118例志愿者紫外线最小红斑量值测定

目的 测定118例志愿者长波紫外线(UVA)和中波紫外线(UVB)的最小红斑量(MED)正常值。方法 以SUV1000型日光紫外模拟仪为光源,测定118例健康志愿者和非炎症性皮肤病患者UVA-MED和UVB-MED正常值。结果 UVA-MED均值男性为55J/cm²(18-95J/cm²),女性40J/cm²(15-100J/cm²);UVB-MED均值男性31mJ/cm²(12-95mJ/cm²),女性29mJ/cm²(8-95mJ/cm²)。男性UVA-MED显著高于女性(P<0.05),UVB-MED两性间差异无统计学意义(P>0.05)。皮肤光反应类型为Ⅲ型的受试者UVA-MED和UVB-MED均显著低于Ⅳ型(两种类型皮肤UVA-MED:在男性、女性均P<0.05;UVB-MED:在男性P<0.05,女性P<0.01)。女性的年龄与MED值无关;30-49岁男性UVB-MED低于其他年龄组,UVA-MED与年龄无关。遮光部位测得的UVA-MED和UVB-MED与户外停留时间长短无关。结论 皮肤光反应类型是决定MED的重要因素。     

The Relationship of Sun Protection Factor to Minimal Erythema Dose,Japanese Skin Type,and Skin Color

The relationship of sun protection factor (SPF) to minimal erythema dose (MED), Japanese skin type, and skin color was investigated on the unexposed backs of 48 healthy subjects. SPF of a UVB-sunscreen was determined using sun lamps as a light source. A significant correlation was found between SPF and MED; subjects with lower MED showed higher SPF. The average SPF decreased with increasing skin type. There was no significant correlation between SPF and skin color (L*a*b* color system).     

Validation of a semiautomated method of minimal erythema dose testing for narrowband ultraviolet B phototherapy

BACKGROUND: The most widely used method for establishing the minimal erythema dose (MED) before narrowband ultraviolet (UV) B phototherapy is time-consuming, inconvenient and may yield inconsistent results. OBJECTIVES: To assess the equivalence of MED assessment using a filtered xenon arc lamp UV source, a semiautomated MED tester, and a UV-opaque template method of MED determination with a panel of TL-01 311-nm UVB fluorescent tubes. Secondly, to gauge the current usage of MED testing, and the method used, in a large sample of U.K. phototherapy units. Thirdly, to assess variation in UV output of the semiautomated skin tester immediately after switching on to identify optimum warm-up time. Finally, to assess reproducibility of MED testing by assessing within-patient variability and interobserver variability of MED test results. METHODS: Sixty-five patients about to undergo UVB phototherapy had their MED determined using three different methods. Within each patient we compared the values of MED determined by a semiautomated Durham MED tester, a panel of narrowband UVB lamps with a UV-opaque template constructed by a phototherapist, and a 310-nm filtered xenon arc lamp with a liquid light guide. MED test results were assessed by clinical evaluation using a 6500 K colour temperature examination lamp. The output of the semiautomated MED tester was measured by spectroradiometer over a period of 20 min in order to identify the time to steady output. Reproducibility of MED testing with the semiautomated MED tester was carried out in 25 normal volunteers. All MEDs were assessed by at least two independent observers. A postal questionnaire was sent to 78 U.K. phototherapy units to assess routine practice concerning MED testing prior to narrowband UVB phototherapy. RESULTS: The semiautomated MED tester showed consistency with the panel method (r = 0.92, panel MED = -0.57 + 1.14 x Durham MED). The semiautomated MED tester produced a slightly lower MED result than the panel MED. Reproducibility tests showed high interobserver agreement (kappa value = 0.79), and high consistency for successive day testing (kappa value = 0.79). Questionnaires were returned from 67 of 78 phototherapy units (85%) and revealed that 19 units (28%) were routinely using MED testing prior to UVB therapy. CONCLUSIONS: This study has shown the Durham MED tester to be a convenient, valid and reproducible method for determining patient MED values prior to narrowband UVB phototherapy when used under carefully controlled lighting, by experienced observers.     

广州地区102例正常人紫外线最小红斑量测定

目的:测定广州地区正常人紫外线最小红斑量(MED)的正常值范围,探讨其与性别、年龄、皮肤日光类型的关系。方法:以SUV1000型日光紫外模拟器作为照射光源,测定102名健康志愿者腹部正常皮肤的MED值(Ⅲ型、Ⅳ型皮肤)。结果:102名受试者MED均值:UVA为50.0 J/cm2,UVB为43.0 m J/cm2。不同皮肤类型间,Ⅲ型皮肤MED均值:UVA为38.5 J/cm2,UVB为36.1 m J/cm2;Ⅳ型皮肤MED均值:UVA为50.0 J/cm2,UVB为47.0 m J/cm2,Ⅳ皮肤MED均值均明显大于Ⅲ型皮肤(P值均<0.01)。不同性别间,男性MED均值:UVA为50.0 J/cm2,UVB为43.0 m J/cm2;女性:UVA为50.0 J/cm2,UVB为43.0 m J/cm2,不同性别间差异均无统计学意义(P值均>0.05)。不同性别的不同年龄阶段间UVA、UVB MED均值差异均无统计学意义(P值均>0.05);UVA-MED的正常值范围为≥30 J/cm2,UVBMED的正常值范围为≥29.1 m J/cm2。结论:紫外线MED的影响因素与皮肤日光反应类型有关,Ⅲ型皮肤UVA-MED、UVB-MED均明显低于Ⅳ型皮肤(P<0.01)。本组受试者MED与性别和年龄无直接关系。     

Photosensitivity of murine skin greatly depends on the genetic background: clinically relevant dose as a new measure to replace minimal erythema dose in mouse studies

Artificial UV irradiation of murine skin is a frequently used method for testing photosensitivity, study carcinogenesis and photoprotective effects of different compounds. However, doses of UV radiation and mouse strains used in experiments vary greatly. The genetic background of mice may influence the photosensitivity as melanin content, pigmentation and hair cycle parameters are dissimilar. Doses of UV are often expressed in relation to the minimal erythema dose (MED) that was not necessarily determined for the given strain. We set out to standardize the method of measuring photosensitivity in three commonly used mouse strains, C57BL/6N, Balb/c and SKH‐1. We found that MED may not be determined for some strains as erythema development in mice with diverse genotypes differs greatly. We measured the oedema response in vivo and ex vivo by using OCT. Given the strain‐specific variability of erythema, we introduced Clinically Relevant Dose (CRD) as a new term to replace MED in experiments, to describe the lowest dose that triggers a perceptible skin reaction in mice. Not only the CRD but the proportion of erythema and oedema were different in strains examined. C57BL/6N mice display skin reactions at the lowest UVB dose, while SKH‐1 hairless mice show changes, mostly oedema, after higher doses of UVB. The cellular composition and skin thickness were examined by histopathology. IL‐1beta and IL‐6 levels in skin correlated with the increasing doses of UVB. Despite the variations in the degree of erythema and oedema, no major differences in cytokine expressions were seen among various strains of mice.     

Dermatomyositis: comparative studies of cutaneous photosensitivity in lupus erythematosus and normal subjects

PURPOSE: Cutaneous features of dermatomyositis (DM) strongly suggest that ultraviolet (UV) radiation plays an important role in the pathogenesis of the disease. However, the incidence and the nature of photosensitivity in this disorder have not been established. The aim of this study was to investigate the UVB (290-320 nm) minimal erythema dose (MED) in DM patients in comparison with those in lupus erythematosus (LE) and healthy controls. METHODS: Non-irradiated back skin of 75 Caucasians with skin types II and III according to the Fitzpatrick classification were present in three different subject groups and tested for photomanifestation on non-irradiated suprascapular back skin with an ETG-1 Erythemtester. The first group included 19 DM patients, the second 30 patients with LE, and the third 26 healthy control volunteers. The MEDs were determined 24 h after irradiation adjusted according to skin type. RESULTS: Nine of the 19 DM patients (47.4%) demonstrated reduced MEDs to UVB radiation. Seven DM patients (36.8%) had a history of increased cutaneous photosensitivity and four of these (21.1%) reported diseased aggravation after sun exposure. Both the DM and LE patient groups showed reduced MED to UVB radiation (P<0.05) compared with the control group (19.2%). Increased erythemal sensitivity to UVB irradiation was found more frequently in patients with systemic LE and cutaneous discoid LE, than in those with subacute cutaneous LE. CONCLUSION: DM patients, similar to those with LE, showed a significantly reduced MED to UVB irradiation compared with healthy persons.     

UV transmission and UV protection factor (UPF) measured on split skin following exposure to UVB radiation — correlation with the minimal erythema dose (MED)

In this study the ultraviolet (UV) transmission of split skin exposed to UVB radiation and of non-exposed skin was compared in the 280-390 nm wavelength range and quantified. In addition, the correlation between the increase in the minimal erythema dose (MED) associated with a defined exposure to UVB and the ultraviolet protection factor (UPF) calculated from the transmission data was investigated. The study population consisted of 12 patients. Two pieces of split skin of the same thickness (0.3 mm) were taken from the right thigh of each patient. One specimen was removed from an area of non-exposed healthy skin and the other from an area which had been exposed to UVB radiation for a period of 12 days in which the initial dose of 1/3 MED was raised by 1/3 MED every 4 days. The split skin specimens were stretched over a special frame; subsequently, the UV transmission was determined with a spectrophotometer. The mean values obtained for UV transmission were all significantly below the initial data for non-exposed split skin. In the UV range of 280--390 nm, the transmission measured in the exposed specimens was 49.1% of the value measured in the non-exposed split skin (P<0.05). The corresponding values for the UVA range (315--390 nm) and the UVB range (280--315 nm) were 50.1% and 29.5%, respectively (P<0.05), based on the initial transmission data obtained from non-exposed skin. The clinical determination of MED after 12 days of exposure to UVB yielded mean values that were 3.2 times the initial values. Moreover, the mean UPFs calculated from the transmission data measured at the end of the 12-day exposure period were also about three times the initial values. The present study has thus established a significant correlation between the clinical MED values and the UPFs calculated from the transmission data measured following exposure to UVB.     

Long-term evaluation of erythema and pigmentation induced by ultraviolet radiations of different wavelengths

BACKGROUNDS/AIMS: Although multiple studies have been reported about the biological effects of ultraviolet (UV) radiations, the comparative and long-term reactions of human skin by several different UV-wavebands were not reported. The aim of this study was to investigate a time course of erythema and pigmentation induced by UVA 1, broad-band UVA (BBUVA), narrow-band UVB (NBUVB) and broad-band UVB (BBUVB). METHODS: Ten volunteers participated in this study for 6 months. Four skin areas, from the back of each subject, were irradiated with two minimal erythema dose (MED) of four different UV wavelengths corresponding to UVA 1, BBUVA, NBUVB and BBUVB. Skin color changes were evaluated by visual scoring and values were converted into the L*a*b color system. RESULTS: For both UVA 1 and BBUVA, erythema and pigmentation were most pronounced immediately and 1 h after exposure. Thereafter, erythema rapidly diminished but pigmentation persisted throughout the study. For both NBUVB and BBUVB, test areas reacted with erythema of maximum intensity at 1 and 2 days, respectively. A maximum tanning was reached at 3-6 days for NBUVB and 4-7 days for BBUVB, and the return toward the original color point was at 1 and 3 months, respectively. No significant difference was found in visual and colorimetric evaluation for the time course of skin color changes. CONCLUSION: Two MED of UVA produced far prolonged erythema and pigmentation than UVB. For UVA, UVA 1 and BBUVA showed similar intensity and time course of skin reaction. For UVB, erythema and pigmentation produced by NBUVB were milder in intensity and shorter in time course than those by BBUVB. These results would provide standard data on time courses and intensity of skin color changes by different UV wavelengths.     

The normal range in diagnostic phototesting

The minimal erythema doses (MED) to UVB and UVA radiation were measured in 254 normal subjects. Bivariate correlation analysis applied to the data showed a strong positive correlation between the UVB and UVA MEDs. By calculating the probability that a given combination of UVB and UVA MEDs is likely to occur in normal subjects, it was shown that, in some instances, both the UVB MED and UVA MED observed in a given subject may be within their respective normal ranges, but that the particular combination is more in keeping with abnormal photosensitivity.     

Reduction of minimal erythema dose by sweating

BACKGROUND/AIMS: Solar ultraviolet (UV) radiation is the most important environmental risk factor for melanoma and non-melanoma skin cancer. It is known that tap water and saltwater baths have a photosensitizing capacity in subsequent UV irradiation of the skin. The aim of the present study was to determine the influence of sweating from heat or from physical activity on the photosensitivity of the skin. METHODS: Minimal erythema dose to ultraviolet B (MED/UVB) was determined on the inner forearms of 22 healthy volunteers with a Saalmann Multi-tester. Sweating had been provoked by heat (sauna for 10 min) and, on another occasion, physical exercise (jogging for 15 min) followed by MED/UVB testing in a similar way. RESULTS: Compared to baseline MED/UVB there was a highly significant decrease in MED/UVB of up to 31.6% (median 15.8%, mean 15.9% +/- 10.0) after 10 min in the sauna and up to 40.9% (median 16.3%, mean 17.2% +/- 12.5) after 15 min jogging (P < 0.0001). CONCLUSION: Sweat influences the hydration of the horny layer of the skin, resulting in a decrease in reflection and dispersion of UV light. Moderate physical activities such as jogging and/or heat may facilitate erythema reaction. By sweating, outdoor workers and people practicing outdoor sports who are exposed to considerable amounts of solar UV radiation further increase their risk of sunburn.     

Lack of photoprotection against UVB-induced erythema by immediate pigmentation induced by 382 nm radiation

Immediate pigment darkening (IPD) was induced on the backs of 11 human volunteers of skin types III and IV by exposing the skin to UVA radiation (382 nm). The minimum erythema dose (MED) of UVB radiation was also determined by exposing sites to graduated doses of 304 nm radiation. The order of exposure of distinct anatomic areas was as follow: UVB followed by IPD induction; IPD induction followed by UVB; IPD induction followed 3 h later by UVB; and UVB only. Erythema responses induced by UVB were graded by inspection 24 h later and the MEDs in the 4 areas were compared. The induction of IPD before UVB exposure caused no significant change in the MED compared to sites receiving UVB only, or receiving UVA radiation after UVB, confirming that the IPD reaction does not protect against UVB-induced erythema. There was also no evidence of photorecovery, i.e., an increase in the MED of UVB resulting from exposure to longer wavelength, UV or visible radiation following UVB exposure.     

97例慢性光化性皮炎患者作用光谱分析

【摘要】 目的 测定慢性光化性皮炎(CAD)的紫外线作用光谱并进一步分析患者病程及日均户外曝光时间对作用光谱最小红斑量(MED)降低的影响。方法 以SUV1000型日光紫外线模拟器为光源,测定108例疑似CAD患者的长波紫外线(UVA)和中波紫外线(UVB)的MED。 结果 108例患者中,97例确诊为CAD。97例患者中,85.57% UVA－MED降低,范围1.02～23.97J/cm2;70.10% UVB－MED降低,范围1.94～19.23mJ/cm2;29.90% 单一UVA－MED下降;14.43% 单一UVB－MED下降。在不同病程组中,>5年组作用光谱的MED显著低于3～5年和<3年组的相应测定值（P<0.01）;3～5年组和<3年组作用光谱的MED之间则无显著性差异（P>0.05）。就日均户外曝光时间而言,>7小时／天组作用光谱的MED显著低于5～7小时／天和<5小时／天组的相应测定值（P<0.01）;而5～7小时／天和<5小时／天组作用光谱的MED之间无显著性差异(P>0.05)。结论 UVA作为CAD的单一作用光谱,不容忽视。且CAD患者病程的发展和户外曝光时间的延长会导致作用光谱MED进一步降低。     

The relationship of skin color, UVB-induced erythema, and melanogenesis

The relationship between skin color, delayed erythema, and delayed tanning (DT) elicited by a single exposure of UVB was investigated. Both constitutive and facultative pigmentation were determined by skin reflectance using a melanometer. Skin reflectance using visible light was well correlated to the minimal immediate pigment darkening dose elicited by UVA irradiation, which may relate to epidermal melanin content, a determinant of skin color. Minimal erythemal dose (MED) was well correlated to skin color, but there was less correlation between minimal melanogenic dose and skin color or the MED, since melanogenesis is controlled by genetic factors. DT also correlated to the dose of UVB in terms of MED. A coefficient of the regression line of DT may suggest the tanning capacity of skin. The possibility of detecting mild photosensitivity in individuals from a regression line of the MED on skin color is suggested.     

中波高能紫外线最小红斑量值测定

目的探讨中波高能紫外线最小红斑量值(MED)范围及其与年龄、性别、皮肤日光反应类型的关系。方法以Dualight targeted Phototherapy System UV120-2的UVB作为照射光源,测定73名健康志愿者和35例白癜风患者腹部正常皮肤的MED值范围。结果108名受试者MED值为(189.17±56.156)mJ/cm2,范围为90～330mJ/cm2;Ⅲ型皮肤为(155.88±34.996)mJ/cm2(90～210mJ/cm2),Ⅳ型皮肤为(218.95±54.957)mJ/cm2(120～330mJ/cm2),Ⅲ型显著低于Ⅳ型(P<0.01)。男性受试者中,Ⅲ型为(154.29±39.443)mJ/cm2(90～210mJ/cm2),Ⅳ型为(224.4±54.854)mJ/cm2(150～330mJ/cm2),男性Ⅲ型显著低于Ⅳ型(P<0.01)。女性受试者中,Ⅲ型为(157±32.179)mJ/cm2(90～210mJ/cm2),Ⅳ型为(214.69±55.532)mJ/cm2(120～330mJ/cm2),女性Ⅲ型也显著低于Ⅳ型(P<0.01)。两性别组间和各年龄组间比较无统计学差异(P>0.05)。结论中波高能紫外线的MED值与性别和年龄无直接关系,皮肤日光反应类型是影响其重要因素。     

A long-term evaluation of erythema and pigmentation induced by ultraviolet radiations of different wavelengths

BACKGROUND/AIMS: The long-term reactions of human skin by different ultraviolet (UV)-wavebands were not reported. This study was to investigate a time course of erythema and pigmentation induced by UVA-1, broadband UVA (BBUVA), narrowband UVB (NBUVB) and broadband UVB (BBUVB). METHODS: Ten volunteers participated in this study for 6 months. Four skin areas, from the back of each subject, were irradiated with two minimal erythema dose (MED) of four different UV wavelengths corresponding to UVA-1, BBUVA, NBUVB and BBUVB. RESULTS: For both UVA-1 and BBUVA, erythema and pigmentation were most pronounced immediately and 1 h after exposure. Erythema rapidly diminished but pigmentation persisted throughout the study. For both NBUVB and BBUVB, test areas reacted with erythema of maximum intensity at 1 and 2 days, respectively. A maximum tanning was reached at 3-6 days for NBUVB and 4-7 days for BBUVB, and the return toward the original point was at 1 and 3 months, respectively. CONCLUSION: Two MED of UVA produced far prolonged erythema and pigmentation than UVB. For UVA, UVA-1 and BBUVA showed similar intensity and time course of skin reaction. For UVB, erythema and pigmentation produced by NBUVB were milder in intensity and shorter in a time course than those by BBUVB.     

Azathioprine treatment photosensitizes human skin to ultraviolet A radiation

Background  Azathioprine is used to treat a variety of conditions and to prevent graft rejection in organ transplant recipients (OTRs).
Objectives  To investigate clinically our previous finding that azathioprine metabolites interact with ultraviolet (UV) A radiation to form promutagenic oxidative DNA damage and to determine whether this may be causal or contributory to the development of excess skin cancers post-transplantation.
Methods  The clinical corollary of these data were investigated. Five patients were recruited and the minimal erythema dose (MED) for UVB, UVA and solar-simulated radiation (SSR) was determined for each person before, and at least 12 weeks after, starting azathioprine therapy.
Results  In all five patients azathioprine treatment was associated with an increased UVA and SSR sensitivity of the skin and a significant reduction in MEDs for UVA and SSR. We found no change in UVB-induced erythema or MED. In addition, we found that DNA from the skin of patients on azathioprine contains 6-thioguanine (6-TG).
Conclusions  Our findings confirm the presence of DNA 6-TG in the skin of those taking therapeutic doses of azathioprine and provide support for the hypothesis that DNA damage occurs when DNA 6-TG interacts with UVA, resulting in abnormal cutaneous photosensitivity.     

Low-dose ultraviolet-B irradiation depletes human epidermal Langerhans cells

We have examined the effects of low-dose monochromatic UVB irradiation (295±5 nm), biologically equivalent to that generally incident on the skin during a 12-session sun-bed course, on the expression of the CDla epidermal Langerhans cell surface marker in human skin in vivo. In five subjects, 1.5 minimal erythema doses (MEDs) at 295 nm depleted its expression by 50%. In five further subjects, a single 1.5 MED dose, 1.5 MEDs in 10 equal fractions on alternate days, and a single 1.5 MED dose at one-tenth the previously used irradiance, delivered to separate sites, also led to variable but significant depletion of CD la expression of around-30–50%. Thus, low-dose UVB irradiation, whether received rapidly or slowly, appears significantly and approximately equally to deplete human epidermal Langerhans cell numbers as measured by CDla expression.     

Sun protection factor measurement of sunscreens is dependent on minimal erythema dose

This study investigates the influence of skin colour and minimal erythema dose (MED) on the in vivo determination of sunscreen sun protection factors (SPFs). The MEDs of groups of 10-20 subjects were measured on the lower back with a 1000-W solar-simulated xenon arc lamp. Five sunscreens, with commercially measured SPFs ranging from 4 to 30 + were then tested on the different groups, and their SPFs were correlated with volunteers' MEDs. We found that the sunscreens had higher SPF values when tested on subjects with lower MEDs and paler skin. The SPF values obtained with our ultraviolet (UV) source were lower than the SPF values reported with commercially used solar simulators. We conclude that while SPF tests with artificial UV sources and pale-skinned volunteers can and should be used to rank the efficacy of various sunscreens in preventing sunburn, they should not be interpreted as measures of a sunscreen's absolute level of sun protection. Factors such as the differences in skin colour and MED between subjects used for SPF testing and the general population, the spectral differences between sunlight and artificial UV, as well as the tendency of the public to apply only small amounts of sunscreen and to re-apply it infrequently, mean that laboratory and sunlight SPFs may be markedly different.     

330例慢性光化性皮炎患者紫外线最小红斑量测定

目的:分析慢性光化性皮炎(CAD)患者与长波紫外线(UVA)、中波紫外线(UVB)的关系,以及最小红斑量(MED)的影响因素.方法:以SUV1000型日光紫外线模拟器作为照射光源,比较330例CAD患者不同性别、年龄、病程及不同季节受试者UVA-MED值及UVB-MED值.结果:男性患者UVB-MED值明显低于女性ME...     

Feasibility and accuracy of a newly developed hand-held device with a flat-type fluorescent lamp for measuring the minimal erythema dose for narrow-band UVB therapy

Background: Narrow-band ultraviolet B (NB-UVB) for the treatment of refractory skin diseases, such as psoriasis and atopic dermatitis, requires an adequate irradiation protocol based on the minimal erythema dose (MED) to establish an optimal dosage schedule. Although MED can be measured using a systemic-type irradiation unit, there are difficulties associated with this device. There is no standardized device available to determine the MED for NB-UVB. Here, we compared a conventional device with a newly developed device for measuring MED.
Method: MED was measured in 16 psoriasis patients using both a conventional measuring device and the newly developed device, which comprised a hand-held NB-UVB (311–313 nm) flat-type fluorescent lamp with neutral density filters having different transmittances ranging from 10% to 90%. This device was designed to be stably maintained on the skin surface and to provide a highly accurate measurement with only one UV irradiation exposure while also preventing UV radiation from leaking to nonirradiated areas.
Results: The MED values obtained from each patient were the same using both devices.
Conclusion: One-time irradiation using the new hand-held device with the NB-UVB flat-type fluorescent lamp is feasible and accurate for determining the MED to use in calculating the UV irradiation treatment dose.