bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epidermal thickness measured by light microscopy: a methodological study
Authors: Therkildsen Pia , Haedersdal Merete , Lock‐Andersen Jørgen , de Fine Olivarius Frederik , Poulsen Thomas , Wulf Hans Christian 
Published: October 2006

Background/aims: Epidermal thickness is frequently measured by light microscopy. The preservation and staining methods may alter the proportions of the specimens and thereby influence the measurements. The aim of the present study was to describe: 1) a standardized light microscopic method to quantify the thicknesses of the stratum corneum and the cellular epidermal layers, 2) the variations according to preparation and staining techniques, and 3) the observer variability. Methods: One hundred and sixty skin biopsies from 67 human volunteers were included. The cellular epidermis and the stratum corneum were estimated in sections preserved by freezing and subsequent preparation with cryostat or formalin‐paraffin techniques. The slides were stained with haematoxylin‐eosin or er‐ythrocin, and thicknesses of the stratum corneum and the cellular epidermis were measured by a calibrated ruler and an ocular grid, respectively.Results: The formalin fixation gave slightly higher values for the cellular epidermis than the cryostat technique. In comparison to erythrocin staining, haematoxylin‐eosin gave a significantly thinner stratum corneum. No significant inter‐ or intra‐observer variation was found for the thickness of the stratum corneum assessed twice by two experienced observers. However, the two observers differed slightly from each other on the thickness of the cellular epidermis.Conclusion: It is found that thickness measurements of the stratum corneum and the cellular epidermis are reliably performed on cryostatic cut sections stained with haematoxylin‐eosin.
In vivo assessment of n‐alkyl‐sulfate‐induced skin irritation by means of non‐invasive methods
Authors: Nardo A. Di , Conti A. , Martini M. , Seidenari S. 
Published: October 2006

Background/aims: Sodium lauryi sulfate (SLS) is the most frequently used model for studying in vivo irritation. It is also one of the most frequent surfactants in soap preparations and cosmetic emulsions. To investigate the irritant potential of sodium salts of n‐alkyl sulfates with different carbon chain length (n=8, 12, 14), we applied these substances on the volar forearm of 10 healthy human volunteers aged 24 to 35 years.Methods: To allow the equal solubilization of the surfactants, we used a 0.2% solution (w/v). A colorimeter to assess erythema, an evaporimeter to assess transepidermal water loss (TEWL) and a corneometer to evaluate skin hydration were employed to estimate the effects of the chemicals on the skin. Evaluations were performed at baseline, 24, 48 and 72 h.Results: TEWL had increased at 24 h: SLS showed the highest increase, followed by octyl and tetradecyl sulfate. Skin hydration was reduced for the three substances, and a slight increase in redness was noticed. TEWL and hydration values at different times of assessment enabled the ranking of n‐alkyl sulfates in the following order: lauryi sulfate, tetradecyl sulfate and octyl sulfate.Conclusions: We could not prove a direct correlation between barrier impairment, skin dehydration and surfactant‐induced inflammation, as evaluated by color measurements. This discrepancy suggests that the irritation potential of n‐alkyl sulfates at the dermal level differs from their action on skin barrier.
Comparison of the efficacy and safety of three different depilatory methods
Authors: Bjerring Peter , Egekvist Henrik , Blake Thomas 
Published: October 2006

Background/aims: Three methods of electrical energy‐based depilation were compared for safety and efficacy.Methods: Ten volunteers had one treatment with each device followed by weekly observations up to 9 weeks. The protocol used was basically that of the International Guild of Professional Electrologists, which is used to define “permanent” hair removal.Results: Radio frequency tweezers, direct current tweezers and needle based electrolysis all demonstrated statistically significant reductions in hair counts after 9 weeks of 60.3%, 65.8% and 55.9%, respectively. The differences between the treatments were not statistically significant. However, large differences in side effects and pain scores existed. Both tweezer type epilators induced pain rated at 13/100 on a visual analogue scale while the needle based depilator induced significant pain at 59/100. Furthermore, acute inflammation and late scarring was seen only following treatment with the electrolysis needle.Conclusion: The tweezer‐type epilators are as effective as needle‐based electrolysis but without the pain and side effects of the latter.
The face and neck: regional variation in skin barrier function and reactivity
Authors: Leroy T. , Geveaux C. , Crucq J. , Douven L. F. A. , Neste D. Van 
Published: October 2006

Background/aims: Although there are many reports of regional variations in skin response to various stimuli, only a few studies have been performed on the face. The forearm is the most often used test site while the face is a frequent and specific target of many topical agents (drugs and cosmetics) and cosmetic procedures. The aim of this study was to compare regional variations of cutaneous sensation and skin barrier function in the cheek, neck and forearm before and after application of different stimuli (physical and/or chemical).Methods: Physiological changes of the skin were measured by non‐invasive methods: TEWL (transepidermal water loss) and skin capacitance. Furthermore, clinical scoring and subjective sensations were reported. The anatomical sites evaluated were cheek, neck and volar forearm.Results: Great differences in clinical reactions, subjective sensations and skin barrier function in response to various stimuli have been observed between tested areas (cheek, neck and forearm). We observed a greater “sensitivity”, i.e., more severe clinical reactions and subjective sensations of the cheek and neck areas, in relation to chemical stimuli as compared to the forearm. After a mechanical stimulus, the forearm was the most sensitive site, but just for subjective sensations. Concerning skin barrier function, the cheeks exhibited the highest values of TEWL and the forearms the lowest.Conclusion: In view of the high “sensitivity” of the cheek as compared to the forearm, it will be more cautious to assess the safety of facial cosmetics on the sites of intended use.
Electrical impedance and other physical parameters as related to lipid content of human stratum corneum
Authors: Nicander I. , Norlen L. , Brockstedt U. , Rozell B. Lundh , Forslind B. , Ollmar S. 
Published: October 2006

Background/aims: In previous studies we have shown that variations in the properties of the stratum corneum are reflected by alterations in electrical impedance. The aim of this study was to explore the ability of the electrical impedance technique to detect changes in the lipid content of the stratum corneum, and to compare It with the other non‐invasive methods, measurement of transepidermal water loss and of skin moisture.Methods: Twenty‐two healthy test subjects were recruited. Transepidermal water loss was measured at standard sites on the forearms and wrists, followed by skin moisture estimation by electrical capacitance, and finally by the recording of electrical impedance spectra in the frequency range 1 kHz to 1 MHz. Readings by all three methods were taken before the start of each series of test procedures, as well as after cyclohexane swabbing, a skin stripping procedure and lipid extraction, and also during the recovery process. A mixture of hexane:isopro‐panol was used for lipid extraction of the skin, and the extracts were evaluated using HPLC/LSD and GC/MS/FID analysis. Biopsy samples for light and electron microscopy were obtained after lipid extraction.Results: Electrical impedance results showed greater changes after lipid extraction than either transepidermal water loss or skin moisture content. Baseline values varied from the cubital fossa to the wrist, both for the non‐invasive methods and for lipid composition.Conclusions: The electrial impedance is dependent on the lipid content of the stratum corneum, as studied by lipid extraction experiments.
Reproducibility of laser Doppler imager flux measurements within ischemic or venous ulcers and adjacent skin
Authors: Gschwandtner Michael E. , Ambrózy Ewald , Böhler Kornelia , Fasching Sonja , Gaggl Uwe , Schneider Barbara , Ehringer Herbert 
Published: October 2006

Background/aims: The laser Doppler imager (LDI) is a device that maps the local distribution of the laser Doppler flux of tissues. To facilitate the interpretation of LDI measurements, we investigated their reproducibility.Methods: We measured 10 arterial ulcers, 10 venous ulcers and their adjacent skin by the use of a LDI. The means were calculated of individual coefficients of variation ± standard error of mean (meanCV±SEM) of measurements on the same day, on 5 different days and at specific time points (0, 30, 60, 90 and 120 min) during the application of PGE, on 2 different days.Results: The meanCV±SEM of measurements on the same day were 9.3±0.9% (ulcer), 9.8±0.9% (skin), and on 5 different days they were 21.9±1.9% (ulcer) and 28.6±2.4% (skin). Ulcer measurements on 5 different days were significantly more reproducible than skin measurements, if differences were calculated for all 20 patients or for the 10 patients with venous ulcers separately (P<0.05). During the application of PGE, for 120 min, meanCV±SEM ranged from 19.2±4.0% to 26.9±5.0% (ulcer) and from 20.5±4.1% to 29.5+3.9% (skin). CV of skin measurements of all 20 patients at 0 min were significantly lower than those after 120 min of PGE1‐application (P<0.05).Conclusion: Our results show an excellent reproducibility of LDI measurements on a single day. The reproducibility of measurements on 5 different days or during the application of PGE1 over a period of 120 min was poorer. Because of the poorer reproducibility, more patients are needed to study long‐term or drug effects.
Mechanical properties of human skin equivalents submitted to cyclic tensile forces
Authors: Lafrance Hugues , Yahia L'Hocine , Germain Lucie , Auger François A. 
Published: October 2006

Background/aims: As human skin equivalents (SE) represent an important breakthrough for clinical grafts and experimental tools, the various methods for mechanical and functional analyses are also gaining importance in the optimization process. SE characteristics have already been studied through indentation‐strength and strain‐energy methods. Since repeated tensile loading is a common reality of skin, we present in this paper the evolution of the indentation readings method for SE, including its dermal equivalent (DE) and collagen gel (CG), during cyclic tests.Methods: Briefly, the in vitro production of the disk‐shaped (25.4‐mm‐diameter) SE is based on the culture, under submerged conditions, of keratinocytes seeded on our anchorage‐based DE, a human type I+III CG supplemented with elastin and GAGs. All specimens were submitted to quasi‐static ramp‐deflection cycles induced by means of an actuated hemispherical head (12.7‐mm‐diameter). We studied the effects of repeated loading through monitoring of the indentation load (P) versus the deflection (Δ) and the relaxation of P over 1000 s.Results: With the help of the P‐Δ indentation curves, we determined characteristics for typical CG, DE and SE. Following the respective loading history for each specimen, we demonstrated that the loading and unloading branches, the residual and the upper P, and the hysteresis shaped by the loading‐unloading loop were consistent characteristics in the functional analysis of tissue engineered dermis and epidermis.Conclusion: The P‐Δ indentation curves obtained from a loading history give valuable characteristics that allow accurate description of the mechanical behavior of tissue engineered skins during their optimization process for transplantation or experimental purposes.
Open application assay in investigation of subclinical irritant dermatitis induced by sodium lauryl sulfate (SLS) in man: advantage of squamometry
Authors: Charbonnier Veranne , Morrison Boyce M. , Paye Marc , Maibach Howard I. 
Published: October 2006

Background/aims: After a single occlusive application (24 h patch test), SLS can cause irritation, dryness, and tightness. In typical use, clinical surfactant exposure is usually brief, of open application, and cumulative. The open application model becomes relevant when phenomena, such as dryness and subclinical, i.e., non‐visible, irritation are induced.Methods: Exaggerated hand wash was performed in a total of 21 healthy individuals. Signs of skin irritation were scored, and skin reactions were measured using various bioengineering techniques.Results: These studies demonstrate that an exaggerated hand wash model permits exploration of sub‐clinical irritation.Conclusions: Squamometry proved to be a sensitive, complementary method to detect surfactant‐induced, sub‐clinical skin alterations.
Transepidermal water loss kinetic modeling approach for the parameterization of skin water dynamics
Authors: Rodrigues Luis , Pinto Pedro , Galego Nuno , Da Silva Pedro A. , Pereira Luis Marcelo 
Published: October 2006

Background/aims: The evaluation of transepidermal water loss (TEWL) is one of the methods most frequently used in studies involving skin water dynamics. However, TEWL does not provide a direct measurement of epidermal barrier function, being rather a surrogate effect of it. In particular, when external stimuli change cutaneous water balance, these stimuli must be taken into account in order to achieve a rigorous interpretation of the results. Since TEWL is primarily attributed to the water flux from the deepest layers of the skin, through the epidermis, and towards the external environment, this whole process is reasonably compliant with Fick's first law of diffusion. Within this perspective, the aim of this work was to develop a two compartment mathematical model capable of quantitatively describing cutaneous water mass balance over time and thus to provide practical and objective comparable parameters that are particularly useful for studies critically depending on a precise evaluation of TEWL.Methods: The theoretical basis for the proposed model was tested with data collected from different protocols that use TEWL as the main indicator of induced cutaneous alterations. Those alterations involved either external inputs or intrinsic changes on the cutaneous pathway capable of changing the whole water balance across the skin, either altering epidermal cohesion or promoting a significant influx of external water.Results: Both the evaporation and the hydration equilibrium processes, merged within the TEWL curve profiles, were thoroughly described in a quantitative fashion using a mathematical model. Direct parameters were calculated, such as kinetic rate constants (khydr and kevap) and half‐life times (t1/2 hydr and t1/2 evap) chosen to describe the hydration and evaporation processes. Secondary parameters, such as time to reach the maximum and an area under the curve derived parameter, the dynamic water mass (DWM), were also calculated, providing additional data particularly useful for comparisons.Conclusion: Modelling TEWL experimental data in a compartmental analysis framework provides valuable parameterized information for characterising and comparing results. Numerical parameters derived on solid theoretical assumptions are reliable indicators for many situations, as long as those assumptions are not violated. The proposed bicompartmental model may also be suitable for other cutaneous water balance related variables, such as capacitance or conductance, although eventually based on distinct model assumptions. In any case, this modelling conceptualisation seems to render valuable insights into the kinetic description of the main processes involved in the net evaporation and water distribution within the complex human skin hydration process.
Optical coherence tomography in dermatology
Authors: Pagnoni A. , Knuettel A. , Welker P. , Rist M. , Stoudemayer T. , Kolbe L. , Sadiq I. , Kligman A. M. 
Published: October 2006

Background/alms: Optical coherence tomography is a new in vivo imaging tool originally developed to investigate the eye. We undertook a preliminary investigation of experimental and clinical dermatological applications.Methods: We obtained optical coherence tomography images of ethnic groups, of cutaneous changes induced by exposure to water and dimethyl sulfoxide, of corticosteroid atrophy and of acne vulgaris.Results: Optical coherence tomography was able to visualize specific structural changes in stratum corneum and viable epidermis in these diverse conditions.Conclusions: The high lateral and axial resolution of 4 urn and 7 μm, respectively, and the image quality of this prototype make optical coherence tomography a promising instrument for clinical and investigative dermatology.
Minimal erythema dose in UV‐shielded and UV‐exposed skin predicted by skin reflectance measured pigmentation
Authors: Lock‐Andersen Jôrgen , de Fine Olivarius Frederik , Haedersdal Merete , Poulsen Thomas , Wulf Hans Christian 
Published: October 2006

Aims: To investigate the relationships between epidermal thickness, age, skin pigmentation and UV sensitivity in sun‐exposed skin and skin not exposed to the sun in healthy people without skin cancer or skin diseases.Methods: Phototesting with a xenon arc solar simulator was performed in 137 healthy Caucasians in buttock skin un‐exposed to UV (27 children, 34 young adults and 32 older adults) and in skin of the back exposed to UV (44 young adults). The pigmentation of the phototest sites was measured objectively by a skin reflectance spectrometer before phototesting. Thickness of the stratum corneum and the cellular epidermis were measured in skin biopsies from the phototest sites. All measurements were performed in the winter and spring months.Results: Stratum corneum and cellular epidermis were thinner at the back than at the buttocks (P<0.01). Thickness of the stratum corneum at the back or the buttocks was not related to the degree of skin pigmentation (P=0.62 and P=0.20, respectively). Thickness of the stratum corneum at the buttocks was unaffected by gender (P=0.42) and age (P=0.83) whereas cellular epidermis decreased with age (P<0.01) and was thinner in females than in males (P<0.01). In spite of the higher pigmentation at the back than at the buttocks, the minimal erythema dose (MED) was lower at the back than at the buttocks (x=2.7 and x=2.2 SED's, respectively; P=0.04). Given the same degree of skin pigmentation, there was no difference in the MED in buttock skin in children, young adults and older adults un‐exposed to UV (P= 0.61). Prediction of the MED in un‐exposed buttock skin and in exposed skin of the back by a theoretical model based on an exponential function of the measured skin pigmentation was found to provide good estimates of the MED determined by phototest.Conclusion: Skin pigmentation at un‐exposed buttock skin can reliably predict the constitutive UV sensitivity in healthy Caucasian children and adults and is recommended in surveys where phototesting cannot be performed.
Comparative study of five instruments measuring stratum corneum hydration (Corneometer CM 820 and CM 825, Skicon 200, Nova DPM 9003, DermaLab). Part II. In vivo
Authors: Fluhr Joachim W. , Gloor Max , Lazzerini Sabrina , Kleesz Peter , Grieshaber Romano , Berardesca Enzo 
Published: October 2006

Background/aims: The hydration state of stratum corneum can be measured with different instruments. In the present study, five instruments were compared under different experimental in vivo conditions: Corneometer CM 820 and CM 825 (both capacitance based), Skicon 200 (conductance), Nova DPM (impedance based capacitance) and DermaLab (capacitance).Methods: Seven anatomical sites were tested, a sorption‐de‐sorption test (SDT) and a moisture accumulation test (MAT) were performed. Different hydration states were created on the volar forearms by occluded application of an oil‐in‐water (o/w) emulsion, glycerol and urea containing oil‐in‐water (o/w) emulsion, an untreated control site and a site after lipid extraction with acetone. Measurements were performed 15 min after removal of occlusion.Results: The coefficient of variation for CM 820 ranged between 9.3% and 23.7%; for CM 825 between 14.9% and 36.8%; for Skicon 200 between 53.0% and 167.3%; for Nova DPM between 36.4% and 95.8%; for DermaLab between 23.6% and 45.6%. All devices showed a highly significant correlation (P<0.0001) with a high Spearman coefficient r ranging between 0.7928 and 0.9358.Conclusions: CM 820 and CM 825 seem to differentiate more precisely than Nova DPM, Skicon 200 and DermaLab in dry conditions according to previous findings, i.e., that conductance measurements might be more sensitive for hydrated skin and capacitance measurements might be more sensitive for dry skin conditions. The CM 825, the Skicon 200 and the Nova DPM are suitable for dynamic measurements of hydration parameters of the stratum corneum.
Comparison of cheek and forehead regions by bioengineering methods in women with different self‐reported “cosmetic skin types”
Authors: Fur Isabelle Le , Lopez Sabine , Morizot Frédérique , Guinot Christiane , Tschachler Erwin 
Published: October 2006

Background/aims: Understanding structural and functional differences between facial areas is necessary for the formulation of cosmetics and dermatological preparations well tailored to the skin's biophysical characteristics. The objective of the present study was to compare biophysical parameters on malar and frontal facial areas of healthy women classified according to self‐reported cosmetic skin types.Methods: The study population comprised 253 women aged from 20 to 50 years who did not display any signs of dermatological disease. Women declared spontaneously their cosmetic skin type. Skin capacitance, sebum casual level, skin temperature, transepidermal water loss (TEWL), skin colour and relief were assessed on cheeks and forehead in a controlled environment.Results: All biophysical parameters showed statistically significant differences between the two zones. Mean a* chromametric values and TEWL values were significantly higher on cheeks. In contrast, mean b* chromametric values and sebum casual levels showed the highest values on the forehead. Moreover, skin capacitance, temperature, roughness and L.* chromametric value showed minor, while statistically significant, differences between the two zones. With marginal exceptions, the differences between the facial zones for each biophysical parameter remained statistically significant, irrespective of self‐reported skin type.Conclusion: Biophysical parameter mean values differ between frontal and malar zones regardless of self‐reported skin type. Except for the elevated sebum casual levels in “greasy” and “combined” skin, no single or combined biophysical characteristics could be linked to any of the self‐reported skin types. Furthermore our data confirm that in contrast to the common belief that “dry” skin is associated with reduced sebum production, sebum levels in women declaring to have “dry” skin and those declaring to have “normal” skin were not found to be different.