Osamu Osanai

Age-related changes in skin wrinkles assessed by a novel three-dimensional morphometric analysis.

Summary Background A system has been developed whereby the morphology of the skin surface can be evaluated directly in three dimensions. This system employs a non‐invasive device that utilizes white light of halogen origin, and which allows the computation of wrinkle depth and width, and other parameters of skin surface morphology. Using innovative engineering, an optical system has been devised so that light is transmitted via a slit and can be used to measure not only replicas of the skin but also the skin surface directly. The measurement area is 6·4 × 6·4 mm, and the theoretical resolution with a × 50 magnification lens is within 12·5 µm.

Ethnic differences in the structural properties of facial skin

BACKGROUND Conspicuous facial pores are one type of serious aesthetic defects for many women. However, the mechanism(s) that underlie the conspicuousness of facial pores remains unclear. We previously characterized the epidermal architecture around facial pores that correlated with the appearance of those pores. OBJECTIVES A survey was carried out to elucidate ethnic-dependent differences in facial pore size and in epidermal architecture. METHODS The subjects included 80 healthy women (aged 30-39: Caucasians, Asians, Hispanics and African Americans) living in Dallas in the USA. First, surface replicas were collected to compare pore sizes of cheek skin. Second, horizontal cross-sectioned images from cheek skin were obtained non-invasively from the same subjects using in vivo confocal laser scanning microscopy (CLSM) and the severity of impairment of epidermal architecture around facial pores was determined. Finally, to compare racial differences in the architecture of the interfollicular epidermis of facial cheek skin, horizontal cross-sectioned images were obtained and the numbers of dermal papillae were counted. RESULTS Asians had the smallest pore areas compared with other racial groups. Regarding the epidermal architecture around facial pores, all ethnic groups observed in this study had similar morphological features and African Americans showed substantially more severe impairment of architecture around facial pores than any other racial group. In addition, significant differences were observed in the architecture of the interfollicular epidermis between ethnic groups. CONCLUSIONS These results suggest that facial pore size, the epidermal architecture around facial pores and the architecture of the interfollicular epidermis differ between ethnic groups. This might affect the appearance of facial pores.

Age-related discontinuous changes in the in vivo fluorescence of human facial skin

We measured the 325-nm laser-induced fluorescence of the skin of the face and ventral forearm in seventy Japanese female volunteers, and evaluated the effects of age and exposure to sunlight. The subjects were arbitrarily grouped into 10-year age-groups. In slightly exposed areas such as the ventral forearm, the average laser-induced intensity ratio at 390 nm to 430 nm showed no significant differences with the age group. In areas markedly exposed to sunlight such as the corners of the eyes and mouth, the average laser-induced intensity ratio showed a discontinuous decrease with age. These findings suggested that dermal fluorophore changes differ with the skin areas and are affected by sunlight exposure.

In vivo measurement of human dermis by 1064 nm-excited fiber Raman spectroscopy

Background/aims: Although chemical information on the dermis in vivo is highly important in skin research, an efficient method for gathering this information is yet to be developed. Here, we demonstrate that newly developed near‐infrared (1064 nm) excited Raman spectroscopy is a powerful method for chemical analysis of human skin in vivo.

Gender‐dependent differences in degree of facial wrinkles

This study aimed to reveal gender‐dependent differences in the degree of facial wrinkles.

Evaluation of photoaging in facial skin by multiphoton laser scanning microscopy.

Background/purpose: It has been reported that autofluorescence (AF) and second harmonic generation (SHG) generated in the upper dermis are related with skin photoaging. In this study, we assessed the photoaging of facial skin exposed to daily sunlight using in vivo multiphoton laser microscopy to measure AF and SHG.

Development of a novel method to measure the elastic properties of skin including subcutaneous tissue: new age-related parameters and scope of application.

Background/purpose: We have developed a new apparatus to measure the elastic properties of skin without contact using an air blown technique.

A new method for the visualization and quantification of internal skin elasticity by ultrasound imaging.

Background/purpose: Skin elasticity has been assessed previously only in the surface layer. We developed a new method that uses tissue strain imaging (TSI) technology, and the aim of this study was to test this new method to assess internal skin elasticity.

Seasonal and annual variation in the intensity of facial wrinkles

We studied annual, seasonal and gender‐dependent changes in the intensity of facial wrinkles.

Imaging of melanin distribution using multiphoton autofluorescence decay curves.

Background/purpose: Multiphoton fluorescence lifetime imaging (FLIM) is a technique that produces an image based on differences in the decay rate of fluorescence from a sample. Based on this method, the DermaInspect was developed to observe human skin components non‐invasively. In this study, we used the DermaInspect to study melanin in skin.