A revised action spectrum for vitamin D synthesis by suberythemal UV radiation exposure in humans in vivo.

Action spectra are important biological weighting functions for risk/benefit analyses of ultraviolet (UV) radiation (UVR) exposure. One important human benefit of exposure to terrestrial solar UVB radiation (∼295 to 315 nm) is the cutaneous synthesis of vitamin D that is initiated by the photoconversion of 7-dehydrocholesterol to previtamin D An action spectrum for this process that is followed by other nonphotochemical steps to achieve biologically active vitamin D has been established from ex vivo data and is widely used, although its validity has been questioned. We tested this action spectrum in vivo by full- or partial-body suberythemal irradiation of 75 healthy young volunteers with five different polychromatic UVR spectra on five serial occasions.

Melanin has a Small Inhibitory Effect on Cutaneous Vitamin D Synthesis: A Comparison of Extreme Phenotypes.

Epidemiology suggests that melanin inhibits cutaneous vitamin D synthesis by UVR. Laboratory investigations assessing the impact of melanin on vitamin D production have produced contradictory results. We determined the effect of melanin on vitamin D photosynthesis in healthy young volunteers (n = 102) of Fitzpatrick skin types II-VI (white to black).

The Hepatitis C Awareness Through to Treatment (HepCATT) study: improving the cascade of care for hepatitis C virus-infected people who inject drugs in England.

Background And Aims: Previous studies have shown low rates of diagnosis and treatment of hepatitis C virus (HCV) infection in people who inject drugs (PWID). Our aims were to test the effect of a complex intervention [Hepatitis C Awareness Through to Treatment (HepCATT)] in drug and alcohol clinics-primarily, on engagement of HCV-positive PWID with therapy and, secondarily, on testing for HCV, referral to hepatology services and start of HCV treatment.

Design And Setting: A non-randomized pilot study in three specialist addiction clinics in England comparing an intervention year (starting between September 2015 and February 2016) with a baseline year (2014), together with three control clinics.

Sub-optimal Application of a High SPF Sunscreen Prevents Epidermal DNA Damage in Vivo.

The cyclobutane pyrimidine dimer (CPD) is a potentially mutagenic DNA photolesion that is the basis of most skin cancers. There are no data on DNA protection by sunscreens under typical conditions of use. The study aim was to determine such protection, in phototypes I/II, with representative sunscreen-user application.

The acute effects of ultraviolet radiation on the blood transcriptome are independent of plasma 25OHD.

The molecular basis of many health outcomes attributed to solar ultraviolet radiation (UVR) is unknown. We tested the hypothesis that they may originate from transcriptional changes in blood cells. This was determined by assessing the effect of fluorescent solar simulated radiation (FSSR) on the transcriptional profile of peripheral blood pre- and 6h, 24h and 48h post-exposure in nine healthy volunteers.

Hepatitis C - Assessment to Treatment Trial (HepCATT) in primary care: study protocol for a cluster randomised controlled trial.

Background: Public Health England (PHE) estimates that there are upwards of 160,000 individuals in England and Wales with chronic hepatitis C virus (HCV) infection, but until now only around 100,000 laboratory diagnoses have been reported to PHE and of these 28,000 have been treated. Targeted case-finding in primary care is estimated to be cost-effective; however, there has been no robust randomised controlled trial evidence available of specific interventions. Therefore, this study aims to develop and conduct a complex intervention within primary care and to evaluate this approach using a cluster randomised controlled trial.

Sun behaviour and personal UVR exposure among Europeans on short term holidays.

Solar ultraviolet radiation (UVR) is known to be the main cause of skin cancer, the incidence of which is rising with national differences across Europe. With this observation study we aimed to determine the impact of nationality on sun behaviour and personal UVR exposure on sun and ski holidays. 25 Danish and 20 Spanish sun-seekers were observed during a sun holiday in Spain, and 26 Danish and 27 Austrian skiers were observed during a ski holiday in Austria.

Sun and ski holidays improve vitamin D status, but are associated with high levels of DNA damage.

Skin cancer is caused by solar UVR, which is also essential for vitamin D production. DNA damage (thymine dimers: T-T dimers) and vitamin D (25(OH)D) synthesis are both initiated by solar UVB. We aimed to investigate the simultaneous adverse and beneficial effects of solar UVB exposure in holidaymakers.

UVA1 is skin deep: molecular and clinical implications.

Long wavelength UVA1 (340-400 nm) is the main component of terrestrial UVR and is increasingly used in skin phototherapy. Its damage to critical biomolecules such as DNA has been widely attributed to its ability to generate reactive oxygen species (ROS) via other chromophores. However recent studies in vitro and in vivo have shown that UVA1 has a specific ability to generate cyclobutane pyrimidine dimers (CPD), especially thymine dimers (T<>T), and that this is probably due to direct absorption of UVR.

Ultraviolet radiation-induced inflammation as a model for cutaneous hyperalgesia.

The effects of UVA-I and solar simulated radiation on skin sensitivity to thermal and mechanical stimuli were compared in normal volunteers. Individual minimal erythema doses (MED) for each source were determined and previously unexposed buttock skin was exposed to 1, 2 and 3 MED of each spectrum. Erythema, and mechanical and thermal pain thresholds were quantified from 3 to 72 hours post-irradiation.

Ultraviolet radiation-induced erythema in human skin.

We have evaluated UVR-induced erythema in previously unexposed buttock skin of volunteers of skin types I, II, III, and IV. Studies were done with solar-simulated radiation (SSR), UVB, and UVAI and we determined the just perceptible minimal erythema dose (MED) and, in some cases, quantified erythema with a reflectance device. The results show that there is a trend for increased SSR MED with skin type, with the MED of skin type IV being approximately twice that of skin type I, a smaller difference than one might have expected.