Die Kardiologen und die Zukunft ihres Fachs

Viewpoint Zur Frage der Zertifizierung von Spezialfächern der Kardiologie Die Kardiologen und die Zukunft ihres Fach

Management of Patients with Carotid Artery Stenosis

Abstract : A stenosis of the internal carotid artery may cause 10-20% of all ischemic strokes. Duplex ultrasound is the diagnostic cornerstone, and CT angiography or MR angiography may be used to confirm the severity of the stenosis or prior to revascularization. Catheter-based digital subtraction angiography is rarely needed for diagnostic purposes. In symptomatic patients, carotid revascularization is indicated in the presence of a stenosis ≥ 50%. In asymptomatic patients, the indication for revascularization based on randomized trials is given at ≥ 60% stenosis, as long as the estimated perioperative death or stroke risk is < 3%. In clinical practice, however, asymptomatic stenoses are usually treated only if luminal narrowing exceeds 70-80% and the patient has a life expectancy of at least 5 years. The choice of the revascularization strategy (endarterectomy vs. stenting) should be based on the patient's surgical risk profile and on the locally available expertise. Independently of the revascularization option, carotid artery stenosis patients remain at risk of cardiovascular events because of the high prevalence of associated coronary artery disease. A broad disease management focusing on risk factor and lifestyle modification may impact quality and duration of life of these patients to a greater extent than the revascularization procedure itsel

Human endothelial dysfunction: EDRFs

Since the detection of nitric oxide two and a half decades ago, there has been an incredible boost in endothelial function research, which is fascinating the research community. Physiologically, endothelial cells synthesize a number of vasoactive substances. In particular, several endothelium-derived relaxing factors (EDRFs) have been characterized, whereby nitric oxide is the most important. In humans, endothelial dysfunction is one of the first clinically detectable alterations in the development of atherosclerosis and is characterized by an imbalance in the release of vasoactive substances. Thus, it is the aim of this article to give an overview about endothelial function in humans, to summarize the different possibilities to assess endothelial function in this species, and to give an overview of the role of EDRFs in different cardiovascular disease

Physics issues in simulations with dynamical overlap fermions

We discuss the impact of various improvements on simulations of dynamical overlap fermions using the Hybrid Monte Carlo algorithm. We focus on the usage of fat links and multiple pseudo-fermion fields.Comment: 14 pages, 10 figure

Timing and Precision of Spike Initiation in Layer V Pyramidal Cells of the Rat Somatosensory Cortex

The timing and location of action potential initiation in layer V pyramidal cells of the rat somatosensory cortex depends on different ligand-gated and intrinsic conductances. In order to assess the shunting effect of GABAA receptor activation and Ih on the summative properties of these neurons, we recorded simultaneously from their somata and dendrites and induced combined excitatory and inhibitory postsynaptic potentials using extracellular stimulation. Three major consequences of GABAA receptor activation on the integration properties were found: (i) the action potential could be initiated in the distal apical dendrite, if GABAA receptors were simultaneously activated in the soma; (ii) GABAA receptor activation narrowed the time window for suprathreshold summation of two coincident excitatory synaptic inputs by a factor of 3.4; and (iii) uneven weights of the GABAergic components between two inputs could lead to unbalanced shunting and consequently to a time shift in the peak of the coincidence detection window. Blockade of Ih practically abolished coincidence detection within a time window of 30 ms. Location of spike initiation and summation of coincident inputs in pyramidal cells is determined by at least two shunting mechanisms: activation of the presynaptic inhibitory network and modulation of Ih as a function of the postsynaptic membrane potentia