ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Several of the known growth factors either have an effect on corneal tissues or can be isolated from them. Both epidermal growth factor (EGF) and fibroblast growth factor (FGF) stimulate the proliferation of corneal epithelium, keratocytes, and endothelium. Compared to FGF, EGF is more potent in stimulating the growth of endothelial cells; it also increases the tensile strength of corneal stromal wounds. The corneal epithelium produces an angiogenic growth factor as well as a neuronotrophic growth factor. Insulin-like growth factor stimulates the growth of keratocytes and enhances the effect of EGF on the corneal endothelium. Mesodermal growth factor stimulates the proliferation of keratocytes and increases the rate of healing of damaged corneal endothelial cells. It is evident that growth factors have many potential clinical applications especially in accelerating corneal wound repair after surgery, chemical burns, or ulcers, and in increasing the numbers of corneal endothelial cells in aging and diseased corneas, as well as in donor corneas to be used for transplantation. Several parameters require evaluation, e.g., the dose, concentration, combination and formulation, exposure time, receptor affinity, and tissue interdependence of the growth factor(s), as well as the variability in patient response and severity of disease and/or injury. Investigations are also needed for the development of effective delivery systems and for determining whether growth factors are specific and safe in humans. Growth factors are emerging as a new generation of ophthalmic Pharmaceuticals, and they will soon be integrated into the advancing practice of ophthalmic surgery and medicine.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

A comparison between continuous and interrupted techniques of suturing in penetrating keratoplasties was made using autologous grafts in rabbits. Wound strength was determined using both a tensiometer and blow-out pressure measurements. Histologic examination of the wounds was also carried out, and clinical observations were made of the behavior of vascular growth through the wound in prevascularized corneas to further characterize the suturing techniques and the healing process. We found no difference in blow-out pressures between the two groups, but a significant increase in healing in the interrupted suture group, as measured by the tensiometer, was observed. Other differences were noted in the clinical course and histology, including a greater ease of vessels traversing the wound and more inflammatory cells in the wound area with interrupted sutures.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Fifteen eyes in 12 patients with Salzmann's nodular corneal degeneration developed symptoms of recurrent erosion, decreased vision, or both. A history or evidence of ocular surface disease was present in 14 of 15 eyes. Removal of the nodule and accompanying pannus or corneal epithelial basement membrane degeneration, provided symptomatic improvement in all patients.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

This article reports the findings of investigations on an osteo-odonto-keratoprosthesis in an eye that was enucleated owing to severe complications 12 years after implantation. Scanning electron microscopy and electron probe X-ray microanalysis showed extensive resorption of the bone that was used as a supporting element in the kind of transcorneal prosthesis developed by Strampelli. The destructive process, in addition to surgical trauma, has been associated with the early and recurrent bacterial infections relating to the presence of Staphylococcus epidermidis. The need to control the occurrence of primary bacterial infections in traumatized tissues during operations as well as further infectious situations, given the enhanced antibiotic-resistence of bacteria, is emphasized.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The migration and spreading of the corneal epithelial cells adjacent to a wound is the first step in successful epithelial resurfacing. To understand the role of actin filaments and microtubules of the cytoskeletal system in the spreading of corneal epithelial cells, we plated rabbit corneal epithelial cells on a fibronectin matrix and studied the effects of cytochalasin B, which inhibits actin filaments assembly, and colchicine, which inhibits microtubules assembly, on the ability of individual cells to spread. Changes in the morphology of actin filaments and microtubules were also studied using immunofluorescent microscopy. The area of spread epithelial cells depended on the concentration of fibronectin used to coat the surface. In spread cells, stress fibers of actin filaments were evenly distributed throughout the cytoplasm, whereas microtubules were observed only at the perinuclear region. The presence of cytochalasin B during the cell attachment and spreading decreased the area of the spread cells more than did colchicine. However, once the epithelial cells were spread on a fibronectin matrix, cytochalasin B and colchicine each decreased the cell area only slightly, and to the same extent. These results indicate that formation of actin filaments is more important than formation of microtubules to the spreading of corneal epithelial cells.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The repair process of rabbit corneal alkali wounds was examined for 3 weeks in organ culture. The initial wound was inflicted by applying a round filter paper, 5.5 mm in diameter, soaked in 1 N NaOH, for 60 s on the central cornea—the same procedure as used in previous in vivo studies. Epithelial and endothelial healing were determined morphometrically by utilizing a standardized photographic procedure following alizarin red/trypan blue staining. A one-phase healing was discerned both in the epithelium and in the endothelium. The epithelial resurfacing of the wound was completed by 5 days and then remained intact. However, the endothelial defect did not heal completely during the observation period of 21 days. The defect area was, however, consistently reduced in size during the first four days. The present results were compared with previous in vivo findings in rabbit eyes. The advantages of using an in vitro model for initial therapeutic trials are described.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Epidermal growth factor (EGF) is mitogenic for bovine corneal endothelial cells in culture. Pretreatment with either retinoic acid or the synthetic analog CBS-211 A ((E)-4-[2-(2-isopropyl-5-thienyl)propenyl]benzoic acid) at 10-8-10-6M enhanced the EGF effect. This potentiating effect of retinoids contrasts with their intrinsic activity, which results in cell growth inhibition in the absence of growth factor. The present data emphasize the previously reported beneficial effect of retinoic acid on corneal endothelium wound healing. This effect could be related to the potentiation of endogenous growth factors and further underlines the importance of retinoids in the medical treatment of corneal endothelial lesions.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We prospectively evaluated the effect of extended silicone elastomer contact lens wear on the endothelial mosaic of aphakic subjects. Endothelial cell photography and central corneal thickness measurements were performed on 23 eyes of 15 aphakic subjects (mean age 60 ± 10 years). These measurements were made before lens wear(n = 23) and were repeated after 1 year(n = 19) and again after 5 years (n = 10) of lens wear. No statistically significant change in mean endothelial cell size or coefficient of variation of cell size was found. Central corneal thickness was significantly decreased at 1 year and hexagonality was significantly increased at 5 years. Thus, the changes in endothelial morphology usually associated with contact lens wear did not occur with silicone lenses, which are highly permeable to oxygen.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

New high-magnification biomicroscopes, the specular microscope and now the in-tandem confocal microscope, provide new images of the corneal endothelium in vivo. These are not always easy to interpret, and correlation with the morphology of the endothelium as seen in dead, fixed specimens is necessary. One such image is of the anterior surface with the confocal microscope. It exhibits a mosaic of hexagonal cells. This surface has not been specifically investigated previously in fixed preparations and the in vivo appearance does not correlate with the structure deduced from transmission electron micrographs. These indicate that the bases of endothelial cells are in the form of thin processes that would not present an image of clearly defined cell outlines. Therefore, the anterior surface of corneal endothelium stripped from ox and human corneas has been examined with the scanning electron microscope. It was found that the basal cell membranes extend processes to neighbouring cells and that some of these seem to unite. The possibility that these findings are artefactual has been examined by comparing them with published transmission and scanning electron micrographs, and it has been concluded that the processes of the basal cell membranes are real.

ISSN:0277-3740    

出版商:OVID    

年代:1990

数据来源: OVID