Search results for "Perth"
showing 10 items of 156 documents
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…
Effect of Localized Hyperthermia on Tumor Blood Flow and Oxygenation
1984
Hyperthermia has been shown to have a lethal effect in tumor cell cultures, particularly at temperatures above 42°C.1 Moreover, it has been demonstrated that hyperthermia retards the growth rate of certain types of malignant tumors and can be effective in completely eradicating some tumors without any major damage to normal tissue.2,3,4 The differential response of solid tumors in vivo to heat treatment in comparison to normal tissue probably results from several factors. Among these the in vivo micro-environment seems to play a decisive role. In general, the interstitial milieu of solid tumors is characterized by tissue hypoxia and anoxia5,6 and by severe tissue acidosis.7 These unfavorabl…
The Vascularization of Experimental and Human Primary Tumors: Comparative Morphometric and Morphologic Studies
1998
The importance of the blood vessel system in solid tumors has given rise to an increasing interest in this system as a direct target for tumor therapy, i.e. vascular targeting (Denekamp, 1984). Furthermore, its importance as a route for delivery of anticancer drugs (chemo- and immunotherapies) or photosensitizers (photodynamic laser therapy), as well as its modulatory influences on radiotherapy and hyperthermia — the former greatly depending on the amount of oxygen available, the latter on heat transfer — are evident. Numerous studies on the energy metabolism of solid tumors (Vaupel et al., 1987, 1989) have pointed out the functional importance of the blood vessel system and stress the need…
Blood Flow and Oxygen Supply to Human Mammary Carcinomas Transplanted into Nude Rats
1985
Tumor blood flow (TBF), by itself, greatly influences the efficiency of nonsurgical therapeutic modalities, especially chemotherapy and hyperthermia. Furthermore, TBF is one of the most important determinants of tumor tissue oxygenation in vivo, thus playing a relevant role in tumor growth kinetics and in the development of regressive changes. In addition, the oxygenation of tumor tissue strongly determines the efficiency of radiation therapy and to a certain extent, pharmacodynamics of some antiproliferative drugs. Despite the considerable information available for rodent tumor systems, there are only sporadic ireports on blood flow (Beaney et al., 1984, Johnson, 1976, Mantyla, 1979, Manty…
Concurrent Measurements of O2 Partial Pressures and pH Values in Human Mammary Carcinoma Xenotransplants
1986
Due to severe restrictions of convective and diffusive transport, hypoxic or even anoxic areas exist in malignant tumors. In addition, a high glycolytic rate in tumors both in the presence and absence of oxygen and the insufficient removal of the hereby produced lactic acid lead to an acidification of the tumor tissue. Both hypoxia and acidosis can influence the efficacy of irradiation, chemotherapy and hyperthermia. However, no comprehensive data on the development of both hypoxia and acidosis within the same tumor are available to date. In particular, there is no information regarding human tumors. Therefore, a new model has been developed which allows the systematic evaluation of both pa…
Vascular Meets of Localized Hyperthermia
2008
When hyperthermia is applied in vitro, no fundamental differences can be seen between the response to normal and tumor cells. In vivo however, selective damage of tumor cells can be achieved and this phenomenon can be largely attributed to a number of characteristic properties of the blood vessels within solid tumors. Changes in blood flow induced by hyperthermia can influence the response of a tumor to heat either by affecting the delivery of heat through changes in heat dissipation or by a modulation of the tumor microenvironment which may in turn affect the thermosensitivity of tumor cells. Studies in experimental and human tumors suggest however that an accurate prediction of changes in…