ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Allograft rejection is the leading cause of corneal transplant failure. Sensitization of the host by donor histocompatibility antigens is best explained by a two-signal model of lymphocyte activation. One signal is provided by the serologically-defined, major histocompatibility antigens (HLA-A, -B in man, H2-K, -D in mice). The second signal is provided either by leukocyte-defined antigens (HLA -D, -DR in man, la in mice) or by minor histocompatibility antigens. Once host sensitization has occurred, host lymphocytes can recognize and destroy donor cells possessing any or all donor histocompatibility antigens. The prevention of host sensitization is the ideal way to avoid rejection. This may be achieved by tissue typing and matching or by elimination of one of the potent signals. Selective depletion of dendritic Langerhans' cell - om the corneal epithelium removes leukocyte-defined antigens and reduces the incidence of rejection.The treatment of established rejection episode in sensitized hosts has been accomplished with corticosteroids. Experimental studies with cyclosporin-A are promising and suggest that recipients with graft rejection may be safely and successfully treated with this immunosuppressive drug

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Because we found that steroid can retard autolysis of the stored cornea, we planned to add the agent to the tissue culture medium used for storing isolated corneas. The purpose of our experiment was to determine the rate at which steroid enters the stored cornea and the rate at which it will be released from the graft postoperatively.Rabbit corneas were stored for 2 days at 4°C in MK medium containing radiolabeled hydrocortisone. Discs from these corneas were grafted onto allogeneic animals. Identical discs were used for determining the amount of the drugs present per disc by scintillation counting. Autoradiography of the donor tissue and recipient cornea containing the graft was also done. Both scintillation counting and autoradiography showed that hydrocortisone entered the corneal tissue stored at 4°C and that by 24 hours postoperatively, most of the steroid disappeared from the graft and the graft-bed. In view of the rapid disappearance of steroid from the graft and graft-bed postoperatively, it appears that corneal donor tissue stored in steroid solution should not create a problem with respect to wound healing and microbial invasion.

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

We examined 11 soft contact lens patients with ocular changes resembling Theodore's superior limbic keratoconjunctivitis. All had developed symptoms several months or longer after beginning use of Preflex® or the identically formulated Bausch and Lomb cleaner. Dermatologic patch testing failed to demonstrate delayed hypersensitivity to thimerosal or other lens care solution components. Chronic exposure to epithelial toxic detergents and preservatives in these cleaning solutions is strongly implicated as the cause for the keratoconjunctivitis. The use of preservative-free saline solutions, cleaning solutions of lesser toxicity, and thermal sterilization may allow patients to resume wearing soft lenses following resolution of the keratoconjunctivitis.

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Epithelial wounds 7.5 mm in diameter and 0.2 mm in depth were made with a trephine in both eyes of 24 rabbits. The right eyes were left uncovered and soft contact lenses were placed on the left eyes. Two types of lenses were used, Type A lenses (39% water) and Type B lenses, (58% water). Healing was studied by SEM at 8, 16, 24, and 48 hours. Uncovered eyes in all animals showed signs of epithelial cell migration beginning at 16 hours. Eyes covered with Type A lenses showed no signs of epithelial cell migration at any time period. Eyes covered with Type B lenses showed signs of epithelial cell migration beginning at 16 hours. Lenses containing 39% water with a low 02transmissibility (8.9 X 10-11DK/L) correlate with inhibition of cell migration, while lenses containing 58% water with a high 02transmissibility (4.3 x 10-9DK/L) do not

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Lectine-colloidal gold technique has shown, both by transmission (TEM) and by scanning (SEM) electron microscopy, the presence of concanavalin A receptors on the surface of corneal epithelial cells. Further study with use of this technique should be of benefit in ascertaining corneal immunological response.

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTThe source of fibronectin in corneal wound healing was investigated in rabbits by inducing experimental bullous keratopathy using benzalkonium chloride. The location of fibronectin was detected by indirect immunofluorescent microscopy. One day after irrigation with benzalkonium chloride, no endothelial cells were found and epithelial damage was observed. Specific fluorescence for fibronectin was observed at the limbal area, which suggests the vascular origin of fibronectin, and at the stromal side of Descemet's membrane. On day 3, endothelial healing became active. Fibronectin from limbal circulation was much more prominent than at day 1, and it diffused into the central portion of the cornea. Both the endothelial and stromal side of Descemet's membrane stained for fibronectin. On day 7, fibronectin from limbal circulation decreased, as did fibronectin in the stroma. Retrocorneal membrane was observed and stained strongly for fibronectin. Our study demonstrates that fibronectin was released from limbal blood vessels and diffused into the stroma, and that endothelial cells may synthesize fibronectin during the healing process.

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

A 51-year-old man with a long history of recurrent herpes keratouveitis of the right eye developed multinodular skin lesions of the right lower lid and forehead after penetrating keratoplasty. The inflammatory lesions, which enlarged slowly and coalesced over 15 months, eventually involved the sclera and interfered with ocular motility. After central corneal perforation and replacement of the corneal graft, the skin lesions resolved spontaneously. The distribution and the temporal relation of the skin lesions to corneal graft suggest that they were causally related.

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

We examined a patient with keratouveitis secondary to a bee sting. Neurotrophic keratitis complicated the course. Dense corneal opacification eventually necessitated a penetrating keratoplasty. Electron microscopic examination of the cornea revealed large intrastromal crystals. These crystals may represent mellitin or cholesterol. Ocular complications of bee and wasp stings are discussed.

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Refractive corneal surgery has been under investigation for more than 30 years. Although several different surgical procedures have evolved, none has gained widespread popularity. Complex technology, slow visual recovery, and lack of predictability have been some of the major problems. In an attempt to overcome these difficulties, the feasibility of corneal implants made of alloplastic materials has been tested. This paper documents the successful use of high-water content hydro-gels in non-human primates. Although these materials appear to be biologically compatible with corneal stroma, it was found that their position within the cornea was critical. Placement of these lenses at less than 50% corneal depth was universally unsuccessful, whereas placement at 50% or deeper was successful in all cases. Although stability of these materials within the cornea seems likely, the ultimate usefulness of the technique will depend on the ability to generate a predictable change in curvature at the anterior corneal surface

ISSN:0277-3740    

出版商:OVID    

年代:1982

数据来源: OVID