HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kayatz, P. Articles by Schraermeyer, U. Search for Related Content PubMed PubMed Citation Articles by Kayatz, P. Articles by Schraermeyer, U.

Oxidation Causes Melanin Fluorescence

From the Department of Vitreoretinal Surgery, Division of Ophthalmology, University of Cologne, Germany.

PURPOSE. The goal of this study is the characterization of the strong yellow fluorescence of oxidized melanin in the retinal pigment epithelium (RPE) and the choroid.

METHODS. Naturally occurring melanin in the human retina and choroid was oxidized by exposing fixed and plastic-embedded sections of a human eye to light and hydrogen peroxide. Synthetic melanin was also oxidized in vitro by exposure to light and hydrogen peroxide. The fluorescence of oxidized melanin was examined by absorption spectroscopy, fluorescence spectroscopy, and fluorescence microscopy.

RESULTS. Naturally occurring melanin oxidized in situ exhibited a lipofuscin-like yellow fluorescence. Oxidation of melanin in vitro degraded the melanin polymer, resulting in a fluorescent solution. Fluorescence spectroscopy gave an excitation maximum at approximately 470 nm and an emission maximum at approximately 540 nm for both natural and synthetic melanin. Increasing the time of exposure to light or hydrogen peroxide increased melanin fluorescence.

CONCLUSIONS. The results indicate that the strong yellow fluorescence of melanin in the RPE and choroid in situ is a property of oxidized melanin and is not due to contamination of the melanin by proteinaceous or lipid materials. The data presented allow a reinterpretation of the results obtained from fluorescence investigations of melanin-containing tissue and suggest a link between melanin degradation and lipofuscin formation.

This article has been cited by other articles:

				B. Rozanowski, J. M. Burke, M. E. Boulton, T. Sarna, and M. Rozanowska Human RPE Melanosomes Protect from Photosensitized and Iron-Mediated Oxidation but Become Pro-oxidant in the Presence of Iron upon Photodegradation Invest. Ophthalmol. Vis. Sci., July 1, 2008; 49(7): 2838 - 2847. [Abstract] [Full Text] [PDF]

				C. N. Keilhauer and F. C. Delori Near-infrared autofluorescence imaging of the fundus: visualization of ocular melanin. Invest. Ophthalmol. Vis. Sci., August 1, 2006; 47(8): 3556 - 3564. [Abstract] [Full Text] [PDF]

				J. Ostojic, D. S. Sakaguchi, Y. de Lathouder, M. S. Hargrove, J. T. Trent III, Y. H. Kwon, R. H. Kardon, M. H. Kuehn, D. M. Betts, and S. Grozdanic Neuroglobin and cytoglobin: oxygen-binding proteins in retinal neurons. Invest. Ophthalmol. Vis. Sci., March 1, 2006; 47(3): 1016 - 1023. [Abstract] [Full Text] [PDF]

				R. Tzekov, T. Lin, K.-M. Zhang, B. Jackson, A. Oyejide, W. Orilla, A. D. Kulkarni, B. D. Kuppermann, L. Wheeler, and J. Burke Ocular Changes after Photodynamic Therapy Invest. Ophthalmol. Vis. Sci., January 1, 2006; 47(1): 377 - 385. [Abstract] [Full Text] [PDF]

				M. Rozanowska, W. Korytowski, B. Rozanowski, C. Skumatz, M. E. Boulton, J. M. Burke, and T. Sarna Photoreactivity of Aged Human RPE Melanosomes: A Comparison with Lipofuscin Invest. Ophthalmol. Vis. Sci., July 1, 2002; 43(7): 2088 - 2096. [Abstract] [Full Text] [PDF]