Search PubMed⌕ Search

Biomedical subjects

S Jo

Publications and source records attributed to S Jo.

53 records · Page 3Linked to original sources
PubMed1986

Effects of step-up and step-down heating on a transplantable murine tumor.

The effects of step-up (42----44 degrees sequence) and step-down (44----42 degrees sequence) heating were studied on a transplantable mammary adenocarcinoma of C3H/He mouse. Tumor-bearing legs were immersed in a water bath and the response to hyperthermia was evaluated in terms of the delay in tumor growth. Tumor growth was delayed greatly with increase in the duration of treatment with 44 degrees hyperthermia, whereas with 42 degrees hyperthermia of up to 180 min, tumor growth was delayed only slightly. The effects of step-up heating were similar to those of 44 degrees hyperthermia alone and the response was enhanced by a factor of 0.9-1.1 with the 60-min treatment at 42 degrees followed by treatment at 44 degrees. Thermal resistance developed when the preheating time at 42 degrees was longer than 30 min. On the other hand, the tumor response was markedly enhanced by step-down heating by a factor of 1.8-2.4 with the treatment at 44 degrees followed by 60-min treatment at 42 degrees. Since the enhancement factor for skin damage found previously was similar to that for the tumor, therapeutic gain cannot be expected by the use of these combined heat treatments.

Animals↗
PubMed1986

[Clinical evaluation of thermoradiotherapy for deep-seated tumors].

Between October 1981 and February 1985, RF capacitive heating with frequencies of 8 and 13.56 MHz was combined with radiotherapy in the treatment of 28 deep-seated tumors that were previously considered incurable by conventional radiotherapy alone. Intra-tumor temperatures of higher than 42 degrees C were achieved in 69% of overall heat sessions. Clinical evaluation was made by calculating the percentage of tumor regression from pre- and post-treatment CT films. As for the criteria of clinical evaluation, complete regression (CR) was defined as clinical disappearance of any measurable tumor, partial regression a and b (PRa and PRb) as regressions of 80% or more and 50 to less than 80%, respectively, and no response (NR) as less than 50% regression. Of 28 deep-seated tumors, 4 (14%) achieved CR, 5 (18%) PRa, 11 (39%) PRb and 8 (29%) NR. In some NR and PRb tumors, however, CT scan revealed remarkable increases in low density areas that suggested necrosis of tumor tissues. This was proved by subsequent histological examination. Clinical tumor response appeared to decrease as the initial size of the tumor increased and to be independent of any TDF factor for radiotherapy and the number of heat sessions.

Combined Modality Therapy↗
PubMed1986

[Clinical results of radiofrequency capacitive hyperthermia in deep-seated tumors].

The advantages of deep radiofrequency (RF) capacitive heating are its applicability to various anatomical sites and negligible systemic effects. The disadvantages are on the other hand, that its primary usefulness is limited to patients with thin subcutaneous fat and with large or hypovascular tumors. Clinical benefits of RF hyperthermia combined with radiotherapy are strongly suggested for deep-seated tumors. Intratumor low density areas on post-treatment CT and histopathological examinations are considered important parameters to assess the tumor response to thermoradiotherapy.

Abdominal Neoplasms↗
PubMed1984

Clinical results of radiofrequency hyperthermia combined with radiation in the treatment of radioresistant cancers.

Clinical results of radiothermotherapy applied to 40 radioresistant tumors in 36 patients were reported. Hyperthermia was administered locally using two radiofrequency (RF) capacitive heating equipment systems developed in our institution under the collaboration of Yamamoto Vinyter Co. Ltd. Hyperthermia was given twice weekly immediately after irradiation. Intratumor temperatures of 41 degrees C to 44 degrees C were maintained for 30 to 60 minutes. Radiation doses varied from 32 Gy to 60 Gy. Of the 40 tumors treated, 21 (53%) showed complete response, 16 (40%) partial response, and 3 (7%) no response when the tumor response was assessed by tumor size measurement. Of eight patients who had matched tumors treated with either radiation alone or radiation plus hyperthermia, six patients showed better response in tumors treated with radiothermotherapy than in tumors treated with radiation alone. Skin reactions following radiothermotherapy and radiation alone were comparable. The tumor response was greatly dependent on the tumor size. Greater response was observed in small tumors, although histologic examinations and long-term follow-up studies revealed an excellent effect of radiothermotherapy on the large tumors as well as on the small tumors. Tumor responses correlated with tumor center temperatures but not with histologic features. Our clinical results indicate that RF hyperthermia combined with radiation has a therapeutic benefit in the treatment of radioresistant cancers.

Body Temperature↗
PubMed1983

[Biological and physical approach to the improvement of radiotherapy].

A double blind trial of misonidazole (MISO) was undertaken. A total of 147 patients were enrolled. They were randomly allocated into two groups receiving either MISO or placebo. They were irradiated with 2 Gy 5 times a week to a total dose of about 60 Gy. 0.5g/m2 of MISO was given orally 4 hours before each irradiation. The effect of the treatment was evaluated as a decrease in the volume of the tumors. No radiosensitizing effect of the drug was observed. Twenty-nine tumors considered to be radioresistant were treated by RF hyperthermia combined with radiation. 48% of the tumors developed complete regression. No definite relationship between heat sensitivity of the tumors and their histological types was observed.

Animals↗
PubMedDate not supplied

Clinical results of thermoradiotherapy for locally advanced and/or recurrent breast cancer--comparison of results with radiotherapy alone.

From August 1979 until 1988, 26 breast cancer patients with 30 tumours were treated by hyperthermia in combination with radiotherapy. Of the 30 tumours, 11 were locally advanced primary tumours (group 1), six were locally advanced recurrent tumours after operation (group 2) and 13 were locally recurrent tumours after radiotherapy (group 3). The thermal profiles showed that the capability of an RF capacitive heating device is comparatively high for large breast tumours with a volume of more than 100 cm3, and that of a 430 MHz microwave device with a single-lens applicator is excellent for localized tumours. The response rate of group 1 and 2 tumours was excellent, and superior to that of historically controlled tumours that were treated by radiotherapy alone from July 1962 until August 1979. In group 3 the tumour response to thermoradiotherapy was not different from that to radiotherapy, but the possibility of significantly reducing total irradiation dose was indicated. More than one good heating session led to a significantly high local response, and factors having a tendency to influence local response were average minimum tumour temperature, tumour volume, and number of effective heat treatments.

Adult↗
PubMedDate not supplied

Phase I/II trial of preoperative thermoradiotherapy in the treatment of urinary bladder cancer.

Between April 1984 and September 1988, preoperative radiotherapy or thermoradiotherapy was administered to 49 patients with bladder cancer (T1-4N0M0; UICC classification, 1987). Twenty-one patients were preoperatively treated by radiotherapy alone, with 4 Gy per fraction and three fractions per week to a total dose of 24 Gy (TDF = 53, group 1). The other 28 patients were treated by the same radiotherapy regimen in combination with hyperthermia (group 2). Regional hyperthermia was administered for 35-60 min immediately after irradiation (two sessions per week to a total of four sessions) using an 8 MHz RF capacitive heating device. Group 2 was divided into group 2 (high), in which the average intravesical temperature (T(av)) was > 41.5 degrees C, which was the mean value, and group 2 (low) with a T(av) < 41 x 5 degrees C. Group 2 (high) showed a significantly higher incidence of down-staging and tumour degeneration than both group 1 and group 2 (low). In addition, the local recurrence rate was lower and survival time was longer in group 2 than in group 1, although not significantly so. In particular, the patients with T3-4 or grade 3 bladder cancer in group 2 had a longer average survival than those in group 1, although the difference was not significant. The toxicity associated with hyperthermia was pain during treatment, and complications were not serious.

Adult↗
PubMedDate not supplied

Response of mammary tumors of C3H/He mice to hyperthermia and bleomycin in vivo.

The cytotoxicity of bleomycin in vitro has previously been shown to be enhanced by hyperthermia. This study demonstrates in vivo a synergistic interaction between local hyperthermia (43 degrees C, 45 min) and bleomycin (15 mg/kg) against implanted mammary tumors of C3H/He mice. Hyperthermia was given by water bath heating. When combined treatments of heat and bleomycin were administered within 30 min of each other, a synergistic effect was observed. In contrast, when the interval between heat and bleomycin injection was longer than 30 min, only an additive effect was obtained. Timing is therefore considered to be a critical factor for the optimal combination of hyperthermia and bleomycin.

Animals↗