Egawa Mariko, Ozaki Yukihiro, Takahashi Motoji
Shiseido Research Center (Shin-Yokohama), Tsuzuki, Yokohama 224-8558, Japan.
Skin Res Technol. 2006 May;12(2):126-32. doi: 10.1111/j.0909-752X.2006.00141.x.
BACKGROUND/AIMS: Recently, there has been increasing awareness regardless keeping nails in good condition. Maintenance of an optimum water level in the nail plate is very important since water content affects the nail condition. However, a simple method for in vivo measurement of water in the nail plate quantitatively has not been reported. In this study, we applied Near infrared spectroscopy (NIR)-based prediction of water content of the cut nail plate to in vivo measurement to obtain information about the seasonal change of water in the fingernail.
Diffused reflectance spectra of the nail plate of the fingernail were collected in the NIR region with an NIR spectrometer in vivo both in summer and winter from the same 15 Japanese female subjects. The water content of the nail plate in vivo was calculated from the NIR spectrum using partial least square regression analysis.
It was possible to apply NIR-based prediction of water content of the cut nail plate to in vivo measurement. We also found that the water content of the nail plate varied from person to person but not with the finger of the individual. The average water content of the nail plate was significantly lower in winter than in summer (P<0.05). In summer, the water content in the double-layered nail tended to be higher than a nail in good condition (P<0.1) and significantly lower in the split nail (P<0.05). There was no significant difference between the groups in winter. On the contrary, the amount of water absorption tended to vary depending on the nail condition. A large amount of water was absorbed in the double-layered nail and a small amount in the split nail both in summer and winter.
The water content of the nail plate of fingernail was predicted by in vivo measurement using NIR spectrometry. Physiological information of the nail in vivo, such as aging and other disorders could be obtained by this method.
背景/目的：近来，人们对保持指甲健康状态的关注度日益提高。由于水分含量会影响指甲状况，因此在指甲板中维持最佳水分水平非常重要。然而，尚未有关于在体内定量测量指甲板水分的简单方法的报道。在本研究中，我们将基于近红外光谱（NIR）的修剪指甲板水分含量预测应用于体内测量，以获取有关指甲中水分季节性变化的信息。
在夏季和冬季，使用近红外光谱仪在体内收集了来自15名日本女性受试者相同手指的指甲板的漫反射光谱。使用偏最小二乘回归分析从近红外光谱计算体内指甲板的水分含量。
可以将基于近红外光谱的修剪指甲板水分含量预测应用于体内测量。我们还发现，指甲板的水分含量因人而异，但与个体的手指无关。冬季指甲板的平均水分含量明显低于夏季（P<0.05）。在夏季，双层指甲中的水分含量往往高于健康指甲（P<0.1），而在劈裂指甲中则明显较低（P<0.05）。冬季两组之间没有显著差异。相反，吸水量往往因指甲状况而异。在夏季和冬季，双层指甲中吸收大量水分，而劈裂指甲中吸收少量水分。
通过使用近红外光谱法进行体内测量来预测指甲板的水分含量。通过这种方法可以获得指甲在体内的生理信息，例如老化和其他疾病。
