Rabbit model of retinoblastoma.

We created a rabbit model of retinoblastoma and confirmed the tumor clinically and histopathologically. Seventeen New Zealand rabbits were immunosuppressed with cyclosporin A at doses of 10-15 mg/kg. At day 3, the animals received a 30 µl subretinal injection of 1 x 106 cultured WERI retinoblastoma cells. Digital fundus images were captured before euthanasia, and the eyes were submitted for histopathology. Retinoblastoma cells grew in all the inoculated eyes and established a tumor under the retina and/or in the vitreous. New blood vessels in the tumor were observed starting at week 5. Cuffs of viable tumor cells surrounded the blood vessels with regions of necrosis present at 70-80 µm from nutrient vessels. Occasional tumor seeds in the vitreous histologically exhibited central necrosis. This rabbit model demonstrated similar fundus appearance and pathologic features to human retinoblastoma and may be used as a model to test various routes of drug delivery for retinoblastoma.

Deposits of transforming growth factor-beta-induced protein in granular corneal dystrophy type II after LASIK.

PURPOSE: To analyze components of the deposits in the corneal flap interface of granular corneal dystrophy type II (GCD II) patients after laser in situ keratomileusis (LASIK). METHODS: Four corneal GCD II specimens displaying disease exacerbation after LASIK were analyzed. Three of these specimens included the recipient corneal button after penetrating keratoplasty or deep lamellar keratoplasty for advanced GCD II after LASIK. The fourth specimen, a similar case of GCD II after LASIK, included the amputated corneal flap. Specimens were processed for histopathologic and immunohistochemical analyses. RESULTS: Corneal stromal deposits in the LASIK flaps of all specimens were stained with 3 anti-transforming growth factor-beta-induced protein (TGFBIp) antibodies. The deposits displayed bright red color staining with Masson trichrome; however, negative staining was seen with Congo red, suggesting that hyaline is the main component localizing to the TGFBIp deposits rather than amyloid. CONCLUSIONS: Amorphous granular material deposited along the interface of the LASIK flap in GCD II corneas is composed mainly of hyaline deposits.

Avellino corneal dystrophy exacerbated after LASIK: scanning electron microscopic findings.

PURPOSE: To evaluate the ultrastructure of the cornea of Avellino corneal dystrophy (ACD) exacerbated by LASIK. METHODS: Three ACD patients with exacerbation of granular corneal deposits after LASIK underwent surgical removal of the corneal flap. The corneal flap was processed for scanning electron microscopy (SEM). RESULTS: SEM of all patients showed abnormal granular clusters in the fibrils of the corneal flap. CONCLUSION: Laser in situ keratomileusis induces corneal collagen abnormalities and adhesions of granular material in ACD patients.

Effect of intravitreal bevacizumab on vascular endothelial growth factor expression in patients with proliferative diabetic retinopathy.

PURPOSE: To investigate the effect of bevacizumab (Avastin; Genentech, San Francisco, CA, USA) on vascular endothelial growth factor (VEGF) expression and inflammation in fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR). MATERIALS AND METHODS: Fibrovascular membranes from 19 eyes of 18 patients with PDR were studied using immunohistochemistry and analyzed in the following 3 groups; group 1: 4 inactive PDR eyes, group 2: 10 active PDR eyes treated preoperatively with adjunctive intravitreal bevacizumab, group 3: five active PDR eyes not treated preoperatively with bevacizumab. Immunohistochemical staining for VEGF, CD31 and CD68 were done. RESULTS: The immunoreactivity to VEGF and CD 31-positive blood vessels was significantly higher in membranes from group 3 than group 1 (p = 0.007 for VEGF, 0.013 for CD 31-positive vessels). Intravitreal bevacizumab caused a reduction in VEGF expression and vascular densities in 4 out of 10 (40%) excised membranes from eyes with PDR. However, six membranes (60%) in group 2 still demonstrated relatively strong VEGF expression and high vascular density. Infiltration of macrophages was observed in 16 out of the 19 membranes, and the density of macrophages was increased in group 2 compared with group 1 (p = 0.043). CONCLUSION: Intravitreal bevacizumab injections caused some reduction in VEGF expression and vascular densities in a limited number of active PDR patients. A single intravitreal bevacizumab injection may not be enough to induce complete blockage of VEGF and pathologic neovascularization in active PDR patients. Repeated injections, panretinal photocoagulation and/or PPV may be necessary following intravitreal bevacizumab to reinforce the anti-VEGF effect of the drug.

Donor corneas misidentified with prior laser in situ keratomileusis.

PURPOSE: To evaluate the rate of donor corneas misidentified as recipients of previous laser in situ keratomileusis (LASIK) surgery in the eye banks. METHODS: One hundred sixty-one donor corneas identified as having had previous LASIK surgery from 15 eye banks were sent to the Emory Eye Center between January 2002 and August 2005. Determination of the previous LASIK surgery was made from the medical history and/or slit-lamp examination in the contributing eye bank. Histologic examination of the corneas was performed to confirm the diagnosis. RESULTS: Information regarding the decision making was available in 155 corneas out of 161. Among 155 corneas, 16 donor corneas (10.3%) revealed no evidence of previous LASIK surgery in the histology. The rate of misidentified corneas as having previous LASIK was 13.5% in history only group (10 of 74) and 18.2% in those determined by the slit-lamp examination only (4 of 22). In corneas determined by both history and slit-lamp examination, the misidentified rate decreased to 3.4% (2 of 59). CONCLUSIONS: There is approximately a 10% rate of misidentified post-LASIK corneas in eye banks. A decision made by both history and slit-lamp examination decreases the misidentification rate compared with using only either method alone.