Alex Nkengne

Influence of facial skin attributes on the perceived age of Caucasian women

Background and objective  The facial appearance of a person does not always reflect the chronological age; some people look younger or older than they really are. Many studies have described the changes in skin properties (colour, wrinkles, sagging, micro relief, etc.) with age, but few of them have analysed their influence on the perceived age. The primary objective of this study was to assess the contribution of individual skin attributes of the face on the perceived age of Caucasian women. Secondary objectives were to assess the influence of age and gender of graders with regard to the age perception.

Assessing facial wrinkles: automatic detection and quantification

As people mature, their skin gradually presents lines, wrinkles, and folds that become more pronounced with time. Skin wrinkles are perceived as important cues in communicating information about the age of the person. Nowadays, documenting the facial appearance through imaging is prevalent in skin research, therefore detection and quantitative assessment of the degree of facial wrinkling can be a useful tool for establishing an objective baseline and for assessing benefits to facial appearance due to various dermatological treatments. However, few image‐based algorithms for computationally assessing facial wrinkles are present in the literature, and those that exist have limited reliability.

Detection of melanoma from dermoscopic images of naevi acquired under uncontrolled conditions

Background and objective: Several systems for the diagnosis of melanoma from images of naevi obtained under controlled conditions have demonstrated comparable efficiency with dermatologists. However, their robustness to analyze daily routine images was sometimes questionable. The purpose of this work is to investigate to what extent the automatic melanoma diagnosis may be achieved from the analysis of uncontrolled images of pigmented skin lesions.

Effect of Aging on DNA Excision/Synthesis Repair Capacities of Human Skin Fibroblasts

TO THE EDITOR A key factor in the skin aging process is the cumulative effects of chronological aging and environmental-based assaults. Endogenous cellular oxidative processes generate reactive oxygen species and reactive polyunsaturated fatty acid derivatives (Lindahl, 1993; Marnett and Plastaras, 2001). These attacks on DNA cause substantial base and sugar damage, and the persistence of such lesions leads to mutations and genome instability. Skin may also suffer from chronic exposure to sun; UV radiation causes oxidative DNA damage and induces photoproducts (mainly cyclobutane pyrimidine dimers and 6-4 photoproducts (Moriwaki and Takahashi, 2008)). Age-related accumulation of somatic damage can thus be worsened by sun exposure, leading to an increased incidence of skin disorders and dramatic acceleration of skin aging (Niedernhofer, 2008). Mammalian cells have evolved several DNA-repair pathways to remove all the categories of DNA base lesions, relying in particular on DNA excision mechanisms. One of these, nucleotide excision repair, removes bulky adducts and is thus an essential mechanism for correcting UV-induced DNA damage (Sarasin, 1999). The base excision repair pathway corrects small base modifications such as oxidized and alkylated bases (Almeida and Sobol, 2007). The importance of repair mechanisms is demonstrated by the hazardous consequences of genetic defects in DNA repair (Friedberg, 2001), but investigating DNA repair with respect to aging remains a challenge. This is due to the complexity of the underlying repair mechanisms as well as to the varying approaches in terms of assays and end points measured (Vijg, 2008). To better understand the relationship between aging and DNA repair, we took advantage of our newly developed multiplexed excision/synthesis assay (Millau et al., 2008) to examine simultaneously, using nuclear extracts, the base excision repair and nucleotide excision repair capacities of human primary fibroblasts derived from healthy donors of different ages. In addition, we investigated changes in DNA repair attributed to chronic sun exposure. A total of 33 healthy Caucasian women were recruited by the Dermscan Group (Lyon, France). Biopsy removal was performed in accordance with the Declaration of Helsinki Principles Guidelines after approval for the study had been given by a medical ethics committee and written consent obtained from the donors. The volunteers were classified into three groups by age (group 1: mean age1⁄425 years, range 20–33, n1⁄49; group 2: mean age1⁄446 years, range 40–50, n1⁄4 9; group 3: mean age1⁄4 65 years, range 61–68, n1⁄415). All subjects were nonsmokers, had phototype II or III skin, declared no excessive exposure to sun or UVA, had no cutaneous pathology, and were not receiving medical treatment. Fibroblast cultures were established from outgrowth of two 3 mm punches taken on the volar forearm (photoexposed area) and the upper inner arm (photoprotected area). Cells were harvested during the exponential phase of growth and stored frozen in liquid nitrogen at passage 5. Nuclear extracts were prepared as described by Millau et al. (2008). For each sample, excision/ synthesis repair reactions were run for 2.5 hours at 30 1C at a final protein concentration of 0.15 mg ml , along with 1 mM adenosine triphosphate and 1.25 mM dCTP-Cy5 (Amersham, Little Chalfont, England), on damaged plasmid microarrays prepared as described by Millau et al. (2008) (see Supplementary Data and Supplementary Figures online for experimental details and nuclear extract features). The microarrays were prepared using Hydrogel slides (Perkin Elmer, Courtaboeuf, France) spotted with unmodified control plasmids together with five plasmid families containing serial amounts of typical lesions (three dilutions per plasmid family). Lesions present on the support were formed by specific physical and chemical treatments: photoproducts (cyclobutane pyrimidine dimers and (6–4)photoproducts), 8-oxoguanine, alkylated bases, abasic sites, and pyrimidine glycols. Total fluorescence intensity related to the fluorescence incorporated into plasmids was the parameter used for calculations (Genepix 4200A scanner, Axon GenePix, Molecular Devices, Sunnyvale, CA). A total fluorescence intensity value was calculated for each lesion type by adding the values for the corresponding replicates. Hence, each microarray generated one value per lesion type. The mean of the two values obtained per sample and per lesion type were used for statistical purposes. Assessment of the mean fluorescence intensity (shown with the corresponding standard error for each lesion type in Figure 1) revealed a decrease in excision/ synthesis activity with age, irrespective of the repair pathway considered. Statistical analysis (general linear model (Minitab V14 software, The MathWorks, Natick, MA) was performed on these latter data from 31 samples: photoprotected and photoexposed cells from the same subject. The general linear model was used to estimate the influence of age

Development and validation of a photonumeric grading scale for assessing lip volume and thickness.

Background  Currently, there is the need of a validated grading scale for assessing lip volume/thickness.

Evaluation of the cellulite using a thermal infra‐red camera

Cellulite is usually related to alterations of the microcirculation. Measuring the skin temperature is a mean to assess the skin microvascular plexus.

Biophysical properties of striae distensae evaluated in vivo using non‐invasive assays

Striae Distensae (SD) or stretch marks are manifestations of epidermal atrophy that occurs after tissue tearing due to rapid growth or over‐stretching and are characterized by distinct microstructural features. The objective of this in vivo study was to investigate the biophysical properties of SD lesions, including skin barrier function, skin surface hydration, mechanical properties, and chromophore concentrations, compared to normal adjacent skin.

Striae distensae are characterized by distinct microstructural features as measured by non‐invasive methods in vivo

Stretch marks or striae distensae (SD) are characterized by epidermal atrophy following repeated over‐stretching of the skin tissue. The objective of this study was to investigate the skin texture and microstructure of SD lesions compared to those of normal adjacent skin in vivo using non‐invasive methods.

The skin aging index: a new approach for documenting anti‐aging products or procedures

The overall appearance of an aged skin is characterized by a combination of several attributes such as wrinkles, brown spots and sagging. Our objective was to develop and validate a statistical framework to assess the overall anti‐ageing benefits of products/procedures.

Age prediction using a supervised facial model

Facial rejuvenation has driven a lot of research in the field of dermatology and plastic surgery, leading to many medical procedures. This paper proposes an age prediction method that could be used to better understand the ageing process and to evaluate the benefits of a rejuvenating treatment, for example. A supervised Facial Model (SFM) is built using Partial Least Squares regression (PLSR) to capture and summarize age related changes from a database of front face images. The model describes the changes related to the shape and proportions of facial features, color and texture of the face. Experimental results from a database of 173 Caucasian women pictures demonstrate that the model matches human perception.