Charles Zerweck

Comparative metrology of the evaporimeter and the DermaLab® TEWL probe

Transepidermal water loss (TEWL) measurements are one of the most frequently utilized of the noninvasive bioengineering techniques. Recently, Cortex Technology (Hadsund, Denmark) introduced the DermaLab® system, which can be equipped with a TEWL probe. It is based on the vapor pressure gradient estimation method of Nilsson and, thus, is quite similar to the Servo Med evaporimeter. In this paper, we compare these two commercial instruments under identical experimental conditions using both in vitro studies with physical standards as well as in vivo studies employing human volunteers.

Documentation of impaired epidermal barrier in mild and moderate diaper dermatitis in vivo using noninvasive methods.

Abstract:  The presence of irritants from feces and urine with the concurrent mechanical friction and occlusion creates an environment in the diapered area that renders the skin prone to diaper dermatitis. Besides being a source of discomfort to the infant, these skin irritations pose a risk of secondary infections. In this study, we used noninvasive in vivo techniques to define measurable parameters that correlate with diaper dermatitis pathophysiology. In 35 infants (16 with mild or moderate and 19 without diaper dermatitis) we compared skin of diapered areas afflicted with diaper dermatitis to lesion‐free diapered sites and to skin outside the diapered area (thigh). Our findings show significantly elevated cutaneous erythema, pH, and hydration, with significantly compromised water barrier function in involved areas compared to nonlesional sites both within and outside the diapered area. Furthermore, skin pH in nonlesional diapered skin for the diaper dermatitis cohort was significantly higher compared to the nondiapered sites. These observations are consistent with the current understanding of pathological skin changes in diaper dermatitis. In this study, we demonstrate that noninvasive methods can document relevant parameters to diaper dermatitis in vivo.

Computerized evaporimetry using the DermaLab® TEWL probe

TEWL measurements are one of the most frequently utilized of the non‐invasive bioengineering techniques. We wanted to enhance the reproducibility and sensitivity of this method by employing computerized evaporimetry.

A Pilot Study of Noninvasive Methods to Assess Healed Acute and Chronic Wounds

Background. A variety of instruments are available that can objectively assess physical parameters of the skin such as strength, firmness, elasticity, hydration, and color, often undetected by clinical assessment. Objective. To assess the physical properties of healed acute and chronic wounds using several noninvasive instruments. Methods. Four patients with healed acute wounds and four patients with healed chronic wounds were studied using ballistometric, impedance, levarometric, and spectrophotometric measurements. Results. In general, scars were harder, less elastic, dryer, and more erythematous than control skin. These differences were more pronounced in healed chronic wounds. Conclusion. A scar from an acute surgical wound becomes softer, more elastic, dryer, less erythematous, and less pigmented as it ages. In contrast, chronic wound scars become harder as they age. These different properties of healed acute wounds and healed chronic wounds may be a result of the different healing processes in each wound type.

A randomized and controlled comparison of gentleness of 2 medical adhesive tapes in healthy human subjects.

PURPOSE To compare gentleness of a silicone tape to a paper tape and to an untreated control. DESIGN Controlled, randomized, grader-blinded cohort trial. SUBJECTS AND SETTING The sample group comprised 28 healthy volunteers aged 55 years and older (median age = 63 years) with a Fitzpatrick Skin Type of I, II, or III. All volunteers were recruited from the greater Philadelphia area and the study was conducted at a dermatological research facility specializing in noninvasive instrumental measurements. METHODS Tapes were applied and removed daily (excluding weekends) to 2 of 3 sites on the left and right volar forearms over an 11-day period. The center site on each forearm was left untreated and tapes were randomized to the proximal and distal sites. The primary assessment was transepidermal water loss (TEWL); secondary assessments included erythema/edema, denudation/skin-stripping, and subject self-evaluations. Study personnel conducting the primary and secondary assessments were not involved with treatments to maintain the blinded nature of the study. The identity of the 2 tapes was not revealed to the subjects until after conclusion of the study. RESULTS On day 11 the mean TEWL value for the paper tape was significantly higher than that for both the untreated control and silicone tape (P < .001). End-of-study mean TEWL values were 2.65 ± 0.68 g/mh for the silicone tape, 6.85 ± 4.97 g/mh for the paper tape, and 3.73 ± 1.19 g/mh for the untreated control. At all assessments, the silicone tape exhibited net changes from baseline that were significantly less than the paper tape (P < .05 day 1, P < .001 days 4, 7, and 11) and similar for the untreated control. Only at days 4 (P < .01) and 11 (P < .001) was the paper tape significantly higher than that for the untreated control. Throughout the study, both tapes exhibited mean TEWL values within the range of normal intact forearm skin, indicating that both tapes were gentle. No differences in erythema/edema scores occurred but the silicone tape resulted in lower denudation/skin-stripping scores than the paper tape at days 4 to 11 (P < .0001). Self-assessment of pain at removal was low for both tapes but significantly lower for the silicone tape (days 1-7, P = .02; day 11, P = .009). Forty-four percent of participants expressed a preference for the silicone tape as compared to the paper tape (19%), with 37% stating no preference. CONCLUSIONS Based on TEWL assessment of disruption of the stratum corneum water barrier, the silicone tape proved gentler to the skin than the paper tape. After 9 applications and removals over 11 days of study, the silicone tape was similar to the untreated control, whereas the paper tape exhibited significantly higher mean TEWL values than both the untreated control and the silicone tape. Expert grader assessments corroborate these findings. These data indicate that the silicone tape may provide additional gentleness when it is clinically needed.

Dry skin in the winter is related to the ceramide profile in the stratum corneum and can be improved by treatment with a Eucalyptus extract

Dry skin in the winter has been reported to involve scaling, defects in water holding and barrier functions, and decreased ceramide (CER) levels in the stratum corneum (SC). We previously reported that a Eucalyptus extract promotes CER synthesis in cultured keratinocytes and accelerates the recovery of hydration in a barrier‐disrupted model of human skin.

Randomized comparison of a silicone tape and a paper tape for gentleness in healthy children.

PURPOSE: To compare the relative gentleness of a silicone tape to a paper tape in healthy infants and children. DESIGN: A randomized, grader-blinded, comparative study. SUBJECTS AND SETTING: The sample group comprised 24 healthy infants and children 9.1 to 46.7 months of age (mean ± SEM, 34.0 ± 2.21). The study was conducted at a dermatological research facility (cyberDERM, Inc) located in Broomall, Pennsylvania. All volunteers were recruited from the surrounding community. METHODS: Tapes measuring 1 × 1.5 inches were randomly applied to the left and right intrascapular regions of the upper back. Tapes were removed in a standardized fashion after 24 hours. The primary study outcome, gentleness, was based on visual assessments of skin damage, discomfort, and quantification of keratin removal. Four-point scales were used to assess skin damage, and a 10-point Faces, Legs, Activity, Cry, and Consolability instrument was used to assess discomfort. Secondary assessments included hair removal, tape edge-lift assessments, and parent preference for either tape. RESULTS: There was a significantly lower mean ± SEM erythema response for the silicone tape (0.93 ± 0.14 vs 1.35 ± 0.11, P = .0129) than for the paper tape. No measurable epidermal stripping occurred with the silicone tape compared to a mean ± SEM response of 0.29 ± 0.11 for the paper tape (P = .0039). Discomfort was significantly lower (P = .0002) for the silicone tape as compared to the paper tape (Faces, Legs, Activity, Cry, and Consolability score mean difference from baseline 0.5 vs 3.3, P = .0002). Keratin removal was significantly less with the silicone as compared to paper tape (8.7 ± 0.5 &mgr;g/mL vs 15.2 ± 1.3 &mgr;g/mL, P < .0001). Few hairs were removed with either tape. There was significantly less (P < .0001) edge-lift with the paper tape than the silicone tape; no statistically significant differences in parent preferences for silicone versus paper tapes were measured (P = .3359). CONCLUSIONS: Gentleness assessments favored the silicone tape compared to a paper tape and warrant further clinical investigation in the neonatal intensive care unit.

Suction Chamber Method for Measurement of Skin Mechanics: The DermaLab

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Dye exclusion as a means to measure wetness protection of human skin

Background/purpose: Excessive skin hydration from occlusive coverings such as absorbent articles, bandages, etc. has been known to compromise the skins barrier properties. Damage to the stratum corneum occurs from prolonged exposure to wetness and limited product breathability, which reduces evaporation. Protection from wetness may be imparted by barrier materials, such as lotions and ointments on the skin. Barrier materials are traditionally applied by hand from bulk containers (bottle or tube). In recent years, diapers have been made that contain barrier ointments designed to transfer to the skin during wear. The purpose of this research was to develop a reliable in vivo method for evaluating skin wetness protection when using personal products.

Shadow analysis via the C+K Visioline: A technical note

This research investigated the ability of shadow analysis (via the Courage + Khazaka Visioline and Image Pro Premiere 9.0 software) to accurately assess the differences in skin topography associated with photo aging.