Showing papers in "Photodermatology, Photoimmunology and Photomedicine in 2003"

Photoaging in Asians

Abstract: The aging process of the skin can be divided into intrinsic and photoaging. Clinically, naturally aged skin is smooth, pale and finely wrinkled. In contrast, photoaged skin is coarsely wrinkled and associated with dyspigmentation and telangiectasia. Although the population of Asia is more than half the population of the Earth, no well-designed study has been undertaken to investigate the characteristics of cutaneous photodamage in Asian skin. As Asian skin is more pigmented, the acute and chronic cutaneous responses to UV irradiation seen in brown skin differ from those in white skin. The clinical characteristics of photoaging in Asian skin, such as pigmentary changes and wrinkle patterns, differ from those of Caucasian skin. This review provides an outline of the characteristic features of photoaging on the brown skin of Asians.

Cutaneous effects of infrared radiation: from clinical observations to molecular response mechanisms

Abstract: Human skin is exposed to infrared (IR) radiation (760 nm–1 mm) from natural as well as artificial sources that are increasingly used for cosmetic or medical purposes. Epidemiological data and clinical observations, however, indicate that IR radiation cannot be considered as totally innocuous to human skin. In particular, IR radiation, similar to ultraviolet radiation, seems to be involved in photoaging and potentially also in photocarcinogenesis. The molecular consequences resulting from IR exposure are virtually unknown. Recent studies, however, have begun to shed light on the basic molecular processes such as cellular signal transduction and gene expression triggered by exposure to IR radiation. In response to IR irradiation, mitogen-activated protein kinase signaling pathways were activated mediating the upregulation of matrix metalloproteinase-1 expression. This previously unrecognized molecular ‘IR response’ shows that IR radiation is capable of specifically interfering with cellular functions and provides a molecular basis for biological effects of IR on human skin.

Photochemoprevention of skin cancer by botanical agents.

Abstract: Photochemoprevention has become an important armamentarium in the fight against ultraviolet radiation (UVR)-induced damage to the skin. Among many UVR-induced damages, skin cancer is of the greatest concern as its rates have been steadily increasing in recent years and the same trend is expected to continue in the future. Ultraviolet radiation increases oxidative stress in skin cells by causing excessive generation of reactive oxygen species (ROS), leading to cancer initiation and promotion. Antioxidants have the capability to quench these ROS and much recent work shows that some of these can inhibit many UVR-induced signal transduction pathways. Thus, identifying nontoxic strong antioxidants - capable of preventing UVR-induced skin cancer - has become an important area of research. The use of botanical antioxidants in skin care products is growing in popularity. A wide range of such agents has been shown to prevent skin cancer in animal model systems. New agents are constantly being investigated; however, only a few have been tested for their efficacy in humans. Animal model and cell culture studies have clarified that antioxidants act by several mechanisms at various stages of skin carcinogenesis. This review focuses on skin cancer photochemopreventive effects of selected botanical antioxidants.

Topical 5-aminolaevulinic acid photodynamic therapy for cutaneous lesions: outcome and comparison of light sources

Abstract: Background: Topical 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) is increasingly used for superficial non-melanoma skin cancers and their precursors. Methods: We report our 3-year experience of topical ALA-PDT, with a preliminary comparison of the effects of broadband and laser light sources. Results: We performed 688 treatments on 483 lesions in 207 patients. Complete clearance was achieved in 222/239 lesions of Bowen's disease (BD), superfi-cial basal cell carcinoma (sBCC) and actinic keratosis (AK) (93%) – 117/129 BD (91%), 84/87 sBCC (97%) and 21/23 AK (91%), with a median follow up of 48 weeks. Broadband and laser light sources were of similar efficacy. Recurrences have occurred in 10.3% BD, 4.8% sBCC and 4.8% AK. Adverse effects from PDT were uncommon but included pig-mentary change (2%) and minor scarring (2%). How-ever, severe pain was experienced in 16–21% of treatments using the high-output broadband and laser sources, but in only 2% with the low-output xenon arc source. Conclusion: Topical ALA-PDT is effective for BD, sBCC and AK and has been an invaluable addition to our dermatology service. Efficacy is similar for broadband and laser light sources, although treatment at higher surface irradiance may be painful, and excellent cosmetic results can be achieved.

Immediate effects of UV radiation on the skin: modification by an antioxidant complex containing carotenoids

Abstract: Background/Aims: The ultraviolet (UV) portion of sunlight is involved in the induction and development of skin cancers against which a limited photoprotection may be provided by reduced time of exposure, clothing, and sunscreen applications. The concept of an effective, safe, systemic photoprotection will circumvent many of the shortcomings. The UV-induced oxidative stress is a cause of DNA damage and a few publications have shown, in humans, minimal benefits, if any, of the oral intake of antioxidant complex, contrasting with the large literature showing beneficial effects in vitro or in animal models. Methods: We investigated, in 25 healthy individuals, the capacity of an antioxidant complex (AOC) – vitamins (lycopene, β-carotene, α-tocopherol), selenium – to reduce UV-induced damages. The AOC was administered orally, daily during 7 weeks. Before and after irradiations, before and after the intake of the product, six parameters were studied: skin color by chromametry, minimal erythemal dose and, on skin biopsies, sunburn cells (SBCs), p53 detected by immunohistochemistry, pigmentation index, and levels of lipoperoxides (thiobarbituric acid reaction). Results: After the oral intake of AOC, we observed an elevation of the actinic erythema threshold (+20%, P=0.01) and a general reduction of the UV-induced erythemas, a reduction of the UV-induced p53 expression (P<0.05) and of SBCs (P<0.01), and a parallel reduction of the lipoperoxide levels (P<0.01). The pigmentation was increased (P<0.01). Conclusion: After the oral intake of an antioxidant complex, many parameters of the epidermal defense against UV-induced damages are significantly improved. The oral intake of AOC could provide a safe, daylong and efficient complement to photo-protective measures provided by topical and physical agents and may contribute to reduce the DNA damages leading to skin aging and skin cancers.

Assessment of the skin photoprotective capacities of an organo-mineral broad-spectrum sunblock on two ex vivo skin models.

Abstract: UV irradiation can cause cutaneous damage that may be specific according to the wavelength of UV rays. For example, damage from UVB irradiation manifests itself in the form of sunburn cells and enhancement of the expression of p53, while damage from UVA exposure results in an increase in the expression of vimentin. These reactions to UV irradiation were used in this work to evaluate the photoprotective capacities of two sunblock preparations that were applied to the surface of the skin. One sunblock preparation is a UVB absorber containing zinc oxide (ZnO) and titanium oxide (TiO 2 ) exclusively. The other sunblock preparation is a new organo-mineral sunblock containing Tinosorb M, OCM, ZnO and TiO 2 . Evaluation of the photoprotective capacities of both preparations on hairless rat skin and on in vitro reconstructed human epidermis revealed that they were effective in preventing UVB-induced damage. In contrast, only the organo-mineral sunblock was effective in the prevention of UVA-specific damage such as dermal alterations characterized by the expression of vimentin. Furthermore, our data support the fact that hairless rat skin and in vitro reconstructed human epidermis are a reliable basis for the evaluation of the photoprotective capacities of various sunscreens against UVB and UVA damage.

Narrow‐band ultraviolet B treatment for vitiligo, pruritus, and inflammatory dermatoses

Abstract: Background: Narrow-band ultraviolet B (NB-UVB) therapy has been used successfully for the treatment of inflammatory and pigmentary skin disorders including atopic dermatitis, psoriasis, mycosis fungoides, polymorphous light eruption, and vitiligo. Methods: This is a retrospective review of the treatment outcomes of 117 consecutive patients with vitiligo, pruritus, and other inflammatory dermatoses, excluding those with psoriasis and CTCL, who were treated with NB-UVB between 1998 and 2001 at our institution. Results: Approximately 80% of all patients showed improvement in their condition. NB-UVB phototherapy was well tolerated, with no serious adverse effects. In patients with vitiligo, 6.4% had an abnormal thyroid-stimulating hormone level and 6.5% had anemia. Conclusion: NB-UVB may be considered as a viable therapeutic option in the treatment of vitiligo, pruritus, and other inflammatory dermatoses. Long-term adverse effects and cost–benefit analysis of NB-UVB therapy compared to other treatment modalities remain to be determined.

Seborrheic keratosis in the Korean males: causative role of sunlight

Abstract: Background/Purpose: Seborrheic keratoses (SKs) are common epidermal tumors in the white population over 40 years. The etiology of SKs is not well known; however, exposure to sunlight was suggested to play a role in the development of them. To our knowledge, no well-designed study has been undertaken in order to investigate the clinical characteristics of SKs in a brown-skinned Korean population. The aim of this study was to assess the prevalence and clinical features of SKs in the Korean males and to investigate the possible relationship of SKs with sun exposure and possible risk factors of developing SKs. Methods: A total of consecutive 303 male volunteers, aged 40–70 years, were recruited from general community and public health centres. Each volunteer was interviewed regarding demographic data, sunlight sensitivity, lifetime cumulative sun exposure and smoking history. Skin examination was performed except for scalp, buttocks and genitals. All SKs were recorded about the anatomical distribution, the size of each lesion measured with a caliber, color and morphology. Results: The mean overall prevalence of SKs in the Korean males, aged 40–70 years was 88.1%. A considerable increase in the prevalence of SKs was shown from 78.9% at 40 years to 93.9% at 50 years and 98.7% in those over 60 years. The mean number of lesions per person was 5.5 at 40 years, 9.2 at 50 years and 13.4 at 60 years. Seborrheic keratoses were considerably more frequent on exposed areas (0.47 ± 0.06/percentage of body surface area, BSA) than partly exposed areas (0.04 ± 0.01/percentage of BSA). The majority of lesions were concentrated on the face (0.98 ± 0.09/percentage of BSA) and on the dorsum of each hand (0.51 ± 0.08/percentage of BSA). The size of each lesion on exposed areas also became significantly larger by decade significantly (P < 0.01). The estimated area covered by SKs per percentage of BSA on exposed areas was 5.7-fold larger than that on partly exposed areas at 40 years, 11.2-fold larger at 50 years and 18.3-fold larger at 60 years. Aging by decade showed a 2.08-fold increased risk for SKs (n ≥ 6) (95% CI, 1.07–4.08) at 50 years and a 3.47-fold risk (95% CI, 1.67–7.20) at 60 years on exposed areas compared with the 40-year age group, for developing many SKs (n ≥ 6). Lifetime cumulative sunlight exposure of more than 6 h per day was associated with a 2.28-fold higher risk of SKs than a sun exposure of less than 3 h per day. A tendency for an odds ratio value reduction was found on increasing Fitzpatrick skin types I–III to VI, V; however, this was without statistical significance. Conclusions: Seborrheic keratoses are common in the Korean males, aged 40–70 years, and may be a major pigmentary problem. Both aging and cumulative sunlight exposure were found to be independent contributory factors.

UV exposure in cars

Abstract: Background: There is increasing knowledge about the hazards of solar and ultraviolet (UV) radiation to humans. Although people spend a significant time in cars, data on UV exposure during traveling are lacking. The aim of this study was to obtain basic information on personal UV exposure in cars. Methods: UV transmission of car glass samples, windscreen, side and back windows and sunroof, was determined. UV exposure of passengers was evaluated in seven German middle-class cars, fitted with three different types of car windows. UV doses were measured with open or closed windows/sunroof of Mercedes-Benz E 220 T, E 320, and S 500, and in an open convertible car (Mercedes-Benz CLK). Bacillus subtilis spore film dosimeters (Viospor) were attached to the front, vertex, cheeks, upper arms, forearms and thighs of ‘adult’ and ‘child’ dummies. Results: UV wavelengths longer than >335 nm were transmitted through car windows, and UV irradiation >380 nm was transmitted through compound glass windscreens. There was some variation in the spectral transmission of side windows according to the type of glass. On the arms, UV exposure was 3–4% of ambient radiation when the car windows were shut, and 25–31% of ambient radiation when the windows were open. In the open convertible car, the relative personal doses reached 62% of ambient radiation. Conclusions: The car glass types examined offer substantial protection against short-wave UV radiation. Professional drivers should keep car windows closed on sunny days to reduce occupational UV exposure. In individuals with polymorphic light eruption, produced by long-wave UVA, additional protection by plastic films, clothes or sunscreens appears necessary.

Dietary supplementation of (+)-catechin protects against UVB-induced skin damage by modulating antioxidant enzyme activities.

Abstract: Purpose: The aim of this study was to investigate the effects of dietary supplementation with (+)-catechin on cutaneous antioxidant enzymes and the skin damage caused by UVB irradiation. Methods: BALB/c mice were divided into three groups. Each group was fed a regular diet (RD) or a 2% catechin-supplemented diet for either 2 weeks (2CSD) or 4 weeks (4CSD) ad libitum prior to UVB irradiation. Skin was removed for the antioxidant enzyme assay, hematoxylin and eosin staining, and the TEM analysis before and at various time points after UVB (200 mJ/cm2) irradiation. Results: Before UVB irradiation, the superoxide dismutase (SOD) and catalase (CAT) activities of the 2CSD and the 4CSD groups were found to be lower than those of the RD group, whereas the glutathione peroxidase (GPx) activity of the 4CSD group was higher than those of the RD and the 2CSD groups (P<0.05). The SOD and CAT activities of the RD group decreased after UVB irradiation, while those of the 2CSD and the 4CSD groups increased immediately after irradiation and then decreased (P<0.05). Immediately after UVB irradiation, the GPx activities of the 4CSD and the 2CSD groups increased, but that of the RD group decreased. The GPx activity of all three groups showed a tendency to return to pre-UVB irradiation levels with time. Light microscopic findings of the RD group showed epidermal thinning and apoptotic cells at 24 h after UVB irradiation and mostly necrotic cells at 48 h, whereas only moderate thickening of the epidermis was observed in the 2CSD group at 48 h after irradiation. An electron microscopic examination produced similar findings. At 48 h after irradiation, nearly all epidermal cells seemed to be damaged in the RD group as compared to the 2CSD group. Conclusion: These results demonstrate that dietary supplementation with (+)-catechin could protect epidermal cells against UVB-induced damage by modulating antioxidant enzyme activities.

Photo(chemo) therapy for vitiligo

Abstract: Vitiligo has always been difficult to treat. Several modes of treatment are available, but the therapeutic effect varies greatly, and rarely does one achieve complete repigmentation. One of the most efficient treatment methods is photo(chemo) therapy. Already in ancient Egypt, vitiligo lesions were treated with extracts of the Ammi maius plant followed by exposure to the sun. This principle is at the basis of the photochemotherapy or PUVA therapy, whereby UVA irradiations are given 2 h after administration of 8-methoxypsoralen, a photosensitizer. Another efficient treatment form is UVB phototherapy, particularly narrow-band UVB. This not only gives good therapeutic results but also has the advantage of eliminating the need for a photosensitizer. All these treatments must be applied for many months to be efficient. They can also be combined with various surgical skin-grafting techniques. A newer approach is targeted UVB phototherapy, whereby xenon-chloride lasers or monochromatic excimer light is used.

Treatment of polymorphic light eruption

Abstract: Polymorphic light eruption (PLE) is a highly prevalent photosensitivity disorder, estimated to affect 11-21% people in temperate countries. Typically, PLE appears as a recurrent pruritic eruption comprising papules and/or vesicles and/or plaques, which occurs on photo-exposed skin sites following sun exposure, and which heals without scarring. Commoner in females, the aetiology is uncertain, although there is evidence of an immune basis. We perform a review of the prophylaxis and treatment of this condition. While sun protection, corticosteroids and desensitization phototherapy are the mainstays of management, a range of anti-inflammatory and immunomodulatory agents are reported.

Topical glycolic acid enhances photodamage by ultraviolet light

Abstract: Background: Alpha-hydroxy acids (AHAs) are widely used as ingredients in cosmetics. Several studies suggest that AHAs can increase the sensitivity of skin to ultraviolet (UV) light. Purpose: This study was performed in order to determine whether short-term dermal treatment with glycolic acid, a representative AHA, can enhance the damaging effects of UV light. The duration of the effect of AHAs on the sensitivity of skin to UV light was also examined. Methods: The backs of 29 Caucasian subjects were treated, once daily, 6 days per week with either 10% glycolic acid (pH 3.5) or placebo in a randomized double-blinded study. At the end of 4 weeks, sites within each treated area were exposed to 1.5 MED of UV light, determined on previously untreated skin. Specimens were obtained for enumeration of sunburn cells (SBCs) in the first group of subjects (n = 16), whereas cyclobutyl pyrimidine dimers (CPDs) in DNA were determined in the second group (n = 13). The minimal erythema dose (MED) in each site was also determined in the first group of subjects. Sunburn cells and MEDs were re-evaluated in the first group 1 week after discontinuing AHA applications. Results: Glycolic acid caused enhanced sensitivity to UV light measured as increased SBC induction and lowered MEDs. Cyclobutyl pyrimidine dimers were elevated but not to a statistically significant level. No differences in SBCs or MEDs were evident after a week of discontinued treatments. Conclusion: Short-term application of 10% glycolic acid sensitizes the skin to the damaging effects of UV light. This photosensitivity is reversed within a week of terminating treatments.

A study of differences in surface roughness between sun‐exposed and unexposed skin with age

Abstract: Background: To understand and separate the roles of age and solar ultraviolet exposure (sun damage) on the surface roughness of skin. Objectives: To determine the effects of age and site (sun exposed vs. unexposed) on skin roughness in normal healthy subjects. Subjects/Methods: Using a stylus profilometer and silicone skin surface replicas, we have measured skin surface roughness parameters on habitually exposed (back of hand) and habitually unexposed (upper buttock) skin sites from the same individual in a sample of 73 subjects from the normal population. We compared the two sites in order to determine any differences in roughness caused, we postulate, by the effect of solar ultraviolet exposure on the exposed site. Results: We found that the two sites are indistinguishable in roughness until after 30 years of age. For the over 30 years group, the difference between exposed and unexposed skin roughness correlated strongly with age. For all ages, skin roughness showed a positive correlation with age on the unexposed, but not the exposed, site. On the hand site subjects aged 40 years and older had significantly smoother skin than those aged less than 40 years, as measured by one roughness parameter. On the back, the older group had significantly rougher skin than the younger group measured by two roughness parameters. Conclusions: We propose that on the back of the hands, solar damage reverses or reduces the increase in roughness which would otherwise be caused by intrinsic ageing.

Description of the use of a risk estimation model to assess the increased risk of non-melanoma skin cancer among outdoor workers in Central Queensland, Australia.

Abstract: Background: The aim was to use the measured data on annual exposure to ultraviolet (UV) radiation in the risk estimation model to estimate the increase in risk of Non-Melanomic Skin Cancer (NMSC) among outdoor workers compared to indoor workers in Rockhampton (lat. 23°S), Central Queensland, Australia. Methods: Results on annual occupational exposure measured on two occupational groups namely Australia Post Mail Delivery Personnel (APMDP) and Physical Education Teachers (PE) using film badge dosimeters was used in the risk estimation model to determine the increase in risk of NMSC with years of outdoor occupational exposure compared to indoor workers. The sensitivity of the model was tested for variations in recreational and childhood exposure of both groups, as well as occupational exposure of indoor workers. Results: For APMDP the increase in risk for Basal cell carcinoma (BCC) varied from 1.1 to 3.6 for 5–20 years of exposure and for Squamous cell carcinoma (SCC) the risk varied from 1.2 to 5.5 for the same periods of exposure. For the PE teachers the risk for BCC varied from 1.1 to 1.8 and for SCC the range was 1.1–2.3 for similar exposure periods. Conclusion: The increased risk estimates did not show any significant changes for variations in occupational and recreational exposure. A maximum change of 20% was computed for 25% variation in childhood exposure, which was mainly for the APMDP with high occupational exposure levels and more than 10 years of occupational exposure. The increased risk estimates are useful to identify high risk groups at an early age and implement long-term protective measures against NMSC.

Immunomodulatory effects of low-intensity near-infrared laser irradiation on contact hypersensitivity reaction.

Abstract: Background/Purpose: Contact hypersensitivity (CHS) reaction is a useful model for studying the skin immune system and inflammatory reactions in the skin. In this study, an experimental model of CHS reaction was employed to assess immunomodulatory effects of near-infrared (near-IR) low-intensity laser (LIL) irradiation, which is used as adjuvant therapy in dermatology, physical medicine, rheumatology, etc., because of its declared anti-inflammatory, biostimulative and analgesic effects. Methods: The effects of near-IR LIL irradiation (λ=904 nm, irradiance 60 mW/cm2, fluence 3.6 J/cm2) on CHS reaction to 1-chloro-2,4-dinitrochlorobenzene (DNCB) in Albino Oxford rats were examined by irradiating experimental groups of animals before the induction phase of CHS reaction, while nonirradiated animals and animals that received vehicle instead of hapten served as controls. Ear-swelling assay, histopathological examination of H&E preparations of ear skin, computer-assisted image analysis of dermal infiltrate, ear skin organ culture with the determination of cutaneous production of tumour necrosis factor-α (by ELISA assay) and nitric oxide (by Griess' assay) were used for measuring the effects of LIL in the elicitation phase of CHS reaction. Cellularity, dendritic cell content, flow cytometry and proliferation assays (spontaneous and in the presence of IL-2 and concanavalin A) of the draining lymph node cells (DLNC) were performed for the assessment of LIL irradiation effects in the induction phase. Results: In the irradiated group of animals, ear swelling was significantly diminished compared to control animals (101±11.5% vs. 58±11.6%, P<0.01). This was accompanied by a highly significant decrease in the density of dermal infiltrate (22±0.81 vs. 14.2±1.75 cells per unit area, P<0.01) and a significant decrease in nitrite levels in the medium conditioned by organ-cultured ear skin (17.63±1.91 vs. 3.16±1.69 μM NaNO2; P<0.01), while TNF-α concentration was not changed. Cellularity and dendritic cell content in DLNC population, as well as the expression of TCR-α, CD4, CD8 and CD25, were not changed between irradiated and nonirradiated animals. Proliferation rates of DLNC cultured for 72 h were significantly lower in irradiated animals (17.3±4.1 vs. 13.9±0.9×103 c.p.m.; P<0.01). In cultures of DLNC with added rIL-2 or 0.5 μg/ml of concanavalin A, proliferation rates were also significantly decreased in irradiated animals (34.7±3.5 vs. 31.2±2.9×103 c.p.m. in IL-2-supplemented culture, P<0.01; 70.9±6.4 vs. 58.3±9.1×103 c.p.m. in concanavalin A-supplemented culture, P<0.01). However, this effect was overcome in the presence of the higher concentration of concanavalin A (2.5 μg/ml) (nonirradiated 38.7±3.1, irradiated 123.1±7.3×103 c.p.m., P<0.01). Conclusion: LIL irradiation showed a systemic immunomodulatory effect on CHS reaction to DNCB in rats. Decreased ear swelling observed in the elicitation phase was associated with diminished proliferative responses of the DLNC in the induction phase of CHS reaction. Further experimental work is needed to examine the possible mechanisms of these effects.

Non-invasive in vivo determination of UVA efficacy of sunscreens using diffuse reflectance spectroscopy.

Abstract: Background: Evaluation of sunscreen efficacy is most relevant when measured on the surface it is meant to protect, namely on human skin in vivo. Application of any material to the surface of the skin alters its optical properties. Diffuse reflectance spectroscopy (DRS) is a non-invasive technique to measure changes in the optical properties of the skin decoupled from its biological responses following sunscreen application. Methods: This study compared measurements of UVA efficacy of oxybenzone and avobenzone at different concentrations (0–5%) using DRS, human phototest and an in vitro technique. Twenty subjects were enrolled for each product measured by DRS and 10 different subjects were enrolled for each product measured by human phototest. Six areas 5 cm × 10 cm were outlined on each subject's back. DRS measurements were performed on four subsites within each area before and 20 min after sunscreen application. UVA efficacy for each concentration of product was calculated from the measured transmission spectrum of a given product convoluted with the spectrum of a Xenon light source adequately filtered to obtain the UVA spectrum from 320 to 400 nm and the erythema action spectrum. Phototesting was performed using the same light source and persistent pigment darkening as the biological endpoint. Measurements were made with sunscreen coverage of 2 mg/cm2. In vitro measurements were performed using an Optometrics instrument. Results: All three techniques showed a linear response between calculated UVA efficacy and product concentration. Conclusions: This study showed that DRS is a rapid and reproducible method to calculate UVA efficacy of sunscreen materials and that its results correlate closely with those obtained by human phototesting.

Assessment of the usefulness of skin phototype and skin color as the parameter of cutaneous narrow band UVB sensitivity in psoriasis patients

Abstract: Background: Many reports have been released to assess skin types, skin colors and cutaneous sensitivity to broad band UVB or UVA. Objective: This study was performed to investigate the usefulness of skin type and skin color as the parameter of narrow band UVB (NBUVB) sensitivity. Methods: The minimal erythema dose (MED) of 40 psoriasis patients was investigated by irradiating several doses ranging from 200 to 1500 mJ/cm2. Before phototesting, the skin color of buttock was measured with a tristimulus colorimeter. Results: The median and mode value of MED of NBUVB was 950 mJ/cm2. Skin type was well correlated with the MED and there was a significant relationship between the L* value and MED, but not for the a* and b* values. Conclusion: The MED value of NBUVB in our study is a basic data to set the phototherapy protocol. Our result showed that skin type and L* value might be useful for predicting the sensitivity to NBUVB irradiation.

Narrowband UVB therapy in the treatment of lichen planus.

Abstract: Background: Recently, UVB lamps with a peak emission around 311 nm have been used successfully for the treatment of many dermatologic diseases known to be treated with psoralen plus UVA (PUVA). Narrowband UVB (NBUVB) radiation causes less erythema and carcinogenicity with lower cumulative doses than PUVA, while the treatment response remains high. Lichen planus (LP) is a cell-mediated immune response of unknown origin. Methods: We present our results of NBUVB therapy administered to 10 LP patients. The sessions were administered three to four times weekly with an average cumulative dose of 17.7±1.6 J/cm2. Results: Five patients responded completely, and four were partially responsive at the end of the 30th session. Three of the partially responsive cases responded completely at the 31st, 36th and 51st sessions, respectively. Conclusion: Clinical improvements observed in our study as well as the potential advantages of NBUVB imply that it is an inevitable treatment alternative for resistant cases of LP.

Solar urticaria-idiopathic?

Abstract: Urticaria is an extremely common disease that appears in 15–20% of the general population at some time in their lives (1). Among them, however, solar urticaria is a relatively rare type of physical urticaria. As Magnus stated, the practicing clinician might expect to have the opportunity to see three or four patients in a professional lifetime (2). The present author has seen 60–70 patients with solar urticaria so far during the past 30 years. Careful and detailed examinations may reveal more cases than expected. The diagnosis of solar urticaria can be easily made from its characteristic features, although the causative factors cannot be often found for other types of urticaria. Patients themselves usually recognize sunlight as the provocative agent. Wheal reaction can be easily reproduced in most patients with physical urticaria including solar urticaria. In the present article, solar urticaria will be discussed, focusing mainly on the pathomechanism of the disease.

A questionnaire survey of attitudes to and usage of sunscreens in northwest England

Abstract: Background/Purpose: Sunscreens are employed with the aim of reducing the deleterious effects of ultraviolet radiation (UVR), but little is known about their use in the UK. Methods: This questionnaire survey assessed attitudes to and usage of sunscreens in northwest England in 2000. Subjects (186 females and 102 males) were recruited from the waiting rooms of four general practices, with a high response rate of 97%. Results: Females were more frequent users of sunscreens than males, but only 35% females and 8% males reported their regular use. Twenty-two per cent of the study population did not use sunscreens at all, whereas 66% of subjects bought a sunscreen product once a year or less. Thirty-four per cent subjects reported experiencing sunburn in the last 2 years. Interestingly, more (60%) sunburns were found to occur at home in the UK than on holidays abroad, and these frequently occurred during outdoor activities other than deliberate sunbathing. Conclusion: There remains much scope for sunscreen education in the British public.

Sun protection offered by fabrics: on the relation between effective doses based on different action spectra

Abstract: Background: Ultraviolet (UV) radiation threshold levels have been suggested by the International Commission on Non Ionising Radiation Protection (ICNIRP). The ICNIRP action spectrum differs from the action spectrum proposed by the International Commission on Illumination (CIE). Industrial hygienist employs the first approach while dermatologists and photobiologists commonly use the CIE spectrum. Objectives: By means of the ICNIRP and CIE action spectra we aimed to calculate the ultraviolet protection factor (UPF) for clothing as a function of the UV index, and to elucidate the relation between the two action spectra. Methods: Using a theoretically calculated solar spectrum that was determined by means of radiation transfer modelling the relation between the effective doses were assessed which were obtained by using the ICNIRP or the CIE action spectra. Employing the guidelines set out by the ICNIRP and the CIE the protection requirements for clothing were also calculated. Results: It was found that the UPF of a textile material should be at least 2.25 times the maximum UV index observed on a cloudless day to comply with the guidelines of the CIE, or should be at least 4.13 times the maximum UV index to comply with the guidelines of the ICNIRP. Conclusions: In Northern Europe a UPF 40 + should indeed comply with the exposure limits (EL) proposed by the CIE or ICNIRP. However, in Southern Europe, where UV index can, as in Australia, be as high as 11 the EL can in principle be exceeded for outdoor workers or individuals staying outside the whole day. Taken into consideration the exposure geometry a clearly lower UPF seem to be sufficient in a realistic exposure situation. Nevertheless we recommend a UPF 40 + that is sufficient in extreme exposure situations in every geographical location and also resistant against UPF-decreasing effects (‘worst case scenario’).

Uniformity of sunscreen product application: a problem in testing, a problem for consumers.

Abstract: Background/Aims: Testing of sunscreen products requires application of uniform films of product of defined thickness to test volunteers. In spite of the seeming importance of product application to defining sunscreen efficacy, there have been few studies determining how well uniformity is achieved. The purpose of this work was to evaluate the uniformity of sunscreen products of different sun protection factors (SPFs) and vehicles on a variety of substrates by in vitro testing techniques. The results of a variety of testing strategies are reported. Methods: Five commercial sunscreen products of labelled SPF 4–50 were tested using a variety of substrates: Transpore® Tape, Vitro-Skin™, and lambskin condom. Two experienced sunscreen testers applied the products. In vitro SPFs were determined using an Optometric 290 analyser or an Optronic Laboratories OL754 spectroradiometer configured for this application. Results: SPFs for several locations on each film applied to a substrate were determined and the mean SPF and RSD percentage of the mean calculated. For all substrates and testing techniques the average RSD percentage was 18.6, with a range of 10–40%. Conclusion: The expected uncertainty of SPF due to product application non-uniformity is 20% when applied under optimal test conditions. Clearly SPF tests reported by different laboratories must exhibit significant variability, because of product application non-uniformity.

Diurnal and seasonal variations of the UV cut-off wavelength and most erythemally effective wavelength of solar spectra.

Abstract: Background Biologically effective solar ultraviolet radiation is defined as the product of the intensity of the solar spectrum and the erythema action spectrum at each wavelength. In this way we may arrive at the weighted effectiveness of each wavelength of solar radiation to produce a sunburn reaction. There have been many measurements of the variation of the solar spectrum with the time of the day and the time of the year, but questions remain as to the variation of the quality of the spectrum and the contribution of the shortest wavelengths of solar terrestrial radiation. The purpose of the present study was to determine the variation of the biologically effective solar spectrum with the time of the day and the time of the year and to determine the variation of the shortest wavelength that contributes to the sunburn reaction with the time of the day and the time of the year. Methods Spectroradiometric measurements were made at ground level over the period of one year (1988–1989) and at different times of the day at latitude 29.5° north. The measured spectral irradiance was multiplied wavelength by wavelength by the erythema action spectra. Results We determined that the biologically effective solar spectrum remains essentially the same over the times of the day that sunburn may be experienced. The maximally effective wavelength of biologically effective solar radiation was determined to be 308 nm. The cut-off wavelength for biologically effective solar radiation (defined as the wavelength at which the biologically effective solar radiation is at 1% of its maximum) varied from 291 to 295 nm over the time of the year and from 292 to 296 nm over the day. Conclusion For all practical purposes the biologically effective spectrum of solar ultraviolet radiation may be considered to remain constant over the period when sunburn may occur and the minimal wavelength of sunlight that contributes to sunburn is in the range of 291–296 nm.

Direct effects on proliferation, antigen expression and melanin synthesis of cultured normal human melanocytes in response to UVB and UVA light

Abstract: Background/Purpose : Ultraviolet (UV) radiation induces a variety of responses in the skin, including tanning and inflammation, and may also act as a carcinogen. As epidermal melanocytes are seen as the major targets of UV light, the present study was conducted to evaluate the direct effects of UVA and UVB irradiation on melanocytes in vitro. Methods: Normal human epidermal melanocytes (NHM) were exposed on 3 consecutive days to UVA (0.072-7.2 J/cm 2 ) and UVB (7.2-48mJ/cm 2 ), respectively, and changes of morphology, cell number, melanin synthesis and antigen expression (APAAP technique) were determined 5 days after the first exposure. Results: UVA radiation caused only minimal effects on NHM by slightly inducing expression of the activation marker HMB-45 and decreasing expression of the proliferation marker Ki-67. No changes of morphology, cell number or melanin synthesis were detectable with any of the applied doses. On the other hand, UVB radiation significantly induced dendrite formation and decreased the number of NHM in a dose-dependent manner (74% of the controls at 7.2mJ/cm 2 , 64% at 14.4mJ/cm 2 and 28% at 36mJ/cm 2 ). Significant induction of the activation marker HMB-45 was found in parallel to decreased expression of the differentiation marker K.1.2.58. UVB doses ≥9.6mJ/cm 2 also resulted in significant downregulation of the proliferation marker Ki-67, confirming the data of the cell counts, and melanin content was increased in NHM (20% over the controls, P<0.01) after applying 7.2mJ/cm 2 UVB. Conclusion: Our results may suggest that the effect of UVB radiation in skin is due to direct activation of melanocytes, whereas skin tanning caused by UVA is mediated rather in an indirect way.

Thalidomide inhibits UVB-induced mouse keratinocyte apoptosis by both TNF-α-dependent and TNF-α-independent pathways

Abstract: Background: Thalidomide is an anti-inflammatory pharmacologic agent that has been utilized as a therapy for a number of dermatologic diseases. Its anti-inflammatory properties have been attributed to its ability to antagonize tumor necrosis factor-alfa (TNF-α) production by monocytes. However, its mechanism of action in the skin is not known. Purpose: To test our hypothesis that thalidomide may antagonize TNF-α production in the skin, we used a mouse model for acute ultraviolet-B (UVB) exposure, a known stimulus for inducing this cytokine. Results: A single bolus dose of thalidomide (either 100 or 400 mg/kg) given immediately before UVB exposure (40-120 mJ/cm2) inhibited, in a dose-dependent manner, sunburn cell formation (i.e. keratinocyte (KC) apoptosis as defined by histologic appearance and confirmed by terminal transferase mediated biotinylated dUTP nick end labelling staining) in mouse skin biopsy specimens. However, this agent did not affect the formation of cyclobutane pyrimidine dimers, a measure of UVB-induced DNA damage, which is an early event associated with apoptosis. RNase protection assays confirmed that high (400 mg/kg), but not low (100mg/kg), doses of thalidomide inhibited the UVB-induced increase in steady-state TNF-α mRNA. Additionally, our in vitro data using neonatal mouse KCs showed that thalidomide prevented UVB-induced cell death (JAM assay). The antiapoptotic effects of thalidomide can be reversed by the addition of exogenous recombinant mouse TNF-α and hence reconstituting UVB-induced programmed cell death. The inhibition of sunburn cell formation by low-dose thalidomide in the absence of TNF-α inhibition suggests that other, unidentified mechanisms of apoptosis inhibition are active. Conclusions: These data suggest that the anti-inflammatory effects of thalidomide can affect UVB injury, and may, in part, explain its action in photosensitivity diseases such as cutaneous lupus erythematosus.

The photopatch test procedure of the German, Austrian, and Swiss photopatch test group.

Abstract: In 1984 the German, Austrian, and Swiss photopatch test group was established to investigate photoallergic reactions as well as the epidemiology of photoallergy in central Europe. Therefore, the photopatch test procedure was defined and photopatch test data of 3998 patients were evaluated after two test periods from 1984 to 1990 and from 1991 to 1997. In summary, non-steroidal anti-inflammatory drugs, disinfectants, phenothiazines as well as sunscreens were found to be relevant photoallergens in central Europe. Based on the study results and guided by contemporaneously published clinical findings, the German, Austrian, and Swiss photopatch test group released in the year 2000 an optimized photopatch test tray, including a block of 19 photosensitizers, ranging from some historical to newly reported photosensitizers. This standard set is complemented by an optional photopatch test set, indicated only in special cases.

Sunbathing vs. indoor tanning: a realistic perspective.

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Photosensitive erythema multiforme and erythema multiforme-like polymorphous light eruption.

Abstract: Background: Photosensitive erythema multiforme (EM) is a rare disorder. It usually occurs only if a herpes virus infection or ingestion of drugs precedes exposure to sunlight in selected patients. Methods: We report a 37-year-old man who had recurrent EM eruptions following sun exposures over a period of 20 years. Lesions were prevalently located on exposed skin, but unexposed skin and mucosa of the oropharynx were also affected. The patient had poor tolerance to sunlight and denied having herpes simplex infection or using drugs. Results: Provocative phototest induced clinically and histologically similar lesions at low dose thresholds of UVA (10 J/cm2) and UVB (100 mJ/cm2). Conclusion: On the basis of clinical and histological findings and results of phototesting, a diagnosis of photosensitive EM was made. The EM-like variant of polymorphous light eruption is discussed in the differential diagnosis.