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Biomedical subjects

S Kiyoto

Publications and source records attributed to S Kiyoto.

30 records · Page 2Linked to original sources
PubMed1989

WS-9659 A and B, novel testosterone 5 alpha-reductase inhibitors isolated from a Streptomyces. III. Biological characteristics and pharmacological characteristics.

WS-9659 A, a novel phenazine, produced by a Streptomyces sp., had testosterone 5 alpha-reductase inhibition activity on rat, dog and human prostates. However, WS-9659 A did not show any inhibitory activities for aldose reductase on rabbit lenses and lactate dehydrogenase on pig hearts. WS-9659 A was a competitive inhibitor against testosterone 5 alpha-reductase on rat prostates by use of testosterone as a substrate. Radio receptor binding assay of androgen receptor of rat prostates revealed that WS-9659 A had no affinity for this receptor. WS-9659 A was tested subcutaneously in immature castrated rats to confirm its effect on the growth of the ventral prostates induced by testosterone propionate.

5-alpha Reductase Inhibitors↗
PubMed1987

A new antitumor antibiotic, FR-900482. I. Taxonomic studies on the producing strain: a new species of the genus Streptomyces.

A new species in the genus Streptomyces, for which the name Streptomyces sandaensis sp. nov. is proposed, is described. Soil isolate strain No. 6897 (FERM-P 7654), produces a new antitumor substance FR-900482. The strain has a gray to red spore mass color, Rectus Flexibilis to Retinaculum-Apertum spore chain morphology, smooth spores, and is nonchromogenic. Strain No. 6897 is closely related to Streptomyces aburaviensis and Streptomyces nitrosporeus. But, there are many differences in cultural characteristics and in the utilization of carbohydrates.

Antibiotics, Antineoplastic↗
PubMed1986

A new antitumor antibiotic, chromoxymycin. I. Taxonomic studies on the producing strain: a new subspecies of the genus Streptomyces.

A new subspecies of the genus Streptomyces, for which the name S. libani subsp. rubropurpureus subsp. nov. is proposed, is described. Soil isolate, strain No. 6362, produces a new antitumor substance chromoxymycin. The strain has a gray or red spore mass color, spiral spore chains with smooth spores, is nonchromogenic, and utilizes most carbon sources. Strain No. 6362 is most closely related to S. libani, although there are differences in colorization of reverse colony and spore chain morphology between each other. Those differences are not enough to establish a new species. It is suitable to consider that strain No. 6362 is identified as a new subspecies in the species of S. libani.

Antibiotics, Antineoplastic↗
PubMed1986

A new antitumor complex, WF-1360, WF-1360A, B, C, D, E and F.

A complex of the new antitumor antibiotics (WF-1360, WF-1360A, B, C, D, E and F) was produced by Rhizopus sp. No. F-1360. Structural studies of these compounds suggested that they were novel 16-membered-ring lactones having an oxazole ring in their structures. WF-1360 was found to be identical with rhizoxin (1) and WF-1360B, C, E and F were determined to be homologues of 1 with structures 2, 3, 4 and 5, respectively. These compounds were cytotoxic when tested on P388 leukemia cells in vitro. WF-1360 was highly active against leukemia L1210 and melanoma B16. They also exhibited potent antifungal activities, but weak antimicrobial activities against some Gram-positive or negative bacteria.

Animals↗
PubMed1985

New antitumor antibiotics, FR-900405 and FR-900406. I. Taxonomy of the producing strain.

An actinomycete which was isolated from a soil sample produces new antitumor substances. The morphological and cultural characteristics of the strain resemble those of the genera Streptomyces Waksman and Henrici 1943 and Actinomadura Lechevalier and Lechevalier 1970. Cell wall composition analysis showed that strain No. 6049 contained meso-2,6-diaminopimelic acid in its cell wall, and madurose in whole-cell sugars. No sporangia, zoospores or fragmentations of vegetative mycelium are observed. From these results, strain No. 6049 is designated as Actinomadura pulveracea sp. nov.

Actinomycetales↗
PubMed1985

New antitumor antibiotics, FR-900405 and FR-900406. II. Production, isolation, characterization and antitumor activity.

The new antitumor antibiotics, FR-900405 and FR-900406, were isolated from the culture broth of Actinomadura pulveracea sp. nov. No. 6049. These compounds which contain sulfur in the molecule, represent a novel class of antitumor agents. FR-900405 and FR-900406 are highly active in mice against experimental tumors and exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi.

Actinomycetales↗
PubMed1985

Studies of an immunomodulator, swainsonine. II. Effect of swainsonine on mouse immunodeficient system and experimental murine tumor.

We examined the effect of swainsonine on antibody response to sheep red blood cells (SRBC) in immunodeficient mice which were treated with immunosuppressive factor or antitumor drugs, or inoculated with sarcoma 180 ascites tumor. The administration of swainsonine restored the capacities of the immunodeficient mice to produce antibody against SRBC. Furthermore, swainsonine inhibited completely the growth of sarcoma 180 ascites tumor in mice. Swainsonine also reduced lung metastases of B16 melanoma in mice. These results suggest that swainsonine has potential as an immunomodulator for the treatment of immunocompromised hosts.

Adjuvants, Immunologic↗
PubMed1983

Studies on WF-3161, a new antitumor antibiotic.

WF-3161 is an antitumor antibiotic produced by a strain of fungus, Petriella guttulata. The antibiotic was purified by solvent extraction and a combination of silica gel and reverse phase column chromatography. The chemical structure of the antibiotic (C31H44N4O6, mp 181-183 degrees C) was found to be a cyclic tetrapeptide consisting of phenylalanine, leucine, pipecolinic acid and 2-amino-8-oxo-9,10-epoxydecanoic acid. WF-3161 inhibited the growth of Trichophyton asteroides. It prolonged survival period of mice bearing leukemia P-388 with a high therapeutic index.

Animals↗