bromochloroacetic-acid and hydroxyethyl-methacrylate

The outgrowth of corneal epithelial cells onto a polymeric substrate is expected to be the primary event in the epithelialization of a synthetic corneal graft. To study the effects of polymer surface properties on corneal epithelial cell outgrowth, a quantitative in vitro cell outgrowth assay was done. Polymers with systematic variations in hydroxyl content were used as outgrowth substrates. These polymers were characterized by electron spectroscopy for chemical analysis for elemental surface composition and by captive air-bubble contact angle for surface wettability. Circular corneal buttons were punched from excised rabbit corneas, placed onto these substrates, and incubated in a hormonally enriched culture medium. Outgrowth of the epithelial cells was allowed to proceed onto the substrates for 4 days. The outgrowth areas were measured, and an outgrowth index was calculated for each substrate by comparing it with tissue culture polystyrene substrate. The highest outgrowth generally occurred on substrates with intermediate wettabilities (captive air-bubble contact angles of approximately 45-75 degree); it was less on substrates of lower or higher wettabilities. Protein coatings of albumin, immunoglobulin G (IgG), fibronectin, and culture medium were found to lower the wettabilities of native substrates. Albumin and IgG precoating were shown to reduce epithelial cell outgrowth; fibronectin precoating was shown to improve outgrowth on most substrates. These results suggest that epithelial cell outgrowth is influenced by both substrate and protein interactions.

Topics: Actins; Adsorption; Albumins; Cell Division; Cells, Cultured; Cornea; Epithelial Cells; Epithelium; Factor VIII; Fibronectins; Fluorescent Antibody Technique; Immunoglobulin G; Keratins; Kinetics; Methacrylates; Methylmethacrylates; Polymers; Surface Properties; Vimentin

Immunoperoxidase stains were performed on normal and neoplastic tissue from prostate, colon, thyroid, lung, nerve, uterus, and placenta embedded in both plastic (glycolmethacrylate [GMA]) and paraffin. Positive results in plastic section were obtained for carcinoembryonic antigen (CEA), keratin, epithelial membrane antigen (EMA), thyroglobulins, S-100, prostate-specific antigen, human chorionic gonadotrophin (HCG), and beta-HCG. More delicate staining with more precise localization of antigens is noted. Superior (paraformaldehyde) fixation and cold processing followed by GMA polymerization (4 degrees C) allow for optimum antigen survival. After fixation, tissue processing involves a series of 0.1 mol/L phosphate buffer rinses with sucrose and ammonium chloride in a conventional dip-and-dunk processor placed in a 4 degrees C cold room. Acetone dehydrations are used before GMA infiltration, cold polymerization, and sectioning. Before immunoperoxidase staining, the plastic section is digested in .25% bovine trypsin for ten minutes. The immunoperoxidase methods described can be useful when small biopsies are routinely embedded in plastic to obtain improved histologic (hematoxylin-eosin) sections. There may also be research applications in quantifying antigen expression in benign, dysplastic, and neoplastic tissues by examining the stains under high power.

Topics: Adenocarcinoma; Antigens; Carcinoembryonic Antigen; Colonic Neoplasms; Humans; Immunoenzyme Techniques; Keratins; Male; Membrane Glycoproteins; Methacrylates; Mucin-1; Paraffin; Placenta; Prostatic Hyperplasia; Thyroglobulin; Thyroid Gland