The specific aims for this project are: 1) To isolate and identify some of the molecular species responsible for the photochemically induced age-related fluorescence (particularly in the 360 nm excitation/440 nm emission, and 435 nm excitation/520 nm emission) in the human lens. This will be performed by the isolation and purification of specific fluorescent peptides (enzymatic hydrolysis and chromatography); amino acid composition and sequencing, and further hydrolysis of the peptides to isolate the purified chromophores. Spectroscopic analyses (UV, fluorescence, phosphorescence, GC mass spectrometry and NMR spectroscopy will be performed at certain stages of this procedure to monitor and identify the compounds isolated. 2) To elucidate the molecular mechanisms of photochemical lens damage by studying the photochemistry of purified lens proteins and appropriate model compounds. 3) To probe the distribution of lens protein fractions (alpha, beta, gamma-crystallin and insoluble) using laser excited tryptophan fluorescence decay measurements on intact human lenses (""""""""optical dissection""""""""). Knowing the photochemical reactivities of the various lens protein fractions and their distribution should permit us to predict which region(s) of the intact lens are most susceptible to photochemical damage. 4) In addition to our conventional irradiation source which enables us to bathe whole lenses with photons, we also propose to utilize our laser photolysis apparatus to study localized photodamage in whole lenses and to detect such damage by laser excited fluorescence and ESR spectroscopy. 5) To correlate our in vitro fluorescence studies (on human lenses) with in vivo UV-slit lamp densitography. We have recently demonstrated the feasibility of this approach and we have instituted a study on normal individuals as well as patients on phototherapy. This may enable us to detect changes in lens fluorescence several years prior to their becoming manifest by usual slit lamp examinations. 6) To isolate and identify the photochemical product(s) produced when animals are exposed to UV radiation following a dose of the sensitizer 8-methoxypsoralen. Spectroscopic analyses (as outlined in 1) will be employed. 7) To relate the molecular changes caused by direct and photosensitized UV radiation to morphological events.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY001575-11
Application #
3256016
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1978-06-01
Project End
1986-11-30
Budget Start
1985-06-01
Budget End
1986-11-30
Support Year
11
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Emory University
Department
Type
Schools of Medicine
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Lerman, S (1992) Free radical damage and defense mechanisms in the ocular lens. Lens Eye Toxic Res 9:9-24
Lerman, S (1991) NMR & fluorescence studies on human and animal lenses. Lens Eye Toxic Res 8:121-54
Lerman, S; Mandal, K (1991) Fluorescence polarization and circular dichroism studies on aging human lens proteins. Ophthalmic Res 23:147-53
Lerman, S; Mandal, K; Misra, B et al. (1991) Phototoxicity involving the ocular lens: in vivo and in vitro studies. Photochem Photobiol 53:243-7
Lerman, S; Wandel, T; Schechter, A et al. (1991) In vivo non-invasive studies on the human lens. Magn Reson Imaging 9:525-32
Lerman, S (1991) Evaluation of risk factors in human cataractogenesis. Dev Ophthalmol 21:120-8
Lerman, S (1990) Biophysical methods to monitor lens aging and pre-cataractous changes in vivo. Lens Eye Toxic Res 7:243-9
Lerman, S (1989) In vivo lens fluorescence as a cataract marker. Dev Ophthalmol 17:60-4
Lerman, S; Moran, M; Matthews, N (1989) Photographic and spectroscopic correlations of human cataracts. Ophthalmic Res 21:18-26
Lerman, S (1989) In vivo evaluation of lenticular phototoxicity. Lens Eye Toxic Res 6:301-8

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