In a study on the dose-response relationship for longwave UVA (UVA1; 340-400 nm) @entity105 in hairless @entity19 scratch marks appeared after months of daily exposure as an unwanted side effect. @entity5 induction in the highest of the 4 tested dose groups (receiving a daily dose of 430 kJ/m2 of 365-nm radiation) could not be determined because extensive scarification occurred prior to the development of any @entity5 . The induction of scratch marks could be scored and quantified in all 4 dose groups tested. The UVA1 dose-dependencies for the induction of @entity5 and scratch marks were compared. We found that the induction of scratch marks depended mainly on the cumulative UVA1 exposure, whereas @entity5 induction showed a lesser dose-dependency. An attempt was made to prevent the apparent pruritogenic effect of UVA1 irradiation and to understand its mechanism. The influence of @entity6009 , a @entity750 / @entity112 antagonist, on the UVA1 induction of scratch marks was tested in groups of 8 @entity19 daily irradiated with 430 kJ/m2. No difference was found between treated and untreated animals. Histological examination of skin biopsies from irradiated @entity19 from the 430-kJ/m2 dose group from the UVA1 carcinogenic experiment, showed no changes in numbers of mast cells or other inflammatory features when compared to skin biopsies from unirradiated control @entity19 . This indicated that UVA1-induced scratching is not mediated through mast cell release of @entity750 and/or @entity112 . An adequate therapeutic treatment which can prevent UVA1-induced scratching would enable us to test @entity5 induction with UVA1 over a larger dose range, and may provide additional insight in how this radiation damages the skin. It remains conjectural whether there exists an analogous UVA-induced @entity111 in @entity1 skin.

Chronic UVA (365-nm) irradiation induced scratching in hairless XXXX : dose-time dependency and the effect of @entity6009 .

@entity1 :: ('9606', 'Species') :: ['human'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'Tumor', 'tumors'] @entity111 :: ('MESH:D011537', 'Disease') :: ['pruritus'] @entity750 :: ('MESH:D012701', 'Chemical') :: ['serotonin'] @entity112 :: ('MESH:D006632', 'Chemical') :: ['histamine'] @entity6009 :: ('MESH:D007650', 'Chemical') :: ['ketanserin'] @entity105 :: ('MESH:D063646', 'Disease') :: ['carcinogenesis']
@entity19 :: (10090,Species) :: ['mice']
