Recipes for Reconstituting Skin

1991 ◽  
Vol 113 (2) ◽  
pp. 113-119 ◽  
Author(s):  
E. Bell ◽  
M. Rosenberg ◽  
P. Kemp ◽  
R. Gay ◽  
G. D. Green ◽  
...  
Keyword(s):  
Class Ii ◽  
Collagen Biosynthesis ◽  
Dermal Equivalent ◽  
Cell Matrix ◽  
The Matrix ◽  
Order Of Magnitude ◽  
Threshold Doses ◽  
Secretory Products ◽  
Dermal Cells

Reconstituted Living Skin Equivalent™ (LSE™) is made up of a dermal equivalent (DE) on which keratinocytes are plated where they give rise to a multilayered differentiated epidermis. The dermal equivalent develops through interactions between fibroblasts and collagen fibrils that begin to form after the cell-matrix precursor is cast. The gel that forms as a result of collagen polymerization and fluid trapping is contracted uniformly in all dimensions. By securing it at ends and edges in the mold in which it is cast, the final dimensions, strength and morphology of the forming tissue are altered. The same phenomena are seen in casting tubular tissues for the fabrication of small caliber blood vessel equivalents. The cells of the dermal equivalent are biosynthetically active and enrich the matrix to different degrees with secretory products, depending on how the cells are stimulated and on the presence or absence of an epidermis. Collagen biosynthesis by dermal cells in the DE is sensitive to growth factors, ascorbate concentrations and amino acid pools. Both ascorbate and TGFβ1 increase total collagen biosynthesis at least two-fold by one week after tissue formation. With TGFβ1 present, the capacity of cells in the DE to synthesize collagen increases with time, over a two-week period. If ascorbate (200 μg/ml) is added just after the tissue is cast and daily thereafter, contraction lattice is blocked, and collagen biosynthesis is enhanced relative to contracted controls that had received 200 μg/ml ascorbate once. The increase was nearly an order of magnitude over that of controls and was coordinate with a comparable increase in hyaluronate and sulfated glycosaminoglycan (GAG) production as shown by TCA-precipitable glucosamine in the intercellular matrix of the DE. Both the LSE and the Living Dermal Equivalent™ (LDE™) exhibit complex responses to UV radiation and to various chemicals that are greatly different from responses given by monolayered cells. In general, threshold doses are elevated by one or more orders of magnitude for the tissues as compared with cells in monolayer, with the LSE exhibiting higher thresholds than the DE. The immunogenicity of the human LSE has been tested in vitro. Its cells are shown to be unable to stimulate a response in a mixed lymphocyte reaction (MLR) even after Class II antigens are induced by exposure to cytokines. The basis for the immunologic neutrality of the LSE can be referred to the absence of immune system (IS) cells normally present in skin and to the specific antigenic profiles of nonimmune system (NIS) cells that must be different from those of IS cells and which, even after Class II induction, are not allostimulatory. The generality of immunologic neutrality is an essential consideration in the fabrication of tissue and organ equivalents for grafting. The idea that it can be made a graft property has been formalized in the Neutral Allograft Hypothesis.

The matrix secreted by 804G cells contains laminin-related components that participate in hemidesmosome assembly in vitro

1993 ◽  
Vol 105 (3) ◽  
pp. 753-764 ◽  
Author(s):  
M. Langhofer ◽  
S.B. Hopkinson ◽  
J.C. Jones
Keyword(s):  
Lectin Binding ◽  
Rabbit Antiserum ◽  
Epithelial Cell Line ◽  
Antigenic Relationship ◽  
Matrix Elements ◽  
Cell Matrix ◽  
The Matrix ◽  
Bona Fide ◽  
Functional Analyses

Hemidesmosomes are important adhesion devices found in epithelial cells. They connect the intermediate filament cytoskeleton network with components of the basement membrane zone. 804G cells are an unusual epithelial cell line, since they form bona fide hemidesmosomes when plated on glass or plastic. In this study we tested an hypothesis: that this ability is a consequence of an extracellular component produced by the 804G cells. As probes for our study we generated a rabbit antiserum (J18) and monoclonal antibodies against components of urea-solubilized 804G matrix. Antibodies in the J18 serum recognize major lectin-binding polypeptides of 150, 140 and 135 kDa in the 804G matrix. A monoclonal antibody (5C5) that shows reactivity with the 150 and 135 kDa polypeptides in western immunoblots immunoprecipitates all three molecular mass species, indicating that these polypeptides are part of a matrix complex. Moreover, one, at least, of these matrix elements is immunologically related to laminin, since J18 antibodies selected on fusion protein fragments of a newly characterized laminin variant, laminin B2t (Kallunki et al., J. Cell Biol., 119, 679–694, 1992), react with the 140 kDa polypeptide component of the 804G cell matrix. To undertake functional analyses of 804G matrix, cells of the human epidermal carcinoma line SCC12, which do not assemble bona fide hemidesmosomes in vitro, were cultured on 804G matrix for 24 h and then analysed by confocal immunofluorescence and electron microscopy. In SCC12 cells maintained on 804G cell matrix, hemidesmosomal antigens localize in a distinctive leopard spot pattern that mirrors the distribution of 804G matrix elements. Furthermore, ultrastructural analysis reveals that the 804G cell matrix supports the formation of ‘mature’ hemidesmosomes by SCC12 cells. Thus 804G cell matrix is a remarkable tool for hemidesmosome studies and it will now be of great importance to determine the exact composition of the 804G matrix, especially its structural and antigenic relationship to laminins.

Microhardness of Composite Materials With Different Organic Phases in Deep Class II Cavities: An In Vitro Study

2011 ◽  
Vol 36 (5) ◽  
pp. 502-511 ◽  
Author(s):  
JP Tchorz ◽  
R Doll ◽  
M Wolkewitz ◽  
E Hellwig ◽  
C Hannig
Keyword(s):  
Composite Materials ◽  
In Vitro Study ◽  
Class Ii ◽  
Composite Resins ◽  
Vitro Study ◽  
The Matrix ◽  
Organic Matrices ◽  
Cavity Design

SUMMARY Objective: This study compared the microhardness of three composite resins with different organic matrices in deep class II cavities. Materials and Method: A total of 36 extracted molars were randomly assigned to six groups and standardized class II cavities were prepared. The cavity design comprised three steps in a mesiodistal direction with an increasing depth (2, 4, and 6 mm). Twelve cavities each were restored using Filtek Supreme (FS), Quixfil (QF), and Filtek Silorane (SI). The materials were applied in incremental layers of 2 mm and cured either with Halogen Translux Energy (HTE) (n=18) or LED Bluephase C8 (LED) (n=18). Subsequently, the specimens were cross-sectioned, and microhardness was determined in various depths and at two different distances from the matrix. Results: QF yielded the highest KHN microhardness values (92.67 ± 12.77), followed by FS (65.53 ± 19.52) and SI (57.67 ± 8.33). Composites cured with LED achieved higher KHN values. All materials showed the highest microhardness values within the superficial increments and at a distance of 1000 μm from the matrix.

Variants of integrin β4 subunit in human endometrial adenocarcinoma cells: mediators of ECM-induced differentiation?

1996 ◽  
Vol 74 (6) ◽  
pp. 867-873 ◽  
Author(s):  
Elisabeth Strunck ◽  
Gunter Vollmer
Keyword(s):  
Extracellular Matrix ◽  
Endometrial Adenocarcinoma ◽  
Tumor Development ◽  
Functional Differentiation ◽  
Cell Matrix ◽  
Integrin Β4 ◽  
The Matrix ◽  
And Function ◽  
Cell Matrix Interactions

The influence of extracellular matrix (ECM) on expression and function of integrins in carcinogenesis and differentiation is not well understood, but the importance of altered adhesion features for tumor development and progression is obvious. Integrins as versatile molecules are mainly responsible for mediating cell–matrix interactions and transmembrane signal transduction. They are capable of transducing outside-in signals from ECM components or conversely to organize the matrix by inside-out signaling. In the study presented here, we report that the reconstituted basement membrane, Matrigel™, which induces morphological and functional differentiation of the endometrial adenocarcinoma cell line HEC 1B(L), also regulates the expression of various forms of the integrin β4 subunit. Furthermore, we were able to identify full-length isoforms with and without an altered cytoplasmic domain as well as truncated forms. Our findings suggest a regulatory role of integrin β4 isoforms and fragments in the process of in vitro differentiation of HEC 1B(L).Key words: endometrium, tumor cells, differentiation, extracellular matrix, β4-integrin expression.

scholarly journals Mechanical Interaction of Angiogenic Microvessels With the Extracellular Matrix

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Lowell T. Edgar ◽  
James B. Hoying ◽  
Urs Utzinger ◽  
Clayton J. Underwood ◽  
Laxminarayanan Krishnan ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Blood Vessels ◽  
Element Model ◽  
Mechanical Interaction ◽  
Matrix Mechanics ◽  
Two Photon ◽  
Cell Matrix ◽  
Vascular Elements ◽  
The Matrix

Angiogenesis is the process by which new blood vessels sprout from existing blood vessels, enabling new vascular elements to be added to an existing vasculature. This review discusses our investigations into the role of cell-matrix mechanics in the mechanical regulation of angiogenesis. The experimental aspects of the research are based on in vitro experiments using an organ culture model of sprouting angiogenesis with the goal of developing new treatments and techniques to either promote or inhibit angiogenic outgrowth, depending on the application. Computational simulations were performed to simulate angiogenic growth coupled to matrix deformation, and live two-photon microscopy was used to obtain insight into the dynamic mechanical interaction between angiogenic neovessels and the extracellular matrix. In these studies, we characterized how angiogenic neovessels remodel the extracellular matrix (ECM) and how properties of the matrix such as density and boundary conditions influence vascular growth and alignment. Angiogenic neovessels extensively deform and remodel the matrix through a combination of applied traction, proteolytic activity, and generation of new cell-matrix adhesions. The angiogenic phenotype within endothelial cells is promoted by ECM deformation and remodeling. Sensitivity analysis using our finite element model of angiogenesis suggests that cell-generated traction during growth is the most important parameter controlling the deformation of the matrix and, therefore, angiogenic growth and remodeling. Live two-photon imaging has also revealed numerous neovessel behaviors during angiogenesis that are poorly understood such as episodic growth/regression, neovessel colocation, and anastomosis. Our research demonstrates that the topology of a resulting vascular network can be manipulated directly by modifying the mechanical interaction between angiogenic neovessels and the matrix.

scholarly journals Preparation and Characterization of a Collagen-Liposome-Chondroitin Sulfate Matrix with Potential Application for Inflammatory Disorders Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Oana Craciunescu ◽  
Alexandra Gaspar ◽  
Mihaela Trif ◽  
Magdalena Moisei ◽  
Anca Oancea ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Cell Metabolism ◽  
Local Treatment ◽  
Fibroblast Cell ◽  
Specific Staining ◽  
Inflammatory Disorders ◽  
Cell Matrix ◽  
L929 Fibroblast ◽  
The Matrix

Smart drug delivery systems with controllable properties play an important role in targeted therapy and tissue regeneration. The aim of our study was the preparation andin vitroevaluation of a collagen (Col) matrix embedding a liposomal formulation of chondroitin sulfate (L-CS) for the treatment of inflammatory disorders. Structural studies using Oil Red O specific staining for lipids and scanning electron microscopy showed an alveolar network of nanosized Col fibrils decorated with deposits of L-CS at both periphery and inner of the matrix. The porosity and density of Col-L-CS matrix were similar to those of Col matrix, while its mean pore size and biodegradability had significantly higher and lower values (P<0.05), respectively.In vitrocytotoxicity assays showed that the matrix system induced high cell viability and stimulated cell metabolism in L929 fibroblast cell culture. Light and electron micrographs of the cell-matrix construct showed that cells clustered into the porous structure at 72 h of cultivation.In vitrodiffusion test indicated that the quantity of released CS was significantly lower (P<0.05) after embedment of L-CS within Col matrix. All these results indicated that the biocompatible and biodegradable Col-L-CS matrix might be a promising delivery system for local treatment of inflamed site.

Radiolabeled r-Hirudin as a Measure of Thrombin Activity at, or within, the Rabbit Aorta Wall In Vitro and In Vivo

1994 ◽  
Vol 71 (04) ◽  
pp. 499-506 ◽  
Author(s):  
Mark W C Hatton ◽  
Bonnie Ross-Ouellet
Keyword(s):  
Rabbit Aorta ◽  
Balloon Injury ◽  
Recombinant Hirudin ◽  
Aorta Wall ◽  
Thrombin Activity ◽  
Before And After ◽  
The Matrix

SummaryThe behavior of 125I-labeled recombinant hirudin towards the uninjured and de-endothelialized rabbit aorta wall has been studied in vitro and in vivo to determine its usefulness as an indicator of thrombin activity associated with the aorta wall. Thrombin adsorbed to either sulfopropyl-Sephadex or heparin-Sepharose bound >95% of 125I-r-hirudin and the complex remained bound to the matrix. Binding of 125I-r-hirudin to the exposed aorta subendothelium (intima-media) in vitro was increased substantially if the tissue was pre-treated with thrombin; the quantity of l25I-r-hirudin bound to the de-endothelialized intima-media (i.e. balloon-injured in vitro) correlated positively with the quantity of bound 131I-thrombin (p <0.01). Aortas balloon-injured in vivo were measured for thrombin release from, and binding of 125I-r-hirudin to, the de-endothelialized intimal surface in vitro; 125I-r-hirudin binding correlated with the amount of active thrombin released (p <0.001). Uptake of 125I-r-hirudin by the aorta wall in vivo was proportional to the uptake of 131I-fibrinogen (as an indicator of thrombin activity) before and after balloon injury. After 30 min in the circulation, specific 125I-r-hirudin binding to the uninjured and de-endo- thelialized (at 1.5 h after injury) aorta wall was equivalent to 3.4 (± 2.5) and 25.6 (±18.1) fmol of thrombin/cm2 of intima-media, respectively. Possibly, only hirudin-accessible, glycosaminoglycan-bound thrombin is measured in this way.

The Effect of Adrenaline Infusions on Blood Coagulation in Normal and Haemophilia B Dogs

1966 ◽  
Vol 15 (03/04) ◽  
pp. 349-364 ◽  
Author(s):  
A.H Özge ◽  
H.C Rowsell ◽  
H.G Downie ◽  
J.F Mustard
Keyword(s):  
Body Weight ◽  
Factor Viii ◽  
Factor Ix ◽  
Clotting Factor ◽  
Blood Ph ◽  
Order Of Magnitude ◽  
Dose Dependent ◽  
Generation Test ◽  
Plasma Activity

SummaryThe addition of trace amounts of adrenaline to whole blood in plasma in vitro increased factor VIII, factor IX and whole plasma activity in the thromboplastin generation test. This was dose dependent.Adrenaline infusions less than 22 (μg/kg body weight in normal dogs accelerated clotting, increased factor IX, factor VIII and whole plasma activity in the thromboplastin generation test and caused a fall in blood pH. In a factor IX deficient dog, there was no increase in factor IX activity. After adrenaline infusions, however, the other changes occurred and were of the same order of magnitude as in the normal. Adrenaline in doses greater than 22 μg/kg body weight did not produce as great an effect on clotting in normal or factor IX deficient dogs. The platelet count in the peripheral blood was increased following the infusion of all doses of adrenaline. These observations suggest that the accelerating effect of adrenaline on clotting is not mediated through increase in activity of a specific clotting factor.

Formulation and Evaluation of Galantamine Hydrobromide Floating Matrix Tablet

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
Poreddy Srikanth Reddy ◽  
Penjuri Subhash Chandra Bose ◽  
Vuppula Sruthi ◽  
Damineni Saritha
Keyword(s):  
Sodium Alginate ◽  
Xanthan Gum ◽  
Lag Time ◽  
Matrix Tablets ◽  
In Vitro Dissolution ◽  
Matrix Tablet ◽  
Compression Technique ◽  
Weight Variation ◽  
The Matrix

The aim of the present work was to prepare floating tablets of galantamine HBr using sodium alginate and xanthan gum as matrix forming carriers. Galantamine HBr is used for the treatment of mild to moderate Alzheimer's disease and various other memory impairments, in particular those of vascular origin. The matrix tablet formulations were prepared by varying the concentrations of sodium alginate and xanthan gum. The tablets were prepared by direct compression technique using PVP K-30 as a binder and sodium bicarbonate for development of CO2. The prepared matrix tablets were evaluated for properties such as hardness, thickness, friability, weight variation, floating lag time, compatibility using DSC and FTIR. In vitro dissolution was carried out for 12 hrs in 0.1N HCl at 37±0.5 ºC using USP paddle type dissolution apparatus. It was noted that, all the prepared formulations had desired floating lag time and constantly floated on dissolution medium by maintaining the matrix integrity. The drug release from prepared tablets was found to vary with varying concentration of the polymers, sodium alginate and xanthan gum. From the study it was concluded that floating drug delivery system for galantamine HBr can be prepared by using sodium alginate and xanthan gum as a carrier.

Formulation and Characterization of Glimepiride Nanoparticles for Dissolution Enhancement

2020 ◽  
Vol 10 (5) ◽  
pp. 649-663
Author(s):  
Reena Siwach ◽  
Parijat Pandey ◽  
Harish Dureja
Keyword(s):  
Drug Release ◽  
Dissolution Rate ◽  
Oral Absorption ◽  
In Vitro Release ◽  
Entrapment Efficiency ◽  
Class Ii ◽  
Dissolution Enhancement ◽  
In Vitro Drug Release ◽  
Bcs Class Ii

Background: The rate-limiting step in the oral absorption of BCS class II drugs is dissolution. Their low solubility is one of the major obstacles in the process of drug development. Dissolution rate can be increased by decreasing the particle size to the nano range, eventually leading to increased bioavailability. Objective: : In the present study, glimepiride loaded nanoparticles were prepared to enhance the dissolution rate. The aim of the work was to examine the effect of polymer-drug ratio, solvent-antisolvent ratio and speed of mixing on in vitro release of glimepiride. Methods: Glimepiride is an antidiabetic drug belonging to the BCS class II drugs. The polymeric nanoparticles were formulated according to Box-Behnken Design (BBD) using nanoprecipitation technique. The prepared nanoparticles were evaluated for in vitro drug release, loading capacity, entrapment efficiency, and percentage yield. Result: It was found that NP-8 has maximum in vitro drug release and was selected as an optimized batch. Analysis of Variance (ANOVA) was applied to the in vitro drug release to study the fitness and significance of the model. The batch NP-8 showed 70.34 ± 1.09% in vitro drug release in 0.1 N methanolic HCl and 92.02 ± 1.87% drug release in phosphate buffer pH 7.8. The release data revealed that the nanoparticles followed zero order kinetics. Conclusion: The study revealed that the incorporation of glimepiride into gelucire 50/13 resulted in enhanced dissolution rate.

scholarly journals Ultra-strong bio-glue from genetically engineered polypeptides

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chao Ma ◽  
Jing Sun ◽  
Bo Li ◽  
Yang Feng ◽  
Yao Sun ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Covalent Bond ◽  
Genetically Engineered ◽  
Supramolecular Interactions ◽  
Molar Ratio ◽  
High Adhesion ◽  
Strong Adhesion ◽  
Order Of Magnitude

AbstractThe development of biomedical glues is an important, yet challenging task as seemingly mutually exclusive properties need to be combined in one material, i.e. strong adhesion and adaption to remodeling processes in healing tissue. Here, we report a biocompatible and biodegradable protein-based adhesive with high adhesion strengths. The maximum strength reaches 16.5 ± 2.2 MPa on hard substrates, which is comparable to that of commercial cyanoacrylate superglue and higher than other protein-based adhesives by at least one order of magnitude. Moreover, the strong adhesion on soft tissues qualifies the adhesive as biomedical glue outperforming some commercial products. Robust mechanical properties are realized without covalent bond formation during the adhesion process. A complex consisting of cationic supercharged polypeptides and anionic aromatic surfactants with lysine to surfactant molar ratio of 1:0.9 is driven by multiple supramolecular interactions enabling such strong adhesion. We demonstrate the glue’s robust performance in vitro and in vivo for cosmetic and hemostasis applications and accelerated wound healing by comparison to surgical wound closures.

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