Skin Transparency Research Articles

Evaluation of out-in skin transparency using a colorimeter and food dye in patients with atopic dermatitis

Atopic dermatitis is a disease of skin barrier dysfunction and outside stimuli can cross the skin barrier. To examine a new method for evaluating the outside to inside skin transparency with a colorimeter and yellow dyes. In study 1, a total of 28 volunteer subjects (24 normal and four with atopic dermatitis) participated. After provocation with yellow dye, the skin colour of all the subjects was measured using a colorimeter. The skin transparency index was calculated by the changes of the skin colour to yellow. Other variables of skin function, including transepidermal water loss (TEWL) and stratum corneum hydration, were also measured. In study 2, the skin transparency index was evaluated for a cohort of 38 patients with atopic dermatitis, 27 subjects with dry skin and 29 healthy controls. In study 1, the measurement of skin colour (b*) using tartrazine showed good results. There was a significant relationship between the skin transparency index with tartrazine and the atopic dermatitis score (P = 0.014). No other measurements of skin function, including the TEWL, were correlated. In study 2, the skin transparency index score obtained with tartrazine in the patients with atopic dermatitis was significantly higher than that of the controls and those with dry skin (P < 0.001 and P = 0.022, respectively). However, the TEWL in patients with atopic dermatitis was not significantly higher than that of patients with dry skin and the TEWL in subjects with dry skin was not higher than that of the controls. This method, which used a colorimeter and food dye, is noninvasive, safe and reliable for the evaluation of out-in skin transparency and can demonstrate the characteristic dysfunction in the skin barrier in patients with atopic dermatitis.

Vol. 42, No. 1, pp.16‐21, 2008 Decrease in the skin transparency induced by protein carbonylation in the stratum corneum

It has been reported in recent years that the carbonyl modification of protein plays a part in various diseases. The existence of the protein carbonylation in the stratum corneum also came to be known in the last few years, but the effect on the properties of the stratum corneum including the skin appearance was not clarified. In this study, we examined the influence of protein carbonylation in the stratum corneum to provide helpful information for skin care products focusing on transparency of the stratum corneum. Firstly, we developed a method to assess the protein carbonylation level numerically by the image analysis of tape‐stripped stratum corneum reacted with a fluorescent hydrazide. The level of stratum corneum carbonylation of the sun‐exposed site (face) was higher than that of unexposed site (upper arm), and the surface part of the stratum corneum showed a higher level of carbonylation compared with the deeper layer. Stratum corneum carbonylation was induced by in vitro UV irradiation. In addition, it was shown that the skin transparency score was significantly low in the woman with high level of protein carbonylation in the stratum corneum of the cheek. An experimentally carbonylated stratum corneum sheet in vitro became opaque. Among the amino acids investigated, L‐lysine was the most effective to prevent carbonylation of the stratum corneum ex vivo. Moreover, L‐lysine inhibited the decrease in the skin transparency caused by experimental carbonylation of the stratum corneum in the human skin. These results suggest that preventing the carbonylation of the stratum corneum due to adverse effects from the environment by l‐lysine could improve the skin transparency.Keywords: stratum corneum, protein carbonylation, appearance, skin transparency, l‐lysine, amino acids, fluorescent hydrazide, tape‐stripping

Hormonal regulation of female nuptial coloration in a fish

Physiological color change in camouflage and mating is widespread among fishes, but little is known about the regulation of such temporal changes in nuptial coloration and particularly concerning female coloration. To better understand regulation of nuptial coloration we investigated physiological color change in female two-spotted gobies ( Gobiusculus flavescens). Females of this species develop an orange belly that acts as an ornament. The orange color is caused by the color of the gonads combined with the chromathophore based pigmentation and transparency of the skin. Often during courtship and female–female competition, a rapid increase in orange coloration, in combination with lighter sides and back that increases skin and body transparency, gives the belly an intense ‘glowing’ appearance. To understand how this increased orange coloration can be regulated we analysed chromatic and transparency effects of neurohumoral agents on abdominal skin biopsies in vitro. We found prolactin and α-melanocyte stimulating hormone (MSH) to increase orange coloration of the skin. By contrast, melatonin and noradrenaline increased skin transparency, but had a negative effect on orange coloration. However, mixtures of melatonin and MSH, or melatonin and prolactin, increased both orange coloration and transparency. This effect mimics the chromatic ‘glow’ effect that commonly takes place during courtship and intra sexual aggression. Notably, not only epidermal chromatophores but also internal chromatophores lining the peritoneum responded to hormone treatments. There were no chromatic effects of the sex steroids 17β-estradiol, testosterone or 11-ketotestosterone. We hypothesize that similar modulation of nuptial coloration by multiple hormones may be widespread in nature.

角層タンパク質のカルボニル化による肌透明感の低下

角層タンパク質のカルボニル化による肌透明感の低下

Feasibility of Different Capillaroscopic Measures for Identifying Nailfold Microvascular Alterations

To ascertain the most reliable and relevant capillaroscopic measurements of nailfold videocapillaroscopy (NVC) by analyzing their inter- and intraobserver agreement and predictive value. We studied 217 subjects (110 with Raynaud's phenomenon under ongoing evaluation, and 107 with connective tissue diseases) by evaluating the number of capillaries, intercapillary distances, avascular areas, capillary disorganization, capillary loop length, capillary width, percentage of minor abnormalities (tortuous, crossed, or enlarged capillaries), and major abnormalities (giant, bushy, meandering, or branching capillaries), microhemorrhage, skin transparency, and subpapillary plexus visibility. Every finger of both hands was examined. All of the measurements were made by 2 observers under blinded conditions. A total of 877 nailfold images were analyzed. The number of capillaries/mm, interpeak distance, and avascular areas were poorly discriminant, with no statistical differences between their areas under the receiver operating characteristic curve; their reproducibility and repeatability were good, except for the intercapillary distance. Minor abnormalities were observed in 75% of the cases and major abnormalities in 34%; the inter- and intraobserver agreement concerning the major abnormalities was almost perfect. There was very good inter- and intraobserver agreement regarding the analysis of capillary disorganization and hemorrhages. This study shows that NVC can be useful in quantitatively and reproducibly recording various parameters. We suggest that combining the parameters showing the greatest reliability and prognostic value may be the best means of analyzing NVC images.

Methodology for Evaluation of Skin Transparency and the Efficacy of an Essence That Can Improve Skin Transparency

Transparency of the skin is an important factor for realizing beautiful skin, but there is only a visual sensory evaluation method by a beauty specialist. It is unclear how skin physiological characteristics can give transparency. Our purpose is to establish an objective method for evaluating the transparency of the skin and to develop a special cosmetics product which can enhance skin transparency, after investigating the mechanism of the skin characteristics which yield transparency. We developed an optical instrument that could independently measure a diffuse reflection as well as a specular reflection by assembling a polarizing filter in a gonio-spectrum photometer. We analyzed the relationship among skin transparency, specular reflection light and diffuse reflection light. It was shown that there was a strong positive correlation between the skin transparency and the intensity of the diffuse reflection light (r = 0.699) and no correlation between the skin transparency and the intensity of the specular reflection light (r = 0.190). The results of partial least squares (PLS) analysis of the skin transparency and the skin physiological characteristics showed that a highly transparent skin has a fine skin surface texture with a high hydration of stratum corneum, a low melanin content and a low hemoglobin content. On the basis of these results, we developed an essence that can improve skin texture and blood flow, reduce melanin content, and increase the moisture in the stratum corneum. After eight weeks’ usage of this product by consumer panels (n = 30), it was confirmed that the skin transparency was improved by the increase of the intensity of the diffuse reflection light by gonio-spectrum photometer measurement and by consumers’ self-assessment.

肌の透明感測定とその対応化粧品の有用性評価

Transparency of the skin is an important factor for realizing beautiful skin, but there is only a visual sensory evaluation method by a beauty specialist. It is unclear how skin physiological characteristics can give transparency. Our purpose is to establish an objective method for evaluating the transparency of the skin and to develop a special cosmetics product which can enhance skin transparency, after investigating the mechanism of the skin characteristics which yield transparency. We developed an optical instrument that could independently measure a diffuse reflection as well as a specular reflection by assembling a polarizing filter in a gonio-spectrum photometer. We analyzed the relationship among skin transparency, specular reflection light and diffuse reflection light. It was shown that there was a strong positive correlation between the skin transparency and the intensity of the diffuse reflection light (r = 0.699) and no correlation between the skin transparency and the intensity of the specular reflection light (r = 0.190). The results of partial least squares (PLS) analysis of the skin transparency and the skin physiological characteristics showed that a highly transparent skin has a fine skin surface texture with a high hydration of stratum corneum, a low melanin content and a low hemoglobin content. On the basis of these results, we developed an essence that can improve skin texture and blood flow, reduce melanin content, and increase the moisture in the stratum corneum. After eight weeks’ usage of this product by consumer panels (n = 30), it was confirmed that the skin transparency was improved by the increase of the intensity of the diffuse reflection light by gonio-spectrum photometer measurement and by consumers’ self-assessment.

The structure of consciousness and the physiological characteristics of the skin regarding skin transparency: comparison between the young and middle-aged and elderly women

Transparency of the skin is an important keyword that is frequently used in questionnaires related to the female skin condition and skin consciousness, as well as an index for ‘before and after’ comparisons of the effect of cosmetics. However, the concept of ‘transparency’ has not been concretely defined. In the present study, we investigated the importance of ‘transparent skin’ and the relationship between transparency and other expressions for skin condition comparing the young with middle-aged and elderly women. Furthermore, we also analyzed the correlation between the subjective assessment score of transparency of panels made by evaluators and the skin physiological parameters of those panels, and compared the difference of their relationship when the young and middle-aged and elderly women were employed as evaluators. Regarding the consciousness of the young women, the importance of ‘transparent skin’ was ranked in the top position while ‘skin roughness’ was the chief worry of the middle-aged and elderly women. On the other hand, both age groups indicated that transparent skin is a complex concept composed of skin texture, color, and moisture. Analysis of the relationship between the subjective assessment and the skin physiological parameters showed that the uneven dispersion of b in the skin color (standard deviation), the water content of stratum corneum, and the skin surface configuration (depth of furrows, amount of furrows) closely correlated with the judgment of skin transparency in the young group, in contrast to the uneven dispersion of L and a in the skin color (standard deviation) in the middle-aged and elderly women. These results suggest that there may be no differences between the different age groups in the linguistic concept of transparency, while there may be differences in the physiological characteristics of skin that are utilized in making the judgment of transparency.

The quantification of skin transparency.

A new method for quantifying the transparency of skin using an adapted pair of Harpenden's Calipers is described. A constant for each skinfold's ability to transmit light, the H factor, is calculated and this shows a steady decline with age.

Cytoplasmic inclusion body in the epidermal cells of normal and transparent silkworm larvae

The cytoplasm of the epidermal cells of the silkworm ( Bombyx mori L.) with normal opaque skin includes many lens-shaped cell organelles which usually contain a very electron-dense substance, whereas the epidermal cells of transparent mutant od include only small amounts of the electron-dense substance. The contained substance seems to be at least partly composed of urates, and it reduces silver nitrate strongly. In the transparent larvae, these cell organelles are abundant in the younger stages of development but seem to be functionless and are destroyed in the later state. The number of such inclusion bodies may be responsible for the apparent difference of skin transparency in the silkworm.

Relationship between Skin Color or Skin Transparency of Silkworm Larvae and Chromogranules in Hypodermal Cells

Relationship between Skin Color or Skin Transparency of Silkworm Larvae and Chromogranules in Hypodermal Cells