Effects of intravitreal triamcinolone acetonide injection with and without preservative

Universidade Federal de São Paulo, Dept Ophthalmol, Vis Inst, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Ophthalmol, Vis Inst, BR-04023062 São Paulo, BrazilWeb of Scienc

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

Photograph of corneal buttons of rabbit eyes soaked with riboflavin-5-phosphate nanoemulsion or standard 0.1% riboflavin.

<p>Cornea with intact epithelium after exposure to 0.5% riboflavin-5-phosphate nanoemulsion for 240 minutes (A). Cornea with intact epithelium after exposure to the standard 0.1% riboflavin solution for 240 minutes (B). De-epithelialized cornea exposed to 0.1% riboflavin solution for 30 minutes - standard technique (C).</p

Absorption spectra of riboflavin-5-phosphate nanoemulsion and riboflavin-base nanoemulsion.

<p>Absorption spectra of riboflavin-5-phosphate nanoemulsion and riboflavin-base nanoemulsion.</p

Photograph of the corneal buttons of rabbit eyes of after exposure to different riboflavins.

<p>Corneas with intact epithelium (A, B, and C) after exposure to 0.1% riboflavin-dextran solution for 30 minutes (A) and for 240 minutes (B), as well as after exposure to concentrated 1% riboflavin-dextran for 240 minutes (C). De-epithelialized cornea soaked with 0.1% riboflavin-dextran for 30 minutes - standard technique (D). The yellow staining shows that riboflavin diffused into the stroma only when the epithelium was removed.</p

Change of transmittance and absorption coefficient of rabbit corneas in the course of time.

<p>Transmittance change (A) and absorption coefficient change (B) of corneas soaked with riboflavin formulations. Dashed lines show group I values (standard treatment).</p

Stability evaluation of the nanoemulsions over time.

<p>Key: (□) Unloaded nanoemulsion (R = 0.9965); (○) Riboflavin-5-loaded nanoemulsion (R = 0.9927). Mean of 10 analytical determinations ± standart deviation.</p

Cirurgia de revascularização do miocárdio através de minitoracotomia ântero-lateral esquerda Myocardial revascularization surgery through left anterolateral minithoracotomy

No período de outubro de 1995 a fevereiro de 1996, 16 pacientes selecionados foram submetidos a cirurgia de revascularização do miocárdio através de minitoracotomia ântero-lateral esquerda. Em todos os casos a artéria torácica interna esquerda foi dissecada, para posterior anastomose com o ramo interventricular anterior (RIA) sem a utilização de circulação extracorpórea. A idade variou de 43 a 77, com média de 60 anos. Sessenta e dois por cento dos pacientes eram do sexo masculino. Não houve complicações tais como: hemorragias, acidente vascular cerebral, insuficiência renal aguda, mediastinite ou infarto agudo do miocárdio. Não houve mortalidade no grupo em questão. Em 4 (25%) pacientes foi realizado estudo hemodinâmico, que demostrou uma normalidade da anastomose da artéria torácica interna para o ramo interventricular anterior. Devido aos excelentes resultados iniciais, acreditamos que este procedimento possa ser empregado com maior freqüência e com a familiarização dos grupos cirúrgicos, e que as artérias diagonais e marginais da circunflexa possam ser beneficiadas com este tipo de procedimento.<br>Between October 1995 and February 1996, sixteen patients were selected to undergo to surgical myocardial revascularization through left anterolateral minithoracotomy. The left internal thoracic artery was dissected in all patients, for consecutive anastomosis with interventricular anterior artery, without using extracorporeal circulation. Patients age ranged from 43 to 77, average 60 years. Sixty-two percent of them were men. There were no complications such as: acute myocardial infarction, mediastinitis, acute renal failure, hemorrhagy or stroke. There were no deaths. Four (25%) patients were submitted to cardiac catheterization that showed patency of grafts and grafted native arteries. Due to excellent initial results, the authors believe that this technique can be employed with greater frequency and that its use can be extended to the treatment of diagonal branches of the interventricular anterior artery and marginal branches of the circunflex, as soon as the surgical teams become more familiarized with it