Appropriate Technologies to Accompany Sunscreens in the Battle Against Ultraviolet, Superoxide, and Singlet Oxygen.

The interaction of ultraviolet radiation with biological matter results in direct damage such as pyrimidine dimers in DNA. It also results in indirect damage provoked by the production of reactive oxygen species (ROS) catalyzed by photosensitizers. Photosensitizers can be endogenous (e.

UV protection afforded by gel-trapped TiO2 particles.

We have developed a technology to incorporate micronized titanium dioxide (TiO(2)), together with antioxidants, in particles of a UV-visible transparent polymer gel. These particles are coated with silica to avoid clustering and the size of the micronized TiO(2) reduces the back scattering of white light. gel-trapped TiO(2) minimizes the oxidative stress exerted by UV radiation, increases the photo-stability of some accompanying ingredients, such as avobenzone.

Modification of skin discoloration by a topical treatment containing an extract of Dianella ensifolia: a potent antioxidant.

Skin hyperpigmentation, and the reactions that precipitate it, have been linked to free radicals by the fact that free radical scavengers or antioxidants can slow that hyperpigmentation. We have screened several hundred plant extracts for antioxidants and discovered one that is both a strong antioxidant and can reduce skin hyperpigmentation. Extracts of Dianella ensifolia contain 1-(2,4-dihydrophenyl)-3-(2,4-dimethoxy-3-methylphenyl) propane (DP), which was found to inhibit the free radical 1-1-diphenyl-2-picryl-hydrazyl (DPPH) with an EC(50) value of 78 mum.

Sunscreens: the impervious path from theory to practice.

The preparation of commercial products able to protect the skin against damage from solar radiation requires safe and photo-stable stable UV-absorbing molecules with high extinction coefficients, prepared with solvents of the appropriate polarities and polarizabilities in formulas which allow the uniform spreading of the UV-absorbing substances. The products should also maintain the ingredients on the top of the skin and provide efficient scavenging activities against singlet oxygen and other directly or indirectly generated reactive oxygen species. Because of the high doses of UV used to test high SPF, simple and reproducible methods are needed to estimate the protection afforded by the product before risking the induction of severe burns to the volunteers, as can occur when the value of the product's SPF is smaller than the expected one.

Gender-linked differences in human skin.

Background: The physiology of body organs can be affected by gender. Skin and skin appendages are influenced by sex hormones.

Objective: This review work has been undertaken to point out the most conspicuous physiological differences observed between men's and women's skin.

Calculation of apparent age by linear combination of facial skin parameters: a predictive tool to evaluate the efficacy of cosmetic treatments and to assess the predisposition to accelerated aging.

The estimated apparent age (EAA) was estimated by a panel of trained experts, for the individuals in a cohort. Twelve independent clinical, biophysical and biochemical parameters measured on facial skin, have been identified by multiple regression analysis, which influence the EAA of a person of chronological age (CA) (under eye lines, clinically assessed crow's feet, age spots, clinically evaluated firmness, forehead lines, pores, lip lines, instrumentally evaluated firmness, instrumentally evaluated crow feet, skin texture, in vivo fluorescence related to proliferation and glycation). An algorithm has been devised to obtain the calculated age score (CAS) in a cohort of 452 female volunteers, as CAS(n) = ∑RCiPi(n) (i = 1-13, n = 1-452 and P13 = 1) where the coefficients Ci are obtained by minimizing the difference EAA - CAS, and Pi(n) are the experimental values of the i-th parameter for the n-th volunteer.

Advancement in skin aging: the future cosmeceuticals.

Aging is a multifactorial process defined as the accumulation of damage. The aging of the skin is characterized by specific clinical end points, the cause of which is not always thoroughly understood. The skin is exposed to environmental aggressions and the reactive oxygen species produced during cellular metabolism.

Morphological changes associated with aging: age spots and the microinflammatory model of skin aging.

Affymetrix gene-expression analysis was performed on mRNAs from involved and noninvolved skin biopsies from three volunteers with Lentigo senilis. Of the 42,000 transcripts scanned, 17 were downregulated (<1.4 times below the control level) and 23 were upregulated (>1.

Ageing, science and the cosmetics industry. The micro-inflammatory model serves as a basis for developing effective anti-ageing products for the skin.

The micro-inflammatory model serves as a basis for developing effective anti-ageing products for the skin

Normal human epidermal keratinocytes treated with 7-dehydrocholesterol express increased levels of heat shock protein.

Human skin, and its isolated cells, respond to insults with a variety of repair and protective mechanisms. One such mechanism is the production of heat shock proteins (HSPs). Heat shock proteins help the other cellular proteins fold correctly into their active three-dimensional structures.

A mechanistic model for the aging of human skin.

The microinflammatory model of skin aging is described. This model accounts for the loss of elasticity, resiliene and flexibility of the dermis, as well as for the appearance of wrinkles and for the thinning of the epidermis which are associated with aging. The lack of appropriate apparatuses for the correct measurements of skin hydration does not allow one to test this model for its predictive capability of the appearance of dry skin with age.