Cornea, histology

In contrast, implantation of four small pieces of poly(N-palmitoyl-hydroxyproline ester) into four rabbit corneas elicited no pathological response in three corneas and a very mild inflammatory response in one cornea. Histological examination of the corneas 4 weeks postimplantation showed no invading blood vessels or migrating inflammatory cells in the area around the implants. 

Implants in the rabbit corneas exhibited no observable inflammatory characteristics over a period of 6 weeks. Compared to other previously tested polymers, the inertness of these polyanhydrides rivals that of the biocompatible poly(hydroxyethyl methacrylate) and ethylene-vinyl acetate copolymer. Histological examination of the removed corneas also revealed the absence of inflammatory cells (21)... 

In our laboratory, the viability of excised porcine buccal mucosa was assessed using histological evaluation and a 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) biochemical assay which has previously been used in assessing the viability of excised buccal mucosa and cornea [49, 50], Histological evaluation of tissue demonstrated that the buccal epithelium appeared viable up to 9 h postmortem, and this was supported by the MTT biochemical assay, which indicated that viability was maintained for up to 12 h [80], Therefore, we recommend that all permeation experiments using porcine buccal mucosa be performed within 9-12 h of animal death. 

The cornea enables the penetration of rays of light inside the eye, thanks to completely particular optical capacities allied to its great fragility largely due to its distant origin within the aquatic species. We will see how the histology of the cornea helps to understand this permanent miracle. 

The cornea is the transparent window of the eye it is 500 pm thick at the centre and histologically made of, from the snrface to the inside ... 

The histological architecture of the cornea and specifically that of the stroma. 

The lesions tended to be more severe and have a greater duration at higher doses. Histologically, the cornea appeared with patchy denudation of the epithelium and infiltration of neutrophils to the site of injury (Ballantyne et al, 1974). In general, more severe eye exposures have resulted from CN compared to CS agent. 

Richter, M.N., Wachtlin, J., Bechrakis, N.E., Hoffinann, F. (2006). Keratoplasty after mustard gas injury clinical outcome and histology. Cornea 25 467-9. 

Histologic cross-section of the cornea reveals five identifiable layers epithelinm. Bowman s layer, stroma, Descemet s membrane, and endothelium. Fluid surrounds the cornea in the forms of the tear film in front and the aqneons behind. The various corneal layers combine to form a structure that is approximately 633 mcm thick at the inferior periphery, 673 mcm at the superior periphery, and 515 mcm thick centrally. The adult corneal diameter measmes 11 to 12 mm horizontally and 9 to 11 mm vertically, creating a horizontally oriented ellipse. The radius of ciuvature of the central 3-mm optical zone ranges between 7.5 and 8.0 mm. 

Histological examination. Corneas are removed at the end of the experiment as well as at defined intervals after surgery and/or treatment and fixed in formalin for histological examination. Newly formed vessels and the presence of inflammatory cells are detected by hematoxylin/eosin staining or specific immunohistochemical... 

Animals of the control group received physiological salt solution according to the same scheme. Histological studies of cornea were carried out on the next, fifth, tenth, twenty-fifth, and sixtieth days after trauma. Treatment of sections was conducted by conventional histological methods. 

The effects of a test substance on the cornea are measured quantitatively as an increase in thickness (swelling), subjectively as scores for corneal opacity, the area of corneal involvement, fluorescein penetration, and morphological changes to the corneal epithelium. Two additional endpoints may be incorporated into the protocol or used ad hoc to supplement existing data. This includes the use of histopathology to confirm or identify the extent of irritancy at the histology level (especially if the irritancy fells between moderate and severe) and the use of confocal microscopy to determine the extent and depth of ocular injury [69, 70], see also Section 4.2.3. 

A group of ten rabbits had daily applications of 0.1 ml 0.05% CR in PEG 300 to the surface of the cornea for ten successive days and were examined periodically for the following five months (Ballantyne et al., 1975). The only effect seen was during the dosing period and was a just detectable conjunctival hyperaemia persisting for a few minutes after the instillation. Over the 5-month follow-up period, there were no adverse effects on the eye, and histology of the eye at 5 months showed no abnormalities. 

The solid (0.5-5.0 mg) caused lacrimation at all doses, blepharitis that increased with dose and lasted up to a week, and chemosis at 5 mg, which was mild and lasted 3 days. Minimal iritis and keratitis, of 24 hours duration, were seen in two of five animals receiving 5 mg. At concentrations of 1% and higher, CS in solution caused conjunctivitis and iritis, chemosis, keratitis, and corneal vascularization the lesion was more severe and lasted longer with the higher doses. Histological examination indicated patchy denudation of corneal epithelium and a neutrophilic infiltration of the cornea.17... 

Fig. 27. Histologic cut through the human cornea after staining the bound hyaluronic acid with the help of the Avidinper-oxidase-method The surface of the corneal endothelium shows a thin but dense colour after streptomyces-hyaluro-nidase treatment to ensure the specificity of the staining method in the first place. Hyaluronic acid had been injected into the anterior chamber 5 minutes prior to this treatment and was followed by an irriga-tion-/aspiration maneuvre with 100 ml BSS (light microscopy)...

Twenty-five per cent of patients with Gaucher s disease have a typical eye injury—a wedge-shaped, yellowish streak with its base directed inward close to the cornea and its apex directed outward toward the canthus. Although one would suspect that this anomaly results from the conglomeration of Gaucher cells in the sclera, no such cells have been detected on histological examination. 

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