Search results for "hyperthermia"
showing 10 items of 95 documents
TISSUE OXYGENATION AND NORMAL AND HYPERTHERMIC CONDITIONS
1981
Publisher Summary This chapter describes the tissue oxygenation and normal and hyperthermic conditions. The knowledge of the effect of hyperthermia on tumor and normal tissue blood flow is important not only for the effect of hyperthermia on hypoxic cells at the time of radiation, but also for differential tumor heating. There is considerable evidence from plethsmography that an elevation of normal tissue temperature to 41°C is accompanied by a considerable increase in blood flow. The chapter discusses studies that were conducted to examine changes in the microenvironment of normal and tumor tissue as measured directly with ultramicroelectrodes. In situ studies were carried out in fourth ge…
Pathophysiological aspects of hyperthermia
1992
Blood flow in many rapidly growing tumors is sluggish leading to an impairment of convective heat dissipation which facilitates tumor heating compared to normal tissues. In addition, the compromised microcirculation causes a hostile metabolic micromilieu which can modulate the therapeutic effect of heat. After clinically relevant heat doses, a shut-down of tumor microcirculation is often observed creating a “heat-reservoir” and aggravating tumor hypoxia, acidosis, and substrate and energy depletion, factors which are known to greatly enhance tumor cell killing by heat. Since the mechanisms described are mostly derived from experimental results on fast-growing animal tumors, the clinical rel…
Impact of Localized Microwave Hyperthermia on the Oxygenation Status of Malignant Tumors
1982
Considerable insight into the mechanisms of heat induced cell death in vitro has been gained during recent years (for reviews see 1–3). Besides the direct cell killing effect of heat, many microenvironmental or milieu factors seem to play an important role during heat treatment of solid tumors in vivo, such that a preferential effect of hyperthermia on tumors has been postulated for the in situ conditions. Environmental factors affecting the tumor milieu, such as tissue oxygen partial pressures, pH values, glucose (?) and lactate levels, nutrient supply and drainage of wastes, have thus become a subject of topical interest.
Rapid inactivation and proteasome-mediated degradation of OGG1 contribute to the synergistic effect of hyperthermia on genotoxic treatments
2013
Inhibition of DNA repair has been proposed as a mechanism underlying heat-induced sensitization of tumour cells to some anticancer treatments. Base excision repair (BER) constitutes the main pathway for the repair of DNA lesions induced by oxidizing or alkylating agents. Here, we report that mild hyperthermia, without toxic consequences per se, affects cellular DNA glycosylase activities, thus impairing BER. Exposure of cells to mild hyperthermia leads to a rapid and selective inactivation of OGG1 (8-oxoguanine DNA glycosylase) associated with the relocalisation of the protein into a detergent-resistant cellular fraction. Following its inactivation, OGG1 is ubiquitinated and directed to pro…
Electromagnetic Hyperthermia — Foundations and Computer Modelling
2006
The usage of heating power as a healing system has been well-known for long time. A completely new motivation, however, came up when heat treating was recognized as a new and promising form of cancer therapy. It was found that cancer growth was stopped at temperature higher than about 42 C. It created new subject of research in the area of application of electromagnetic fields in medicine. In the paper the two main methods of heating have been described and two kinds of devices have been presented. Some advantages and drawbacks of the methods are discussed.
Experimental Hyperthermia during Cardiac Arrest and CPR Is Associated with Severe Spontaneous Hypothermia in Mice
2012
Background: Since genetically engineered mice are becoming more and more available, these animals become of high interest to study physiologic and pathophysiologic pathways of brain ischemia. The aim of this study was to examine body temperature (Tb), physical activity variation and neurohistopathology in mice exposed to normothermic and hyperthermic cardiac arrest and cardiopulmonary resuscitation (CA/CPR). Methods: Male C57Bl/6 mice weighing 22 - 27 g were implanted intraperitoneally with a radio telemeter and subjected to 10 min cardiac arrest followed by cardiopulmonary resuscitation. Normothermia (37.5°C) or hyperthermia (39.0°C) was induced by controlling pericranial temperature durin…
Tumour Blood Flow Following Local Ultrasound Heating Computed from Thermal Clearance Curves
1987
Thermal clearance curves following termination of ultrasound-induced hyperthermia in human mammary carcinomas implanted into the flanks of nude rats were studied. They were found to be monoexponential in form, both with and without blood flow. From the difference between the inverse time constants with and without flow, the tumour blood flow rate could be calculated. Blood flow was found to increase with very short exposure times at the therapeutic hyperthermia temperature and subsequently decrease as the exposure time increased. A higher therapeutic hyperthermia temperature augmented this effect.
Pathophysiology of Tumors in Hyperthermia
1988
The response of tumor cells to hyperthermia is critically influenced by a number of pathophysiological factors both in vitro and in vivo. The most relevant factors in this context are tumor blood flow, tissue oxygenation, the energy status, and the pH distribution, which in turn define the cellular microenvironment.
Microwave-Induced Hyperthermia and Cytostatic Agent for Superficial Bladder Cancer
2005
The efficacy and local toxicity of the intravesical combination of microwave-induced hyperthermia with a cytostatic agent in patients affected by superficial bladder cancer is presented. Between 1994 and 2002, two studies were performed on ablative and adjuvant intravesical thermo-chemotherapy. The ablative study demonstrated complete tumor eradication in 88% of patients who should have undergone cystectomy due to diffuse multiple papillary tumors non-responsive TUR and intravescical adjuvant therapy. In a randomized study, comparing adjuvant thermo-chemotherapy vs. standard chemotherapy with mitomycin C, recurrence-free survival analysis at 24 months revealed a significant difference in f…
Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance.
2020
Journal of nanobiotechnology 18, 22 (2020). doi:10.1186/s12951-020-0580-1