A5040453377- Heart Rate Variability and Autonomic Control
- Nitric Oxide and Endothelin Effects
- Cardiac Imaging and Diagnostics
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Cardiac electrophysiology and arrhythmias
- Cardiac Ischemia and Reperfusion
- Cardiovascular Function and Risk Factors
- Cardiac Arrhythmias and Treatments
- Dark Matter and Cosmic Phenomena
- Cardiac Arrest and Resuscitation
- Advanced MRI Techniques and Applications
- Astrophysics and Cosmic Phenomena
- Particle Detector Development and Performance
- Eicosanoids and Hypertension Pharmacology
- Non-Invasive Vital Sign Monitoring
- Hemodynamic Monitoring and Therapy
- Renal function and acid-base balance
- Cardiovascular and exercise physiology
- Neuroscience of respiration and sleep
- Neutrino Physics Research
- Optical Imaging and Spectroscopy Techniques
- Adenosine and Purinergic Signaling
- Receptor Mechanisms and Signaling
University of Washington
2003-2018
University of Siegen
1994-2013
Clifford Chance
2011
McGill University
1999
Kawasaki Medical School
1997
Max Planck Institute for Physics
1996-1997
Max Planck Society
1997
Max Planck Innovation
1997
Folkwang University of the Arts
1994-1995
Institute for High Energy Physics
1995
Voltage-gated sodium channels composed of pore-forming α and auxiliary β subunits are responsible for the rising phase action potential in cardiac muscle, but functional roles distinct channel subtypes have not been clearly defined. Immunocytochemical studies show that principal subunit isoform Na v 1.5 is preferentially localized intercalated disks, whereas brain isoforms 1.1, 1.3, 1.6 transverse tubules. Sodium currents due to highly tetrodotoxin (TTX)-sensitive tubules small detectable...
Neither stroke volume nor external cardiac work (the integral of pressure times flow during ejection) has been considered an important correlate myocardial oxygen consumption. An initial set experiments re-examined this question independently varying heart rate, systolic blood pressure, and in seven closed-chest, anesthetized dogs. This was achieved by pacing, a control reservoir, phenylephrine infusion, adjustment arteriovenous shunts. Propranolol used to minimize changes contractility...
The role of a-receptor constriction coronary vessels in response to cardiac sympathetic activation was evaluated closed-chest, chloralose-anesthetized dogs.Cardiac produced (1) directly by intracoronary norepinephrine infusion at several different rates and (2) reflexly carotid sinus hypotension.The resulting changes blood flow myocardial oxygen consumption were recorded before after blockade with dibozane (3.0 mg/kg, iv) or phenoxybenzamine (0.5 intracoronary).The normalized metabolism...
Human plasma ATP concentration is reported in many studies as roughly 1000 nmol/L. The present study tested the hypothesis that measured lower if release from formed blood elements inhibited during sample processing. A second was pretreatment with aspirin to inhibit platelets would reduce of ATP.Blood sampled antecubital vein 20 healthy individuals 30 and 60 min after ingestion (325 mg) or placebo. Aliquots each were added usual EDTA/saline solution catabolism, a new stabilizing designed...
The sympathetic control of left circumflex coronary blood flow was studied by stellate ganglion and hypothalamic stimulation. Flow measured acutely in dogs under chloralose or pentobarbital anesthesia an electromagnetic flowmeter. Coronary vasoconstriction observed when the stimulated after blocking beta receptors with propranolol INPEA. possibility cholinergic vasodilation type found skeletal muscle examined three types experiments which occurred muscle: (1) peripheral nerve stimulation...
The role of the vagus in control coronary blood flow was studied chloralose-anesthetized dogs with open chests. Propranolol, 1.0 mg/kg iv, used for beta-receptor blockade. Heart rate maintained at a constant level atrial and ventricular pacing. Left circumflex artery measured an electromagnetic flowmeter. experimental design accounted four major determinants flow: (1) aortic pressure, (2) myocardial systolic compression, (3) alterations oxygen tension metabolism secondary to changes...
Schenkman, Kenneth A., David R. Marble, H. Burns, and Eric O. Feigl. Myoglobin oxygen dissociation by multiwavelength spectroscopy. J. Appl. Physiol. 82(1): 86–92, 1997.—Multiwavelength optical spectroscopy was used to determine the oxygen-binding characteristics for equine myoglobin. Oxygen-binding relationships as a function of tension were determined temperatures 10, 25, 35, 37, 40°C, at pH 7.0. In addition, curves 37°C 6.5, 7.0, 7.5. Equilibration achieved with myoglobin solution,...
Recent studies from this laboratory have indicated that sympathetic alpha-receptor-mediated coronary vasoconstriction can compete with local metabolic vasodilation to reduce the oxygen supply myocardium. In vitro other laboratories on isolated vessel strips suggest large epicardial vessels are dominant site of adrenergic alpha-receptor activity. study we used anesthetized, open-chest dogs test hypothesis occurs predominantly in vessels, which partially removed milieu Adrenergic beta-receptor...
The hypothesis that alpha-adrenergic coronary vasoconstriction helps maintain a uniform transmural distribution of myocardial blood flow during exercise was tested in dogs. Carotid artery loops were surgically constructed and splenectomy performed three weeks prior to study. On the day study, dog anesthetized briefly (fentanyl nitrous oxide) for percutaneous catheterization, alpha-receptors one region blocked with phenoxybenzamine (0.25 mg/kg) infused selectively into left circumflex artery....
The effect of sympathetic alpha-receptor coronary vasoconstriction on myocardial oxygen tension was studied in open- and closed-chest, chloralose-anesthetized dogs. Blood the sinus blood flow circumflex artery were continuously measured a three-part experiment. With stimulation left stellate ganglion (15 Hz, 3 msec, 4-7 v, 90-second train) under vagotomy control conditions (part 1), heart rate, pressure, increased, but decreased from 19 mm Hg to 15 Hg. In part 2, beta-receptor blockade with...
The effect of sympathetic stimulation on cerebral blood flow was investigated in dogs anesthetized with chloralose. A preparation has been developed for the moment-to-moment measurement venous outflow an electromagnetic transducer. brain's arterial supply left undisturbed. innervation vessels stimulated at stellate ganglion (3-9 v, 3 msec, and 1, 3, 6, 10, 15 Hz 60 or 90 seconds). Stimulation resulted average decrease 79.7%. During oxygen tension decreased from 93.2 to 84.9 mm Hg, carbon...
Based on observations that as cardiac output (as determined by an artificial pump) was experimentally increased the right atrial pressure decreased, Arthur Guyton and coworkers proposed interpretation represents a back restricting venous return (equal to in steady state). The idea is limiting associated "venous recoil" does work produce flow have confused physiologists clinicians for decades because Guyton's interchanges independent dependent variables. Here model data are reanalyzed clarify...
The instantaneous and continuous thickness of the left ventricular wall was measured in ten dogs with a specially designed transducer. change during "isovolumic" phase systole 11%. average increased an additional 10% ejection period systole. These values to 20% 15% respectively administration norepinephrine (approximately 0.001 mg/kg per minute). Transverse longitudinal epicardial are strains were compared strain myocardium. Assuming myocardium is incompressible, reasonable agreement found...
Vasodilation following the infusion of acetylcholine is due to release endothelium-derived relaxing factor (EDRF). However, role EDRF in neurogenic coronary vasodilation, when released outside vessel at adventitial-medial junction, has not been established. The action parasympathetic vasodilation was tested present study using a specific inhibitor synthesis, nitro-L-arginine methyl ester (L-NAME). Experiments were conducted on closed-chest, alpha-chloralose-anesthetized dogs with heart paced...
It was previously shown that red blood cells release ATP when oxygen tension decreases. acts on microvascular endothelial to produce a retrograde conducted vasodilation (presumably via gap junctions) the upstream arteriole. These observations form basis for an hypothesis of local metabolic control coronary flow due in units where myocardial extraction is high. Dogs (n = 10) were instrumented with catheters aorta and sinus, transducer placed around circumflex artery. Arterial venous plasma...
Previous studies have demonstrated competition between sympathetic alpha receptor-mediated coronary vasoconstriction and local metabolic vasodilation during activation. The present study tested if this also occurs in the presence of stenosis. In closed-chest dogs, left artery was cannulated, blood flow from aorta restricted by a moderate stenosis (70% area reduction). Intracoronary norepinephrine infusion produced vascular receptor myocardial beta Norepinephrine repeated following blockade...
The role of the carotid sinus reflex in control blood flow left circumflex coronary artery was studied nine open-chest dogs anesthetized with chloralose. Flow measured an electromagnetic flowmeter. effects bilateral common occlusion were examined a three-part experiment each dog. (1) Under vagotomy (control) conditions, both arteries resulted tachycardia, increased pressure, and decrease resistance. (2) After beta-receptor blockade propranolol, 1.0 mg/kg, hypotension still pressure but...
Dial, or 5,5-diallylbarbituric acid; mixture of pento