Effect of seasonal and geographical differences on skin and effect of treatment with an osmoprotectant: Sorbitol.

Human skin maintains an optimal permeability barrier function in a terrestrial environment that varies considerably in humidity. Cells cultured under hyperosmotic stress accumulate osmolytes including sorbitol. Epidermal keratinocytes experience similar high osmolality under dry environmental conditions because of increased transepidermal water loss (TEWL) and concomitant drying of the skin.

Enzymatically generated hydrogen peroxide reduces the number of acne lesions in acne vulgaris.

A major component to the etiology of acne is the growth and invasion by Propionibacterium acnes. Hydrogen peroxide is an excellent antimicrobial agent but is unstable in most formulations. We have developed a hydrogen peroxide generation system using the enzyme glucose oxidase and glucose.

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.

A novel method to study the skin-lightening effect of topical materials.

Skin without significant dyschromia is an aesthetic requirement for people worldwide. There are several in vitro methods to determine the whitening potential of actives; however, the in vivo testing of skin whiteners is a long and expensive process. We have designed a rapid clinical method to screen potential skin whiteners using a UV-induced skin tan as a model.

A rapid method to clinically assess the effect of an anti-acne formulation.

Historically, clinical evaluation of acne treatment has been based on direct visual assessment and the counting of lesions over a period of several weeks of treatment. However, with advancing technology there has been ever-increasing speed in the effectiveness of these treatments. To successfully assess these faster treatments, acne pathology needs to be evaluated in a shorter time frame.

Neuropeptide (calcitonin gene-related peptide) induction of nitric oxide in human keratinocytes in vitro.

Nitric oxide (NO) is an important signaling molecule in both the central nervous system and the periphery, where it is involved in neurotransmission, vascular and bronchial tone, inflammation, and cutaneous immune function. More recently, NO has been implicated in intracellular signaling and may have a role in cellular differentiation, cytokine expression, and apoptosis. The experiments described herein examined the effect of calcitonin gene-related protein (CGRP), a cutaneous nerve neuropeptide, on NO production in human keratinocytes in vitro.

Effect of systemic hormonal cyclicity on skin.

Fluctuations in estrogen and progesterone during the menstrual cycle can cause changes in body systems other than the reproductive system. We conducted several studies to determine a possible correlation between phases of the menstrual cycle and specific skin properties. Healthy Caucasian women (ages 21-48), who had a typical 26-29 day menstrual cycle, participated in the studies.

Impact of stress of marital dissolution on skin barrier recovery: tape stripping and measurement of trans-epidermal water loss (TEWL).

Background: Psychological stress of marital disruption is associated with significant increases in a variety of psychological and physical disorders. The effect of stress on the immune system is well documented and skin disorders have been reported to exacerbate during stressful situations. This study was designed to observe the effects of stress on skin barrier strength and recovery.

Tonality of suntan vs sunless tanning with dihydroxyacetone.

BACKGROUND/AIMS: Although there is an increasing awareness of the detrimental effects of solar irradiation on skin, a tanned look is still in fashion. To achieve the tanned look without sun exposure various sunless tanning formulations have become available. Most of these contain dihydroxyacetone (DHA) which binds to the proteins of the stratum cornium and imparts a brown color to skin.