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Papers by Vickery Trinkaus-randall

Research paper thumbnail of A technique for obtaining basal corneal epithelial cells

PubMed, Feb 1, 1985

A technique has been developed for obtaining a cell suspension enriched (89%) in basal corneal ep... more A technique has been developed for obtaining a cell suspension enriched (89%) in basal corneal epithelial cells. Eleven millimeter corneal buttons were removed and placed in culture medium containing low (10 microM) calcium. The posterior half of the stroma was removed with forceps. Three superficial cuts were made with a Bard-Parker blade on the anterior half of the cornea, which was then incubated for 18 hr at 35 degrees C. Nonadherent cells were brushed off after the incubation and basal cells were harvested after a 1-hr incubation in Dispase II. Cell viability estimated by Erythrocin beta exclusion was 90%. Further evidence of viability was that the cells adhered to their native substrate, the denuded basal lamina. The authors protocol provides a method for analyzing the biochemistry of a known population of epithelial cells and makes available a defined source of cells for culture.

Research paper thumbnail of Role of calcium and calmodulin in hemidesmosome formation in vitro

Journal of Cell Biology, Apr 1, 1984

Research paper thumbnail of Injury and EGF mediate the expression of alpha6beta4 integrin subunits in corneal epithelium

Journal of Cellular Biochemistry, 2001

Our goal was to evaluate the role of epidermal growth factor and injury on the expression of inte... more Our goal was to evaluate the role of epidermal growth factor and injury on the expression of integrin subunits alpha6(alpha6) and beta4(beta4). An in vitro wound model was used to evaluate corneal wound repair and cellular migration. Primary rabbit corneal epithelial cell cultures were serum-starved and injured in the presence or absence of EGF or tyrphostin AG1478, an inhibitor of EGF receptor kinase activity. Repair was monitored morphologically and expression was analyzed using in situ hybridization and immunohistochemistry accompanied by confocal microscopy. The addition of EGF to cell cultures induced a dose-dependent increase in beta4 mRNA expression but the constitutive expression of alpha6 was several fold greater. In the wounded cultures there was a rapid change in expression at the edge of the wound that was enhanced with EGF. In our model there was an increase in beta4 and alpha6 protein in migrating cells. Changes in integrin expression were accompanied by a transient increase in activation of the EGF receptor. The addition of tyrphostin inhibited migration of cells and wound repair, the activation of the EGF receptor and phosphorylation of beta4 in the cytoplasm. These data indicate that the activation of the EGF receptor plays a critical role in the regulation of integrin receptors and the mediation of cellular migration.

Research paper thumbnail of Wounding the cornea to learn how it heals

Experimental Eye Research, Apr 1, 2014

Corneal wound healing studies have a long history and rich literature that describes the data obt... more Corneal wound healing studies have a long history and rich literature that describes the data obtained over the past 70 years using many different species of animals and methods of injury. These studies have lead to reduced suffering and provided clues to treatments that are now helping patients live more productive lives. In spite of the progress made, further research is required since blindness and reduced quality of life due to corneal scarring still happens. The purpose of this review is to summarize what is known about different types of wound and animal models used to study corneal wound healing. The subject of corneal wound healing is broad and includes chemical and mechanical wound models. This review focuses on mechanical injury models involving debridement and keratectomy wounds to reflect the authors' expertise.

Research paper thumbnail of Advances in polyvinyl alcohol hydrogel keratoprostheses: Protection against ultraviolet light and fabrication by a molding process

Journal of Biomedical Materials Research, Mar 5, 1997

Our goal was to: 1) modify poly(vinyl alcohol) hydrogels intended for use in a synthetic cornea t... more Our goal was to: 1) modify poly(vinyl alcohol) hydrogels intended for use in a synthetic cornea to absorb ultraviolet light and 2) develop molding procedures for the fabrication of the device. Two ultraviolet light-absorbing monomers were incorporated by copolymerization. The resulting hydrogels protected against ultraviolet light, were not toxic to corneal fibroblasts, and the protection did not diminish during prolonged aqueous exposure. A novel keratoprosthesis molding procedure was developed that made use of the phase transition properties of mixtures of poly(vinyl-trifluoroacetate) and acetonitrile. In this procedure the keratoprosthesis was shaped and a fibrous skirt was bonded to it in a single operation. Composite keratoprostheses were designed and prepared for in vivo testing.

Research paper thumbnail of Mathematical modeling of intracellular and intercellular calcium signaling

Research paper thumbnail of Decoding calcium wave signaling

Advances in Molecular and Cell Biology, 2003

Intercellular calcium waves in astrocytes represent a phenomenon whereby a wave of increases in f... more Intercellular calcium waves in astrocytes represent a phenomenon whereby a wave of increases in free cytosolic calcium concentration ([Ca 2+ ] i ) spreads from an initially stimulated cell across an astrocytic syncytium. Originally it was believed that the mechanism of the spread was ...

Research paper thumbnail of The intracellular distribution of vinculin and alpha2integrin in epithelial cells and chondrocytes

Scanning, 1994

The purpose of this study was to demonstrate the presence of vinculin and alpha2 integrin in chon... more The purpose of this study was to demonstrate the presence of vinculin and alpha2 integrin in chondrocytes in situ and epithelial cells. We also determined that the appropriate fixation and extraction protocols for immunohistochemistry and laser scanning confocal microscopy for an integral membrane protein and an actin‐associated protein in cultured cells and whole tissue was different. Cultured epithelial cells, whole mount human cornea and avian cartilage were fixed and prepared using a number of standard procedures used for indirect fluorescence immunohistochemistry. The distribution of vinculin was cell‐type and fixation‐specific. Chondrocytes and cultured epithelial cells demonstrated vinculin in areas that appear to be associated with filamentous actin. Vinculin was associated with cell membranes in human cornea. The expression of alpha2 integrin observed in chondrocytes fixed with methanol, paraformaldehyde, or formaldehyde is consistent with its role in cell‐substrate interaction, but may also suggest a role in dividing and differentiating cells. The localization of alpha2 integrin in human corneal epithelia supports its role as a cell‐cell adhesion molecule. The cytoplasmic distribution of vinculin and alpha2 integrin in tissues fixed without detergent extraction suggests that the fixation step may be sufficient for antibody penetration and antigen extraction. These studies are the first report of vinculin and alpha2 integrin in embryonic chondrocytes. In addition we have shown that confocal laser scanning microscopy combined with proper fixation and extraction protocols may optimize the localization of antigens in cultured and whole mount cells.

Research paper thumbnail of Cornea

Research paper thumbnail of Hypoxia modulates the development of a corneal stromal matrix model

Experimental Eye Research, May 1, 2018

Research paper thumbnail of Implantation of a Synthetic Cornea: Design, Development and Biological Response

Artificial Organs, Nov 12, 2008

Our goal was to evaluate 3 different designs of synthetic corneas in vivo. All devices had a tran... more Our goal was to evaluate 3 different designs of synthetic corneas in vivo. All devices had a transparent hydrogel center molded to a porous peripheral skirt. Over 30 devices were implanted into rabbits and followed for up to 6 months. The devices were preseeded with rabbit stro-ma1 fibroblasts, which enhanced the rate of fibroplasia. The anterior surface of the hydrogel was modified using argon rf plasma treatments. Clinical examinations were performed, and histological analyses were conducted on tissue throughout the time course. Our optimal model ranged from 4.5 to 6 mm and had an extended porous skirt

Research paper thumbnail of Type V collagen regulates the assembly of collagen fibrils in cultures of bovine vascular smooth muscle cells

Journal of Cellular Biochemistry, 2000

Vascular smooth muscle cells (SMCs), the major cellular constituent of the medial layer of an art... more Vascular smooth muscle cells (SMCs), the major cellular constituent of the medial layer of an artery, synthesize the majority of connective tissue proteins, including fibrillar collagen types I, III, and V/XI. Proper collagen synthesis and deposition, which are important for the integrity of the arterial wall, require the antioxidant vitamin C. Vitamin C serves as cofactor for the enzymes prolyl and lysyl hydroxylase, which are responsible for the proper hydroxylation of collagen. Here, the role of type V collagen in the assembly of collagen fibrils in the extracellular matrix (ECM) of cultured vascular SMCs was investigated. Treatment of SMCs with vitamin C resulted in a dramatic induction in the levels of the cell-layer associated pepsin-resistant type V collagen, whereas only a minor induction in the levels of types I and III collagen was detected. Of note, the deposition of type V collagen was accompanied by the formation of striated collagen fibrils in the ECM. Immunohistochemistry demonstrated that type V collagen, but not type I collagen, became masked as collagen fibrils matured. Furthermore, the relative ratio of type V to type I collagen decreased as the ECM matured as a function of days in culture, and this decrease was accompanied by an increase in the diameter of collagen fibrils. Together these results suggest that the masking of type V collagen is caused by its internalization on continuous deposition of type I collagen on the exterior of the fibril. Furthermore, they suggest that type V collagen acts as framework for the initial assembly of collagen molecules into heterotypic fibrils, regulating the diameter and architecture of these fibrils.

Research paper thumbnail of New insights in wound response and repair of epithelium

Journal of Cellular Physiology, Jan 28, 2013

Research paper thumbnail of Injury Causes Communication Between Corneal Epithelial and Neuronal Cells in a Co-Culture Model

Investigative Ophthalmology & Visual Science, Apr 28, 2009

Research paper thumbnail of P2X7 is Necessary for Wound-Induced Ca2+ Mobilization and Cytoskeletal Rearrangements in the Corneal Epithelium

Investigative Ophthalmology & Visual Science, Jun 11, 2015

Research paper thumbnail of P2X7 Expression in Vitrectomy Samples

Investigative Ophthalmology & Visual Science, Jun 16, 2013

Research paper thumbnail of P2X7 receptor - the communicator in the cornea

Investigative Ophthalmology & Visual Science, Jul 22, 2019

Research paper thumbnail of Pannexin1, an ion channel, is negligible in corneal epithelium of NONcNZO10/LtJ Type 2 diabetic mice compared to control

Investigative Ophthalmology & Visual Science, Jun 10, 2020

Research paper thumbnail of Epithelial abrasion induces distinct changes in interaction of 2 ion channel proteins Pannexin1 and P2X7 in diabetic mice

Investigative Ophthalmology & Visual Science, Jun 21, 2021

Research paper thumbnail of The Role of P2X7 Receptors on the Expression of Proteoglycans and Collagens in the Corneal Stroma

Investigative Ophthalmology & Visual Science, Apr 17, 2010

Research paper thumbnail of A technique for obtaining basal corneal epithelial cells

PubMed, Feb 1, 1985

A technique has been developed for obtaining a cell suspension enriched (89%) in basal corneal ep... more A technique has been developed for obtaining a cell suspension enriched (89%) in basal corneal epithelial cells. Eleven millimeter corneal buttons were removed and placed in culture medium containing low (10 microM) calcium. The posterior half of the stroma was removed with forceps. Three superficial cuts were made with a Bard-Parker blade on the anterior half of the cornea, which was then incubated for 18 hr at 35 degrees C. Nonadherent cells were brushed off after the incubation and basal cells were harvested after a 1-hr incubation in Dispase II. Cell viability estimated by Erythrocin beta exclusion was 90%. Further evidence of viability was that the cells adhered to their native substrate, the denuded basal lamina. The authors protocol provides a method for analyzing the biochemistry of a known population of epithelial cells and makes available a defined source of cells for culture.

Research paper thumbnail of Role of calcium and calmodulin in hemidesmosome formation in vitro

Journal of Cell Biology, Apr 1, 1984

Research paper thumbnail of Injury and EGF mediate the expression of alpha6beta4 integrin subunits in corneal epithelium

Journal of Cellular Biochemistry, 2001

Our goal was to evaluate the role of epidermal growth factor and injury on the expression of inte... more Our goal was to evaluate the role of epidermal growth factor and injury on the expression of integrin subunits alpha6(alpha6) and beta4(beta4). An in vitro wound model was used to evaluate corneal wound repair and cellular migration. Primary rabbit corneal epithelial cell cultures were serum-starved and injured in the presence or absence of EGF or tyrphostin AG1478, an inhibitor of EGF receptor kinase activity. Repair was monitored morphologically and expression was analyzed using in situ hybridization and immunohistochemistry accompanied by confocal microscopy. The addition of EGF to cell cultures induced a dose-dependent increase in beta4 mRNA expression but the constitutive expression of alpha6 was several fold greater. In the wounded cultures there was a rapid change in expression at the edge of the wound that was enhanced with EGF. In our model there was an increase in beta4 and alpha6 protein in migrating cells. Changes in integrin expression were accompanied by a transient increase in activation of the EGF receptor. The addition of tyrphostin inhibited migration of cells and wound repair, the activation of the EGF receptor and phosphorylation of beta4 in the cytoplasm. These data indicate that the activation of the EGF receptor plays a critical role in the regulation of integrin receptors and the mediation of cellular migration.

Research paper thumbnail of Wounding the cornea to learn how it heals

Experimental Eye Research, Apr 1, 2014

Corneal wound healing studies have a long history and rich literature that describes the data obt... more Corneal wound healing studies have a long history and rich literature that describes the data obtained over the past 70 years using many different species of animals and methods of injury. These studies have lead to reduced suffering and provided clues to treatments that are now helping patients live more productive lives. In spite of the progress made, further research is required since blindness and reduced quality of life due to corneal scarring still happens. The purpose of this review is to summarize what is known about different types of wound and animal models used to study corneal wound healing. The subject of corneal wound healing is broad and includes chemical and mechanical wound models. This review focuses on mechanical injury models involving debridement and keratectomy wounds to reflect the authors' expertise.

Research paper thumbnail of Advances in polyvinyl alcohol hydrogel keratoprostheses: Protection against ultraviolet light and fabrication by a molding process

Journal of Biomedical Materials Research, Mar 5, 1997

Our goal was to: 1) modify poly(vinyl alcohol) hydrogels intended for use in a synthetic cornea t... more Our goal was to: 1) modify poly(vinyl alcohol) hydrogels intended for use in a synthetic cornea to absorb ultraviolet light and 2) develop molding procedures for the fabrication of the device. Two ultraviolet light-absorbing monomers were incorporated by copolymerization. The resulting hydrogels protected against ultraviolet light, were not toxic to corneal fibroblasts, and the protection did not diminish during prolonged aqueous exposure. A novel keratoprosthesis molding procedure was developed that made use of the phase transition properties of mixtures of poly(vinyl-trifluoroacetate) and acetonitrile. In this procedure the keratoprosthesis was shaped and a fibrous skirt was bonded to it in a single operation. Composite keratoprostheses were designed and prepared for in vivo testing.

Research paper thumbnail of Mathematical modeling of intracellular and intercellular calcium signaling

Research paper thumbnail of Decoding calcium wave signaling

Advances in Molecular and Cell Biology, 2003

Intercellular calcium waves in astrocytes represent a phenomenon whereby a wave of increases in f... more Intercellular calcium waves in astrocytes represent a phenomenon whereby a wave of increases in free cytosolic calcium concentration ([Ca 2+ ] i ) spreads from an initially stimulated cell across an astrocytic syncytium. Originally it was believed that the mechanism of the spread was ...

Research paper thumbnail of The intracellular distribution of vinculin and alpha2integrin in epithelial cells and chondrocytes

Scanning, 1994

The purpose of this study was to demonstrate the presence of vinculin and alpha2 integrin in chon... more The purpose of this study was to demonstrate the presence of vinculin and alpha2 integrin in chondrocytes in situ and epithelial cells. We also determined that the appropriate fixation and extraction protocols for immunohistochemistry and laser scanning confocal microscopy for an integral membrane protein and an actin‐associated protein in cultured cells and whole tissue was different. Cultured epithelial cells, whole mount human cornea and avian cartilage were fixed and prepared using a number of standard procedures used for indirect fluorescence immunohistochemistry. The distribution of vinculin was cell‐type and fixation‐specific. Chondrocytes and cultured epithelial cells demonstrated vinculin in areas that appear to be associated with filamentous actin. Vinculin was associated with cell membranes in human cornea. The expression of alpha2 integrin observed in chondrocytes fixed with methanol, paraformaldehyde, or formaldehyde is consistent with its role in cell‐substrate interaction, but may also suggest a role in dividing and differentiating cells. The localization of alpha2 integrin in human corneal epithelia supports its role as a cell‐cell adhesion molecule. The cytoplasmic distribution of vinculin and alpha2 integrin in tissues fixed without detergent extraction suggests that the fixation step may be sufficient for antibody penetration and antigen extraction. These studies are the first report of vinculin and alpha2 integrin in embryonic chondrocytes. In addition we have shown that confocal laser scanning microscopy combined with proper fixation and extraction protocols may optimize the localization of antigens in cultured and whole mount cells.

Research paper thumbnail of Cornea

Research paper thumbnail of Hypoxia modulates the development of a corneal stromal matrix model

Experimental Eye Research, May 1, 2018

Research paper thumbnail of Implantation of a Synthetic Cornea: Design, Development and Biological Response

Artificial Organs, Nov 12, 2008

Our goal was to evaluate 3 different designs of synthetic corneas in vivo. All devices had a tran... more Our goal was to evaluate 3 different designs of synthetic corneas in vivo. All devices had a transparent hydrogel center molded to a porous peripheral skirt. Over 30 devices were implanted into rabbits and followed for up to 6 months. The devices were preseeded with rabbit stro-ma1 fibroblasts, which enhanced the rate of fibroplasia. The anterior surface of the hydrogel was modified using argon rf plasma treatments. Clinical examinations were performed, and histological analyses were conducted on tissue throughout the time course. Our optimal model ranged from 4.5 to 6 mm and had an extended porous skirt

Research paper thumbnail of Type V collagen regulates the assembly of collagen fibrils in cultures of bovine vascular smooth muscle cells

Journal of Cellular Biochemistry, 2000

Vascular smooth muscle cells (SMCs), the major cellular constituent of the medial layer of an art... more Vascular smooth muscle cells (SMCs), the major cellular constituent of the medial layer of an artery, synthesize the majority of connective tissue proteins, including fibrillar collagen types I, III, and V/XI. Proper collagen synthesis and deposition, which are important for the integrity of the arterial wall, require the antioxidant vitamin C. Vitamin C serves as cofactor for the enzymes prolyl and lysyl hydroxylase, which are responsible for the proper hydroxylation of collagen. Here, the role of type V collagen in the assembly of collagen fibrils in the extracellular matrix (ECM) of cultured vascular SMCs was investigated. Treatment of SMCs with vitamin C resulted in a dramatic induction in the levels of the cell-layer associated pepsin-resistant type V collagen, whereas only a minor induction in the levels of types I and III collagen was detected. Of note, the deposition of type V collagen was accompanied by the formation of striated collagen fibrils in the ECM. Immunohistochemistry demonstrated that type V collagen, but not type I collagen, became masked as collagen fibrils matured. Furthermore, the relative ratio of type V to type I collagen decreased as the ECM matured as a function of days in culture, and this decrease was accompanied by an increase in the diameter of collagen fibrils. Together these results suggest that the masking of type V collagen is caused by its internalization on continuous deposition of type I collagen on the exterior of the fibril. Furthermore, they suggest that type V collagen acts as framework for the initial assembly of collagen molecules into heterotypic fibrils, regulating the diameter and architecture of these fibrils.

Research paper thumbnail of New insights in wound response and repair of epithelium

Journal of Cellular Physiology, Jan 28, 2013

Research paper thumbnail of Injury Causes Communication Between Corneal Epithelial and Neuronal Cells in a Co-Culture Model

Investigative Ophthalmology & Visual Science, Apr 28, 2009

Research paper thumbnail of P2X7 is Necessary for Wound-Induced Ca2+ Mobilization and Cytoskeletal Rearrangements in the Corneal Epithelium

Investigative Ophthalmology & Visual Science, Jun 11, 2015

Research paper thumbnail of P2X7 Expression in Vitrectomy Samples

Investigative Ophthalmology & Visual Science, Jun 16, 2013

Research paper thumbnail of P2X7 receptor - the communicator in the cornea

Investigative Ophthalmology & Visual Science, Jul 22, 2019

Research paper thumbnail of Pannexin1, an ion channel, is negligible in corneal epithelium of NONcNZO10/LtJ Type 2 diabetic mice compared to control

Investigative Ophthalmology & Visual Science, Jun 10, 2020

Research paper thumbnail of Epithelial abrasion induces distinct changes in interaction of 2 ion channel proteins Pannexin1 and P2X7 in diabetic mice

Investigative Ophthalmology & Visual Science, Jun 21, 2021

Research paper thumbnail of The Role of P2X7 Receptors on the Expression of Proteoglycans and Collagens in the Corneal Stroma

Investigative Ophthalmology & Visual Science, Apr 17, 2010