1992 Fiscal Year Final Research Report Summary
Effects on Retinal Pigment Epithelium in Vitro of Dopa and Oxygen.
| Project/Area Number |
02454409
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Ophthalmology
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| Research Institution | Keio University |
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Principal Investigator |
TANAKA Yasuhiko Keio University School of Medicine Associat Professor, 医学部, 助教授 (30051551)
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| Co-Investigator(Kenkyū-buntansha) |
AKEO Kiyoshi Keio University School of Medicine Assistant Professor, 医学部, 非常勤講師 (90146663)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Retinal Pigment Epithelium / Melanin / in vitro / Free radicals / Cell growth / Superoxide dismutase / Cell cycle / Dopa |
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| Research Abstract |
Purpose. It is possible that the effects of L-dopa and oxygen on retinal pigment epithelial (RPE) cells are dependent on tyrosinase activities because melanin precursors and free radicals are produced during melanin synthesis by tyrosinase. We compared these cytotoxic effects of L-dopa and oxygen on cell growth, superoxide dismutase (SOD) activity, and cell cycle of melanotic RPE cells with amelanotic RPE cells.
Methods. We conducted cell count, SOD activity, and flow cytometric DNA analysis of RPE cells exposed to L-dopa (100 muM and 250 muM) changing oxygen concentrations (20%, 10%, and 5%).
Results. Melanotic RPE cells were more tolerant of toxicity of dopa-oxidation than amelanotic RPE cells. SOD activity of RPE cells was increased by exposure to dopa regardless of melanin granules. A dose-dependent effect of L-dopa to arrest the cell cycle (the S phase) was more pronounced in melanotic RPE cells than in amelanotic RPE cells, and oxygen caused arrest in the G_1 phase.
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