• Journal of Photoscience
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• v.9 no.2
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• pp.470-471
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• 2002

It has been well documented that dermal irradiation by ultraviolet A (UVA) locally decreases the number of Langerhans cells and suppresses contact hypersensitivity of the skin. We found that topical irradiation of UVA to the eye systemically decreased the number of Langerhans cells (LC) in the dorsalskin and lymph nodes and elicited lymphocyte apoptosis in the latter tissues but not in the thymus. Optic nerve resection, but not ciliary ganglionectomy, eliminated the UVA-induced decrease in dermal Langerhans cells by a mechanism that was partially inhibited by hypophysectomy. The immunosuppressive effect of UVA was not observed in knockout mice lacking inducible-type of nitric oxide synthase (iNOS). These results suggested that topical irradiation of UVA to the eye induced immunosuppression via NO-dependet neuronal pathways.

• Toxicological Research
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• v.32 no.4
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• pp.345-351
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• 2016

Propolis is a resinous material collected by honeybees from several plant sources. This research aimed at showing its protective effect against UVA-induced apoptosis of human keratinocyte HaCaT cells. Using Hoechst staining, it was demonstrated that propolis (5 and $10{\mu}g/mL$) significantly inhibited the apoptosis of HaCaT cells induced by UVA-irradiation. Propolis also showed the protective effect against loss of mitochondrial membrane potential induced by UVA-irradiaiton in HaCaT cells. Propolis also inhibited the expression of activated caspase-3 induced by UVA-irradiation. To investigate the role of ROS in UVA-induced apoptosis and protection by propolis, the generation of ROS was determined in cells. The results showed that the generation of ROS was markedly reduced in cells pretreated with propolis. Consequently, propolis protected human keratinocyte HaCaT cells against UVA-induced apoptosis, which might be related to the reduction of ROS generation by UVA-irradiation.

• The Korean Journal of Community Living Science
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• v.14 no.3
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• pp.13-19
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• 2003

The purpose of this study was to investigate the UVA radiation protection effects of summer hats currently on the market with the purpose of making it possible to choose a hat with suitable UVA protection. Twelve different summer hats from the market were selected for the experiment. The results are summarized as follows: It is more effective to wear a hat than not wear a hat to block UVA radiation. Summer hats with the greatest degree of protection, from highest to lowest, are cotton, straw2, and straw1. In the area of the forehead, which is rarely influenced by the irradiation angle, the cotton hat was the most effective in protecting from UVA radiation because the material density was greater than that of the straw hats. A hat with a 8.5 cm brim was more effective at blocking UVA radiation on the jaw than 6 cm, 4 cm, and 0 cm wide brims, but it still couldn't block the radiation completely. Irradiation amounts at 11:00 AM on the forehead, jaw! s and left and right cheeks were lower than amounts measured on the back of the neck. This revealed that irradiation amounts depend on the shape of the hat and time of day. A hat with a brim encircling the head was found to be more effective in blocking UVA radiation than a hat with only a front or side brim.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.113-120
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• 2019

Mannosylerythritol lipids (MELs) are glycolipids and have several pharmacological efficacies. MELs also show skin-moisturizing efficacy through a yet-unknown underlying mechanism. Aquaporin-3 (AQP3) is a membrane protein that contributes to the water homeostasis of the epidermis, and decreased AQP3 expression following ultraviolet (UV)-irradiation of the skin is associated with reduced skin moisture. No previous study has examined whether the skin-moisturizing effect of MELs might act through the modulation of AQP3 expression. Here, we report for the first time that MELs ameliorate the UVA-induced downregulation of AQP3 in cultured human epidermal keratinocytes (HaCaT keratinocytes). Our results revealed that UVA irradiation decreases AQP3 expression at the protein and messenger RNA (mRNA) levels, but that MEL treatment significantly ameliorated these effects. Our mitogen-activated protein kinase inhibitor analysis revealed that phosphorylation of c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase or p38, mediates UVA-induced AQP3 downregulation, and that MEL treatment significantly suppressed the UVA-induced phosphorylation of JNK. To explore a possible mechanism, we tested whether MELs could regulate the expression of peroxidase proliferator-activated receptor gamma ($PPAR-{\gamma}$), which acts as a potent transcription factor for AQP3 expression. Interestingly, UVA irradiation significantly inhibited the mRNA expression of $PPAR-{\gamma}$ in HaCaT keratinocytes, whereas a JNK inhibitor and MELs significantly rescued this effect. Taken together, these findings suggest that MELs ameliorate UVA-induced AQP3 downregulation in HaCaT keratinocytes by suppressing JNK activation to block the decrease of $PPAR-{\gamma}$. Collectively, our findings suggest that MELs can be used as a potential ingredient that modulates AQP3 expression to improve skin moisturization following UVA irradiation-induced damage.

• YAKHAK HOEJI
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• v.51 no.4
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• pp.229-234
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• 2007

We investigated antioxidative activity of the water and ethanol extracts of leaves of Acanthopanax divaricatus var. albeofructus in human dermal fibroblast (HDFs) irradiated by UVA. The irradiation of UVA did not affect the cell viability of HDFs. The antioxidative activity of the extract was investigated by xylenol orange, TBARS (thiobarbituric acid reactive substances) and antioxidant enzyme assay. Both extracts showed H202 scavenging activity and inhibited lipid peroxidation in HDF cells irradiated by UVA. The extracts also recovered enzyme activity in the same cells.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.99-105
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• 2012

Purpose: The purpose of this study is to demonstrate inactivation effect of UVA-LED ultraviolet radiation upon Pseudomonas aeruginosa and Staphylococcus aureus which are the major bacteria causing eye diseases. Methods: The small sterilization device was made using UVA-LED of 400 nm. After Pseudomonas aeruginosa was diluted to $10^{-7}$ and Staphylococcus aureus to $10^{-5}$ and diluted solutions were put onto each liquid medium. They were irradiated by 400 nm of UVA for different amount of time; 15 min, 30 min, 60 min, 120 min, 240 min, 360 min and 480 min each. Results: The data from sterilization test was solved to regression line equation and the target log inactivation was obtained. The 3 log inactivation UV irradiation value of Pseudomonas aeruginosa was 54,847 UV dose ($mJ/cm^2$) and irradiation time was 135.42 min while the 3 log inactivation of Staphylococcus aureus was 39,066 UV dose ($mJ/cm^2$) and irradiation time was 98.72 min. Conclusions: The inactivation effect of sterilization method using 400 nm of UVA-LED upon Pseudomonas aeruginosa and Staphylococcus aureus has been verified and it is considered as a useful method in inactivating the contact lenses.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1204-1210
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• 2014

New control methods are proposed for indoor air quality by removing fine airborne dust-particles. As suspended fine dust-particles contain inorganic dust as well as fine organic bacteria, studies for simultaneous control of these contaminants are required. In this study, photocatalytic disinfection of indoor suspended microorganisms such as E. coli and Bacillus subtilis is performed by three types of photocatalysts with UVA irradiation. The UVA irradiation strength was controlled to the minimum $3{\mu}W/cm^2$, and ZnO, $TiO_2$, and ZnO/Laponite ball were used as the catalysts. The results indicate that E. coli was removed over 80 % after about 2 hours of reaction with UVA and all three types of photocatalysts, whereas only with UVA, around 50 % E. coli removal was obtained. Among the catalysts, ZnO/Laponite composite ball was found to have similar sterilizing capacity to $TiO_2$. However, in case of B. subtilis, which has thick cell wall in its spore state, disinfection was not effective under the low UVA irradiation condition, even with the catalysts. Further studies need to figure out the optimal UVA irradiation ranges as well as photocatalysts doses to control airborne dust, to provide healthy clean air environment.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.5
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• pp.275-279
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• 2002

Nerve growth factor (NGF) is an important autocrine growth factor and also a survival factor for keratinocytes. NGF may act in the hyperproliferative condition, psoriasis. Clinically, the combination of psoralen and UVA (PUVA) has been used in the treatment of a wide variety of cutaneous disorders, such as psoriasis and vitiligo. However, the precise therapeutic mechanism of PUVA on the dermatologic diseases remains unclear. The purpose of this study was to examine whether the expression of NGF in cultured keratinocytes is influenced by PUVA. Thus, normal human keratinocytes were isolated from neonatal foreskin, and the third to fifth-passaged cells were used in this study. The cells were exposed to various doses of UVA (30, 60, 120 $mJ/cm^2)$ after adding 8-methoxypsoralen (8-MOP) to examine the expression of NGF mRNA. The RNA and protein of the cells were extracted at various time points (1, 8, 24 hours) after UVA irradiation to examine the expression of NGF mRNA and production of NGF protein. In keratinocytes, there were no differences in the expression of NGF mRNA between the different doses of UVA irradiation, however, the expression of NGF mRNA in UVA and PUVA groups tended to increase as the time increased. The expression of NGF mRNA was the highest in PUVA group, followed by UVA group and the lowest in 8-MOP group. The expressions of NGF protein at 1 and 8 hours after UVA irradiation were lower in the PUVA group than in the other groups. This study showed that the expression level of NGF protein in keratinocytes was relatively lower in the PUVA groups than in the other groups, suggesting that the therapeutic mechanism of PUVA in psoriasis is related to the decrease of NGF protein.

• Journal of Photoscience
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• v.9 no.2
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• pp.500-502
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• 2002

In vitro and in vivo studies have reported the induction of matrix metaloproteinase (MMP)-1 in the fibroblasts by ultraviolet (UV) A irradiation. We constructed the skin equivalent model using HaCaT cells as keratinocytes and human neonatal dennal fibroblasts as fibroblasts in the present study. The induction of MMP-l in the fibroblasts was confirmed immunohistochemically 6 hours after UVA irradiation using this model. This model was simply composed of human keratinocytes and fibroblasts. To our knowledge, there have been a few papers concerning the skin equivalent model in the field of photobiology. The effect of UVA exposure to fibroblasts through keratinocytes was examined using this model. The cross-talk can be examined between keratinocytes and fibroblasts. This model can be a useful tool in the field of photobiology.

• 대한예방의학회:학술대회논문집
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• 1999.10a
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• pp.308-309
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• 1999