Bioengineered Muscle Implants

2000 ◽  
Author(s):  
G. L. Bowlin ◽  
Barbara Wise ◽  
L. Terracio ◽  
D. G. Simpson
Keyword(s):  
Injection Site ◽  
Cardiac Tissue ◽  
Treatment Options ◽  
Three Dimensional ◽  
Small Animal ◽  
Scar Tissue ◽  
Specific Domain ◽  
Complete Replacement ◽  
Cell Based Therapy ◽  
And Function

Abstract Fundamental research has defined many of the mechanistic events that mediate congenital malformations and the pathological disease processes that alter cardiac structure and function. Despite these efforts, there are a limited number of clinical treatment options available for many of these conditions. In many cases, even for disease processes that cause focal defects in the ventricular wall, the only viable treatment is the complete replacement of the damaged organ by transplant. Unfortunately, the supply of cardiac tissue that is available for transplant therapy remains chronically, and critically, short of demand. The reconstruction of a specific domain of dysfunctional ventricular tissue with a cell-based therapy is a potential avenue of treatment. One of the most direct strategies in this type of treatment regime is the injection of a suspension of fetal or neonatal cardiac myocytes into the injured domain. In small animal models, two limitations have become apparent with this strategy. First, differentiated myocytes do not undergo migration when they are injected into scar tissue and as a result they tend to remain concentrated in the vicinity of the injection site. Second, the myocytes that survive in the injection site are not well integrated into the healthy tissue and contract at rates that are independent of the surrounding myocardium. The long-term objective of this project is to circumvent the limitations of injection therapy by fabricating a cardiac muscle prosthesis that mimics the three dimensional architecture of the intact heart.

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 Targeted Myocardial Restoration with Injectable Hydrogels - In Search of The Holy Grail in Regenerating Damaged Heart Tissue

2021 ◽  
Author(s):  
Faizus Sazzad ◽  
Michał Kuzemczak ◽  
Engracia Loh ◽  
Wellington Wu ◽  
Theo Kofidis
Keyword(s):  
Cardiac Tissue ◽  
Treatment Options ◽  
Heart Tissue ◽  
Current Treatment ◽  
3 Dimensional ◽  
Current State ◽  
Cardiac Surgeons ◽  
Large Animals ◽  
And Function ◽  
A Current

The peril of a 3-dimensional, robust and sustained myocardial restoration by means of Tissue Engineering is that it still remains a largely experimental approach. Prolific protocols have been developed and tested in small and large animals, but as clinical cardiac surgeons, we have not come to the privilege of utilizing any of them in our clinical practice. The question arises: why? The heart is a unique organ, anatomically and functionally. It is not an easy target to replicate with current techniques, or even to support its viability and function. Currently available therapies fail to reverse the loss of functional cardiac tissue, the fundamental pathology remains unaddressed and a heart transplantation is an ultima ratio treatment option. Owing to equivocal results of cell-based therapies, several strategies have been pursued to overcome limitations of the current treatment options. Preclinical data as well as first-in-human studies conducted to date have provided important insights into the understanding of injection-based approaches for myocardial restoration. In the light of the available data, injectable biomaterials suitable for transcatheteter delivery appear to have the highest translational potential,. This article presents a current state-of-the-art in the field of hydrogel-based myocardial restoration therapy.

Clinical Biomechanics: Contributions to the Medical Treatment of Physical Abnormalities

2012 ◽  
Vol 1 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Joseph Hamill ◽  
George Gorton ◽  
Peter Masso
Keyword(s):  
Cerebral Palsy ◽  
Medical Treatment ◽  
Treatment Outcomes ◽  
Clinical Assessment ◽  
Treatment Options ◽  
Three Dimensional ◽  
Structure And Function ◽  
Diverse Field ◽  
The Individual ◽  
And Function

Biomechanics is defined as the application of the laws of mechanics to the study or structure and function of movement. It is a relatively new subdiscipline to the domain of kinesiology. Biomechanics was initially closely associated with the study of sports technique. However, over the years, biomechanics has taken on a much more diverse field of study. In this paper, we will describe the contributions that biomechanics has made to the area of clinical biomechanics research in terms of clinical assessment and outcomes and the design of clinical apparatus. The first example examines a clinical assessment of a cerebral palsy child. The goals of such a clinical assessment are 1) to determine the primary problems with the locomotion capabilities of the individual, 2) to recommend treatment options, and 3) to evaluate treatment outcomes. In the second example, a procedure is described for designing braces for scoliosis patients. For this example, a three-dimensional digital twin is developed using a scanning technique. This example illustrates the research conducted on developing a technique to noninvasively and safely determine the torso deformities resulting from scoliosis. While these examples are but two of a wide variety of examples that could be used, they illustrate the contribution of biomechanics to the clinical world.

scholarly journals Targeted Myocardial Restoration with Injectable Hydrogels—In Search of The Holy Grail in Regenerating Damaged Heart Tissue

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 595
Author(s):  
Faizus Sazzad ◽  
Michał Kuzemczak ◽  
Engracia Loh ◽  
Wellington Wu ◽  
Theo Kofidis
Keyword(s):  
Cardiac Tissue ◽  
Treatment Options ◽  
Heart Tissue ◽  
Current Treatment ◽  
3 Dimensional ◽  
Current State ◽  
Cardiac Surgeons ◽  
Large Animals ◽  
And Function ◽  
A Current

A 3-dimensional, robust, and sustained myocardial restoration by means of tissue engineering remains an experimental approach. Prolific protocols have been developed and tested in small and large animals, but, as clinical cardiac surgeons, we have not arrived at the privilege of utilizing any of them in our clinical practice. The question arises as to why this is. The heart is a unique organ, anatomically and functionally. It is not an easy target to replicate with current techniques, or even to support in its viability and function. Currently, available therapies fail to reverse the loss of functional cardiac tissue, the fundamental pathology remains unaddressed, and heart transplantation is an ultima ratio treatment option. Owing to the equivocal results of cell-based therapies, several strategies have been pursued to overcome the limitations of the current treatment options. Preclinical data, as well as first-in-human studies, conducted to-date have provided important insights into the understanding of injection-based approaches for myocardial restoration. In light of the available data, injectable biomaterials suitable for transcatheter delivery appear to have the highest translational potential. This article presents a current state-of-the-literature review in the field of hydrogel-based myocardial restoration therapy.

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.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Structural Role of rRNAs on the Ribosomal Subunits from E. Coli by Scanning Transmission Electron Microscopy

1981 ◽  
Vol 39 ◽  
pp. 424-425
Author(s):  
M. Boublik ◽  
N. Robakis ◽  
J.S. Wall
Keyword(s):  
Three Dimensional ◽  
Uranyl Acetate ◽  
Dimensional Structure ◽  
Electron Microscopic ◽  
Ribosomal Subunits ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
Scanning Transmission ◽  
And Function

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.

Predicting spatial activity patterns in a neural map from a probabilistic atlas of 3-D reconstructed neurons

1995 ◽  
Vol 53 ◽  
pp. 812-813
Author(s):  
G. Jacobs ◽  
F. Theunissen
Keyword(s):  
Activity Patterns ◽  
Three Dimensional ◽  
Sensory System ◽  
Neural System ◽  
Probabilistic Atlas ◽  
Uniform Sample ◽  
Dimensional Reconstruction ◽  
The Time Domain ◽  
And Function ◽  
Visualization Techniques

In order to understand how the algorithms underlying neural computation are implemented within any neural system, it is necessary to understand details of the anatomy, physiology and global organization of the neurons from which the system is constructed. Information is represented in neural systems by patterns of activity that vary in both their spatial extent and in the time domain. One of the great challenges to microscopists is to devise methods for imaging these patterns of activity and to correlate them with the underlying neuroanatomy and physiology. We have addressed this problem by using a combination of three dimensional reconstruction techniques, quantitative analysis and computer visualization techniques to build a probabilistic atlas of a neural map in an insect sensory system. The principal goal of this study was to derive a quantitative representation of the map, based on a uniform sample of afferents that was of sufficient size to allow statistically meaningful analyses of the relationships between structure and function.

Surgery for Lung Cancer and the Consequences for the Swallow

2016 ◽  
Vol 1 (13) ◽  
pp. 162-168
Author(s):  
Pippa Hales ◽  
Corinne Mossey-Gaston
Keyword(s):  
Lung Cancer ◽  
Treatment Options ◽  
Vocal Cord Palsy ◽  
Subsequent Treatment ◽  
Physiological Reserve ◽  
Palliative Phase ◽  
And Function ◽  
The Impact ◽  
Swallow Function

Lung cancer is one of the most commonly diagnosed cancers across Northern America and Europe. Treatment options offered are dependent on the type of cancer, the location of the tumor, the staging, and the overall health of the person. When surgery for lung cancer is offered, difficulty swallowing is a potential complication that can have several influencing factors. Surgical interaction with the recurrent laryngeal nerve (RLN) can lead to unilateral vocal cord palsy, altering swallow function and safety. Understanding whether the RLN has been preserved, damaged, or sacrificed is integral to understanding the effect on the swallow and the subsequent treatment options available. There is also the risk of post-surgical reduction of physiological reserve, which can reduce the strength and function of the swallow in addition to any surgery specific complications. As lung cancer has a limited prognosis, the clinician must also factor in the palliative phase, as this can further increase the burden of an already compromised swallow. By understanding the surgery and the implications this may have for the swallow, there is the potential to reduce the impact of post-surgical complications and so improve quality of life (QOL) for people with lung cancer.

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