Search results for "Perfusion"

Pathophysiology of Cerebral Ischemia

1991

The weight of the brain amounts to only 2% of total body weight, but it receives 15% of the cardiac output and uses 20% of the oxygen consumed by the body. The energy supply is provided almost exclusively by glucose metabolism. The substrate for this is stored in the brain in the form of glucose or glycogen and is sufficient to cover the energy requirements for only about 1 min. Consequently, there is a delicate equilibrium between oxygen and nutrient supply from the blood and the energy requirements of the brain. Disturbances in neurologic function appear after a few seconds of ischemia, although they are not necessarily persistent at first.

The use of a proximal protection system, a reperfusion catheter, and new-generation mesh stents in combined endovascular therapy for a long, symptoma…

2020

Endothelial Cell Swelling and Brain Perfusion

1997

Background: Whereas the contribution of glial swelling to no-reflow conditions in the ischemic penumbra or during reperfusion after global ischemia is widely discussed, little is known about cell volume control of endothelial cells under reperfusion conditions. Methods: The effect of extracellular acidosis-a key mediator of secondary brain damage-on cell volume was studied in the GM7373 endothelial cell line. Experiments were performed at pH = 6.0 in the presence or absence of bicarbonate, and during exposure to inhibitors of specific transport systems such as ethyl isopropyl amiloride or 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid. Results: Endothelial swelling to 111.1 ± 3.4% was f…

Intraarterielle präoperative Chemotherapie fortgeschrittener Zervixkarzinome

1991

Three patients suffering from very advanced primary cancers of the cervix uteri (FIGO II B or III B) were treated. By preoperative selective perfusion of both uterine arteries, using cis-platinum alone, a distinct reduction of the tumour volume was achieved. This was demonstrated clinically and also by CAT scan and NMR technique. The elevated serum CEA and SCC levels decreased to normal values. The histomorphology of the Wertheim-Meigs specimens revealed no tumour invasion of the initially infiltrated parametria. This treatment modality has been developed to minimise the toxic side effects of the inductive (neo-adjuvant) chemotherapy for cervical cancers.

Tumor Oxygenation Under Normobaric and Hyperbaric Hyperoxia

1997

Tumor hypoxia is an important factor limiting the efficiency of sparsely ionizing ra-diation and O2-dependent chemotherapy. Since the tumor pO2 is the result of a dynamic steady state between oxygen supply and O2 consumption of the tumor tissue, hypoxia could be reduced either by increasing the O2-supply or by reducing the O2 demand of the tumor cells. The O2 supply can be improved for instance by (i) increasing the arterial oxy-gen partial pressure, (ii) improving (and homogenizing) the tumor perfusion, or (iii) en-hancing the O2 release from blood into the tissue by right-shifting the HbO2 dissociation curve. Theoretically, it should also be possible to improve tumor oxygenation by a rela…

CT Angiography as a Confirmatory Test in Brain Death

2012

Objective: From recent studies, it remains unclear whether CT angiography could be an alternative to other established ancillary tests for the diagnosis of brain death. We examined intracranial contrast enhancement in CT angiography after clinically established brain death and compared the results with EEG and TCD findings.

EpCAM and microvascular obstruction in patients with STEMI: a cardiac magnetic resonance study

2021

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” Bachground. Microvascular obstruction (MVO) is negatively associated with cardiac structure and worse prognosis after ST-segment elevation myocardial infarction (STEMI). Epithelial cell adhesion molecule (EpCAM), involved in endothelium adhesion, is an understudied area in the MVO setting. Purpose. We aimed to evaluate whether EpCAM is associated with the appearance of cardiac magnetic resonance (CMR)-derived MVO and long-term systolic function in reperfused STEMI. Methods.…

Effect of ischemic postconditioning on microvascular obstruction in reperfused myocardial infarction. Results of a randomized multicenter study in pa…

2013

Purpose: Ischemic Postconditioning (PCON) appears as a potentially beneficial tool to complement primary angioplasty in ST-segment elevation myocardial infarction (STEMI). We evaluated the impact of PCON on Microvascular Obstruction (MVO) both in patients and in a highly controlled swine model. Methods: In a multicenter study, 101 patients with a first STEMI were randomized to undergo primary angioplasty followed by PCON or primary angioplasty alone (non-PCON). MVO (lack of contrast uptake in the core of the hyperenhanced infarcted area) was quantified in late enhancement cardiac magnetic resonance imaging. In an anterior STEMI swine model based on a 90-min angioplasty balloon coronary occl…

Left ventricular non-compaction cardiomyopathy in children: Is segmental fibrosis the cause of tissue Doppler alterations and of EF reduction?

2009

Noncompaction of the ventricular myocardium (LVNC) is a rare congenital cardiomyopathy resulting from an arrest in normal endomyocardial embryogenesis. In 2002 Jenni et al. [Jenni R, Wyss CA, Oechslin EN, Kaufmann PA. Isolated ventricular noncompaction is associated with coronary microcirculatory dysfunction. J Am Coll Cardiol 2002; 39:450-454.] reported a microvascular dysfunction in 12 patients affected by non compaction: areas of restricted myocardial perfusion have been documented by scintigraphy, suggesting a reduction of Coronary flow reserve. McMahon et al reported in a recent article a reduction of TD velocities in children with noncompaction of the left ventricle, compared with nor…

Mathematical Modelling of Local Regulation of Blood Flow by Veno-Arterial Diffusion of Vasoactive Metabolites

1997

It is widely accepted that vasoactive substances which are consumed or produced by tissue metabolism play a role in the adjustment of local perfusion rate to the metabolic needs of the tissue. In order to evoke a response of the vascular system, these substances — in the following for simplicity denoted by “vasodilators” even though oxygen, for example, is a vasoconstrictor — need to get into close contact with the small arterioles which represent the most powerful effectors in perfusion control. On the other hand, tissue sites in which supply with nutrients is most critical (“lethal corners”) and in which a vasodilator signal may be generated earliest, are located hundreds of µm away from …