Human skin is constantly exposed to solar ultraviolet radiation (UVR), the most prevalent environmental carcinogen. Humans have the unique ability among mammals to respond to UVR by increasing their skin pigmentation, a protective process driven by melanin synthesis in epidermal melanocytes. The molecular mechanisms used by melanocytes to detect and respond to long-wavelength UVR (UVA) are not ...

While short exposure to solar ultraviolet radiation (UVR) can elicit increased skin pigmentation, a protective response mediated by epidermal melanocytes, chronic exposure can lead to skin cancer and photoaging. However, the molecular mechanisms that allow human skin to detect and respond to UVR remain incompletely understood. UVR stimulates a retinal-dependent signaling cascade in human melano...

BACKGROUND Mutagenic DNA repair (MDR) transiently increases mutation rate through the activation of low-fidelity repair polymerases in response to specific, DNA-damaging environmental stress conditions such as ultraviolet radiation (UVR) exposure. These repair polymerases also confer UVR tolerance, intimately linking mutability and survival in bacteria that colone habitats subject to regular UV...

Zooplankton have evolved several mechanisms to deal with environmental threats, such as ultraviolet radiation (UVR), and in order to identify strategies inherent to organisms exposed to different UVR environments, we here examine life-history traits of two lineages of Daphnia pulex. The lineages differed in the UVR dose they had received at their place of origin from extremely high UVR stress a...

Introduction Ultraviolet radiation (UVR) in sunlight is the most important cause of skin damage and aging.'"' This form of radiation causes skin aging by several mechanisms, including free-radical generation, DNA damage, collagen breakdown, the induction of immune defects, and cell death.'-5 In addition, repeated damage to the skin by sunburn is a primarily risk factor for the development of cu...

Ambient ultraviolet radiation (UVR) is known to have direct negative effects on aquatic bacteria at the molecular level, damaging DNA, and at the level of community metabolism, but little is known about the effects of UVR at the cellular level. In order to study the direct and indirect effects of UVR on bacterioplankton, we developed a staining protocol based on the exclusion nucleic acid stain...

ion and evaluation of studies. Each study that met the inclusion criteria was abstracted by two independent reviewers using the standard Community Guide abstraction process. Disagreements between reviewers were resolved by consensus. Community Guide methods were used to assess each study for internal and external validity (Appendix A, available Figure 2. Search yield for evidence included in MM...

PURPOSE To investigate the effect of age on ultraviolet radiation-B (UVR-B)-induced cataract and to detect the maximum acceptable dose in rats of different age groups. METHODS Four age groups of 20 rats each, aged 3, 6, 10, and 18 weeks, were included. Each age group was divided into five UVR-B dose subgroups. The rats were unilaterally exposed to UVR-B (lambda(max) = 302.6 nm, lambda(0.5) = ...

Although epidemiological evidence shows an association between arsenic in drinking water and increased risk of skin, lung, and bladder cancers, arsenic compounds are not animal carcinogens. The lack of animal models has hindered mechanistic studies of arsenic carcinogenesis. Previously, this laboratory found that low concentrations of arsenite (the likely environmental carcinogen) which are not...