Publications
346 results found
Lee P, Yan P, Ewart P, et al., 2012, Simultaneous measurement and modulation of multiple physiological parameters in the isolated heart using optical techniques, PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, Vol: 464, Pages: 403-414, ISSN: 0031-6768
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- Citations: 25
Kohl P, Bollensdorff C, Morad M, 2012, Progress in Biophysics and Molecular Biology of the Beating Heart, PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, Vol: 110, Pages: 151-153, ISSN: 0079-6107
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- Citations: 4
Quinn TA, Kohl P, 2012, Mechano-sensitivity of cardiac pacemaker function: Pathophysiological relevance, experimental implications, and conceptual integration with other mechanisms of rhythmicity, PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, Vol: 110, Pages: 257-268, ISSN: 0079-6107
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- Citations: 37
Pellis T, Pausler D, Gaiarin M, et al., 2012, Off-patient assessment of pre-cordial impact mechanics among medical professionals in North-East Italy involved in emergency cardiac resuscitation, PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, Vol: 110, Pages: 390-396, ISSN: 0079-6107
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- Citations: 5
Hales PW, Schneider JE, Burton RAB, et al., 2012, Histo-anatomical structure of the living isolated rat heart in two contraction states assessed by diffusion tensor MRI, PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, Vol: 110, Pages: 319-330, ISSN: 0079-6107
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- Citations: 85
Lee P, Taghavi F, Yan P, et al., 2012, In situ optical mapping of voltage and calcium in the heart, PLoS One, Vol: 7, Pages: 1-8, ISSN: 1932-6203
Electroanatomic mapping the interrelation of intracardiac electrical activation with anatomic locations has become an important tool for clinical assessment of complex arrhythmias. Optical mapping of cardiac electrophysiology combines high spatiotemporal resolution of anatomy and physiological function with fast and simultaneous data acquisition. If applied to the clinical setting, this could improve both diagnostic potential and therapeutic efficacy of clinical arrhythmia interventions. The aim of this study was to explore this utility in vivo using a rat model. To this aim, we present a single-camera imaging and multiple light-emitting-diode illumination system that reduces economic and technical implementation hurdles to cardiac optical mapping. Combined with a red-shifted calcium dye and a new near-infrared voltage-sensitive dye, both suitable for use in blood-perfused tissue, we demonstrate the feasibility of in vivo multi-parametric imaging of the mammalian heart. Our approach combines recording of electrophysiologically-relevant parameters with observation of structural substrates and is adaptable, in principle, to trans-catheter percutaneous approaches.
McNary TG, Spitzer KW, Holloway H, et al., 2012, Mechanical modulation of the transverse tubular system of ventricular cardiomyocytes, PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, Vol: 110, Pages: 218-225, ISSN: 0079-6107
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- Citations: 23
Lee P, Klos M, Bollensdorff C, et al., 2012, Simultaneous Voltage and Calcium Mapping of Genetically Purified Human Induced Pluripotent Stem Cell-Derived Cardiac Myocyte Monolayers, CIRCULATION RESEARCH, Vol: 110, Pages: 1556-1563, ISSN: 0009-7330
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- Citations: 138
Lee P, Loew LM, Terrar DA, et al., 2012, Flash Photolysis of Caged Compounds during Simultaneous Imaging of Calcium and Voltage in the Whole Heart using Light-Emitting-Diodes, BIOPHYSICAL JOURNAL, Vol: 102, Pages: 671A-671A, ISSN: 0006-3495
Wang K, Lee P, Gavaghan D, et al., 2012, Action Potential Duration Maps in Homogeneous Cardiac Ventricular Tissue Slices are Independent of Changes in Stimulation Site, BIOPHYSICAL JOURNAL, Vol: 102, Pages: 543A-544A, ISSN: 0006-3495
McNary TG, Spitzer KW, Bridge JHB, et al., 2012, Geometric Changes of Transverse Tubules in Rabbit Cardiac Myocytes during Contraction, BIOPHYSICAL JOURNAL, Vol: 102, Pages: 356A-356A, ISSN: 0006-3495
Kohl P, Bollensdorff C, Quinn TA, 2011, Resolving the M-cell debate: Mechanics Matters, HEART RHYTHM, Vol: 8, Pages: E1-E1, ISSN: 1547-5271
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- Citations: 2
Kohl P, Bollensdorff C, Quinn TA, 2011, Resolving the M-cell debate: mechanics matters., Heart Rhythm, Vol: 8
Quinn TA, Granite S, Allessie MA, et al., 2011, Minimum Information about a Cardiac Electrophysiology Experiment (MICEE): Standardised reporting for model reproducibility, interoperability, and data sharing, Progress in Biophysics and Molecular Biology, Vol: 107, Pages: 4-10, ISSN: 0079-6107
Cardiac experimental electrophysiology is in need of a well-defined Minimum Information Standard for recording, annotating, and reporting experimental data. As a step towards establishing this, we present a draft standard, called Minimum Information about a Cardiac Electrophysiology Experiment (MICEE). The ultimate goal is to develop a useful tool for cardiac electrophysiologists which facilitates and improves dissemination of the minimum information necessary for reproduction of cardiac electrophysiology research, allowing for easier comparison and utilisation of findings by others. It is hoped that this will enhance the integration of individual results into experimental, computational, and conceptual models. In its present form, this draft is intended for assessment and development by the research community. We invite the reader to join this effort, and, if deemed productive, implement the Minimum Information about a Cardiac Electrophysiology Experiment standard in their own work.
Kohl P, Hunter PJ, Winslow RL, 2011, Model interactions: 'It is the simple, which is so difficult', PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, Vol: 107, Pages: 1-3, ISSN: 0079-6107
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- Citations: 5
Bordas R, Gillow K, Lou Q, et al., 2011, Rabbit-specific ventricular model of cardiac electrophysiological function including specialized conduction system, PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, Vol: 107, Pages: 90-100, ISSN: 0079-6107
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- Citations: 54
Kohl P, Sachs F, Franz MR, 2011, Cardiac Mechano-electric Coupling and Arrhythmias, Publisher: Oxford Univ Pr, ISBN: 9780199570164
The book has been thoroughly revised and expanded since publication of the first edition in 2005, extensively updated to reflect recent developments in the ...
Coveney PV, Diaz V, Hunter P, et al., 2011, The Virtual Physiological Human, INTERFACE FOCUS, Vol: 1, Pages: 281-285, ISSN: 2042-8898
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- Citations: 9
Bollensdorff C, Lookin O, Kohl P, 2011, Assessment of contractility in intact ventricular cardiomyocytes using the dimensionless 'Frank-Starling Gain' index, Pflügers Archiv European Journal of Physiology, Vol: 462, Pages: 39-48, ISSN: 0031-6768
This paper briefly recapitulates the Frank-Starling law of the heart, reviews approaches to establishing diastolic and systolic force-length behaviour in intact isolated cardiomyocytes, and introduces a dimensionless index called 'Frank-Starling Gain', calculated as the ratio of slopes of end-systolic and end-diastolic force-length relations. The benefits and limitations of this index are illustrated on the example of regional differences in Guinea pig intact ventricular cardiomyocyte mechanics. Potential applicability of the Frank-Starling Gain for the comparison of cell contractility changes upon stretch will be discussed in the context of intra- and inter-individual variability of cardiomyocyte properties.
Dutta S, Bishop MJ, Pathmanathan P, et al., 2011, Interpreting Optical Mapping Recordings in the Ischemic Heart: A Combined Experimental and Computational Investigation, 6th International Conference on Functional Imaging and Modeling of the Heart (FIMH), Publisher: SPRINGER-VERLAG BERLIN, Pages: 20-27, ISSN: 0302-9743
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- Citations: 5
Quinn TA, Kohl P, 2011, Systems biology of the heart: hype or hope?, ANIMAL MODELS: THEIR VALUE IN PREDICTING DRUG EFFICACY AND TOXICITY, Vol: 1245, Pages: 40-43, ISSN: 0077-8923
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- Citations: 18
Lawford PV, Narracott AV, McCormack K, et al., 2011, Virtual physiological human: training challenges (vol 368, pg 2841, 2010), PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 369, Pages: 494-494, ISSN: 1364-503X
Burton RAB, Quinn TA, Kohl P, 2011, Rediscovering the third coronary artery, European Heart Journal, Vol: 32, Pages: 1435-1437, ISSN: 0195-668X
Brook BS, Kohl P, King JR, 2011, Towards the virtual physiological human: mathematical and computational case studies PREFACE, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 369, Pages: 4145-4148, ISSN: 1364-503X
Kohl P, Camelliti P, 2011, Fibroblast-myocyte connections in the heart., Heart Rhythm
Quinn TA, Bayliss RA, Kohl P, 2011, Mechano-Electric Feedback in the Heart: Effects on Heart Rate and Rhythm, HEART RATE AND RHYTHM: MOLECULAR BASIS, PHARMACOLOGICAL MODULATION AND CLINICAL IMPLICATIONS, Editors: Tripathi, Ravens, Sanguinetti, Publisher: SPRINGER, Pages: 133-151, ISBN: 978-3-642-17574-9
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- Citations: 6
Hales PW, Burton RAB, Bollensdorff C, et al., 2011, Progressive changes in T(1), T(2) and left-ventricular histo-architecture in the fixed and embedded rat heart, Vol: 24, Pages: 836-843, ISSN: 0952-3480
Chemical tissue fixation, followed by embedding in either agarose or Fomblin, is common practice in time-intensive MRI studies of ex vivo biological samples, and is required to prevent tissue autolysis and sample motion. However, the combined effect of fixation and sample embedding may alter tissue structure and MRI properties. We investigated the progressive changes in T(1) and T(2) relaxation times, and the arrangement of locally prevailing cardiomyocyte orientation determined using diffusion tensor imaging, in embedded ex vivo rat hearts fixed using Karnovsky's solution (glutaraldehyde-formaldehyde mix). Three embedding media were investigated: (i) standard agarose (n - 3 hearts); (ii) Fomblin (n - 4 hearts); and (iii) iso-osmotic agarose (n - 3 hearts); in the latter, the osmolarity of the fixative and embedding medium was adjusted to 300 mOsm to match more closely that of native tissue. The T(1) relaxation time in the myocardium showed a pronounced decrease over a 48-h period following embedding in Fomblin (-11.3 +/- 6.2%; mean +/- standard deviation), but was stable in standard agarose-and iso-osmotic agarose-embedded hearts. The mean myocardial T2 relaxation time increased in all embedded hearts: by 35.1 +/- 14.7% with standard agarose embedding, 13.1 +/- 5.6% with Fomblin and 13.3 +/- 1.4% with iso-osmotic agarose. Deviation in the orientation of the primary eigenvector of the diffusion tensor occurred in all hearts (mean angular changes of 6.6 degrees, 3.2 degrees and 1.9 degrees per voxel after 48 h in agarose-, Fomblin-and iso-osmotic agarose- embedded hearts, respectively), indicative of progressive structural changes in myocardial histo-architecture, in spite of previous exposure to fast-acting tissue fixation. Our results suggest that progressive structural changes occur in chemically fixed myocardium, and that the extent of these changes is modulated by the embedding medium, and by osmotic gradients between the fixative in the tissue and the surroundi
Lee P, Bollensdorff C, Quinn TA, et al., 2011, Single-sensor system for spatially resolved, continuous, and multiparametric optical mapping of cardiac tissue, Vol: 8, Pages: 1482-1491, ISSN: 1547-5271
BACKGROUND Simultaneous optical mapping of multiple electro-physiologically relevant parameters in living myocardium is desirable for integrative exploration of mechanisms underlying heart rhythm generation under normal and pathophysiologic conditions. Current multiparametric methods are technically challenging, usually involving multiple sensors and moving parts, which contributes to high logistic and economic thresholds that prevent easy application of the technique. OBJECTIVE The purpose of this study was to develop a simple, affordable, and effective method for spatially resolved, continuous, simultaneous, and multiparametric optical mapping of the heart, using a single camera. METHODS We present a new method to simultaneously monitor multiple parameters using inexpensive off-the-shelf electronic components and no moving parts. The system comprises a single camera, commercially available optical filters, and light-emitting diodes (LEDs), integrated via microcontroller-based electronics for frame-accurate illumination of the tissue. For proof of principle, we illustrate measurement of four parameters, suitable for ratiometric mapping of membrane potential (di-4-ANBDQPQ) and intracellular free calcium (fura-2), in an isolated Langendorff-perfused rat heart during sinus rhythm and ectopy, induced by local electrical or mechanical stimulation. RESULTS The pilot application demonstrates suitability of this imaging approach for heart rhythm research in the isolated heart. In addition, locally induced excitation, whether stimulated electrically or mechanically, gives rise to similar ventricular propagation patterns. CONCLUSION Combining an affordable camera with suitable optical filters and microprocessor-controlled LEDs, single-sensor multiparametric optical mapping can be practically implemented in a simple yet powerful configuration and applied to heart rhythm research. The moderate system complexity and component cost is destined to lower the threshold to broader a
Sayre MR, Koster RW, Botha M, et al., 2010, Part 5: Adult basic life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations, ISSN: 0009-7322
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- Citations: 143
Casero R, Burton RAB, Quinn TA, et al., 2010, Cardiac Valve Annulus Manual Segmentation Using Computer Assisted Visual Feedback in Three-Dimensional Image Data, Pages: 738-741, ISSN: 1557-170X
Annulus manual segmentation is an important tool for the study of valve anatomy and physiology, for the four main valves of the heart (mitral, tricuspid, aortic and pulmonary). In this paper we review two traditional manual segmentation approaches: slice-by-slice and interpolating a sparse set of landmarks with a spline curve. We propose a new Spline Tool for the open source software platform Seg3D, that is fast and improves spatial coherence by providing visual feedback of the segmentation in real time. The Spline Tool was tested successfully on 14 rat hearts, on all four valves.
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