Navegando por Palavras-chave "lyophilization"

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    Deep anterior lamellar transplant using lyophilized and optisol corneas in patients with keratoconus
    (Lippincott Williams & Wilkins, 2008-10-01) Farias, Roberta [UNIFESP]; Barbosa, Luciene [UNIFESP]; Lima, Acacio; Mayumi, Eliane; Lourenco, Andrea; Freitas, Denise de [UNIFESP]; Allemann, Norma; Vieira, Luis; Universidade Federal de São Paulo (UNIFESP); Sorocaba Eye Bank
    Purpose: Prospective randomized clinical trial to evaluate the efficacy of lyophilized corneas for deep anterior lamellar keratoplasty (DALK) in patients with keratoconus.Methods: Ten eyes underwent DALK and received corneas that had been lyophilized, and 10 eyes received corneas kept in Optisol. Follow-up examinations included measurement of visual acuity (VA; Early Treatment Diabetic Retiropathy Study chart), topography, pachymetry, specular microscopy, constrast sensitivity, and confocal micorscopy.Results: All vairables improved similarly in both groups, without statistical differences between them, except for the uncorrected VA in the sixth postoperative month, which was better in the lyophilized group (0.46) compared with Optisol group (0.70). the best spectacle-corrected VA was 0.16 in the lyophilized group and 0.26 in the Optisol group. the mean endothelial cell count during the sixth postoperative month was 2778.5 in the lyophilized group and 2611.5 in the Optisol group. Optisol corneas had greater keratocyte density, and the keratocyte density improved in lyophilized corneas during follow-up.Conclusion: Lyophilized corneas can be used successfully for DALK to treat keratoconus with results similar to Optisol corneas.
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    Light and Transmission Electronic Microscopy Evaluation of Lyophilized Corneas
    (Lippincott Williams & Wilkins, 2008-08-01) Farias, Roberta Jansen de Mello [UNIFESP]; Sousa, Luciene Barbosa de [UNIFESP]; Lima Filho, Acácio Alves de Souza [UNIFESP]; Lourenço, Andréia Cristina dos Santos [UNIFESP]; Tanakai, Marcia H.; Freymüller-Haapalainen, Edna [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Sorocaba Eye Bank
    Purpose: Cornea storage for longer periods is still a challenge for corneal Surgeons. The purpose of this study was to find a method to lyophilize corneas for anterior lamellar transplant and to evaluate. them by light and transmission electronic microscopy.Methods: Corneal flaps were created by using a microkeratome. Corneas were lyophilized with a cryoprotectant (2.3 mol sacarousis for 40 minutes) and without a cryoprotectant in a lyophilization machine (Modulyon D). The corneas were rehydrated with distilled water, balanced saline solution (BSS), and phosphate-buffered saline, after which they were evaluated by microscopy. A cornea that did not undergo lyophilization served as a control.Results: Lyophilization without a cryoprotectant did not preserve the corneal structure. This finding was also observed when lyophilizing and rehydrating the corneas with distilled water or phosphate-buffered saline. We found that lyophilizing corneas and rehydrating them with 11 mL of BSS for 30 minutes preserved the general corneal structure, the parallelism of the collagen fibers, the Bowman layer, and the epithelial basement membrane for 15 and 30 days and for as long as 1 year or more.Conclusions: Lyophilization with sacarousis and rehydration with BSS may be a good method for anterior lamellar transplantation.