高田 定樹

Background/purpose Detailed information on the mechanism by which surfactants affect the skin barrier function is still scarce. We investigated the contribution of protein denaturation to the effect of surfactants on barrier function. Methods The Transmission Index method, which evaluates the actual effect of surfactants on barrier function, was combined with a microplate assay measuring protein denaturation activity. The correlation between the TI value and the reciprocal of the median effect concentration (1/EC50) was analyzed for 19 surfactants. The contribution of protein denaturation to the effect of surfactants was discussed based on the 1/EC50 per TI value. Results A few surfactants showed high TI value. Nonionic surfactants had no effect. The EC50 varied without certain trend. For amino acid-based surfactants, there was a gradual inverse correlation between the TI value and the 1/EC50. Conclusion The difference in the alkyl structure and the ion source affected the skin barrier function. Protein denaturing activity of the surfactant was not a critical factor. This suggests that the effect on intercellular lipids was the major factor. However, the magnitude of the contribution of protein denaturation activity varied depending on the surfactant, suggesting that each surfactant has a different mechanism of influence on skin barrier function.

Anionic surfactants are commonly used as detergents and emulsifiers. However, these compounds are potent skin irritants. In this study, we evaluated the effect of the alkyl structure of anionic surfactants on the skin barrier function using the transmission index (TI) method. The TI method is used to measure the skin penetration rate of drugs. Sodium soaps of C18 fatty acids with different structures were evaluated. Sodium laurate was used as the control. In addition, microscopic observations of the skin tissue treated with different soaps and controls were performed to study the mechanism of skin permeation. Results showed that unsaturated fatty acid soaps exerted the most potent effect on the skin barrier function and saturated fatty acid soaps exerted the least effect; saturated branched fatty acid soap had an intermediate effect. This could be attributed to the differences in the melting points of different fatty acids. In addition, unlike lauric acid soap, C18 fatty acid soap did not cause morphological changes in the skin tissue. Thus, differences in the alkyl structure of fatty acids resulted in differences in the effect of fatty acid soaps on the skin barrier function. The mechanism was presumed to be an effect on intercellular lipids.

Elderly people show a decline in the ability to decode facial expressions, but also experience age-related facial structure changes that may render their facial expressions harder to decode. However, to date there is no empirical evidence to support the latter mechanism. The objective of this study was to assess the effects of age on facial morphology at rest and during smiling, in younger (n = 100; age range, 18-32 years) and older (n = 30; age range, 55-65 years) Japanese women. Three-dimensional images of each subject's face at rest and during smiling were obtained and wire mesh fitting was performed on each image to quantify the facial surface morphology. The mean node coordinates in each facial posture were compared between the groups using t-tests. Further, the node coordinates of the fitted mesh were entered into a principal component analysis (PCA) and a multifactor analysis of variance (MANOVA) to examine the direct interactions of aging and facial postures on the 3D facial morphology. The results indicated that there were significant age-related 3D facial changes in facial expression generation and the transition from resting to smiling produced a smaller amount of soft tissue movement in the older group than in the younger group. Further, 185 surface configuration variables were extracted and the variables were used to create four discriminant functions: the age-group discrimination for each facial expression, and the facial expression discrimination for each age group. For facial expression discrimination, the older group showed 80% accuracy with 2 of 66 significant variables, whereas the younger group showed 99% accuracy with 15 of 144 significant variables. These results indicate that in both facial expressions, the facial morphology was distinctly different in the younger and older subjects, and that in the older group, the facial morphology during smiling could not be as easily discriminated from the morphology at rest as in the younger group. These results may help to explain one aspect of the communication dysfunction observed in older people.

Anionic surfactants are often used for cleaning and pharmaceutical purposes because of their strong surfactancy and foaming property. However, they are rarely ingested orally, the skin is a part of the human body most affected by surfactants. Barrier function of the skin is very strong, but the anionic surfactants can cause serious damages to it. Recently, amino acid-based surfactants have attracted attention as a safer option owing to their biocompatibility. Cytotoxicity examinations revealed that the amino acid-based surfactants are superior to sulfate-based surfactants. However, a systematical and comprehensive study related to the effect of these surfactants on skin barrier function has not yet been reported. In this work, skin permeation test using the skin of hairless mice and HPLC method is carried out. The material transmission speed through skin in a steady state was different between each surfactant treatment. We performed a comprehensive analysis of the effect of surfactants on skin barrier function and defined Transmission Index as an index for the degree of effect of surfactants. Glutamate series amino acid-based surfactant were effective to Transmission Index and we guessed the cause was due to adsorption. Based on the finding this study, we suggest using adsorptive property as a measure to the effect on the skin barrier function.

In most cases, a meal cannot be finished with a single bite and sip. During eating and drinking, consumers receive dynamic food perceptions from sensory attributes in foods. Thus, we performed multi-sip time-intensity (TI) evaluation of sensory attribute. In each of ten trials, the participant evaluated continuously the intensity of retronasal aroma for 60 s after swallowing oolong tea. We compared the TI parameters (I-max: maximum intensity, T-max: time point at which intensity reached the maximum value, AUC: area under the TI curve, D-plateau: duration between the first and last time points with values exceeding 90% of the maximum intensity, R-inc: rate of intensity increase between the first time points with values exceeding 5% and 90% of the maximum intensity, and R-dec: rate of intensity decrease between the last time points with values exceeding 5% and 90% of the maximum intensity) and TI curves among the ten trials, and approximated each TI curve with an exponential model. Some TI parameters (I-max, T-max, AUC, and R-inc) differed significantly between the first and subsequent trials. The TI curve was significantly lower in the first trial than in the subsequent trials, and TI curve during the time from starting the evaluation to reaching maximum intensity was significantly lower in the second trial than in the subsequent trials. The time constant of the fitted exponential function revealed that the decay of retronasal aroma intensity was slightly faster in the second through fourth trials than in the first and the fifth through tenth trials. These results indicate that olfaction might be more perceptive while consumers sip a cup of the beverage.

The present study examined the effects of facial movements on impressions of facial appearance during dynamic smiling. The participants (80 women) rated the 68 women in the videos, posing with a smile, in terms of attractiveness, likability, and beauty on a 5-point scale. The displacements of the sides of both the cheeks and mouth areas in each video were measured using the optical flow method. Five time points were chosen from time series data that had been divided into four equal intervals. T-tests were applied to analyze the differences in displacements and velocities between the higher- and lower-rated-stimulus groups. The results indicate that the magnitudes of the initial displacements and the acceleration of the initial velocities were most important in creating a positive impression of dynamic smiles. The results also show that there are both common and specific relationships between facial movements and impressions of facial appearance.

Although the color measurement of facial skin becomes more common in dermatology and cosmetics, little is known about the relationship between subjective color perception and colorimetric values in facial skin. In this study, the possible relationships among perceived whiteness and the metric lightness, chroma and hue angle of Japanese females' facial skin color were investigated. First, the perceived brightness of the facial skin of Japanese females was evaluated visually and compared with metric lightness, chroma and hue angle, and the effect of hue and chroma on the perceived brightness was discussed. Second, a psychophysical experiment on the whiteness of the facial images and synthesized skin color plate images was conducted for examining the effect of hue and chroma on the perceived whiteness more precisely and independently. The results of two experiments showed that in regard to the facial skin color of the Japanese female, metric lightness disagrees with perceived whiteness or brightness in a narrow lightness range. The reddish facial skin color appeared brighter or whiter than that of a yellowish one in high lightness regions, and the low-chroma facial skin color appeared brighter or whiter than a high-chroma one. However, in the color plate images, a change in perceived whiteness by hue could not be confirmed, and the change in perceived whiteness by chroma was weaker than that from facial images. These results indicated that a higher-level process of face recognition affected whiteness perception, and the criterion of facial skin whiteness was determined by facial skin color distribution. (c) 2011 Wiley Periodicals, Inc. Col Res Appl, 2011;

認知症等の症状を持つ高齢者を対象にハンドマッサージの効果の生理・心理的側面について、脳波と心拍の動態より評価することを試みた。軽度認知症女性8名(平均年齢79.4歳)を対象とした。脳波と心拍の測定は、ハンドマッサージの直前と直後にマッサージを行った部屋で実施した。ハンドマッサージによる脳波の変化をDIMENSION解析を行ったところ、8名中5名にマッサージ後に値が正常値に近づいた。NATによる解析を行ったところ、マッサージ後に基準に近い脳波変動が見られた。マッサージ前と比較して、マッサージ後は有意に心拍数が減少し、RR間隔は、マッサージ後に有意に増大した。ハンドマッサージにリラクセーション効果があると考えられ、高齢者の心身に効果的に働きかけ、良好な変化をもたらす可能性が示された。

化粧をすると認知症高齢者の表情が豊かになる、リハビリに意欲的になるなど良好な変化をもたらすことが報告されている。本研究では、脳波を用いて化粧効果の定量的評価を試みた。対象は、高齢者施設入居女性47人(年齢82.6±6.5歳、健常〜中等度認知症)、化粧は約50分間実施した。測定は化粧の直前直後に行い、解析には従来研究で用いられているDIMENSIONおよびNATを用いた。DIMENSION解析の結果、化粧後は化粧前と比較して脳波のパターンが有意に安定化した。また、NAT解析により、化粧前に異常活性を示した部位が化粧後には正常に近づくこと、後頭部を中心とした領域で変化が大きいという特徴が見いだされた。これらは、不安定となったニューロン活動を化粧が安定化すること、化粧が部位特異的にニューロン活動を変化させることを示唆している。今後さらに検討を進め、化粧がもたらすリハビリテーション効果に対する信頼性向上に結びつけたい。(著者抄録)

It is considered that the surface structure of human skin changes with age, affecting the appearance of skin. However, the effect of skin structure on its appearance has not yet been clarified. In this study, we measured the geometric structure of the skin of eight women in the age group of 21 to 45 years using the latest confocal scanning laser microscope, and clarified the change in skin structure with age. In addition, based on the geometric data of the skin structure, we numerically investigated the optical characteristics of the skin surface by using a numerical model developed by us. Numerical results reveal that the optical characteristics of skin surface do not depend on the age-induced change in the skin structure very much.

Cosmetic therapy can improve quality of life (QOL) in elderly people. While qualitative observations have shown that cosmetic therapy enhances the expressive and communicative abilities of elderly people, there is relatively little quantitative data regarding the effect of cosmetic therapy. Therefore, this study evaluated the effects of cosmetic therapy on brain activity using measures of electroencephalogram (EEG) pattern abnormalities, including Diagnosis Method of Neuronal Dysfunction (DIMENSION), Neuronal Activity Topography (NAT) and Power Variance Function (PVF). Subjects comprised 43 elderly women living in homes for the elderly. Analysis showed that cosmetic therapy normalized the electrical distribution on the scalp and decreased the size of regions with abnormal fluctuations. These findings support the use of cosmetic therapy to improve QOL. © 2011 IEEE.

皮膚のふく射伝播は，皮膚を散乱・吸収性をもつ連続媒体と考え，ふく射輸送方程式により取り扱われることが多い．この式を用いる場合，式中の減衰係数，アルベド，散乱位相関数の三つのふく射物性値により，そのふく射伝播が特徴付けられる．ここでは，これまでほとんど計測されていない人の皮膚の散乱位相関数を計測できる手法を提案している．この手法では，放物面鏡とCCDカメラを用いることで，極短時間で皮膚による散乱光の強度分布を計測し，それを基に散乱位相関数を求める．実際に，人工培養した皮膚を対象に，散乱位相関数を推定した．

In silico modeling of smiling motions (maximum lip corner retraction) was achieved using the recorded 3-dimensional motion data of 10 anatomical landmarks on a face for 60 women (30 young adults and 30 middle-aged adults). A total of 55 feature variables were extracted from the motion data to generate a feature vector. Sets of the feature vector and the age category were stored as knowledge in the model. The prediction of the age category (young adult or middle-aged adult) was performed by means of Nm-neighboring search in the model knowledge with the weight coefficient W. The prediction model was successfully optimized to provide the prediction accuracy of 75.3% and the feature elements to well represent the effect of aging on smiling motions were formulated objectively. © 2010 TSI Press.

Human skin texture influences its appearance, and a finely textured skin is considered beautiful. However, we do not know precisely how the skin texture influences its appearance. In this study, in order to clarify the scattering characteristics at the skin surface, we measured the bi-directional reflectance using an optical prism with a skin structure. To understand the measurement results, three numerical models have been developed. The first model considers a large-scale structure of the skin, which is called the "skin texture," and the second model considers the finer structure, called the "microstructure." The third model is a combination of the other two models. The results predicted by the models that consider the microstructure are in good agreement with the measurement results. This reveals that the large-scale skin texture does not affect light scattering by the skin surface, but the microstructure of the skin surface does affect light scattering.

Phantom model of the breast which has actual shape and size has been developed for evaluation of microwave imaging by Chirp Pulse Microwave Computed Tomography (CP-MCT). This phantom model will also be successfully used for hyperthermia experiments using microwaves. This phantom model is consisted of four kinds of tissue mimicking materials, that is, the skin-, breast fat-, muscle-, and tumor-simulators. The principal ingredients of the phantom are water, liquid paraffin, super stuff (TX-150), sugar, and salt. It is easy to simulate permittivity of the real breasts in addition to the shape and size. This is the advantage of this non-homogeneous phantom. CP-MCT is a modality for microwave imaging of a human body using chirp pulse microwaves to extract the component which transmits the straight path between two antennas. Possibility of tumor detection by CP-MCT has been demonstrated by using the higher frequency model of CP-MCT and the non-homogeneous breast phantom.

A sensitive UV spectroscopy system has been developed to evaluate sun protection factor (SPF) values of sunscreen materials. With the system, excellent correlations between the in vitro SPF measured values and skin tests were realized. © 2006 Optical Society of America.

In order to design cosmetics producing the optical properties that are required for a beautiful skin, the radiation transfer in the skin has been numerically investigated by the Monte Carlo method and the effects of skin texture and cosmetics on the radiation transfer have been empirically investigated using an artificial skin. The numerical analysis showed that the total internal reflection suppresses large portion of radiation going out through the skin surface Additionally, the experimental study revealed that skin texture and cosmetics not only diffusely reflect the incoming radiation, but also lead the internally reflected radiation to the outside of the skin. © 2004 Elsevier Ltd. All rights reserved.

Examination of skin color is very important in the clinical diagnosis and cosmetic evaluation. However, visual evaluation is subjective, and objective quantification of skin color may therefore be a valuable supplement to the clinical evaluation. In this paper the design and performance of an instrument for quantifying cutaneous color are discussed. The imaging colorimeter consists of an optical unit equipped with video camera, an image processing unit, and a microcomputer. Combining colorimetry and imaging methods, the acquired image is calibrated and corrected, under several ambient light conditions, providing non-contact reproducible color measurements, free of the errors and the limitations present in conventional colorimeters. The imaging colorimeter appears to be a simple and accurate device for objectively measuring skin color. These features highlight the potential of imaging colorimeters as clinical and research tools for the standardization of clinical diagnosis and for the objective evaluation of treatment effectiveness.

We attempted to analyze the skin color of women from the world using identical apparatuses and under identical conditions. The data was used for developing cosmetic products. The skin colors of a total of 1703 women over the world were measured to clarify the characteristics of skin color. Skin color measurement was done by using a spectrometric colorimeter. We modified the conventional erythema and melanin indices and established new respective indices which can reflect various spectral information of whole visible region. The present results were used to design new cosmetics in consideration of the optical properties of skin.