Search results for "Blood"
showing 10 items of 5199 documents
Resting myocardial blood flow quantification using contrast-enhanced magnetic resonance imaging in the presence of stenosis: A computational fluid dy…
2015
Purpose: The extent to which atherosclerotic plaques affect contrast agent (CA) transport in the coronary arteries and, hence, quantification of myocardial blood flow (MBF) using magnetic resonance imaging (MRI) is unclear. The purpose of this work was to evaluate the influence of plaque induced stenosis both on CA transport and on the accuracy of MBF quantification. Methods: Computational fluid dynamics simulations in a high-detailed realistic vascular model were employed to investigate CA bolus transport in the coronary arteries. The impact of atherosclerosis was analyzed by inserting various medium- to high-grade stenoses in the vascular model. The influence of stenosis morphology was ex…
Transkranielle Dopplersonographie bei Kopf-Hals-Tumoren*
1991
Transcranial Doppler ultrasound (TCD) recording is a non-invasive diagnostic procedure for the evaluation of the cerebral collateral flow in patients, in whom therapeutic ligation or resection of the common and/or internal carotid artery is planned. Patients are first examined under resting conditions, and then under manual compression of the ipsilateral carotid artery. Since January 1989, 31 ENT and neurosurgical patients have been examined. In all patients an immediate decrease in flow velocity in the middle cerebral artery (mca) of about 25% to 90% was recorded. In 42.8% of the patients the mca flow velocity reached 90% or more of its value under normal conditions within a short period. …
Evaluation von Nierenarterienstenosen: Vergleich von Angiographie mit invasiver Blutdruckmessung und Doppler-Sonographie
2000
Ziel: Der bei einer Nierenarterien-Angioplastie angiographisch gemessene Stenosegrad soll mit dem transstenotischen Blutdruck-Gradienten und dem prainterventionellen dopplersonographischen Befund verglichen werden. Methoden: Anhand von insgesamt 46 Nierenarterienstenosen bei 35 Patienten mit renovaskularer Hypertonie werden die angiographisch-morphologischen Befunde („linearer”, „geometrischer” und „densitometrischer” Stenosegrad) mit der invasiven transstenotischen Blutdruckmessung und den prainterventionellen Doppler-Befunden verglichen. Ergebnisse: Alle angiographisch bestimmten Stenosegrade korrelieren - masig - mit den transstenotischen Druckgradienten (Korrelationskoeffizienten: 0,67 …
[CT-angiography in carotid stenosis].
1997
Purpose: Prospective evaluation of the accuracy of CT angiography (CTA) with different postprocessing for extracranial carotid artery in comparison with DSA. Method: one hundred patients were studied with standarized CTA. For postprocessing, MPR, MIP, and 3D reconstruction based on segmentation with upper and lower threshold were used. Intravascular density profiles were considered. All CTA studies were correlated with intra-arterial angiography. The degree and classification of stenoses was determined using the guidelines established by the NASCET collaborators. Results: Measurement of stenosis was possible by MPR in 82.5 %, by MIP in 85 %, and 3D in 100 %. Correct classification was found…
THE METABOLIC SYNDROME IN HYPERTENSION
2019
The metabolic syndrome (MS) is currently considered to be a cluster of metabolic and cardiovascular risk factors including blood pressure elevation. A higher risk to develop hypertension in MS subjects with high-normal blood pressure has been observed and, when hypertension is established, seems to be what confers a higher cardiovascular risk on top of the risk induced by blood pressure elevation. Therefore, assessment of MS components can result in clinical utility strategy to manage hypertension based on individual risk. The main mechanisms for blood pressure elevation include overactivity of the sympathetic and the reninangiotensin system, abnormal renal sodium handling, and endothelial …
Druckentlastung im Aneurysmasack nach endovaskulärer Therapie von Aortenaneurysmen*
2000
PURPOSE Stent grafting of aortic aneurysms should result in relief of pressure within the excluded aneurysmal sac, however confirming data are not available. This study evaluates the intra-extraluminal pressure translation and translation of maximum pressure increase (dp/dtmax) into the excluded aneurysmal sac after endovascular treatment of experimental aortic aneurysms. MATERIALS AND METHODS Experimental autologous aneurysms were created surgically using a patch from the sheath of the rectus abdominis muscle in 12 mongrel dogs. After 12 weeks reconvalescence, endovascular treatment was performed viafemoral access using dacron-covered nitinol stents. Spiral CT and angiography were performe…
Klassifikation und Therapie von Endolecks nach endovaskulärer Behandlung von abdominellen Aortenaneurysmen
2005
This article describes the classification of endoleaks after endovascular treatment of abdominal aortic aneurysms, thereby summarizing the most important problems of this endovascular technique. The correct classification of endoleaks is a prerequisite for interdisciplinary discussion. It is indispensable for professional reporting of the pathological findings and for the decision making as to the adequate treatment of endoleaks. Irrespective of the types of stent graft and property of the material, five endoleak types are defined in the literature: leakage at the anchor sites (type I); leakage due to collateral arteries (type II); defective stent grafts (type III); leakage due to porosity …
Influence of blood sampling from venipunctures and catheter systems on serial determinations of prothrombin activation fragment 1 + 2 and thrombin-an…
1993
To evaluate the influence of different blood sampling techniques on test results of thrombin-antithrombin III complex (TAT) and prothrombin fragment 1 + 2 (F1 + 2) serial determinations were performed. In six groups of nonrandomized patients (ten patients each) the concentrations of the coagulation markers of blood samples from central catheters (internal jugular, caval, Shaldon, pulmonary artery) and peripheral cannulas (17G and 18G) were compared with those of blood samples obtained simultaneously from direct venipunctures of the contralateral arm. Medians and 25th-75th percentiles of TAT and F1 + 2 concentrations of plasmas obtained from central catheters were not different from those ta…
Human antiphospholipid antibodies induce TNFα in monocytes via Toll-like receptor 8
2009
The antiphospholipid syndrome (APS) is characterized by recurrent arterial and/or venous thromboses, pregnancy loss and the presence of antiphospholipid antibodies (aPL). One of the discussed mechanisms of this thrombotic activity in APS patients is attributed to TNFalpha secretion in monocytes after aPL stimulation. To investigate this mechanism in detail, we employed a monoclonal aPL and IgG fractions of APS patients for stimulation of human peripheral monocytes. Stimulation with this monoclonal aPL resulted in an increased expression and secretion of TNFalpha, caused by specific upregulation of TLR8 mRNA and protein expression levels. To confirm the specificity of this finding we could d…
Endothelin action on goat cerebral arteries.
1990
Abstract Cumulative application of endothelin-1 (human) markedly constricted goat isolated cerebral arteries in a concentration-dependent manner. Contractile responses were not affected by removal of endothelial cells. Removal of extracellular calcium or addition of the calcium channel blocker nicardipine (10−7 M) failed to abolish responses to endothelin. The results suggest that the endothelium-independent constriction of cerebral arteries produced by endothelin cannot be explained solely by voltage-dependent calcium channels. The contractile responses are likely to be mediated by stimulation of specific receptors for this peptide.