Biomedical subjects
Publications and source records attributed to V F Lopatin.
An analysis of the data on the treatment of 91 cases of advanced cancer of the larynx showed that local UHF-hyperthermotherapy is more efficient than the SHF one as a component of radiotherapy. Use of the latter procedure was followed by a higher rate of late-onset radiation injuries. Moreover, combined application of hyper-fractionated irradiation and UHF-hyperthermotherapy involved practically no grave complications while 5-year survival increased.
The purpose of the study was to evaluate the effectiveness of RF-hyperthermia and regional intraarterial hyperglycemia as adjuvant radiotherapy vs conventional radiotherapy of advanced head and neck cancers. Altogether 115 patients with advanced T3-T-4 carcinoma of the tongue, oral cavity and oropharynx underwent external radiotherapy (Co-60). An RF capacitative heating device operating at 40.68 MHz was employed twice a week, a total of 4 sessions per patient. Intratumor temperature was 41.5-43 degrees C. Hyperglycemia was performed via the branches of the carotid artery, a total of 3 sessions per patient. There were 4 groups (1-31 patients on conventional radiotherapy; 2-24 patients on thermoradiotherapy; 3-30 patients on radiotherapy plus regional hyperglycemia; 4-30 patients underwent combined radio-modification). A complete response was 29% for conventional radiotherapy, 67% for thermoradiotherapy, 60% for radiotherapy plus hyperglycemia, and 77% for combined radio-modification. A 2-year local control was found to be 13% for radiotherapy, 37% for thermoradiotherapy, 17% for radiotherapy plus hyperglycemia, and 35% for combined radio-modification. Only hyperthermia was found to improve a 2-year local control of advanced oropharyngeal cancer.
The paper is devoted to comparative estimation of radiation and combined therapy of laryngeal cancer patients using combined radiomodification including local hyperthermia, total hyperthermia, chemotherapy and a method of dynamic dose fractionation. Complete and significant tumor regression at a dose of 32 Gy was noted in the study group (77 patients) and in the control group (64%). Radiotherapy against a background of combined radiomodification tends to increase the 3-year survival up to 86% as compared to 66.7% in the control group.
Potentiation of the effect of radiation and combined treatment of laryngeal cancer by local hyperthermia was studied in 43 patients. In 51 cases of the control group (radiotherapy), conventionally-dynamic fractionation of dose was used. At 32 Gy, complete or partial regression of tumor was observed in 72.1% in the study group and 64.7% of controls. An increased frequency of radiation-induced damage of the oral mucosa was observed whereas radiation epidermitis did not occur. Three-year relapse-free survival following a course of radical thermoradiotherapy was as high as 76.5% compared to 40% in controls. Overall three-year survival (including the results of combined treatment and treatment for relapse) increased from 66.7 to 83.3%.
The extent of metastatic spread and the life span depend on the level of nonspecific resistance of the body of patients with osteogenic sarcoma. Chemoradiation therapy reduces antitumoral resistance of patients, and the use of local UHF hyperthermia prevents this negative effect of complex treatment.
The authors described methods developed by them for measuring heat production in autopsy sections by taking pulse thermograms during local capacitative healing of tissues using special electrode devices filled in with liquid dielectric. Thermograms of heat production distribution on limb sections were shown. Qualitative peculiarities of heat production distribution determined by tissue topological structure, were analysed.
The paper is concerned with the results of a study of the relation of a metastatic spreading of mouse Lewis carcinoma to temperature distribution in the area of a tumor and healthy tissue damage. It was shown that a significant metastatic spreading inhibition was observed in selective MWF-hyperthermia (43-46 degrees C, 30 min). In the absence of a selective hyperthermal exposure when both tumors and healthy tissues were damaged (at the same thermal dose), there was a tendency to metastatic spreading enhancement. A considerable metastatic growth was noted after tumor-affected limb amputation without hyperthermal exposure.
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The differential heating (35-43.5 degrees C, 30 min) of sarcoma 45 causes an increase of its growth due to the growth of the tumour regions uneffected by the damaging temperature and having the temperature comparable to the normal temperature of experimental animal. The differential heating just after gamma-irradiation decreases the damaging effect of ionizing radiation on tumour tissue, or to be more precise, on the tumour regions with subhypothermal temperature. Possible bioenergetic mechanisms of the trophic and radioprotective effects at differential heating of tumours by the electric UHF-field are discussed.
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Studies performed on rats of line Wag with R-1 tumor, transplanted into the femoral region, indicated that it is possible to use a UHF field for hyperthermia therapy of malignant tumors without inflicting an injury to the normal adjacent tissues and overheating of the organism as a whole. There was found a thermal threshold being in the temperature range of 42--43 degrees, above which a more rapid tumor cell death was noted; it is most radioresistant tumor cells which are first overheated and destructed.
Studies performed on mice transplanted sarcoma 180 subcutaneously indicated that the UHF-field of non-thermogenic intensity in multiple (5-10 fold) total irradiation inhibits the tumor growth (T = 60%) and produces a 1.5 times increase of an average survival in tumor-bearing animals. It is suggested that there is a direct relationship between the increased antiblastic function of the body and a stimulating effect of the UHF-field on the immune response in animals.
It was found that combined treatment of sarcoma 180 with local U. H. F.-hyperthermia and carminomycin resulted in the tumor growth inhibition by more than 90 per cent, which was much higher than the effect of every agent alone. The thermochemotherapy allowed a decrease in the dose of the antibiotic without decreasing the antitumor effect. The U. H. F.-hyperthermia has an independent tumorolytic effect and promotes selective accumulation of carminomycin by the tumor.
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The experiments on male mice of SVA line showed that irradiation in the UHF-field 48 hours after the animal immunization with sheep erythrocytes increased the number of the antibody-producing cells in the spleen at least 3 times. On the background of immunodepression induced by rubomycin the UHF-field increased the primary immune response 2.5 times and the number of cariocytes in the spleen 1.8 times as compared to the control.