Systemic and ocular antibody responses to inactivated acute hemorrhagic conjunctivitis (AHC) virus; enterovirus 70 (EV70)

PURPOSE

Evaluate the immune response in rabbits injected with EV70, the agent of acute hemorrhagic conjunctivitis (AHC) and AHC associated neuropathy.

METHODS

Rabbits were injected intramuscularly with uv-light inactivated EV70 isolate J670/71. Neutralizing activity against EV70 was quantified in serum and tear samples and the immunoglobulin (Ig) classes of the neutralizing activity in serum identified by sucrose gradient ultra-centrifugation. Adjuvant muramyl dipeptide (MDP) was applied topically to assess the role of ocular inflammation on levels of neutralizing antibody, proteins and Ig in tears. The protective effects of human and rabbit sera and interferon-alpha (IFN-alpha) against EV70 were compared in human conjunctival and lens cells.

RESULTS

Sera collected at 6 and 13 d contained 19S IgM anti-EV70 neutralizing antibody, while serum collected 21 d post injection contained 19S IgM and 7S IgG anti-EV70 neutralizing antibody. Low titers of anti-EV70 activity (< or =30 U/ml) were detected in tears of seropositive rabbits. MDP induction of conjunctivitis in seropositive rabbits increased tear IgG concentration (3-fold) and anti-EV70 neutralizing antibody titers (> or =10-fold). The protective effect of the rabbit and human sera against EV70 infection in conjunctival, but not lens epithelial cells, was enhanced by the addition of IFN-alpha.

CONCLUSIONS

Immunization with uv-light inactivated EV70 elicits a classical humoral immune response in rabbits. The protective activity of serum in EV70-infected human conjunctival cells, but not lens cells, was increased by IFN-alpha. Adjuvant MDP-induced conjunctivitis, increased blood-conjunctival barrier (BCB) permeability and anti-EV70 neutralizing activity in tear of seropositive rabbits. The results suggest immunization with inactivated EV70 could provide systemic as well as ocular protection during natural EV70 infection.

A randomized study of dorzolamide in the prevention of elevated intraocular pressure after anterior segment laser surgery. Dorzolamide Laser Study Group

PURPOSE

To evaluate the efficacy of 2% dorzolamide hydrochloride opthalmic solution in preventing spikes in intraocular pressure (IOP) after anterior segment laser surgery.

METHODS

This 24-hour, placebo-controlled, randomized, double-masked, multicenter evaluation was conducted to determine the efficacy of dorzolamide hydrochloride 2% in controlling IOP after neodimium:yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy, argon laser trabeculoplasty, or laser iridotomy. The 122 patients enrolled were assigned in randomized fashion to receive dorzolamide or placebo 1 hour before and immediately after the procedure; IOP was measured 1, 2, 3, 4, and 24 hours after the procedure.

RESULTS

Of 61 patients receiving dorzolamide, only one (1.7%) had a spike in IOP of 10 mmHg or more, compared with 9 (14.8%) of the 61 patients receiving placebo. Mean IOP among patients receiving dorzolamide was significantly reduced both from baseline and compared with that among patients receiving placebo from 1 to 4 hours after administration. Only 5 (8%) of the 61 patients receiving dorzolamide experienced at least one adverse event, compared with 15 (25%) of the 61 patients receiving placebo.

CONCLUSION

Dorzolamide was effective in preventing spikes in IOP after anterior segment laser surgery. Dorzolamide was generally well tolerated after short-term use.

A natural history study of experimental Staphylococcus epidermidis endophthalmitis

The purpose of this study was to find a "threshold" quantity of organisms (i.e. inoculum) to produce clinical endophthalmitis and determine the natural course of intravitreal bacterial counts following inoculation in a rabbit model of Staphylococcus epidermidis endophthalmitis. S. epidermidis endophthalmitis was induced experimentally in 18 New Zealand white rabbits. Eyes were injected with 2.0 x 10(3) (Group I: n = 3), 2.0 x 10(4) (Group II: n = 3), 3.0 x 10(5) (Group III: n = 3), 3.0 x 10(6) (Group IV: n = 3), 3.0 x 10(7) (Group V: n = 3), or 3.0 x 10(8) (Group VI: n = 3) organisms. Serial quantitative bacterial cultures (colony counts) were performed on the vitreous every eight hours for 9 days. All eyes in Groups I and II became culture negative by 24-64 hours post-inoculation (PI). All eyes in Groups III-VI remained culture positive [approximately 600-4000 colony forming units (CFU) per cm3] at 48 to 72 hours PI and were stable for the remainder of the nine day study period. Previous work suggests that the host's inflammatory response is more important than had been recognized. Previous rabbit models of infectious endophthalmitis are known to become culture negative ("autosterilized") despite continued intraocular inflammation. This rabbit model demonstrates a "threshold" of infection where the host's immune response is overwhelmed and "autosterilization" does not occur. When inoculated with 3.0 x 10(5) or greater S. epidermidis organisms of this strain, continued active bacterial replication can now be studied in the rabbit.