Identification of protein-protein interaction inhibitors targeting vaccinia virus processivity factor for development of antiviral agents.

Poxvirus uracil DNA glycosylase D4 in association with A20 and the catalytic subunit of DNA polymerase forms the processive polymerase complex. The binding of D4 and A20 is essential for processive polymerase activity. Using an AlphaScreen assay, we identified compounds that inhibit protein-protein interactions between D4 and A20. Effective interaction inhibitors exhibited both antiviral activity and binding to D4. These results suggest that novel antiviral agents that target the protein-protein interactions between D4 and A20 can be developed for the treatment of infections with poxviruses, including smallpox.

L-arginine-threonine-arginine (RTR) tetramer peptide inhibits ulceration in the alkali-injured rabbit cornea.

PURPOSE: Proline-glycine-proline (PGP) peptides have been identified as inflammatory mediators initiating neutrophil invasion into alkali-injured cornea. The complementary peptide, arginine-threonine-arginine (RTR), has been shown to bind to the PGP sequence and impede neutrophil infiltration. A prior study showed that L-RTR tetramer and D-RTR tetramer, used alternately (14 times a day), resulted in significantly reduced incidences of corneal ulceration and severity. The purpose of this experiment is to determine the effectiveness of both tetramers, used separately, compared with control. METHODS: Rabbit corneas were exposed to 1 N NaOH for 35 seconds. Sixteen animals were randomly assigned to each of 3 groups: 1) phosphate-buffered saline (PBS), 2) 1.5 mM L-RTR, or 3) 800 microM D-RTR. One drop of each was administered hourly (14 times a day) for 36 days. Additional studies were done to assess neutrophil infiltration into corneas with and without RTR treatment. RESULTS: The severity of corneal ulceration in both RTR groups was statistically significantly different from the 21st day of the experiment to the end. As a result of ulcers healing in the L-RTR group, there was a statistically significant reduction in the number of ulcers beginning on day 22 versus control. Although there was healing in the D-RTR group, the incidence of ulcers was not significantly different from control or L-RTR. Morphometric analysis revealed decreased neutrophil (PMN) invasion with RTR treatment compared with PBS control. CONCLUSIONS: Binding of the PGP molecules by RTR tetramer seems to deprive the cornea of this neutrophilic chemotactic stimulus, leading to a reduction in the severity and incidence of corneal ulceration.

Fibrin sealant in corneal stem cell transplantation.

PURPOSE: To determine if transplanted corneal epithelial stem cells are safely and efficiently attached to the deficient limbal niche with use of fibrin sealant. The primary outcome is measured with respect to the stability of the transplant, with secondary qualitative evaluations of inflammation, patient comfort, speed of operation, and incidence of complications. METHODS: This retrospective case study examined a total of 114 corneal stem cell reconstructions performed in 95 patients from 1996 to 2004 using corneal stem cells primarily, with a minority of amnion alone, or both. Fibrin sealant was used as the only technique of stem cell adhesion for limbal reconstruction for primary or recurrent pterygia and various stem cell-deficient diseases from 2000 to 2004. RESULTS: The fibrin sealant group showed 1 small recurrence of pterygium but no complications. With sutures, there were 3 recurrences in the pterygia group. After completion of all surgical procedures, all patients were free of pterygia. Miscellaneous stem cell deficiencies were included to demonstrate that corneal stem cell transplants can be used in other corneal procedures in addition to pterygia. CONCLUSIONS: Fibrin sealant alone effectively and safely attached corneal stem cell transplants to the limbal niche. The additional qualitative observations of a reduction in operation time, postoperative pain, and inflammation augurs for more extensive use of fibrin sealants in ophthalmology.