Search results for "Regional Blood Flow"

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…

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…

Relation between autoradiographically measured blood flow and ATP concentrations obtained from imaging bioluminescence in tumors following hypertherm…

1993

The effects of moderate local hyperthermia (43.3 degrees C/30 min) on regional blood flow and regional ATP distribution in the amelanotic hamster melanoma A-Mel-3 were investigated by high-resolution techniques. Blood flow and ATP concentrations were measured simultaneously in treated and untreated tumors and in adjacent tissues by means of (14C)-Iodoantipyrine autoradiography and quantitative imaging bioluminescence in consecutive tissue sections at 3, 12 and 24 hr following treatment. Digital image processing and the use of a special algorithm allowed the regional interrelationship of the 2 parameters to be quantified. Measurements revealed a great heterogeneity of blood flow and ATP betw…

Response of tumour red blood cell flux to hyperthermia and/or hyperglycaemia.

1989

Laser Doppler flowmetry has been applied to subepidermal rat tumours during localized ultrasound hyperthermia and/or moderate, short-term hyperglycaemia. Blood glucose levels were elevated 4-fold by continuous i.v. infusion of D-glucose (4.8 g/kg/60 min). To determine whether the effects of hyperglycaemia on tumour blood flow involved increased rates of glycolysis and lactic acid production, galactose, a sugar not metabolized by the tumour, was administered using the same dose schedule. Hyperglycaemia was accompanied by a 3-fold increase in blood lactate levels and a slight hypervolaemic haemodilution without any significant systematic changes of the arterial blood pressure or respiratory b…

The influence of tumor blood flow and microenvironmental factors on the efficacy of radiation, drugs and localized hyperthermia.

1997

It is generally accepted that tumor blood flow, microcirculation, oxygen and nutrient supply, tissue pH distribution, and the bioenergetic status-factors which are usually closely linked and which define the so-called metabolic microenvironment--can markedly influence the therapeutic response of malignant tumors to conventional irradiation, chemotherapy, other nonsurgical treatment modalities, and the cell proliferation activity within tumors. Currently available information on the parameters defining the metabolic micromilieu in human tumors is presented in this review. According to these data, significant variations in these relevant factors are likely to occur between different locations…

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 …

Insights on the use of thermography in human physiology practical classes

2018

Non invasive blood flow measurement in cerebellum detects minimal hepatic encephalopathy earlier than psychometric tests

2013

AIM: To assess whether non invasive blood flow measurement by arterial spin labeling in several brain regions detects minimal hepatic encephalopathy. METHODS: Blood flow (BF) was analyzed by arterial spin labeling (ASL) in different brain areas of 14 controls, 24 cirrhotic patients without and 16 cirrhotic patients with minimal hepatic encephalopathy (MHE). Images were collected using a 3 Tesla MR scanner (Achieva 3T-TX, Philips, Netherlands). Pulsed ASL was performed. Patients showing MHE were detected using the battery Psychometric Hepatic Encephalopathy Score (PHES) consisting of five tests. Different cognitive and motor functions were also assessed: alterations in selective attention we…

Quantification of fluorescent dyes in organ tissue samples via HPLC analysis

2017

Abstract The determination of regional blood flow via the accumulation of fluorescent microspheres is a concept regularly used in medical research. Typically, the microbeads get extracted from the tissue of interest and are then quantified by measuring the absorption or fluorescence of the incorporated dyes without further separation from the medium. However, in that case the absorption spectra of different dyes can overlap when used simultaneously, leading to an overestimation of the concentration. Additionally, background absorption from the medium can be problematic. Therefore, a high performance liquid chromatography method for the simultaneous detection of four dyes (orange, crimson, y…