Home  About us  Contact
 

Erythemal Dose (erythemal + dose)

Distribution by Scientific Domains
Medical Sciences50%
Life Sciences50%

Kinds of Erythemal Dose

  • minimal erythemal dose
    		•

    Selected Abstracts

    Effect of systemic hormonal cyclicity on skin

    INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2006
    N. Muizzuddin
    Fluctuations in estrogen and progesterone during the menstrual cycle can cause changes in body systems other than the reproductive system. We conducted several studies to determine a possible correlation between phases of the menstrual cycle and specific skin properties. Healthy Caucasian women (ages 21,48), who had a typical 26,29 day menstrual cycle, participated in the studies. Measurements of skin barrier strength, dryness, response to lactic acid stinging, skin surface lipids, and microflora were obtained every week for 2 to 3 months. Ultraviolet B (UV-B) susceptibility in terms of minimal erythemal dose was also studied. The skin barrier was the weakest between days 22 and 26 of the cycle. Elevated neuronal response (lactic acid sting) was not observed to vary much with the cycle. Skin was driest between day 1 and day 6, while skin surface lipid secretion appeared to be highest on days 16,20 of the hormonal cycle. The highest microbial count was around days 16,22, and there was a high UV-B susceptibility between days 20 and 28 of the menstrual cycle. [source]

    Adaptation of the Human Skin by Chronic Solar-simulating UV Irradiation Prevents Ultraviolet-B Irradiation-induced Rise in Serum C-Reactive Protein Levels,

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2005
    Jarmo K. Laihia
    ABSTRACT Exposure of the skin to UV radiation induces local inflammation. We hypothesized that inflammation induced by erythemal UV-B irradiation could elevate levels of serum C-reactive protein (CRP) and that suberythemal repeating doses of solar-simulating UV radiation (SSR) would produce photoadaptation to such inflammation. Separation-free high-sensitivity assays of CRP show an increase by 42% (P= 0.046) in CRP concentrations in healthy human subjects 24 h after a 3 minimal erythemal dose (MED) dose of UV-B delivered onto a 100 cm2 skin area. Preceding daily suberythemal doses of whole-body SSR for 10 or 30 consecutive days completely prevented the CRP increase. UV-B-induced skin erythema was partially attenuated by 30 preceding days of SSR only (P= 0.00066). After 10 daily SSR doses, the mean baseline CRP concentrations (0.24 ± 0.21 mg/L) declined by 35% (P= 0.018). Using high-sensitivity analysis of serum CRP as the endpoint marker for cutaneous inflammation, we show that acute exposure of even a relatively small skin area to erythemal UV-B induces skin inflammation detectable also at the systemic level and that photoadaptation by preceding repeating suberythemal doses of SSR reduces signs of inflammation. Our data complement the view given by previous studies in that local photoadaptation also has systemic manifestations. [source]

    UV Exposure of Elementary School Children in Five Japanese Cities,

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005
    Masaji Ono
    ABSTRACT A 1 week UV-exposure measurement and outdoor-activity pattern survey was conducted for elementary school children for four seasons at five sites in Japan, i.e. Sapporo (43°05,N, altitude 40 m), Tsukuba (36°05,N, 20 m), Tokyo (35°40,N, 45 m), Miyazaki (31°60,N, 40 m) and Naha (26°10,N, 5 m), and UV exposure was measured directly and estimated using outdoor-activity records. The study site with largest UV exposure was Miyazaki, a southern rural area. Comparing the results for boys and girls, UV exposure was larger in boys. UV exposure was large in spring and summer and small in winter. The total amount of UV exposure in spring and summer contributed 57.7,73.4% of total exposure for the year. As a whole, 8.1% and 1.8% of the schoolchildren were exposed to more than 1 minimum erythemal dose (MED) and 2 MED of solar UV in a day, respectively. The estimated yearly UV exposure ranged from 49 207 J/m2 in Miyazaki to 31 520 J/m2 in Tsukuba. The actual UV exposure correlated to potential UV exposure, estimated using outdoor-activity records and ambient UV irradiance, but the ratio differed by season and site. The yearly average of percent UV exposure to ambient UV on a horizontal plane ranged from 9.9% in Tokyo to 4.0% in Naha. In the questionnaire survey on outdoor-activity pattern, a short question "How long did you spend time outdoors between 0900 and 1500 h?" gives the best estimates of UV exposure. [source]

    The influence of the amount of sunscreen applied and its sun protection factor (SPF): evaluation of two sunscreens including the same ingredients at different concentrations

    PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2009
    Sergio Schalka
    Background: To estimate labeled sun protection factor (SPF) for sunscreen, the amount of product applied on volunteers, according to food and drug administration (FDA) and International protocols, is 2 mg/cm2. However, different studies have shown that consumers actually apply much less product when exposed to the sun. Previous studies have reported contradictory findings in an attempt to correlate the amount applied in relation to SPF. The objective of the present study was to estimate the influence of the quantity of sunscreen applied in the determination of SPF, according to the FDA methodology. Subjects and methods: Forty volunteers were included in two groups (SPF 15 and 30). The selected sunscreen was then applied in four different quantities (2, 1.5, 1.0 and 0.5 mg/cm2). All areas were irradiated with a solar simulator. After 24 h, the minimal erythemal dose (MED) and SPF were determined. Results: In both groups, we observed that the SPF decreased when the amount of sunscreen applied was decreased. The differences between the 2 mg/cm2 area and the others were significant in both groups (P<0.001). The correlation between specified SPF and applied amount grew exponentially. Conclusion: The protection provided by sunscreen is related to the amount of product applied. It is essential to educate consumers to apply larger amounts of sunscreen for adequate photoprotection. [source]

    Comparing Quantitative Measures of Erythema, Pigmentation and Skin Response using Reflectometry

    PIGMENT CELL & MELANOMA RESEARCH, Issue 5 2002
    Jennifer K. Wagner
    We measured a number of pigmentation and skin response phenotypes in a sample of volunteers (n=397) living in State College, PA. The majority of this sample was composed of four groups based on stated ancestry: African-American, European-American, Hispanic and East Asian. Several measures of melanin concentration (L*, melanin index and adjusted melanin index) were estimated by diffuse reflectance spectroscopy and compared. The efficacy of these measures for assessing constitutive pigmentation and melanogenic dose,response was evaluated. Similarly, several measures of erythema (a*, erythema index and adjusted erythema index) were compared and evaluated in their efficacy in measuring erythema and erythemal dose,response. We show a high correspondence among all of the measures for the assessment of constitutive pigmentation and baseline erythema. However, our results demonstrate that evaluating melanogenic dose,response is highly dependent on the summary statistic used: while L* is a valid measure of constitutive pigmentation it is not an effective measure of melanogenic dose,response. Our results also confirm the use of a*, as it is shown to be highly correlated with the adjusted erythema index, a more advanced measure of erythema based on the apparent absorbance. Diffuse reflectance spectroscopy can be used to quantify the constitutive pigmentation, melanogenic dose,response at 7 d and erythemal dose,response at both 24 h and 7 d postexposure. [source]

    Clinical evidence of benefits of a dietary supplement containing probiotic and carotenoids on ultraviolet-induced skin damage

    BRITISH JOURNAL OF DERMATOLOGY, Issue 3 2010
    D. Bouilly-Gauthier
    Summary Background,Lactobacillus johnsonii (La1) has been reported to protect skin immune system homeostasis following ultraviolet (UV) exposure. Objectives, To assess the effects of a dietary supplement (DS) combining La1 and nutritional doses of carotenoids on early UV-induced skin damage. Methods, Three clinical trials (CT1, CT2, CT3) were performed using different UV sources: nonextreme UV with a high UVA irradiance (UV-DL, CT1), extreme simulated solar radiation (UV-SSR, CT2) and natural sunlight (CT3). All three clinical trials were carried out in healthy women over 18 years of age with skin type II,IV. In CT1, early markers of UV-induced skin damage were assessed using histology and immunohistochemistry. In CT2, the minimal erythemal dose (MED) was determined by clinical evaluation and by chromametry. Chromametry was also used to evaluate skin colour. Dermatologists' and subjects' assessments were compiled in CT3. Results, A 10-week DS intake prevented the UV-DL-induced decrease in Langerhans cell density and the increase in factor XIIIa+ type I dermal dendrocytes while it reduced dermal inflammatory cells. Clinical and instrumental MED rose by 20% and 19%, respectively, and skin colour was intensified, as shown by the increase in the ,E* parameter. The efficacy of DS was confirmed by dermatologists and subjects under real conditions of use. Conclusions, Nutritional supplementation combining a specific probiotic (La1) and nutritional doses of carotenoids reduced early UV-induced skin damage caused by simulated or natural sun exposure in a large panel of subjects (n = 139). This latter result might suggest that DS intake could have a beneficial influence on the long-term effects of UV exposure and more specifically on skin photoageing. [source]

    UV Index Experimental Values During the Years 2000 and 2001 from the Spanish Broadband UV-B Radiometric Network,

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2002
    José A. Martínez-Lozano
    ABSTRACT An analysis is made of experimental ultraviolet erythemal solar radiation data measured during the years 2000 and 2001 by the Spanish UV-B radiation evaluation and prediction network. This network consists of 16 Robertson,Berger type pyranometers for evaluating solar erythemal radiation and five Brewer spectroradiometers for evaluating the stratospheric ozone. On the basis of these data the Ultraviolet Index (UVI) was evaluated for the measuring stations that are located either in coastal regions or in the more densely populated regions inland on the Iberian Peninsula. It has been checked that in most cases the maximum irradiance values corresponded to solar noon, although there were exceptions that could be explained by cloudiness. The maximum experimental values of the UVI were around 9 during the summer, though frequently passing this value at the inland measurement stations. The annual accumulated dose of irradiation on a horizontal plane has also been studied, as well as the evolution through the year in units of energy, standard erythemal doses and minimum erythemal doses, according to different phototypes. [source]

    Measured occupational solar UVR exposures of lifeguards in pool settings

    AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 8 2009
    Peter Gies PhD
    Abstract Background The aim of this study was to measure ultraviolet radiation (UVR) exposures of lifeguards in pool settings and evaluate their personal UVR protective practices. Methods Lifeguards (n,=,168) wore UVR sensitive polysulfone (PS) film badges in wrist bracelets on 2 days and completed a survey and diary covering sun protection use. Analyses were used to describe sun exposure and sun protection practices, to compare UVR exposure across locations, and to compare findings with recommended threshold limits for occupational exposure. Results The measured UVR exposures varied with location, ranging from high median UVR exposures of 6.2 standard erythemal doses (SEDs) to the lowest median of 1.7 SEDs. More than 74% of the lifeguards' PS badges showed UVR above recommended threshold limits for occupational exposure. Thirty-nine percent received more than four times the limit and 65% of cases were sufficient to induce sunburn. The most common protective behaviors were wearing sunglasses and using sunscreen, but sun protection was often inadequate. Conclusions At-risk individuals were exposed to high levels of UVR in excess of occupational limits and though appropriate types of sun protection were used, it was not used consistently and more than 50% of lifeguards reported being sunburnt at least twice during the previous year. Am. J. Ind. Med. 52:645,653, 2009. © 2009 Wiley-Liss, Inc. [source]