JOURNAL OF JAPANESE COSMETIC SCIENCE SOCIETY
Online ISSN : 2188-0719
Print ISSN : 1880-2532
ISSN-L : 1880-2532
Current issue
Displaying 1-8 of 8 articles from this issue
Regular Article
  • Rie Hioki, Reika Kobayashi, Yukina Kurumada, Kazuyoshi Seguchi
    2023 Volume 47 Issue 4 Pages 281-287
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    Although oxidation dyes are the most widely used commercial hair dyes, the oxidation mechanisms for product formation and color development of hair dyes have not been completely elucidated.

    According to our previous studies, we investigated the oxidation products and the mechanism of color development of oxidation hair dyes under alkaline conditions by air, which is a mild oxidizing agent. The products acetylated for protection of hydroxyl groups in the indonaphthols against further oxdation were isolated by column chromatography and analyzed by 1H/13C-NMR and high-resolution mass spectroscopy.

    The reactions of substituted p-aminophenols as precursors (Pre) with an equimolar amount of 1-naphthol as a coupler (C) in aqueous solution of ethanol gave indonaphthol derivatives, which formed three types of oxidative coupling products (Pre : C=2 : 1, 1 : 1, and 1 : 2) of both the precursor and the coupler. The reaction rate and the percentage of oxidation products were considered based on the substituent effect of the precursor.

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Lecture
  • Tamio Suzuki
    2023 Volume 47 Issue 4 Pages 288-295
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    I held the 48th Academic Conference of the Cosmetics Society in 2023 as president. The main theme of this conference was “pigments”. This manuscript reports the data we have obtained so far regarding the skin color of Japanese people, which is the subject of the president’s lecture. Our ancestors left Africa around 50,000 to 60,000 years ago and spread to all parts of the world. At this time, the skin color, which was originally dark, became lighter due to the relationship with vitamin D metabolism. In other words, variation in skin color occurred as genes adapted to the environment. We have clarified the genetic factors that determine the diversity of Japanese skin color. The results revealed that some variants of the gene that causes oculocutaneous albinism (OCA) have a large effect on melanin synthesis in the skin and are significantly involved in determining skin color. We also found that variation in skin color determines the risk of developing malignant melanoma. Finally, it was suggested that, as positive selection on genes, selective pressure may be at work to prevent Japanese skin color from becoming too pale and to prevent melanin production from decreasing too much.

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Lecture
  • Izumi Naka, Yusuke Watanabe, Mariko Isshiki, Jun Ohashi
    2023 Volume 47 Issue 4 Pages 296-300
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    In a recent genome-wide association study, seven single nucleotide polymorphisms (SNPs) associated with tanning ability in the Japanese population were identified. To assess the tanning ability of individuals, the present study calculated a sunburn type score (STS), reflecting tanning ability, based on the effect sizes of these SNPs and individual genotypes. The population-averaged STS (PA-STS) for the 47 prefectures of Japan revealed that Fukui, Miyagi, Nagasaki, Fukuoka, Ibaraki, and Tottori prefectures exhibited a tendency towards lighter skin, while Nara, Shiga, Oita, and Kagawa prefectures exhibited a tendency towards darker skin. At the prefecture level, no significant association was observed between PA-STS and factors such as latitude (p-value=0.85, R2=7.7×10−4), average elevation (p-value=0.21, R2=0.034), or July’s maximum UV index (p-value=0.41, R2=0.015). These findings imply that regional variations in skin color among Japanese individuals have not been solely shaped by natural selection. Furthermore, when the mean STS was estimated for 19 Jomon individuals, it was significantly smaller than that of modern Japanese, suggesting that the Jomon people had a darker skin color compared to modern Japanese.

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Symposiums
  • Mitsunori Fukuda
    2023 Volume 47 Issue 4 Pages 301-302
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    Melanocytes contain specialized membranous organelles that synthesize and store melanin pigments. Melanosomes mature through four morphologically distinct stages (I–IV), and they are largely divided into two processes: formation of premelanosome limiting membrane and transport of proteins required for melanin synthesis to premelanosomes by membrane traffic. After the stage I melanosome is formed from an early endosome, PMEL is first transported to the stage I melanosome and forms amyloid-like fibrils, where melanin is deposited at later stages. The resulting fibril-containing melanosome is called as the stage II melanosome, but because of the absence of melanin at this stage it is still transparent. To achieve melanin synthesis and to form black melanosomes (stages III and IV), a variety of membrane proteins, including melanogenic enzyme tyrosinase, cupper transporter ATP7A, and ion channels involved in luminal pH regulation, must be transported to the stage II melanosome by membrane traffic (mainly through endosomal traffic). BLOC-1–3, adaptor proteins, and RAB small GTPases are known to be involved in these membrane trafficking events, and their dysfunctions often cause hereditary oculocutaneous albinism such as Hermansky-Pudlak syndrome. The mature stage IV melanosome is transported from the perinucleus to the tips of dendrites along the cytoskeleton (microtubules and actin filaments) and then transferred from melanocytes to adjacent keratinocytes. The transferred melanosome in keratinocytes is finally transported to the upper side of the nucleus to form the supranuclear melanin cap for protection of DNA from UV irradiation. These melanosome transport processes are regulated by motor protein complexes, and one representative example is the RAB27A–MLPH/SLAC2-A–MYO5A complex in actin-based melanosome transport in melanocytes. Dysfunction of the complex results in impaired melanosome transport, and thereby the complex would be an ideal target for development of cosmetics to prevent skin darkening or gray hair at the melanosome transport level.

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  • Yoko Mizokami
    2023 Volume 47 Issue 4 Pages 303-308
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    Various information about the body and mind, such as health status, age, and emotions, can be obtained through facial color and skin appearance. Therefore, humans have a face-specific recognition mechanism, including specific perceptual characteristics for skin color and brightness. We found that the sensitivity to changes in skin redness (in the direction of hemoglobin increase) was higher than that to changes in skin yellowness (in the direction of melanin increase). We also showed the influence of skin color on facial brightness perception. The brightness of faces with skin color modulated in the reddish and yellowish direction was evaluated by matching the brightness of a reference face image with a constant hue. The results showed that reddish faces appeared brighter than yellowish faces at the same brightness. We conducted a similar experiment on foreign observers and found different trends. However, the facial impression evaluation experiment results showed that Japanese, Thai, and Chinese observers rated reddish faces as brighter. These differences could be related to skin color distribution, culture/environment, and judgment criteria. We also investigated the influence of color on facial expression recognition. We showed that reddish (or increased hemoglobin) faces promoted the recognition of angry facial expressions. In contrast, lighter (or decreased melanin and hemoglobin) faces tended to promote the recognition of happy facial expressions. This suggests that humans use facial color as a cue for facial expression recognition and further implies that these skin-specific perceptions of facial skin would contribute to obtaining information on health status and emotions. The studies showing that the conspicuousness of pigment spots is affected by their number, density, location, contrast with the skin and skin homogeneity will also be introduced. Understanding the perceptual characteristics of skin color and texture will be useful for the makeup and cosmetics field.

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  • Shoji Fukamachi
    2023 Volume 47 Issue 4 Pages 309-313
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    Humans mate with sexually preferable partners. The same goes for other animals, including medaka (Oryzias latipes), a freshwater teleost native to the Far East. This model vertebrate has been a useful platform for studying, for example, genetics and developmental biology, and its results have often provided important clues for understanding humans. Recent researches focusing on its mating behavior have revealed that medaka choose reproductive partners based on visual cues. Two body-color variants, color interfere (ci) and Actb–SLα:GFP (soma), strongly prefer mates of the same strain (i.e., they mate assortatively) under white light, but the preferences are not reproduced under monochromatic light. In addition, the ci and soma medaka with mutations on a part of the cone-opsin genes decrease the sexual preference, likely because of the colorblindness. These results indicate that they sexually prefer colors rather than shapes, scents, or movements. The sexual preference seems to be established during growth and is influenced by the body colors of neighboring fish and one’s own coloration. Once established, the sexual preference is firmly maintained for months, even if the fish repeatedly experience matings with unpreferable partners. These characteristics of sexual preference would share common aspects between medaka and humans, which may aid in understanding and addressing undesirable sexual preferences such as pedophilia, molestation, and voyeurism.

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  • Ken Okamura
    2023 Volume 47 Issue 4 Pages 314-319
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    Vitiligo is an autoimmune disorder targeting melanocytes that significantly impairs patients’ quality of life. Currently, there is no established treatment for this condition. Previous epidemiological and susceptibility gene search studies have revealed the involvement of genetic factors in the onset of vitiligo. In the future, through functional analysis of approximately 50 identified susceptibility genes and genomic regions, further exploration of the pathogenesis of vitiligo and the development of novel treatment methods can be expected. As a preliminary step before conducting functional analysis, the utilization of publicly available eQTL analysis and epigenetics analysis results from databases allows for efficient functional analysis. In this article, based on previous susceptibility gene search studies, I will provide an overview of what developments can be expected in the future, sharing my perspective on the subject.

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Basic Lecture
  • Katsuko Kikuchi
    2023 Volume 47 Issue 4 Pages 320-325
    Published: December 31, 2023
    Released on J-STAGE: January 15, 2025
    JOURNAL FREE ACCESS

    Rosacea is a chronic inflammatory dermatosis for which “trigger” avoidance and proper skin care are essential, along with drug therapy. To avoid irritation, cosmetic products used in daily skin care should be of good quality and hypo-irritation. In Japan, azelaic acid formulations which are used to treat rosacea and acne vulgaris, are available as quasi-drugs also called medicated cosmetics. Cosmetics that correct and camouflage redness may be useful in improving the quality of life of rosacea patients. Rosacea-like dermatitis is a medical condition similar to rosacea caused by topical steroids or other medical agents. Although the causative drugs should be discontinued, rosacea-like dermatitis is thought to be an exacerbation of rosacea caused by those drugs, and treatment and skin care similar to that for rosacea may be useful. Seborrheic dermatitis is a chronic recurrent dermatitis caused by the involvement of Malassezia, an indigenous yeast fungus of the skin. Skin care with cleansing agents containing ingredients that prevent Malassezia growth may be useful in treating seborrheic dermatitis along with drug therapy.

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