Search results for "Cerebral blood flow."

Characterization of the cortical laser-doppler flow and hippocampal degenerative patterns after global cerebral ischaemia in the goat.

1998

Large-animal models offer several advantages in the study of cerebral ischaemia: easier control of physiological variables, easier neuropathological evaluation, etc. In the present study we have taken advantage of the unique cerebrovascular anatomy of the goat to reproduce a model of reversible, incomplete, global cerebral ischaemia in a large-sized animal species, in which the effects of successive manoeuvres to stop and re-start cerebral blood flow can be recorded continuously. Early cortical laser-Doppler flow response (up to 2 h) and delayed neuronal degeneration (7 days) in the hippocampal CA1 subfield have been analysed in goats undergoing 5, 10 or 20 min of transient, global cerebral…

Regional Cerebral Blood Flow in Cases of Brain Tumor

1969

The present series consists of 21 patients with brain tumors: 12 malignant gliomas, 4 oligo- dendro gliomas, 3 meningeomas and 2 metastases, studied by the133Xe-gamma-clearance rCBF method. In 16 patients at least 3 determinations of rCBF were performed: a) in the resting state, R; b) during hyperventilation, HV, and c) during hypertension, HT. Of the remaining 5 patients, 1 was studied only during R, while the other 4 were submitted either to HV or to HT additionally to the R study. The average age of this series of patients was 47 years, the youngest being 19 and the oldest 64. rCBF studies had to be performed under general anesthesia (N2O + O2, Engstrom respirator) in 5 instances in whic…

Description of the response of a new multi-parametric brain sensor to physiological and pathophysiological challenges in the cortex of juvenile pigs

2014

AIM Monitoring of intracranial pressure (ICP), local cerebral blood flow (CBF) and oxygen is part of modern intensive critical care medicine. Preclinical evaluation of newly developed catheters that should monitor several parameters simultaneously is reported poorly in the literature. The goal of our study was (1) to evaluate a new multi-parametric sensor in brain tissue and (2) to establish a testing protocol using pathophysiological challenges that target measured parameters of the sensor and autoregulatory boundaries and could be used as preclinical standard protocol in future studies. MATERIAL AND METHODS We describe data from 12 new multi-parametric brain sensors (MPBS) that were impla…

Effect of Hyper- and Hypoventilation on CBF during Anesthesia

1969

Alexander and Wollman [1, 2, 4, 8], Harper [5] and McDowall and other investigators have published observations on CBF during anaesthesia in man and dog, when arterial pCO2 was altered by hyper- or hypoventilation.

Microcirculation after cerebral venous occlusions as assessed by laser Doppler scanning.

1997

✓ Research on cerebral venous circulation disturbances (CVCDs) has been limited partly by the paucity of animal models that produce consistent venous infarction. Occlusion of two adjacent cortical veins in rats by means of a photochemical thrombotic technique provides a minimally invasive, clinically relevant, and reproducible model suited to study the pathophysiology of CVCDs. In this study, the effects of venous occlusion on regional cortical blood flow and the brain damage that ensues were evaluated. Cortical vein occlusion was induced by photoactivation of rose bengal via 100-µm fiberoptic illumination. The cerebral venous flow pattern was examined using fluorescence angiography until 9…

Alterations of regional cerebral blood flow and oxygen saturation in a rat sinus-vein thrombosis model.

1996

Background and Purpose The pathophysiology of sinus-vein thrombosis (SVT) in patients and experimental animals is still poorly understood. This study was designed to examine and further elucidate the pathophysiological sequence of events, especially the relationship between local and regional blood flow and hemoglobin oxygen saturation (HbSO 2 ) detected at identical locations. The use of both parameters as outcome indicators should be compared. Methods SVT was induced by ligation of the superior sagittal sinus (SSS) and slow injection of kaolin-cephalin suspension into the SSS in rats. Regional cerebral blood flow (rCBF) was assessed by laser-Doppler flowmetry together with regional HbSO …

Reinterpreting the Magnetic Resonance Signs of Hemodynamic Impairment in the Brains of Multiple Sclerosis Patients From the Perspective of a Recent D…

2010

Multiple sclerosis patients examined with perfusion magnetic resonance (MR) imaging techniques have been found to have patterns of abnormal blood flow. These include prolonged mean transit time, a trend toward decreased cerebral blood flow in the area of plaques, and decreased cerebral blood flow and prolonged mean transit time within normal-appearing white matter. In-creased cerebral blood flow and volume and decreased mean transit time (compared with the baseline values before the relapse) were found to precede the development of plaques. In addition, susceptibility-weighted imaging utilizing deoxyhemoglobin as the contrast has revealed that venous blood in cerebral veins of multiple scle…

Cerebral blood flow and cerebral death

1969

At present the diagnosis of cerebral death is based on the absence of manifestations of cerebral function (deep coma, wide pupils, absence of reflexes and spontaneous respiration, isoelectric EEG, etc.) during a variable period of time. However, the absence of vital signs of an organ, even for prolonged periods, is no proof of its death. The death of an organ can only be considered as proved by the demonstration that this organ has remained completely deprived of its blood flow during a period of time that surpasses its ability to survive circulatory arrest. In the case of the brain, the permanent absence of clearance of a radioactive tracer deposed within the brain is considered to demonst…

Cetacea Cephalica. Circolazione encefalica,densità neuronale e sviluppo cranico nei delfini.

2008

Lactate and glucose as energy substrates and their role in traumatic brain injury and therapy

2009

Traumatic brain injury is a leading cause of disability and mortality worldwide, but no new pharmacological treatments are clinically available. A key pathophysiological development in the understanding of traumatic brain injury is the energy crisis derived from decreased cerebral blood flow, increased energy demand and mitochondrial dysfunction. Although still controversial, new findings suggest that brain cells try to cope in these conditions by metabolizing lactate as an energy substrate ‘on-demand’ in lieu of glucose. Experimental and clinical data suggest that lactate, at least when exogenously administered, is transported from astrocytes to neurons for neuronal utilization, essential…