Search results for " blood flow"

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…

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.

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 …

Pathophysiology of traumatic brain injury.

2007

The knowledge of the pathophysiology after traumatic head injury is necessary for adequate and patient-oriented treatment. As the primary insult, which represents the direct mechanical damage, cannot be therapeutically influenced, target of the treatment is the limitation of the secondary damage (delayed non-mechanical damage). It is influenced by changes in cerebral blood flow (hypo- and hyperperfusion), impairment of cerebrovascular autoregulation, cerebral metabolic dysfunction and inadequate cerebral oxygenation. Furthermore, excitotoxic cell damage and inflammation may lead to apoptotic and necrotic cell death. Understanding the multidimensional cascade of secondary brain injury offers…

Insights on the use of thermography in human physiology practical classes

2018

Prevention and treatment of intracranial hypertension

2007

Intracranial pressure (ICP) is the pressure exerted by cranial contents on the dural envelope. It comprises the partial pressures of brain, blood and cerebrospinal fluid (CSF). Normal intracranial pressure is somewhere below 10 mmHg; it may increase as a result of traumatic brain injury, stroke, neoplasm, Reye's syndrome, hepatic coma, or other pathologies. When ICP increases above 20 mmHg it may damage neurons and jeopardize cerebral perfusion. If such a condition persists, treatment is indicated. Control of ICP requires measurement, which can only be performed invasively. Standard techniques include direct ventricular manometry or measurement in the parenchyma with electronic or fiberopti…

Glomerular Filtration Rate in Renal Damage

2015

Renal function is mainly represented by the glomerular filtration (GF), which is dependent on the number and function of the nephrons. Glomerular filtration declines progressively after the third decade with a progressive loss of 1 % per year. In addition to diseases producing direct damage in the glomerular structures, high blood pressure values, diabetes, and dyslipidemia are the main factors increasing the rate of GF decline over the years. Other functional parameters of the kidney such as renal plasma flow or tubular functions are not measured in daily practice in hypertension and are not related to risk for cardiovascular disease (CVD).

High-intensity transient signals during laparoscopic surgery in children.

2009

Background Laparoscopic interventions in children gain increasing popularity. Pneumoperitoneum as applied during laparoscopic surgery can induce gas emboli formation, but it is unclear whether this is associated with cerebral embolic events. To investigate the hypothesis that pneumoperitoneum causes cerebral emboli in children, the number and intensity of high-intensity transient signals (HITS) detected using transcranial Doppler ultrasonography were assessed before and after induction of pneumoperitoneum. Methods Twenty children were monitored during laparoscopic surgery. General anaesthesia was performed using sevoflurane and sufentanil or alfentanil. Pressure-controlled ventilation was a…

Implementation of laser speckle contrast analysis as connection kit for mobile phone for assessment of skin blood flow

2014

Laser speckle contrast analysis (LASCA) offers a non-contact, full-field, and real-time mapping of capillary blood flow and can be considered as an alternative method to Laser Doppler perfusion imaging. LASCA technique has been implemented in several commercial instruments. However, these systems are still too expensive and bulky to be widely available. Several optical techniques have found new implementations as connection kits for mobile phones thus offering low cost screening devices. In this work we demonstrate simple implementation of LASCA imaging technique as connection kit for mobile phone for primary low-cost assessment of skin blood flow. Stabilized 650 nm and 532 nm laser diode m…