Investigation of laser-induced retinal damage. Annual report, 1 Apr 91-31 Mar 92
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
Similar Records
Mechanical and photo-fragmentation processes for nanonization of melanin to improve its efficacy in protecting cells from reactive oxygen species stress
Transport of thiol-conjugates of inorganic mercury in human retinal pigment epithelial cells
Related Subjects
ASCORBIC ACID
REDOX REACTIONS
LASER RADIATION
BIOLOGICAL EFFECTS
RETINA
SENSITIVITY
ANTIOXIDANTS
ARGON
GAS LASERS
LIQUID COLUMN CHROMATOGRAPHY
MELANIN
RADICALS
BODY
BODY AREAS
CHEMICAL REACTIONS
CHROMATOGRAPHY
ELECTROMAGNETIC RADIATION
ELEMENTS
EYES
FACE
FLUIDS
GASES
HEAD
HYDROXY COMPOUNDS
LASERS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PIGMENTS
RADIATIONS
RARE GASES
SENSE ORGANS
SEPARATION PROCESSES
VITAMINS
560400* - Other Environmental Pollutant Effects