Skin protection creams in medical settings: successful or evil?

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The skin landscape following nonoptical capacitance imaging.

Skin capacitance is an electrical property measurable at the level of the stratum corneum. Values are related to the moisture content of the tissue. Using the silicon image sensor technology, it has recently become possible to measure capacitance at 50 microm intervals on the skin surface. The resulting nonoptical picture corresponds to skin capacitance imaging. This novel tool for dermatologists highlights with precision the hollow skin surface patterns, including dermatoglyphics, the patterns of the shallow skin lines, and wrinkles. The topographic heterogeneity in skin surface hydration is made visible. In addition, the sweat gland and follicular openings are disclosed. Skin disorders induced by surfactants or presenting as hyperkeratotic areas, including some neoplasms, may show typical aspects. It is concluded that skin capacitance imaging brings added value to the clinical assessment performed by dermatologists

L'agonie du taratata auprès du clinicien.

peer reviewedLe clinicien est à la croisée des chemins entre la rigueur scientifique et le taratata d’une certaine communication bien moins sérieuse. Dans ce contexte, la recherche de l’objectivité est primordiale dans les études cliniques. Nous résumons les aspects principaux des méthodes de dénombrement, de classement, de mesures paramétriques et d’évaluations sur échelles structurée ou non structurée

Eye and Ultraviolet Light

peer reviewedAll the ocular structures, from cornea to retinal layer, can be damaged by exposure to the light radiations. Acute keratitis combined with conjunctivitis will result from an intensive photic exposure. On the other hand, pterygion more likely represents the consequence of chronic exposure to the ultraviolet rays. Exposure to the ultraviolet rays has been involved in the appearance of the typical yellow pigments of the nuclear cataract. Indeed, the physiopathological mechanisms are now progressively better understood. The progression of retinal degenerations might be influenced by uncontrolled exposure to ultraviolet rays, particularly during childhood. It is therefore useful to protect the eyes against ultraviolet sunrays. Filtering glasses seem to be one of the most effective ways to reach that objective

Patterns of aluminum hydroxychloride deposition onto the skin.

peer reviewedBACKGROUND: Aluminum hydroxychloride (AlCl(3) ) is an antiperspirant. AIM: To revisit the AlCl(3) deposition in vivo and in vitro on glass slides and stratum corneum (SC) harvested by cyanoacrylate skin surface strippings (CSSS). METHODS: Transepidermal water loss (TEWL) was assessed following application of 5% AlCl(3) on the forearms. The AlCl(3) -coated skin, glass slides and CSSS were observed using two ultraviolet light-emitting CCD cameras in order to record changes in specular reflectance related to AlCl(3) deposition. In addition, the corneoxenometry bioassay was performed in order to predict AlCl(3) irritation. RESULTS: AlCl(3) deposited on glass slides looked as linear threads and rings of similar sizes. AlCl(3) deposits on skin were almost restricted inside the microrelief lines and as annular deposits at their crossings where acrosyringia are opening. After daily AlCl(3) applications, deposits extended on the CSSS plateaus. At rest in absence of sweating, TEWL was decreased following AlCl(3) applications. During physical exercise, the TEWL increase was limited on the AlCl(3) areas. CSSS appeared unreactive to AlCl(3) at the corneoxenometry bioassay. CONCLUSION: The similar aspect of AlCl(3) deposits on human SC and on glass slides suggested a physical property of AlCl(3) . Repetitive applications of AlCl(3) increased both the deposit area and the barrier function

Dew point effect of cooled hydrogel pads on human stratum corneum biosurface.

BACKGROUND: Cooled hydrogel pads are used to prevent overheating effects of laser therapy. They do not induce cold injuries to the skin, but their more subtle physiological effects have not been thoroughly studied. PURPOSE: To describe the changes in transepidermal water loss and electrometric properties of the skin surface following application of cooled hydrogel pads. Measurements were performed on normal forearm skin of 27 healthy volunteers and on freshly excised skin from abdominoplasty. METHODS: LaserAid hydrogel pads cooled to 4 degrees C were placed for 15 min on the forearm skin. Measurements of transepidermal water loss (TEWL) and electrometric properties (Corneometer, Nova DPM 900) were performed before application and after removal of the cooled pads. RESULTS: A consistent increase in corneometer units, dermal phase meter (DPM) values and TEWL were recorded at removal of the cooled hydrogel pads. Both the in vivo and in vitro assessments brought similar information. DISCUSSION: The similar changes disclosed in vitro and in vivo suggest that a common physical process is operating in these conditions. The observed phenomenon is opposite to the predicted events given by the Arrhenius law probably because of the combination of cooling and occlusion by the pads. A dew point effect (air temperature at which relative humidity is maximal) is likely involved in the moisture content of the stratum corneum. Thus, the biological impact of using cooling hydrogel pads during laser therapy is different from the effect of a cryogenic spray cooling procedure. The better preservation of the water balance in the stratum corneum by the cooled hydrogel pads could have a beneficial esthetic effect on laser treated areas

The key role of corneocytes in pityrosporoses.

Pityrosporoses encompass various Malassezia-driven conditions. Dandruff and seborrheic dermatitis are members of this family of disorders. Their precise pathomechanisms have not been completely elucidated so far. This review focuses on the role of corneocytes in these disorders. Malassezia yeasts are not evenly distributed at the surface of the stratum corneum. Rather, they are clumped on some corneocytes while other corneocytes in their vicinity are almost free of these microorganisms. The corneocytes heavily coated by yeasts suggest a cell-related defect in the mechanisms controlling the skin biocene including the natural antimicrobial peptides and nitric oxide. Most environmental factors influencing pityrosporoses indeed affect the natural human defenses against certain microorganisms. We frame as a hypothesis that the primary defect in some Malassezia-driven disorders resides in the corneocytes and their precursor keratinocytes