scholarly journals A fundamental evaluation of the electrical properties and function of cardiac transverse tubules

2020 ◽  
Vol 1867 (3) ◽  
pp. 118502 ◽  
Author(s):  
S.H. Vermij ◽  
H. Abriel ◽  
J.P. Kucera
Keyword(s):  
Electrical Properties ◽  
Transverse Tubules ◽  
And Function

scholarly journals Relationships between neuronal structure and function

1984 ◽  
Vol 112 (1) ◽  
pp. 129-145 ◽  
Author(s):  
J. P. Miller ◽  
G. A. Jacobs
Keyword(s):  
Electrical Properties ◽  
Ultrastructural Level ◽  
Directional Sensitivity ◽  
Surprising Result ◽  
Neuronal Structure ◽  
Dendritic Length ◽  
Structural And Electrical Properties ◽  
Dendritic Branching ◽  
And Function ◽  
Different Levels

The geometry and electrical properties of a neurone determine how synaptic inputs and endogenously generated currents are integrated and transformed into the signals it transmits to other cells. The dependence of neuronal integration upon dendritic geometry has been studied extensively over the last three decades, both by experimentalists and by theoreticians. We review some of the general principles that have emerged from this work, and summarize recent studies that serve to illustrate these principles. The discussion is organized around the analysis of neuronal structure at three different levels. At the ‘macroscopic’ level, we show how the dendritic branching structure of an identified interneurone in the cricket cercal afferent system determines the directional sensitivity within its receptive field. At the ‘microscopic’ level, we illustrate the dependence of synaptic efficacy upon dendritic length, and demonstrate a very surprising result: that the extension (or ‘growth’) of a dendrite out beyond the point of a synaptic contact can increase the efficacy of that synapse. At the ‘ultrastructural’ level, we show how the structural and electrical properties of dendritic spines might have profound effects upon synaptic integration.

scholarly journals Self-assembly, Stability and the Electrical Characteristics of Cell Membranes

1999 ◽  
Vol 52 (1) ◽  
pp. 117 ◽  
Author(s):  
Hans G. L. Coster
Keyword(s):  
Electrical Properties ◽  
Self Assembly ◽  
Cell Membranes ◽  
Mechanical Analysis ◽  
Fundamental Research ◽  
Statistical Mechanical ◽  
Commercially Important ◽  
The Stability ◽  
And Function ◽  
Molecular Organisation

Living cells are enveloped in an ultra thin ( ~ 6 nm) membrane which consists basically of a bi-molecular film of lipid molecules in which are embedded functional proteins that perform a variety of functions, including energy transduction, signalling, transport of ions (and other molecules) etc., and also acts as a diffusion barrier between the cell interior (cytoplasm) and the external medium. A simple statistical mechanical analysis of the self-assembly of the membrane from its components provides useful insights into the molecular organisation of the membrane and its electrical properties. The stability of the structure is also closely connected to its electrical properties and this has provided not only a useful tool for fundamental research but has spawned also applications, some of which have had a major impact in biomedical research and are now being exploited commercially. An overview is given of the rapid progress made in our understanding of the physics of both the molecular organisation and function of cell membranes and some of the fascinating and socially and commercially important applications that have flowed from this.

3D bioprinted and integrated platforms for cardiac tissue modeling and drug testing

2021 ◽  
Author(s):  
Uijung Yong ◽  
Byeongmin Kang ◽  
Jinah Jang
Keyword(s):  
Electrical Properties ◽  
Real Time ◽  
Drug Testing ◽  
Cardiac Tissue ◽  
The Body ◽  
Cardiac Tissues ◽  
Tissue Modeling ◽  
Recent Trends ◽  
Cardiac Models ◽  
And Function

Abstract Recent advances in biofabrication techniques, including 3D bioprinting, have allowed for the fabrication of cardiac models that are similar to the human heart in terms of their structure (e.g., volumetric scale and anatomy) and function (e.g., contractile and electrical properties). The importance of developing techniques for assessing the characteristics of 3D cardiac substitutes in real time without damaging their structures has also been emphasized. In particular, the heart has two primary mechanisms for transporting blood through the body: contractility and an electrical system based on intra and extracellular calcium ion exchange. This review introduces recent trends in 3D bioprinted cardiac tissues and the measurement of their structural, contractile, and electrical properties in real time. Cardiac models have also been regarded as alternatives to animal models as drug-testing platforms. Thus, perspectives on the convergence of 3D bioprinted cardiac tissues and their assessment for use in drug development are also presented.

Structure and function of channel-forming peptaibols

1993 ◽  
Vol 26 (4) ◽  
pp. 365-421 ◽  
Author(s):  
M. S. P. Sansom
Keyword(s):  
Electrical Properties ◽  
Molecular Level ◽  
Structure And Function ◽  
Atomic Resolution ◽  
Excitable Cells ◽  
Channel Proteins ◽  
Physiological Processes ◽  
Transport Of Ions ◽  
And Function

Transport of ions through channels is fundamental to a number of physiological processes, especially the electrical properties of excitable cells (Hille, 1992). To understand this process at a molecular level requires atomic resolution structures of channel proteins.

scholarly journals Electroactive Polymeric Composites to Mimic the Electromechanical Properties of Myocardium in Cardiac Tissue Repair

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 53
Author(s):  
Kaylee Meyers ◽  
Bruce P. Lee ◽  
Rupak M. Rajachar
Keyword(s):  
Electrical Properties ◽  
Wound Repair ◽  
Cardiac Tissue ◽  
Cell Attachment ◽  
Polymeric Composites ◽  
Scar Tissue ◽  
Structure And Function ◽  
Force Transmission ◽  
Stem Cell Delivery ◽  
And Function

Due to the limited regenerative capabilities of cardiomyocytes, incidents of myocardial infarction can cause permanent damage to native myocardium through the formation of acellular, non-conductive scar tissue during wound repair. The generation of scar tissue in the myocardium compromises the biomechanical and electrical properties of the heart which can lead to further cardiac problems including heart failure. Currently, patients suffering from cardiac failure due to scarring undergo transplantation but limited donor availability and complications (i.e., rejection or infectious pathogens) exclude many individuals from successful transplant. Polymeric tissue engineering scaffolds provide an alternative approach to restore normal myocardium structure and function after damage by acting as a provisional matrix to support cell attachment, infiltration and stem cell delivery. However, issues associated with mechanical property mismatch and the limited electrical conductivity of these constructs when compared to native myocardium reduces their clinical applicability. Therefore, composite polymeric scaffolds with conductive reinforcement components (i.e., metal, carbon, or conductive polymers) provide tunable mechanical and electroactive properties to mimic the structure and function of natural myocardium in force transmission and electrical stimulation. This review summarizes recent advancements in the design, synthesis, and implementation of electroactive polymeric composites to better match the biomechanical and electrical properties of myocardial tissue.

scholarly journals SEARCHING FOR ELECTRICAL PROPERTIES, PHENOMENA AND MECHANISMS IN THE CONSTRUCTION AND FUNCTION OF CHROMOSOMES

2013 ◽  
Vol 6 (7) ◽  
pp. e201303007 ◽  
Author(s):  
Ivan Kanev ◽  
Wai-Ning Mei ◽  
Akira Mizuno ◽  
Kristi DeHaai ◽  
Jennifer Sanmann ◽  
...  
Keyword(s):  
Electrical Properties ◽  
And Function

scholarly journals Resurgence of Cardiac T-Tubule Research

Physiology ◽  
2007 ◽  
Vol 22 (3) ◽  
pp. 167-173 ◽  
Author(s):  
Fabien Brette ◽  
Clive Orchard
Keyword(s):  
Cardiac Function ◽  
Ventricular Myocytes ◽  
Current Knowledge ◽  
Surface Membrane ◽  
Structure And Function ◽  
Transverse Tubules ◽  
Pathological Conditions ◽  
And Function ◽  
Review Current ◽  
Cardiac Ventricular Myocytes

The transverse tubules of mammalian cardiac ventricular myocytes are invaginations of the surface membrane. Recent data have revealed that their structure and function are more complex than previously believed. Here, we review current knowledge about their role in cardiac function, focusing on Ca2+ signaling and changes observed in pathological conditions.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

The Effect of Oxidized Cholesterol on the Aorta of Rabbits- Scanning Electron Microscopic Observations

1982 ◽  
Vol 40 ◽  
pp. 340-341
Author(s):  
S. K. Pena ◽  
C. B. Taylor ◽  
J. Hill ◽  
J. Safarik
Keyword(s):  
Cholesterol Biosynthesis ◽  
Cholesterol Content ◽  
Arterial Injury ◽  
Electron Microscopic ◽  
Aortic Smooth Muscle ◽  
Oxidized Cholesterol ◽  
Initial Event ◽  
Membrane Structure And Function ◽  
Scanning Electron Microscopic ◽  
And Function

Introduction: Oxidized cholesterol derivatives have been demonstrated in various cell cultures to be very potent inhibitors of 3-hvdroxy-3- methylglutaryl Coenzyme A reductase which is a principle regulator of cholesterol biosynthesis in the cell. The cholesterol content in the cells exposed to oxidized cholesterol was found to be markedly decreased. In aortic smooth muscle cells, the potency of this effect was closely related to the cytotoxicity of each derivative. Furthermore, due to the similarity of their molecular structure to that of cholesterol, these oxidized cholesterol derivatives might insert themselves into the cell membrane, alter membrane structure and function and eventually cause cell death. Arterial injury has been shown to be the initial event of atherosclerosis.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

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