Antigen-presenting capabilities of cells infiltrating inflamed corneas.
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Animals↗
Biomedical subjects
D J Coster
Publications and source records attributed to D J Coster.
Corneal transplantation: collection, assessment, storage, and distribution of corneas for grafting.
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Corneal Transplantation↗
Cells infiltrating inflamed and vascularized corneas.
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Animals↗
The role of resident accessory cells in corneal allograft rejection in the rabbit.
Corneal grafts are more likely to be rejected when placed in a vascularized rather than in a normal host cornea. Using immunohistochemical techniques, normal rabbit cornea was found to contain measurable numbers of cells of hemopoietic origin, probably of either macrophage or dendritic lineage. After the deliberate induction of corneal inflammation and neovascularization, the number of these accessory cells was found to increase significantly. There was also a marked increase in the number of T cells present. Enzyme staining indicated a degree of heterogeneity in the infiltrate. The process of rejection of rabbit corneal grafts was found to occur earlier when additional infiltrating cells were present in either donor button or graft bed, and earlier still when the load of infiltrating cells was increased in both donor and recipient. We hypothesize that resident accessory cells of recipient origin may be implicated in graft rejection in vascularized, inflamed corneas.
Animals↗
Effect of inflammation on antibiotic penetration into the anterior segment of the rat eye.
Bacterial infections were established in the right cornea of rats. Animals infected with Staphylococcus aureus were given cephradine intravenously (IV) (40 mg/kg) or topically (50 mg/ml) to both eyes. Animals infected with Pseudomonas aeruginosa were given gentamicin sulfate IV (40 mg/kg) or topically (10 mg/ml). Antibiotic concentrations in cornea and aqueous humor were measured for 4 hrs following dosing using bioassay and radioimmunoassay. In general, infection significantly increased the concentrations obtained soon after dosing. Topically applied cephradine passed through infected eyes more quickly than through normal eyes. Of the pharmacokinetic parameters derived, the permeability of the corneal epithelium to gentamicin in the rat more closely agrees with reported human values than does the rabbit, while the coefficient of elimination from aqueous in the rat is considerably greater than that for either humans or rabbits. This suggests that there are both advantages and disadvantages in using the rat for therapeutic studies of ocular disease.
Administration, Topical↗
Endothelial repair in the rat cornea.
Destruction of the central endothelium of the rat cornea was produced by mechanical injury, total debridement, or transcorneal freezing. Endothelial repair was then studied using specular microscopy, histological staining, pachymetry, and autoradiographic analysis of the incorporation of tritiated thymidine into nuclear DNA. Following an initial process of cell slide to cover the endothelial defect, extensive cellular division occurred at the margins of the wound, with approximately 45% of cells in the wound area showing incorporation of tritiated thymidine. An intact monolayer of irregularly shaped cells was reestablished by 2-14 days, depending on the wound. These results suggest that the corneal endothelial repair processes in the rat are more analogous to those of the rabbit than to those of the cat or primate.
Animals↗
A rat model of bacterial keratitis. Effect of antibiotics and corticosteroid.
A model of bacterial keratitis in rats was developed to quantify the effect of antibiotics and corticosteroid on the infective process. Corneas were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, or Streptococcus pneumoniae. The natural history of infection with these organisms was determined. Groups of animals received topical antibiotics and prednisolone acetate. The effect of treatment on the number of leukocytes and viable bacteria in the corneas was determined. Prednisolone did not influence the effect of the antibiotics; however, steroid treatment alone increased the pseudomonad count as much as 20-fold above the count in untreated eyes. In general, both the antibiotic and steroid treatments were more successful when begun eight hours after infection than when begun at 24 hours. a 1% gentamicin sulfate preparation proved effective against each of the infections, including a pneumococcal strain considered resistant on the basis of in vitro tests.
Animals↗
A comparison of the effects of topical cyclosporine and topical steroid on rabbit corneal allograft rejection.
A comparison was made of the effects of topically applied cyclosporine, and topically applied prednisolone acetate, on the prolongation of corneal allograft survival in a recently developed prevascularized rabbit eye model. Animals were treated four times daily for 28 days postgrafting. Both drugs prolonged graft survival when compared with placebo or no treatment but the corticosteroid was significantly more effective than cyclosporine. Furthermore, anterior segment inflammation and graft vascularization were considerably less marked in animals treated with steroid. No cyclosporine could be detected by radioimmunoassay in anterior chamber fluid removed by paracentesis from grafted animals treated with cyclosporine, suggesting poor absorption of the drug across the cornea.
Administration, Topical↗
Histocompatibility antigen and passenger cell content of normal and diseased human cornea.
The outcome of clinical corneal transplantation depends on the degree of vascularization and inflammation present in the graft bed at the time of the operation, but the reason for this is unclear. Normal, diseased, and rejected human corneas have been examined with an immunoperoxidase staining procedure, employing monoclonal antibodies to class I and II major histocompatibility complex (MHC) antigens and to other leukocyte markers. In particular, departures from normal in the expression of MHC antigens and in the passenger cell distribution in the diseased or rejected corneas were sought. MHC antigen expression did not alter with inflammation, vascularization, or rejection. However, dendritic-like passenger cells, which were found in low numbers throughout the central stroma of normal cornea as well as in basal epithelium, significantly increased in number in vascularized corneas. We suggest that the breakdown of corneal privilege in vascularized eyes may reflect the increased number of accessory cells in the graft bed.
Antibodies, Monoclonal↗
A microprocessor-driven one-operator forced-choice preferential looking apparatus.
Forced-choice preferential looking (FPL) is a behavioural technique for the estimation of visual acuity in preverbal children. We have constructed an electromechanical FPL apparatus controlled by a microprocessor requiring just one operator. Sixty-three babies aged between six weeks and eleven months were evaluated with an overall success rate of 83% in obtaining an acuity measurement. FPL is a practical method for measurement of infant visual acuity in the ophthalmic clinic setting.
Behavioral Medicine↗
Fuchs's heterochromic cyclitis and posterior capsulotomy.
We report a case of intractable glaucoma following an uncomplicated secondary posterior capsulotomy in a 48-year-old male with Fuchs's heterochromic cyclitis. The patient had been free of inflammation and glaucoma since cataract extraction 27 years previously. We also report the results of phenotypic analysis of lymphocytes removed from the anterior chamber.
Anterior Chamber↗
Penetrating corneal transplantation in the inbred rat: a new model.
A model of orthotopic penetrating keratoplasty has been developed in the inbred rat using both avascular and prevascularized recipient beds. The surgical procedure is conventional and can be achieved with standard instrumentation. Isografts into avascular recipient beds (Fisher 344 into Fisher 344 strain combination) were successful and survived indefinitely with excellent corneal function judged either visually by clarity and lack of oedema, or histologically at autopsy. Allografts into avascular beds (DA into Fisher 344 strain combination) became cloudy and oedematous at a median of day 12 postgraft; 43% spontaneously recovered clarity while the remaining 57% remained opaque or became scarred. Penetrating grafts also were performed in eyes prevascularized by the placement of sutures approximately 3 weeks prior to transplantation. Most isografts into prevascularized and inflamed beds underwent a transient episode of oedema, which quickly resolved and was felt to result from postsurgical inflammation. All allografts into prevascularized beds became oedematous and cloudy; 76% went on to fail completely, while 24% cleared without treatment. End-point histology showed normal graft morphology in the isografts; failed allografts showed a picture consistent with immunologic rejection. The model, which allows corneal transplantation to be performed against a constant histocompatibility barrier, may be useful in studies of rejection.
Animals↗
Medical aspects of contact lens wear.
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Bacterial Infections↗
Herpes simplex chorioretinitis in a healthy adult.
A previously healthy 20-year-old man developed bilateral chorioretinitis that included mild anterior uveitis, vitreous cells, multifocal chorioretinitis, and optic nerve swelling that progressed to severe optic neuropathy in one eye. Chorioretinal biopsy specimens cultured herpes simplex type 1 from separate chorioretinal and vitreous samples. Although the visual acuity of one eye remained at light perception, sight in the second eye was saved when treatment with systemic acyclovir and corticosteroids led to resolution of the inflammation. A recurrence was successfully treated with acyclovir alone and the patient shows no evidence of active disease.
Acyclovir↗
Vasoactive intestinal polypeptide immunoreactive nerve fibres in the human eye.
Immunohistochemistry applied to whole-mount preparations was used to investigate the presence and distribution of vasoactive intestinal polypeptide (VIP) immunoreactive nerves in the non-retinal part of the human eye. The choroid has a dense perivascular supply of VIP immunoreactive nerve fibers, and some free nerve endings within the stroma. These nerves enter the choroid in ciliary nerves and also as perivascular networks around the ciliary arteries. Occasional choroidal VIP immunoreactive nerve cell bodies are seen. The ciliary body stroma, close to the iris root has a dense circumferential plexus of VIP immunoreactive nerve fibers that occur both singly and in bundles. The iris root has a circumferential arrangement of bundles from which VIP immunoreactive nerve fibres travel radially in the stroma. They supply the pupillary region with numerous free nerve endings; the sphincter pupillae is not supplied by these nerves. The cornea is devoid of VIP immunoreactive nerves. These findings, together with existing knowledge of the physiological actions of VIP, indicate that VIP immunoreactive nerves are likely to be involved in the functioning of several ocular tissues.
Choroid↗
Enzymatic disaggregation of the infected rat cornea.
Analysis of cell populations in the cornea may be performed rapidly and accurately employing the technique of enzymatic disaggregation. To illustrate this method normal rat corneas and corneas infected 24 and 48 hours previously with Staphylococcus aureus were disaggregated in a solution containing pancreatin and collagenase. The cells released were counted and identified morphologically. These results were compared to cell counts made from histologic sections. Over 95% of the corneal cells were viable after the disaggregation and leukocytes obtained from the infected corneas retained their phagocytic capacity. This approach allows sensitive analysis of cell populations in a wide range of corneal conditions, including infection and allograft rejection.
Animals↗
Herpetic eye disease.
Herpetic keratitis is a common condition which can produce severe complications. The pattern of disease created by the virus depends on an interaction of virus and host mediated mechanisms. The changes in the epithelium are a consequence of the cytopathic effect of the virus and are related directly to virus replication. Changes produced in the stroma are due to inflammatory mechanisms initiated by the presence of virus antigens. The treatment of epithelial disease is aimed at reducing virus replication. The treatment of stromal disease is directed towards suppressing inflammation without increasing virus replication. Various anti-viral agents are available and each has a different mechanism of action and properties which make each anti-viral agent more suitable in particular situations. Many clinical trials have been conducted which indicate the place of anti-viral agents. The management of stromal disease is more complicated and less information is available from clinical trials to indicate the best possible method of treatment.
Adolescent↗