Search results for " circulation"

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…

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 …

Cerebral venous outflow in the prone position

2020

Anticoagulation in splanchnic and cerebral vein thrombosis: Still groping in the dark.

2020

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…

A fatal iatrogenic right vertebral injury after transoral odontoidectomy and posterior cervical stabilization for a type II odontoid fracture.

2014

Abstract The authors present a singular case of an iatrogenic right vertebral artery injury, involving a 67 year-old man, who reported a type II odontoid fracture (Anderson and D'Alonzo Classification) and posterior atlantoaxial dislocation following a road traffic accident. A small injury involving the right vertebral artery occurred as a consequence of transoral odontoidectomy and posterior cervical stabilization. It was caused by bone spicules of spinal origin and their presence was confirmed by the histological section of the right vertebral artery at the level of C1–C2. The case confirms how iatrogenic vertebral artery injuries during cervical spine surgery may be potentially lethal, e…

Experimente zur Zeolithbildung durch hydrothermale Umwandlung

1974

The formation of zeolites by hydrothermal alteration has been investigated by taking trass from the Laach volcanic area as a sample. Zeolites to be found are chabazite, phillipsite and analcime, all of which originated from the same phonolitic glass. This paper aims at explaining the formation of zeolites by means of experimental alteration of the pumice with various solutions. NaOH and KOH solutions were used in the experiments, these limited the formation conditions of chabazite, phillipsite, analcime in alkaline environments. Moreover, experiments were carried out with H2O dist and with solutions that formed during the alteration of pumice by reacting with H2O. These experiments were con…

Channel Tracking Guidewire and Technique for Retrograde Approach

2020

Evaluation of the collateral circulation is critical for determining the feasibility of the retrograde approach. When assessing collateral channels it is of paramount importance to take time and review the previous angiogram carefully, for multiple potential collateral pathways, as the predominant collateral may change over time prior to the procedure. Careful review of collaterals prior to the procedure can reduce contrast and radiation dose as well as the duration of the procedure.Retrograde access to the distal vessel can be achieved via septal collaterals, epicardial collaterals (atrial channel), or (patent or occluded) coronary bypass grafts. Generally septals are used more often 65–70…

The climate change effect on the african monsoon region : evolution of the precipitation and atmospheric fields in the CMIP3 and CMIP5 simulations un…

2013

The fourth IPCC report in 2007 established the synthesis of previously published work onthe effects of climate change on global and regional scales. It shows in particular that no consensuscan be found with regard to the future of rainfall — and atmospheric dynamics- associatedwith region — African monsoon. This dissertation revisits this issue in the light of new dataand using an approach avoiding over-representation of the number of simulations available forone type of model and taking into account the diversity of models and their evolution in time :twenty general circulation models (GCMs) participating in the exercises CMIP3 (twelve GCMs)and CMIP5 (eight GCMs) under the A1B emissions sc…