Wavelength dependence of pyrimidine dimer formation in DNA of human skin irradiated in situ with ultraviolet light.
AUTOR(ES)
Freeman, S E
RESUMO
The UV components of sunlight are believed to be a major cause of human skin cancer, and DNA is thought to be the principal molecular target. Alterations of the intensity and wavelength distribution of solar UV radiation reaching the surface of the earth, for example by depletion of stratospheric ozone, will change the effectiveness of solar radiation in damaging DNA in human skin. Evaluation of the magnitude of such effects requires knowledge of the altered sunlight spectrum and of the action spectrum for damaging DNA in human skin. We have determined an action spectrum for the frequency of pyrimidine dimer formation induced in the DNA of human skin per unit dose of UV incident on the skin surface. The peak of this action spectrum is near 300 nm and decreases rapidly at both longer and shorter wavelengths. The decrease in our action spectrum for wavelengths less than 300 nm is attributed to the absorption of the upper layers of the skin, an in situ effect that is inherently included in our measurements. Convolution of the dimer action spectrum with the solar spectra corresponding to a solar angle of 40 degrees under current levels of stratospheric ozone (0.32-cm O3 layer) and those for 50% ozone depletion (0.16-cm O3 layer), indicate about a 2.5-fold increase in dimer formation. If the action spectrum for DNA damage that results in skin cancer resembles that for dimer induction in skin, our results, combined with epidemiological data, suggest that a 50% decrease in stratospheric ozone would increase the incidence of nonmelanoma skin cancers among white males in Seattle, Washington, by 7.5- to 8-fold, to a higher incidence than is presently seen in the corresponding population of Albuquerque, New Mexico.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=297671Documentos Relacionados
- Increased recombinational efficiency in insect cells irradiated with short wavelength ultra-violet light.
- Enzyme plus light therapy to repair DNA damage in ultraviolet-B-irradiated human skin
- Repair of Pyrimidine Dimer Damage Induced in Yeast by Ultraviolet Light
- Ultraviolet light action spectra for neoplastic transformation and lethality of Syrian hamster embryo cells correlate with spectrum for pyrimidine dimer formation in cellular DNA.
- A Method for Detecting Pyrimidine Dimers in the DNA of Bacteria Irradiated with Low Doses of Ultraviolet Light