Building Blocks of the Protective Suberin Plant Polymer Self-Assemble into Lamellar Structures with Antibacterial Potential.

The protection of terrestrial plants from desiccation, mechanical injury, and pathogenic invasion is achieved by waxes and cutin polyesters on leaf and fruit surfaces as well as suberin polymers that are embedded in the cell walls of roots, but the physicochemical principles governing the organization of these biological composites remain incompletely understood. Despite the well-established enzymatic mediation of suberin formation in the skins of potato tubers, cork oak trees, and internal plant tissues, the additional possibility of self-assembly in this system was suggested by our serendipitous finding that solvent extracts from potato phellem tissues form suspended fibers and needles in the absence of such catalysts over a period of several weeks. In the current study, we investigated self-assembly for three-component model chemical mixtures comprised of a hydroxyfatty acid, glycerol, and either of two hydroxycinnamic acids that together typify the building blocks of potato suberin biopolymers.

P NMR Evidence for Peroxide Intermediates in Lipid Emulsion Photooxidations: Phosphine Substituent Effects in Trapping.

Intralipid is a lipid emulsion used in photodynamic therapy (PDT) for its light scattering and tissue-simulating properties. The purpose of this study is to determine whether or not Intralipid undergoes photooxidation, and we have carried out an Intralipid peroxide trapping study using a series of phosphines [2'-dicyclohexylphosphino-2,6-dimethoxy-1,1'-biphenyl-3-sulfonate, 3-(diphenylphosphino)benzenesulfonate, triphenylphosphine-3,3',3''-trisulfonate and triphenylphosphine]. Our new findings are as follows: (1) An oxygen atom is transferred from Intralipid peroxide to the phosphine traps in the dark, after the photooxidation of Intralipid.

Corneobiology and corneotherapy--a final chapter.

The text obtained for this review from Professor Albert Kligman was drawn posthumously from a variety of notes that he had been planning to use to write a review on corneobiology and corneotherapy. It was a review that he had dearly hoped to complete--his final 'magnum opus' with reflections on the subject.

Barrier functions of human skin: a holistic view.

The fascinating topic of skin barrier continues to engage researchers from diverse disciplines both in academia and industry. Much of the information on the basic biology of barrier formation, its ontogeny as well as repair and homeostasis comes from studies on animal models. A smaller number of human studies have validated the usefulness of animal models, while highlighting some essential differences.

Rosacea treatment using the new-generation, high-energy, 595 nm, long pulse-duration pulsed-dye laser.

Background And Objectives: Rosacea results from sun-induced hyper-vascularity of exposed facial skin, often accompanied by acneiform papules and pustules. The pulsed-dye laser has an unparalleled safety record and emits an ideal wavelength for treating the abnormal vessels that occur in rosacea patients. In this study we investigate the ability of the long pulse-duration pulsed-dye laser to improve rosacea.

In vivo determination of the skin atrophy potential of the super-high-potency topical corticosteroid fluocinonide 0.1% cream compared with clobetasol propionate 0.05% cream and foam, and a vehicle.

Purpose: Prolonged topical corticosteroid use is often associated with atrophic skin changes. This trial compared signs of skin atrophy related to 3 super-high-potency corticosteroids: fluocinonide 0.1% cream, clobetasol propionate 0.

Pilot investigation of the hydrating effects of topical acne medications.

Topical therapies are effective in managing acne vulgaris but are associated with local adverse effects such as irritation and dryness. This 4-week pilot study compared skin hydration in 36 healthy adult women randomized to treatment with 1 of 4 topical therapies: 2 different (jar and tube) clindamycin 1%/benzoyl peroxide 5% gels, sodium sulfacetamide 10% lotion, or over-the-counter (OTC) moisturizing cream. Subjects treated with OTC moisturizer or sodium sulfacetamide exhibited decreased water loss, increased water retention, similar or improved levels of skin hydration, and decreased desorption rates.

Evidence that two alkyl ester quaternary ammonium compounds lack substantial human skin-sensitizing potential.

Background: Alkyl ester quaternary ammonium compounds (ester quats) are used extensively in fabric rinse conditioners. It is important to document in the literature the outcome of historical studies that were performed to assess the risk of adverse skin effects associated with their use.

Objectives: (1) To document the outcomes of historical studies performed to evaluate the skin sensitizing potential of two ester quats (the di-[hardened tallow fatty acid] ester of 2,3-dihydroxypropyl-trimethyl ammonium chloride [HEQ] and the dialkyl ester of triethanol ammonium methyl sulfate [TEA-Quat]) and (2) to demonstrate that these ester quats lack marked skin-sensitizing potential in humans, such that they do not present a risk of contact allergy for consumers who use fabric rinse conditioners.

Experimental studies on the nature of sensitive skin.

Background: In the USA, Europe and Japan 40 to 50% of women report that they have sensitive skin, defined as abnormal sub-clinical sensory responses to drugs, cosmetics and toiletries in the absence of visible signs of irritation. Itching, burning, stinging and tightness are the commonest complaints, which mainly afflict women. Manufacturers of skin care products have made available a large variety of products which are designed for persons with sensitive skin.

Soak and smear: a standard technique revisited.

Background: Atopic dermatitis, nummular eczema, chronic hand dermatitis, palmar plantar psoriasis, and xerotic eczema are common inflammatory skin conditions. They may be refractory to conventional topical and even systemic treatment. Little evidence is available that demonstrates the benefits of aggressive topical treatment of patients with these disorders.

Low dose isotretinoin combined with tretinoin is effective to correct abnormalities of acne.

Background: Isotretinoin is well known in the therapy of acne papulopustulosa and acne conglobata. No study has investigated the pathophysiological changes of the skin of acne patients, especially when low dose oral isotretinoin is given in combination with topical tretinoin.

Patients And Methods: 28 patients were treated for 6 months with oral isotretinoin.

Effects of age on human cumulative irritation responses.

A 10-day cumulative irritation test was conducted to evaluate whether or not test subjects 65 years of age and older would rank eleven test materials the same as subjects 18 to 45 years of age The test materials consisted of mild to moderately irritating chemicals. The test articles were ranked similarly for both groups of subjects. Statistical analysis indicated no significant difference between the groups of subjects.

Cutaneous toxicity of chemical irritants on hairless Guinea pigs.

To evaluate the toxicity of irritant chemicals on animal skin, investigators have frequently had to apply high concentrations, owing to the fact that its susceptibility is less than that of human skin. High concentrations are so damaging to tissue that specific effects are obscured on the various layers. The aim of the present study was to elucidate the effects of a variety of irritating chemicals on the skin of hairless guinea pigs.

The 21-day human cumulative irritation test can be reduced to 14 days without loss of sensitivity.

The 21-day cumulative irritation test for assessing the irritancy of topical products and chemicals is a venerable procedure that appears to have become the gold standard for manufacturers. Berger and Bowman in 1982 (1) showed that reducing the exposure to 14 days was less traumatic to the volunteers, less costly, less arduous, and did not affect reliability or the capacity to place the test agents in the proper rank order of irritancy. In the current study we compared (a) the 21-day cumulative irritation test, (b) the 14-day cumulative irritation test, and (c) the 14-day test with every-other-day patching.

Comparative efficacy of clindamycin and benzoyl peroxide for in vivo suppression of Propionibacterium acnes.

Background: Benzoyl peroxide and clindamycin are the two most widely prescribed topical antimicrobials in the treatment of acne.

Aim: To compare the antimicrobial efficacy, in vivo, of benzoyl peroxide and clindamycin against Propionibacterium acnes.

Methods: Two groups of 10 subjects each, with comparable mean P.

What is the 'true' function of skin?

Conventional textbook wisdom portrays the skin as an organ that literally enwraps whatever each of us stands for as a more or less functional, individual member of the mammalian species, and has it that the skin primarily establishes, controls and transmits contacts with the external world. In addition, the skin has long been recognized to protect the organism from deleterious environmental impacts (physical, chemical,microbiological), and is well-known as crucial for the maintenance of temperature, electrolyte and fluid balance. Now, ever more studies are being published that show the skin to also operate as a huge and highly active biofactory for the synthesis,processing and/or metabolism of an astounding range of e.

Polarized light photography and videomicroscopy greatly enhance the capability of estimating the therapeuic response to a topical retinoid (adapalene) in acne vulgaris.

Assessment of improvement in acne lesions following treatment is often based on clinical evaluation and photographs. However, limitations are associated with this sublective evaluation, making it difficult to accurately review individual acne lesions and to observe early response to therapy. Conventional photographs do not allow us to visualize small lesions, and it can be difficult to differentiate inflammatory lesions as papules or small nodules.