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Tytuł oryginału: Photoreactivity of aged human RPE melanosomes: a comparison with lipofuscin.
Autorzy: Różanowska Małgorzata, Korytowski Witold, Różanowski Bartosz, Skumatz Christine, Boulton Mike E., Burke Janice M., Sarna Tadeusz
Źródło: Invest. Ophthalmol. Vis. Sci. 2002: 43 (7) s.2088-2096, il., bibliogr. 57 poz.
Sygnatura GBL: 311,976

Hasła klasyfikacyjne GBL:
  • okulistyka

    Typ dokumentu:
  • tytuł obcojęzyczny
  • praca opublikowana za granicą
  • praca kliniczna

    Wskaźnik treści:
  • ludzie
  • dzieci 2-5 r.ż.
  • dzieci 6-12 r.ż.
  • dzieci 13-18 r.ż.
  • dorośli 19-44 r.ż.
  • dorośli 45-64 r.ż.
  • dorośli = 65 r.ż.

    Streszczenie angielskie: Purpose. To determine whether aging is accompanied by changes in aerobic photoreactivity of retinal pigment epithelial (RPE) melanosomes isolated from human donors of different ages, and to compare the photoreactivity of aged melanosomes with that of RPE lipofuscin. Methods. Human RPE pigment granules were isolated from RPE cells pooled into groups according to the age of the donors. Photoreactivity was determined by blue-light-induced oxygen uptake and photogeneration of reactive oxygen species. Short-lived radical intermediates were detected by spintrapping, hydrogen peroxide by an oxidase electrode, singlet oxygen by cholesterol assay, and lipid hydroperoxides by iodometric assay. Results. Blue-light photoexcitation of melanosomes resulted in age-related increases in both oxygen uptake and the accumulation of superoxide anion spin adducts. The efficiencies of these processes, however, were still significantly lower than that induced by photoexcited lipofuscin. During irradiation of melanosomes, a substantial amount of oxygen was converted into hydrogen peroxide, whereas for lipofuscin, hydrogen peroxide accounted for not more than 3 p.c. of oxygen consumed. In contrast to lipofuscin, photoexcited melanosomes did not substantially increase the rate of oxidative reactions in the presence of polyunsaturated lipids of albumin. However, oxygen uptake was significantly elevated in the presence of ascorbate. Thus, the rate of photo-induced oxygen uptake in samples containing both ascorbate and melanosomes approached that observed in lipofuscin samples...

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