Investigation of laser-induced retinal damage. Annual report, 1 Apr 91-31 Mar 92
Technical Report
·
OSTI ID:7049858
Laser-induced, photooxidative damage in ocular tissue was studied with a quantitative assay using high performance liquid chromatography (HPLC) to separate oxidized and reduced ascorbic acid in exposed tissue components. We demonstrated that ascorbic acid, incubated with whole, bovine retinal pigment epithelial (RPE) cells, was oxidized when the reaction mixture was exposed to the output of an argon-ion continuous wave laser The amount of ascorbic acid oxidized was proportional to the irradiance of the sample, and the reaction was wavelength-dependent, with short-wavelength visible light more effective than long-wavelengths in driving the, reaction. The photosensitizing activity was associated with the RPE melanin pigment granules, and was not lost after disrupting or heating the RPE cells. Because melanin was known to form free radicals when illuminated, we hypothesized that ascorbic acid detoxified the light-activated melanin free radicals while being itself oxidized in process. If the supply of reduced ascorbic acid were exhausted, however, the activated melanin could have been the source of tissue-damaging radicals. This model was consistent with a photochemical damage mechanism involving light-activated melanin.
- Research Organization:
- Texas Univ., San Antonio, TX (United States). Health Science Center
- OSTI ID:
- 7049858
- Report Number(s):
- AD-A-250173/2/XAB; CNN: AFOSR-91-0208
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560400* -- Other Environmental Pollutant Effects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANTIOXIDANTS
ARGON
ASCORBIC ACID
BIOLOGICAL EFFECTS
BODY
BODY AREAS
CHEMICAL REACTIONS
CHROMATOGRAPHY
ELECTROMAGNETIC RADIATION
ELEMENTS
EYES
FACE
FLUIDS
GAS LASERS
GASES
HEAD
HYDROXY COMPOUNDS
LASER RADIATION
LASERS
LIQUID COLUMN CHROMATOGRAPHY
MELANIN
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PIGMENTS
RADIATIONS
RADICALS
RARE GASES
REDOX REACTIONS
RETINA
SENSE ORGANS
SENSITIVITY
SEPARATION PROCESSES
VITAMINS
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANTIOXIDANTS
ARGON
ASCORBIC ACID
BIOLOGICAL EFFECTS
BODY
BODY AREAS
CHEMICAL REACTIONS
CHROMATOGRAPHY
ELECTROMAGNETIC RADIATION
ELEMENTS
EYES
FACE
FLUIDS
GAS LASERS
GASES
HEAD
HYDROXY COMPOUNDS
LASER RADIATION
LASERS
LIQUID COLUMN CHROMATOGRAPHY
MELANIN
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PIGMENTS
RADIATIONS
RADICALS
RARE GASES
REDOX REACTIONS
RETINA
SENSE ORGANS
SENSITIVITY
SEPARATION PROCESSES
VITAMINS