The Effect of Sildenafil on Selenite-Induced Cataract in Rats.

PURPOSE: To investigate the effect of sildenafil on an experimental sodium selenite-induced cataract model in rats. MATERIALS AND METHODS: Twenty-six young Wistar rats were separated into four groups. On postpartum day 10, six rats received only selenite (group 1, selenite-induced cataract), seven rats received selenite and high dose oral sildenafil (group 2, high-dose sildenafil-treated), seven rats received selenite and low dose oral sildenafil (group 3, low-dose sildenafil-treated), and six rats received only saline (group 4, controls). On postpartum day 30, cataract formation was graded and recorded using an operating microscope. The rats were sacrificed, lens tissues were isolated, and serum samples were collected. Nitrite oxide metabolites (NOx), advanced oxidative protein products (AOPP), and total sulfhydryl (TSH) levels were assessed in both serum and lenticular samples. RESULTS: The rats treated with low-dose sildenafil showed lower levels of AOPP and NOx, and the higher levels of TSH than the rats in other experimental groups. Otherwise, the rats treated with high-dose sildenafil, similar to the selenite-induced cataract group, showed higher levels of AOPP and serum NOx than rats in the low-dose sildenafil-treated group. The rats treated with low-dose sildenafil also showed less cataract development than rats in the other experimental groups. CONCLUSION: Low doses (0.7 mg/kg) of oral sildenafil might show a protective effect on cataract development by lowering oxidative stress.

Rose Bengal-Mediated Photodynamic Antimicrobial Treatment of Acanthamoeba Keratitis.

Purpose: To evaluate the in vivo efficacy of rose bengal (RB)-mediated photodynamic antimicrobial therapy (PDAT) for treatment of Acanthamoeba castellanii keratitis (AK). Materials and Methods: An animal (rabbit) AK model was successfully achieved via intrastromal inoculation of a suspension of A. castellanii cells and trophozoites. Prior to RB-PDAT (pre-treatment, day-5), the severity of the induced corneal infection was graded numerically for epithelial defects, stromal edema, neovascularity, and stromal opacity/infiltration. The right eyes of rabbits (n = 18) were divided equally into three groups (n = 6/group): control (no treatment); 0.1% RB+518 nm irradiation (5.4 J/cm2); and 0.2% RB+518 nm irradiation (5.4 J/cm2). On post-treatment day-5, animals were euthanized, after which corneal buttons were excised and submitted for real-time polymerase chain reaction (RT-PCR) analysis. Results: Post-treatment clinical scores of the 0.1 and 0.2% RB groups indicated significant improvement compared to control group scores (pre-treatment clinical scores; 5.17 ± 0.98, 7.50 ± 0.62, and 6.17 ± 0.70 and post-treatment clinical scores; 4.50 ± 0.56, (p = .043), 3.50 ± 0.99 (p = .039), 6.83 ± 1.66 (p = .34), respectively). RT-PCR analysis revealed that the mean cycle threshold (Ct) values were significantly higher in treated-group corneas compared to control-group corneas, with no significant differences between treated-groups (Mean Ct values; 34.33, 34.5, and 29.67 for 0.1 and 0.2% RB, and control groups). There was a statistically significant negative correlation between post-treatment clinical scores and Ct values (r = -0.474, p-value 0.047). Conclusions: Our results demonstrate that RB-PDAT is effective in decreasing the parasitic load and clinical severity of AK.

Uveal melanoma in children and teenagers.

PURPOSE: To review the features and prognosis of uveal melanoma in children. METHODS: Retrospective case series. RESULTS: Of 122 children with uveal melanoma, there were 53 (43%) male and 69 (57%) female patients. In this group, the mean age at presentation was 15 years (median 16 years, range 3-20 years). Age at presentation was 0 to 5 years in 4 (3%), 5.1 to 10 years in 14 (11%), 10.1 to 15 years in 43 (35%), and 15.1 to ⩽20 in 61 (50%). Associated ocular melanocytosis was present in 4 (3%). The melanoma was primarily located in the iris (n = 30, 25%), ciliary body (n = 10, 8%), or choroid (n = 82, 67%). The mean tumor basal dimension was 9.8 mm and mean thickness was 5.0 mm. The tumor color was pigmented (brown) (n = 102, 84%), nonpigmented (yellow) (n = 19, 16%), or mixed (n = 25, 21%). Subretinal fluid (n = 66, 54%) and hemorrhage (n = 9, 7%) were noted. Primary treatment involved laser photocoagulation (n = 3, 2%), transpupillary thermotherapy (n = 17, 14%), local tumor resection (n = 26, 21%), plaque radiotherapy (n = 42, 34%), or enucleation (n = 54, 44%). Kaplan Meier 5, 10, and 20-year estimates for uveal melanoma-related metastasis were 9%, 9%, and 20%, respectively, for children compared to 15%, 25%, and 36% for all ages. CONCLUSION: Uveal melanoma in children tends to occur most often in the teenage years as a pigmented tumor involving the choroid or iris and with mean thickness of 5 mm. Prompt treatment is advised.