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Biomedical subjects

C Honda

Publications and source records attributed to C Honda.

50 records · Page 3Linked to original sources
PubMed1986

[Effects of cisplatin on cultured glioma cells].

Cytotoxic and cytokinetic effects of Cisplatin (cisdiamminedichloroplatinum) on cultured human and rat glioma cells (KY and C6) were studied both in vitro and in vivo. The cytotoxic or cytostatic effect was evaluated by either colony formation assay or inhibition rate of cell growth. The cytokinetic effects were analyzed by DNA histogram using a flow cytometer. It was found that the cytotoxic effect of Cisplatin on the cultured glioma cells was dose-dependent, and that human KY cells and rat C6 cells had similar sensitivity to Cisplatin. Within 24 hours after treatment of KY cells with Cisplatin, a time-dependent effect was observed, but the cytotoxic effect of Cisplatin in the medium decreased rapidly. Investigation of chronological changes in the DNA histogram of KY cells treated with 0.2 microgram/ml Cisplatin revealed that cell-cycle progression was delayed in the S-phase and blocked at the S-G2 + M boundary 18 hours later. KY tumors subcutaneously transplanted into nude mice were treated with intraperitoneal injection of 3 mg/kg/day Cisplatin for 10 days and the tumors markedly regressed by 65% of their wet weight.

Animals↗
PubMedDate not supplied

New thermal neutron capture therapy for malignant melanoma: melanogenesis-seeking 10B molecule-melanoma cell interaction from in vitro to first clinical trial.

Human melanoma regression by single thermal neutron capture therapy (NCT) using melanoma-seeking 10B compounds has been achieved. Since 1972, the aim of my team has been to synthesize tumor-seeking 10B-compounds possessing selective affinity for specific metabolic activity of the target cancer cells. Once the melanoma takes up these 10B compounds, thermal neutrons, which cause insignificant cell damage, are easily absorbed by nonradioactive 10B, inducing the 10B(n, alpha)7Li reaction and releasing the high LET particles to 14 mu melanoma cell diameter, destroying the tumor without damaging surrounding tissue. Radiobiological and preclinical studies culminated in the first successful human NCT treatment, with no recurrence of the treated melanoma since July, 1987.

Animals↗
PubMedDate not supplied

A trial to improve the analysis of boron in biological materials.

For the spectrophotometric determination of boron in biological materials, two decomposition methods were used. One is the alkali fusion method, and the other is the acid decomposition method using a uniseal decomposition vessel. A long-range calibration curve for the former method was obtained by using an ultrapure sulfuric acid. The alkali fusion method was applied to samples into which paraboronophenylalanine (BPA) or its hydrochloric salt (BPA.HCl) had been injected. By the acid decomposition method using a uniseal vessel, 50 mg dried liver was digested by a mixed solution of 1 ml conc. sulfuric acid and 6 ml 30% hydrogen peroxide. A problem exists, however, in that the hydrogen peroxide remaining in the decomposition solution must be eliminated without loss of boron.

Alkalies↗
PubMedDate not supplied

Estimation of absorbed dose in the covering skin of human melanoma treated by neutron capture therapy.

A patient with malignant melanoma was treated by thermal neutron capture therapy using 10B-paraboronophenylalanine. The compound was injected subcutaneously into ten locations in the tumor-surrounding skin, and the patient was then irradiated with thermal neutrons from the Musashi Reactor at reactor power of 100 KW and neutron flux of 1.2 X 10(9) n/cm2/s. Total absorbed dose to the skin was 11.7-12.5 Gy in the radiation field. The dose equivalents of these doses were estimated as 21.5 and 24.4 Sv, respectively. Early skin reaction after irradiation was checked from day 1 to day 60. The maximum and mean skin scores were 2.0 and 1.5, respectively, and the therapy was safely completed as far as skin reaction was concerned. Some factors influencing the absorbed dose and dose equivalent to the skin are discussed.

Aged↗
PubMedDate not supplied

Human melanoma treated by boron neutron capture therapy: comparison of the clinical response with the predicted response.

PURPOSE: A patient with malignant melanoma on the left foot was treated by thermal neutron capture therapy using 10B-paraboronophenylalanine. We compared the actual (clinical) response with the predicted response estimated using our past experimental and clinical data, and discussed some problems to be overcome in the future. MATERIALS AND METHODS: We adopted an intravenous drip infusion of the compound whereby 170 mg/kg of the drug was administered over 4-5 hours before neutron irradiation. The patient was then irradiated with thermal neutrons from the Musashi Reactor at a reactor power of 100 kW and a neutron flux of 1.0 x 10(9) n/cm2/s at the collimator surface. The total absorbed dose to the melanoma and the surrounding skin was calculated by multiplying the thermal neutron fluences by the conversion factor. RESULTS: The total absorbed doses to the melanoma and the surrounding normal skin were calculated as 19.0 and 9.4 Gy, respectively. These absorbed doses were estimated at 33.5 and 14.2 RBE-Gy, respectively, assuming that the relative biological effectiveness (RBE) of the high LET radiations was 2.0 and that each component of the mixed radiation was simply additive. The melanoma showed marked regression with mild skin reaction (dry desquamation) a month after therapy, and finally disappeared 10 months after therapy. There were no no substantial side effects. CONCLUSION: We concluded that the outcome of our calculated dose values agreed well with the clinical response and that their compatibility indicated considerable validity for our approach. However, there are still some problems-uncertainty concerning the 10B concentration in tumor and skin, determination of the total absorbed dose, and a single curative dose for malignant melanoma-to be overcome with regard to clinical use of this therapy.

Aged↗