ultraviolet-A Rays Research Articles

Photochemical Crosslinking of Tarsal Collagen as a Treatment for Eyelid Laxity: Evaluation in Ex Vivo Human Tissue

Purpose: Experimental investigation in human eyelids to confirm that exposing excised tarsal plates to ultraviolet-A radiation can induce a stiffening effect through the riboflavin-photosensitized crosslinking of tarsal collagen. Methods: Thirteen tarsal plates excised from nonfrozen human cadavers were irradiated with ultraviolet-A rays (365 nm wavelength) at an irradiance of 75 mW/cm2 for 3 minutes, equivalent to a radiation fluence of 13.5 J/cm2, in the presence of a riboflavin derivative as a photosensitizer. The tensile stress (strength) and Young’s modulus (stiffness) of both nonirradiated and irradiated specimens were measured with the BioTester 5000 in the uniaxial mode at a strain of 10% and analyzed statistically. Individual specimens excised from 2 cadavers were also examined by routine histopathologic protocols to assess the effect of radiation on the Meibomian glands and collagen organization. Results: The irradiation enhanced both stiffness and strength of the human tarsal specimens, the difference between the test samples and controls being statistically significant (p < 0.0002 for n = 13). Histology indicated no damage to tarsal connective tissue or to Meibomian glands, and revealed a more compact packing of the collagen network located around the glands, which may be beneficial. The existence of collagen compaction was also supported by the reduction of samples’ thickness after irradiation (p = 0.0645). Conclusions: The irradiation of tarsal tissue with ultraviolet-A light of tarsus appears to be a safe and effective method for reducing eyelid laxity in human patients.

PACK-CXL sebagai Terapi Alternatif pada Ulkus Kornea

Introduction: Corneal ulcer is a leading cause of blindness worldwide. Many of these patients did not respond to conventional treatment with topical agents. Photo Activated Chromophore for Keratitis - Corneal Cross-Linking (PACK-CXL) has been suggested to treat baterial and fungal corneal ulcer that did not respond to antimicrobial agents. Purpose : To report a case series of corneal ulcer treated with PACK-CXL as adjuvant treatment Case Report: Four eyes with corneal ulcer underwent PACK-CXL with ultraviolet-A rays and transepithelial riboflavin according to Dresden procedure. Preoperative and postoperative slit lamp examination of cornea and visual acuity assessment was done. Postoperative outcome includes objective signs like improvement in epithelialization, corneal scarring and vascularization. Result: Three eyes healed completely with scarring at 1-month follow-up. One of the patients developed desematocele in 12 days. Epithelial defect completely healed over time but one underwent amniotic membrane transplant. Responed to treatment were defined by epithelialization and scar formation. Conclusion: The corneal cross-linking has a beneficial role as an adjuvant therapy for corneal ulcer. It helps in relief of pain and healing of ulcer. PACK-CXL can be a choice of adjuvant treatment if the corneal ulcer doesn't heal using topical treatment.

Effects of Ultraviolet-A Radiation on Enzymatically Degraded Tunica Adventitia of the Porcine Abdominal Aorta

In a previous study, it was demonstrated that mechanical stiffness and strength of tunica adventitia of the porcine abdominal aortic wall were significantly increased following irradiation of the tissue with ultraviolet-A (UV-A) rays, due to photochemically induced crosslinking of adventitial collagen. We have suggested that by applying the process to a dilated aortic region caused by abdominal aortic aneurysm (AAA), the mechanically enhanced adventitial layer might delay or prevent the aneurysmal rupture in human patients. Here, we extended our investigation to adventitial tissue that was subjected to in vitro collagenolysis, such mimicking a step in the aneurysmal pathomechanism. We used tissue isolated from the abdominal region of healthy porcine aortas. The adventitia was separated from the vessel wall and subjected to enzymatic degradation and exposed to UV-A radiation (365 nm) in the presence of a riboflavin derivative as the photo-initiator. Collagenolysis was carried out in buffered medium at two different durations (8 and 20 h). Three sets, each of 30 adventitial specimens (degraded only, irradiated prior to degradation, and irradiated after degradation), were evaluated in a mechanical tester. Mechanical testing of the irradiated specimens indicated an increase in both stiffness (Young’s modulus) and strength (ultimate stress) when compared to those degraded but not irradiated. The specimens first irradiated and then degraded displayed the highest gain in both stiffness and strength. In the tissue irradiated after degradation, the longer the duration of collagenolysis, the less significant was the enhancement of mechanical characteristics. Irradiation with UV-A rays of enzymatically degraded aortic adventitial tissue induced the enhancement of its mechanical characteristics (stiffness, strength). The earlier the irradiation, the more significant the enhancement.

Comparison of Corneal Stromal Demarcation Line Depth in Epi-off and Epi-on Corneal CrossLinking Using Anterior Segment Optical Coherence Tomograph

Objective: To compare the corneal stromal demarcation line depth after Epithelium-On and Epithelium-Off corneal crosslinking in patients with keratoconus using anterior segment Optical Coherence Tomography (AS-OCT).
 Study design: Quasi-experimental study.
 Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi Pakistan from Jun 2018 to Jun 2019.
 Methodology: This study included patients (60 eyes) with progressive keratoconus treated with procedure CXL (corneal cross linkage). There were 30 eyes in each group. Two different protocols of Corneal cross linkage were performed, and patients were divided into two groups according to protocol: 1) epithelium-on Corneal cross-linkage, 2) epithelium-off Corneal crosslinkage. In the First-Group, epithelium-on Corneal cross-linkage,corneal epithelium was not removed, riboflavin solution was instilled on the cornea for one hour, and the cornea was exposed to Ultraviolet A rays. In Epithelium off Corneal cross-linkage,after epithelium was removed by spatula, riboflavin solution was instilled for 30 minutes, and Ultraviolet-A rays were focused on the cornea. After one month of the procedure, Anterior segment Optical Coherence Tomography was performed.Demarcation line depth was measured in treated corneas in all patients from both groups, and findings were compared.
 Results: The stromal demarcation line depth was similar in both groups, and there was no statistical difference between the groups. The mean value of demarcation line depth was 277.13±107.09 цm (p>0.05).
 Conclusion: Corneal stromal demarcation line depth after both procedures was similar in both groups after one month of Corneal cross-linkage, so it was concluded that epithelium-on Corneal cross-linkage was comparable to epithelium-off Corneal cross-linkage.

RETRACTED ARTICLE: The assessment of the protective impact of spidroin extract against UV-A radiation damage by using earthworms (Aporrectodea caliginosa) as a robust human skin model via macroscopic and histological observations

Numerous studies have confirmed the damage caused by excessive exposure to ultraviolet-A rays. Malignant melanoma and skin cancer are two of the most serious health consequences. Thus, the UV-A protectant is intended to protect the skin, especially the two primary layers of skin (epidermis that represents the interface between the body and its surroundings and dermis). Spider silk is the most powerful natural fibre due to its regeneration, biocompatibility, antimicrobial, wound healing, antiseptic, and blood clotting properties. This work targeted to determine the protective effect of spidroin extract against UV-A radiation damage. Earthworms Aporrectodea caliginosa were collected from Assiut University’s farm. Each set of ten earthworms was separated into six groups and placed in a plastic container. Webs of spiders collected from trees and old houses. Spidroin was extracted and utilised in this work to determine the potential effects of topical application on UV-A protection. The experiment is divided into two sections: (1) UV-A exposure and (2) the use of spidroin extract to protect the earthworms from ultraviolet radiation. Two control groups (1،2) of worms were not received UV-A exposure, and four groups (3,4,5,6) were exposed to UVR-A. In contrast, groups (5,6) were received spidroin extract before exposure to UV-A. Each group from the groups (3,4,5,6) was exposed for three consecutive days (¼ hour/day, ½ hour/day, and 1 h/day), using a UV-Lamp with a wavelength of 366 nm. The histopathological changes revealed that after 1⁄4 h of UV exposure, the cuticle was swollen with a slightly detached epithelium. The cuticle was down after 1⁄2 h of exposure, and the epidermis was totally damaged and necrosed. After 1 h, the exposure showed destruction of the epidermis in the circular muscle with a loss of muscle filament integrity, varying size, and altered nucleus form, along with mild disintegration of longitudinal muscle. Spidroin extract is critical for earthworm protection against UV-A radiation damage and able to regeneration. For the first time, morphological and histological analysis was established to detect the Spidroin extract evaluated for topical application on earthworms. Earthworms can be considered as a robust human skin model prior to UV-A exposure. It induces a complete protective effect against UV-A radiation damage in earthworms.Graphical abstract

The sun is here! What will you recommend?

Spring and summer are just around the corner, and most areas accustomed to clouds and cooler temperatures will begin to experience a warming trend. This means folks will be spending more time in the sun. Pharmacists should be prepared to answer questions and make recommendations about sunscreen. Here's some important information to consider as you counsel patients on sun safety and the benefits of using sunscreen. The ultraviolet (UV) spectrum is divided into three major bands—ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC)—all of which may cause or exacerbate sun-induced skin disorders. UVA and UVB primarily are responsible for photodamage, as all UVC radiation is removed by the ozone layer. UVA and UVB both play a role in causing skin cancer. The only true therapeutic effect of UVB exposure is synthesis of vitamin D3 in the skin. Sun protection factor (SPF) is one parameter for determining a sunscreen's effectiveness for UV protection. Another parameter, minimal erythema dose, is used to calculate a sunscreen's SPF. SPF is calculated based on the time to skin burning with sunscreen compared with time to skin burning without sunscreen. For example, by using SPF 10, a person who usually stays in the sun for 10 minutes before starting to burn can prolong that time to approximately 100 minutes. Many dermatologists recommend using a product with SPF 30 or higher. Topical sunscreens can be divided into two major subgroups: chemical and physical. Chemical sunscreens absorb and thus block the transmission of UV radiation to the epidermis. Physical sunscreens are generally opaque; instead of absorbing UVR, they reflect and scatter it. Broad-spectrum sunscreens are designed to protect against both UVA and UVB rays. Many medications are associated with photosensitivity reactions. Review your patient's medication list and counsel patients to prevent any negative reactions. ▪For maximum effectiveness, apply sunscreens liberally to all sun-exposed areas of the body and reapply at least as often as the label recommends.▪Apply to dry skin at least 15 to 30 minutes before sun exposure if expecting to spend more than 20 minutes in the sun.▪Reapply every 2 hours at minimum, even on cloudy days.▪Reapply after heavy sweating, swimming, and toweling off. Reapplying doesn’t extend the length of time a person is protected from sunburn.▪When using sunscreen sprays, spray and rub into skin to ensure uniform coverage.▪If using insect repellent and sunscreen, apply sunscreen before insect repellent.▪Do not use on children younger than 6 months. Lotions are the preferred dosage form for children.▪For sufficient protection, the average adult in a bathing suit should apply nine portions of sunscreen of approximately ½ teaspoon each, or approximately 4.5 teaspoons (22.5 mL) total. Distribute the sunscreen as follows:–Face and neck (including ears): ½ teaspoon–Arms and shoulders: ½ teaspoon to each side of body–Torso: ½ teaspoon each to front and back–Legs and tops of feet: 1 teaspoon to each side of body As we consider the opportunities to counsel patients on appropriate sunscreen use, we shouldn’t assume they’re getting this advice elsewhere. Many people believe they’re knowledgeable about sunscreens and protection from the sun's harmful rays—until they get a sunburn. Because of the cost of sunscreen products and the need to apply them often and in sufficient amounts, users may apply substantially less sunscreen than is required to provide adequate protection. Find ways to educate your patients on optimal ways to protect against the potential dangers of the sun's UVA and UVB rays while still enjoying outdoor fun and activities. Shelf talkers and signage in the appropriate OTC sections of the pharmacy can facilitate dialogue. And don’t forget to practice what you preach!

3,4-dimethoxychalcone novel ultraviolet-A-protection factor in conventional sunscreen cream.

UltravioletA (UVA) rays with an intensity of 95% can induce skin cancer due to the activation of reactive oxygen species (ROS). The 3,4-dimethoxychalcone (3,4-DMC) chalcone derivative has a wide wavelength, antioxidant activity, presumed has activity as sunscreen (UVA rays). Topical delivery of water-insoluble 3,4-DMC with log P 3.84 required capable, cream formulation was chosen because it was suitable for application this chemical sunscreen. This study aims to obtain the optimal formulation of 3,4-DMC in a sunscreen cream dosage form as a UVA-protection factor (UVA-PF). This study involves experimental design. The cream 3,4-DMC was evaluated physically for 4 weeks by measuring pH, viscosity, spreadability, adhesion, centrifugation, freeze–thaw, photostability, UVA-PF used TranporeTM tape, and skin irritation test on animals. The result obtained was evaluated statistically using ANOVA (SPSS version 24). The ratio UVA/UVB value of 3,4 DMC sunscreen cream having 5 stars (*****) for all concentrations, shows the product in this study can be used as an anti-UVA agent in sunscreen cream cosmetic products. The stability of the cream has pH 4.0–4.2; spreadability 5–6 cm; viscosity 4.470–5.763; and adhesion <1 s. Freeze-thaw and centrifugation were known did not affect the stability due to the absence of separation. There was no wavelength shift in the photostability test and no skin irritation due to in vivo examination using New Zealand rabbits. The 3,4-DMC as a new agent in conventional sunscreen cream dosage form has good properties as a protection against UVA rays.

Light Stability, Pro-Apoptotic and Genotoxic Properties of Silver (I) Complexes of Metronidazole and 4-Hydroxymethylpyridine against Pancreatic Cancer Cells In Vitro.

Simple SummaryAntimicrobial properties of silver (I) ion and its complexes with metronidazole and 4-hydroxymethylpyridine are well recognized. However, little is known about its anticancer activity toward human pancreatic cancer cells. Our in vitro study revealed that silver (I) ion and its complexes with metronidazole and 4-hydroxymethylpyridine induced pancreatic cancer cells death associated with genotoxic and proapoptotic properties. In turn, the stability of active substances is of crucial importance because it determines the efficacy and applicability in clinical use. Therefore, we also evaluated photostability of silver (I) nitrate and its complexes with metronidazole and 4- hydroxymethylpyridine. Our results showed that studied complexes are more photochemically stable than silver salts, which makes them better candidates for clinical therapy.Antimicrobial properties of silver (I) ion and its complexes are well recognized. However, recent studies suggest that both silver (I) ion and its complexes possess anticancer activity associated with oxidative stress-induced apoptosis of various cancer cells. In this study, we aimed to investigate whether silver nitrate and its complexes with metronidazole and 4-hydroxymethylpyridine exert anticancer action against human pancreatic cancer cell lines (PANC-1 and 1.2B4). In the study, we compared decomposition speed for silver complexes under the influence of daylight and UV-A (ultraviolet-A) rays. We employed the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide) assay to evaluate the cytotoxicity and the alkaline comet assay to determine genotoxicity of silver nitrate and its complexes. Flow cytometry and the Annexin V-FITC/PI apoptosis detection kit were used to detect the apoptosis of human pancreatic cancer cells. We found a dose dependent decrease of both pancreatic cancer cell line viability after exposure to silver nitrate and its complexes. The flow cytometry analysis confirmed that cell death occurred mainly via apoptosis. We also documented that the studied compounds induced DNA damage. Metronidazole and 4-hydroxymethylpyridine alone did not significantly affect viability and level of DNA damage of pancreatic cancer cell lines. Complex compounds showed better stability than AgNO3, which decomposed slower than when exposed to light. UV-A significantly influences the speed of silver salt decomposition reaction. To conclude, obtained data demonstrated that silver nitrate and its complexes exerted anticancer action against human pancreatic cancer cells.

The structural characteristics of photoaging in mice caused by the effects of ultraviolet A radiation.

Due to its deep penetration into the dermis, ultraviolet A (UVA) radiation is considered a primary factor in skin photoaging. The aim of this study is to use a qualitative and quantitative analysis to determine the structural parameters of skin photoaging in mice exposed to UVA radiation, with or without the application of a photoprotective cream. The experiment consisted of the radiation of female BALBc mice in a solarium by UVA rays, up to total dosages of 7800 J/cm² and 12500J/cm². A total of 78 animals were divided into 4 experimental and 2 control groups. All animals were shaved and the animals in 2 experimental groups were treated with a photoprotective cream half an hour before exposure. The samples of the treated skin were stained with Hematoxylin-eosin and Van-Gieson staining methods. All measurements, except for the presence of dyskeratosis, were taken using ImageJ 150i software. In the study, the signs of skin photoaging were more evident in untreated groups of animals. Dysceratosis was more frequent in both of the untreated groups of animals (p=0.004) and (p=0.003). The lowest values of epidermal thickness (13.8± 2.6μm and 12.7±2.3μm) were present in both of the untreated groups of animals (p<0.001) and (p<0.001). The highest values of stratum corneum thickness (34.3±8.5μm) were observed in the untreated, shorter radiated group of animals (p<0.001) which was irradiated for the shortest period of time. Beside the control groups, the highest length of dermo-epidermal junction (DEJ) was recorded in the group of treated, longer radiated animals (1467.6±94.6μm) (p=0.373). The lowest values of dermal thickness (115.9±10.5μm and 134.8±21.8μm) and volumetric density of the collagen fibers (31.92±3.19% and 29.40±4.54%) were present in both untreated groups of animals (p<0.001), (p<0.001), (p=0.035). Skin photoaging was most pronounced in the groups of animals irradiated without the application of photoprotective cream.

Rhus coriaria L. Fruit Extract Prevents UV-A-Induced Genotoxicity and Oxidative Injury in Human Microvascular Endothelial Cells.

Rhus coriaria L. (sumac) is a small plant widely diffused in the Mediterranean region. Its fruit are often consumed as a spice but are also present in traditional medicine of several countries. Recently, interest in this plant has increased and many scientific works reported its beneficial effects including antioxidant and anti-inflammatory properties. Plant extracts can be successfully used against ultraviolet rays, which are able to reach and damage the human skin; however, sumac extracts were never applied to this usage. Thus, in this study, we used a macerated ethanol extract of Rhus coriaria L. dried fruit (mERC) to demonstrate its preventive role against the damage induced by ultraviolet-A rays (UV-A) on microvascular endothelial cells (HMEC-1). In vitro effects of the extract pre-treatment and UV-A exposure were evaluated in detail. The antioxidant capacity was assessed by reactive oxygen species (ROS) formation and cellular antioxidant activity measurement. Genoprotective effects of mERC were investigated as well. Our findings indicate that the extract acts as a cell cycle inhibitor or apoptosis inducer, according to the level of damage. The present work provides new insights into the usage of Rhus coriaria extracts against skin injuries.

Further Investigations on the Crosslinking of Tarsal Collagen as a Treatment for Eyelid Laxity: Optimizing the Procedure in Animal Tissue.

A follow-up experimental study on the exposure of animal tarsal plate to ultraviolet-A radiation aimed at establishing an optimum range for safe irradiation conditions. Sheep tarsus specimens were excised postmortem and then subjected to irradiation with ultraviolet-A rays (wavelength 365 nm) at higher irradiances than those reported in an initial study, using a laboratory radiation source. The mechanical properties (tensile strength and Young's modulus) of irradiated and nonirradiated samples were evaluated in a mechanical tester. The test and control specimens were examined histologically with an aim to assess the effects of radiation upon the meibomian glands and tarsal collagen networks, and to establish a safe range for the exposure irradiance level. As expected, irradiation induced both stiffening and strengthening of the tarsal plate specimens. At an irradiance of 50 mW/cm for 3-minute exposure, these effects were at their maximum level, after which a decline in mechanical characteristics were observed. No destruction of the tarsal connective tissue or the meibomian glands were noticed up to an irradiance of 125 mW/cm for 3-minute exposure, corresponding to a fluence of 22.5 J/cm. Histology revealed that the collagen network surrounding the glands were packed more compactly following irradiation. At a fluence of 45 J/cm, massive destruction of periglandular collagen-rich network and meibocytes were demonstrated histologically. The study indicates that irradiation of tarsal collagen leading to tissue stiffening shall be carried out at levels of fluence between 10 and 15 J/cm, a region that is deemed safe. The exposure time can be adjusted according to the surgeon's decision.Safe irradiation conditions are established for the exposure of ex vivo ovine tarsus to ultraviolet-A radiation as a potentially effective treatment for eyelid laxity in human patients.

Photochemically Induced Crosslinking of Tarsal Collagen as a Treatment for Eyelid Laxity: Assessing Potentiality in Animal Tissue.

An experimental study to demonstrate in animal eyelids that the controlled exposure of excised tarsal plate to ultraviolet-A radiation can induce a rigidification effect due to photochemical crosslinking of the constitutive collagen. Excised strips of sheep tarsus were irradiated with ultraviolet-A rays (wavelength 365 nm) at low and high irradiances, in the presence of riboflavin as a photosensitizer, using radiation sources available for corneal collagen crosslinking procedure. The tensile strength and Young's modulus (stiffness) of irradiated and control samples were measured in a mechanical tester and analyzed statistically. Histologic examination of the specimens was carried out to evaluate the effect of radiation on the meibomian glands and collagen organization. Mechanical evaluation showed that irradiation induced both stiffening and strengthening of the tarsal plate specimens, and this effect was enhanced at the higher levels of irradiance. The changes in mechanical properties can be attributed to a process of photochemically induced crosslinking of tarsal collagen. Histology revealed no changes in the meibomian glands or in the fibrous collagen system of the tarsus. These findings indicate that irradiation of tarsal collagen leading to tissue stiffening could be a safe procedure for treating lax eyelid conditions in human patients.

Intensities of Incident and Transmitted Ultraviolet-A Rays through Gafchromic Films.

Gafchromic films have been applied to X-ray dosimetry in diagnostic radiology. To correct nonuniformity errors in Gafchromic films, X-rays in the double-exposure technique can be replaced with ultraviolet (UV)-A rays. Intensities of the incident and transmitted UV-A rays were measured. However, it is unclear whether the chemical color change of Gafchromic films affects the UV-A transmission intensity. Gafchromic EBT3 films were suitable to be used in this study because non-UV protection layers are present on both sides of the film. The film is placed between UV-A ray light-emitting diodes and a probe of a UV meter. Gafchromic EBT3 films were irradiated by UV-A rays for up to 60 min. Data for analysis were obtained in the subsequent 60 min. Images from before and after UV-A irradiation were subtracted. When using 375 nm UV-A, the mean ± standard deviation (SD) of the pixel values in the subtracted image was remarkably high (11,194.15 ± 586.63). However, the UV-A transmissivity remained constant throughout the 60 min irradiation period. The mean ± SD UV-A transmission intensity was 184.48 ± 0.50 μm/cm2. Our findings demonstrate that color density changes in Gafchromic EBT3 films do not affect their UV-A transmission. Therefore, Gafchromic films were irradiated by UV-A rays as a preexposure.

Pretreatment of Ferulic Acid Protects Human Dermal Fibroblasts against Ultraviolet A Irradiation.

BackgroundApproximately 90%~99% of ultraviolet A (UVA) ray reaches the Earth's surface. The deeply penetrating UVA rays induce the formation of reactive oxygen species (ROS), which results in oxidative stress such as photoproducts, senescence, and cell death. Thus, UVA is considered a primary factor that promotes skin aging.ObjectiveResearchers investigated whether pretreatment with ferulic acid protects human dermal fibroblasts (HDFs) against UVA-induced cell damages.MethodsHDF proliferation was analyzed using the water-soluble tetrazolium salt assay. Cell cycle distribution and intracellular ROS levels were assessed by flow cytometric analysis. Senescence was evaluated using a senescence-associated β-galactosidase assay, while Gadd45α promoter activity was analyzed through a luciferase assay. The expression levels of superoxide dismutase 1 (SOD1), catalase (CAT), xeroderma pigmentosum complementation group A and C, matrix metalloproteinase 1 and 3, as well as p21 and p16 were measured using quantitative real-time polymerase chain reaction.ResultsInhibition of proliferation and cell cycle arrest were detected in cells that were irradiated with UVA only. Pretreatment with ferulic acid significantly increased the proliferation and cell cycle progression in HDFs. Moreover, ferulic acid pretreatment produced antioxidant effects such as reduced DCF intensity, and affected SOD1 and CAT mRNA expression. These effects were also demonstrated in the analysis of cell senescence, promoter activity, expression of senescent markers, and DNA repair.ConclusionThese results demonstrate that ferulic acid exerts protective effects on UVA-induced cell damages via anti-oxidant and stress-inducible cellular mechanisms in HDFs.

Enhanced permeability of ferulic acid loaded nanoemulsion based gel through skin against UVA mediated oxidative stress

The study was aimed to develop a ferulic acid (FA) loaded nanoemulsion based gel in order to ensure the enhanced permeability and maximum antioxidant activity against UVA induced oxidative stress in rat. The optimized ferulic acid loaded nanoemulsion 3 (FA-NE3) was prepared by spontaneous nano-emulsification method with an appropriate ratio (20:30:50% w/w) of the oil (isostearyl isostearate), aqueous system and Smix [surfactant (labrasol) and co-surfactant (plurol isostearique)] respectively. FA-NE3 was characterized by measuring their droplet size, zeta potential, refractive index, transmission electron microscopy (TEM), ultraviolet (UV), fourier transform infrared spectroscopy (FTIR) and rheological characteristics. Ex vivo skin permeation and in vivo UVA protection activity of FA-NE3 based nano-gels (FA-NG3) along with placebo were studied through the rat skin. FA-NE3 exhibited sustained-release profile, better permeability and ultraviolet A (UVA) protection activity as compared to conventional dosage form. This phenomenon may be attributed towards increased solubility of the drug and enhanced permeability from nanoemulsion. FA-NE3 based nanogel (FA-NG3) could elevate the level of skin marker enzymes against oxidative stress mediated by UVA. The gel formulation exhibited significant (P<0.01) skin permeability and antioxidant activity in the current investigations. The nanogel could be promising nanocarriers for topical delivery of FA in response to better skin protection activity against UVA rays in a sustained manner.

Update on ultraviolet A and B radiation generated by the sun and artificial lamps and their effects on skin.

Solar radiation, especially ultraviolet A (UVA) and ultraviolet B (UVB), can cause damage to the human body, and exposure to the radiation may vary according to the geographical location, time of year and other factors. The effects of UVA and UVB radiation on organisms range from erythema formation, through tanning and reduced synthesis of macromolecules such as collagen and elastin, to carcinogenic DNA mutations. Some studies suggest that, in addition to the radiation emitted by the sun, artificial sources of radiation, such as commercial lamps, can also generate small amounts of UVA and UVB radiation. Depending on the source intensity and on the distance from the source, this radiation can be harmful to photosensitive individuals. In healthy subjects, the evidence on the danger of this radiation is still far from conclusive.

Ascorbic acid, ultraviolet C rays, and glucose but not hyperthermia are elicitors of human β-defensin 1 mRNA in normal keratinocytes.

Hosts' innate defense systems are upregulated by antimicrobial peptide elicitors (APEs). Our aim was to investigate the effects of hyperthermia, ultraviolet A rays (UVA), and ultraviolet C rays (UVC) as well as glucose and ascorbic acid (AA) on the regulation of human β-defensin 1 (DEFB1), cathelicidin (CAMP), and interferon-γ (IFNG) genes in normal human keratinocytes (NHK). The indirect in vitro antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes of these potential APEs was tested. We found that AA is a more potent APE for DEFB1 than glucose in NHK. Glucose but not AA is an APE for CAMP. Mild hypo- (35°C) and hyperthermia (39°C) are not APEs in NHK. AA-dependent DEFB1 upregulation below 20 mM predicts in vitro antimicrobial activity as well as glucose- and AA-dependent CAMP and IFNG upregulation. UVC upregulates CAMP and DEFB1 genes but UVA only upregulates the DEFB1 gene. UVC is a previously unrecognized APE in human cells. Our results suggest that glucose upregulates CAMP in an IFN-γ-independent manner. AA is an elicitor of innate immunity that will challenge the current concept of late activation of adaptive immunity of this vitamin. These results could be useful in designing new potential drugs and devices to combat skin infections.

UV Protection Mechanism and Property of Functional Ceramic Particles

Sun protection is simply guarding a body from the adverse effects of sunlight. Aside from the hazards of heat, the sun poses the danger of sunburn, which can permanently damage the skin, precancerous changes in the skin, as well as premature wrinkling and signs of aging. UVB (Ultraviolet-B) rays are short wavelengths responsible for sun burns. UVB protection is indicated by SPF (sun protection factor) levels. UVA (Ultraviolet-A) rays penetrate deep into the skin, which can cause premature signs of aging, including sunspots, wrinkles and uneven skin tone. The PA rating system is used to indicate the level of UVA protection. In this report, the mechanism of UV protection by using titanium dioxide and zinc oxide particles are explained. Zinc oxide fine particles have excellent shielding property. We demonstrated the property using zinc oxide particles prepared by a homogeneous precipitation method from aqueous solution of zinc salts. The morphology of the zinc oxide precipitates was significantly changed depending on the precursor composition, the concentration of precipitant, and the reaction temperature. Different UV-vis absorption/reflection characteristics were observed for the particles with different morphologies.

Molecular mechanism of polypeptides from Chlamys farreri (PCF)’s anti-apoptotic effect in UVA-exposed HaCaT cells involves HSF1/HSP70, JNK, XO, iNOS and NO/ROS

This study investigated the molecular mechanisms of polypeptides from Chlamys farreri (PCF)’s anti-apoptotic effects in ultraviolet A-rays (UVA) exposed HaCaT cells. UVA-induced apoptosis in HaCaT cells was confirmed with Hoechst 33258 fluorescent staining; PCF treatment inhibited UVA-induced apoptosis in HaCaT cells, increased transcriptional activities of heat shock factor protein 1 (HSF1) and the expression of heat shock protein 70 (HSP70), whereas inhibited activation of c-Jun N-terminal kinases (JNK), expression of xanthine oxidese (XO), inducible nitric oxide synthase (iNOS) and release of nitric oxide (NO)/reactive oxygen species (ROS). Meanwhile, the HSF1 transcription inhibitor quercetin increased UVA-induced apoptosis, activation of JNK, expression of XO and iNOS and release of NO/ROS. Among the two NO release peaks we found in UVA exposed HaCaT cells, XO inhibitor oxypurinol was found to be able to inhibit NO release at 3h post UVA exposure but not 18h, while iNOS inhibitor S-methylisothiourea sulfate (SMT) was found to inhibit iNOS expression and NO release at 18h but not 3h. PCF’s protection against UVA-induced apoptosis in HaCaT cells involves increased transcriptional activity of HSF1, increased expression of HSP70, and the subsequential inhibition of JNK pathway, XO and iNOS expression and ROS/NO release.

AN OUTBREAK OF PHYTOPHOTODERMATITIS DUE TO CELERY

Celery is known to contain psoralens, a group of substances that cause a toxic dermal reaction on exposure to ultraviolet A rays (UVA). An outbreak of phytophotodermatitis amongst 11 workers in a celery harvest in southern Israel is reported. Analysis of the trigger factors was carried out. The patients were questioned regarding their working conditions. Samples of the celery that the workers had been harvesting were analyzed for levels of total psoralens by means of high performance liquid chromatography (HPLC). Levels of UVA were measured. It was found that the celery harvested in the south of the country contained 84 micrograms/g fresh weight (f.wt.) total psoralens as compared to 35 micrograms/g f.wt. in celery harvested in the north of the country at the same time. The following year the celery harvested in the south contained only 26 micrograms/g f.wt. total psoralens. Other risk factors noted were that the subjects had fair skin, wore no protective clothing, and worked with moist hands. In addition, the days were clear and sunny thus ensuring maximal UV radiation for that time of the year. Multiple factors contributed to the outbreak of phytophotodermatitis. A late harvest in the south of the country is incriminated as the cause of the unusually high levels of psoralens in the celery of that year.