Effects of various lubricants on corneal surface regularity in rabbits.

The aim of this study was to establish a method for analysis of tear film stability and thereby to investigate the effects of lubricants on corneal surface regularity and corneal epithelial damage in anesthetized rabbits with the eye held open. Saline-instilled and noninstilled eyes manifested a time-dependent increase in the corneal surface regularity index (SRI). In contrast, 0.1% hyaluronic acid (HA) prevented the increase in the SRI for up to 20 min after instillation. Methylene blue uptake into the damaged cornea was significantly greater in eyes that received saline than in those treated with HA. Whereas eyes instilled with 0.5% methylcellulose (MC) or 0.35% sodium carboxymethylcellulose (CMC) manifested an increase in the SRI similar to that apparent in those that received saline, 1.0% chondroitin sulfate (CS) prevented the increase in the SRI for up to 10 min after instillation. In conclusion, we have established a method for analysis of tear film stability in rabbits. Our results suggest that tear film stability is closely related to corneal surface damage and that topical instillation of 0.1% HA or 1.0% chondroitin sulfate warrants further investigation as a potential treatment for patients with dry eye.

Efficacy of atovaquone against Babesia gibsoni in vivo and in vitro.

The therapeutic efficacy of atovaquone against Babesia gibsoni was examined in three dogs experimentally infected with B. gibsoni isolated from naturally infected dogs in Aomori Prefecture, Japan. Once parasitemia reached 10%, atovaquone was administered orally (30 mg/kg twice daily for 7 days). Within 2 days of atovaquone treatment, the parasite disappeared from blood smears without any clinical side effects. Anemia and thrombocytopenia were significantly improved in all the dogs. However, a polymerase chain reaction assay revealed that a B. gibsoni marker gene was intermittently present in peripheral blood after atovaquone therapy, indicating that the organism had not been eliminated, and parasites reappeared in blood smears 33 days after the last treatment. To investigate the change in sensitivity against atovaquone, an in vitro sensitivity test was performed using peripheral blood obtained from an untreated dog that was infected with the original parasite isolate, and from two of the experimentally infected and atovaquone-treated animals (blood was collected at the time of the post-treatment recurrence of the B. gibsoni infection). Atovaquone was added to the culture medium to final concentrations of 0.1, 1, 10, 100, and 1000 nM. For the untreated parasites, complete growth inhibition occurred at 1000 nM of atovaquone, whereas the recurrent parasites were inhibited by only 39.52 +/- 8.34% and 31.31 +/- 8.14% at this concentration after 48 h of incubation. Thus, the recurring parasites were less sensitive to atovaquone than the untreated originally isolated parasites.

Restoration of corneal epithelial barrier function and wound healing by substance P and IGF-1 in rats with capsaicin-induced neurotrophic keratopathy.

PURPOSE: To investigate the effects of topical application of the combination of substance P (SP) and insulin-like growth factor (IGF)-1 on corneal epithelial barrier function and epithelial wound closure in rats with capsaicin-induced neurotrophic keratopathy. METHODS: Neonatal rats were injected subcutaneously with a single dose of capsaicin to induce neurotrophic keratopathy. Corneal epithelial barrier function was evaluated with an anterior fluorophotometer. Tear fluid secretion was measured by the Schirmer test. Corneal epithelial wound healing was determined by measurement of the size of the epithelial defect after debridement of the entire epithelium. The combination of SP (1 mM) and IGF-1 (1 micro g/mL) in phosphate-buffered saline was administered in eye drops six times daily. RESULTS: Corneal epithelial barrier function was impaired and corneal epithelial wound healing was delayed in rats injected with capsaicin. The application of eye drops containing the combination of SP and IGF-1 to capsaicin-injected rats resulted in a significant improvement in corneal epithelial barrier function compared with that apparent in capsaicin-injected animals that received eye drops containing vehicle alone. Such treatment with SP and IGF-1 also significantly increased the rate of corneal epithelial wound closure in capsaicin-injected animals. CONCLUSIONS: Topical application of the combination of SP and IGF-1 improved both corneal epithelial barrier function and epithelial wound healing in an animal model of neurotrophic keratopathy.