Corneal Absorption of a New Riboflavin-Nanostructured System for Transepithelial Collagen Cross-Linking

Corneal collagen cross-linking (CXL) has been described as a promising therapy for keratoconus. According to standard CXL protocol, epithelium should be debrided before treatment to allow penetration of riboflavin into the corneal stroma. However, removal of the epithelium can increase procedure risks. In this study we aim to evaluate stromal penetration of a biocompatible riboflavin-based nanoemulsion system (riboflavin-5-phosphate and riboflavin-base) in rabbit corneas with intact epithelium. Two riboflavin nanoemulsions were developed. Transmittance and absorption coefficient were measured on corneas with intact epithelia after 30, 60, 120, 180, and 240 minutes following exposure to either the nanoemulsions or standard 0.1% or 1% riboflavin-dextran solutions. For the nanoemulsions, the epithelium was removed after measurements to assure that the riboflavin had passed through the hydrophobic epithelium and retained within the stroma. Results were compared to de-epithelialized corneas exposed to 0.1% riboflavin solution and to the same riboflavin nanoemulsions for 30 minutes (standard protocol). Mean transmittance and absorption measured in epithelialized corneas receiving the standard 0.1% riboflavin solution did not reach the levels found on the debrided corneas using the standard technique. Neither increasing the time of exposure nor the concentration of the riboflavin solution from 0.1% to 1% improved riboflavin penetration through the epithelium. When using riboflavin-5-phosphate nanoemulsion for 240 minutes, we found no difference between the mean absorption coefficients to the standard cross-linking protocol (p = 0.54). Riboflavin nanoemulsion was able to penetrate the corneal epithelium, achieving, after 240 minutes, greater stromal concentration when compared to debrided corneas with the standard protocol (p = 0.002). The riboflavin-5-phosphate nanoemulsion diffused better into the stroma than the riboflavin-base nanoemulsion. © 2013 Bottos et al.

Resolución 429(XIX): Presentación del Programa de Acción Regional al Banco Interamericano de Desarrollo (BID) = Resolution 429(XIX): Presentation of the Regional Programme of Action to the Inter-American Development Bank (BID) = Résolution 429(XIX): Soumission du Programme d'action régional à la BID

Publicado separadamete en cada idioma

Resolución 5: Préstamos del Banco Internacional = Resolution 5: Loans by the International Bank for Reconstruction and Development = Résolution 5: Prêts de la Banque Internationale pour la Reconstruction et le Développement

El símbolo E/840/Rev.1 corresponde a la edición bilingüe inglés/francés publicada en 1953

Propuesta para el establecimiento de un banco de datos estadísticos = Proposal for the establishment of a statistical data bank

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Características de un banco de datos del sector público: reflexiones sobre demandas y posibilidades

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Pautas sobre las clasificaciones estadísticas internacionales incorporadas en el banco de datos del comercio exterior de América Latina y el Caribe (BADECEL)

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Use of platelet-rich plasma in the treatment of deep corneal ulcers induced in rabbits.clinical and histomorphometric evaluation

The repair process induced corneal ulcer in rabbits using platelet-rich plasma in the form of eyedrop or clot was clinically evaluated and compared. Sixty rabbits were divided into four groups of 15 animals, denominated platelet group (PG), clot group (CLG), control group (CG), and amniotic control group (AG). Experimental groups were then subdivided into three groups (M4, M7, M30), corresponding to the end of the evaluation period. There were no differences between treatments regarding ocular sensitivity, chemosis and ocular secretion. The groups treated with PRP either as eyedrop or a clot showed less opacity than the animals treated only with amniotic membrane at the moment of the final evaluation. The presence of corneal ulcers in the groups treated with PRP showed lower intensity than the other groups. Histomorphometric examination showed that corneal epithelization in the initial phase of the lesion was greater when using PRP. The use of amniotic membrane promoted corneal epithelial and stromal thickness, as well as synergism when associated to PRP.

El Banco del Desarrollo como instrumento de financiamiento privado de la vivienda en Chile

Presenta los orígenes, objetivos, logros actuales y metas futuras del Banco del Desarrollo de Chile en sus tareas ligadas al financiamiento de viviendas.

La inversión pública en Colombia y el Banco de Proyectos de Inversión Nacional

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