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Preliminary Study on Cataractous Human Lenses Using Near‐Infrared Fourier Transform Raman Spectroscopy
Author(s) -
Huang FuYung,
Ho Yuh,
Hsu MingChing,
Wong FongZo
Publication year - 1999
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.199900016
Subject(s) - chemistry , tryptophan , nucleus , cortex (anatomy) , raman spectroscopy , tyrosine , lens (geology) , fourier transform infrared spectroscopy , biophysics , amino acid , biochemistry , optics , physics , neuroscience , biology , microbiology and biotechnology
Raman vibrations of the fingerprint of aromatic amino acid residues were analyzed to study the changes of cataractous lens protein in the cortex and nucleus at various ages. Tryptophan content, analyzed by the quantification of I 758 /I 1448 ratio, shows the damage (modification) of tryptophan residue in the nucleus is caused primarily by the formation of cataracts, not by the aging process. Microenvironmental changes of tryptophan and tyrosine were analyzed by the intensity ratios of I 879 /I 758 and I 829 /I 853 , respectively. The decrease of the ratio of I 879 /I 758 , from 0.9 to 0.6 in the nucleus and from 0.7 to 0.6 for the cortex, reveal that more buried tryptophan residues become exposed in the cortex than in the nucleus during cataractogenesis, especially for non‐senile cataractous lenses. The ratio of I 829 /I 853 is around 1.0 for both cortical and nuclear proteins at various ages, indicating some tyrosine residues have undergone a change in their hydrogen bonding environment. When compared to previous studies, we found that a normal (clear) lens has a higher peak at 1617 cm −1 than at 1604 cm −1 , while a dense opaque or brunescent lens shows stronger intensity at 1604 cm −1 than at 1617 cm −1 , suggesting the ratio of I 1617 /I 1604 can be used to evaluate the human lens morphology.