Differences in susceptibility to oxidative stress in the skin of Japanese and French subjects and physiological characteristics of their skin.

BACKGROUND: Many researchers have studied differences in conditions of ethnic skin using biophysical measurements. However, few studies to date have focused on the antioxidative capacity of the skin. METHODS: We measured two parameters of oxidative stress in the stratum corneum, catalase activity and protein carbonylation of the stratum corneum (SCCP), in two ethnic groups, Japanese and French subjects, to characterize the susceptibility to oxidative stress. We also measured several physiological parameters at three different skin sites, two sun-exposed sites (cheek and dorsal aspect of the hand) and a sun-protected site (inner upper arm), in both ethnic groups. RESULTS: Transepidermal water loss (TEWL), the size of corneocytes and skin color showed differences between sun-exposed and sun-protected sites regardless of ethnicity. Regarding ethnic differences, catalase activities and parameters of skin hydration and barrier function of Japanese subjects were higher than those of French subjects. However, SCCP values showed a trend contrary to catalase activity. The difference in the b* value indicated that the melanin content of Japanese skin was higher than that of French skin. Pearson's correlation analyses showed that catalase activity and SCCP values had weak relationships with water content, TEWL and skin color in both ethnic groups. CONCLUSION: Differences in susceptibility to oxidative stress, namely melanin content and catalase activity in the skin, induce the better skin condition of Japanese compared with French subjects.

The "Sym'Previus" software, a tool to support decisions to the foodstuff safety.

Describing the Sym'Previus project, the software and its deliverable facilities is the aim of this present paper. This software concerns all the partners of the food industry who are involved in the management of food safety and allows food-borne pathogen behaviour in food to be predicted, as function of the environment (nature of the food, manufacturing process, conditions of conservation). This analysis of microbial behaviour has been possible thanks to the progress made in predictive microbiology since the 1980s. Sym'Previus offers to food industry professionals and their partners the possibility of applying this progress, by giving access to a database, to simulation systems and expertise.

Classification of pig myofibres and assessment of post-mortem glycogen depletion according to fibre type by computerized image analysis.

A computer-aided method for muscle fibre type determination and qualitative analysis of glycogen at a cellular level is described. The operational system consists of a microscope, a CCD videocamera, an image analysis card, a colour monitor and a standard workstation computer (32 Mb central memory, 22 mips) running under the UNIX operating system. The programme was developed with 512 × 512 pixel images. Four main steps can be distinguished: digitization, network extraction, network matching and measurement of staining intensities. The data generated for each analysed fibre included, diameter, cross-sectional area, ATPase staining intensity and type. Ten minutes of batch processing and 36-41 min of interactive work were needed to analyse 200-300 fibres. Results have shown that this image analysis system can distinguish four types of myofibres denoted I, IIA, IIB and IIC, on the basis of myosin ATPase sensitivity at three preincubation pH values (4·10, 4·35 and 10·4). Preliminary results have also shown that the image analysis system can be used to measure post-mortem glycogen depletion according to fibre type.

Evaluation of the effects of cosmetic or dermo-pharmaceutical products on cutaneous energy metabolism using the Episkin model of reconstructed epidermis.

This study was implemented to test the Episkin model of reconstructed epidermis in the evaluation of the efficacy of cosmetic or dermopharmaceutical products on cutaneous energy metabolism. The energy metabolism is evaluated by measuring the concentration of intracellular ATP by a method using an ultrasensitive bioluminescent reaction. The work presented compares results obtained in reconstructed epithelium and monolayer primary cultures of human keratinocytes. After application of a hydrosoluble product, the increase in intracellular ATP is identical in a monolayer culture of keratinocytes (+239 +/- 18% versus control) and in Episkin (+248 +/- 21% versus control). An emulsion was also tested on the two models. It is only possible to test the emulsion at a dilution of under 0.05% on a keratinocyte culture, and this means that the real efficacy of the product is underestimated (+145 +/- 18% versus control). The three-dimensional model enables the application of the undiluted emulsion, and the results show an increase in intracellular ATP of +420 +/- 80% versus control: products in final formulation can be tested in normal conditions of use.