| Impact of UVR-A on whole human lenses, supernatants of buffered human lens homogenates, and purified argpyrimidine and 3-OH-kynurenine. | |
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MedLine Citation:
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PMID: 15799737 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: Yellow chromophores and fluorescent compounds accumulate in the lens with age. Some of these compounds are photochemically active. The present study aimed to examine the photochemical effect of ultraviolet radiation-A (UVR-A) on the human lens. METHODS: Intact human lenses and supernatants of buffered lens homogenates were exposed to UVR-A. The effect of UVR-A was evaluated by time-resolved and steady-state fluorescence spectroscopy, visual evaluation of colour and protein gel electrophoresis. RESULTS: Intact lenses exposed to UVR-A showed no changes in time-resolved or steady-state fluorescence properties but the yellow coloration was visibly attenuated. The supernatants of buffered lens homogenates exposed to UVR-A demonstrated a reduction in time-resolved and steady-state fluorescent properties and protein cross-linking. CONCLUSIONS: Exposure of the intact lens to UVR-A causes chromophore bleaching without affecting fluorescence, indicating that non-fluorescent chromophores have been destroyed. After homogenization, both chromophores and fluorophores from the lens suffer damage and proteins aggregate. This indicates that powerful mechanisms of protection against UVR-A found in the intact lens are disturbed by homogenization of the lens, suggesting that isolated lens proteins cannot be used as a model system for studying cataractogenesis. Hypothetically, the protective mechanism could be related to the rigidly packed three-dimensional structure of the lens proteins or to the abundance of antioxidative and free radical scavenging defence systems. |
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Authors:
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Line Kessel; Stanislav Kalinin; Vladislav Soroka; Michael Larsen; Lennart B-A Johansson |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Acta ophthalmologica Scandinavica Volume: 83 ISSN: 1395-3907 ISO Abbreviation: Acta Ophthalmol Scand Publication Date: 2005 Apr |
Date Detail:
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Created Date: 2005-03-31 Completed Date: 2005-05-26 Revised Date: 2008-03-17 |
Medline Journal Info:
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Nlm Unique ID: 9507578 Medline TA: Acta Ophthalmol Scand Country: Denmark |
Other Details:
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Languages: eng Pagination: 221-7 Citation Subset: IM |
Affiliation:
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Department of Ophthalmology. Herlev Hospital. University of Copenhagen, Herlev, Denmark. line.kessel@dadlnet.dk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Aged Animals Buffers Crystallins / metabolism* Electrophoresis, Polyacrylamide Gel Humans Kynurenine / analogs & derivatives*, radiation effects* Lens, Crystalline / metabolism, radiation effects* Middle Aged Ornithine / analogs & derivatives*, radiation effects* Pigments, Biological / metabolism Pyrimidines / radiation effects* Radiation Dosage Radiation Injuries, Experimental / metabolism Spectrometry, Fluorescence Ultraviolet Rays* |
| Chemical | |
Reg. No./Substance:
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0/Buffers; 0/Crystallins; 0/Pigments, Biological; 0/Pyrimidines; 0/argpyrimidine; 343-65-7/Kynurenine; 484-78-6/3-hydroxykynurenine; 7006-33-9/Ornithine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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