Biodegradable intrascleral implant of triamcinolone acetonide in experimental uveitis.

PURPOSE: To evaluate the efficacy of a biodegradable intrascleral implant of triamcinolone acetonide (TA) in a rabbit model of experimental uveitis. METHODS: A disc-shaped TA implant (1 x 3 mm, containing 6.4 mg of TA), which is made by poly(D,L-lactide) (PLA) and TA, was intrasclerally implanted into eight albino rabbits after a subcutaneous injection of tuberculin antigen. Control animals (n = 8) received sham devices. Uveitis was induced with an intravitreal injection of tuberculin antigen. To induce chronic inflammation, all eyes were reinjected with intravitreal antigen on day 14 and were observed for 1 month. Aqueous protein concentrations and cell counts were determined on days 7, 14, and 28. Inflammation of the anterior chamber (AC) and vitreous opacity were graded clinically and retinal functions were evaluated electroretinographically and histologically. RESULTS: Anterior chamber cells, flare, and vitreous opacity scores showed significantly less inflammation in treated eyes than in untreated eyes (P < 0.05). Quantitative analyses of aqueous cell counts and protein concentrations showed significant decreases in treated eyes (P < 0.05). Histopathologic examinations showed less severe inflammation and tissue disorganization in treated eyes. CONCLUSIONS: The biodegradable intrascleral TA implant was found to be effective at suppressing the inflammation induced by experimental uveitis in rabbits for at least 4 weeks.

Antioxidant and antimelanogenic activities of polyamine conjugates from corn bran and related hydroxycinnamic acids.

The antioxidant activity of three major polyamine conjugates, N,N'-dicoumaroyl-putrescine (DCP), N-p-coumaroyl-N'-feruloylputrescine (CFP), and N,N'-diferuloyl-putrescine (DFP) isolated from corn bran, and their related hydroxycinnamic acids, p-coumaric acid and ferulic acid, were evaluated by three antioxidant in vitro assay systems, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide and hydroxyl radicals generated by enzymatic and nonenzymatic reactions. Additionally, five phenolic compounds were evaluated for melanogenesis inhibitory activity using mushroom tyrosinase and B16 melanoma cells. Most of the phenolic compounds significantly scavenged DPPH, superoxide, and hydroxyl radicals in a dose-dependent manner. Particularly, DFP showed potent DPPH (IC50 = 38.46 microM) and superoxide (IC50 = 291.62 microM) radical scavenging activities, while DCP exhibited the strongest hydroxyl radical scavenging activity (IC50 = 120.55 microM). CFP also exerted moderate DPPH, superoxide, and hydroxyl radical scavenging activities. Meanwhile, DCP (IC50 = 181.73 microM) showed potent tyrosinase inhibitory activity toward l-tyrosine as the substrate, whereas DFP (IC50 = 733.64 microM) significantly inhibited melanin synthesis in B16 melanoma cells. These current results indicate that these three polyamine conjugates from corn bran may be useful potential sources of natural antioxidants and skin-whitening agents.