An experimental model of mycobacterial infection under corneal flaps.

In order to develop a new experimental animal model of infection with Mycobacterium chelonae in keratomileusis, we conducted a double-blind prospective study on 24 adult male New Zealand rabbits. One eye of each rabbit was submitted to automatic lamellar keratotomy with the automatic corneal shaper under general anesthesia. Eyes were immunosuppressed by a single local injection of methyl prednisolone. Twelve animals were inoculated into the keratomileusis interface with 1 microl of 10(6) heat-inactivated bacteria (heat-inactivated inoculum controls) and 12 with 1 microl of 10(6) live bacteria. Trimethoprim drops (0.1%, w/v) were used as prophylaxis for the surgical procedure every 4 h (50 microl, qid). Animals were examined by 2 observers under a slit lamp on the 1st, 3rd, 5th, 7th, 11th, 16th, and 23rd postoperative days. Slit lamp photographs were taken to document clinical signs. Animals were sacrificed when corneal disease was detected and corneal samples were taken for microbiological analysis. Eleven of 12 experimental rabbits developed corneal disease, and M. chelonae could be isolated from nine rabbits. Eleven of the 12 controls receiving a heat-inactivated inoculum did not develop corneal disease. M. chelonae was not isolated from any of the control rabbits receiving a heat-inactivated inoculum, or from the healthy cornea of control rabbits. Corneal infection by M. chelonae was successfully induced in rabbits submitted to keratomileusis. To our knowledge, this is the first animal model of M. chelonae infection following corneal flaps for refractive surgery to be described in the literature and can be used for the analysis of therapeutic responses.

An experimental model of mycobacterial infection under corneal flaps

In order to develop a new experimental animal model of infection with Mycobacterium chelonae in keratomileusis, we conducted a double-blind prospective study on 24 adult male New Zealand rabbits. One eye of each rabbit was submitted to automatic lamellar keratotomy with the automatic corneal shaper under general anesthesia. Eyes were immunosuppressed by a single local injection of methyl prednisolone. Twelve animals were inoculated into the keratomileusis interface with 1 æl of 10(6) heat-inactivated bacteria (heat-inactivated inoculum controls) and 12 with 1 æl of 10(6) live bacteria. Trimethoprim drops (0.1 percent, w/v) were used as prophylaxis for the surgical procedure every 4 h (50 æl, qid). Animals were examined by 2 observers under a slit lamp on the 1st, 3rd, 5th, 7th, 11th, 16th, and 23rd postoperative days. Slit lamp photographs were taken to document clinical signs. Animals were sacrificed when corneal disease was detected and corneal samples were taken for microbiological analysis. Eleven of 12 experimental rabbits developed corneal disease, and M. chelonae could be isolated from nine rabbits. Eleven of the 12 controls receiving a heat-inactivated inoculum did not develop corneal disease. M. chelonae was not isolated from any of the control rabbits receiving a heat-inactivated inoculum, or from the healthy cornea of control rabbits. Corneal infection by M. chelonae was successfully induced in rabbits submitted to keratomileusis. To our knowledge, this is the first animal model of M. chelonae infection following corneal flaps for refractive surgery to be described in the literature and can be used for the analysis of therapeutic responses.

Androgens and dry eye in Sjögren's syndrome.

Sjögren's syndrome is an extremely complex and currently incurable autoimmune disorder, which occurs primarily in females, and is associated with lacrimal gland inflammation, meibomian gland dysfunction, and severe dry eye. We hypothesize that androgen deficiency, which reportedly occurs in primary and secondary Sjögren's syndrome (e.g., systemic lupus erythematosus, rheumatoid arthritis), is a critical etiologic factor in the pathogenesis of dry eye syndromes. We further hypothesize that androgen treatment to the ocular surface will promote both lacrimal and meibomian gland function and alleviate both "aqueous-deficient" and "evaporative" dry eye. Our results demonstrate that androgens regulate both lacrimal and meibomian gland function, and suggest that topical androgen administration may serve as a safe and effective therapy for the treatment of dry eye in Sjögren's syndrome.

HIV-antibody detection in vitreous humor and serum by enzyme immunosorbent assay and particle agglutination test.

PURPOSE: To compare enzyme immunosorbent assay (EIA) and the particle agglutination (PA) test for the detection of antibodies to the human immunodeficiency virus (HIV) in cadaveric vitreous humor and serum. METHODS: Seventeen cadavers presenting pathologic signs of acquired immunodeficiency syndrome (AIDS) at autopsy and 33 without AIDS signs were evaluated. Consistency (k) and significance (p) between the diagnostic tests were established. RESULTS: The right and left eyes of each of 48 bilaterally tested cadavers presented identical diagnostic results in all laboratory tests. All tests were positive for antibodies in the AIDS cadavers except for two EIA-negative vitreous results. Three autopsy-negative cadavers showed by both EIA and PA testing positive results in serum and negative in vitreous. Two of them showed a serum-positive Western blot. CONCLUSION: Serum EIA anti-HIV antibody detection test is the current gold standard for evaluating corneal donor material. Neither the PA test nor EIA should be used for vitreous testing because of their low sensitivity.

Comparative influence of steroid hormones and immunosuppressive agents on autoimmune expression in lacrimal glands of a female mouse model of Sjögren's syndrome.

PURPOSE: Previous research has demonstrated that testosterone therapy causes a profound suppression of autoimmune disease in lacrimal glands of female mouse models of Sjögren's syndrome. The aim of the present study was to determine whether other anabolic androgens, nonandrogenic steroids, or immunosuppressive agents might duplicate this hormonal effect. For comparative purposes, we also evaluated the influence of these various pharmacologic compounds on the tear volume, the magnitude of lymphocyte infiltration in the submandibular gland, and the extent of mucosal and peripheral lymphadenopathy. METHODS: Female MRL/MpJ-lpr/lpr mice were administered vehicle, steroids, or immunosuppressive compounds for 21 days after the onset of disease. Lacrimal glands and tears, as well as submandibular glands, spleens, and superior cervical and mesenteric lymph nodes were collected immediately before or after treatment and then processed for analysis. RESULTS: Our results showed that: (1) the immunosuppressive impact of testosterone on lymphocyte infiltration in lacrimal tissue was reproduced by the administration of 19-nortestosterone or cyclophosphamide, but not by therapy with 17 beta-estradiol, danazol, the experimental steroid Org 4094, cyclosporine A or dexamethasone; (2) treatment with testosterone, 19-nortestosterone, cyclophosphamide, or dexamethasone significantly reduced the extent of inflammation in salivary glands; (3) exposure to cyclophosphamide markedly diminished the size of lymphatic and splenic tissues, whereas glucocorticoid treatment only decreased the weight of superior cervical lymph nodes; and (4) administration of 17 beta-estradiol, Org 4094, or dexamethasone led to a significant decrease in tear volume. CONCLUSIONS: Overall, these results demonstrate that androgen or cyclophosphamide therapy may successfully ameliorate autoimmune expression in lacrimal and salivary glands of a female mouse model of Sjögren's syndrome.

Delayed onset of varicella keratitis.

Although varicella is one of the most common infectious diseases in the United States, systemic and ocular complications are rare. We report a patient who developed disciform edema followed by microdendritic keratitis 1 and 2 months, respectively, after resolution of the acute phase of varicella. Cultures were negative, but serologic analysis found positive antibodies against varicella zoster virus and negative antibodies against herpes simplex virus. Based on this case and on a review of the literature, we believe that this delayed onset of keratitis represents a distinct category of varicella corneal complications.

Impact of androgen therapy in Sjögren's syndrome: hormonal influence on lymphocyte populations and Ia expression in lacrimal glands of MRL/Mp-lpr/lpr mice.

Recent research has demonstrated that androgen treatment dramatically curtails lymphocyte infiltration in the lacrimal glands of a mouse model of Sjögren's syndrome. The purpose of the current study was to determine whether this androgen action involves the selective suppression of specific lymphocyte populations or Ia expression in lacrimal tissue. Autoimmune female MRL/Mp-lpr/lpr mice were administered placebo- or testosterone-containing compounds for 0, 17, or 34 d. Then lacrimal glands were obtained and processed for immunohistochemical evaluation. Results demonstrated that in pretreatment mice, lacrimal lymphoid foci were composed predominantly of Thy 1.2+ cells, bearing L3T4 (helper T cell) or B220 surface antigens. In contrast, suppressor T cells (Lyt 2+) and surface IgM-bearing B cells represented minority populations in the immune infiltrates. Class II antigen (Ia) expression was observed on over 40% of the infiltrate lymphocytes and occasionally on epithelial cells close to the lymphoid focus. During the experimental time course, the extent of lymphocyte infiltration increased in glands of placebo-treated mice. This cellular accumulation was associated with an elevation in the frequency of B220+ cells, but not that of other lymphocyte subclasses. Testosterone administration induced a striking diminution in the area encompassed by all immune cell populations. Moreover, hormone therapy significantly reduced the frequency of B220+ cells in focal infiltrates. Overall, these findings demonstrate that androgen exposure stimulates a decrease in the quantity, but not necessarily the entire lymphocyte composition, of lymphoid aggregates in lacrimal glands of MRL/lpr mice.