Yoshinaka K

In vitro chemosensitivity tests on human tumor xenografts by clonogenic assay: the combined use of mitomycin C with α-interferon or γ-interferon

Using the human tumor clonogenic assay technique, the effects of Mitomycin C plus either α-interferon or γ-interferon were studied against five human tumor xenografts serially transplanted into nude mice (three gastric and two colon cancers). When the survival fraction found with the drug combination was smaller than the multiplication of survival fractions with either drug alone, the combined effect was defined as synergism. Similarly, antagonistic effect was defined when the survival fraction of drug combination was larger than the larger one observed in either interferon or Mitomycin C alone. Four out of five human tumor xenografts (three gastric and one colon cancers) showed synergistic effects in combination of α-interferon with Mitomycin C. Though two gastric cancer xenografts exhibited synergistic effects in combination of γ-interferon with Mitomycin C, antagonistic effects, which was not found in combination of α-interferon with Mitomycin C, were observed in one gastric cancer and one colon cancer xenografts.

Effects of Levamisole in adjuvant immunochemotherapy for gastric cancer; a prospective randomized controlled study.

The effectiveness of Levamisole combined with Mitomycin-C, FT-207 and PS-K for treating gastric cancer was investigated in a prospective randomized controlled study. All patients had undergone gastrectomy during the years from August 1977 to November 1980. Five year survival rates reveled no difference between groups given or not given Levamisole. In those with positive lymphode metastases plus obvious serosal invasion, there was a significant elevation in the survival rate at four years after gastrectomy. The effectiveness of Levamisole was confirmed by postoperative changes in the PPD skin test, lymphocyte blastogenesis to PHA and serum inhibition index.

Combined effects of UFT with other anticancer agents using in vivo chemosensitivity tests

In order to estimate the combined effects of UFT with other anticancer agents, a nude mouse experimental system (NMES), and a subrenal capsule assay (SRCA) were investigated. Three human tumor xenografts were serially transplanted into nude mice and examined. These were; EH-1 established from esophageal cancer, SH-6 from gastric cancer and CH-3 from colon cancer. The antiproliferative effects were estimated in accordance with the NCI therapeutic protocol. Significant antiproliferative effects were obtained only in NMES and a positive relationship was observed between the two assays (p<0.05). In the groups which were treated with a single agent, positive tumor responses were observed against mitomycin C in SH-6, against cis-DD platinum in SH-6 and EH-1, and against adriamycin in EH-1, respectively. On this study the synergistic, additive and subadditive effects were defined as the positive combined effects. The combination of MMC and UFT produced positive combined effects for all xenografts in both assays.