Search PubMed⌕ Search

Biomedical subjects

K Komiyama

Publications and source records attributed to K Komiyama.

At least 163 records · Page 9Linked to original sources
PubMed1983

A new antitumor antibiotic, awamycin.

A new antibiotic, awamycin, was isolated from the culture broth of Streptomyces sp. No. 80-217. It appeared to belong to the quinone indicator group from results of physicochemical studies and has the empirical formula C38H49NO12S. This antibiotic possessed antibacterial and antitumor activities against Gram-positive bacteria and experimental murine tumors. The antibiotic also showed direct cytotoxic activity against HeLa cells in vitro.

Animals↗
PubMed1983

Studies on the biological activity of stubomycin.

Stubomycin showed direct cytotoxic activity on mammalian cells, yeast, and fungi, and rapid hemolytic activity on mouse erythrocytes. The rate and extent of the cytotoxic and hemolytic activities decreased at lower temperatures. Studies with radioactive precursors revealed that a marginal cytocidal concentration of the antibiotic inhibited synthesis of DNA, RNA, and protein of leukemic cells at almost the same rate. Stubomycin did not show any mutagenicity on mammalian cells and bacteria i.e. the induction of revertants on six bacterial strains, and chromosomal aberrations, sister chromatid exchanges, and the induction of cells resistant to 6-thioguanine on Chinese hamster cells (DON D-6). The antagonistic effect of various kinds of lipids including phospholipids, cholesterol, olive oil and squalene was studied. Significant antagonism of stubomycin against anti-Saccharomyces cerevisiae activity was observed with phospholipids except for egg lecithin and with cholesterol. The primary action of the antibiotic seems to be to change the cell surface and ultimately the lysis and death of the cells.

Animals↗
PubMed1983

Pimaricin potentiation of bleomycin activity against murine tumors.

Antitumor activity of bleomycin against Ehrlich ascites carcinoma in mice was examined in the presence and absence of a polyene antibiotic, pimaricin. A single intraperitoneal (ip) injection of bleomycin and pimaricin in combination into tumor-bearing mice on day 1 produced a synergistic life-prolongation effect as compared with that of each agent alone. Accumulation of abdominal ascites was almost completely blocked by bleomycin in combination with the tetraene antibiotic. Frequent ip injection of small doses of bleomycin and pimaricin on day 1 produced a much greater increase in life span than the single ip injection. To obtain effective synergism under these treatment schedules, it appeared that the dose of bleomycin should be reciprocally proportional to the dose of pimaricin.

Animals↗
PubMed1982

The eosinophilic and amyloid-like materials in adenomatoid odontogenic tumor.

This paper is concerned with the relationship between eosinophilic material (EM) and amyloid-like material and adenomatoid odontogenic tumors. In duct-like structures between opposing rows of tall columnar cells, EM did not stain for amyloid. Under electron microscopy, EM was composed of fibrillar and granular materials, and the fibrillar material was not amyloid. Two different kinds of EM were found in solid cell masses. Lesions from cases 2, 3, 4 and part of case 1 contained small droplet-shaped EM and these EM did not stain for amyloid. Case 1 also contained EM that stained positively for amyloid. The structure of amyloid positive EM resembled developing enamel of human tooth germs. This material was tubular and finely granular. The tubular material resembled enamel matrix fibers rather then amyloid and the fine granular material was stippled. The cells surrounding EM appeared similar to ameloblasts between secretory and maturation stages.

Adolescent↗
PubMed1982

Antitumor activity of a new antitumor antibiotic, stubomycin.

The antitumor activity of a new antibiotic, stubomycin, against various murine tumors was studied. Stubomycin showed antitumor activity against Sarcoma 180, IMC-carcinoma and Meth-A tumor. In particular, all of the mice inoculated i.p. with IMC-carcinoma were cured when they were given nine successive injections of stubomycin. Stubomycin also showed remarkable antitumor effects against Sarcoma 180 and Ehrlich ascites carcinoma when administered concomitantly with bleomycin.

Animals↗
PubMed1981

A new antitumor antibiotic, stubomycin.

A new antibiotic, stubomycin, was isolated from the culture broth and mycelia of Streptomyces strain No. KG-2245. Stubomycin was prepared as colorless plates and has the empirical formula C29H35NO5. The antibiotic possesses growth inhibitory activity against Gram-positive bacteria and transplantable murine tumors, such as Ehrlich carcinoma, and leukemia P388. The antibiotic also shows direct cytotoxic activity against HeLa cells in vitro.

Animals↗
PubMed1981

Antitumor effect of 3-[3-(2-chloroethyl)-3-nitrosoureido]-3-deoxy-D-glucopyranose on murine tumors.

The antitumor activity of a new derivative of nitrosourea, 3-[3-(2-chloroethyl)-3-nitrosoureido]-3-deoxy-D-glucopyranose (CNUG), against murine tumors was studied. CNUG showed remarkable antitumor activity against leukemias L1210 and P388, Lewis lung carcinoma, and sarcoma-180 (solid form). In particular, the majority of mice with leukemia or sarcoma-180 tumor were cured when they were given a single injection of CNUG on day 1 after tumor inoculation, and this treatment was more effective than daily treatment. CNUG was also active against sarcoma-180 grown in the brain, lung, liver or under the capsule of the kidney, and even against autochthonous lung tumor induced by 1-ethyl-1-nitrosourea. The number of peripheral leucocytes was depressed by the treatment with CNUG but this depression was less than that with 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea.

Animals↗
PubMed1981

Immunological studies on the antitumor effect of sporamycin.

The role of immunological effects in the antitumor activity of sporamycin activity of sporamycin was studied mainly using the mouse syngeneic tumor, Meth-A. Sporamycin inhibited the growth of the Meth-A tumor and Balb/c mice, and 12 out of 19 mice were cured. The 12 survivors did not show any growth of reinoculated Meth-A cells. Enzymes-histochemical observations revealed marked activities of both acid phosphatase and alpha-naphthyl acetate esterase in lymphoid cells and macrophages which heavily infiltrated the tumor tissue. Pretreatment of mice with sporamycin produced a remarkable inhibition of tumor growth. A marked neutralization activity against tumor cells was observed by Winn's method using spleen cell of tumor-bearing mice which had been pre- or post-treated with sporamycin. However, this neutralization activity was depressed by anti-Thy 1.2 serum plus complement. The response of spleen cells to concanavalin A was increased by treatment with sporamycin in mice. All of these findings suggest that sporamycin may, at least partially, act by modulating the cellular immune response.

Animals↗
PubMed1980

Histopathological studies on antitumor effect of sporamycin. Cell-mediated immunity against allogeneic tumor-bearing mice.

Mice that had received transplants of sarcoma-180 followed by treatment with sporamycin were examined histopathologically at periodic intervals. A marked degeneration of tumor cells was observed at an early stage after the administration of sporamycin, but the degeneration subsequently ceased and regrowth of the tumor was seen. Marked infiltration of lymphoid cells, granulation tissue, and fibrosis was seen in the stroma or surrounding tissue of the tumor at a late stage after the administration of sporamycin, and the regression of tumor cells became marked. With a few exceptions the mice were completely cured by about the 40th day. In the peripheral lymphoid tissues, a transitory decrease in the number of cells was observed after the administration of sporamycin, but this was followed by regeneration of the cells, followed by a marked increase in the B cell system. On the other hand, lymphoid cell depletion of the thymus had persisted. Transplantation of intact sarcoma-180 to mice preliminarily inoculated with sporamycin-treated sarcoma-180 cells resulted in inhibition of tumor growth in most of the mice, and qualitatively the same tissue reactions as those in mice cured of sarcoma-180 by sporamycin were seen. The results suggest that enhancement both of antigenicity of the tumor (cells) and of the subsequent immune response of the host by sporamycin may be involved in the cure of the experimental tumor.

Animals↗
PubMed1979

Immunological studies on sporamycin-treated animals.

Sporamycin showed a remarkable tumor regressive activity against sarcoma-180 with a single 5 mg/kg dose of intravenous administration. This antitumor effect on tumor and host animals was examined immunologically. As the results: (1) When sarcoma-180 tumor cells were used as an antigen macrophage migration inhibition reaction by spleen cells derived from the tumor-bearing mice treated with sporamycin was positive at day 7 approximately 14 after the medication and was negative thereafter. (2) The delayed hypersensitivity tested by the foot-pad reaction was positive in tumor-bearing mice treated with sporamycin, and no decrease of foot pad reaction was observed, whereas this reaction decreased remarkably in non-treated tumor-bearing mice. (3) Sarcoma-180 tumor cells were mixed with spleen cells derived from sporamycin-treated mice, and were inoculated into normal dd mice. The growth of tumor cells was inhibited markedly, but no inhibition of tumor growth was observed in case of spleen cells derived from non-treated tumor bearing mice. (4) Combined treatment of sporamycin with PS-K, an immunopotentiator, showed a remarkable synergistic effect.

Adjuvants, Immunologic↗
PubMed1979

The mode of action of a new antitumor antibiotic, sporamycin.

Sporamycin, an antitumor antibiotic, primarily inhibited DNA synthesis, while RNA and protein synthesis were not significantly affected in HeLa S3 cells. The antibiotic also caused strand scission of cellular DNA. However, the effects were not observed when the cells were incubated at 0 degrees C before washing and subsequently incubated at 37 degrees C. The Tm of calf thymus DNA decreased when incubated with sporamycin in vitro. Sporamycin did not affect DNA synthesis in vitro catalyzed by partially purified DNA polymerase alpha, beta, and gamma derived from EHRLICH ascites cells.

Animals↗
PubMed1979

Tumor development in lung of ddY mice following transplacental exposure to 1-ethyl-1-nitrosourea.

Transplacental induction of lung tumor by 1-ethyl-1-nitrosourea (ENU) was studied in pregnant ddY mice which were given a single intraperitoneal injection of 58.5 mg/kg of ENU in water between day 13 and 19 of gestation. Within 4 approximately 6 weeks after birth, pulmonary tumor nodules were found in all offsprings exposed to ENU, and they were histopathologically adenoma. Number of tumor nodules could be counted under the stereomicroscope from approximately day 40 after birth. The size of tumor increased with the lapse of time but the number of tumor nodules did not increase markedly. Weekly injections of urethan or ENU into mice pretreated with ENU in their fetal age enhanced the number of pulmonary adenoma. The development of other tumor was not seen except a few cases of lymphoma. Tumor development in the lung by injection of ENU in ddY mice during gestation is reproducible, relatively simple, and rapid. Therefore, it is considered that this may be a useful method for screening of antitumor agent.

Adenoma↗