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MacLaughlin, J. A., Anderson, R., & Holick, M. F. (1982). Spectral character of sunlight modulates photosynthesis of previtamin d3 and its photoisomers in human skin. Science, 216(4549), 1001–1003. 
Added by: Sarina (2008-12-16 20:27:07)   Last edited by: Sarina (2022-12-13 15:15:49)
Resource type: Journal Article
DOI: 10.1126/science.6281884
BibTeX citation key: MacLaughlin1982
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 Categories: Englisch = English
Keywords: Sonne = Sun, Ultraviolett = Ultraviolet, Vitamin D = Vitamin D
Creators: Anderson, Holick, MacLaughlin
Collection: Science		 Views: 1/2052
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Popularity index: 1.75%
Meine Sichtweise (Keine vollständige Zusammenfassung des Artikels! Meine Meinung muss nicht mit der Meinung der Autoren übereinstimmen! Bitte lesen Sie auch die Originalarbeit!)     
  • Eine Bestrahlung mit einer Schmalbandigen Lichtquelle mit 295-300 nm Wellenlänge wandelt wesentlich mehr 7DHC in preD3 um als das Sonnenlicht:
    •  "With exposure to 295-nm radiation, the maximum possible conversion of 7-DHC to preD3 in human epidermis was approximately 60 ± 5 percent of the original concentration of 7-DHC (Fig. 2A). At this time, a quasi-photostationary state was established with tachysterol, lumisterol, and 7-DHC representing 25 to 30, 5 to 10, and 2 to 5 percent, respectively (Fig. 2B). [...] In comparison, when the adjacent skin samples were exposed to an equivalent of 15 to 30 minutes of simulated equatorial solar radiation, the maximum preD3 produced was only 15 to 20 percent of the original 7-DHC levels (Fig. 2A), and a quasiphotostationary state was established with tachysterol3, lumisterol3, and 7- DHC representing 3 to 6, 50 to 60, and 10 to 20 percent, respectively (Fig. 2)."
    •   Sonne Schmalband
      PreD3 15 - 20 %  (19 %) 55 - 65 %  (60 %)
      Tachysterol 3 - 6 %  (5 %) 25 - 30 %  (28 %)
      Lumisterol 50 - 60 %  (57 %) 5 - 10 %  (8 %)
      7DHC 10 - 20 %  (19 %) 2 - 5 %  (4 %)
  • Sonnenlicht enthält ein Strahlungsgemisch dass eine Überdosierung von VitaminD3 verhindert
  • Struktuformeln für Umwandlungen von ProvitaminD3 zu PrävitaminD3, Lumisterol, Tachysterol und VitaminD3 sind angegeben
  • Spektrale Empfindlichkeit für Umwandlung ProvitaminD3 zu PrävitaminD3 ist angegeben
  • Absorptionsspektren von ProvitaminD3, PrävitaminD3, Tachysterol, Lumisterol sind angegeben. Tachysterol hat die höchste Absorption über 315nm, Lumisterol wird daher vermehrt gebildet




Added by: Sarina  
Abstract
The photosynthesis of previtamin D3 from 7-dehydrocholesterol in human skin was determined after exposure to narrow-band radiation or simulated solar radiation. The optimum wavelengths for the production of previtamin D3 were determined to be between 295 and 300 nanometers. When human skin was exposed to 295-nanometer radiation, up to 65 percent of the original 7-dehydrocholesterol content was converted to previtamin D3. In comparison, when adjacent skin was exposed to simulated solar radiation, the maximum formation of previtamin D3 was about 20 percent. Major differences in the formation of lumisterol3, and tachysterol3 from previtamin D3 were also observed. It is concluded that the spectral character of natural sunlight has a profound effect on the photochemistry of 7-dehydrocholesterol in human skin.
  
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