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In recent trends, radiation falls under the narrowband ultraviolet‐B region (305–315 nm) widely used in phototherapy lamp applications in the treatment of skin diseases. In this paper, we report a Gd3+‐doped NaYF4 luminescent material synthesized for the first time using the low‐temperature co‐precipitation method. It crystallized into a face‐centred cubic structure, as confirmed by X‐ray diffraction characterization techniques and Rietveld refinement. The photoluminescence property of the as‐prepared sample shows a highly intense, sharp emission band obtained at 311 nm, which belongs to the narrowband ultraviolet‐B region and corresponds to the transition of the 6P7/2→8S7/2 level of the Gd3+ ions under 272 nm excitation (8S7/2 to 6IJ). The transitions of the Gd3+ ions are detected entirely with different concentrations of Gd3+ ions. Scanning electron microscopy analysis indicated that the average particle was 288 nm. The critical distance for energy transfer was calculated to be equal to 11.5017 Å. Dipole–dipole interaction is responsible for energy transfer, as analyzed by Dexter theory. These excellent optical characteristics, together with their highly efficient and low‐cost synthesis approach, indicate that synthesized NaYF4:Gd3+ phosphors have excessive potential for phototherapeutic lamp applications. [ABSTRACT FROM AUTHOR]

Ultraviolet B (UVB) radiation causes skin injury by trigging excessive calcium influx and signaling cascades in the skin keratinocytes. The heat‐sensitive Ca2+‐permeable transient receptor potential vanilloid 3 (TRPV3) channels robustly expressed in the keratinocytes play an important role in skin barrier formation and wound healing. Here, we report that inhibition of cutaneous TRPV3 alleviates UVB radiation‐induced skin lesions. In mouse models of ear swelling and dorsal skin injury induced by a single exposure of weak UVB radiation, TRPV3 genes and proteins were upregulated in quantitative real‐time PCR and Western blot assays. In accompany with TRPV3 upregulations, the expressions of proinflammatory cytokines tumor necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6) were also increased. Knockout of the TRPV3 gene alleviates UVB‐induced ear swelling and dorsal skin inflammation. Furthermore, topical applications of two selective TRPV3 inhibitors, osthole and verbascoside, resulted in a dose‐dependent attenuation of skin inflammation and lesions. Taken together, our findings demonstrate the causative role of overactive TRPV3 channel function in the development of UVB‐induced skin injury. Therefore, topical inhibition of TRPV3 may hold potential therapy or prevention of UVB radiation‐induced skin injury.A single exposure of weak UVB radiation leads to a significant upregulation of cutaneous heat‐sensitive Ca2+ permeable TRPV3 ion channel genes and proteins in the skin. In accompany with TRPV3 upregulations, the expressions of proinflammatory cytokines tumor necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6) were also increased. Knockout or pharmacological inhibition of TRPV3 alleviates UVB‐induced ear swelling and dorsal skin inflammation. Therefore, topical inhibition of TRPV3 may hold potential therapy or prevention of UVB radiation‐induced skin injury. [ABSTRACT FROM AUTHOR]

Background: Ultraviolet (UV) radiation‐induced oxidative stress is the main cause of photodamage to the skin. Glutathione (GSH) serves important physiological functions, including scavenging oxygen‐free radicals and maintaining intracellular redox balance. γ‐glutamylcysteine (γ‐GC), as an immediate precursor of GSH and harboring antioxidant and anti‐inflammatory properties, represents an unexplored option for skin photodamage treatment. Purpose: The purpose of this study was to investigate whether γ‐GC can reduce UVB‐induced NIH‐3T3 cell damage. Methods: The experimental groups were as follows: control, UVB radiation, UVB radiation after pretreatment with γ‐GC. Cell counting kit‐8 (CCK‐8) assays were used to measure cell proliferation, flow cytometry, and immunoblotting to detect the apoptosis rate and apoptosis‐associated proteins. The levels of Reactive Oxygen Species (ROS), Superoxide Dismutase (SOD), and GSH/GSSG (oxidized GSH) were measured to assess oxidative stress. Immunoblotting and immunofluorescence were used to detect DNA damage. The members of the MAPK signaling pathways were detected by immunoblotting. Results: UVB irradiation significantly reduced cell viability and destroyed the oxidative defense system. Pretreatment with γ‐GC reduced UVB‐induced cytotoxicity, restored the oxidation defense system, and inhibited activation of the MAPK pathway. It also reduced the apoptosis rate, downregulated the levels of cleaved caspase 3 and cleaved PARP. Furthermore, pretreatment with γ‐GC reduced the accumulation of γH2AX after UVB radiation exposure, indicating that γ‐GC could protect cells from DNA damage. Conclusion: γ‐GC protected NIH‐3T3 from damage caused by UVB irradiation. The photoprotective effect of γ‐GC is mediated via strengthening the endogenous antioxidant defense system, which prevents DNA damage and inhibits the activation of the MAPK pathway. [ABSTRACT FROM AUTHOR]

Introduction: The effect of fullerene nanoemulsion on skin wrinkle repair in an animal model was evaluated using ultrasonic images processing. Methods: Wrinkles were created in C57BL6 mice during 35 days of UVB radiation. Then, to investigate the therapeutic effect of fullerene nanoemulsions, mice were divided into three groups of control, UVB radiation, and treatment with fullerene nanoemulsion. Stable fullerene nanoemulsions were prepared using shear equalization. The therapeutic effect of fullerene nanoemulsion was investigated by extracting the skin thickness and mechanical parameters. Histology studies were performed to confirm the reliability of the treatment. Results: A significant decrease was observed in the thickness of the epidermis and dermis layers (43% and 36%), Young modulus (27%), and the shear modulus (20%) of the skin on day 28 of the fullerene nanoemulsion treatment. Skin stiffness obtained by tensiometry on day 28 of the treatment showed a 48% reduction in the treatment group compared with the control group. Histological results confirmed the effect of fullerene nanoemulsions on wrinkle repair. Conclusion: The healing effect of fullerene nanoemulsion in wrinkle repair was confirmed. To study the skin repair, parameters including Young modulus, the shear modulus, and skin layer thickness can be calculated using ultrasonic images processing. [ABSTRACT FROM AUTHOR]

Objectives: At the end of a 60‐day course of narrowband UVB phototherapy, administered to individuals with early multiple sclerosis, there were changes in the relative proportions of circulating B‐cell subsets. This study investigated phototherapy‐associated changes to cytokine responses of B cells when exposed to a TLR7 ligand. Methods: PBMCs from participants of the PhoCIS (Phototherapy for Clinically Isolated Syndrome) trial taken before (day 1) and after phototherapy for 8 weeks (day 60) were incubated with, or without, the TLR7 ligand, R848, for 18 h. Production of TNF and IL‐10 in seven B‐cell subsets was examined, with cytokine responses in each individual at day 60, adjusted for responses at day 1. Paired PBMCs were from participants administered phototherapy (n = 7) or controls (n = 6). Results: At day 60, significantly fewer B cells, particularly marginal zone‐like B cells (CD27+/IgD+), from participants administered phototherapy produced TNF in response to TLR7 stimulation. When responses by seven B‐cell subsets were analysed together using multivariate methods, a phototherapy‐specific signature was observed. An increased responsiveness from day 1 to day 60 in IgM‐only memory B cells (CD27+/IgD−/IgM+) after TLR7 stimulation also predicted slower progression from CIS to MS. Phototherapy was without significant effect on B‐cell IL‐10 production. Conclusions: Reduced TNF responses after TLR7 stimulation in marginal zone‐like B cells from participants administered phototherapy suggested treatment‐associated priming effects that were detected upon subsequent polyclonal B‐cell activation. Changes in responsiveness to TLR7 stimulation also suggested that IgM‐only memory B cells may be important in conversion from CIS to MS. [ABSTRACT FROM AUTHOR]

Ultraviolet-B (UVB) irradiation causes imbalance between dermal matrix synthesis and degradation through aberrant upregulation of matrix metalloproteinases (MMPs), which leads to overall skin photoaging. We investigated the effects of extracellular vesicles (EVs) derived from human adipose-derived stem cells (HASCs) on photo-damaged human dermal fibroblasts (HDFs). EVs were isolated from conditioned media of HASCs with tangential flow filtration and characterized using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), western blotting, micro RNA (miRNA) arrays, cytokine arrays and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The effects of EVs on the UVB-irradiated HDFs were evaluated using scratch assay, ELISA and real-time PCR. Microarrays exhibited that EVs are rich in various miRNAs and proteins, and that these EV contents are linked to a broad range of biological functions, including fibroblast proliferation, UV protection, collagen biosynthesis, DNA repair and cell ageing. A scratch assay showed that HASC-EVs enhanced the migration ability of UVB-irradiated HDFs. Real-time RT-PCR and ELISA analyses revealed that the HASC-derived EVs significantly suppressed the overexpression of MMP-1, -2, -3 and -9 induced by UVB irradiation and enhanced the expression of collagen types I, II, III and V and elastin. In particular, tissue inhibitor of metalloproteinase (TIMP)-1 and transforming growth factor (TGF)-β1, which are important factors involved in MMP suppression and ECM synthesis, were upregulated in EV-treated HDFs after UVB irradiation. Overall results suggest that diverse components that are enriched in HASC-derived EVs could act as a biochemical cue for recovery from skin photoaging. [ABSTRACT FROM AUTHOR]

A UV exclusion experiment was conducted on durum wheat (Triticum durum Desf. var. Claudio) grown in pots. Plants were grown under three different radiative treatments in greenhouses covered with plastic filters: Teflon, transparent to the entire region of natural UV‐visible sunlight (TEF); polyester, transparent above 312 nm (MYL, excluding UVB) and Lee, transparent above 400 nm (LEE, excluding both UVA and UVB). Analyses have been carried out to determine the concentration of photosynthetic pigments in leaves, UV‐absorbing compounds, nitrogen and carbon in leaves, culms and spikes and proteins and gluten in grains. In particular, plants grown under UV exclusion showed a reduction in protein and dry gluten content (consequently without variation in the ratio dry gluten/protein), but at the same time, a significant increase of gluten index, which is a parameter to define the quality of gluten, was observed. The results highlighted the influence played by UV radiation on some biochemical parameters, mainly UV‐absorbing compounds, leaf nitrogen and grain protein characteristics of durum wheat cultivated under Mediterranean conditions. In particular, natural level of UV in the Mediterranean improves the characteristics of durum wheat flour important for pasta production (high dry gluten level), while the UV exclusion could improve characteristics of flour important for bread production (high gluten index). [ABSTRACT FROM AUTHOR]

Annually, more skin cancer cases are diagnosed than the collective incidence of the colon, lung, breast, and prostate cancer. Persistent contact with sunlight is a primary cause for all the skin malignancies. UVB radiation induces reactive oxygen species ( ROS) production in the skin which eventually leads to DNA damage and mutation. Various delivery approaches for the skin cancer treatment/prevention have been evolving and are directed toward improvements in terms of delivery modes, therapeutic agents, and site-specificity of therapeutics delivery. The effective chemoprevention activity achieved is based on the efficiency of the delivery system used and the amount of the therapeutic molecule deposited in the skin. In this article, we have discussed different studies performed specifically for the chemoprevention of UVB-induced skin cancer. Ultra-flexible nanocarriers, transethosomes nanocarriers, silica nanoparticles, silver nanoparticles, nanocapsule suspensions, microemulsion, nanoemulsion, and polymeric nanoparticles which have been used so far to deliver the desired drug molecule for preventing the UVB-induced skin cancer. [ABSTRACT FROM AUTHOR]

Plants recruit microbial communities from the soil in which they germinate. Our understanding of the recruitment process and the factors affecting it is still limited for most microbial taxa. We analysed several factors potentially affecting root microbiome structure – the importance of geographic location of natural populations, the microbiome of native seeds as putative source of colonization and the effect of a plant's response to UVB exposure on root colonization of highly abundant species. The microbiome of Nicotiana attenuata seeds was determined by a culture-dependent and culture-independent approach, and the root microbiome of natural N. attenuata populations from five different locations was analysed using 454-pyrosequencing. To specifically address the influence of UVB light on root colonization by Deinococcus, a genus abundant and consistently present in N. attenuata roots, transgenic lines impaired in UVB perception (irUVR8) and response (irCHAL) were investigated in a microcosm experiment with/without UVB supplementation using a synthetic bacterial community. The seed microbiome analysis indicated that N. attenuata seeds are sterile. Alpha and beta diversities of native root bacterial communities differed significantly between soil and root, while location had only a significant effect on the fungal but not the bacterial root communities. With UVB supplementation, root colonization of Deinococcus increased in wild type, but decreased in irUVR8 and irCHAL plants compared to nontreated plants. Our results suggest that N. attenuata recruits a core root microbiome exclusively from soil, with fungal root colonization being less selective than bacterial colonization. Root colonization by Deinococcus depends on the plant's response to UVB. [ABSTRACT FROM AUTHOR]

Aim Stratospheric ozone depletion and simultaneous increases in UVB radiation due to human activities have the potential to affect freshwater biota. The goal of our study is to summarize the impacts of UVB on freshwater biota by comparing the differences in the general patterns, including the directions and the magnitudes of the impacts of UVB on four major freshwater taxa (phytoplankton, zooplankton, fish and amphibians). The potential driving forces for these differences are also explored. Location Global. Methods We performed a meta-analysis on a database consisting of 146 studies including 127 species from four taxonomic groups. We tested for the effects of taxonomic group, experimental venue, developmental stage, UVB dosage and the latitude of organism provenance. Results UVB had significant negative effects on freshwater biota from the molecular-cellular to individual-population levels. However, these effects were highly variable among the taxonomic groups. In general, zooplankton was the most negatively affected group, whereas fish and amphibians were less affected. As direct fitness components, survival and reproduction were the two responses most affected by UVB. The sensitivities of individuals to UVB at different developmental stages were different for the same taxon, while the stage-dependent sensitivity patterns also differed among different taxa. Additionally, effects of different experimental venues, UVB dosages and latitudes of organism provenance on the effects of UVB were detected. Main conclusions Our results suggest that UVB has significant negative effects on freshwater biota. We found that the effects of UVB varied among taxonomic groups, developmental stages, experimental venues, UVB dosages and latitudes of organism provenance. The variation in sensitivity among the different taxa has important implications for ecosystem responses. Given that stratospheric ozone is unlikely to recover to the levels of the 1980s in the upcoming decades, more conservation efforts should be taken to protect freshwater habitats from further damage by UVB. [ABSTRACT FROM AUTHOR]

Background Mesenchymal stem cells ( MSCs) are promising therapeutic agents for various diseases. Aims To investigate the effects of conditioned medium from human bone marrow-derived mesenchymal stem cells ( MSC-CdM) on pro-collagen production and wrinkle formation, we performed in vitro and in vivo experiments. Methods We assessed the effects of MSC-CdM on proliferation and photo-aging in human dermal fibroblasts after UVB exposure using enzyme activity assays for collagen type I secretion and MMP-1. To determine the effect of topically applied MSC-CdM on wrinkle formation, MSC-CdM (1% and 10%) and vehicle (propylene glycol: ethanol, 7 : 3) were applied to the dorsal skin of UVB-irradiated hairless mice for 8 weeks. We examined the effects on wrinkle formation by assessing visual skin grading, replica, tape stripping, transepidermal water loss ( TEWL), and skin hydration measurement. We also examined histology of the lesions using hematoxylin-eosin, Masson's trichrome, and immunohistochemical staining. Results MSC-CdM markedly reduced UV-induced matrix metalloproteinase-1 expression and increased pro-collagen synthesis in a dose-dependent manner. Our findings suggest that MSC-CdM induces repair of dermal damage and effacement of wrinkles on UVB-irradiated hairless mice through protective effect of hydration. Conclusion These results support an anti-wrinkle effect of MSC-CdM that involves increased collagen synthesis and suggest that MSC-CdM might be a potential candidate for preventing UV-induced skin damage. [ABSTRACT FROM AUTHOR]

Exposure to ultraviolet B (UVB; 280-320 nm) radiation induces the formation of reactive oxygen species (ROS) in the biological system. In this study, we examined the protective effect of carvacrol on UVB-induced lipid peroxidation and oxidative DNA damage with reference to alterations in cellular antioxidant status in human lymphocytes. A series of in vitro assays (hydroxyl radical, superoxide, nitric oxide, DPPH (2,2-Diphenyl-1-picryl hydrazyl), and ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assays) demonstrate antioxidant property of carvacrol in our study. UVB exposure significantly increased thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LHPs), % tail DNA and tail moment; decreased % cell viability and antioxidant status in UVB-irradiated lymphocytes. Treatment with carvacrol 30min prior to UVB-exposure resulted in a significant decline of TBARS, LHP, % tail DNA, and tail moment and increased % cell viability as carvacrol concentration increased. UVB irradiated lymphocytes with carvacrol alone (at 10 μg/mL) gave no significant change in cell viability, TBARS, LHP, % tail DNA, and tail moment when compared with normal lymphocytes. On the basis of our results, we conclude that carvacrol, a dietary antioxidant, mediates its protective effect through modulation of UVB-induced ROS. [ABSTRACT FROM AUTHOR]

Many amphibian species are dependent on ex situ conservation interventions for their long-term persistence. However, projects have been jeopardised by husbandry issues involving poor calcium metabolism and nutritional metabolic bone disease ( NMBD). Healthy calcium metabolism requires appropriate dietary calcium content and access to vitamin D3. In many animals, vitamin D3 can be photobiosynthesised in skin exposed to UVB radiation, as well as extracted from the diet, but the extent of vitamin D3 photobiosynthesis in amphibians is poorly known. Additionally, prey insects for captive amphibians are deficient in calcium and calcium content must be artificially increased, but the effects of different levels of augmentation and their interaction with UVB exposure are also little understood. We fed captive fire-bellied toads ( Bombina orientalis) with crickets augmented to contain 5% and 10% calcium and housed them with and without UVB exposure. Despite additional dietary vitamin D3 supplementation, we found that toads exposed to UVB radiation exhibited significantly higher serum vitamin D3 levels, indicating that this species may partly rely on photobiosynthesis sources of vitamin D3. These data are the first to show a direct link between UVB exposure and serum vitamin D3 in an amphibian. We found significant positive effects of UVB exposure and 10% dietary calcium content on skeletal structure, as well as complex interactions between treatments. We also found UVB radiation exposure resulted in more rapid natural coloration acquisition. Together, this indicates that standard calcium plus vitamin D3 supplementation methods may not fully substitute for UVB exposure and for increased feeder insect calcium content. This may have implications for the success of ex situ amphibian conservation, as well as for the welfare of captive amphibians in general. Our data lend support for the provision of UVB radiation for captive, basking amphibians. [ABSTRACT FROM AUTHOR]

Ultraviolet radiation ( UVR), in particular the UVB spectrum, is a risk factor for skin cancer development. The generation and accumulation of UVB-induced genetic mutations are fundamental premalignant events. Keratinocyte interactions between other cutaneous cell populations and the surrounding microenvironment determine cell fate and acute photoresponses. In this study, the importance of the insulin-like growth factor ( IGF) system, in particular the insulin-like growth factor-I ( IGF-I), on influencing key processes in the keratinocyte acute photoresponse was investigated. Exogenous IGF-I and other growth factors present in dermal fibroblast-conditioned media ( CM) were found to significantly enhance keratinocyte survival following UVB irradiation in vitro. This pretreatment was also shown to cause a shift in the expression levels of various DNA damage response proteins. Consequently, this was associated with accelerated rates of UVB-induced cyclobutane pyrimidine dimer removal in these samples. Finally, activation of the IGF system influenced cell cycle progression in UVB-irradiated keratinocytes. Taken together, these results highlight the importance of the IGF signalling network in initiating the repair of potentially mutagenic DNA damage in human keratinocytes. The dysregulation of these processes may therefore have significant implications in the aetiology of skin cancers and other cutaneous diseases. [ABSTRACT FROM AUTHOR]

Aim The emission of chlorofluorocarbon compounds eroded the ozone layer, raising incident ultraviolet B radiation to levels that affect biota. However, the role of UVB radiation (280-315 nm), which remains elevated to date, as a possible driver of the widespread global deterioration of marine ecosystems has not yet been fully quantified. In this paper we assess the magnitude of the impacts of elevated UVB radiation and evaluate the relative sensitivity to UVB across marine taxa and processes. Location The analyses presented are based on 1784 experimental assessments of the impacts of UVB performed with natural radiation and organisms from different geographical areas, as well as with artificial radiation and cultured organisms at many laboratories around the world. Methods First we compiled the published literature concerning experimental evaluation of the impacts of UVB on marine biota. Then a meta-analysis was conducted with the data set obtained to evaluate the responses of marine organisms and processes to enhanced and reduced UVB levels. Results Increased UVB radiation leads to a sharp increase in mortality rates across marine taxa, with protists, corals, crustaceans and fish eggs and larvae being most sensitive. A general relationship between relative changes in UVB doses and mortality rates was developed. This relationship can help assess the effects of changes in incident UVB radiation (past, present or future) on marine organisms. Main conclusions This meta-analysis demonstrates that mortality rates of marine biota increase rapidly in response to elevated UVB radiation. The enhanced mortality rates associated with currently elevated UVB levels may represent a major threat to marine biota, possibly underlying recent widespread declines in the abundance of marine organisms ranging from corals to fish and krill. [ABSTRACT FROM AUTHOR]

Ultraviolet-screening capacity of macrothalli from marine chlorophytes was analyzed using an in vivo technique based on chl fluorescence. The method, originally introduced to assess epidermal UV transmittance in leaves from higher plants, is extended to macroalgae. Validation of the method was obtained by measuring unprotected samples (i.e., isolated chloroplasts from six algal species). It is shown that in a total of 71 investigated green macroalgae, including cultured and field-collected material from six systematic orders, only 40% or 60% displayed significant screening of ultraviolet-A (UVA) or ultraviolet-B (UVB) radiation, respectively. Generally, the extent of screening was low in most of these species. Data analysis resulted in a clear phylogenetic pattern with minor influence of climatic origin of a given species. For some species, comparison between field-collected and culture-grown samples was possible. Only in 11 of 25 species field collected algae had appreciably higher screening than those grown in the absence of UVB radiation. For the first time, very efficient UVA and UVB screening is demonstrated for the order of the Cladophorales. Their UVB-screening potential varied between 40% and 85% of incoming UVB radiation. However, the nature and localization of the detected UV-absorbing compounds are still unknown. Long-term UV-exposure experiments pointed to a negative correlation of UVB-screening capacity and UV-induced inhibition of photosynthetic efficiency. Thus, species with pronounced screening were more UV resistant than species with lower screening. [ABSTRACT FROM AUTHOR]

Please cite this paper as: The role of ultraviolet radiation in melanomagenesis. Experimental Dermatology 2010; 19: 81–88. The role of ultraviolet radiation (UV) in the pathogenesis has been discussed controversially for many decades. Studies in mice (SCID, HGF/SF, SV40T) which develop malignant melanoma, show a role of UVB in melanomagenesis. In contrast to this, the role of UVA is less clear. We will review the recent in vitro and in vivo data in support of the hypothesis that UVA is also involved in the development of malignant melanoma. The role of UVA in p53 activation, apoptosis, cell cycle arrest and photoproduct formation is discussed. [ABSTRACT FROM AUTHOR]

Depletion of stratospheric ozone since the mid 1970s has led to significant increases in ultraviolet B (UVB) irradiation over Antarctica. The detrimental effects of UVB on plants are many, but plants produce photoprotective flavonoids that reduce cellular damage. We used herbarium samples of the moss Bryum argenteum collected in Antarctica to compare the levels of flavone aglycones in plants collected before and after the formation of the ozone hole. The interpretation of historical data is difficult, because environmental conditions immediately before sample collection are unknown. Factors such as cloud cover can have a significant influence on UVB dose at ground level, modifying the flavonoid content of the specimen and adding considerable variability to the results. Nevertheless, our results revealed significant relationships between total flavone concentration and pooled year classes ( P= 0.001). Furthermore, regression analysis showed a significant negative relationship of total flavone concentration and the level of ozone immediately before the time of collection ( P= 0.016). In addition, the ratio of luteolin (an ortho-dihydroxylated flavone) to apigenin (a monohydroxylated flavone) increased significantly with several environmental parameters. These included (a) increasing modelled midday UVB radiation ( P= 0.002), (b) increasing modelled midday UVB/PAR ratio ( P < 0.001), and (c) decreasing ozone concentration ( P < 0.001). We emphasise the utility of this ratio in interpreting the historical ozone trends rather than relying on changes in total flavone concentrations alone. These results illustrate that herbarium specimens may reveal historical levels of UVB radiation. [ABSTRACT FROM AUTHOR]

Human alterations to natural systems have resulted in a loss of biological diversity around the world. Amphibian population losses have been more severe than those of birds and mammals. Amphibian population declines are likely due to many factors including habitat loss, disease, contaminants, introduced species and ultraviolet-B (UVB) radiation. The effect of UVB, however, varies widely among species and can vary within populations of the same species or at different life-history stages. This variation has often led to opposing conclusions about how UVB affects amphibians. We used meta-analysis techniques to explore the overall effects of UVB radiation on survival in amphibians. We also used recently developed factorial meta-analytic techniques to quantify potential interactions between UVB radiation and other stressors on amphibians. Ultraviolet-B radiation reduced survival of amphibians by 1.9-fold compared with shielded controls. Larvae were more susceptible to damage from UVB radiation compared with embryos, and salamanders were more susceptible compared with frogs and toads. Furthermore, UVB radiation interacted synergistically with other environmental stressors and resulted in greater than additive effects on survival when 2 stressors were present. Our results suggest that UVB radiation is an important stressor in amphibians, particularly in light of potential synergisms between UVB and other stressors in amphibian habitats. [ABSTRACT FROM AUTHOR]

Background: An extract of the tropical fern Polypodium leucotomos (PL) administered orally to mice inhibits ultraviolet B (UVB) radiation-induced skin cancer formation. UVB-induced murine skin cancers occur, in part, because of UVB-induced immunosuppression. Thus, we examined whether PL inhibits UVB-suppression of the induction of contact hypersensitivity (CHS) locally or systemically. Methods: C57BL/6 mice received standard drinking water or water-containing PL. In the local model, mice were shaved on the dorsum and exposed to 3500 J/m2 of UVB radiation daily for 4 days. Control mice were not irradiated. After the last irradiation they were sensitized to oxazolone topically at the irradiated site. To examine the ability of PL to inhibit systemic UVB-induced immunosuppression, mice were given 10 000 J/m2 of UVB radiation once and immunized at a non-exposed site 3 days later. Six days after immunization (in both models), mice were challenged on the ears with oxazolone and 24/48 h ear swelling assessed. Results: PL in drinking water significantly reduced the inhibition of CHS observed with exposure to UVB radiation in both the local and systemic models. Conclusions: The ability of PL to inhibit UVB radiation-induced immune suppression may explain, in part, its ability to inhibit UVR-induced skin cancer induction in mice. [ABSTRACT FROM AUTHOR]

The article presents a research that measures the ultraviolet B erythermal solar irradiance (UVER) in Valencia, Spain from June 2003 to June 2005. In the study, the solar radiation of the UVER on the region's horizontal plane has been compared to the global irradiances. UV has been measured using a TUVR Eppley radiometer with spectral response between 290 and 385 nm as well as a Kipp and Zonen model Cm-6 broadband radiometer. Results revealed that during an average day, the highest value was 4.1 for the UVER (A+B).

The effects of enhanced UVB radiation and drought stress on willow secondary phenolics were studied using the leaves of 8-week-old micropropagated plantlets from interspecific hybrids ( Salix myrsinites L. × S. myrsinifolia Salisb.) and pure species ( S. myrsinifolia). The plantlets were subjected for 4 weeks to two levels of UVB radiation (ambient, enhanced) and two levels of watering (well-watered, drought-stressed) according to a 2 × 2 factorial design. Enhanced UVB radiation increased the total concentration of flavonoids and phenolic acids in all plantlets, while the total concentration of salicylates remained unaffected. Drought stress reduced the total concentration of salicylates and phenolic acids in S. myrsinifolia plantlets, while in hybrids only phenolic acids were affected. The response of phenolic acids to enhanced UVB in drought-stressed plantlets was different from that in well-watered ones, indicating that drought stress limited the accumulation of phenolic acids under enhanced UVB radiation. Flavonoids increased in response to enhanced UVB radiation in drought-stressed plantlets, although drought caused serious physiological stress on growth. There were significant differences between hybrid and S. myrsinifolia plantlets with respect to the composition of phenolics and between families and clones with respect to their concentration. In addition, the response of salicylates, flavonoids and phenolic acids to enhanced UVB and drought stress was clone-specific, which may indicate that climatic changes will alter the genetic composition of northern forests. [ABSTRACT FROM AUTHOR]

The effects of high PAR (400–700 nm), UVA (315–400 nm), and UVB (280–315 nm) radiation on viability and photosynthesis were investigated for Chaetoceros brevis Schütt. This Antarctic marine diatom was cultivated under low, medium, and high irradiance and nitrate, phosphate, silicate, and iron limitation before exposure to a simulated surface irradiance (SSI) treatment, with and without UVB radiation. Light-harvesting and protective pigment composition and PSII parameters were determined before SSI exposure, whereas viability was measured by flow cytometry in combination with a viability stain after the treatment. Recovery of PSII efficiency was measured after 20 h in dim light in a separate experiment. In addition, low and high irradiance acclimated cells were exposed outdoors for 4 h to assess the effects of natural PAR, UVA, and UVB on viability. Low irradiance acclimated cells were particularly sensitive to photo induced viability loss, whereas no viability loss was found after acclimation to high irradiance. Furthermore, nutrient limitation reduced sensitivity to photo induced viability loss, relative to nutrient replete conditions. No additional viability loss was found after UVB exposure. Sunlight exposed cells showed no additional UVB effect on viability, whereas UVA and PAR significantly reduced the viability of low irradiance acclimated cells. Recovery of PSII function was nearly complete in cultures that survived the light treatments. Increased resistance to high irradiance coincided with an increased ratio between protective- and light-harvesting pigments before the SSI treatment, demonstrating the importance of nonphotochemical quenching by diatoxanthin for survival of near-surface irradiance. We conclude that a sudden transfer to high irradiance can be fatal for low irradiance acclimated C. brevis. [ABSTRACT FROM AUTHOR]

Lehmann B, Querings K, Reichrath J. Vitamin D and skin: new aspects for dermatology.Exp Dermatol 2004: 13 (Suppl. 4): 11–15.© Blackwell Munksgaard, 2004It has been shown that epidermal keratinocytes have the capacity for the UVB-induced photochemical conversion of 7-dehydrocholesterol to vitaminD3, and also for the enzymatically controlled hydroxylation of the photolysis product. This metabolic loop results in the formation of the biologically active final product 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3, calcitriol). The epidermal synthesis of calcitriol is of fundamental relevance because calcitriol regulates important cellular functions in keratinocytes and immunocompetent cells. Because of their anti-proliferative and prodifferentiating effects, calcitriol and other vitamin D analogs are highly efficient in the treatment of psoriasis vulgaris. In addition, the known therapeutic effect of UVB light therapy in the treatment of psoriasis may, at least in part, be mediated via UVB-induced synthesis of calcitriol. Increasing evidence now indicates that cutaneous vitamin D synthesis is of great importance for the prevention of a broad variety of diseases, including various malignancies. It has been postulated that cancer mortality could be reduced via careful UV exposure or, more safely, via oral substitution with vitamin D. These new findings must be taken into account when establishing new sun protection guidelines for the prevention of skin cancer. In addition, better understanding of the metabolism of vitamin D in the skin has opened up new perspectives for the therapeutic application of vitamin D analogs, e.g. in inflammatory skin diseases. [ABSTRACT FROM AUTHOR]

AbstractWe report a 13-year-old boy suffering from severe ichthyosis linearis circumflexa. Evidence of hair shaft abnormalities and impaired immunity could not be found. The patient was treated with salt water baths and artificial UVB radiation (balneophototherapy) 3–5 times weekly. After 40 treatments with balneophototherapy the skin lesions were almost completely cleared and maintenance UVB monotherapy was performed twice weekly for 2 months. After 4 months, however, the disease relapsed. Balneophototherapy presents a potentially effective and well tolerated phototherapeutic option for ichthyosis linearis circumflexa. As only short periods of remission may be expected, intermittent balneophototherapy would be probably necessary to control the disease. [ABSTRACT FROM AUTHOR]

The present study, we investigate the preventive role of naringin, a dietary flavonoid, against ultraviolet‐B (UVB) radiation (280‐320 nm) induced oxidative damage and inflammatory responses in mouse embryonic fibroblast cell lines (NIH‐3T3). In this study, 20 mJ/cm 2 of UVB radiation induces cell cytotoxicity, reactive oxygen species (ROS) generation, DNA damage, and antioxidants depletion in NIH‐3T3 cells. Treatment with naringin (60 µM) prior UVB exposure prevented the cell cytotoxicity, ROS generation, DNA damage, and antioxidants depletion in NIH‐3T3 cells. Furthermore, naringin prevents UVB‐induced mitogen‐activated protein kinase families and nuclear factor‐κB (NF‐κB)‐mediated activation of inflammatory factors, that is TNF‐α, IL‐6, IL‐10, and COX‐2 in NIH‐3T3 cells. Peroxisome proliferator‐activated receptor γ (PPARγ) is an anti‐inflammatory agent and it suppressed the UVB‐mediated oxidative and inflammatory responses. In this study, naringin activates PPARγ and prevents inflammatory biomarkers in NIH‐3T3 cells. Thus, naringin prevents UVB‐mediated inflammation and oxidative damage in NIH‐3T3 cells probably over controlling NF‐κB expression and activation of PPARγ. Naringin prevents UVB radiation induced oxidative and inflammatory responses in NIH‐3T3 cells. Naringin, a bioflavonoid prevents UVB radiation induced ROS in NIH‐3T3 cells. Further, PPARγ is an anti‐inflammatory agents and it suppressed the UVB mediated oxidative and inflammatory responses. Naringin activates PPARγ and prevents MAPKs, NF‐κB and inflammatory biomarkers in NIH‐3T3 cells. Thus, naringin prevents UVB mediated inflammation and oxidative damage in NIH 3T3 cells probably activation of PPARγ. [ABSTRACT FROM AUTHOR]