Search results for "hyperthermia"
showing 10 items of 95 documents
Effects of tumor necrosis factor-alpha on tumor blood flow and hyperthermic treatment.
1989
The impact of recombinant human tumor necrosis factor-alpha (rhTNF-alpha), given alone or in combination with local hyperthermia, on perfusion and growth of a moderately rhTNF-alpha-sensitive rat tumor (DS-carcinosarcoma) was investigated. DS-carcinosarcomas were implanted into the hind foot dorsum of Sprague-Dawley rats. Tumor blood flow (TBF) was measured with the krypton-85 clearance technique. Treatment with either tumor necrosis factor-alpha (0.1-1.0 mg/kg) or hyperthermia (43.3 and 44.3 degrees C, 40 min) can decrease the perfusion of malignant tumors. The TBF reduction was fully established 2 h after rhTNF-alpha injection and lasted for at least 4 h. The application of local hyperthe…
Pathophysiological and vascular characteristics of tumours and their importance for hyperthermia: Heterogeneity is the key issue
2010
Tumour blood flow before and during clinically relevant mild hyperthermia exhibits pronounced heterogeneity. Flow changes upon heating are not predictable and are both spatially and temporally highly variable. Flow increases may result in improved heat dissipation to the extent that therapeutically relevant tissue temperatures may not be achieved. This holds especially true for tumours or tumour regions in which flow rates are substantially higher than in the surrounding normal tissues. Changes in tumour oxygenation tend to reflect alterations in blood flow upon hyperthermia. An initial improvement in the oxygenation status, followed by a return to baseline levels (or even a drop to below b…
Tumor tissue oxygenation as evaluated by computerized-po2-histography
1990
A computerized pO2 measurement system with a novel electrode motion pattern (Sigma-pO2-histography) was evaluated in vitro and in vivo. The system was found to be reliable in 0.9% saline and 10% hydroxyethylene starch solution and in fresh donor blood. Marked deviations were found in lipid and hemoglobin solutions and in fluorocarbon emulsions. Histograms obtained in rat liver, mouse muscle, and subcutis were similar to previously reported distributions. Direct comparison between Sigma-Eppendorf and self-constructed Whalen-type electrodes in hypoxic tumors gave similar results. A large series of measurements indicated that hypoxic and anoxic tissue areas were frequently found both in isogra…
Hyperlactacidaemia in isolated hyperthermic perfusion of tumour bearing rat limbs: a study of feasibility using a novel infusion solution.
1999
In a methodological study the applicability of hyperlactacidaemia in isolated hyperthermic perfusion of tumour-bearing rat limbs was investigated.In 50 Sprague Dawley rats, DS-sarcoma growth was initiated on the right food dorsum by subcutaneous injection of 0.5 ml ascites cells. In the anaesthetized animals isolated limb perfusion was performed under steady state conditions for 60min using a miniature equipment. Thereafter tumour volume was measured daily. (a) Investigation of feasability: 40 rats were allocated to four groups. Group I: Normothermic perfusion at 38 degrees C, n = 10; Group II: Hyperthermic perfusion at 40-41 degrees C, n = 10; Group III: Normothermic perfusion at 38 degree…
Circulatory and metabolic responses of malignant tumors during localized hyperthermia
1980
The effect of localized hyperthermia on the circulatory responses and on the oxygen and glucose supply has been evaluated in tissue-isolated rat tumors utilizing an in situ perfusion system. On the average, localized hyperthermia caused a significant increase in total tumor blood flow after raising of the mean tumor temperature from 37 degrees C to 39.5 degrees C. At higher temperatures (42 degrees C) total tumor blood flow decreased to a level somewhat below the flow during normothermia. However, there were great interindividual differences in the response of blood flow to temperature. The changes in blood flow were paralleled by variations of the O2-consumption and of the glucose uptake o…
In vivo targets of recombinant human tumour necrosis factor-α: blood flow, oxygen consumption and growth of isotransplanted rat tumours
1989
The impact of recombinant human tumour necrosis factor-alpha (1 microgram kg-1 to 1 mg kg-1; 6.6 x 10(6) U mg protein-1) on blood flow, oxygen consumption and growth of a moderately TNF-sensitive rat tumour (DS-carcinosarcoma) was studied. Tumour growth was stimulated at low TNF doses (1 and 10 micrograms kg-1) and significantly retarded at higher TNF dose levels (0.1 and 1 mg kg-1). Growth changes were concomitant with variations in oxygen consumption, lactate release and acidification of the metabolic micromilieu. Both single and repeated application of low TNF doses (1-10 micrograms kg-1 i.v.) increased tumour perfusion whereas single administration of high TNF dose levels (0.1-1 mg kg-1…
Experimental evidence for a hyperthermia-induced breakdown of tumor blood flow during normoglycemia
1983
A compilation of experimental data is presented indicating that hyperthermia alone can achieve a significant inhibition of tumor blood flow if appropriate heat exposure times and tissue hyperthermia levels are chosen.
Tumour-growth inhibition by induced hyperglycaemia/hyperlactacidaemia and localized hyperthermia.
1996
The present study was undertaken to exploit pathophysiological properties of solid tumours for a tumour-specific therapy. Experiments were carried out on DS-sarcomas implanted s.c. in the hind foot dorsum of Sprague Dawley rats. Treatment strategies included tumour acidification, lactate accumulation and disturbance of the microcirculation by induced systemic hyperglycaemia/hyperlact-acidaemia (15-25/10 mmol/L; for 60 min) as well as localized hyperthermia (water-bath; 43 degrees C, 30 min.). A special infusion solution was developed for the systemic treatment containing glucose, lactic acid and organic buffer without inorganic ions. Growth kinetics of tumour volume and animal survival were…
MR Thermometry Data Correlate with Pathological Response for Soft Tissue Sarcoma of the Lower Extremity in a Single Center Analysis of Prospectively …
2020
Background: There is a strong biologic rationale for using locoregional hyperthermia in soft tissue sarcoma and a randomized trial reported significant improvements with hyperthermia. The aim of this study was to describe the opportunities of magnetic resonance (MR)-based thermometry in a cohort of soft tissue sarcoma patients undergoing combined radiotherapy and locoregional hyperthermia. Patients and Methods: For eleven evaluable patients, tumor volume (VTu) and a separate volume for temperature analysis with reliable temperature distribution (Vtherm) were contoured for every hyperthermia treatment (103 therapies). Temperature data were recorded for all tumors and were correlated with cli…
Tetrachlorodecaoxide Improves the Oxygenation Status of Multicellular Tumor Spheroids
1986
Insufficient O2 supply to solid tumors has been recognized since many years to be a crucial problem in cancer therapy. Hypoxia and anoxia may increase the resistance of tumor cells to certain antiproliferative drugs or to ionizing radiation. Numerous approaches to overcoming this problem have been reported in the literature. Efforts have been made in mainly two basic directions: (1) the development of therapeutic means which are particularly efficient in hypoxic and nutrient-deprived tissue areas or which are at least independent of the tissue oxygenation, and (2) the development of methods for improving the oxygenation status of solid tumors. Among the former approaches, the cytotoxicity o…