S U M M A R YThis study localized malondialdehyde (MDA, a toxic byproduct of lipid peroxidation), nitrotyrosine [NT, a cytotoxic byproduct of nitric oxide (NO)], and nitric oxide synthase isomers (NOS) in normal and diseased human corneas. Normal corneas ( n ϭ 11) and those with clinical and histopathological diagnoses of keratoconus ( n ϭ 26), bullous keratopathy ( n ϭ 17), and Fuchs' endothelial dystrophy ( n ϭ 12) were examined with antibodies specific for MDA, NT, eNOS (constitutive NOS), and iNOS (inducible NOS). Normal corneas showed little or no staining for MDA, NT, or iNOS, whereas eNOS was detected in the epithelium and endothelium. MDA was present in all disease groups, with each group displaying a distinct pattern of staining. NT was detected in all keratoconus and approximately one half of Fuchs' dystrophy corneas. iNOS and eNOS were evident in all the diseased corneas. Keratoconus corneas showed evidence of oxidative damage from cytotoxic byproducts generated by lipid peroxidation and the NO pathway. Bullous keratopathy corneas displayed byproducts of lipid peroxidation but not peroxynitrite (MDA but not NT). Conversely, Fuchs' dystrophy corneas displayed byproducts of peroxynitrite with little lipid peroxidation (NT ϾϾ MDA). These data suggest that oxidative damage occurs within each group of diseased corneas. However, each disease exhibits a distinctive profile, with only keratoconus showing prominent staining for both nitrotyrosine and MDA. These results suggest that keratoconus corneas do not process reactive oxygen species in a normal manner, which may play a major role in the pathogenesis of this disease.

Diabetic retinopathy remains the leading vascular-associated cause of blindness throughout the world. Its treatment requires a multidisciplinary interventional approach at both systemic and local levels. Current management includes laser photocoagulation, intravitreal steroids, and anti-vascular endothelial growth factor (VEGF) treatment along with systemic blood sugar control. Anti-VEGF therapies, which are less destructive and safer than laser treatments, are being explored as primary therapy for the management of vision-threatening complications of diabetic retinopathy such as diabetic macular edema (DME). This review provides comprehensive information related to VEGF and describes its role in the pathogenesis of diabetic retinopathy, and in addition, examines the mechanisms of action for different antiangiogenic agents in relation to the management of this disease. Medline (Pubmed) searches were carried out with keywords “VEGF”, “diabetic retinopathy”, and “diabetes” without any year limitation to review relevant manuscripts used for this article.

A flexible chemistry for solid phase attachment of oligonucleotides is described. Oligonucleotides bearing 5'-terminal acrylamide modifications efficiently co-polymerize with acrylamide monomers to form thermally stable DNA-containing polyacrylamide co-polymers. Co-polymerization attachment is specific for the terminal acrylamide group. Stable probe-containing layers are easily fabricated on supports bearing exposed acrylic groups, including plastic microtiter plates and silanized glass. Attachment can be accomplished using standard polyacrylamide gel recipes and polymerization techniques. Supports having a high surface density of hybridizable oligonucleotide (approximately 200 fmol/mm2) can be produced.

PURPOSE.To determine whether keratoconus (KC) corneal fibroblast cultures have increased reactive oxygen species (ROS) production and are more susceptible to stress-related challenges. METHODS. Normal (n ϭ 9) and KC (n ϭ 10) stromal fibroblast cultures were incubated in either neutral-or low-pH conditions, with or without hydrogen peroxide. Catalase activities were measured with a fluorescent substrate assay. Superoxide and ROS/reactive nitrogen species (RNS) productions were determined with an amine-reactive green-dye assay and 2Ј,7Ј-dichlorodihydrofluorescein diacetate (H 2 DCFDA) dye assay, respectively. Cell viability was analyzed by a dye-exclusion assay. Caspase 3 activity was measured by a fluorochrome inhibitor of caspase (FLICA) assay. A cationic (green) dye was used to measure the mitochondrial membrane potential (⌬⌿m). RESULTS. KC fibroblasts had increased superoxide and ROS/RNS production (6.2-fold, P Ͻ 0.001 and 1.8-fold, P Ͻ 0.001, respectively) and catalase activity (P Ͻ 0.01) with higher concentrations of H 2 O 2 compared with normal cultures (P ϭ 0.16). After a low-pH stress challenge, KC fibroblasts maintained higher ROS/RNS levels (3.3-fold, P Ͻ 0.02), showed higher caspase-3 activity (7.5-fold, P Ͻ 0.02) and decreased ⌬⌿m (2.6-fold, P Ͻ 0.04), and had decreased cell viability (37%, P Ͻ 0.005 vs. 20%, P Ͻ 0.27) compared with normal fibroblasts. CONCLUSIONS. Under identical conditions, KC fibroblasts had increased basal generation of ROS/RNS and were more susceptible to stressful challenges (low-pH and/or H 2 O 2 conditions) than were normal fibroblasts. In addition, the stressed KC fibroblasts possessed characteristics similar to those found in the intact KC corneas (increased catalase activity, ROS production, and apoptosis). These properties may play a role in the pathogenesis of KC. (Invest Ophthalmol Vis Sci.