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Charles Franklin Starmer

Professor Emeritus of Computer Science
Computer Science
Duke Box 2741, Durham, NC 27710
2424 Erwin Road Ste G04, Hock Plaza Ste G04 Duke Box 27, Durham, NC 27705

Selected Publications


SAN DIEGO BIOMEDICAL SYMPOSIUM, 1971, PROCEEDINGS, v 10.

Journal Article · January 1, 2020 Following is a continuation of the listing of papers presented: Automatic Calibration of On-Line Respiratory Measurements. By J. O. Beaumont and W. A. Radke. System for Storage and Retrieval of Textual and Numeric Data Collected During Patient Monitoring. ... Cite

SAN DIEGO BIOMEDICAL SYMPOSIUM, 1971, PROCEEDINGS, v 10.

Journal Article · January 1, 2017 Following is a continuation of the listing of papers presented: Automatic Calibration of On-Line Respiratory Measurements. By J. O. Beaumont and W. A. Radke. System for Storage and Retrieval of Textual and Numeric Data Collected During Patient Monitoring. ... Cite

Smartphone spectrophotometer for point-of-care diagnostics in low-resource settings

Conference IEEE Region 10 Humanitarian Technology Conference, R10-HTC 2015 - co-located with 8th International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment and Management, HNICEM 2015 · January 25, 2016 Colorimetry based point-of-care diagnostics provide an inexpensive technique for healthcare and environmental monitoring during disaster relief operations. Conventional equipments for measuring colorimetric assays are bulky and expensive, making them unsui ... Full text Cite

Feedback stabilization of control policy selection in data/knowledge based systems

Journal Article Proceedings - International Conference on Data Engineering · September 14, 2015 Knowledge and/or data-based decision support systems can be viewed as complex control systems designed to optimize a desired criterion. As such, they aid users in transforming objects with an initial state vector to some desired outcome state by applicatio ... Full text Cite

Non-uniform dispersion of the source-sink relationship alters wavefront curvature.

Journal Article PloS one · January 2013 The distribution of cellular source-sink relationships plays an important role in cardiac propagation. It can lead to conduction slowing and block as well as wave fractionation. It is of great interest to unravel the mechanisms underlying evolution in wave ... Full text Cite

Exploring the role of pH in modulating the effects of lidocaine in virtual ischemic tissue.

Journal Article American journal of physiology. Heart and circulatory physiology · November 2010 Lidocaine is a class I antiarrhytmic drug that blocks Na(+) channels and exists in both neutral and charged forms at a physiological pH. In this work, a mathematical model of pH and the frequency-modulated effects of lidocaine has been developed and incorp ... Full text Cite

Exploring reentrant arrhythmias with numerical experiments: generic properties and model complexity.

Journal Article Journal of cardiovascular electrophysiology · June 2009 Full text Cite

Investigative methods and tools: Developing an integrated approach to critical thinking, evidence-based medicine and biostatistics

Journal Article Singapore General Hospital Proceedings · December 1, 2008 Each day's work, whether a clinician, researcher or homemaker, focuses on investigative strategies and problem solving. Investigative methods and problem solving are rarely addressed formally in a medical school curriculum. Our goal with Investigative Meth ... Cite

The role of intrinsic and induced vulnerability in electrically induced cardiac arrhythmias.

Journal Article Journal of cardiovascular electrophysiology · December 2006 Full text Cite

Slow sodium channel inactivation and use-dependent block modulated by the same domain IV S6 residue.

Journal Article J Membr Biol · September 2005 Featured Publication Voltage- and/or conformation-dependent association and dissociation of local anesthetic-class drugs from a putative receptor site in domain IV S6 of the sodium channel and slow conformation transitions of the drug-associated channel have been proposed as m ... Full text Link to item Cite

What happens when cardiac Na channel function is compromised? 2. Numerical studies of the vulnerable period in tissue altered by drugs.

Journal Article Cardiovasc Res · March 15, 2003 OBJECTIVE: The fate of an impulse arising from stimulation is determined by the ability of the wave front to recruit sufficient Na channels from adjacent cells. Previous numerical studies of mutant Na channels revealed both the velocity of a conditioning w ... Full text Link to item Cite

Ischemic modulation of vulnerable period and the effects of pharmacological treatment of ischemia-induced arrhythmias: a simulation study.

Journal Article IEEE transactions on bio-medical engineering · February 2003 First identified in the 1930s (Ferris et al., 1936 and Wiggers and Wegria, 1939), the concept of vulnerability applies perfectly to biological oscillators. We can safely say that vulnerability is an inherent property of any excitable media. The duration of ... Full text Cite

What happens when cardiac Na channels lose their function? 1--numerical studies of the vulnerable period in tissue expressing mutant channels.

Journal Article Cardiovasc Res · January 2003 Featured Publication OBJECTIVE: The vulnerable period (VP) defines an interval during which premature impulses can trigger reentrant arrhythmias leading to ventricular fibrillation and sudden death. The mechanistic basis of the success or failure of impulse propagation during ... Full text Link to item Cite

Slow conduction within infarct scars as a source of high-frequency oscillations in the QRS signal

Journal Article Computers in Cardiology · January 1, 2003 We propose a detailed explanation of increased variability of high-frequency (> 100 Hz) components within the QRS observed in post-myocardial infarction patients, reported in recent studies of real high-resolution ECGs. Using mathematical models of single, ... Full text Cite

Hitting a moving target: toward a compliance-driven patient record.

Journal Article Journal of the American Medical Informatics Association : JAMIA · November 2002 Full text Cite

Long QT syndrome, Brugada syndrome, and conduction system disease are linked to a single sodium channel mutation.

Journal Article J Clin Invest · October 2002 The function of the 12 positive charges in the 53-residue III/IV interdomain linker of the cardiac Na(+) channel is unclear. We have identified a four-generation family, including 17 gene carriers with long QT syndrome, Brugada syndrome, and conduction sys ... Full text Link to item Cite

How antiarrhythmic drugs increase the rate of sudden cardiac death

Journal Article International Journal of Bifurcation and Chaos in Applied Sciences and Engineering · September 1, 2002 Two large clinical trials of drugs that exhibited significant antiarrhythmic properties in single cells were found to increase the rate of sudden cardiac death in patients by two to three fold over untreated patients. We hypothesized that premature excitat ... Full text Cite

A quantitative analysis of variability of the electrocardiograms typical of polymorphic arrhythmias

Journal Article Biofizika · December 1, 2001 A new approach to the analysis of variability of electrocardiograms (ECGs) typical of polymorphic arrhythmias is developed. In these ECGs, separate QRS complexes can be often hardly identified. As a result, the mathematical methods that have been elaborate ... Cite

[Quantitative analysis of variability of electrocardiograms typical for polymorphic arrhythmias].

Journal Article Biofizika · March 2001 A new approach to the analysis of variability of electrocardiograms (ECGs) typical of polymorphic arrhythmias is developed. In these ECGs, separate QRS complexes can be often hardly identified. As a result, the mathematical methods that have been elaborate ... Cite

SAN DIEGO BIOMEDICAL SYMPOSIUM, 1971, PROCEEDINGS, v 10.

Journal Article · January 1, 2020 Following is a continuation of the listing of papers presented: Automatic Calibration of On-Line Respiratory Measurements. By J. O. Beaumont and W. A. Radke. System for Storage and Retrieval of Textual and Numeric Data Collected During Patient Monitoring. ... Cite

SAN DIEGO BIOMEDICAL SYMPOSIUM, 1971, PROCEEDINGS, v 10.

Journal Article · January 1, 2017 Following is a continuation of the listing of papers presented: Automatic Calibration of On-Line Respiratory Measurements. By J. O. Beaumont and W. A. Radke. System for Storage and Retrieval of Textual and Numeric Data Collected During Patient Monitoring. ... Cite

Smartphone spectrophotometer for point-of-care diagnostics in low-resource settings

Conference IEEE Region 10 Humanitarian Technology Conference, R10-HTC 2015 - co-located with 8th International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment and Management, HNICEM 2015 · January 25, 2016 Colorimetry based point-of-care diagnostics provide an inexpensive technique for healthcare and environmental monitoring during disaster relief operations. Conventional equipments for measuring colorimetric assays are bulky and expensive, making them unsui ... Full text Cite

Feedback stabilization of control policy selection in data/knowledge based systems

Journal Article Proceedings - International Conference on Data Engineering · September 14, 2015 Knowledge and/or data-based decision support systems can be viewed as complex control systems designed to optimize a desired criterion. As such, they aid users in transforming objects with an initial state vector to some desired outcome state by applicatio ... Full text Cite

Non-uniform dispersion of the source-sink relationship alters wavefront curvature.

Journal Article PloS one · January 2013 The distribution of cellular source-sink relationships plays an important role in cardiac propagation. It can lead to conduction slowing and block as well as wave fractionation. It is of great interest to unravel the mechanisms underlying evolution in wave ... Full text Cite

Exploring the role of pH in modulating the effects of lidocaine in virtual ischemic tissue.

Journal Article American journal of physiology. Heart and circulatory physiology · November 2010 Lidocaine is a class I antiarrhytmic drug that blocks Na(+) channels and exists in both neutral and charged forms at a physiological pH. In this work, a mathematical model of pH and the frequency-modulated effects of lidocaine has been developed and incorp ... Full text Cite

Exploring reentrant arrhythmias with numerical experiments: generic properties and model complexity.

Journal Article Journal of cardiovascular electrophysiology · June 2009 Full text Cite

Investigative methods and tools: Developing an integrated approach to critical thinking, evidence-based medicine and biostatistics

Journal Article Singapore General Hospital Proceedings · December 1, 2008 Each day's work, whether a clinician, researcher or homemaker, focuses on investigative strategies and problem solving. Investigative methods and problem solving are rarely addressed formally in a medical school curriculum. Our goal with Investigative Meth ... Cite

The role of intrinsic and induced vulnerability in electrically induced cardiac arrhythmias.

Journal Article Journal of cardiovascular electrophysiology · December 2006 Full text Cite

Slow sodium channel inactivation and use-dependent block modulated by the same domain IV S6 residue.

Journal Article J Membr Biol · September 2005 Featured Publication Voltage- and/or conformation-dependent association and dissociation of local anesthetic-class drugs from a putative receptor site in domain IV S6 of the sodium channel and slow conformation transitions of the drug-associated channel have been proposed as m ... Full text Link to item Cite

What happens when cardiac Na channel function is compromised? 2. Numerical studies of the vulnerable period in tissue altered by drugs.

Journal Article Cardiovasc Res · March 15, 2003 OBJECTIVE: The fate of an impulse arising from stimulation is determined by the ability of the wave front to recruit sufficient Na channels from adjacent cells. Previous numerical studies of mutant Na channels revealed both the velocity of a conditioning w ... Full text Link to item Cite

Ischemic modulation of vulnerable period and the effects of pharmacological treatment of ischemia-induced arrhythmias: a simulation study.

Journal Article IEEE transactions on bio-medical engineering · February 2003 First identified in the 1930s (Ferris et al., 1936 and Wiggers and Wegria, 1939), the concept of vulnerability applies perfectly to biological oscillators. We can safely say that vulnerability is an inherent property of any excitable media. The duration of ... Full text Cite

What happens when cardiac Na channels lose their function? 1--numerical studies of the vulnerable period in tissue expressing mutant channels.

Journal Article Cardiovasc Res · January 2003 Featured Publication OBJECTIVE: The vulnerable period (VP) defines an interval during which premature impulses can trigger reentrant arrhythmias leading to ventricular fibrillation and sudden death. The mechanistic basis of the success or failure of impulse propagation during ... Full text Link to item Cite

Slow conduction within infarct scars as a source of high-frequency oscillations in the QRS signal

Journal Article Computers in Cardiology · January 1, 2003 We propose a detailed explanation of increased variability of high-frequency (> 100 Hz) components within the QRS observed in post-myocardial infarction patients, reported in recent studies of real high-resolution ECGs. Using mathematical models of single, ... Full text Cite

Hitting a moving target: toward a compliance-driven patient record.

Journal Article Journal of the American Medical Informatics Association : JAMIA · November 2002 Full text Cite

Long QT syndrome, Brugada syndrome, and conduction system disease are linked to a single sodium channel mutation.

Journal Article J Clin Invest · October 2002 The function of the 12 positive charges in the 53-residue III/IV interdomain linker of the cardiac Na(+) channel is unclear. We have identified a four-generation family, including 17 gene carriers with long QT syndrome, Brugada syndrome, and conduction sys ... Full text Link to item Cite

How antiarrhythmic drugs increase the rate of sudden cardiac death

Journal Article International Journal of Bifurcation and Chaos in Applied Sciences and Engineering · September 1, 2002 Two large clinical trials of drugs that exhibited significant antiarrhythmic properties in single cells were found to increase the rate of sudden cardiac death in patients by two to three fold over untreated patients. We hypothesized that premature excitat ... Full text Cite

A quantitative analysis of variability of the electrocardiograms typical of polymorphic arrhythmias

Journal Article Biofizika · December 1, 2001 A new approach to the analysis of variability of electrocardiograms (ECGs) typical of polymorphic arrhythmias is developed. In these ECGs, separate QRS complexes can be often hardly identified. As a result, the mathematical methods that have been elaborate ... Cite

[Quantitative analysis of variability of electrocardiograms typical for polymorphic arrhythmias].

Journal Article Biofizika · March 2001 A new approach to the analysis of variability of electrocardiograms (ECGs) typical of polymorphic arrhythmias is developed. In these ECGs, separate QRS complexes can be often hardly identified. As a result, the mathematical methods that have been elaborate ... Cite

Quantitative analysis of variability of electrocardiograms typical for polymorphic arrhythmias

Journal Article Biofizika · March 1, 2001 A new approach to the analysis of variability of electrocardiograms (ECGs) typical of polymorphic arrhythmias is developed. In these ECGs, separate QRS complexes can be often hardly identified. As a result, the mathematical methods that have been elaborate ... Cite

A theoretical analysis of acute ischemia and infarction using ECG reconstruction on a 2-D model of myocardium.

Journal Article IEEE transactions on bio-medical engineering · January 2001 We developed a two-dimensional ventricular tissue model in order to probe the determinants of electrocardiographic (ECG) morphology during acute and chronic ischemia. Hyperkalemia was simulated by step changes in [K+]out, while acidosis was induced by redu ... Full text Cite

Block of wild-type and inactivation-deficient cardiac sodium channels IFM/QQQ stably expressed in mammalian cells.

Journal Article Biophys J · December 2000 The role of inactivation as a central mechanism in blockade of the cardiac Na(+) channel by antiarrhythmic drugs remains uncertain. We have used whole-cell and single channel recordings to examine the block of wild-type and inactivation-deficient mutant ca ... Full text Link to item Cite

Antiarrhythmic drug effect analysis on a model of cardiac fiber

Journal Article Computers in Cardiology · December 1, 2000 Pharmacological treatment of cardiac arrhythmias still arises serious questions concerning both efficacy and safety. CAST failure as well as classification based on functional characteristics revealed the arrhythmogenic potential of both class I and class ... Cite

Stationary pulses and wave front formation in an excitable medium

Journal Article Progress of Theoretical Physics Supplement · January 1, 2000 In an excitable medium, the method of phase plane analysis of ODE reductions is often used to separate suprathreshold disturbances that collapse from disturbances that expand and result in a propagating front. Following this approach, we study here pulse f ... Full text Cite

Modeling of ventricular tissue and ECG reconstruction in acute and chronic ischemia

Journal Article Computers in Cardiology · December 1, 1999 A realistic evolution of ischemia from coronary artery occlusion to myocardial infarction is investigated in order to identify the relationship between micro level changes and the surface ECG. Based on the available experimental results, a complete descrip ... Cite

beta-Adrenergic action on wild-type and KPQ mutant human cardiac Na+ channels: shift in gating but no change in Ca2+:Na+ selectivity.

Journal Article Cardiovasc Res · May 1999 OBJECTIVE: Prior studies of the modulation of the Na+ current by sympathetic stimulation have yielded controversial results. Separation of the Na+ and Ca2+ currents poses a problem in myocyte preparations. The gating of cloned Na+ channels is different in ... Full text Link to item Cite

Action potential propagation in ischemic cardiac tissue: A theoretical computer modeling

Journal Article Computers in Cardiology · December 1, 1998 In order to identify generic mechanisms for altering the ECG during ischemia, we explored changes in the action potential propagation during different ischemic conditions using simple cellular models. Based on the Beeler-Reuter and Lou-Rudy I cellular mode ... Cite

[Slow excitation waves and mechanisms of polymorphic ventricular tachycardia in an experimental model: isolated walls of the right ventricle from rabbit and squirrel].

Journal Article Biofizika · November 1998 The mechanism of polymorphic disturbances of the heart rhythm is studied on an experimental model, isolated ventricular preparations of ground squirrel and rabbit. Polymorphic arrhythmias are identified from habitus of the isolated preparation pseudoECGs m ... Cite

Slow excitation waves and mechanisms of polymorphic ventricular tachycardia in an experimental model: isolated walls of the right ventricle from rabbit and squirrel

Journal Article Biofizika · November 1, 1998 The mechanism of polymorphic disturbances of the heart rhythm is studied on an experimental model, isolated ventricular preparations of ground squirrel and rabbit. Polymorphic arrhythmias are identified from habitus of the isolated preparation pseudoECGs m ... Cite

Multiple effects of KPQ deletion mutation on gating of human cardiac Na+channels expressed in mammalian cells.

Journal Article Am J Physiol Heart Circ Physiol · May 1, 1998 Several aspects of the effect of the KPQ deletion mutation on Na+channel gating remain unresolved. We have analyzed the kinetics of the early and late currents by recording whole cell and single-channel currents in a human embryonic kidney (HEK) cell line ... Full text Link to item Cite

Multiple effects of KPQ deletion mutation on gating of human cardiac Na+ channels expressed in mammalian cells

Journal Article American Journal of Physiology - Heart and Circulatory Physiology · May 1, 1998 Several aspects of the effect of the KPQ deletion mutation on Na+ channel gating remain unresolved. We have analyzed the kinetics of the early and late currents by recording whole cell and single-channel currents in a human embryonic kidney (HEK) cell line ... Cite

Slow Excitation Waves and Mechanisms of Polymorphic Ventricular Tachycardia in the Experimental Model: Isolated Walls of Rabbit and Ground Squirrel Right Ventricle

Journal Article Biofizika · January 1, 1998 The mechanism of polymorphic disturbances of the heart rhythm is studied on an experimental model, isolated ventricular preparations of ground squirrel and rabbit. Polymorphic arrhythmias are identified from habitus of the isolated preparation pseudoECGs m ... Cite

Boundary-layer analysis of a spiral wave core

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 1997 The size of a circular spiral wave core is predicted on the basis of a boundary layer analysis of a spiral wave tip. Dependencies of a spiral core radius on medium parameters are found analytically and numerically for the FitzHugh-Nagumo and Beeler-Reuter ... Cite

[A system for computer visualization of excitation wave propagation in the myocardium].

Journal Article Biofizika · March 1997 A method of computer-aided visualization of autowave vortices on the cardiac tissue surface is developed. The software for research into autowave vortex evolution is designed, which allowed an adequate presentation of excitation propagation along complex t ... Cite

A system for computer visualization of excitation wave propagation in the myocardium

Journal Article Biofizika · March 1, 1997 A method of computer-aided visualization of autowave vortices on the cardiac tissue surface is developed. The software for research into autowave vortex evolution is designed, which allowed an adequate presentation of excitation propagation along complex t ... Cite

The cardiac vulnerable period and reentrant arrhythmias: targets of anti- and proarrhythmic processes.

Journal Article Pacing and clinical electrophysiology : PACE · February 1997 Because sudden cardiac death is usually preceded by a reentrant arrhythmia, the precipitating arrhythmia must be multicellular in origin. Therefore clinicians seeking to reduce the incidence of reentrant arrhythmias in their patients with antiarrhythmic dr ... Full text Cite

Common mechanism links spiral wave meandering and wave-front–obstacle separation

Journal Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics · January 1, 1997 Spiral waves rotate either around a circular core or meander, inscribing a noncircular pattern. The medium properties determining the transition of meandering were found to be equivalent to those defining the transition from wave tip separation and attachm ... Full text Cite

Boundary-layer analysis of a spiral wave core: Spiral core radius and conditions for the tip separation from the core boundary

Journal Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics · January 1, 1997 The size of a spiral core is predicted on the basis of a boundary-layer analysis of a spiral tip in the nonkinematic limit. Dependencies of a spiral core radius on medium parameters are found analytically and numerically for two models of excitable media. ... Full text Cite

A system for computer-aided visualization of propagation of excitation waves in myocardium

Journal Article Biofizika · January 1, 1997 A method of computer-aided visualization of autowave vortices on the cardiac tissue surface is developed. The software for research into autowave vortex evolution is desigened, which allowed an adequate presentation of excitation propagation along complex ... Cite

The role of inactivation in open-channel block of the sodium channel: studies with inactivation-deficient mutant channels.

Journal Article Mol Pharmacol · December 1996 Inactivation has been implicated as an important determinant of the block of Na+ channel by local anesthetic-class drugs. This proposition has been difficult to examine because agents used to modify inactivation change other channel properties and both ina ... Link to item Cite

Splitting of the back front of propagating pulse of excitation

Journal Article Biofizika · December 1, 1996 A new type of unstability of action potential propogating in spatially inhomogenious electrically excitable media is announced. Numerical experiments with the FitzHugh-Nagumo model show that if the medium contains a region where membrane slow, outward curr ... Cite

Spiral wave meandering and wavefront-obstacle separation

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 1996 For reentrant arrhythmias, we show that the meandering transition is determined by the medium conditions for spiral wave tip attachment-separation from an unexcitable strip of thickness that is comparable with the wavefront thickness. ... Cite

Spiral wave meandering, wavefront - Obstacle separation and cardiac arrhythmias

Journal Article Computers in Cardiology · December 1, 1996 Spiral wave tips rotate either around a circular core or meander, inscribing a non-circular pattern. The transition to meandering was found to be equivalent to the transition from wave tip separation to wave tip attachment around the end of an unexcitable ... Cite

Boundary-layer analysis of waves propagating in an excitable medium: Medium conditions for wave-front-obstacle separation.

Journal Article Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics · July 1996 Full text Cite

Wavelet formation in excitable cardiac tissue: the role of wavefront-obstacle interactions in initiating high-frequency fibrillatory-like arrhythmias.

Journal Article Biophysical journal · February 1996 High-frequency arrhythmias leading to fibrillation are often associated with the presence of inhomogeneities (obstacles) in cardiac tissue and reduced excitability of cardiac cells. Studies of antiarrhythmic drugs in patients surviving myocardial infarctio ... Full text Cite

Cardiac transient outward potassium current: a pulse chemistry model of frequency-dependent properties.

Journal Article Am J Physiol · January 1996 Recent voltage-clamp studies of isolated myocytes have demonstrated widespread occurrence of a transient outward current (I(to)) carried by potassium ions. In the canine ventricle, this current is well developed in epicardial cells but not in endocardial c ... Full text Link to item Cite

Spiral tip movement: The role of the action potential wavelength in polymorphic cardiac arrhythmias

Journal Article International Journal of Bifurcation and Chaos in Applied Sciences and Engineering · January 1, 1996 Sudden cardiac death is often preceded by re-entrant (spiral wave) tachyarrhythmias associated with a prolongation of the action potential wavelength. Potassium channel blockade, hypokalemia and genetic alterations in membrane ion channels (e.g. long QT sy ... Full text Cite

Splitting of the back edge of a propagating excitation pulse

Journal Article Biofizika · 1996 A new type of unstability of action potential propagating in spatially inhomogeneous electrically excitable media is announced. Numerical experiments with the FitzHugh-Nagumo model show that if the medium contains a region where membrane slow, outward curr ... Cite

[Splitting of the back edge of a propagating excitation pulse].

Journal Article Biofizika · January 1996 A new type of unstability of action potential propagating in spatially inhomogeneous electrically excitable media is announced. Numerical experiments with the FitzHugh-Nagumo model show that if the medium contains a region where membrane slow, outward curr ... Cite

Conditions for wavefront separation from an unexcitable obstacle in cardiac tissue of low excitability

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 1995 Wavelet formation following collision of a wavefront with an unexcitable obstacle is studied analytically and numerically in a two-dimensional FitzHugh Nagumo excitable medium. Conditions are found when the incident wave colliding with a thin unexcitable f ... Cite

Clock instability and its effect on time intervals in performance studies

Journal Article CMG Proceedings · December 1, 1995 Workstations in a local area network environment must provide a time service that is synchronized with the other clocks on the LAN. To stay synchronized, computers on a network exchange information about the time via a time service protocol and adjust thei ... Cite

Proarrhythmic response to potassium channel blockade. Numerical studies of polymorphic tachyarrhythmias.

Journal Article Circulation · August 1, 1995 Featured Publication BACKGROUND: Prompted by the results of CAST results, attention has shifted from class I agents that primarily block sodium channels to class III agents that primarily block potassium channels for pharmacological management of certain cardiac arrhythmias. R ... Full text Link to item Cite

CLOCK INSTABILITY AND ITS EFFECT ON TIME INTERVALS IN PERFORMANCE STUDIES

Conference 21st International Computer Measurement Group Conference, CMG 1995 · January 1, 1995 Workstations in a local area network environment must provide a time service that is synchronized with the other clocks on the LAN. To stay synchronized, computers on a network exchange information about the time via a time service protocol and adjust thei ... Cite

Numerical experiments in a modified Beeler-Reuter cable model: Initiating fast (Na) and slow (Ca) waves

Journal Article Chaos, Solitons and Fractals · January 1, 1995 We have modified the Beeler-Reuter model of cardiac muscle cells to account for the action of catecholamines. This model reveals the ability for slowly propagating calcium waves to coexist with the normal rapidly propagating wavefront associated with sodiu ... Full text Cite

Unexcitable zones as a source of spiral waves initiation and cardiac arrhythmias

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 1994 The initiation of a 2-D spiral wave rotation around a periodic lattice of unexcitable zones (obstacles) is studied numerically by the finite-difference method. The lattice consists of thin asymmetrical filaments formed by unexcitable (diseased) portions of ... Cite

Potassium channel blockade amplifies cardiac instability numerical studies of torsades de pointes.

Journal Article Indian journal of physiology and pharmacology · October 1994 Suppression of responses to premature stimulation has been the guiding principle in managing many cardiac arrhythmias. Recent clinical trails revealed that sodium channel blockade increased the incidence of re-entrant cardiac arrhythmias resulting in sudde ... Cite

Intellectual environment, technical resources and curiosity: elements for competitive research.

Journal Article Indian journal of physiology and pharmacology · October 1994 Cite

Vulnerability in excitable Belousov-Zhabotinsky medium: from 1D to 2D

Journal Article Physica D: Nonlinear Phenomena · September 15, 1994 Mechanisms for initiating rotating waves in 1D and 2D excitable media were compared and parameters affecting wavefront formation were analyzed. The time delay between two sequentially initiated wavefronts (a conditioning wave followed by a test wave) was v ... Full text Cite

Voltage-independent effects of extracellular K+ on the Na+ current and phase 0 of the action potential in isolated cardiac myocytes.

Journal Article Circ Res · September 1994 A rise in [K+]o, by depolarizing the resting membrane potential and partially inactivating the inward Na+ current (INa), is believed to play a critical role in slowing conduction during myocardial ischemia. In multicellular ventricular preparations, elevat ... Full text Link to item Cite

Late Na channels in cardiac cells: the physiological role of background Na channels.

Journal Article Biophys J · July 1994 Two types of the late Na channels, burst and background, were studied in Purkinje and ventricular cells. In the whole-cell configuration, steady-state Na currents were recorded at potentials (-70 to -80 mV) close to the normal cell resting potential. The q ... Full text Link to item Cite

Open Na+ channel blockade: multiple rest states revealed by channel interactions with disopyramide and quinidine.

Journal Article Am J Physiol · May 1994 In voltage-clamp studies of atrial myocytes exposed to disopyramide or quinidine, pulse-train stimulation revealed use-dependent block that increased with increased pulse amplitude. Use-dependent block also became negligible at hyperpolarized holding poten ... Full text Link to item Cite

Combination ethacizin and ethmozin treatment of resistant ventricular ectopy: theoretical, experimental, and clinical study.

Journal Article Journal of cardiovascular pharmacology · March 1994 Ethmozin (Moricizine HCl) and ethacizin are two class I antiarrhythmic drugs with different rate constants of interaction with the sodium channel. Computer simulation using the "guarded-receptor" model predicted that the combination of ethacizin and ethmoz ... Cite

Vulnerability in one-dimensional excitable media

Journal Article Physica D: Nonlinear Phenomena · February 15, 1994 Potentially life-threatening cardiac arrhythmias can be iniated with stimuli timed to occur during the "vulnerable window (VW)". We defined VW as the time interval between the "conditioning" and "test" stimuli following in sequence, during which the test s ... Full text Cite

Vulnerability in an excitable medium: analytical and numerical studies of initiating unidirectional propagation.

Journal Article Biophysical journal · November 1993 Featured Publication Cardiac tissue can display unusual responses to certain stimulation protocols. In the wake of a conditioning wave of excitation, spiral waves can be initiated by applying stimuli timed to occur during a period of vulnerability (VP). Although vulnerability ... Full text Cite

Kinetics of interaction of disopyramide with the cardiac sodium channel: fast dissociation from open channels at normal rest potentials.

Journal Article J Membr Biol · November 1993 Block of cardiac sodium channels is enhanced by repetitive depolarization. It is not clear whether the changes in drug binding result from a change in affinity that is dependent on voltage or on the actual state of the channel. This question was examined i ... Full text Link to item Cite

pH dependence of kinetics and steady-state block of cardiac sodium channels by lidocaine.

Journal Article Am J Physiol · May 1993 The local anesthetic-class antiarrhythmic drugs produce greater depression of conduction in ischemic compared with normal myocardium. The basis for this relatively selective action is uncertain. A model of the pH-dependent interaction of tertiary amine dru ... Full text Link to item Cite

Cellular Vmax reflects both membrane properties and the load presented by adjoining cells.

Journal Article The American journal of physiology · December 1992 This study was designed to test the hypothesis that the electrical load seen at a microelectrode impalement site is sensitive to the direction of propagation of the approaching wavefront as a reflection of an altered spatial relationship between the impale ... Full text Cite

Na channel kinetics remain stable during perforated-patch recordings.

Journal Article Am J Physiol · December 1992 The results of studies on modulation of Na channel function are often difficult to interpret due to time-dependent changes in channel kinetics. Although the "tight-seal" whole cell voltage-clamp technique has proved very useful in studying the properties o ... Full text Link to item Cite

Blockade of cardiac sodium channels. Competition between the permeant ion and antiarrhythmic drugs.

Journal Article J Clin Invest · August 1992 A number of basic and clinical studies suggest that elevation of external sodium concentrations, [Na]o, may reverse the cardiotoxic effect of local anesthetic-class drugs. The mechanisms of reversal are uncertain. The blocking action of lidocaine and disop ... Full text Link to item Cite

Kinetics of interaction of the lidocaine metabolite glycylxylidide with the cardiac sodium channel. Additive blockade with lidocaine.

Journal Article Circ Res · June 1992 The recovery of the sodium channel from blockade by local anesthetic antiarrhythmic drugs is voltage dependent. Recovery from lidocaine-induced blockade is accelerated by hyperpolarization, whereas that from glycylxylidide (GX) blockade has been reported t ... Full text Link to item Cite

A proarrhythmic response to sodium channel blockade: modulation of the vulnerable period in guinea pig ventricular myocardium.

Journal Article Journal of cardiovascular pharmacology · May 1992 The vulnerable period (VP) is an interval of time during the cardiac cycle within which premature stimulation may lead to trains of responses (one: many stimulus-response coupling). Although the VP parallels the recovery of sodium channel availability, mod ... Cite

Cardiac instability amplified by use-dependent Na channel blockade.

Journal Article Am J Physiol · April 1992 Featured Publication Drugs that exhibit use-dependent Na channel blockade, including antiarrhythmic agents, tricyclic antidepressants, opiate-like analgesics, and cocaine, are linked with an increased susceptibility to cardiac arrhythmias and sudden death. Computer simulations ... Full text Link to item Cite

Frequency-dependent processes: a model for short-term memory

Journal Article Journal of Statistical Planning and Inference · January 1, 1992 Many biological respomses are dependent on the frequency of excitation. Frequency-dependent processes are a class of ligand binding processes where the degree of binding site saturation may be dependent on the cumulative duration of ligand release or recep ... Full text Cite

A source of bias in the analysis of single channel data: assessing the apparent interaction between channel proteins.

Journal Article Comput Biomed Res · December 1991 A recent study of single sodium channel currents in neuroblastoma cells suggested interaction between ion channels in close proximity to one another (T. Kiss and K. Nagy, Eur. Biophys. J. 12, 13, 1985). The opening of one channel appeared to affect the lik ... Full text Link to item Cite

Steady state variables in the guarded receptor hypothesis.

Journal Article The American journal of physiology · December 1991 Full text Cite

Blockade of cardiac sodium channels by amitriptyline and diphenylhydantoin. Evidence for two use-dependent binding sites.

Journal Article Circ Res · September 1991 Cardiac toxicity is a frequent manifestation in amitriptyline overdose and is felt to be due, in part, to sodium channel blockade by the drug. Another agent with sodium channel blocking properties, diphenylhydantoin, has been used clinically to reverse car ... Full text Link to item Cite

Proarrhythmic response to sodium channel blockade. Theoretical model and numerical experiments.

Journal Article Circulation · September 1991 Featured Publication BACKGROUND: The use of flecainide and encainide was terminated in the Cardiac Arrhythmia Suppression Trial because of an excess of sudden cardiac deaths in the active treatment group. Such events might arise from reentrant rhythms initiated by premature st ... Full text Link to item Cite

The quantitative investigation of the binding process of calcium blocking drugs in a sinoatrial node.

Journal Article Journal of theoretical biology · March 1991 Application of existing models of sinoatrial node pacemaker activity and of channel-drug interaction allow us to reproduce action potential changes as a result of the blocking effect of drugs. Two calcium antagonistic drugs, nifedipine and mesudipine, were ... Full text Cite

Modulating intraventricular conduction through competition of two class 1 antiarrhythmic agents: experience with ethacizin and lidocaine in canine heart.

Journal Article Journal of molecular and cellular cardiology · February 1991 The frequency-dependent effects on the intraventricular conduction through the dog heart in situ produced by two class 1 antiarrhythmic drugs, ethacizin and lidocaine, with different kinetic properties were investigated. Conduction delay was measured using ... Full text Cite

Lidocaine blockade of continuously and transiently accessible sites in cardiac sodium channels.

Journal Article J Mol Cell Cardiol · February 1991 Lidocaine binds to sodium channels in a voltage dependent manner where depolarization enhances block and hyperpolarization relieves block. Voltage--clamp studies demonstrate that there are two components of block: one involving interaction with a binding s ... Full text Link to item Cite

Channel specificity in antiarrhythmic drug action. Mechanism of potassium channel block and its role in suppressing and aggravating cardiac arrhythmias.

Journal Article Circulation · December 1990 Featured Publication Although work on class III antiarrhythmics remains at an early stage, these agents still appear to possess greater efficacy and less proarrhythmia than conventional class I agents in those experimental arrhythmia models considered to be most representative ... Full text Cite

Visualization tools for biomedical research

Journal Article Proceedings of the First Conference on Visualization in Biomedical Computing · December 1, 1990 A system of graphical software tools to facilitate the two-dimensional visualization of primary and model data is described. The system uses a direct manipulation interface developed at Duke University Medical Center. This system presents the investigator ... Cite

Quinidine blocks adenosine 5'-triphosphate-sensitive potassium channels in heart.

Journal Article The American journal of physiology · November 1990 The ATP-sensitive potassium channel current (IK-ATP) was studied in excised inside-out patches from rat ventricular cells at 20-23 degrees C. The bath solution contained 140 mM KF, and the pipette solution contained 140 mM KCl and 1.2 mM MgCl2. ATP (0.5 mM ... Full text Cite

Extracellular pH modulates block of both sodium and calcium channels by nicardipine.

Journal Article Am J Physiol · October 1990 Slowing of the recovery of the Na channel from local anesthetic block at low external pH has been well described. In contrast the Ca channel has been reported not to show such an effect. Because of the absence of this response, a two-site model for the int ... Full text Link to item Cite

Use of ionic currents to identify and estimate parameters in models of channel blockade.

Journal Article Am J Physiol · August 1990 Models of ion channel blockade are frequently validated with observations of ionic currents resulting from electrical or chemical stimulation. Model parameters for some models (modulated receptor hypothesis) cannot be uniquely determined from ionic current ... Full text Link to item Cite

Managing clinical research data: software tools for hypothesis exploration.

Journal Article Environmental health perspectives · July 1990 Data representation, data file specification, and the communication of data between software systems are playing increasingly important roles in clinical data management. This paper describes the concept of a self-documenting file that contains annotations ... Full text Cite

State dependence of ethacizin and ethmozin block of sodium current in voltage clamped and internally perfused cardiac Purkinje cells.

Journal Article The Journal of pharmacology and experimental therapeutics · June 1990 Ethacizin, a positively charged analog of ethmozin, reduces the cardiac action potential upstroke and blocks peak sodium current (INa). We investigated ethacizin block of INa in 11 cells and ethmozin block in 4 cells at 20 degrees C. Rest block measured as ... Cite

[The combined effect of 2 first-line anti-arrhythmia drugs on the conduction velocity of myocardial stimulation].

Journal Article Kardiologiia · March 1990 Experiments with recording the time of intraventricular reentry of the canine heart by a special protocol of stimulation showed that the first-line antiarrhythmic agents having various kinetics, ethacizine and lidocaine, compete for their binding to the Na ... Cite

The combined effect of 2 first-line anti-arrhythmia drugs on the conduction velocity of myocardial stimulation

Journal Article Kardiologiya · March 1, 1990 Experiments with recording the time of intraventricular reentry of the canine heart by a special protocol of stimulation showed that the first-line antiarrhythmic agents having various kinetics, ethacizine and lidocaine, compete for their binding to the Na ... Cite

An object oriented user interface for analysis of biological data.

Journal Article Comput Biomed Res · February 1990 In a previous paper we described a self-documented file and a collection of general purpose programs or tools that facilitates the management and analysis of biological data. The tools can be specified in a pipeline to accomplish a specific analysis task. ... Full text Link to item Cite

The combined effect of 2 first-line anti-arrhythmia drugs on the conduction velocity of myocardial stimulation

Journal Article Kardiologiya · 1990 Experiments with recording the time of intraventricular reentry of the canine heart by a special protocol of stimulation showed that the first-line antiarrhythmic agents having various kinetics, ethacizine and lidocaine, compete for their binding to the Na ... Cite

Ethacizin blockade of calcium channels: A test of the guarded receptor hypothesis

Journal Article American Journal of Physiology - Heart and Circulatory Physiology · December 14, 1989 The effect on calcium channels of the sodium channel antagonist, ethacizin, was studied in isolated frog ventricular cells using the whole cell voltage-clamp methodology. Ethacizin was found to block inward calcium current in a frequency-, voltage-, and co ... Cite

Characterization of the surface topography and putative tertiary structure of the human CD7 molecule.

Journal Article J Immunol · December 1, 1989 The CD7 gp40 molecule is a member of the Ig gene superfamily and is expressed on T cell precursors before their entry into the thymus during fetal development. N-terminal amino acids 1-107 of CD7 are highly homologous to Ig kappa-L chains whereas the carbo ... Link to item Cite

Marked QRS complex abnormalities and sodium channel blockade by propoxyphene reversed with lidocaine.

Journal Article J Clin Invest · November 1989 The opiate analgesic propoxyphene produces cardiac toxicity when taken in overdose. We recently observed a patient with propoxyphene overdose in whom marked QRS widening was reversed by lidocaine. The reversal is apparently paradoxical as both agents block ... Full text Link to item Cite

Ethacizin blockade of calcium channels: a test of the guarded receptor hypothesis.

Journal Article The American journal of physiology · November 1989 The effect on calcium channels of the sodium channel antagonist, ethacizin, was studied in isolated frog ventricular cells using the whole cell voltage-clamp methodology. Ethacizin was found to block inward calcium current in a frequency-, voltage-, and co ... Full text Cite

Blockade of cardiac sodium channels by lidocaine. Single-channel analysis.

Journal Article Circ Res · November 1989 The mechanism of interaction of lidocaine with cardiac sodium channels during use-dependent block is not well defined. We examined the blockade of single cardiac sodium channels by lidocaine and its hydrophobic derivative RAD-242 in rabbit ventricular myoc ... Full text Link to item Cite

Blockade of rabbit atrial sodium channels by lidocaine. Characterization of continuous and frequency-dependent blocking.

Journal Article Circ Res · September 1989 Featured Publication Lidocaine block of the cardiac sodium channel is believed to be primarily a function of channel state. For subthreshold potentials, block is limited to the inactivated state, whereas above threshold, block results from the combination of open- and inactiva ... Full text Link to item Cite

Characterization of concentration- and use-dependent effects of quinidine from conduction delay and declining conduction velocity in canine Purkinje fibers.

Journal Article J Clin Invest · June 1989 The dynamic response of squared conduction velocity, theta 2, to repetitive stimulation in canine Purkinje fibers with quinidine was studied using a double-microelectrode technique. With stimulation, a frequency-dependent monoexponential increase in conduc ... Full text Link to item Cite

Characterizing activity-dependent processes with a piecewise exponential model

Journal Article Mathematical and Computer Modelling · January 1, 1989 The response of some biological processes is dependent on the frequency of stimulation. With first-order processes, the response is driven exponentially to an equilibrium determined by the value of the driving function. When the stimulus or driving functio ... Full text Cite

POET: A tool for the analysis of the performance of parallel algorithms

Journal Article Proceedings of the International Conference on Parallel Processing · December 1, 1988 The tool consists of a simple language for describing algorithms and an interpreter that determines the execution time on a given number of processors. The key concept is the separate specification of local computation and remote memory access in the algor ... Cite

Characterizing activity-dependent processes with a piecewise exponential model.

Journal Article Biometrics · June 1988 Featured Publication The response of some biological processes is dependent on the frequency of stimulation. With first-order processes, the response is driven exponentially to an equilibrium determined by the value of the driving function. When the stimulus or driving functio ... Full text Cite

CHARACTERIZING SYNAPTIC PLASTICITY WITH AN ACTIVITY DEPENDENT MODEL.

Journal Article · December 1, 1987 Recent studies of the interactions between pharmacologic agents and ion channels in excitable membrane have yielded an analytical characterization of use- or activity-dependent processes. Using this model and observations of habituation and sensitization i ... Cite

Theoretical characterization of ion channel blockade. Competitive binding to periodically accessible receptors.

Journal Article Biophysical journal · September 1987 Competitive ligand binding to periodically activated or accessible receptors is influenced by the interaction between ligand binding kinetics and the interval of time the binding site is accessible. This interaction produces a paradoxical reduction in boun ... Full text Cite

Mechanisms of closure of cardiac sodium channels in rabbit ventricular myocytes: single-channel analysis.

Journal Article Circ Res · June 1987 We have examined the kinetics of closure of sodium channels using single-channel recordings in cell-attached and excised membrane patches of rabbit ventricular myocytes. Sodium-channel closure was dependent on membrane potential. The closing rate initially ... Full text Link to item Cite

Managing research data with self-documenting files.

Journal Article Computers and biomedical research, an international journal · June 1987 Processing biomedical research data is frequently complex due to the evolutionary nature of experiments and the requisite modification of analysis software. For the past several years we have been evolving a set of software tools designed to improve our ab ... Full text Cite

Ligand binding to transiently accessible sites: mechanisms for varying apparent binding rates.

Journal Article J Theor Biol · February 7, 1987 Many biological processes are characterized by models where ligand has continuous access to binding sites. Use-dependent processes such as ion channel blockade appear to represent a class of processes where binding site access is transient and is dependent ... Full text Link to item Cite

Modeling ion channel blockade at guarded binding sites: application to tertiary drugs.

Journal Article The American journal of physiology · October 1986 Excitable membranes exposed to sodium channel blocking agents (D; local anesthetics and antiarrhythmic drugs) show a progressive reduction of peak sodium current when repetitively depolarized (use dependence). Thus, with repetitive excitation, use dependen ... Full text Cite

pKa does not predict pH potentiation of sodium channel blockade by lidocaine and W6211 in guinea pig ventricular myocardium.

Journal Article The Journal of pharmacology and experimental therapeutics · July 1986 During diastole, tertiary amine local anesthetic molecules may exit cardiac sodium channels quickly through the membrane if they are neutral, or more slowly through the aqueous channel pore if they are charged. Extracellular acidosis potentiates sodium cha ... Cite

A quantitative description of QX222 blockade of sodium channels in squid axons.

Journal Article Biophysical journal · April 1986 The interaction of QX222, a quaternary ammonium derivative of lidocaine, with the Na channel was studied in internally perfused squid axons under voltage-clamped conditions. A use-dependent block was observed in response to repetitive depolarizing pulses. ... Full text Cite

Theoretical characterization of ion channel blockade: ligand binding to periodically accessible receptors.

Journal Article Journal of theoretical biology · March 1986 With repetitive stimulation, the time course of use-dependent blockade as assessed by peak membrane ion currents can be described by a sequence of blocking relationships that have the form of recurrence equations. The equations of the sequence describe blo ... Full text Cite

Phasic ion channel blockade. A kinetic model and parameter estimation procedure.

Journal Article Mol Pharmacol · October 1985 Featured Publication For excitable membranes, use and frequency dependence represent a progressive incorporation of drug into gated ion channels with repetitive stimulation. In contrast to receptors where access to ligand is continuous in time, we define guarded receptors, suc ... Link to item Cite

Simulation of use-dependent uptake of ion channel blocking agents by excitable membranes.

Journal Article IEEE transactions on bio-medical engineering · October 1985 Full text Cite

Mechanisms of apparent affinity variation of guarded receptors.

Journal Article Journal of theoretical biology · August 1985 Studies of interactions between blocking agents such as antiarrhythmic drugs and gated ion channels have suggested apparent variations in binding site affinity. In this report, we develop a model by which these properties of ion channels can be explained s ... Full text Cite

Lipid solubility modulates pH potentiation of local anesthetic block of Vmax reactivation in guinea pig myocardium.

Journal Article Circ Res · October 1984 Current theories envision recovery from local anesthetic block of sodium channels via slow hydrophilic and fast hydrophobic paths. Extracellular pH reduction which increases cationic/neutral anesthetic form should especially prolong recovery kinetics of hi ... Full text Link to item Cite

Spurious hypertension in the obese patient. Effect of sphygmomanometer cuff size on prevalence of hypertension.

Journal Article Arch Intern Med · July 1984 We used standard, large adult, and thigh-size cuffs in random order to take BPs in 470 patients. The prevalences of definite high BP [( HBP]), greater than or equal to 160/95 mm Hg) and borderline HBP [( BHBP ], greater than or equal to 140/90 less than 16 ... Link to item Cite

Mechanisms of use-dependent block of sodium channels in excitable membranes by local anesthetics.

Journal Article Biophys J · July 1984 Many local anesthetics promote reduction in sodium current during repetitive stimulation of excitable membranes. Use-, frequency-, and voltage-dependent responses describe patterns of peak INa when pulse width, pulse frequency, and pulse amplitude are vari ... Full text Link to item Cite

FEEDBACK STABILIZATION OF CONTROL POLICY SELECTION IN DATA/KNOWLEDGE BASED SYSTEMS.

Conference Proceedings - International Conference on Data Engineering · January 1, 1984 Knowledge and/or data-based decision support systems can be viewed as complex control systems designed to optimize a desired criterion. As such. they aid users in transforming objects with an initial state vector to some desired outcome state by applicatio ... Cite

A method for quantitating antifibrillatory effects of drugs after coronary reperfusion in dogs: improved outcome with bretylium.

Journal Article Circulation · January 1984 We developed a quantitative approach to assess the antifibrillatory effects of short-term interventions in a canine preparation of ventricular fibrillation caused by coronary reperfusion, and applied it to evaluate the antifibrillatory effects of bretylium ... Full text Cite

Unitary sodium channels in isolated cardiac myocytes of rabbit.

Journal Article Circ Res · December 1983 Featured Publication Transmembrane ionic movements are thought to occur through special membrane areas or channels. Until recently, it has not been possible to study the properties of individual ionic channels, directly. We have used the extracellular patch clamp technique to ... Full text Link to item Cite

BP control. Improvement in a university medical clinic by use of a physician's associate.

Journal Article Arch Intern Med · May 1983 Many hypertensive patients, especially those in outpatient clinics at large teaching hospitals, do not achieve BP control. We incorporated a physician's associate into an existing house staff medical clinic and evaluated whether this improved BP control. I ... Full text Link to item Cite

Optimizing Contiguous-Element Region Selection for Virtual Memory Systems

Journal Article IEEE Transactions on Computers · January 1, 1983 Contiguous element region selection is a fundamental step in many image analysis applications. This application is often run on computers with virtual memory systems. The page fault behavior of the contiguous element selection algorithm is greatly influenc ... Full text Cite

ANALYSIS OF SPECT USING MONTE CARLO SIMULATION.

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 1982 Cite

Error sensitivity of computerized tomography guided stereotaxis.

Journal Article Computers and biomedical research, an international journal · June 1982 Full text Cite

A data-based approach to assessing clinical interventions in the setting of chronic disease.

Journal Article Cancer Treat Rep · May 1982 Accurately assessing the effect of a clinical intervention is a complex task based on observing patients and their outcomes. Two strategies, the randomized trial and the observational data bank, represent different approaches toward detecting an outcome gr ... Link to item Cite

A simulation-based sensitivity study of radionuclide angiocardiographic approaches to shunt assessment.

Journal Article Computers and biomedical research, an international journal · April 1982 Full text Cite

A recursively interpreted data structure for representing clinical entities.

Journal Article Journal of medical systems · April 1982 Clinical investigations generate a spectrum of data and data relationships that no longer fit simple data structures. To build a data management facility sufficiently flexible to deal with this spectrum of structures is thus an important problem. A general ... Full text Cite

Analysis of spect including scatter and attenuation using sophisticated monte carlo modeling methods

Journal Article IEEE Transactions on Nuclear Science · January 1, 1982 The effects of scatter and attenuation on single photon emission computed tomography (SPECT) images can be analyzed with the aid of sophisticated Monte Carlo simulation. Correction procedures can be evaluated by comparing corrected images with images absen ... Full text Cite

PROBLEMS IN DATA MANAGEMENT WHEN STUDYING CHRONIC ILLNESS.

Journal Article Proceedings of the Hawaii International Conference on System Science · December 1, 1981 Cite

Computed tomography brain scanning in alcohol withdrawal seizures. Value of the neurologic examination.

Journal Article Annals of internal medicine · April 1981 We evaluated the usefulness of computed tomography (CT) brain scanning in alcoholic patients with withdrawal seizures (n = 151) and other neurologic problems (n = 87) and compared the findings of a detailed neurologic examination to the results of CT scann ... Full text Cite

ANALYSIS OF SPECT INCLUDING SCATTER AND ATTENUATION USING SOPHISTICATED MONTE CARLO MODELING METHODS.

Journal Article IEEE Transactions on Nuclear Science · 1981 A Monte Carlo-based computer program accurately simulates the SPECT imaging system response. The performance of the simulation is illustrated and system resolution, effects of scatter and attenuation, and the final image variance are shown to be comparable ... Cite

Problems in data management when studying chronic illness.

Journal Article Journal of medical systems · 1981 Chronic illness is characterized by a long response time during which many external influences can modify the system. Accurate characterization of such a system may require a large number of attributes. Such "data" complexity, in both the time and the feat ... Cite

On the complexity of investigating chronic illness.

Journal Article Biometrics · June 1980 Chronic diseases are in many ways more complex than acute diseases. In chronic diseases, response times to environmental effects are long, and confounding variables are numerous and may fluctuate with time. Treatment schedules are complicated and may be un ... Link to item Cite

Clinical judgment and statistics. Lessons from a simulated randomized trial in coronary artery disease.

Journal Article Circulation · March 1980 A simulated randomized clinical trial in coronary artery disease was conducted to illustrate the need for clinical judgment and modern statistical methods in assessing therapeutic claims in studies of complex diseases. Clinicians should be aware of problem ... Full text Link to item Cite

DATABASE APPROACH FOR STABILIZING CLINICAL DECISIONS IN THE SETTING OF CHRONIC ILLNESS.

Journal Article Institution of Mechanical Engineers, Conference Publications · January 1, 1979 Stabilizing clinical decisions can be aided by incorporating outcome data into treatment decisions. Feedback of outcome data can be managed manually for acute illnesses. When the time between intervention and outcome becomes long as in chronic disease, the ... Cite

Error propagation in quantitative biplane cineroentgenography.

Journal Article Physics in medicine and biology · July 1978 The propagation of errors in quantitative biplane cineroentgenography was investigated to see which variables were the most critical. The analysis was carried out both for the propagation of root-mean-square errors and for errors as derived by a Taylor exp ... Full text Cite

Laboratory for development of health information system

Journal Article Abstracts of Hospital Management Studies · January 1, 1978 The objective of the research is to establish a data bank consisting of clinical data from patients with coronary artery disease. This extensive, longitudinal and reliable collection of data represents an aggregated clinical experience that can be shared w ... Cite

Synaptonemal complex karyotyping in spermatocytes of the Chinese hamster (Cricetulus griseus). III. Quantitative evaluation.

Journal Article Chromosoma · April 1977 Relative length is a constant and distinctive characteristic for each autosomal SC, despite variations in absolute length from cell to cell. Arm ratio is distinctive for each SC except for two of the three sub-acrocentrics, and serves, together with relati ... Cite

The relationship between enzymatic and histologic estimates of the extent of myocardial infarction in conscious dogs with permanent coronary occlusion.

Journal Article Circulation · March 1977 Relationships between enzyme estimates (EE) and histologic measurements of infarct size (HIS) were analyzed in 14 conscious dogs with permanent occlusion of the circumflex coronary artery. EE were derived from serial CPK, CPK-MM, CPK-MB, and CPK-BB. Estima ... Full text Cite

A DSS for management of patients with a chronic illness

Journal Article ACM SIGMIS Database · January 1, 1977 There is uncertainty in the management of an individual with a chronic illness. The uncertainty results from lack of information about groups of similar patients. A feedback model for patient care is presented and its implementation discussed. The model re ... Full text Cite

Computer representation of coronary arterial trees.

Journal Article Computers and biomedical research, an international journal · April 1976 Full text Cite

Sudden death due to coronary artery disease. A clinical, hemodynamic, and angiographic profile.

Journal Article Circulation · December 1975 The authors followed 536 medically managed patients with angiographically documented coronary artery disease for up to 4 years, and examined antemortem clinical, anatomical, and hemodynamic characteristics of the 29 patients who died suddenly during the fo ... Link to item Cite

A new information system for medical practice.

Journal Article Archives of internal medicine · August 1975 Featured Publication A data bank containing our clinical experience with more than 3,000 patients with suspected and documented ischemic heart disease is being used to expand our ability to care for patients. This report describes how the experience is documented, stored, and ... Full text Cite

The course of acute myocardial infarction. Feasibility of early discharge of the uncomplicated patient.

Journal Article Circulation · March 1975 This report represents our experience with 522 consecutive patients with acute myocardial infarction admitted directly to the Duke Coronary Care Unit. Fifty items of information were used to characterize the patients, their hospital course and follow-up. S ... Full text Cite

Problems in Acquisition and Representation of Coronary Arterial Trees

Journal Article Computer · January 1, 1975 The nature of the contractions of the heart wall has long been recognized as indicative of the presence and degree of atherosclerotic lesions in the coronary arteries. More recently, the coronary arterial tree-itself has been studied and the changes in len ... Full text Cite

Computer storage and retrieval of coronary trees

Journal Article PROC.SOC.PHOTO-OPT.INSTR.ENGIN. · January 1, 1975 This paper describes a collection of simple ideas and procedures to aid in the collection and analysis of coronary arterial trees. The uses to which the tree data will be put include the evaluation of myocardial function and the formation of a library suff ... Cite

COMPUTER STORAGE AND RETRIEVAL OF CORONARY TREES.

Journal Article SPIE Semin Proc · January 1, 1975 Coronary cineangiography is a routine procedure in the authors' hospital for evaluation of the coronary circulation. From the biplane cineangiograms one obtains a visual representation of coronary perfusion. In addition the three-dimensional structure of t ... Cite

A kinetic model for the intramolecular distribution of 15N in uric acid in patients with primary gout fed 15N-glycine

Journal Article Mathematical Biosciences · January 1, 1975 The concept of an abnormality of glutamine metabolism in primary gout was first proposed on the basis of isotope data: when 15N-glycine was administered to gouty subjects, there was disproportionately great enrichment of N-(3+9) of uric acid, which derive ... Full text Cite

Computer-based aid to managing patients with illness chronic

Journal Article Computer · January 1, 1975 The ability of the computer-based data bank to provide a quality of information about like patients that is not available in textbooks, journals, and monographs creates a degree of excitement and timeliness in the long-term management of chronically ill pa ... Full text Cite

A comparison of frequency distributions for use in a model for selecting treatment in coronary artery disease.

Journal Article Computers and biomedical research, an international journal · June 1974 Cite

Editorial: Data bank use in management of chronic disease.

Journal Article Computers and biomedical research, an international journal · April 1974 Full text Cite

Comment

Journal Article Journal of the American Statistical Association · January 1, 1974 Full text Cite

PROBLEMS IN ACQUISITION AND REPRESENTATION OF CORONARY ARTERIAL TRESS.

Journal Article · January 1, 1974 The nature of the contractions of the heart wall has long been recognized as indicative of the presence and degree of atherosclerotic lesions in the coronary arteries. More recently, the coronary arterial tree itself has been studied and the changes in len ... Cite

The kinetics of intramolecular distribution of 15N in uric acid after administration of (15N) glycine. A reappraisal of the significance of preferential labeling of N-(3+9) of uric acid in primary gout.

Journal Article The Journal of clinical investigation · October 1973 Featured Publication THE CONCEPT OF AN ABNORMALITY OF GLUTAMINE METABOLISM IN PRIMARY GOUT WAS FIRST PROPOSED ON THE BASIS OF ISOTOPE DATA: when [(15)N]glycine was administered to gouty subjects, there was disproportionately great enrichment of N-(3 + 9) of uric acid, which de ... Full text Cite

Current density and electrically induced ventricular fibrillation.

Journal Article Medical instrumentation · March 1973 Featured Publication Cite

Processing of arterial pressure waves with a digital computer.

Journal Article Computers and biomedical research, an international journal · February 1973 Full text Cite

Current density and electrically induced ventricular fibrillation.

Journal Article Medical instrumentation · January 1973 Cite

A reappraisal of the concept of an abnormality of glutamine metabolism in primary gout.

Journal Article Transactions of the American Clinical and Climatological Association · January 1973 Cite

A nonparametric general linear model.

Journal Article Computers and biomedical research, an international journal · December 1972 Full text Cite

Interactive acquisition and analysis of discrete data.

Journal Article Computers and biomedical research, an international journal · October 1972 Cite

Fibrillatory current thresholds & standards.

Journal Article Health devices · June 1972 Cite

Measurement of aortic blood flow in man by the computed pressure derivative method.

Journal Article Journal of applied physiology · November 1971 Full text Cite

SAN DIEGO BIOMEDICAL SYMPOSIUM, 1971, PROCEEDINGS, v 10.

Journal Article · January 1, 1971 Following is a continuation of the listing of papers presented: Automatic Calibration of On-Line Respiratory Measurements. By J. O. Beaumont and W. A. Radke. System for Storage and Retrieval of Textual and Numeric Data Collected During Patient Monitoring. ... Cite

Electrical hazards and cardiovascular function.

Journal Article The New England journal of medicine · January 1971 Full text Cite

Hemodynamic findings in 123 patients with acute myocardial infarction on admission.

Journal Article Circulation · October 1970 Hemodynamic and clinical evaluations of 123 patients with acute myocardial infarction were performed during the first hour of admission to the hospital. In the 123 patients, the right atrial pressure was less than 10 mm Hg in 49 patients, the right atrial ... Full text Cite

Computer computations of cardiac output using the gamma function.

Journal Article Journal of applied physiology · February 1970 Featured Publication Full text Cite

Analysis of categorical data by linear models.

Journal Article Biometrics · September 1969 Featured Publication Full text Cite

Pressure-flow studies in man. An evaluation of the duration of the phases of systole.

Journal Article The Journal of clinical investigation · May 1969 Featured Publication This study was designed to assess the independent effects of stroke volume and heart rate on the phases of systole and other selected hemodynamic parameters. By means of the pressure gradient technique instantaneous blood pressure and flow were recorded in ... Full text Cite

Electric shock hazards in clinical cardiology.

Journal Article Modern concepts of cardiovascular disease · February 1967 Cite

Determination of leakage currents in medical equipment.

Journal Article The American journal of cardiology · March 1966 Featured Publication Full text Cite

Electric shock hazards in radiology departments.

Journal Article The American journal of roentgenology, radium therapy, and nuclear medicine · December 1965 Full text Cite

Letter to the Editor: on the electrocardiographic field equation.

Journal Article The Bulletin of mathematical biophysics · December 1965 Full text Cite

HAZARDS OF ELECTRIC SHOCK IN CARDIOLOGY.

Journal Article The American journal of cardiology · October 1964 Featured Publication Full text Cite

ELECTRICAL HAZARDS ASSOCIATED WITH CARDIAC PACEMAKING.

Journal Article Annals of the New York Academy of Sciences · June 1964 Full text Cite

INDICATOR TRANSIT TIME CONSIDERED AS A GAMMA VARIATE.

Journal Article Circulation research · June 1964 Featured Publication Full text Cite