A5080820249- Cardiac electrophysiology and arrhythmias
- Heart Rate Variability and Autonomic Control
- Ion channel regulation and function
- ECG Monitoring and Analysis
- Neonatal Respiratory Health Research
- Non-Invasive Vital Sign Monitoring
- Neural dynamics and brain function
- EEG and Brain-Computer Interfaces
- Neuroscience and Neural Engineering
- Spaceflight effects on biology
- Cardiovascular Syncope and Autonomic Disorders
- Neuroscience of respiration and sleep
- Neuroscience and Music Perception
- Cardiovascular and exercise physiology
- Toxoplasma gondii Research Studies
- Cardiovascular Effects of Exercise
- Neonatal and fetal brain pathology
- Air Quality and Health Impacts
- Infant Development and Preterm Care
- High Altitude and Hypoxia
- Respiratory Support and Mechanisms
- Cardiac Arrest and Resuscitation
- Cardiomyopathy and Myosin Studies
- Music Therapy and Health
- Climate Change and Health Impacts
University of Kentucky
2015-2024
Rhythm (United states)
2019
Texas Cardiac Arrhythmia
2011
Southlake Regional Health Center
2011
Massachusetts General Hospital
2011
Harvard University
2011
National Heart Centre Singapore
2011
St David's Medical Center
2011
United States Department of Veterans Affairs
2011
James Cook University Hospital
2006
Despite their critical role in chronic toxoplasmosis, the biology of Toxoplasma gondii bradyzoites is poorly understood. In an attempt to address this gap, we optimized approaches purify tissue cysts and analyzed replicative potential within these cysts. order quantify individual cysts, have developed imaging software, BradyCount 1.0, that allows rapid establishment bradyzoite burdens imaged optical sections purified While general larger contain more bradyzoites, relative "occupancy" was...
The autonomic nervous system drives variability in heart rate, vascular tone, cardiac ejection, and arterial pressure, but gender differences regulation of the latter three parameters are not well documented. In addition to mean values, we used spectral analysis calculate rate (R-R interval, RRI), stroke volume, total peripheral resistance (TPR) measured circulating levels catecholamines pancreatic polypeptide two groups 25 ± 1.2-yr-old, healthy men follicular-phase women (40 subjects, 10...
The molecular clock mechanism underlies circadian rhythms and is defined by a transcription-translation feedback loop. Bmal1 encodes core transcription factor. Germline knockout mice show loss of variation in heart rate blood pressure, they develop dilated cardiomyopathy. We tested the role adult cardiomyocytes generating that allow for inducible cardiomyocyte-specific deletion (iCSΔBmal1). ECG telemetry showed (iCSΔBmal1(-/-)) slowed rate, prolonged RR QRS intervals, increased episodes...
Interactions of sympathetic nerve activity (SNA) with blood pressure (BP) and heart rate (HR) were assessed in conscious rats while they rested quietly a cloth sock (n = 7), roamed freely their home cage 6), then after anesthesia pentobarbital (30 mg/kg; n 7). The power coherence spectra below 3 Hz calculated from data collected for 9.56 min. In the rat, SNA spectral peaked at 0.4 Hz, whereas majority both BP HR occurred frequencies lower than Hz. However, there was an inconspicuous peak...
Variations in respiratory pattern influence the heart rate spectrum. It has been suggested, hence, that metronomic respiration should be used to correctly assess vagal modulation of by using spectral analysis. On other hand, breathing a metronome reported increase power high- or frequency region; this finding led suggestion enhances tone alters rate. To investigate whether complicates interpretation spectra altering modulation, we recorded electrocardiogram and from eight volunteers during...
Restitution of action potential duration (APD) is thought to be critical in activation instability. Although restitution used predict APD during sequential changes diastolic interval (DI), currently protocols determine do not use DI. We explored using a new pacing protocol change DI sequentially and independently APD. Transmembrane potentials were recorded from right ventricular endocardial tissue isolated six dogs. three patterns DIs: oscillatory, demonstrate differences APDs depending on...
Hypertension is a major risk factor for developing cardiac hypertrophy and heart failure. Previous studies show that hypertrophied failing hearts display alterations in excitation-contraction (E-C) coupling. However, it unclear whether remodeling of the E-C coupling system occurs before or after disease development. We hypothesized hypertension might cause changes that, turn, induce hypertrophy. Here we tested this hypothesis by utilizing progressive development hypertensive spontaneously...
Investigation of relationship between diastolic-interval (DI)-dependent restitution action potential duration (APD) and alternans APD has produced conflicting results. We used a novel pacing protocol to determine the role in by minimizing changes DI preceding each activation.Transmembrane potentials were recorded from right ventricular endocardial tissue isolated five dogs. three sequences: (i) The was paced at constant for 100 beats. (ii) DIs changed randomly two sequences DI. (iii) Each...
The mitochondrion is intimately linked to energy and overall metabolism therefore the morphology of can be very informative for inferring metabolic state cells. In this study we report an approach automatic classification mitochondrial morphologies using supervised machine learning efficiently classify them from a large number cells at time. Fluorescence microscopy images chronic encysted form parasite Toxoplasma gondii were used development. Manually classifying these hundreds parasites...
We investigated the effects of voluntary control breathing on autonomic function in cardiovascular regulation. Variability heart rate was compared between 5 min spontaneous and controlled breathing. During breathing, for min, subjects voluntarily reproduced their own pattern (both volume a breath-by-breath basis). With use this experimental design, we could unmask override respiratory generator regulation without confounding altered pattern. Results from 10 showed that during mean values...
Cardiac electric therapies effectively terminate tachyarrhythmias. Recent data suggest a possible increase in long-term mortality associated with implantable cardioverter-defibrillator shocks. Little is known about the association between external cardioversion episodes (ECVe) and mortality. We sought to assess safety of repeated ECVe regard cardiovascular morbidity.We analyzed 4060 patients from AFFIRM (Atrial Fibrillation Follow-up Investigation Rhythm Management) trial. In particular,...
Long QT syndrome type 3 (LQT3) is caused by mutations in the SCN5A-encoded Nav1.5 channel. LQT3 patients exhibit time of day-associated abnormal increases their heart rate-corrected (QTc) intervals and risk for life-threatening episodes. This study determines effects uncoupling environmental cues that entrain circadian rhythms (time light feeding) on rate ventricular repolarization wild-type (WT) or transgenic mice (Scn5a(+/ΔKPQ)). We used an established phase-restricted feeding paradigm...
In utero exposure to opiates may affect autonomic functioning of the fetus and newborn. We investigated heart rate variability (HRV) as a measure stability in prenatal opiate exposed neonates (n=14) control term infants (n=10). Electrocardiographic data during both non-nutritive nutritive sucking were evaluated for RR intervals, (HR), standard deviation intervals (SDRR), differences subsequent (SDDRR), power spectral densities low high frequency bands. controls, mean HR increased...
Intermittent hypoxaemia (IH) events are well described in extremely preterm infants, but the occurrence of IH patterns more mature infants remains unclear. The objective this study was to characterise effect gestational age on early postnatal (<28 weeks), very (28–<32 weeks) and moderately (32–<34 infants. As expected, had a significantly higher frequency longer durations greater time with versus In addition, decrease duration comparable This progression should assist clinicians...
In 28 healthy adults, we compared the dynamic interaction between respiration and cerebral autoregulation in 2 groups of subjects: those who did not develop presyncopal symptoms during 70 degrees passive head-up tilt (HUT), i.e., nonpresyncopal (23 subjects) (5 subjects). Airflow, CO2, blood flow velocity (CBF), ECG, pressure (BP) were recorded. To determine whether influences mean BP (MBP) systolic SP (SBP) on CBF altered subjects, coherencies transfer functions these variables peak (CBFm...
This study describes swallow–breath interaction and phase of respiration with swallow during nonnutritive suck (NNS) in low-risk preterm infants. Suckle swallow, thoracic motion, airflow were measured 16 infants NNS. Logistic regression models used to describe swallow. One hundred seventy-six swallows occurred 35 NNS periods. Swallow–breath as: central apnea (CA), obstructive (OA), or attenuated (AR). AR was associated increased weeks post–first nipple feeding. OA less often males In looking...