Latreille Julie, Gardinier Sophie, Ambroisine Laurence, Mauger Emmanuelle, Tenenhaus Michel, Guéhenneux Sabine, Morizot Frédérique, Tschachler Erwin, Guinot Christiane
CE.R.I.E.S, Neuilly sur Seine, France.
Skin Res Technol. 2007 Aug;13(3):236-41. doi: 10.1111/j.1600-0846.2007.00212.x.
BACKGROUND/PURPOSE: This research aims at assessing the influence of baseline skin colour on the ability of reflectance spectrophotometry to detect cutaneous erythema induced by a low concentration of methyl nicotinate (2.5 mM) (first objective), and to detect tanning induced by ultraviolet rays (UVA+UVB) at infra-erythemal doses (second objective).
Two independent studies were conducted to reach their respective objectives, on 27 women for the first study and on 12 women for the second study. Skin colour measurements were expressed in two different ways: percentages of reflected light at increasing wavelengths lambda (400 nm<lambda<700 nm, at 10 nm intervals), and chromametric coordinates of the CIELab 1976 system and individual typological angle (ITA degrees). Partial least squares discriminant analysis was performed to identify percentages of reflected light that allow the discrimination of the observations obtained after methyl nicotinate application from those obtained after water application (control). The same method was used for the discrimination of the measurements obtained after UV irradiation from those obtained before UV irradiation (control).
The cutaneous erythema induced by a low concentration of methyl nicotinate was detected only in subjects with fair to very fair skin defined by ITA> or =40 degrees. The assumption is that in the darkest skins, the emitted light is mainly absorbed by the melanin in the epidermis. Otherwise, after UV irradiation, the tanning was detectable only for individuals with fair to dark skin defined by ITA <50 degrees. This can be explained by the fact that UV stimulation of the fairest skin subjects, known to be melano-compromised individuals, can only produce a weak tanning that our study did not succeed in detecting.
背景/目的：本研究旨在评估基线肤色对反射分光光度法检测低浓度烟酸甲酯（2.5 mM）引起的皮肤红斑能力的影响（首要目标），以及检测亚红斑剂量紫外线（UVA + UVB）引起的晒黑情况（次要目标）。
为实现各自目标进行了两项独立研究，第一项研究有27名女性参与，第二项研究有12名女性参与。肤色测量以两种不同方式表示：在波长递增时（400 nm < λ < 700 nm，间隔10 nm）的反射光百分比，以及CIELab 1976系统的色度坐标和个体类型学角度（ITA度）。进行偏最小二乘判别分析以确定能够区分涂抹烟酸甲酯后与涂抹水后（对照）所获得观察结果的反射光百分比。使用相同方法区分紫外线照射后与紫外线照射前（对照）所获得的测量结果。
低浓度烟酸甲酯引起的皮肤红斑仅在ITA≥40度定义的白皙至极白皙皮肤受试者中被检测到。推测是在肤色最深的皮肤中，发射光主要被表皮中的黑色素吸收。否则，紫外线照射后，仅在ITA < 50度定义的白皙至深色皮肤个体中可检测到晒黑。这可以解释为，已知最白皙皮肤受试者为黑素生成受损个体，紫外线刺激只能产生微弱晒黑，本研究未能成功检测到。
