Keratocyte networks visualised in the living cornea using vital dyes

1993 ◽  
Vol 106 (2) ◽  
pp. 685-691 ◽  
Author(s):  
C.A. Poole ◽  
N.H. Brookes ◽  
G.M. Clover
Keyword(s):  
Three Dimensional ◽  
Corneal Stroma ◽  
Molecular Probes ◽  
Dead Cell ◽  
High Concentration ◽  
Vital Dyes ◽  
Dimensional Network ◽  
Cell Processes ◽  
Connective Tissue Matrix ◽  
Tissue Matrix

Fluorescent viability probes have been used to visualise and investigate the viability, morphology and organisation of the keratocyte within the stroma of the intact living cornea. The live cell probe, calcien-AM, in combination with a dead cell probe, ethidium homodimer (Live/Dead Assay, Molecular Probes, U.S.A.) proved superior to earlier generation vital dyes such as fluorescein diacetate or 5,6-carboxyfluorescein diacetate, initially used in combination with ethidium bromide. The ubiquitous distribution of esterase enzymes that cleave calcien-AM within the keratocyte cytoplasm produced a high concentration of fluorescently active calcein throughout the cell, including fine cell processes. Epi-illuminated fluorescence microscopy on transparent corneal dissections subsequently revealed details of keratocyte microanatomy and three-dimensional network organisation in situ. Three morphologically discrete subpopulations of keratocytes were identified: two formed relatively small bands of cells, immediately subjacent to either Bowman's or Descemet's membranes, the third subpopulation constituting the majority of keratocytes typically located within the corneal stroma. The results indicate that calcein-AM is able to penetrate intact living cornea revealing cell viability, and it also has the capacity to ‘trace’ cellular elements and reveal fine structure within a dense connective tissue matrix.

Toward a kinetic theory of connective tissue micromechanics

1993 ◽  
Vol 74 (2) ◽  
pp. 665-681 ◽  
Author(s):  
S. M. Mijailovich ◽  
D. Stamenovic ◽  
J. J. Fredberg
Keyword(s):  
Connective Tissue ◽  
Three Dimensional ◽  
Elastic Fibers ◽  
Tissue Elasticity ◽  
Field Equations ◽  
Fiber Network ◽  
Rate Dependent ◽  
Connective Tissue Matrix ◽  
Tissue Matrix ◽  
And Diffusion

The aim of this study is to develop unifying concepts at the microstructural level to account for macroscopic connective tissue dynamics. We establish the hypothesis that rate-dependent and rate-independent dissipative stresses arise in the interaction among fibers in the connective tissue matrix. A quantitative theoretical analysis is specified in terms of geometry and material properties of connective tissue fibers and surrounding constituents. The analysis leads to the notion of slip and diffusion boundary layers, which become unifying concepts in understanding mechanisms that underlie connective tissue elasticity and energy dissipation during various types of loading. The complex three-dimensional fiber network is simplified to the interaction of two ideally elastic fibers that dissipate energy on slipping interface surfaces. The effects of such interactions are assumed to be expressed in the aggregate matrix. Special solutions of the field equations are obtained analytically, whereas the general solution of the model field equations is obtained numerically. The solutions lead to predictions of tissue behavior that are qualitatively, if not quantitatively, consistent with reports of a variety of dynamic moduli, their dependencies on the rate and amplitude of load application, and some features associated with preconditioning.

Normal atrial and ventricular myocardial structures

2018 ◽  
Author(s):  
Damián Sánchez-Quintana ◽  
José Angel Cabrera
Keyword(s):  
Cardiac Cycle ◽  
Myocardial Function ◽  
Fibrous Tissue ◽  
Three Dimensional ◽  
Atrial Septum ◽  
Structural Basis ◽  
Connective Tissue Matrix ◽  
Atrial Activation ◽  
Heart Functions ◽  
Tissue Matrix

The heart functions by means of a three-dimensional arrangement of myofibres supported by an extracellular matrix which plays an important role in maintaining the size and shape of the heart. In both atria, the structure of the walls and the atrial septum confers a three-dimensional arrangement of muscle bundles and myoarchitecture that allows preferential electrical intra- and interatrial conduction which is important for a better understanding of atrial activation and arrhythmias. The myoarchitecture within the ventricular walls has a three-dimensional arrangement of myofibres, within a supporting matrix of fibrous tissue, which changes orientation from being oblique in the subepicardium to circumferential in the middle and to longitudinal in the subendocardium, allowing the chambers to change in shape and size through the cardiac cycle. Within each ventricle, the circumferential portion is the thickest transmurally, with the longitudinal portion the thinnest. The three-dimensional arrangement of the ventricular mesh serves to realign the myocytes during ventricular contraction, accounting for the extent of systolic mural thickening. Abnormal myoarchitecture in combination with alterations in the connective tissue matrix provide the structural basis for abnormalities in myocardial function.

Laminar structure of the heart: ventricular myocyte arrangement and connective tissue architecture in the dog

1995 ◽  
Vol 269 (2) ◽  
pp. H571-H582 ◽  
Author(s):  
I. J. LeGrice ◽  
B. H. Smaill ◽  
L. Z. Chai ◽  
S. G. Edgar ◽  
J. B. Gavin ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Three Dimensional ◽  
Length Distribution ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Tangential Section ◽  
Connective Tissue Matrix ◽  
The Right ◽  
Tissue Matrix ◽  
Number Of Branches

We have studied the three-dimensional arrangement of ventricular muscle cells and the associated extracellular connective tissue matrix in dog hearts. Four hearts were potassium-arrested, excised, and perfusion-fixed at zero transmural pressure. Full-thickness segments were cut from the right and left ventricular walls at a series of precisely located sites. Morphology was visualized macroscopically and with scanning electron microscopy in 1) transmural planes of section and 2) planes tangential to the epicardial surface. The appearance of all specimens was consistent with an ordered laminar arrangement of myocytes with extensive cleavage planes between muscle layers. These planes ran radially from endocardium toward epicardium in transmural section and coincided with the local muscle fiber orientation in tangential section. Stereological techniques were used to quantify aspects of this organization. There was no consistent variation in the cellular organization of muscle layers (48.4 +/- 20.4 microns thick and 4 +/- 2 myocytes across) transmurally or in different ventricular regions (23 sites in 6 segments), but there was significant transmural variation in the coupling between adjacent layers. The number of branches between layers decreased twofold from subepicardium to midwall, whereas the length distribution of perimysial collagen fibers connecting muscle layers was greatest in the midwall. We conclude that ventricular myocardium is not a uniformly branching continuum but a laminar hierarchy in which it is possible to identify three axes of material symmetry at any point.

scholarly journals Poly-Epsilon-Lysine Hydrogels with Dynamic Crosslinking Facilitates Cell Proliferation

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3851
Author(s):  
Nestor Lopez Mora ◽  
Matthew Owens ◽  
Sara Schmidt ◽  
Andreia F. Silva ◽  
Mark Bradley
Keyword(s):  
Biomedical Applications ◽  
Cell Attachment ◽  
Three Dimensional ◽  
Cellular Migration ◽  
Cellular Processes ◽  
Dimensional Network ◽  
Proliferation And Differentiation ◽  
Cell Processes ◽  
Arginine Glycine Aspartic Acid ◽  
Imine Bond

The extracellular matrix (ECM) is a three-dimensional network within which fundamental cell processes such as cell attachment, proliferation, and differentiation occur driven by its inherent biological and structural cues. Hydrogels have been used as biomaterials as they possess many of the ECM characteristics that control cellular processes. However, the permanent crosslinking often found in hydrogels fails to recapitulate the dynamic nature of the natural ECM. This not only hinders natural cellular migration but must also limit cellular expansion and growth. Moreover, there is an increased interest in the use of new biopolymers to create biomimetic materials that can be used for biomedical applications. Here we report on the natural polymer poly-ε-lysine in forming dynamic hydrogels via reversible imine bond formation, with cell attachment promoted by arginine-glycine-aspartic acid (RGD) incorporation. Together, the mechanical properties and cell behavior of the dynamic hydrogels with low poly-ε-lysine quantities indicated good cell viability and high metabolic activity.

Normal atrial and ventricular myocardial structures

ESC CardioMed ◽  
2018 ◽  
pp. 72-76
Author(s):  
Damián Sánchez-Quintana ◽  
José Angel Cabrera
Keyword(s):  
Extracellular Matrix ◽  
Fibrous Tissue ◽  
Three Dimensional ◽  
Atrial Septum ◽  
Structural Basis ◽  
Ventricular Contraction ◽  
Connective Tissue Matrix ◽  
Heart Functions ◽  
Tissue Matrix ◽  
Shape And Size

The heart functions by means of a three-dimensional arrangement of myofibres supported by an extracellular matrix which plays an important role in maintaining the size and shape of the heart. In both atria, the structure of the walls and the atrial septum confers a three-dimensional arrangement of muscle bundles and myoarchitecture that allows preferential electrical intra- and interatrial conduction which is important for a better understanding of atrial activation and arrhythmias. The myoarchitecture within the ventricular walls has a three-dimensional arrangement of myofibres, within a supporting matrix of fibrous tissue, which changes orientation from being oblique in the subepicardium to circumferential in the middle and to longitudinal in the subendocardium, allowing the chambers to change in shape and size through the cardiac cycle. Within each ventricle, the circumferential portion is the thickest transmurally, with the longitudinal portion the thinnest. The three-dimensional arrangement of the ventricular mesh serves to realign the myocytes during ventricular contraction, accounting for the extent of systolic mural thickening. Abnormal myoarchitecture in combination with alterations in the connective tissue matrix provide the structural basis for abnormalities in myocardial function.

Development of Mucoadhesive Buccal Drug Delivery System of Propranolol Hydrochloride Using Aster ericoides Mucilage

2020 ◽  
Vol 10 (2) ◽  
pp. 133-148
Author(s):  
Ankaj Kaundal ◽  
Pravin Kumar ◽  
Rajendra Awasthi ◽  
Giriraj T. Kulkarni
Keyword(s):  
Buccal Cavity ◽  
Three Dimensional ◽  
Hot Water ◽  
Fickian Diffusion ◽  
Aster Ericoides ◽  
Dimensional Network ◽  
Buccal Tablet ◽  
Significant Difference ◽  
Volunteer Group

Aim: The study was aimed to develop mucoadhesive buccal tablets using Aster ericoides leaves mucilage. Background : Mucilages are naturally occurring high-molecular-weight polyuronides, which have been extensively studied for their application in different pharmaceutical dosage forms. Objective: The objective of the present research was to establish the mucilage isolated from the leaves of Aster ericoides as an excipient for the formulation of the mucoadhesive buccal tablet. Method: The mucilage was isolated from the leaves of Aster ericoides by maceration, precipitated with acetone and characterized. Tablets were prepared using wet granulation technique and evaluated for various official tests. Results: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Conclusion: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Other: However, to prove the potency of the polymer, in vivo bioavailability studies in human volunteers are needed along with chronic toxicity studies in suitable animal models.

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