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Microscopic magnetic resonance imaging reveals high prevalence of third coronary artery in human and rabbit heart.
AIM: The human coronary tree is commonly assumed to have two roots: the left and right coronary arteries (LCA and RCA, respectively). However, a third coronary artery (TCA) has been observed in humans and animals, usually arising from the right anterior aortic sinus near the RCA. Using high-resolution ma…
Hydroxychloroquine reduces heart rate by modulating the hyperpolarization-activated current If: Novel electrophysiological insights and therapeutic potential.
BACKGROUND: Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. OBJECTIVES: The purpose of this study was to investigate the propensity of hydroxychloroquine (HCQ) to cause bradycardi…
Rearrangement of atrial bundle architecture and consequent changes in anisotropy of conduction constitute the 3-dimensional substrate for atrial fibrillation.
BACKGROUND: Anisotropy of conduction facilitates re-entry and is, therefore, a key determinant of the stability of atrial fibrillation (AF). Little is known about the effect of AF on atrial bundle architecture and consequent changes in anisotropy of conduction and maintenance of AF. METHODS AND RESULTS: Direct…
Minimum Information about a Cardiac Electrophysiology Experiment (MICEE): standardised reporting for model reproducibility, interoperability, and data sharing.
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).…
Three-dimensional models of individual cardiac histoanatomy: tools and challenges.
There is a need for, and utility in, the acquisition of data sets of cardiac histoanatomy, with the vision of reconstructing individual hearts on the basis of noninvasive imaging, such as MRI, enriched by reference to detailed atlases of serial histology obtained from representative samples. These data sets woul…
Progressive changes in T₁, T₂ and left-ventricular histo-architecture in the fixed and embedded rat heart.
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 a…
Rediscovering the third coronary artery.
A second right coronary artery is not at all unusual, as described here from Oxford, England.
Measurement and analysis of sarcomere length in rat cardiomyocytes in situ and in vitro.
Sarcomere length (SL) is an important determinant and indicator of cardiac mechanical function; however, techniques for measuring SL in living, intact tissue are limited. Here, we present a technique that uses two-photon microscopy to directly image striations of living cells in cardioplegic conditions, both in situ (…
Development of an anatomically detailed MRI-derived rabbit ventricular model and assessment of its impact on simulations of electrophysiological function.
Recent advances in magnetic resonance (MR) imaging technology have unveiled a wealth of information regarding cardiac histoanatomical complexity. However, methods to faithfully translate this level of fine-scale structural detail into computational whole ventricular models are still in their infancy, and, th…
Resolving the three-dimensional histology of the heart
Cardiac histo-anatomical structure is a key determinant in all aspects of cardiac function. While some characteristics of micro- and macrostructure can be quantified using non-invasive imaging methods, histology is still the modality that provides the best combination of resolution and identification of cellular/s…
Fast measurement of sarcomere length and cell orientation in Langendorff-perfused hearts using remote focusing microscopy.
RATIONALE: Sarcomere length (SL) is a key indicator of cardiac mechanical function, but current imaging technologies are limited in their ability to unambiguously measure and characterize SL at the cell level in intact, living tissue. OBJECTIVE: We developed a method for measuring SL and regional cell…
Axial stretch of rat single ventricular cardiomyocytes causes an acute and transient increase in Ca2+ spark rate.
We investigate acute effects of axial stretch, applied by carbon fibers (CFs), on diastolic Ca2+ spark rate in rat isolated cardiomyocytes. CFs were attached either to both cell ends (to maximize the stretched region), or to the center and one end of the cell (to compare responses in stretched and nonstretched h…
Mapping cardiac microstructure of rabbit heart in different mechanical states by high resolution diffusion tensor imaging: A proof-of-principle study.
Myocardial microstructure and its macroscopic materialisation are fundamental to the function of the heart. Despite this importance, characterisation of cellular features at the organ level remains challenging, and a unifying description of the structure of the heart is still outstanding. Here, we optimised diffus…
Macro-micro imaging of cardiac-neural circuits in co-cultures from normal and diseased hearts.
The autonomic nervous system plays an important role in the modulation of normal cardiac rhythm, but is also implicated in modulating the heart's susceptibility to re-entrant ventricular and atrial arrhythmias. The mechanisms by which the autonomic nervous system is pro-arrhythmic or anti-arrhythmi…
Generation of histo-anatomically representative models of the individual heart: tools and application.
This paper presents methods to build histo-anatomically detailed individualized cardiac models. The models are based on high-resolution three-dimensional anatomical and/or diffusion tensor magnetic resonance images, combined with serial histological sectioning data, and are used to investigate individualized…
Two-pore Channels (TPC2s) and Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) at Lysosomal-Sarcoplasmic Reticular Junctions Contribute to Acute and Chronic β-Adrenoceptor Signaling in the Heart.
Ca(2+)-permeable type 2 two-pore channels (TPC2) are lysosomal proteins required for nicotinic acid adenine dinucleotide phosphate (NAADP)-evoked Ca(2+) release in many diverse cell types. Here, we investigate the importance of TPC2 proteins for the physiology and pathophysiology of the heart. NAAD…
Towards high-resolution cardiac atlases: Ventricular anatomy descriptors for a standardized reference frame
Increased resolution in cardiac Magnetic Resonance Imaging (MRI) and growing interest in the effect of small structures in electrophysiology of the heart pose new challenges for cardiac atlases. In this paper we discuss the limitations of current atlas-building models when trying to incorporate cardiac small st…