Evaluation of protective and restoring effects of a mixture of silanols on photoaging. Use of a device allowing the quantification of contractile strengths of human fibroblasts after UVA irradiation.

Chronic sun exposure and especially UVA wavelengths are responsible for long-term clinical skin changes such as photoageing and photocancers. The objectives of the present study were to analyse the contractile activity of fibroblasts irradiated with several doses of UVA and to evaluate the preventive, protective and restoring effects of a mixture of monomethylsilanetriol mannuronate and dimethylsilanediol salicylate. The forces generated by fibroblasts in tense collagen lattices were quantified using Glasbox device before and after UVA irradiation and the addition of a mixture of monomethylsilanetriol mannuronate and dimethylsilanediol salicylate. The production of collagen was also evaluated before and after irradiation and with and without the presence of a mixture of monomethylsilanetriol mannuronate and dimethylsilanediol salicylate. A dose of 3 J cm(-2) of UVA showed more than 50% of mortality in fibroblast population after 48 h and significant decreases in contractile forces developed by irradiated fibroblasts and collagen I production. One percentage of a mixture of monomethylsilanetriol mannuronate and dimethylsilanediol salicylate protected fibroblasts from UVA irradiation and made it possible to restore their capacity to the same level as fibroblasts that were not irradiated. It also tended to restore the capacity to synthesize collagen I. These results show that the use of the new device Glasbox makes it possible to evaluate a possible preventive and repairing effect of a cosmetic functional active on photoageing.

A study of the effect of decimal and centesimal dilutions of arsenic on the retention and mobilization of arsenic in the rat.

Having developed a pharmacokinetic method for studying the fate of orally administered arsenious anhydride by a radioactive tracer method, the influence of Hahnemannian dilutions of arsenicum album on the elimination and retention of this toxin in the rat was then investigated. The effects of centesimal (cH) and decimal (dH) dilutions were studied. All the dilutions studied were found to be active. The strongest effects were observed after the administration of dilutions corresponding to a concentration of 10(-14) (14dH and 7cH). Overall, the decimal dilutions augmented the elimination of arsenic more than the centesimals. The observed results were submitted to mathematical analysis. A mathematical model, which confirms that Hahnemannian dilutions have biological effects which are a direct function of the degree of dilution, was developed.