Study of sunscreens UV factor

Posters - Photobiology and phototherapy and UVA are photoproducts and strand breaks, respectively. Cells possess specific enzymatic systems to repair the DNA in response to UV exposure. Human keratinocytes were UVA- and UVB-irradiated in presence or not of the mineral sunscreen. We have followed both the localisation and the expression of HSP72 and ~53 by using immunolabelling technique and the damages accumulated in cellular genome by the comet assay. We have finally used an in vitro biochemical assay, 3D test, to follow the repair of UV-induced damages. In all models, the mineral sunscreen presents a significant nuclear protective effect against UV radiations. Besides, the results obtained from comet assay and from HSP72 immunolabelling are correlated and suggest the potential HSP72 role toward nuclear components. In conclusion, this sunscreen decreases the cutaneous photocarcinogenesis risk by limiting the nuclear alterations. I P406 Determination of the ultraviolet protection factor of fabrics in vitro and in vivo K. Kaspar, P. Altmeyer, K. Hoffmann. Department of Dertnatology, Ruhr University in Bochum, Germany The objective of our study was to compare the in vitro and in vivo determination of the ultraviolet protection factor (UPF) of fabrics. Four different viscose fabrics were investigated. ‘nvo of these fabrics had undergone a special treatment to confer UV protection. During the in vitro testing, the UV transmission of the fabric samples was measured in the 280-390 nm wave length range with a Cary 3 Bio (VARIAN) spectrophotometer. The UPF of the fabrics was then calculated from the data obtained. The in vivo measurements were made on the backs of 10 subjects with healthy skin; these measurements served as a check of the UPF values measured in vitro. A sun simulator served as the radiation source. The two fabrics which had received no special treatment yielded UPFs of I4 to 16, whereas UPFs between 33 and 35 were measured in the specially treated fabrics. During the in vivo measurement series, it was noted that the fabrics with low UPFs did not produce the UPF values obtained during the preceding in vitro measurements. In the specially treated viscose fabrics, on the other hand, the UPF values measured in vivo were at least as high as, and sometimes higher than, the in vitro values. This study has shown that - for fabrics with low UPF values at least - in vitro determination of UPF values is not sufficient. ElP407 Study of sunscreens UV factor M. JirfiskovB’, B. Stfidnf!?. ‘2’ld Dept. of Dermarology, I”’ Faculty of Medicine, Charles University; ‘Institute ORE AV CR, Prague, Czech Republic Measurement of dermatological sunscreens in the spectral wavelength range 254-880 nm was made using the set-up comprising optical source, spectrophotometer, optical analyser, photodetector and optical filters. wo optical sources were used: Xe-arc lamp with constant continuous optical output of 100 W in whole measuring wavelength range and Hg-arc lamp with output of 75 W at the discrete optical wavelengths 254, 302, 369. 575, 700 and 880 nm. The Xe lamp is more suitable for measurements in the visible wavelength range and Hg lamp in the short UV range. The samples with different cream thickness

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were put between two quarts glasses with good transparence in the UV range. The cream thickness varied around 5 p. All measurements were transformed to the sample effective thickness. Evaluation measurements of data were performed according to the modified Lambert law. Supported by grants UK 248195.

Photobiology and phototherapy course of photosensitivity in bath I P408 Time PUVA therapy with 8-methoxypsoralen D. Schreiber’, P. Altmeyer’, University of University of Dermatology,

C. Gruss’, S. Behrens3, T. Reuther’, M. Kersche?. ‘Department of Dermarology, Bochum, Bochum; ‘Department of Dermarology, Regensburg, Regensburg; 3Department of University of Vim, Vlm, Germany

Photochemotherapy with PsoraIens applied by using bath water delivery combined with long wave ultraviolet A light (bath PUVA) has proven to be an effective therapeutic modality for a variety of dermatoses. In spite of the increased usage, the kinetics of I-Methoxypsoralen (8-MOP) during treatment are not completely clarified. Therefore, we herein investigated the phototoxic response of the skin and the persistence of phototoxicity after bath PUVA photochemotherapy using UVA doses (up to 40 J/cm*) and time ranges (up to 4 hours) of practical relevance. tielve volunteers were exposed to whole body bath PUVA treatment. After the Psoralen bath untanned skin from the buttocks was exposed to UVA irradiation in time intervals from 10 to 240 minutes using UVA doses ranging from 0.5 to 40 J/cm’. The minimal phototoxic doses (MPD) were determined 72 hours after bath PUVA treatment. Irradiation 10 minutes after the Psoralen bath lead to the lowest assessed MPD of I .42 J/cm’ (mean, SD f 0.29). From then, the MPD increased significantly and sharply every hour. At three hours after bath treatment, UVA doses of 24-40 J/cm* were necessary to produce a phototoxic response (equivalent to sunlight exposure of at least one hour depending on the location, season and environment). At four hours after the psoralen bath UVA doses up to 40 J/cm? failed to induce any phototoxic erythema (MPD). For practical use, this means that no exceeded restrictive behaviour and costly precautions are necessary after bath PUVA treatment. The patients can go on with there usual lives as early as four hours after treatment. The knowledge of the high intensity and short-lived persistence of photosensitizationincreases the safety as well as effectiveness of this treatment modality. I P409 Induction of interstitial collagenase by

UVA-1 phototherapy in fibroblastic cells of morphea

C. Gruss’, J.A. Reed’, S. Behrens3, N.S. McNutt*, M. Landthaler’, W. Stolz’, M. Kersche?. ‘Department of Dertnatology, University of Regensbutg; 3Departmenr of Dermatology, University of Vlm, Germany: ‘Departments of Pathology and Dermatology, New York Hospital, Cornell University Medical Center; New York, USA Ultraviolet

light A-l (UVA-1) phototherapy has shown to be