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SUNLIGHT‐INDUCED PYRIMIDINE DIMERS IN HUMAN SKIN FIBROBLASTS IN COMPARISON WITH DIMERIZATION AFTER ARTIFICIAL UV‐IRRADIATION
Author(s) -
Niggli Hugo J.,
Röthlisberger Rudolf
Publication year - 1988
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1988.tb02833.x
Subject(s) - pyrimidine dimer , thymine , dimer , irradiation , xeroderma pigmentosum , cytosine , chemistry , sunlight , noon , photochemistry , pyrimidine , thymidine , dna , stereochemistry , dna damage , biochemistry , organic chemistry , optics , physics , astronomy , nuclear physics
— We compared artificial UV‐sources such as germicidal‐ or sun‐lamps with summer noon sunlight in Switzerland for selective efficiency in the induction of pyrimidine dimers in the DNA of human cells. In our studies we determined cytosine‐thymine (C‐T) as well as thymine‐thymine dimer densities (T‐T) by high pressure liquid chromatography in cultures of xeroderma pigmentosum cells of group A. Using far‐UV light from a germicidal lamp, we found a rate of formation per Jirr 2 for C‐T and T‐T of 0.0019% and 0.0024%, respectively, of the total thymine radioactivity in hydrolysates of [ 3 H]thymidine labeled cells. After irradiation with an unfiltered sunlamp we measured a rate of formation of 0.0005% per Jm‐ 2 both for C‐T and T‐T, based on the sunlamp emission of 297 ±4 nm wavelength. Utilization of Kodacel‐ or Mylar‐filters lowered the rate of dimerization by a factor of 2 and 60, respectively. One hour of irradiation with noon summer sunlight induced 0.038 ±0.012% C‐T and 0.036 ±0.011% T‐T. This extent of dimer production is equivalent to 15 Jm ‐2 of far‐UV exposure at 254 nm.