. In the presence of NADH or NADPH, aclacinomycin-A was converted to aclacinomycin-A analogs, MA144 M1 and MA144 N1, which were stereospecifically reduced at the keto group of the C-4''' position of L-cinerulose in aclacinomycin-A. Subcellular fractionation indicated that the production of MA144 M1, which was reduced to L-amicetose, was catalyzed by NADPH-dependent soluble cinerulose reductase I, and the production of MA144 N1, which was reduced to L-rhodinose, was catalyzed by NADPH-dependent soluble cinerulose reductase II and NADH-dependent microsomal cinerulose reductase. The properties of these three enzymes were studied. Soluble cinerulose reductase I which produces MA144 M1 showed a optimum pH at 6.3, Km values of 3.3 x 10(-4) M for aclacinomycin-A and 3.2 x 10(-5) M for NADPH. Soluble cinerulose reductase II which produces MA144 N1 showed a pH optimum at 6.3 and Km values of 2.0 x 10(-3) M for aclacinomycin-A and 4.0 x 10(-5) M for NADPH. All thesse reductases were sensitive to sulfhydryl reagents and were inhibited by vitamin K3. Microsomal cinerulose reductase showed sensitivity to diconmarol and ferrous ion. The main nondegradative pathways of aclacinomycin-A were discussed from these results.

Animals↗