UVB Dose Research Articles

Oxyresveratrol-induced Activation of Nrf2/HO-1 Signaling Pathway Enhances Ability of Resveratrol to Inhibit UVB-induced Melanin

Abstract Objective: This study was performed to investigate the relationship between the human melanogenesis and antioxidant systems and to further confirm the synergistic effect of oxyresveratrol (OXYR) and resveratrol (RES) in human epidermal melanocyte cell line. Methods: The human epidermal melanocyte line PIG1 cells were divided into the UV groups and control group, treated with different doses of UVB and without UVB, respectively. MTT assay and flow cytometry were used to detect cell viability and apoptosis. The expression of Nrf2/HO-1 and melanogenesis-associated proteins/genes was measured by Western blotting and real-time qPCR (RT-qPCR). pCMV6-XL5-Nrf2 was used to upregulate the expression of Nrf2. Subsequently, the proteins/genes levels of Nrf2/HO-1 and tyrosinase (TYR), melanin/eumelanin content, and reactive oxygen species (ROS) were analyzed. Isobologram analysis and cell experiment were used to analyze whether OXYR and RES inhibit TYR synergistically. Western blotting, RT-qPCR, and NaOH splitting method were used to determine the Nrf2/HO-1 and melanogenesis-associated proteins/genes expression and melanin content to evaluate the efficacy of OXYR and RES. Results: The activated Nrf2 and HO-1 eliminated ROS produced by UVB irradiation. The melanogenesis-associated proteins/genes of melanocyte-inducing transcription factor (MITF, P < 0.01 on protein expression), TYR (both P < 0.01), TYR-related protein (TRP)-1 (both P < 0.05), and TRP2 (P < 0.05 on mRNA expression) were activated in PIG1 cells by UVB irradiation. Simultaneously, the upregulation of Nrf2 significantly reduced melanogenesis formation (P < 0.001) and TYR level (P < 0.01 on protein expression). Moreover, OXYR and RES synergistically inhibited TYR activity (P < 0.001) and reduced melanin content (P < 0.001). Conclusions: A microbalance exists between Nrf2/HO-1 signaling and melanogenesis production in the UVB-induced responses of melanocytes. Simultaneously, OXYR enhances the ability of RES to inhibit melanin production.

Hydroxylumisterols, Photoproducts of Pre-Vitamin D3, Protect Human Keratinocytes against UVB-Induced Damage.

Lumisterol (L3) is a stereoisomer of 7-dehydrocholesterol and is produced through the photochemical transformation of 7-dehydrocholesteol induced by high doses of UVB. L3 is enzymatically hydroxylated by CYP11A1, producing 20(OH)L3, 22(OH)L3, 20,22(OH)2L3, and 24(OH)L3. Hydroxylumisterols function as reverse agonists of the retinoic acid-related orphan receptors α and γ (RORα/γ) and can interact with the non-genomic binding site of the vitamin D receptor (VDR). These intracellular receptors are mediators of photoprotection and anti-inflammatory activity. In this study, we show that L3-hydroxyderivatives significantly increase the expression of VDR at the mRNA and protein levels in keratinocytes, both non-irradiated and after UVB irradiation. L3-hydroxyderivatives also altered mRNA and protein levels for RORα/γ in non-irradiated cells, while the expression was significantly decreased in UVB-irradiated cells. In UVB-irradiated keratinocytes, L3-hydroxyderivatives inhibited nuclear translocation of NFκB p65 by enhancing levels of IκBα in the cytosol. This anti-inflammatory activity mediated by L3-hydroxyderivatives through suppression of NFκB signaling resulted in the inhibition of the expression of UVB-induced inflammatory cytokines, including IL-17, IFN-γ, and TNF-α. The L3-hydroxyderivatives promoted differentiation of UVB-irradiated keratinocytes as determined from upregulation of the expression at the mRNA of involucrin (IVL), filaggrine (FLG), and keratin 14 (KRT14), downregulation of transglutaminase 1 (TGM1), keratins including KRT1, and KRT10, and stimulation of ILV expression at the protein level. We conclude that CYP11A1-derived hydroxylumisterols are promising photoprotective agents capable of suppressing UVB-induced inflammatory responses and restoring epidermal function through targeting the VDR and RORs.

Evaluation of skin phototoxicity of transdermally administered pharmaceuticals in Sprague-Dawley rats

Some drugs cause phototoxicity in humans when exposed to light, thus there is a need for an in vivo phototoxicity test to evaluate them. However, an in vivo phototoxicity test method to evaluate this has not been established. This study aimed to establish an in vivo phototoxicity test method for transdermally administered drugs. For this, we evaluated the phototoxicity using Sprague-Dawley (SD) rats for transdermal administered drugs and we studied the appropriate UVA dose using 8-methoxypsalen, which is a well-known phototoxic drug. We found that a UVA dose of 15 J/cm2 was dose and time dependent response compared to other UVA doses. We performed the Minimum Erythema Dose (MED) test because UVB can cause skin irritation by itself and selected 0.01 J/cm2 as an appropriate dose of UVB. Using the selected UVA and UVB doses, we performed a phototoxicity study of 6 pharmaceutical drugs, which included phototoxic and non-phototoxic drugs. As a result of the phototoxicity test, 100% accuracy was obtained when compared with previous studies. In addition, we performed histopathology to confirm the new findings. We found that histopathology can be used as an additional indicator of phototoxicity test for transdermally administered drugs.

Impact of UV radiation on plankton net community production: responses in Western Australian estuarine and coastal waters

Net community production (NCP) is a relevant parameter informing on the role of plankton communities as sinks or sources of CO2in the ocean. We assessed the effect of ultraviolet (UV) radiation on NCP in different regions along the coast of Western Australia (WA). We compared 57 NCP measurements of surface communities receiving full-spectrum natural solar radiation, to communities with natural UVB radiation excluded (NCP-UV). Very high values of incident UVB radiation were registered, especially during spring and summer (up to 75 kJ m-2d-1). Although a strong inhibitory effect of UVB on NCP was expected due to the high UVB levels, no significant differences between NCP and NCP-UVwere observed in any sampled region. However, we found a general trend of NCP inhibition by 33.4% under UVB radiation along the WA coast. While NCP of autotrophic communities tended to slightly decrease under UVB radiation, no robust pattern was observed for heterotrophic communities. Experiments measuring the response of NCP exposed to a gradient of enhanced UVB doses exhibited a UV dose-dependent inhibition of NCP in estuarine communities (i.e. higher inhibition with higher UVB doses), and a UV dose-independent inhibition in coastal communities. Ourin situdata showed that the net metabolism of surface plankton communities from the coast of WA was insignificantly affected by elevated environmental UVB radiation levels.

Abstract 1271: UV irradiation and epigenetic change in melanocyte 5-hydroxymethylcytosine

Abstract Background Melanoma is the main cause of death from skin cancer. Excessive sun exposure with resultant UV irradiation, particularly during childhood, is established as its major environmental risk factor. Epigenetics are becoming increasingly recognized as potential reversible regulators of genomic anomalies responsible for cancerous growth. Loss of DNA hydroxymethylation marks 5-hydroxymethylcytosine (5-hmC) a functionally significant epigenetic event in melanomagenesis, but whether decreased 5-hmC is driven by UV irradiation remains unknown. The aim of this study is to characterize 5-hmC levels in potential melanoma precursor lesions and cultured samples by UV irradiation in vitro. Methods 70 human skin excision cases of chronic UV exposed skin and matched controls were evaluated. In addition, discarded human foreskins were exposed to biologically relevant doses of UVB (302 nm) and UVA (365 nm) irradiation. Tissue samples were then incubated in DMEM medium and after 24 hours fixed in 10% formalin overnight and stored in 70% ethanol prior to sectioning and staining. A dual anti-5-hmC and anti-MART-1 immunohistochemical (IHC) staining protocol was performed, and resultant semiquantitative immunoreactivity scores were analyzed statistically by one-way ANOVA analysis and Bonferroni's Multiple comparisons test or unpaired T-test using GraphPad Prism version 7 (GraphPad Software, La Jolla, CA). All p-values were two-tailed, with a p<0.05 considered statistically significant. Results When comparing sun-protected versus chronically sun-exposed sites of the excision specimens, lower levels of 5-hmC immunoreactivity were noted in melanocytes of sun-protected specimens than sun-exposed samples (p = 0.017). Moreover, a more significant difference (p = 0.0053) was detected between 5-hmC staining in normal skin melanocytes versus 5-hmC loss detected in so-called “atypical melanocytic hyperplasia of sun-damaged skin” that surrounds melanomas. Finally, we sought to determine whether we could induce in vitro a UV effect on 5-hmC similar to that seen with chronic sun-damage. Significant decreased immunoreactivity for 5-hmC was observed in foreskin melanocytes after UV irradiation- a finding that replicated what we observed in patient samples containing chronically UV-altered melanocytes. Conclusions Our results suggest that UVB irradiation's effect on the epigenome may play a crucial role in the development of melanoma. Implementation of the dual staining for anti-5-hmC and anti-MART-1 may be helpful in defining melanocytes altered in the direction of melanomagenesis, and thus may serve as a practical assay in determining potential melanoma precursor fields amenable to surveillance and prophylactic therapies. Citation Format: Kevin Y. Wang, Tanja Zdravkovic, Christine Lian. UV irradiation and epigenetic change in melanocyte 5-hydroxymethylcytosine [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1271.

A new model to investigate UVB-induced cellular senescence and pigmentation in melanocytes

Ultraviolet (UV) light is known to potentially damage human skin and accelerate the skin aging process. Upon UVB exposure, melanocytes execute skin protection by increasing melanin production. Senescent cells, including senescent melanocytes, are known to accumulate in aged skin and contribute to the age-associated decline of tissue function. However, melanocyte senescence is still insufficiently explored. Here we describe a new model to investigate mechanisms of UVB-induced senescence in melanocytes and its role in photoaging. Exposure to mild and repeated doses of UVB directly influenced melanocyte proliferation, morphology and ploidy. We confirmed UVB-induced senescence with increased senescence-associated β-galactosidase positivity and changed expression of several senescence markers, including p21, p53 and Lamin B1. UVB irradiation impaired proteasome and increased autophagic activity in melanocytes, while expanding intracellular melanin content. In addition, using a co-culture system, we could confirm that senescence-associated secretory phenotype components secreted by senescent fibroblasts modulated melanogenesis. In conclusion, our new model serves as an important tool to explore UVB-induced melanocyte senescence and its involvement in photoaging and skin pigmentation.

The Difference between the Effect of Green Tea Cream and Tocopherol on Decreasing Level of Tyrosinase Enzyme and Amount of Melanin in Rattus norvegicus Exposed to UVB Rays

Introduction: Green tea and tocopherol are potent antioxidants used to treat melasma. However, whether green tea or tocopherol is superior remains unclear. Objective: To compare the effectiveness between green tea and tocopherol in decreasing the amount of melanin and tyrosinase level in wistar rats exposed to UVB rays.Methods: The experimental study took 30 male Wistar rats randomly and divided them into 3 groups. The control group (C-G) was given basic topical cream, GT-G was given green tea topical cream and TC-G was given tocopherol topical cream. All rats were exposed to UVB every Monday, Wednesday and Friday for 4 weeks, whereas topical creams were smeared every day. Topical creams smearing on the same day with UVB exposure was performed 20 minutes before exposure and 4 hours after UVB exposure. The doses of UVB were 50 mJ/cm2 in first week, 70mJ/cm2 in the second week and 80mJ/cm2 in the third and fourth weeks. The amount of melanin was measured using pixel method and the tyrosinase level was measured using ELISA.Results: Anova analysis indicates that the amount of melanin and tyrosinase level are significantly different between groups, p<0.05. Post Hoc LSD analysis indicates that the amount of melanin in GT-G and TC-G are significantly lower than that of C-G, p<0.05. The amount of melanin in GT-G is lower than that of TC-G, p<0.05. The tyrosinase level in GT-G is significantly lower than that of C-G and TC-G, p<0.05. Meanwhile, the tyrosinase level in TC-G is lower than that of C-G but insignificantly, p>0.05.� Conclusion: Green tea topical treatment is significantly capable of decreasing the amount of melanin and tyrosinase level better than tocopherol.

UV-B radiation hormesis in broccoli florets: Glucosinolates and hydroxy-cinnamates are enhanced by UV-B in florets during storage

Abstract Abiotic stresses are oxidative in nature and cause generation of reactive oxygen species (ROS) in plant bodies. Severe stresses can be harmful to the plant tissue, whereas sub-acute or lower doses of stresses could enhance or induce protective mechanisms, a biological phenomenon known as hormesis. The objective of this work was to examine the effect of hormetic as well as high doses of UV-B on the quality along with glucosinolate and hydroxy-cinnamate contents in broccoli florets during storage. An UV-B dose of 1.5 kJ m-2 was found to be hormetic from the color retention response. Color development, weight loss and respiration rate were monitored during 21 d of storage at 4 °C. The gene expression of dihomomethionine N-hydroxylase (CYP79F1), tryptophan N-hydroxylase 2 (CYP79B3), phenylalanine N-hydroxylase (CYP79A2), phenylalanine ammonia-lyase (PAL), chalcone synthase (CH) and flavanone 3-hydroxylase (F3H1) in the treated broccoli was also evaluated. The antioxidant capacity and the profiles of glucosinolates and hydroxy-cinnamates were determined for up to 14 d in broccoli florets stored at 4 °C by LC–MS. The hormetic dose of UV-B was effective in delaying the yellowing of broccoli florets. The initial respiration rate of the florets treated with the hormetic and a high dose (7.2 kJ m-2) was significantly high. The antioxidant capacity of florets was higher in UV-B treated florets relative to the control. The titers of indole-type glucosinolates and hydroxycinnamates in broccoli were significantly (p

Single and repeated low-dose UVB radiation exposures affect the visual system

The visual system is an important biological indicator of effects induced by ultraviolet (UV) radiation. However, research has extensively investigated the effects of high-dose UV radiation in a single exposure, thus, the differential of this work was to investigate the effects of UVB radiation in low doses in single and repeated exposure. Therefore, we investigated the effects of repeated exposure to environmental UVB doses (0.09 J/cm2) on the retina and optic lobes of the crab Neohelice granulata. We evaluated the reactive oxygen species (ROS) concentration, antioxidant capacity against peroxyl radicals (ACAP) levels, catalase (CAT) and glutathione S-transferase (GST) activities and lipoperoxidation (LPO) levels and performed histological analysis. The crabs were exposed to UVB radiation for 1 or 60 days, while the control group was exposed to visible light. In the retina region, increases in ROS concentration and CAT and GST activities after the single exposure were observed. After 60 days of exposure, we observed an increase in ACAP levels. In the optic lobes, we observed an increase in GST activity and a decrease in LPO levels after the single exposure. However, we observed an increase in ROS concentration after 60 days of exposure. Moreover, after 60 days of exposure, infiltrating hemocytes in the retina and disorganization in neuron cell bodies of the external medulla were observed. In this sense, single and repeated exposure to low doses of UVB radiation induced changes in oxidative status and inflammatory process in the visual system of the crab Neohelice granulata.

Endopolyploidy is a common response to UV-B stress in natural plant populations, but its magnitude may be affected by chromosome type.

Ultraviolet-B radiation (UV-B) radiation damages the DNA, cells and photosynthetic apparatus of plants. Plants commonly prevent this damage by synthetizing UV-B-protective compounds. Recent laboratory experiments in Arabidopsis and cucumber have indicated that plants can also respond to UV-B stress with endopolyploidy. Here we test the generality of this response in natural plant populations, considering their monocentric or holocentric chromosomal structure. We measured the endopolyploidy index (flow cytometry) and the concentration of UV-B-protective compounds in leaves of 12 herbaceous species (1007 individuals) from forest interiors and neighbouring clearings where they were exposed to increased UV-B radiation (103 forest + clearing populations). We then analysed the data using phylogenetic mixed models. The concentration of UV-B protectives increased with UV-B doses estimated from hemispheric photographs of the sky above sample collection sites, but the increase was more rapid in species with monocentric chromosomes. Endopolyploidy index increased with UV-B doses and with concentrations of UV-B-absorbing compounds only in species with monocentric chromosomes, while holocentric species responded negligibly. Endopolyploidy seems to be a common response to increased UV-B in monocentric plants. Low sensitivity to UV-B in holocentric species might relate to their success in high-UV-stressed habitats and corroborates the hypothesized role of holocentric chromosomes in plant terrestrialization.

Aspirin Protects Melanocytes and Keratinocytes against UVB-Induced DNA Damage In Vivo

UVR promotes skin cancer through multiple mechanisms, including induction of inflammation, oxidative stress, and DNA damage such as 8-oxoguanine and cyclobutane pyrimidine dimers. We investigated whether the anti-inflammatory activities of aspirin (acetylsalicylic acid [ASA]) could protect against UVB-induced DNA damage and skin carcinogenesis. ASA reduced UVB-induced 8-oxoguanine and cyclobutane pyrimidine dimers in Melan-A melanocytes and HaCaT keratinocytes. Skin from UVB-irradiated C57BL/6 mice receiving 0.4 mg ASA daily by gavage exhibited less inflammation, fewer sunburn cells, and reduced 8-oxoguanine lesions than skin from irradiated control animals. ASA similarly reduced UVB-induced sunburn cells, 8-oxoguanine, and cyclobutane pyrimidine dimer lesions in skin of melanoma-prone TN61R mice, and this was associated with decreased prostaglandin E2 in plasma and skin. These effects of ASA, however, did not delay melanoma onset in TN61R mice exposed to a single neonatal dose of UVB. In SKH1-E mice prone to squamous cell carcinoma, ASA reduced plasma and skin prostaglandin E2 levels and indices of UVB-induced DNA damage and delayed squamous cell carcinoma onset induced by chronic UVB. These results indicate that ASA can protect against UVB-induced inflammation in skin and reduce UVB-induced DNA damage in both melanocytes and keratinocytes. These effects translated into greater chemopreventive efficacy for UVB-induced squamous cell carcinoma than melanoma mouse models.

235 The importance of sirtuins in skin and new findings about sirt2 and its link to mechanobiology

Sirtuins (SIRTs) are a family of NAD+-dependent histone deacetylases that play a critical role in many diverse cellular processes including transcriptional signaling, gene silencing, metabolism, genomic stability, inflammation, energy, stress response and aging. The objectives of this study were to define the temporal role of SIRTs in skin by kinetically quantifying SIRT expression and to assess environmental impact by examining the response to environmental stressors via measuring the effect on energy (ATP) production and oxidative damage (ROS). Additionally, the effect on mechanical properties such as collagen production were measured. Finally, we demonstrate the importance of SIRT2 and its effect on age-induced changes in cell shape. Sirtuin expression levels by Normal Human Epidermal Keratinocytes (NHEK) were measured by RT-PCR. NHEK were exposed to low doses of UVB (10mJ/cm2). Cellular energy (ATP) production as well as oxidative damage (H2O2) were measured. Finally, the effects of SIRTs on pro-collagen type I production in Normal Human Dermal Fibroblasts (NHDF) and cell spreading by aged NHDF were measured. Temporal differences in sirtuin expression levels were observed over time. Furthermore, SIRTs were impacted by environmental stressors such as UVB exposure and ozone, resulting in differences in ATP and H2O2 production. These data show that SIRTs 1,2,3 and 6 support cellular activity necessary for skin mechanical properties such as boosting collagen production and through SIRT-2 increasing cellular-spreading in aging skin cells. SIRTs exhibit temporal expression and are sensitive to environmental stressors. We show that SIRTs are beneficial for both cellular integrity and repair activity. Therefore, supporting their activity is imperative for maintaining optimal skin cell activity.

Seasonality of allergic diseases: Real-world evidence from a nationwide population-based study.

IntroductionSeasonal variations of allergic diseases have been of great interest in clinical practice, but large‐scale epidemiological data in the real world is lacking.MethodsWe conducted a nationwide, population‐based, cross‐sectional study using the Korean National Health Insurance claims database to examine the seasonalities of allergic rhinitis (AR), asthma, allergic conjunctivitis (AC), and atopic dermatitis (AD). In addition, we investigated the correlations between the monthly patient numbers of each disease and climate factors such as daytime length, temperature, daily temperature range, humidity, solar radiation, rainfall, UVA dose, UVB dose, and PM10.ResultsThe highest seasonal variation was identified in AC, followed by AR, asthma, and AD. AR was most prevalent in September and least prevalent in July and was positively correlated with a daily temperature range. Asthma had peaked in the winter and spring and was negatively correlated with both temperature and humidity. AC had dual peaks in May and September and the valley in winter. AD was prevalent between May and August with the lowest visits in winter and positively correlated with temperature.ConclusionsWe demonstrated a clear seasonality of four allergic diseases. Korea is located in a temperate region with four distinct seasons, with 50 million people all having a single health insurance system. Therefore, our data reflects all hospital visits in Korea with the least chance for selection bias.

Interferon alpha promotes extrinsic apoptosis of keratinocytes following exposure to ultraviolet B radiation

Abstract Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by sensitivity to ultraviolet radiation (UVR). UVR can trigger cutaneous and systemic disease flares, yet mechanisms driving this are not well characterized. Type I interferons (IFNs) are expressed at higher levels at baseline in non-lesional skin of SLE patients and promote increased death of SLE keratinocytes (KCs) after UVR. The manner in which they regulate cell death after UVR is currently unknown. This study explores cell death pathways activated in KCs by type I IFNs and UVR. We treated immortalized human KCs (N/TERTs) overnight with IFNα prior to UVB exposure. Four hours post UVB, Annexin V (AV) and propidium iodide (PI) and cleaved-caspase-3 (CC3) staining were used to measure cell death via flow cytometry. IFNα significantly increased the percentage of CC3+ and AV+PI− cells compared to treatment with UVB alone. Further, IFNα treatment promoted apoptosis at a lower dose of UVB (20 mJ/cm2). Pre-treatment with RIPK1, RIPK3, or caspase-1 inhibitors had no effect on death suggesting this enhanced death does not involve necroptosis or pyroptosis. Use of a pan-caspase inhibitor or a caspase-8 inhibitor significantly reduced AV+PI− cells following IFNα and UVB treatment while treatment with a caspase-9 inhibitor did not, suggesting enhanced activation of the extrinsic apoptosis pathway. These data suggest that photosensitive responses exhibited by SLE patients are likely due to type I IFN priming of keratinocytes that sensitizes cells to undergo increased extrinsic apoptosis after minimal exposures to UVB. Continued investigation into mechanisms by which this occurs will be crucial for developing novel preventative strategies for photosensitivity.

New continuous total ozone, UV, VIS and PAR measurements at Marambio, 64° S, Antarctica

Abstract. A ground-based ultraviolet (GUV) multi-filter radiometer was set up at Marambio, 64∘ S, 56∘ W, Antarctica, in 2017. The instrument continuously measures ultraviolet (UV) radiation, visible (VIS) radiation and photosynthetically active radiation (PAR). The measurements are designed for providing high-quality long-term time series that can be used to assess the impact of global climate change in the Antarctic region. The quality assurance includes regular absolute calibrations and solar comparisons performed at Marambio and at Sodankylä, Finland. The measurements continue observations at Marambio that were performed with (Norwegian Institute for Air Re-search UV Radiometer (NILU-UV) radiometers between 2000 and 2010 as part of the Antarctic NILU-UV network. These measurements are ideally suited for assessing the effects of the ongoing stratospheric ozone recovery on the ecosystem, as the data products include information on radiation at various wavelengths ranging from UV to VIS so that changes on biologically effective radiation due to ozone can be separated from those due to other factors. Data products include total ozone, photosynthetically active radiation (PAR), visible (VIS) radiation at 555 nm, UV index, UV irradiance at 5 channels, UVB and UVA dose rate and daily dose, and biologically weighted UV dose rate and daily dose, calculated with 10 different action spectra. The data from the last 5 d and the daily maximum UV index time series are plotted and updated daily on the following web page: http://fmiarc.fmi.fi/sub_sites/GUVant/ (last access: 17 April 2020). The first 2 years of UV measurements were very different in terms of the results: for October, November and December the monthly average of daily maximum UVB dose rates were clearly higher in 2018 than in 2017. The largest difference was observed in October, when the average of daily maximum UVB dose rates was 76 and 102 µW cm−2 in 2017 and 2018, respectively. Monthly averages of the 3 months were similar in 2018, while in 2017 the monthly average of October was lower than those of November and December. The VIS and PAR time series show that daily maxima in 2018–2019 exceed those in 2017–2018 during late spring and summer (mid-November–January). The studied dataset, including daily maximum irradiances at five UV channels and one VIS channel; daily maximum UVB, UVA, and PAR dose rates; noon UVB, UVA, and PAR dose rates; noon total column ozone; and UVB and UVA daily doses, is freely accessible at https://doi.org/10.5281/zenodo.3688700 (Lakkala et al., 2019).

Experience of using an excimer lamp equipped with UVB dose control system in dermatology

Intermediate ultraviolet (UVB) therapy is considered a relatively safe method of treating skin diseases with an autoimmune component in development compared to medical drug methods, including PUVA therapy. This is due to the small depth of penetration of the rays of this wavelength range into skin, which provides a purely local effect on the human body. Excimer lamps are an alternative to the expensive excimer laser for phototherapy of psoriasis or vitiligo. However, for effective phototherapy using UVB lamps, the distance from an emitter to a patient’s skin must be considered. In this paper, we report on treatment of patients using an excimer lamp, the control unit of which is equipped with an optical system for controlling of ultraviolet radiation dose, which allows automatically calculating the time for a set UVB dose. The article describes the results of phototherapy using an excimer lamp of several cases of psoriasis, vitiligo and other forms of dermatitis with a good therapeutic and cosmetic effect. When using an excimer lamp, not a single case of exacerbation of dermatological diseases was established.

UVB Dose Optimization for Phototherapy in Vitamin D Deficiency : Profile Analysis of Vitamin D, TNF-α, Vascular Endothelial Growth Factor (VEGF) and Platelet Derived Growth Factor (PDGF) in Wistar Rats

Background : UVB radiation responsible for the most important biological effects including Vitamin D3 synthesis and inflammation. UVB radiation are absorbed by 7-dehydrocholesterol in the plasma membrane of epidermal cells resulting in production of cis-previtamin D3. In the other hand, an exposure to UVB leads to cutaneous tissue inflammation modulates by TNF-α which also increases platelet activating factor. VEGF and PDGF induced by TNF-α during wound healing, characterized with angiogenesis and reephitalization. Furthermore, vitamin D plays a role in inflammation inhibition and upregulates growth factors. However, the study of the mechanism has not yet been thoroughly investigated.
 Methods: This study uses post test only group design, subjected wistar rats divided into four groups. Control group, non irradiated with UVB, and the other three groups, treated with graded UVB dose started with 1 MED (50 mJ/cm2), 2 MED (100mJ/cm2) and 3 MED (150 mJ/cm2) and investigated at 6, 12, 24 and 48 hours post UVB irradiation.
 Result : The serum level of vitamin D, VEGF and PDGF were increasing due to UVB dose addition. The highest level was reached at 6 hours post radiation using 3 MED, which gradually decrease up to 48 hours (p =0,000). The rise of vitamin D after UVB radiation, inhibit TNF-α induction in every dose accordant UVB dose addition and the lowest level is using 3 MED at 12 hours post radiation (p =0,000). TNF-α reach its highest level at 24 hours post radiation using 1 MED, it is related with the acute phase of inflammation.
 Conclusion : This study reveal that higher UVB irradiance increases vitamin D and inhibit TNF-α which also promotes VEGF and PDGF.
 Bangladesh Journal of Medical Science Vol.19(4) 2020 p.749-754

UV-B radiation bearings on ephemeral soma in the shallow water tunicate Botryllus schlosseri.

Sedentary shallow water marine organisms acquire numerous protective mechanisms to mitigate the detrimental effects of UV radiation (UV-R). Here we investigated morphological and gene expression outcomes in colonies of the cosmopolitan ascidian Botryllus schlosseri, up to 15-days post UV-B irradiation. Astogeny in Botryllus is characterized by weekly repeating sets of asexual budding, coinciding with apoptotic elimination of functional zooids (blastogenesis). Ten UV-B doses were administered to three clusters: sublethal, enhanced-mortality, lethal (LD50=6.048kJ/m2) which differed in mortality rates, yet reflected similar distorted morphotypes, and arrested blastogenesis, all intensified in the enhanced-mortality/lethal clusters. Even the sub-lethal doses inflicted expression modifications in 8 stress proteins (HSP 90/70 families and NIMA) as well as morphological blastogenesis. The morphological/gene-expression impacts in surviving colonies lasted for 15 days post irradiation (two blastogenic-cycles), where all damaged and arrested zooids/buds were absorbed, after which the colonies returned to their normal blastogenic-cycles and gene expression profiles, and initiated new buds. The above reflects a novel colonial maintenance strategy associated with the disposable-soma tenet, where the ephemeral soma in Botryllus is eliminated without engaging with the costs of repair, whereas other colonial components, primarily the pool of totipotent stem cells, are sustained under yet unknown colonial-level regulatory cues.

Microalgae Nannochloropsis oceanica as a future new natural source of vitamin D3

For the last two decades there has been a rise in awareness about the general low dietary intake of vitamin D3. Fish have the highest natural content of vitamin D3, which is suggested to originate from zooplankton and microalgae. However there are no studies reporting which microalgal species may be the source of vitamin D3. In this study, four selected microalgal species were cultivated during exposure of artificial UVB. The effect of UVB dose on the growth and biochemical composition of the cells (vitamin D3, PUFAs and carotenoids) was evaluated. Of the four species, exclusively Nannochloropsis oceanica was able to produce vitamin D3 (up to 1 ± 0.3 µg/g DM), and production was significantly enhanced by increasing the dose of the UVB. These findings suggest that N.oceanica exposed to artificial UVB could be used as a new natural source of vitamin D3, either as direct source or through animal feed.

Dose-Response and Temperature Dependence of the Mortality of Spider Mite and Predatory Mite Eggs Caused by Daily Nighttime Ultraviolet-B Irradiation.

The two-spotted spider mite, Tetranychus urticae, is an economically important agricultural pest. A novel physical control method involving daily nighttime UV-B irradiation was recently developed for use in strawberry greenhouses. However, the overlapping of leaves after March prevents direct irradiation to T.urticae on the lower leaf surface, decreasing control effect. Excessive UV-B irradiation causes leaf sunscald in winter. Therefore, optimization of UV-B irradiance and a compensatory control agent are desired. Temperature may affect the survival of organisms exposed to UV-B, although the temperature dependence of UV-B damage is controversial. A phytoseiid mite, Neoseiulus californicus, is a prominent predator but vulnerable to a single UV-B irradiation. We compared dose-response and temperature dependence of UV-B damage between T.urticae and N.californicus eggs under daily nighttime UV-B irradiation. Unexpectedly, N.californicus showed greater resistance to UV-B than T.urticae, and the mortality was increased and decreased at low and high temperatures, respectively. This makes possible the application of UV-B doses that are lethal for spider mites but safe for phytoseiid mites. Overall, we concluded that combined use of phytoseiid mites with UV-B lamps is advantageous to spider mite management in strawberry greenhouses.