SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Sunburn

201

The increase in reports of novel diseases in a wide range of ecosystems, both terrestrial and marine, has been linked to many factors including exposure to novel pathogens and changes in the global climate. Prevalence of skin cancer in particular has been found to be increasing in humans, but has not been reported in wild fish before. Here we report extensive melanosis and melanoma (skin cancer) in wild populations of an iconic, commercially-important marine fish, the coral trout Plectropomus leopardus. The syndrome reported here has strong similarities to previous studies associated with UV induced melanomas in the well-established laboratory fish model Xiphophorus. Relatively high prevalence rates of this syndrome (15%) were recorded at two offshore sites in the Great Barrier Reef Marine Park (GBRMP). In the absence of microbial pathogens and given the strong similarities to the UV-induced melanomas, we conclude that the likely cause was environmental exposure to UV radiation. Further studies are needed to establish the large scale distribution of the syndrome and confirm that the lesions reported here are the same as the melanoma in Xiphophorus, by assessing mutation of the EGFR gene, Xmrk. Furthermore, research on the potential links of this syndrome to increases in UV radiation from stratospheric ozone depletion needs to be completed.

Concepts: Cancer, Ultraviolet, Melanoma, Ozone depletion, Skin cancer, Sunburn, Sunscreen, Great Barrier Reef

169

Sunscreens protect the skin against erythemal radiation (Eer). But at the same time they reduce the effective radiation dose (EVD) responsible for the formation of previtamin D in the skin. The paper describes a calculation method for optimizing the ratio EVD/Eer behind sunscreens e.g. with SPF 5, 15 and 30 respectively. Taking into account that a majority of people in industrialized countries suffer from a shortage in vitamin D even in summer time, the ratio Evd/Eer is a new and important criterion for the quality of sunscreens. Furthermore the exposure time tvd needed per day for forming the equivalent of the recommended amount of 2000 IU of vitamin D per day for skin type 2 is estimated when sunscreens with different filter compositions are used. In vitro experiments show a significant increase of the conversion of 7-dehydrocholesterol (7-DHC) to previtamin D when exposed to artificial solar radiation behind an experimental sunscreen optimized for previtamin D production compared to a commercial sunscreen having the same SPF.

Concepts: Vitamin D, Ultraviolet, Sunlight, Skin, Sunburn, Sunscreen, Effective dose, Risks and benefits of sun exposure

144

To develop a novel plasmonic nanosensing technique to monitor the exposure levels of UV light for sunlight disease prevention.

Concepts: Ultraviolet, Nanoparticle, Sun, Sunlight, Gold, Sunburn, Sunscreen, Light therapy

43

At our body surface, the epidermis absorbs UV radiation. UV overexposure leads to sunburn with tissue injury and pain. To understand how, we focus on TRPV4, a nonselective cation channel highly expressed in epithelial skin cells and known to function in sensory transduction, a property shared with other transient receptor potential channels. We show that following UVB exposure mice with induced Trpv4 deletions, specifically in keratinocytes, are less sensitive to noxious thermal and mechanical stimuli than control animals. Exploring the mechanism, we find that epidermal TRPV4 orchestrates UVB-evoked skin tissue damage and increased expression of the proalgesic/algogenic mediator endothelin-1. In culture, UVB causes a direct, TRPV4-dependent Ca(2+) response in keratinocytes. In mice, topical treatment with a TRPV4-selective inhibitor decreases UVB-evoked pain behavior, epidermal tissue damage, and endothelin-1 expression. In humans, sunburn enhances epidermal expression of TRPV4 and endothelin-1, underscoring the potential of keratinocyte-derived TRPV4 as a therapeutic target for UVB-induced sunburn, in particular pain.

Concepts: Cancer, Ultraviolet, Electromagnetic spectrum, Skin, Melanin, Sunburn, Sunscreen, Sun tanning

42

Introduction: Melanoma is considered a generally preventable cancer, with excessive ultraviolet radiation (UVR) exposure being a strong causal factor. UVR exposure following a melanoma diagnosis can be modified to reduce risk of second primary melanomas. The goal of this study was to compare measures of UVR exposure and protection behaviors between long-term melanoma survivors and controls.Methods: Participants from a previously conducted case-control study were recruited for a cross-sectional survey. Melanoma cases were 25 to 59 years old at diagnosis; controls were age and sex matched. Participants were asked about UVR exposure and protection measures used in the past year, and comparisons between melanoma survivors and controls were conducted using logistic regression models, adjusting for potential confounders.Results: A total of 724 (62.0%) long-term melanoma survivors and 660 (59.9%) controls completed the follow-up survey. Melanoma survivors were significantly less likely to report high sun exposure on a typical weekday [OR, 0.72 (0.55-0.94)], sunburns [OR, 0.40 (0.30-0.53)], or indoor tanning [OR, 0.20 (0.09-0.44)] than controls; however, high sun exposure on a typical weekend day was similar. Report of optimal sun protection behaviors was higher in melanoma survivors compared with controls. However, a few melanoma survivors reported indoor tanning, 10% reported intentionally seeking sun to tan, and 20% reported sunburns.Conclusions: Although long-term melanoma survivors reported healthier UVR exposure and protection behaviors compared with controls, a sizeable proportion still reported elevated sun exposure, sunburns, and suboptimal UVR protection behaviors.Impact: Opportunities remain for improving sun protection to reduce future melanoma risk among melanoma survivors. Cancer Epidemiol Biomarkers Prev; 1-7. ©2017 AACR.

Concepts: Metastasis, Ultraviolet, Melanoma, Melanin, Skin cancer, Sunburn, Sunscreen, Sun tanning

34

The ability to disinfect and reuse disposable N95 filtering facepiece respirators (FFRs) may be needed during a pandemic of an infectious respiratory disease such as influenza. Ultraviolet germicidal irradiation (UVGI) is one possible method for respirator disinfection. However, UV radiation degrades polymers, which presents the possibility that UVGI exposure could degrade the ability of a disposable respirator to protect the worker. To study this, we exposed both sides of material coupons and respirator straps from four models of N95 FFRs to UVGI doses from 120 to 950 J/cm(2). We then tested the particle penetration, flow resistance and the bursting strengths of the individual respirator coupon layers, and the breaking strength of the respirator straps. We found that UVGI exposure led to a small increase in particle penetration (up to 1.25%) and had little effect on the flow resistance. UVGI exposure had a more pronounced effect on the strengths of the respirator materials. At the higher UVGI doses, the strength of the layers of respirator material was substantially reduced (in some cases, by >90%). The changes in the strengths of the respirator materials varied considerably among the different models of respirators. UVGI had less of an effect on the respirator straps; a dose of 2360 J/cm(2) reduced the breaking strength of the straps by 20% to 51%. Our results suggest that UVGI could be used to effectively disinfect disposable respirators for reuse, but the maximum number of disinfection cycles will be limited by the respirator model and the UVGI dose required to inactivate the pathogen.

Concepts: Ultraviolet, Hydrogen peroxide, Materials science, Disinfectant, Hygiene, Sunburn, Respirator, Ultraviolet germicidal irradiation

31

The body gains vitamin D through both oral intake (diet/supplementation) and synthesis in skin upon exposure to ultraviolet radiation (UVR). Sun exposure is the major source for most people even though sun exposure is complex and limited by climate and culture. We aimed to quantify the sun exposure required to meet vitamin D targets year-round and determine whether this can be safely achieved in a simply defined manner in the UK as an alternative to increasing vitamin D oral intake. Data from observation (sun exposure, diet, and vitamin D status) and UVR intervention studies performed with white Caucasian adults were combined with modeled all-weather UVR climatology. Daily vitamin D effective UVR doses (all-weather) were calculated across the UK based on ten-year climatology for pre-defined lunchtime exposure regimes. Calculations then determined the time necessary to spend outdoors for the body to gain sufficient vitamin D levels for year-round needs without being sunburnt under differing exposure scenarios. Results show that, in specified conditions, white Caucasians across the UK need nine minutes of daily sunlight at lunchtime from March to September for 25(OH)D levels to remain ≥25 nmol/L throughout the winter. This assumes forearms and lower legs are exposed June-August, while in the remaining, cooler months only hands and face need be exposed. Exposing only the hands and face throughout the summer does not meet requirements.

Concepts: Vitamin D, Ultraviolet, Sun, Vitamin, United Kingdom, Sunlight, Sunburn, Sunscreen

27

This issue contains nine papers on the subject of upper-room ultraviolet germicidal irradiation (UVGI) for control of hazards to health from airborne bio-aerosols. These contributions originated from a two-day “Symposium on Upper Room UVGI - Toward International Application Guidelines” held in December, 2011 at the Harvard School of Public Health, the conclusion of a year-long, interdisciplinary research and training program on this issue, sponsored by Fogarty International. Not all of the presentations at that symposium resulted in papers, and the purpose of this instruction and overview is to put the presentations into a broader context, with comments on areas discussed, but not captured in the papers. This article is protected by copyright. All rights reserved.

Concepts: Ultraviolet, Radiobiology, All rights reserved, Hygiene, Sunburn, Debut albums, Copyright, Ultraviolet germicidal irradiation

27

Ultraviolet germicidal irradiation (UVGI) for air disinfection applications has relied on low-pressure mercury vapor lamps for decades. New design requirements have generated the need for alternatives in some uses. This paper describes the current state of UVGI technology and describes future directions for technology development, including the use of lamps produced from non-toxic materials and light-emitting diode lamps. Important applications are discussed such as the use of ultraviolet germicidal lamps in developing countries, in heating, ventilating and air-conditioning systems to improve energy efficiency and indoor air quality, and for whole room disinfection. This article is protected by copyright. All rights reserved.

Concepts: Ultraviolet, All rights reserved, Indoor air quality, HVAC, Sunburn, Copyright, Ultraviolet germicidal irradiation, Ventilation

27

Intermittent sunburns, particularly in childhood, are the strongest environmental risk factor for malignant melanoma (MM). In mice, a single neonatal ultraviolet radiation (UVR) exposure induces MM whereas chronic doses to adult mice do not. Neonatal UVR alters melanocyte migration dynamics by inducing their movement upwards out of hair follicles into the epidermis. UVR is known to induce inflammation and recruitment of macrophages into the skin. In this study we have used a liposomal clodronate strategy to deplete macrophages at the time of neonatal UVR, and shown functionally that this reduces the melanocyte proliferative response. This effect was not reproduced by depletion of CD11c-expressing populations of dendritic cells. Based on epidermal expression array data at various time points after UVR, we selected mouse strains defective in various aspects of macrophage recruitment, activation and effector functions and measured their melanocyte UVR response. We identified Ly6c(low)MHCII(hi) macrophages as the major population promoting the melanocyte response across multiple strains. The activity of this subpopulation was CCR2-independent and partly IL17-dependent. By helping induce this effect, the infiltration of specific macrophage subpopulations after sunburn may be a factor in increasing the risk of subsequent neoplastic transformation of melanocytes.Journal of Investigative Dermatology accepted article preview online, 15 January 2013; doi:10.1038/jid.2013.9.

Concepts: Cancer, Ultraviolet, Melanoma, Skin, Melanin, Sunburn, Sunscreen, Melanocyte