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Biomedical subjects

K Komiyama

Publications and source records attributed to K Komiyama.

At least 109 records · Page 6Linked to original sources
PubMed1989

Novel cytocidal antibiotics, glucopiericidinols A1 and A2. Taxonomy, fermentation, isolation, structure elucidation and biological characteristics.

Two novel antibiotics, glucopiericidinols A1 (1) and A2 (2) were isolated from the cultured broth of Streptomyces sp. OM-5689. The structures of these two compounds were deduced employing spectroscopic analyses. These antibiotics showed potent cytocidal activities against HeLa S3 cells in vitro (MIC 1: 0.39 microgram/ml, 2: 0.10 microgram/ml) when the cells were exposed to the antibiotics for 3 days. Although 1 and 2 showed no activity at 1,000 micrograms/ml against various Gram-positive and Gram-negative bacteria, yeast or fungi, they did have inhibitory activity against Piricularia oryzae (MIC of 1: 125 micrograms/ml, of 2: 31 micrograms/ml).

Aminoglycosides↗
PubMed1989

Chemical modification of hitachimycin. II. Synthesis and antitumor activities of carbonate derivatives.

Several carbonate derivatives of hitachimycin have been synthesized and evaluated their activities including antibacterial, cytocidal against HeLa cells and in vivo antitumor against Sarcoma 180. Some of these derivatives showed higher antitumor activity than hitachimycin. Among the derivatives, 11,15-di-O-methoxycarbonylhitachimycin (2), 11,15-di-O-ethoxycarbonylhitachimycin (3) and 15-O-methoxycarbonylhitachimycin (9) were most effective in in vivo assay.

Animals↗
PubMed1989

[Potentiation of the therapeutic effect of chemotherapy and hyperthermia on experimental tumor and reduction of immunotoxicity of mitomycin C by juzen-taiho-toh, a Chinese herbal medicine].

Potentiation of the therapeutic effects of chemotherapy and local hyperthermia by the Chinese herbal medicine, Juzen-Taiho-Toh (JTX, TJ-48), was studied using murine tumours. Mouse sarcoma 180 tumor cells were inoculated s. c. into the footpads of ICR mice. TJ-48 was given (days 1-50) orally. On appropriate days (days 5, 8, 12, 15 and 19), mice were administered mitomycin C (MMC, 3 mg/kg/day) and treated with hyperthermia (43 degrees C, 30 min). TJ-48 markedly potentiated the effects of the combined use of MMC and hyperthermia. Similar results were observed against B16 melanoma inoculated into BDF1 mice. Tumor-bearing feet of mice treated with MMC (days 5, 8, 12, and 15) and TJ-48 (days 1-40) were amputated on day 14, the S180 tumor was reinoculated sc into the axillary region on day 19, and the subsequent tumor growth was observed. These results indicated that tumor growth and the incidence of tumors in the nontreated group were suppressed. However, a marked tumor growth was observed in the group administered MMC. In contrast, tumor growth and the incidence were suppressed in the group given MMC plus TJ-48 when compared with MMC alone. These results suggest that TJ-48 not only potentiates the combined effects of MMC and hyperthermia but also reduces and/or eliminates the immunotoxicity of MMC in the host.

Animals↗
PubMed1988

Role of hepatocytes in the uptake of IgA and IgA-containing immune complexes in mice.

The role of parenchymal and nonparenchymal mouse liver cells in the uptake of polymeric IgA (pIgA) and pIgA-containing immune complexes (IC) of low mol. wt (less than 1 x 10(6)) was studied. As detected by immunofluorescence and immunoelectron microscopy, pIgA were bound on the surface of isolated hepatocytes. Following the injection of radiolabeled pIgA or pIgA-IC into mice, the total radioactivity recovered from isolated liver cells was preferentially associated with parenchymal cells. The ability to inhibit the transport of pIgA and pIgA-IC by pIgA of an irrelevant specificity suggests that pIgA-IC and pIgA are bound and transported by the same mechanism. These results indicate that mouse hepatocytes are involved in the uptake and hepatobiliary transport of pIgA and pIgA-IC of low mol. wt.

Animals↗
PubMed1988

Immunoglobulin subclasses in chronic tonsillitis.

The distribution and proportion of immunoglobulin-producing cells in palatine tonsil, including IgG and IgA subclasses, have been examined in chronic tonsillitis using an immunofluorescence method. Results obtained indicate that the percentage ratios of IgG1:IgG2:IgG3:IgG4 were 53.1:35.9:4.7:6.3. Higher percentages of IgG1- and lower percentages of IgG2-producing cells were found among 3 types of tonsillitis. Proportional ratios of IgA1:IgA2 were approximately 80:20, and a slight elevation of IgA2-producing cells was observed in chronic tonsillitis.

Antibody-Producing Cells↗
PubMed1988

HNK-1+ (Leu-7) cells and natural killer cell activity in inflamed human gingival tissue.

The presence of HNK-1 (Leu-7)-positive cells and natural killer (NK) cell activity was determined in human periodontal tissues. Gingival tissues obtained from 25 adult patients were processed for analysis utilizing a HNK-1 (Leu-7) mouse monoclonal antibody. A subpopulation of non-adherent lymphoid cells obtained by collagenase digestion of inflamed gingival tissues from 10 patients was examined for the presence of large granular lymphocytes (LGL) by May-Grünwald-Giemsa staining and for NK cell activity against K562 cells by a 51Cr release cytotoxicity assay. HNK-1+ cells were identified in gingival tissue sections of 21 patients, and were present in or close to discrete foci of plasma cells. HNK-1+ cells were scarce in mildly inflamed or uninflamed tissues sections. LGL were identified in 9 of 10 gingival single-cell suspensions and constituted approximately 5% of the gingival cell population. NK cell-mediated cytolysis, at varying effector/target cell ratios, was observed for 3 of 4 enriched gingival mononuclear cell populations. Gamma-interferon (INF-gamma) preincubation of enriched gingival effector cells from 5 additional patients resulted in a 43% increase in NK cell activity. The finding of increased HNK-1+ cells with gingival inflammation suggests that these cells may play a role in tissue damage, as well as in modulation of B cell activity, in gingivae of patients with periodontal disease.

Adult↗
PubMed1988

Glycogen synthetic and degradative activities by Actinomyces viscosus and Actinomyces naeslundii of root surface caries and noncaries sites.

The relative glycogen synthetic and degradative activities of Actinomyces viscosus and Actinomyces naeslundii, freshly isolated from root surface caries and noncaries sites, were compared. The glycogen synthetic activity was measured by incubating glucose-(or sucrose-)grown resting cells with 100 mM glucose (or sucrose) and U-[14C]-glucose (or U-[14C]-sucrose) on a pH-stat maintained at 5.0, 6.0, and 7.0 for 1 h under anaerobic conditions. For the glycogen degradation assays, after the 1-hour incubation period, the cells were reincubated under similar conditions, but in the absence of external carbon sources. Carbohydrate utilization and total acid formation were also monitored. Both the glucose- and sucrose-grown cells of A. viscosus and A. naeslundii strains originating from root surface caries lesions synthesized approximately twice as much glycogen as the strains of noncaries origin. Although there were significant differences in the rates of glycogen synthesis, the rates of glycogen degradation were essentially the same for the Actinomyces strains from both caries and noncaries sites. However, the time required for glycogen degradation by the strains from caries sites was much longer. This study suggests that the abilities of A. viscosus and A. naeslundii originating from root surface caries lesions to synthesize large amounts of glycogen and to degrade this stored polymer slowly under conditions of starvation, particularly in an acidic environment, may be one of the factors contributing to the cariogenic potential of these organisms in root surface caries.

Actinomyces↗
PubMed1988

The effect of kazusamycin B on the cell cycle and morphology of cultured L1210 cells.

The effect of a potent antitumor antibiotic, kazusamycin B, on the cell cycle of L1210 cells was examined. Kazusamycin B arrested synchronized L1210 cells at G1 phase. Retardation of metaphase initiation was also observed. Flow cytometric analysis of kazusamycin B-treated asynchronized cells also confirmed G1 arresting effect of kazusamycin B. In addition, an unidentified cell population with lower fluorescence intensity than G1 population was observed when the cells were exposed to the drug longer than 12 hours. Morphology of kazusamycin B-treated L1210 cells revealed that the intranuclear structure changed within 4 hours, and that abnormal condensation of nuclei coincided with the appearance of unidentified population. Kazusamycin B inhibited RNA synthesis moderately but specifically at 2 hours. However, this inhibition might be a secondary effect of the antibiotic-induced structural abnormality of the nuclei.

Animals↗
PubMed1988

Chemical modification of hitachimycin. Synthesis, antibacterial, cytocidal and in vivo antitumor activities of hitachimycin derivatives.

Several acyl derivatives of hitachimycin have been synthesized and their activities, including antibacterial, cytocidal against HeLa cells and in vivo antitumor against sarcoma 180, evaluated. Some of these derivatives showed higher antitumor activity than hitachimycin. Among the derivatives, 11-O-propionyl-15-O-butyrylhitachimycin (12) and the 11-O-acylhitachimycins (15-17) were most effective in in vivo assay.

Acylation↗
PubMed1988

[Potentiation of chemotherapeutic activity by a Chinese herb medicine juzen-taiho-toh].

Antitumor activity of Juzen-Taiho-Toh (JTX) and combination effect of JTX with antitumor agents were studied using murine tumors. In order to determine the antitumor activity of JTX, mice inoculated ip with IMC carcinoma (1 X 10(6) cells/CDF1 mouse), sarcoma-180(1 X 10(6) cells/ICR mouse) or Meth-A fibrosarcoma (1 X 10(6) cells/BALB/c mouse) were treated with JTX (12.5-50 mg/kg/day) ip on day 1 through day 10, and the survival days of mice were examined. Treatment with 25 mg/kg/day produced 38.7% increase of life span against IMC carcinoma. However, no antitumor effect was observed on solid form of these tumors by the daily treatment with JTX. Combination effect of JTX and antitumor agents was also examined. ICR mice inoculated sc with 1 X 10(6) cells of sarcoma-180 on day 0 were treated with JTX (2,000 mg/kg/day) po on day-7 through day 30. In addition, some of these groups received mitomycin C (5 mg/kg), cytoxan (67 mg/kg) or adriamycin (2.5 mg/kg) iv on days 3, 8 and 11, and the size of tumor grown in sc site was measured by a caliper. In combination with JTX, mitomycin C resulted in a significantly greater tumor growth inhibition than could be obtained with mitomycin C alone. Secondly, BALB/c or C57BL/6 mice inoculated sc with 1 X 10(4) cells of Meth-A fibrosarcoma or 1 X 10(5) cells of B16 melanoma on day 0 were treated with JTX (2,000 mg/kg/day) po on day 1 through day 30. Some of these group received ip with mitomycin C (3 mg/kg), adriamycin (2 mg/kg), 5-FU (33 mg/kg) or cytoxan (67 mg/kg) on days 3, 6, 9, 12, 15 and 18. From this result, the group treated with JTX and mitomycin C also showed a higher tumor-growth inhibition. Thus, a combination of a high dose of mitomycin C with JTX was more effective than mitomycin C alone.

Animals↗