The thermodynamic or Arrhenius analysis for lethal effect on normal cells and thermotolerant cells were undertaken in Chinese hamster ovary cells. Heat treatment at 44°C for 30min was chosen as the priming heat dose to develop thermotolerance that reached a maximum by 14 hours of incubation after the priming dose. The survival curves for normal (non-thermotolerant) and thermotolerant cells were obtained at 42 to 45°C with various treatment times. Mean lethal dose, D_o, was calculated from each survival curve, and the reciprocals of these Do values were plotted as a function of the reciprocal of the absolute temperature (Arrhenius plot). Arrhenius analysis for single-heated cells showed a breaking point at 43°C with inactivation energies of 172±20 above and 348±76kcal/ mole below the point. Arrhenius analysis for thermotolerant cells revealed no breaking point in the temperature range studied (42 to 45°C) with an inactivation energy of 212±20kcal/mole. Possible reasons for the breaking point at 43°C in the Arrhenius plot for normal cells, differences in the inactivation energies of normal cells below and above 43°C, and the inactivation energy of thermotolerant cells are discussed.

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This report analyzes 355 cases of esophageal cancer registered in the Department of Radiology, Hyogo College of Medicine between May 1980 and June 1989. Of these cases, 31 (8.7%) had multiple primary malignant neoplasms. Digestive tract cancer accounted for 66% of the total; primary malignant neoplasms other than esophageal cancer included 15 cases of stomach cancer, and 6 cases of colon cancer. There were followed by five cases with cancer of the head and neck. The cancers were metachronous in 18 sites, and in 16 of these 18 sites, other cancer occurred first. Synchronous neoplasms occurred in 14 sites. In the future, diagnosis of multiple primary cancers should increase considerably concomitantly with improvement in the prognosis of esophageal cancer, and it will be necessary to carefully observe a patient for the onset of multiple primary cancers, especially in long-term survivors.

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This is a retrospective analysis of 19 patients with carcinoma of the cervical esophagus (Ce) and 36 of the upper thoracic esophagus (Iu) treated with radiotherapy between September 1977 and December 1987. Three-year survival rates by Kaplan-Meier method were 18% in Ce cancer and 7% in Iu cancer. Two-year local tumor control was obtained in 3 Ce and 4 Iu cancer. Concerning the treatment methods for the above 7 patients, 3 patients with carcinoma of the Ce were treated with double wedged technique and 4 of Iu were treated with box-technique (2 patients) rotation technique (1) and double wedge technique (1). There were no 2-year local tumor control in patients who received less than 60Gy of the tumor dose or whose tumor exceeded more than 10cm in length. Double wedge technique is suitable for radiotherapy of Ce cancer, while further investigation of dose and compensation is necessary for Iu cancer.

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A human malignant glioma was subcutaneously transplanted into nude mice and locally irradiated. The histologic characteristics of tumors seriallytransplanted into mice were comparable to typical glioblastoma. Inhibition of tumor growth was significant (p<0.01) in mice that received more than 500R radiation, especially in those that received 1000-3000R. Though viable tumor cells were found in all mice regardless of radiation dose or degree of tumor regression, increase in cellular pleomorphism and number of GFAP-positive cells were seen more frequently in irradiated tumors. The percentage of S-100 protein positive cells did not vary significantly.

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Between 1962 and 1975, 192 patients with carcinoma of the mobile tongue were treated with radium interstitial radiotherapy, and 105 survived for five years without local recurrence. There was recurrence in the vicinity of the initial primary cancer in 16 of the 105 patients (15.2%) more than five years after the initial treatment. The site of recurrence was the homolateral side of the tongue in six patients, the contralateral side in six, and adjacent tissue in four. The treatment for recurrence was surgery, radiotherapy, and cryosurgery combined with radiotherapy in ten, four and two patients, respectively. The five-year survival rate after treatment of late recurrence was 59%, which was comparable to that after initial treatment for all patients (63%), and was significantly better than that after secondary treatment for recurrence that developed before five years (32%). One lesion of a different histological type than the initial primary cancer was diagnosed, with a high level of reliability, as radiation-induced cancer. The other late recurrences were considered clinically to be second primary cancers.

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Sixty-one patients with squamous cell carcinoma of the tongue received ¹³⁷Cs implants at Tokai University Hospital from 1978 through 1987. In 53 cases, the neck regions including the primary lesions were treated with external irradiation at doses of 5.1-54.1Gy. Total dose to the primary lesion was 50-120Gy. Twenty patients also received chemotherapy. Relapse-free local control at 2 years was 47/61 (77%). Thelocal control rate was similar at various T stages: T₁, 13/15 (87%); T₂, 28/38 (74%); T₃₊₄, 6/8 (75%). External irradiation had no significant effect on local control. Prophylactic external irradiation of over 30Gy clearly prevented the development of neck node metastases; 1/11 (9%) compared to 15/37 (41%) for doses under 30Gy. However, there was no significant difference in the 2-year survival rate (82% compared to 92%). Chemotherapy had no significant effect on control of the primary tumor nor on prevention of neck node metastases in T₂ patients. The overall 5-year survival rate was 73%, and by stage: T₁, 79%, T₂, 79%; T₃₊₄, 42%; N_{_}, 76%; N₊, 63%, stage I, 85%; stage II, 79%; stage III+IV 42%. Two cases of osteonecrosis were found in the minimum 2-year follow-up group. We conclude that the combination of ¹³⁷Cs needle implants and external irradiation over 30Gy is excellent treatment protocol for carcinoma of the tongue.

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It is a well-known fact that sublethal heating of cells results in development of transient and non-heritable resistance to subsequent heating. This phenomenon is called thermotolerance. The exact mechanism of its induction or its development is not yet understood. Identifying the inhibitors of thermotolerance induction or thermotolerance development may be helpful in delineating the mechanism of thermotolerance, and the clinical use of hyperthermia. Cepharanthin, a membrane active drug, was tested in the present study. At a concentration of 10μg/ml, this drug caused slight change in the slope of the survival curve (Do) of SCK cells heated one time at 44°C. The presence of this drugd uring heat conditioning (1st heating) or in the interval between the 1st and 2nd heating had little effect on the response of cells to the 2nd heating. On the other hand, the presence of cepharanthin during the 2nd heating significantly reduced the Do of cell survival for the 2nd heating (Do=28.5min). Cepharanthin at a dose of 5μg/ml also enhanced the cell killing effect of the 2nd heating of thermotolerant SCK cells, when it was administeredd uring the 2nd heating (Do=46.8 min). Low extra cellular pH (pHe=6.6) during the 2ndh eating reduced the Do of cell survival of thermotolerant cells (Do=45.8min). Cepharanthin at a dose of 5μg/ml, added during the 2nd heating in low pHe, significantlyenhan ced the cell killing effect of the 2nd heating (Do=29.4min).

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In Intraoperative radiation therapy (TORT) field setup requires great care and accuracy because large single doses are used. We have developed a special TV monitoring system to verify the radiation field in TORT. This system features an assembly consisting of a light source, a film mirror, a TV camera, a 35mm film camera, three monitor TV sets and a videotape recorder. This system was used 41 times during TORT before June 1989. With this system we were able to find three minor accidents during IORT. We conclude that this system provides easier and more accurate setup, and continuous field monitoring.

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