title: Assessment of cyclobutane pyrimidine dimers by digital photography in human skin.
abstract: UV-mediated DNA damage and repair are important mechanisms in research on UV-induced carcinogenesis. UV-induced DNA-damage and repair can be determined by immunohistochemical staining of photoproduct positive nuclei of keratinocytes in the epidermis. We developed a new method of analysing and quantifying thymine dimer (TT-CPD) positive cells in the epidermis. Normal skin of healthy controls was exposed to UVB ex vivo and in vivo. Skin samples were immunohistochemically stained for TT-CPDs. Digital images of the epidermis were quantified for TT-CPDs both visually and digitally. There was a UVB-dose dependent induction of TT-CPDs present in the ex vivo UVB-irradiated skin samples. The linear measurement range of the digital quantification was increased compared to the manual counting. The average 24-hour repair rate of the initiated TT-CPDs elicited by the UVB irradiation at T=0 of the 8 HCs showed a 34% decrease of TT-CPD photoproducts by the manual counting method and a 51% decrease determined by digital counting. The digital quantification method improves immunohistochemical quantification of DNA photo damage. It is more sensitive in measuring the extent of DNA-damage per nucleus.
authors.affiliation: University Medical Centre Utrecht, Department of Dermatology & Allergology, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. o.tenberge@umcutrecht.nl
authors.forename: Onno
authors.initials: O
authors.lastname: ten Berge
authors.forename: Sara G A
authors.initials: SG
authors.lastname: van Velsen
authors.forename: Barbara
authors.initials: B
authors.lastname: Giovannone
authors.forename: Carla A F M
authors.initials: CA
authors.lastname: Bruijnzeel-Koomen
authors.forename: Edward F
authors.initials: EF
authors.lastname: Knol
authors.forename: Kees
authors.initials: K
authors.lastname: Guikers
authors.forename: Huib
authors.initials: H
authors.lastname: van Weelden
mesh_terms: D000328:Adult; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D004307:Dose-Response Relationship, Radiation; D004817:Epidermis / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016014:Linear Models; D010781:Photography / Q000379:methods*; D011740:Pyrimidine Dimers / Q000032:analysis*; D015203:Reproducibility of Results; D012867:Skin / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects*; D013997:Time Factors; D014466:Ultraviolet Rays; D055815:Young Adult
chemical_list: D011740:Pyrimidine Dimers; D004247:DNA