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Biomedical subjects

T Takeuchi

Publications and source records attributed to T Takeuchi.

At least 1,441 records · Page 80Linked to original sources
PubMed1988

Benadrostin, new inhibitor of poly(ADP-ribose) synthetase, produced by actinomycetes. I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Benadrostin, a new inhibitor of poly(ADP-ribose) synthetase was discovered in the fermentation broth of Streptomyces flavovirens MH499-O'F1. It was purified by chromatography followed by solvent extraction and then isolated as colorless prisms. Benadrostin has the molecular formula of C8H5NO4. It was competitive with the substrate, and the inhibition constant (Ki) was 34 microM.

Fermentation↗
PubMed1988

The structures of new antifungal antibiotics, benanomicins A and B.

Structures of new antifungal antibiotics, benanomicins A and B were determined to be N-[[5-[6-deoxy-3-O-(beta-D-xylopyranosyl)-beta-D-galactopyranosyloxy+ ++ ]-5, 6-dihydro-1,6,9,14-tetrahydroxy-11-methoxy-3-methyl-8,13-dioxobenzo++ + [a]naphthacen-2-yl]carbonyl]-D-alanine and N-[[5-[4-amino-4,6-dideoxy-3-O-(beta-D-xylopyranosyl)-beta-D- galactopyranosyloxy]-5,6-dihydro-1,6,9,14-tetrahydroxy-11-methoxy- 3-methyl-8,13-dioxobenzo[a]naphthacen-2-yl]carbonyl]-D-al ani ne, respectively, by spectral analyses and chemical degradation studies.

Acetylation↗
PubMed1988

Biological activities of deoxyspergualin in autoimmune disease mice.

An assessment of the prophylactic and ameliorative effects of deoxyspergualin (NKT-01), an immunosuppressive agent, was carried out in male MRL/MpJ-lpr/lpr (MRL/1) mice which spontaneously develop lupus-like lesions. When NKT-01 was administered ip daily from the age of either 8 or 19 weeks, diseases such as massive lymphadenopathy, circulating anti-DNA antibody and lupus nephritis were markedly suppressed. The primary response to lipopolysaccharide was significantly reduced in MRL/1 mice administered NKT-01 but the response to sheep red blood cells was not affected. The ability of spleen cells to release interleukins 2 and 3 with or without mitogen was significantly enhanced in mice receiving NKT-01. These findings demonstrate that NKT-01 has therapeutic activity against the development of spontaneous disease in MRL/1 mice.

Animals↗
PubMed1988

Novel antifungal antibiotics octacosamicins A and B. I. Taxonomy, fermentation and isolation, physico-chemical properties and biological activities.

Two antifungal antibiotics octacosamicins A and B were isolated from the culture broth of a strain of actinomycetes, which was identified as a strain of Amycolatopsis. These antibiotics were isolated by resin adsorption and purified by column chromatography and preparative HPLC. Both antibiotics were found to be new substances from their physico-chemical properties. They showed broad antifungal spectra.

Actinomycetales↗
PubMed1988

Novel antifungal antibiotics octacosamicins A and B. II. The structure elucidation using various NMR spectroscopic methods.

The structures of octacosamicins A and B, two new antifungal antibiotics, were studied by spectrometries and chemical modifications. The 2D NMR techniques including 1H-detected heteronuclear multiple bond correlation method were successfully applied to this study. These antibiotics have unique linear chain structure possessing N-hydroxyguanidyl group at the terminal.

Antifungal Agents↗
PubMed1988

Thrazarine, a new antitumor antibiotic. I. Taxonomy, fermentation, isolation and biological properties.

Thrazarine, O-[(3R)-2-diazo-3-hydroxybutyryl)]-L-serine, is a new antitumor antibiotic produced by Streptomyces coerulescens MH802-fF5. Thrazarine was isolated from culture filtrate by Sephadex LH-20 column chromatography and reversed phase HPLC. Thrazarine induced cytolysis of tumor cell lines co-cultured with nonactivated macrophages. This effect was tumor specific because the nontumorigenic cells were not lysed by macrophages in the presence of thrazarine. Thrazarine inhibited DNA synthesis and growth of tumor cells directly. It showed neither antimicrobial activity nor the inhibition of transamidation reactions in contrast to azaserine. Toxicities of thrazarine were much weaker than those of azaserine.

Animals↗
PubMed1988

Thrazarine, a new antitumor antibiotic. II. Physico-chemical properties and structure determination.

A new antitumor antibiotic thrazarine was soluble in water and positive to anisaldehyde-sulfuric acid and ninhydrin color reactions. The absolute structure of thrazarine was determined to be O-[3R)-2-diazo-3-hydroxybutyryl)-L-serine by acid hydrolysis, spectroscopic analysis and X-ray crystallographic analysis. Structurally, thrazarine was a new member of azaserine group antibiotics.

Antibiotics, Antineoplastic↗
PubMed1988

Synthesis and structure-activity studies of new 4''-O-acyltylosin derivatives of therapeutic interest.

Eleven 4''-O-acyltylosin derivatives were synthesized and subjected to a two-step screening system consisting of antimicrobial activity and esterase stability assays. The new derivatives were all active against macrolide-resistant Staphylococci and mycoplasmas, but only 4''-O-(4-methoxy)phenylacetyltylosin and 4''-O-(4-acetyl)phenylacetyltylosin showed better resistance to mouse liver esterase than 4''-O-phenylacetyltylosin (reference compound C).

Animals↗
PubMed1988

In vivo effects of deoxyspergualin (NKT-01) on lymphocyte activation in response to alloantigens.

We studied the effects of deoxyspergualin (NKT-01) on the events of lymphocyte activation in vivo by inoculating mice in the footpad with allogeneic spleen cells, and compared the effects with those of cyclosporin A (CyA). The administration of NKT-01 increased the numbers of cells recovered from the popliteal lymph node (PLN) 7 days after inoculation, but inhibited the proliferation of these cells in the presence of exogenous interleukin 2 (IL-2). NKT-01 enhanced IL-2 production, but suppressed the production of macrophage activating factor (MAF) in the mixed lymphocyte reaction between the PLN cells and allogeneic spleen cells treated with mitomycin C. CyA decreased the numbers of PLN cells little, and suppressed the response to exogenous IL-2 and the production of both IL-2 and MAF. Results with tumor cells used as allogeneic cells suggested that there was a close relationship between the suppression of MAF production by NKT-01 and its inhibition of allograft rejection. The findings showed that NKT-01 inhibited both the MAF production by and the response to IL-2 of PLN cells, and that these effects were involved in the suppression of allograft rejection by NKT-01.

Animals↗
PubMed1988

DNA cleavage activity of liblomycin (NK313), a novel analog of bleomycin.

Liblomycin (NK313), a novel analog of bleomycin and peplomycin (PEP), produced acid soluble DNA, base propenals and nucleo bases from isolated DNA. This was similar to the action of PEP. However, the DNA cleavage activity of NK313 was 1/2-1/10 of that of PEP in the absence of reducing agents. In the presence of reducing agents such as 2-mercaptoethanol and ascorbic acid, the activity of NK313 was stimulated more strongly than PEP. NK313 was also different from PEP in the formation and decomposition of active intermediates. This result suggested that differences in DNA cleavage activity between NK313 and PEP may be due to the different properties of their active intermediates. NK313 released preferentially pyrimidine bases from DNA, and the molar ratio of the released pyrimidine bases to the total of the released bases was little affected by the concentration of NK313 relative to DNA. In contrast, the ratio of the released purine bases by PEP increased with the concentration of PEP relative to DNA. NK313 induced double strand cleavage on pBR322 DNA as efficiently as did PEP. The major cleavage sites of NK313 on pBR322 DNA were similar to those of PEP. However, certain minor cleavage sites of NK313 were specific for NK313. Increase of PEP concentration led to increased degradation of DNA fragments; this was not the case with NK313. These results indicate that the cleavage sites of NK313 were similar to, but more limited than those for PEP.

Bleomycin↗
PubMed1988

Biological activity of the main metabolites of ubenimex in humans.

The biological activity of the two main metabolites of ubenimex in humans, (-)-N-[(2S,3R)-3-amino-2-hydroxy-4-(4'-hydroxy)phenylbutyryl]-L-leucine (OH-ubenimex) and (2S,3R)-3-amino-2-hydroxy-4-phenylbutyric acid [2S,3R)-AHPA) was examined. OH-Ubenimex was almost identical in inhibitory activity against mouse peritoneal resident macrophage aminopeptidases (APases) and the growth of IMC carcinoma in mice to ubenimex. In contrast, the inhibition of; mouse spleen cell APase activities in vitro, blastogenesis of mouse T and B cells in vitro, delayed cutaneous hypersensitivity in mice, and the growth of C1498 leukemia and HeLa S3 cells in vitro was weaker than ubenimex. Macrophage APase activity was only slightly inhibited by (2S,3R)-AHPA which also had practically no activity in the other biological assays.

Adjuvants, Immunologic↗
PubMed1988

The antiproliferative action of deoxyspergualin is different from that induced by amine oxidase.

The amine oxidase activities contained in calf serum and human serum were detected at levels of 90.8 and less than 0.1 nmol O2/minute/ml serum, respectively, by measuring oxygen consumption coupled with spermidine oxidation. Deoxyspergualin (NKT-01) and spergualin (SGL) containing spermidine in their structure were also oxidized in calf serum at the rate of 3.6 and 11.6 nmol O2/minute/ml serum, respectively. To investigate whether amine oxidase is essential for NKT-01 and SGL to exhibit their antiproliferative activities or not, the in vitro activities of NKT-01, SGL and polyamines against L1210 cells were examined in the presence of calf or human serum. Polyamines exhibited antiproliferative activity only in the presence of calf serum, while NKT-01 and SGL inhibited cell growth in the presence of both calf and human serum. In the presence of calf serum the activity of NKT-01 was inhibited by aminoguanidine, an amine oxidase inhibitor. Aminoguanidine did not inhibit the activity of NKT-01 in the presence of human serum. The activity of NKT-01 was shown at much lower concentrations in the presence of human serum than that in the presence of calf serum, and was strongly dependent on incubation time. The in vivo activities of NKT-01, SGL and SGL derivatives correlated with their in vitro activities in the presence of human serum. These results suggest that the in vivo antitumor activities of NKT-01, SGL and SGL derivatives may be attributed to a mechanism different from those of amine oxidase-oxidized product and represent a novel growth inhibitory action.

Amine Oxidase (Copper-Containing)↗