Intraocular pressure response to the replacement of pilocarpine or carbachol with echothiophate.

In 20 patients with open-angle glaucoma in aphakia or pseudophakia whose intraocular pressure had remained uncontrolled on their current medical therapy, the medication was changed from pilocarpine or carbachol to echothiophate iodide. In all, 12 patients (60%) showed a statistically significant improvement in pressure control, 7 (35%) showed no change, and 1 had higher pressure. One-third of the patients with improved intraocular-pressure control eventually required laser or incisional surgery after a mean of 23 months, whereas the remaining subjects were controlled for the duration of the follow-up, which averaged 26 months. Side effects encountered during echothiophate iodide treatment included ocular irritation, decreased vision, and one retinal detachment.

Adherence properties of Pseudomonas pili to epithelial cells of the human cornea.

In vitro adherence of Pseudomonas fluorescens organisms to the human cornea is correlated with bacterial pili. The role of pili in the attachment to human corneal epithelial cells was studied in an in vitro adherence assay system. A homogeneous, purified pilin preparation showed a molecular weight of 16,500 on SDS-polyacrylamide gels. Within 5 minutes incubation, 5.5 pg of pilin adhere to 15,000 epithelial cells. When epithelial cells were preincubated with purified pilin, a subsequent decrease in adherence of labeled pilin was noted. It appears that pili mediate adherence of Pseudomonas organism to human cornea.

Herpetic keratitis in athymic (nude) mice.

The inflammatory response to herpes simplex virus infection of the cornea was studied in athymic nude (nu/nu) and heterozygote (nu/+) BALB/c mice. Although athymic mice were highly susceptible to HSV infection and died 13 to 17 days after corneal inoculation, they failed to develop necrotizing keratitis of the cornea. Heterozygote mice survived the initial virual infection, but many of these mice developed necrotizing keratitis and permanent corneal scarring. Light and electron microscopy showed numerous inflammatory cells (polymorphonuclear leukocytes and lymphocytes) in the corneas of heterozygote mice, but not in the athymic mice. These studies suggest that the immune system plays a dual role in herpes simplex virus infection of the cornea: protection against dissemination of the virus and immunopathogenesis of necrotizing keratitis in the cornea.

Histological and electron microscopic studies of experimental herpetic keratitis in the rabbit.

Histological and electron microscopic observations, together with virus cultures, were made in the eyes of 50 New Zealand white rabbits which received bilateral intrastromal inoculation with the RE strain of herpes simplex virus. Virus cultures of whole corneas were positive for the first 2 weeks following inoculation, but were consisently negative thereafter. An inflammatory response to HSV infection, consisting of polymorphonuclear leukocytes and lymphocytes, was seen in the limbus within 7 hours after inoculation of the cornea. A massive accumulation of lymphocytes and plasma cells appeared in the limbus, suggesting that the limbus may behave as a lymphoid tissue, where differentiation and maturation of lymphoid cells occur as they acquire immunocompetence. Neovascularization of the cornea was associated with a heavy infiltration of the surrounding stroma with polymorphonuclear leukocytes, as well as numerous plasma cells and a few lymphocytes and macrophages. Numerous abnormal, pleomorphic keratocytes were found in the stroma. Lymphocytes were frequently found closely adhering to these abnormal keratocytes, suggesting a T-cell attack on a target cell. A model which describes the mechanism by which herpes virus infection leads to corneal scarring is suggested.