A personal UV dosimeter that can quantitatively assess high exposure solar UVA exposures has been developed. The chemical polyphenylene oxide has been previously reported on its ability to measure high UVB exposures. This current research has found that polyphenylene oxide, cast in thin film form, is responsive to both the UVA and UVB parts of the solar spectrum. Further to this, the UVB wavele...

Deleterious effects of UV radiation in tissue are usually attributed to different mechanisms. Absorption of UVB radiation in cell constituents like DNA causes photochemical reactions. Absorption of UVA radiation in endogenous photosensitizers like vitamins generates singlet oxygen via photosensitized reactions. We investigated two further mechanisms that might be involved in UV mediated cell ti...

Long wavelength ultraviolet radiation (UVA, 320-400 nm) interacts with chromophores present in human cells to induce reactive oxygen species (ROS) that damage both DNA and proteins. ROS levels are amplified, and the damaging effects of UVA are exacerbated if the cells are irradiated in the presence of UVA photosensitizers such as 6-thioguanine (6-TG), a strong UVA chromophore that is extensivel...

The effect of 8-methoxypsoralen-UVA therapy on the catalysis of histidine to trans-urocanic acid by histidine ammonia lyase (HAL, EC 4.3.1.3) was examined using an enzymatic assay from Sigma-Aldrich where the growth of the trans-urocanic acid peak at 277 nm was monitored. A Rayonet Photochemical Mini Reactor (Model RMR-600) equipped with eight, 3500 Å light sources and a custom UVA filter (Mode...

BACKGROUND Photodegradation of certain vitamins such as riboflavins, carotinoids, tocopherol, and folate has been well-documented. Previous observations suggest that ultraviolet (UV) radiation may cause folate deficiency. This is of great importance since folate deficiency is also known to be linked with the development of neural tube defects. To investigate the influence of UVA radiation on se...

We examined the role of UVR (UV radiation) (UVA, 320-400 nm; UVB, 290-320 nm; and the combination of UVA and UVB) as a promoter in the induction of cutaneous melanoma. One hundred and seventy hairless mice (Skh-hr2), 6-8 weeks old, were treated in 8 groups: group I, DMBA [7,12-dimethylbenz(a)anthracene] plus UVA; group II, DMBA plus UVA plus UVB; group III, DMBA plus UVB; group IV, DMBA; group ...

UVA (320-400 nm) and UVB (290-320 nm) are the major components of solar UV irradiation, which is associated with various pathological conditions. UVB causes direct damage to DNA of epidermal cells and is mainly responsible for erythema, immunosuppression, photoaging, and skin cancer. UVA has oxidizing properties that can cause damage or enhance UVB damaging effects on skin. On the other hand, U...

UVA contributes to the pathogenesis of skin aging by downregulation of procollagen I content and induction of matrix metalloproteinase (MMP)-associated responses. Application of antioxidants such as lycopene has been demonstrated as a convenient way to achieve protection against skin aging. Lycogen™, derived from the extracts of Rhodobacter sphaeroides, exerts several biological effects similar...

Abstract In the 19th century when arsenic was recommended treatment for psoriasis, little consideration given to toxic side-effects of potent carcinogen. Thomas Girdlestone, an English physician, is said have been first advocate use treat psoriasis. Girdlestone prescribed Fowler’s solution, a solution potassium arsenite 1%. 1876, Alexander John Balmanno Squire inadvertently discovered dithranol...