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Biomedical subjects

H Tokita

Publications and source records attributed to H Tokita.

11 recordsLinked to original sources
PubMed1991

A newly developed in vitro chemosensitivity test (nuclear damage assay): application to ovarian cancer.

With a newly developed in vitro chemosensitivity test based on the morphological changes of nuclear damage (nuclear damage assay) described here, we were able to screen currently available anticancer drugs within 24 hr with a 100% success rate. In preclinical chemotherapy using four human ovarian epithelial tumor cell lines and their xenografts in nude mice, the in vitro/in vivo response (sensitive/sensitive and resistant/resistant) rate was 94%. The nuclear damage assay was used to determine the chemosensitivity in 49 patients (60 assays) with ovarian cancer. The response rate of the 13 patients with measurable tumors, 9 of whom showed resistance to CAP (cyclophosphamide, adriamycin, and cisplatin) therapy, was 46% when the patients were given various combination chemotherapy protocols consisting of more than one active agent selected from group A and B agents by the nuclear damage assay. The newly developed in vitro chemosensitivity test proved to be useful when selecting a second-line combination chemotherapy for patients with CAP-resistant ovarian cancer.

Animals↗
PubMed1991

[Comparative studies on the antitumor activity of fluorinated pyrimidine derivatives against human bladder, cervical and ovarian cancer xenografts in nude mice].

Fluorinated pyrimidines given orally were examined for their antitumor activity with 11 human cancer xenograft models (4 bladder, 4 cervical and 3 ovarian cancers). The drugs were evaluated to be effective when they inhibited tumor growth over 58%. UFT was not effective against all of 11 cancer xenografts tested. 5-Fluorouracil (5-FU) was effective against only one bladder cancer xenograft among 6 cancer xenografts tested. On the other hand, 5'-deoxy-5-fluorouridine (5'-DFUR) was effective against one bladder, 3 cervical and one ovarian cancer xenografts. The Antitumor activity of 5'-DFUR was correlated with the enzyme activity of pyrimidine nucleoside phosphorylase, which is an essential enzyme for phosphorolysis of 5'-DFUR to 5-FU.

Administration, Oral↗
PubMed1991

[Antitumor spectra of ranimustine against various human tumors].

Ranimustine (MCNU) has been shown to exhibit high antitumor activity and broad antitumor spectra against various experimental tumors. These effects were comparable to those of nimustine (ACNU). However, clinical applications of ACNU are indicated to various types of malignancies including solid tumors, while those of MCNU are almost limited to hematological ones. Therefore, the antitumor activity of MCNU was examined against 55 specimens from 15 types of solid tumors and compared with those of ACNU and 8 other drugs. Drug sensitivity was examined by a morphological method measuring the proportion of degenerative changes in the nucleus of drug-treated and untreated tumor cells. MCNU showed antitumor activities (measured by karyorrhexis) against adenocarcinoma of the lung, squamous cell carcinoma of the lung, renal cell carcinoma, bladder tumor, ovarian cancer and brain tumor. In addition, MCNU and ACNU showed a similar positive rate (15-16%) in this experiment and this was the highest among all drugs examined. Although MCNU and ACNU showed similar antitumor spectra, a clear difference was observed when the antitumor activities of both drugs were compared in each identical specimen. These results clearly suggest that MCNU is worthy of clinical study to examine the antitumor activity against various solid tumors.

Antineoplastic Agents↗
PubMed1991

[Result of individualized chemotherapy with a newly developed in vitro chemosensitivity testing in ovarian cancer].

By means of a newly developed in vitro chemosensitivity test based on the morphological changes in the nucleus (nuclear damage assay) as previously described, we were able to screen currently available anticancer drugs within 24 hr with a 100% success rate. The nuclear damage assay was used to determine the chemosensitivity in 50 patients (66 assays) with ovarian cancer. The response rate for the 13 patients with measurable tumors, 8 of whom showed resistance to CAP (cyclophosphamide, adriamycin, and cisplatin) therapy, was 46 percent when they were given various combination chemotherapy protocols consisting of more than one active agent selected from group A and B agents by the nuclear damage assay. The newly developed in vitro chemosensitivity test proved to be useful when selecting a second line combination for patients with CAP-resistant ovarian cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

[Basic study on in vitro chemosensitivity tests].

By means of 3 different kinds of in vitro chemosensitivity testings--(1) a nuclear damage assay developed by us, (2) MTT assay, and (3) colony formation inhibition assay--we examined the sensitivity of 8 kinds of human ovarian cancer cell lines to various anticancer drugs. The sensitivity of in vivo xenografts of the cell lines in nude mice to anticancer drugs was also examined by inhibition of the tumor growth. The in vitro--in vivo correlation of sensitivity was studied in respect to both sensitivity and specificity rates. 1. Different active anticancer drugs were screened among the 3 in vitro chemosensitivity testings in the same human ovarian cancer cell line. 2. The in vitro--in vivo correlation of the nuclear damage assay (sensitivity 50%, specificity 94%) was the highest among the 3 testings. The nuclear damage assay which we developed therefore seemed to be the most useful assay method for clinical use.

Animals↗
PubMed1985

[A new in vitro chemosensitivity test. Individualized chemotherapy against ovarian cancer and its clinical effect].

A new in vitro chemosensitivity test was developed from comparative studies on the cytotoxicity of anticancer drugs against human tumor tissues xenografted into nude mice and their cultivated cells in vitro. Half a gram of the material was sufficient to examine the sensitivity of the tissues to 10 kinds of potential anticancer drugs and the results were obtained within 24 hours. The test was applied to all of 20 patients with advanced ovarian cancer. The predictive accuracy was 58% in 12 evaluable patients. This response rate was higher than those of conventional combination chemotherapy with or without cisplatin and adriamycin. Individual ovarian cancers showed different sensitivities to the drugs. These results indicate that heterogeneity of sensitivity to anticancer drugs exists among individual ovarian cancers and that our new type of in vitro chemosensitivity test is useful for selecting the most effective drugs for each individual type of ovarian cancer.

Adult↗
PubMedDate not supplied

Antitumor activity of calcium in combination with antitumor agents against Lewis lung carcinoma.

The antitumor activity of calcium gluconate in combination with mitomycin C and 5-fluorouracil was examined against subcutaneously implanted Lewis lung carcinoma-bearing C57BL/6 mice. The mice were divided into four groups: group 1 received mitomycin C (2 mg/kg) and 5-fluorouracil (50 mg/kg) intraperitoneally once a week for four weeks beginning from the day after implantation of tumors, as well as calcium gluconate (155 mg/kg) twice a week for the same four weeks; group 2 received only mitomycin C and 5-fluorouracil; group 3 received only calcium gluconate; group 4 received a vehicle (physiological saline). Significantly enhanced inhibition of tumor growth was observed neither in a comparison between groups 3 and 4, nor in a comparison between groups 1 and 2 (expect on day 20 post implantation). Thus calcium gluconate given alone or in combination with antitumor agents hardly appeared to possess effective antitumor activity.

Animals↗
PubMedDate not supplied

Antitumor activity of ascorbic acid in combination with antitumor agents against Lewis lung carcinoma.

Antitumor activity of ascorbic acid in combination with antitumor agents (mitomycin C and 5-fluorouracil) was examined against subcutaneously implanted Lewis lung carcinoma-bearing C57BL/6 mice by feeding them an ascorbic acid-deficient diet. The mice were divided into four groups: group 1 received intraperitoneally mitomycin C (2 mg/kg) and 5-fluorouracil (50 mg/kg) once a week for four weeks beginning from the day after implantation of tumors, as well as ascorbic acid (1000 mg/kg) twice a week for the same four weeks; group 2 received only mitomycin C and 5-fluorouracil; group 3 received only ascorbic acid; group 4 received a vehicle (physiological saline). Tumor growth of group 1 compared with the other three groups, and that of group 2 compared with groups 3 and 4, was significantly inhibited by day 13 post implantation. Histological examinations of tumor tissues at 10 days after implantation of tumors already showed degenerative changes which indicated these antitumor effects.

Animals↗