Search results for "Perth"
showing 10 items of 156 documents
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
Microcirculatory and pH Alterations in Isotransplanted Rat and Xenotransplanted Human Tumors Associated with Hyperthermia
1988
The rationale for considering the use of hyperthermia as an antitumor agent is based on three different mechanisms of action depending on the hyperthermia levels chosen: At moderate hyperthermia levels (40°–42.5° C) heat can increase the radiosensitivity and/or the chemosensitivity. At higher tissue temperatures ( > 42.5° C) hyperthermia acts as a cytotoxic agent since mammalian cells die after heating in a temperature-, time-, and cell cycle-dependent manner. Besides direct effects on the cell membranes, on the cytoskeleton, on metabolic processes, on DNA replication, and on RNA and protein synthesis, indirect effects distinctly modulating the anticancer action of heat have to be considere…
Effects of the exercise in the cerebral blood flow and metabolism: A review
2015
In recent years it has been shown that cerebral blood flow is affected by intense exercise, what may even lead to a reduction in the cognitive capacity. This statement is contrary to the traditional belief that cerebral blood flood remains constant and unaltered even when exercise is performed. During physical exercise of moderate intensity, cerebral blood flow increases in the cerebral areas responsible for movement. Moreover, recent studies have observed that cerebral blood flow decreases during high-intensity exercise as a consequence of a local hyperventilation and vasoconstriction of the areas with lower cerebral activity. Traditionally, the glucose has been considered as the main and …
Effect of hyperthermia on tumor blood flow.
1984
Differences in blood perfusion rates between tumors and normal tissue can be utilized to selectively heat many solid tumors. Blood flow in normal tissues is considerably increased at temperatures commonly applied during localized hyperthermia. In contrast, tumor blood flow may respond to localized heat typically in two different blood flow patterns: Flow may either decrease continuously with increasing exposure time and/or temperature or flow may exhibit a transient increase followed by a decline. A decrease in blood flow at high thermal doses can be observed in most of the tumors, whereas an increase in flow at low thermal doses seems to occur less frequently. The inhibition of blood flow …
Die intraoperative Hyperpyrexie bei Osteogenesis imperfecta-Betroffenen
2000
The aim of this study was to evaluate the influence of different types of anesthesia upon the intra- and postoperative body temperature in osteogenesis imperfecta patients. The development of an intraoperative hyperpyrexia of unknown origin is a typical phenomenon in patients with osteogenesis imperfecta. Body temperatures of up to 40 degrees C are known to complicate the operation. Therefore, in a retrospective study, the pre-, intra- and postoperative body temperature curves of 45 operations under different anaesthesias were measured. Group A underwent a common balanced anaesthesia with the volatile anaesthetic Enfluran in combination with Fentanyl, while group B was operated on under tot…
Analyzing the electrophysiological effects of local epicardial temperature in experimental studies with isolated hearts
2008
As a result of their modulating effects upon myocardial electrophysiology, both hypo- and hyperthermia can be used to study the mechanisms that generate or sustain cardiac arrhythmias. The present study describes an original electrode developed with thick-film technology and capable of controlling regional temperature variations in the epicardium while simultaneously registering its electrical activity. In this way, it is possible to measure electrophysiological parameters of the heart at different temperatures. The results obtained with this device in a study with isolated and perfused rabbit hearts are reported. An exploration has been made of the effects of local temperature changes upon…