Showing papers in "Skin Research and Technology in 2007"

Porcine ear skin: an in vitro model for human skin

Abstract: Background/purpose: Porcine ear skin is used in studies of percutaneous penetration as a substitute for human skin. The structure of this tissue, including hair follicles, was studied qualitatively and quantitatively in comparison with human skin. Methods: Sections of shock-frozen biopsies, biopsies embedded in paraffin and cyanoacrylate skin surface biopsies were investigated using microscopy. The thickness of the different skin layers and the follicular characteristics were determined. Results: The thickness of the stratum corneum was 17–28 μm, whereas the viable epidermis was 60–85 μm thick. On 1 cm2, 11–25 hairs were detected, showing a diameter of 58–97 μm and a maximal extension depth of 0.96–1.38 mm into the skin. The orifices of the porcine infundibula showed a diameter of approximately 200 μm. Conclusions: The results obtained are similar to those of human skin, indicating the suitability of this porcine tissue as a model for human skin.

Unsupervised border detection in dermoscopy images

Abstract: Malignant melanoma has consistently been one of the most rapidly increasing cancers of all, with an estimated incidence of 59,580 and an estimated total of 7770 deaths in the United States in 2005 (1). Early diagnosis is particularly important as melanoma can be cured with a simple excision if detected early. This study uses contact dermoscopy images. Contact dermoscopy is a non-invasive imaging technique using a glass plate and alcohol, gel or oil immersion, which renders the skin translucent, thus allowing a better visualization of the surface and subsurface structures. A systematic review covering Medline entries from 1983 to 1997 revealed that dermoscopy had 10–27% higher sensitivity (2). In a more recent meta-analysis (3), dermoscopy experts achieved a 49% increase in diagnostic accuracy when compared with clinical assessment, with results confirmed by other studies (4). However, it has been demonstrated that dermoscopy may actually lower the diagnostic accuracy in the hands of inexperienced dermatologists (5). Therefore, due to the lack of reproducibility and subjectivity of human interpretation, the development of computerized techniques is of utmost importance (6). The first step in the computerized analysis of skin lesion images is the detection of the lesion borders. The importance of the border detection for the analysis is twofold. First, the border structure provides important information for accurate diagnosis. Many clinical features such as asymmetry, border irregularity, and abrupt border cutoff are calculated from the border. Second, the extraction of other important clinical features such as atypical pigment networks, globules, and blue-white areas critically depends on the accuracy of the border detection. Automated border detection in dermoscopy images is a challenging task due to several reasons: (a) low contrast between the lesion and the surrounding skin, (b) irregular and fuzzy lesion borders, (c) artifacts such as skin texture, air bubbles, and hairs, and (d) variegated coloring inside the lesion. Several methods have been developed for border detection in skin lesion images, with many previous efforts dealing with clinical images (7). Here, we review the border detection methods applied to dermoscopy images. Gao et al. (8) have proposed a method based on a stabilized inverse diffusion equation, a form of non-linear diffusion. Schmid (7) proposed a technique based on color clustering. First, a 2D histogram is calculated from the first two principal components of the CIE L*u*v* color space. Then, the histogram is smoothed and initial cluster centers are determined from the peaks using a perceptron classifier. Finally, the lesion image is segmented using a modified version of the fuzzy c-means clustering algorithm. Donadey et al. (9) presented a supervised method based on intensity radial profiles calculated from the I (intensity) component of the HSI space. Haeghen et al. (10) proposed a very simple supervised method that exploits the CIE L*a*b* color space. In this method, the background skin color is determined from a rough outer border drawn by the user. This initial border is then shrunk as long as the local color is similar to the background skin color. In this paper, we present an unsupervised approach to border detection in dermoscopy images based on a modified version of the JSEG algorithm (11). We adapted the JSEG algorithm to this problem due to its flexibility and good performance in a variety of domains such as natural scenery (11), colonoscopy images (12), tongue images (13), etc.

Sub-epidermal imaging using polarized light spectroscopy for assessment of skin microcirculation

Abstract: Background/aims: Many clinical conditions that affect the microcirculation of the skin are still diagnosed and followed up by observational methods alone in spite of the fact that non-invasive, more user-independent and objective methods are available today. Limited portability, high cost, lack of robustness and non-specificity of findings are among the factors that have hampered the implementation of these methods in a clinical setting. The aim of this study is to present and evaluate a new, portable and easy-to-use imaging technology for investigation of the red blood cell (RBC) concentration in the skin microvasculature based on the method of polarization light spectroscopy using modified standard digital camera technology. Methods: The use of orthogonal linear polarization filters over both the flash source and the detector array removes the polarization-retaining light reflected from the epidermal layer. Only the depolarized light backscattered from the papillary dermal matrix reaches the detector array. By separating the RGB color planes of an image acquired in this manner and applying a dedicated image processing algorithm, spectroscopic information about the chromophores in the dermal tissue can be attained. If the algorithm is based on a differential principle in which the normalized differences between the individual values of the red and green color plane are calculated, tissue components with similar spectral signature in both planes are suppressed, while components with different spectral signatures such as RBCs are enhanced. Results: In vitro fluid models compare well with theory and computer simulations in describing a linear relationship between the imager output signal termed the tissue viability index (TiViindex) and RBC concentration in the physiological range of 0–4% RBC fraction of tissue volume (cc=0.997, n=20). The influence of oxygen saturation on the calculated RBC concentration is limited to within −3.9% for values within the physiological range (70–100% oxygen saturation). Monte Carlo simulations provide information about the sampling depth (about 0.5 mm on the average) of the imaging system. In vivo system evaluation based on iontophoresis of acetylcholine displays a heterogeneous pattern of vasodilatation appearing inside the electrode area after about 10 min. Topical application of methyl nicotinate and clobetasol propionate further demonstrates the capacity to document the extent and intensity of both an increase (erythema) and a decrease (blanching) in the skin RBC concentration without movement artifact and with compensation for irregularity in pigmentation. Conclusions: Polarization light spectroscopy imaging for assessment of RBC concentration in the skin microvasculature is a robust and accessible technique for the clinical setting. Additionally, the technique has pre-clinical research applications for investigation of the spatial and temporal aspects of skin erythema and blanching as well as a potential role in drug development, skin care product development and skin toxicological assessment.

Efficient and simple quantification of stratum corneum proteins on tape strippings by infrared densitometry.

Abstract: Background: The analysis of stratum corneum (SC) components is a widely accepted method to determine ‘skin health’ status or to follow the effects of topical treatments. These analytes are normally corrected to the amount of SC removed which can be determined gravimetrically or by extraction of SC proteins and their subsequent analysis. Unfortunately, this is a time consuming procedure and usually requires a laboratory. As a result there is a need for equipment that can be used in a clinical setting. Equally, a concurrent determination of total SC protein content and enzyme activity or any other analyte on the same tape stripping is difficult and also time consuming. Therefore a compact infrared densitometer was developed allowing a convenient and user friendly indirect measurement of SC protein content on tape strippings by optical absorption. As this is a non-destructive technique, the tape strippings can subsequently be utilized for any other bioassay. Methods: Using tape strippings from human subjects the SC optical absorption was determined densitometrically and after extraction of the tape strippings, their protein content was measured. A comparison between SC optical absorption and protein content was made between samples from different body sites, differing hydration and pH levels, different age groups and between the genders. Results: The progression of absorption and protein curves was similar irrespective of tape strip number. The overall coefficient of determination (n=238) between absorption and protein content of forearm measurements was R2=0.852 and the corresponding overall linear regression 0.623x+2.703. Although the data distribution in the different subject groups varied, the regression was always quite similar and independent of gender, age, skin hydration rate, skin pH and varying skin areas. The correlations reached were statistically significant. Conclusion: Infrared densitometry is an easy to use and non-destructive technique for the convenient measurement of the optical absorption of SC tape strippings which was shown to be linearly proportional to their protein content. Thus the corresponding SC densitometric-protein content calibration curves can be used for a fast indirect protein evaluation of tape strippings. As this is a non-destructive method, the unmodified tapes can be used for further investigations.

Indentometric analysis of in vivo skin and comparison with artificial skin models.

Abstract: Background/purpose: The mechanical properties of the skin have been previously analyzed by a number of different techniques including torsional analysis, cutometery, gas-bearing electrodynamometry, etc. The objective of this work is to present quantitative analysis of skin rheology by a technique termed indentometry. Methods: The instrument used was a texture analyzer, which is a mechanical tensiometer simulating the process of touch. The experiments were carried out on human subjects as well as on artificial skin models. They included indentometry tests performed by using spherical probes with various geometrical dimensions as well as stress relaxation and creep experiments. The experimental data were interpreted by using the Hertz theory of contact mechanics and by calculation of fundamental parameters such as the modulus of elasticity. Results: The calculated Young's modulae for skin models ranged from 5.5 × 104 to 17.7 × 104 N/m2, while the corresponding values for forearm and facial skin of ten panelists were found to be in the range of 0.7 × 104 –3.3 × 104 N/m2. In addition, stress relaxation and creep experiments were conducted, which permitted the assessment of the viscoelastic properties of skin. The results of these measurements were interpreted within the framework of the Kelvin–Voigt model of delayed elasticity leading to the calculation of viscosities and relaxation times. Indentomeric data, obtained by varying the diameter of the indentor and the indentation depth, are also discussed. Conclusion: The indentometric analysis for both in vivo skin and artificial skin models could be interpreted by using the Hertz theory of contact mechanics. The loading and unloading indentometric curves could be used to assess the viscoelasticity of the investigated materials while creep and stress relaxation processes were analyzed quantitatively by the Kelvin–Voigt model with one relaxation time.

Derivation and clinical application of special imaging by means of digital cameras and Image J freeware for quantification of erythema and pigmentation

Abstract: Background: Quantification of erythema and pigmentation is useful for analysis of skin tests and management of skin diseases. However, reflectance instruments for this purpose suffer from many technical and financial disadvantages. The aim of this study was to establish a method for evaluation of the amounts of haemoglobin and melanin using ordinary digital cameras and Image J freeware. Methods: Based on the theories on the absorbance of a multilayered skin model, the erythema index (EI) and melanin index (MI) images were derived by image processing from digital colour images of the skin, which were obtained with four kinds of digital cameras. The specificity of these indices and the linearity between index values and the amounts of haemoglobin and melanin were determined by using images of various concentrations of haemoglobin and melanin solutions. The accuracy of both types of index images was also examined by comparing the index values of UV-induced erythema and pigmentation of various intensities with those measured with a reflectance spectrophotometer. Results: The specificity of EI and MI images was good as little interference was noted with each other. The linearity between EI and haemoglobin concentration, as well as that between MI and melanin concentration was excellent. For UV-induced erythema and pigmentation, good linear correlation was confirmed between two types of EI obtained by the two methods, as well as between two types of MI. However, the index values derived from digital images depended on the camera used as well as on the circumstantial conditions, such as the distance from objects and illumination. Conclusion: EI and MI images are reliable and useful for quantifying erythema and pigmentation, if obtained under constant and consistent conditions. Apart from financial benefits, this method has many advantages and greater clinical utility in comparison with reflectance instruments.

Skin lesion classification using relative color features

Abstract: Malignant melanoma, with 59,940 new cases and 7110 deaths in the US estimated in 2007 (1), is easily cured if detected at an early stage. To the total of 59,940 new cases of melanoma, we can add an estimated 48,290 cases of melanoma in situ, a number growing at 15% per year in some countries (2). Unfortunately, the accuracy of physicians in diagnosing melanoma in the clinic is not high. In a recent study, general practitioners had a sensitivity and specificity for detection of melanoma of 62% and 63%, while dermatologists had a corresponding sensitivity and specificity of 80% and 60% (3). Dermoscopy examination can improve melanoma diagnostic accuracy (4). Although digital analysis of dermoscopic images gives more accurate results than digital analysis of clinical images (5), there may be a role for analysis of clinical lesions, as combining clinical and dermoscopic examinations has improved melanoma diagnostic accuracy (4). In this project, automatic classification of clinical images using relative color features was studied. Two types of benign lesion images Clark or dysplastic nevi and nevocellular nevi were used along with images of invasive and in situ malignant melanoma. This paper illustrates the use of computer imaging and pattern recognition in the detection of skin lesions. CVIPtools (6), a computer vision and image processing software, was used to extract the relative color features from the segmented skin lesion images. In order to maximize the possibility of achieving the goal, two feature spaces, lesion feature space and object feature space, were established with different combinations of the features. The feature spaces serve as two distinct data models to be analyzed with Partek (7), a statistical analysis software package, for analyzing and determining the best features through experiments. The statistical analysis model based on the best features was then found to better classify the various skin lesions with a successful classification rate of 86% for detecting malignant melanoma. This is comparable with the clinical accuracy of dermatologists.

Correlation between a Cutometer and quantitative evaluation using Moire topography in age-related skin elasticity.

Abstract: Background/purpose: As aging occurs, our skin gets more wrinkles, becomes drier and loses its elasticity. Validating the evaluation of skin elasticity is especially important, because it is not as visible as other signs of aging such as wrinkles. So it is needed that the method for measuring skin elasticity is able to reflect perception about the change of the skin state. Methods: Here, the correlation between age and the parameters given by a Cutometer® is identified and the main parameters that reflect the decreases in skin elasticity in terms of ages are presented. Also, Moire's system, an evaluation method to quantify the sensory value of viewing, is developed. A five-grade standard of Moire topographic photo scale on the face is used to evaluate the state of skin elasticity and lifting 20- to 61-year-old women. Based on this photo standard, scoring is performed using a five-grade system by three specialists to obtain the consensus score. The score is compared with the result of a Cutometer®. Results: Significant negative correlations between age and results of a Cutometer® (r=−0.687−0.725), Moire's topography scores (r=−938), were found. Some Cutometer® parameters and the decreases in skin elasticity in terms of ages were highly correlated (r=−0.687−0.725). The results from Moire system and flexibility as sensory evaluation also had a very high correlation with age (r=−0.765−0.932). Finally, we have shown the significance of the correlation between the result of a Cutometer® and the score of Moire topography (r=0.711). Conclusions: It is considered that Cutometer® parameters R7 and R2 are used as main parameters to assess skin elasticity and aging. And our studies using Moire topography on the face have confirmed that instrumental measurements reflect the decrease in skin elasticity, which is perceived visually.

Application of optical non-invasive methods in skin physiology: a comparison of laser scanning microscopy and optical coherent tomography with histological analysis.

Abstract: Background/purpose: Optical, non-invasive methods, such as fluorescence laser scanning microscopy (LSM) and optical coherent tomography (OCT), have become efficient tools for the characterization of the skin structure in vivo, as well as real-time investigation of distribution and penetration of topically applied substances. Methods: In the present paper, the results obtained with both non-invasive methods – OCT and LSM – were compared to conventional light microscopy of histological sections. Skin structure and the distribution of topically applied particulate and non-particulate substances on the skin surface and in the epidermis were analyzed. Results: None of the methods used are suitable for the realization of all diagnostic tasks, however, each method has advantages for particular applications. Fluorescence LSM is well suited for the investigation of the upper 150 μm of the skin as well as for the investigation of the kinetics of substances applied onto or into the epidermis. OCT can be applied for the investigation of vertical cross-sections of the skin up to a depth of 2 mm, albeit at lower resolution than achieved by LSM or conventional light microscopy. Conventional light microscopy of histological sections of biopsy specimens produces familiar high-resolution images of deeper tissue layers. However, the analysis of the kinetic processes is limited in this case. Conclusions: LSM- and OCT-measurements are efficient non-invasive tools for the characterization of morphological structures of the skin. On the one hand, the optical methods have a clear advantage in the case of kinetic measurements. On the other hand, histological investigations are characterized by a high information density and a high resolution, also in deep tissue layers. The selection of the best method for the analysis of the skin morphology depends on the target and the task of the investigation.

Study of skin-fabric interactions of relevance to decubitus: friction and contact-pressure measurements

Abstract: Background/purpose: Prolonged pressure as well as friction and shear forces at the skin–textile interface are decisive physical parameters in the development of decubitus. The present article describes the contact phenomena at the skin–textile interface and the development of a purpose-built textile friction analyser (TFA) for the tribological assessment of skin–fabric interactions, in connection with decubitus prevention. Methods: Interface pressure distributions were recorded in the pelvic and femoral regions between supine persons and a foam mattress. Fabrics made of various natural and synthetic yarns were investigated using the TFA. A vertical load of 7.7 kPa was applied to the swatches, simulating high interface pressures at the skin–fabric interface and clinical conditions of bedridden persons. Fabrics were rubbed in reciprocating motions against a validated skin-simulating material to determine static as well as dynamic friction coefficients (COFs). Results: Maximum contact pressures ranged from 5.2 to 7.7 kPa (39–58 mmHg) and exceeded the capillary closure pressure (32 mmHg) in all investigated bedding positions. For both COFs, a factor of 2.5 was found between the samples with the lowest and highest values. Our results were in a similar range to COFs found in measurements on human skin in vivo. The results showed that our test method can detect differences of 0.01 in friction coefficients. Conclusion: TFA measurements allow the objective and reliable study of the tribology of the skin–textile biointerface and will be used to develop medical textiles with improved performance and greater efficacy for decubitus prevention.

A relative color approach to color discrimination for malignant melanoma detection in dermoscopy images.

Abstract: Early detection of malignant melanoma can be lifesaving (1–3) and may be aided by digital image analysis (4–10). Certain colors are associated with melanoma in dermoscopy images, including blue and gray in veil structures, dark gray, blue and black in peppering associated with regression, white in scar-like regression, erythema associated with inflammation, brown in dots, globules and blotches as well as the pigment network, and black in dots (11, 12). Automatic detection of colors in clinical images (13–18) and dermoscopy images (5, 6, 19) using a number of techniques has been presented, but delineation of the range of benign vs. malignant coloring in digital dermoscopy images has not previously been attempted. In previous research, a data-driven relative color histogram analysis technique was examined for determining colors characteristic of melanomas in clinical images (16, 17). The use of relative color (13), in which the background color is subtracted from the image color, has been proposed as a technique to avoid color distortion in the imaging process as well as a method of accounting for variations in normal skin color. This research presents the relative color histogram technique that is applied to discrimination of benign and malignant colors in dermoscopy images. An overview of the color feature analysis algorithm used in the present study is presented in Fig. 1. Experiments presented here compare detection of clustered colors, as seen in the dermoscopy image lesion structures listed above, with detection of colors without regard to structure. Additional experiments are performed to evaluate the histogram analysis technique based on diagnostic accuracy achieved with: (1) different numbers of lesion images used as training data to identify melanoma colors and (2) different areas of the lesion selected for color analysis. Fig. 1 Overview of algorithm for color feature calculations and lesion discrimination. The remaining sections of this paper include: (1) the techniques used to calculate the percent melanoma color and color clustering ratio features, (2) experiments performed for melanoma and benign lesion discrimination, (3) experimental results, (4) discussion, and (5) conclusions from the study.

Combination of features from skin pattern and ABCD analysis for lesion classification.

Abstract: Background/Purpose: It is known that the standard features for lesion classification are ABCD features, that is, asymmetry, border irregularity, colour variegation and diameter of lesion. However, the observation that skin patterning tends to be disrupted by malignant but not by benign skin lesions suggests that measurements of skin pattern disruption on simply captured white light optical skin images could be a useful contribution to a diagnostic feature set. Previous work using both skin line direction and intensity for lesion classification was encouraging. But these features have not been combined with the ABCD features. This paper explores the possibility of combing features from skin pattern and ABCD analysis to enhance classification performance. Methods: The skin line direction and intensity were extracted from a local tensor matrix of skin pattern. Meanwhile, ABCD analysis was conducted to generate six features. They were asymmetry, border irregularity, colour (red, green and blue) variegations and diameter of lesion. The eight features of each case were combined using a principal component analysis (PCA) to produce two dominant features for lesion classification. Results: A larger set of images containing malignant melanoma (MM) and benign naevi were processed as above and the scatter plot in a two-dimensional dominant feature space showed excellent separation of benign and malignant lesions. An ROC (receiver operating characteristic) plot enclosed an area of 0.94. Conclusions: The classification results showed that the individual features have a limited discrimination capability and the combined features were promising to distinguish MM from benign lesion.

A new experimental method for measuring skin's natural tension.

Abstract: Purpose: The precise determination of skin's mechanical properties is still an open question. When performing an in vivo test, the piece of skin tested is not as well defined as it is in material testing. Moreover, the body zone and the body posture imply an initial stress on the skin. Consequently, a precise mechanical analysis needs a precise measurement of the natural skin tension. Methods: A new method and the relative device are presented. It is based on an extensiometry test. Skin is tested not only in traction but also in compression. The tested skin sample is well defined and protected from surrounding effects by follower tabs. The size and shape of the device have been optimised by a finite element modelisation. Results: The method was tested with elastomers pre-tensioned at different loads. It is shown that the initial tension can be retrieved with good precision. Tests were then performed in vivo on the forearm for different arm positions. It is shown that initial tension could be only clearly determined for the highest skin tension, although the skin presented very different traction behaviour with different arm positions. Conclusion: It is shown how body posture influences measurements. An innovative method for easily determining initial tension is presented. Nevertheless, further tests and device improvements are needed to apply this skin tension measurement for different body zones and body postures.

Use of the Reviscometer for measuring cosmetics-induced skin surface effects.

Abstract: Background/purpose: The Reviscometer® RVM600 that measures resonance running time (RRT) has been shown to be inversely related to the skin stiffness. However, very few publications describe the use of this instrument for testing the effect of cosmetic products. Methods: Slight xerotic skin condition was induced by using an alkaline soap for 1 week. Skin has then been rehydrated with a lotion or further dehydrated and dried with sodium lauryl sulfate (SLS). Skin condition at the different stages of the study was evaluated by visual assessment for dryness and redness and by non-invasive methods (Corneometer®, Cutometer®, Reviscometer®, Evaporimeter® and squamometry). Results: All methods showed highly significant changes after the slight drying phase with the soap usage. They illustrated skin repair after lotion treatment and further skin impairment after SLS application. Nevertheless, the Reviscometer® was able to better statistically discriminate between the treatments (water, lotion, SLS) than the Cutometer®. Measurement of the RRT along the transversal axis of the forearms was the most sensitive for differentiating between normal and dry skin and between the treatments on the basis of skin mechanical properties. Conclusion: The Reviscometer® RVM600 is a sensitive instrument able to detect slight skin surface effect of cosmetics. Combined with published literature on the interpretation of RRT measurements on polymeric gel or in different skin conditions (elderly skin and photoaged skin), the Reviscometer® looks to be a recommendable instrument to measure slight changes in SC stiffness/suppleness induced by cosmetic products.

A simple and non-invasive visualization for assessment of carbonylated protein in the stratum corneum

Abstract: Background/purpose: Stratum corneum (SC) is the interface of body and environment and is continuously exposed to oxidative stress, resulting in oxidative modification of proteins. Consequent carbonylated proteins (CPs) have so far been labeled with 2,4-dinitrophenyl (DNP) hydrazine and subsequently detected with anti-DNP antibody. We developed a simpler, non-invasive method to assess CP level in the SC and applied it to following research. Methods: SC was collected by adhesive tape stripping and its carbonyl groups were labeled with fluorescein-5-thiosemicarbazide (FTZ). The staining image was observed by fluorescence microscopy and the average fluorescence intensity of the SC extracted from the image was calculated as stratum corneum carbonylated protein (SCCP) level. Results: By reaction with FTZ, carbonyl groups in the SC could be detected easily. Relatively strong fluorescence was observed in exfoliating scales. Lipid removal from the SC in vitro or in vivo did not show any change in fluorescence intensity, suggesting that carbonyl groups were mainly derived from proteins, not from lipids. SCCP level was higher in the upper layer than the lower layer, and higher in the cheek (sun-exposed) than the inside of upper arm (unexposed), positively correlated with age especially in male cheek, positively correlated with transepidermal water loss, negatively correlated with water content, and showed a subtle correlation with sebum level. On the other hand, SC collected by cyanoacrylate resin and labeled with FTZ revealed strong fluorescence around the pores in the cheek and on the grooves in the upper arm, suggesting the role of sebum in the generation of SCCP. Conclusion: SCCP was assessed in a simple and non-invasive method, and suggested to be a novel indicator that reflects some aspect of skin condition.

Digital dermoscopy in clinical practise: a three-centre analysis.

Abstract: Background: Early detection of cutaneous melanoma is the most important step to improve prognosis. In recent years objective techniques have been developed to improve diagnostics of pigmented lesions superior to the naked eye. Digital dermoscopy offers several advantages such as independence from the investigator, format ready for teledermatology and image storage, and comparability. Setting: In a routine setting including three centres in Europe, i.e. Lugano and Locarno in Switzerland, and Dresden in Germany, the usefulness of digital dermoscopy in daily routine has been evaluated. Patients and methods: Digital dermoscopy was performed with the DB-MIPS© system in 1308 patients, and 3544 pigmented lesions were evaluated. A total of 466 pigmented lesions were surgically removed and classified by histopathology. Among those 52 melanomas and 299 dysplastic, naevi could be identified. DB-MIPS© system evaluated 35 variables of geometrics, colour, colour distribution and texture. Lesion identification is realized by clustering. Another important part of the analysis was to study the decision making, i.e. removal or follow-up of lesions. The tendency to follow-up was defined as the ratio of (number of suspicious lesions-removed lesions)/suspicious lesions. The interventism is defined as the ratio of the number of removed lesions to the number of suspicious lesions. Results: The DB-MIPS© system was robust and easy in handling in daily routine. The data analysis and digital imaging were realized in real time. Fifty-two melanomas could be identified including eight in situ melanomas and 33 T1a melanomas (thinner than 1 mm). Sensitivity of digital dermoscopy varied between 90% and 95% between the three centres. Specificity varied between 79.6% and 93.3%. The centres differed in the patient population, the mean diameter of pigmented lesions and decisions. Interventism varied between 36.3% and 76.0%, follow-up varied from 24% to 63%. Higher levels of clinician's false positive were associated with a higher percentage of interventism. Conclusions: Digital dermoscopy offers advantages for daily routine in detection of early melanoma. Sensitivity and specificity for early melanomas is high and thereby, the experienced dermatologist can be easily supported in daily routine of a pigment lesion clinic to improve diagnostics and hopefully prognosis in cutaneous melanoma.

Cytokines at different stratum corneum levels in normal and sodium lauryl sulphate-irritated skin

Abstract: BACKGROUND/PURPOSE: Cytokines play an important role in inflammatory and repair processes occurring in the skin. The objectives of this study were to determine the amounts of cytokines and protein isolated by tape stripping in the different layers of the stratum corneum (SC), and to compare normal skin with skin exposed in vivo to the irritant sodium lauryl sulphate (SLS). METHODS: In eight volunteers, we determined the amount of total and soluble protein and also interleukin-1alpha (IL-1alpha) in pooled tape strips obtained from the upper, intermediate and lower parts of the SC. Three different types of tape were compared (Diamond , D-squame or Sentega tape). In a separate study, 20 volunteers were repeatedly exposed to 0.1% SLS over a 3-week period. The amounts of IL-1alpha, IL-1RA and IL-8 in strips obtained from the three different SC levels of SLS-exposed skin were compared with an unexposed site. RESULTS: For normal skin, the amounts of soluble protein and IL-1alpha were similar for the three tapes. Diamond tape showed the highest yield of total protein. The total protein yield per strip decreased to lower SC levels, whereas soluble protein and IL-1alpha normalized by soluble protein did not change across the SC. After SLS induced skin irritation, IL-1alpha decreased and IL-1RA and IL-8 increased at increasing depth into the SC. CONCLUSIONS: Tape stripping is a suitable method to determine SC cytokine concentrations in human skin. With this technique, it is possible to study changes in cytokine concentrations at different SC layers after skin irritation

Simultaneous determination of the nonlinear-elastic properties of skin and subcutaneous tissue in unconfined compression tests.

Abstract: Background/aims: The compressive nonlinear-elastic properties of soft tissues are usually determined using unconfined compression tests. To determine the nonlinear-elastic behavior of skin and subcutaneous tissue using a conventional approach, the skin and subcutaneous tissue had to be separated before testing. Using such an approach, measurement errors may be increased as a consequence of the reduced specimen dimensions and cumulative experimental errors. In the present study, we propose a novel method to determine the nonlinear-elastic behaviors of the skin and the subcutaneous tissue simultaneously using specimens of skin/subcutaneous composites. Methods: The stress/strain curves of skin and subcutaneous tissues are derived from stress/strain curves of soft tissue specimens with different skin/subcutaneous height ratios. There is no need to separate the skin from the subcutaneous tissue in the tests, thereby improving the reliability and reducing measurement errors. In order to demonstrate the application of the proposed approach, unconfined compression tests with skin/subcutaneous tissues collected from the front paws of pigs were conducted. Results/Conclusion: Using the proposed approach, stress/strain relationships of the skin and the subcutaneous tissue were derived from data determined in eight unconfined compression tests. The obtained stress/strain curves were consistent with published experimental data. Compared with conventional methods, the proposed approach is not only more efficient but also more reliable.

A long‐term evaluation of erythema and pigmentation induced by ultraviolet radiations of different wavelengths

Abstract: Backgrounds/aims: Although multiple studies have been reported about the biological effects of ultraviolet (UV) radiations, the comparative and long-term reactions of human skin by several different UV-wavebands were not reported. The aim of this study was to investigate a time course of erythema and pigmentation induced by UVA 1, broad-band UVA (BBUVA), narrow-band UVB (NBUVB) and broad-band UVB (BBUVB). Methods: Ten volunteers participated in this study for 6 months. Four skin areas, from the back of each subject, were irradiated with two minimal erythema dose (MED) of four different UV wavelengths corresponding to UVA 1, BBUVA, NBUVB and BBUVB. Skin color changes were evaluated by visual scoring and values were converted into the L*a*b color system. Results: For both UVA 1 and BBUVA, erythema and pigmentation were most pronounced immediately and 1 h after exposure. Thereafter, erythema rapidly diminished but pigmentation persisted throughout the study. For both NBUVB and BBUVB, test areas reacted with erythema of maximum intensity at 1 and 2 days, respectively. A maximum tanning was reached at 3–6 days for NBUVB and 4–7 days for BBUVB, and the return toward the original color point was at 1 and 3 months, respectively. No significant difference was found in visual and colorimetric evaluation for the time course of skin color changes. Conclusion: Two MED of UVA produced far prolonged erythema and pigmentation than UVB. For UVA, UVA 1 and BBUVA showed similar intensity and time course of skin reaction. For UVB, erythema and pigmentation produced by NBUVB were milder in intensity and shorter in time course than those by BBUVB. These results would provide standard data on time courses and intensity of skin color changes by different UV wavelengths.

Non-invasive monitoring of oxidative skin stress by ultraweak photon emission measurement. II: biological validation on ultraviolet A-stressed skin.

Abstract: Background/purpose: Several physical or chemical environmental stressors generate reactive oxygen species, which trigger oxidation reactions of cells or tissues and thereby induce a correlated ultraweak photon emission (UPE) signal. The present study was designed to qualify and validate UPE measurement following ultraviolet (UV) excitation of porcine and human skin as an analytical method to assess the potency of topical antioxidants in vivo. Methods: UPE of porcine skin in vitro and human skin in vivo following excitation with UVA was recorded using sensitive photomultiplier systems. For validation purposes, the effects of variation of extrinsic and intrinsic parameters encompassing skin thickness, humidity, temperature, pH, and composition of the surrounding atmosphere were assessed. Signals were analyzed with regard to overall signal intensity and spectral distribution. In two clinical trials enrolling 20 volunteers each, the effects of topical antioxidant treatment on UVA-induced UPE were validated. Results: Different stressors encompassing exposition to ozone, UVA irradiation, or even cigarette smoke induced UPE of skin. Critical parameters affecting the quality and quantity of the UPE signal were the spectral composition of the exciting UV light, skin temperature, skin humidity, and the O2 concentration of the surrounding atmosphere. Generally, UVA-induced UPE decreased with increasing temperature, humidity, and O2 concentration. Skin pH had no significant effect on UPE with regard to signal quality and quantity over a pH range of 2.8‐8.2. In a clinical study UPE measurement following UVA excitation could precisely reflect a dose-dependent antioxidant effect of topically applied vitamin C and a-glucosylrutin. Conclusion: Our data indicate that UVA irradiation induces UPE especially in deeper (living) skin layers, where antioxidants must be active in order to interfere with accelerated skin ageing. Based on the clinical data, and with knowledge of modulating external variables, UPE measurement following UVexcitation can be qualif ied as ar eliable and valid method for the non-invasive measurement of antioxidant efficacy on the skin.

Non-invasive monitoring of oxidative skin stress by ultraweak photon emission (UPE)-measurement. I: mechanisms of UPE of biological materials.

Abstract: Background/purpose: Oxidation of proteins and amino acids is associated with generation of ultraweak photon emission (UPE), which may be used to assess oxidative processes in the skin in a non-invasive way. This first part of a series of reports addresses the physicochemical basis of oxidation-induced UPE in the skin, with a special focus on the contribution of amino acid oxidation. Methods: UPE of biological samples and protein/amino acid solutions following oxidation with H2O2 in the presence of Fe2+ was recorded using a sensitive photomultiplier system. Signals were analyzed with regard to overall signal intensity and spectral distribution. Results: Increasing concentrations of H2O2 in aqueous bovine serum albumin solutions induced linearly correlated UPE and protein carbonyl compounds, with a substantially higher sensitivity for the measurement of UPE. In single amino acid solutions, strong UPE signals were generated by oxidation from Phe, Trp, His, and Cys, and weak signals from Lys and Thr. Analysis of reaction products by MS revealed high oxidative material turnover for Cys and His, whereas barely detectable oxidative material turnover seems to be sufficient to generate a UPE signal of similar strength from Trp and Phe. Combination of different amino acids did not result in a simple addition of individual oxidation-induced UPE signals, but in interactions ranging from antagonism to clear synergism. Synergism was evident between Trp- and UPE-generating amino acids such as Thr, Cys, and His, with the strongest synergism by far observed between Trp and His. The strikingly different individual UPE spectra of His and Trp, despite being of comparable overall strength, were congruent with a pure Trp UPE spectrum after combining His with Trp in solution, indicating energy transfer between both amino acids. Combination of Trp and DNA, which also gives UPE signals following oxidation, did not result in a synergistically enhanced or antagonized overall UPE signal, but in a simple addition of individual UPE signals. Conclusion: Measurement of UPE could be proven to be a highly sensitive method to assess oxidative processes in biological molecules. The reported data indicate that UPE generated by oxidation stressed skin is mainly due to non-fluorescent photon emission via Trp, whereby Trp acts as an energy receptor from other excited species of oxidation-modified amino acids.

Development and validation of a new Skin Color Chart

Abstract: BackgroundAge-induced skin color variations are of great importance and incite increasing demand for cosmetic products to improve the appearance. The evaluation by clinicians or estheticians of the efficacy of skin care products is particularly difficult and requires the help of color charts.Purpose

A randomized, prospective study using the LPG® technique in treating radiation-induced skin fibrosis: clinical and profilometric analysis

Abstract: Background/purpose: Cutaneous fibrosis is the quite mandatory sequela after a breast cancer treated by radiotherapy and it induces more or less important functional troubles. The LPG® technique is a technique of mechanical massage that allows skin mobilization by folding/unfolding. The aim of this study was to evaluate the changes on irradiated skin before and after LPG treatment by clinical and skin replica analysis. Methods: Twenty women, 43–55 years old, who had been treated from 6 to 16 months before, for breast cancer with a conservative surgery and radiotherapy, had been enrolled in the trial. They were divided into two groups after randomization: the first group was LPG treated three times a week for 1 month; the second group was only placed under medical supervision. The clinical criteria studied were systematically studied before (T0), at the end of treatment (T1) and 1 month after the end of treatment (T2): pain, itching, skin dryness, erythema, skin infiltration, feeling of tightness and of induration of the skin. Softening of the skin was assessed at T1 and T2. Cutaneous replica was performed on the internal upper 1/4 of each breast with silicone material before, after and 1 month later after the end of the treatment. After polymerization, the replica was stored and then blindly analyzed by image analysis software. The following parameters were systematically measured: average skin roughness, average of wrinkles' depth and residual length, wrinkle number and the space between them. Results: Clinically, the LPG treatment induced a decrease of erythema (10% of the patients vs. 40% before treatment), a decrease of pain and pruritus (10% vs. 20% and 40%, respectively) and a decrease of the feeling of induration of the skin (10% of the patients vs. 70% before treatment). Furthermore, a skin-softening sensation was noted by seven patients vs. one in the control group. Replica shows an increase of roughness and of furrow depth without any change in the residual length and an increase in the space between the wrinkles, whose number decreases. Conclusion: This study confirms the impact of the clinical sequelae induced on skin after radiotherapy and shows improvement of the clinical signs after treatment by the LPG® technique. The latter induces changes of micro relief, suggesting a softening effect on the skin. These preliminary results have to be confirmed on a more important group of patients.

Change of biophysical properties of the skin caused by ultraviolet radiation-induced photodamage in Koreans.

Abstract: Background/purpose Ultraviolet (UV) irradiation affects the function and complexion of the skin by inducing changes in physical properties through formation of erythema, proliferation of epithelial cells, DNA damage, activation or inactivation of various enzymes and proteins, and free radical formation. In this study, the authors intended to observe the overall course of changes in barrier function and reflectance of the skin induced by photodamage, and healing reaction in the course of time, and alteration of the skin complexion. Methods The subjects were chosen from 15 healthy Korean men 20-35 in age, that fall into the category of Fitzpatrick's skin types II, III, and IV without history of recent exposure to sunlight, photosensitivity, or having taken any drugs that induce phototoxicity or photoallergic reactions. The subjects were artificially exposed to suberythemogenic dose [0.5 minimal erythemal dose (MED), 0.75 MED], 1 MED and high dose (2.5 MED) by solar simulator, and changes in skin barrier function and skin reflectance were assessed with a Tewameter, a Corneometer, and a Colorimeter for 4 weeks. Results Transepidermal water loss (TEWL) increased abruptly at Day 1 of single solar UV (SSUV) exposure, and slowly returned to the original level from Day 2/Day 3. In the case of exposure with 0.75 MED, it returned to the original level at Day 4 of exposure, and at Days 7 and 28 in the cases of 1 MED and 2.5 MED exposure, respectively. Water-holding capacity sharply declined at Day 1 of exposure, hitting the lowest point at Day 2, and then slowly recovered starting on Day 3. In the case of exposure with 0.75 MED and 1 MED, it returned to the original level at Days 7 and 28 in the case of 2.5 MED exposure. The a(*) values abruptly increased and reached the peak at Day 1 and slowly returned to the original level at Day 2, while the b(*) values slowly increased at Day 3, peaking at Day 7 and slowly returning to the original level thereafter. The L(*) values abruptly declined at Day 1, maintaining plateau through Day 7 and slowly returning to the baseline level thereafter. The individual typology angle (ITA degrees ) were compatible with L(*) values change. The erythema index increased abruptly at Day 1 of SSUV exposure, peaking at Day 2 and slowly returned to the original level starting at Day 3. Melanin index slowly started to increase on Day 3 of SSUV exposure, peaking at Day 7 and gradually returned to the original level thereafter. However, L(*), a(*), b(*), erythema index, and melanin index did not return to the original level during the 28-day course of this study. Conclusion This study shows that in the skin of Korean subjects, changes in skin barrier function and delayed melanization do occur even in exposure to a suberythemogenic dose of SSUV. Also, given the fact that restoration of barrier function occurs as the process of melanization begins, melanization is considered to be a useful predictive indicator of the restoration of the skin barrier function after sunburn.

In vivo study of skin mechanical properties in Raynaud's phenomenon

Abstract: Background/aim: Raynaud's phenomenon (RP) is usually the first symptom in patients with systemic sclerosis (SS) and may precede skin changes by several months or years. Non-invasive measurements of skin elasticity are very sensitive and appropriate for objective and quantitative evaluation of sclerodermatous skin. The aim of this study was to investigate and compare the mechanical properties of the skin in patients with primary, secondary, and suspected secondary RP. Materials/methods: A total of 63 patients were studied. They were classified as having scleroderma-type nailfold capillary abnormalities – 17 with indurative phase of scleroderma (group 1), nine with edematous phase of scleroderma (group 2), 18 with suspected secondary RP (group 3) and as having RP-type nailfold capillary abnormalities, 19 with primary RP (group 4). Thirty-nine sex- and age-matched healthy individuals with normal nailfold capillaroscopy pattern were also studied as controls. Mechanical properties of the skin were evaluated using a non-invasive suction device (Cutometer) equipped with a 2 mm probe. Measurements were performed over five anatomic regions: cheeks, volar forearms, wrists, hands, and proximal phalanx of the fingers. The skin mechanical parameters analyzed were distensibility (Uf), elasticity (Ua/Uf) and viscoelasticity (Uv/Ue). Results: Most demonstrative changes were observed over volar forearms. Patients included in groups 1–3 were characterized by significantly lower Uf and higher Uv/Ue compared with patient group 4 and controls. Patient groups 1 and 2 showed significantly lower Ua/Uf, as well. There were no significant differences in skin mechanical parameters between patient group 4 and control group. Conclusion: Mechanical properties of the skin in patients with suspected secondary RP significantly differ from these in patients with primary RP and resemble those in patients with edematous phase of scleroderma. Our findings suggest that the non-invasive measurements of skin elasticity could be helpful in identifying patients with RP at risk of developing SS.

Melanocytic skin lesions and pregnancy: digital dermoscopy analysis.

Abstract: Background: Very few studies have tried to clarify how pregnancy influences the morphology of pigmented skin lesions (PSL). Our purpose was to objectively determine, by digital dermoscopy analysis (DDA), any dermoscopic changes of acquired melanocitic nevi during pregnancy and after 1 year from delivery. Methods: Thirty-five healthy pregnant women and 35 age-matched female controls were enrolled in the study. Nevi of pregnant women were analysed by DDA between 5 and 8 weeks of pregnancy, between 39 and 41 weeks of pregnancy and 12 months after delivery. Nevi of control women were analysed by DDA in a month of the year matching the period of recruitment of pregnant women and 21 months later. Results: Multivariate analysis of variance (manova) for repeated measures revealed that dermoscopic variables SKIN-GREEN-AVERAGE, SKIN-BLUE-AVERAGE and CONTRAST changed during pregnancy but returned to non-significant values after a year from delivery. The variable ENTROPY showed significant differences between initial evaluation and 1 year after delivery. Finally, the variable VARIANCE OF BORDER GRADIENT showed a significant difference between the first and the last evaluations, in both pregnant and control subjects. Conclusions: The study showed that pregnancy leads to significant modifications in PSL, especially with regard to pigment network, globules and architectural order or disorder.

Allergy patch test reading from photographic images: disagreement on ICDRG grading but agreement on simplified tripartite reading.

Abstract: Background/aims: The International Contact Dermatitis Research Group (ICDRG) system for clinical scoring of allergic patch test reactions is well established in clinical dermatology for detailed scoring of allergic reactions. The degree of redness and the presence of swelling, papules, vesicles and bullae are assessed based on visual examination and palpation of reactions. In photographic assessment used in research and tele-dermatology, the scoring is solely based on visual examination of photos. The aim of the study was to evaluate inter-expert variation in patch test reading using photographic images, with ICDRG reading as a reference. Material and methods: Five experienced senior dermatologists each scored 55 positive patch test reactions from 16 slides in an office environment. The slides showed pictures of patch tests with different allergens. The scoring system by ICDRG with six categories for scoring was used. Results: The five dermatologists performed the scoring very differently. When the scoring system was simplified to a tripartite scoring system, the scoring was performed almost similarly by the five clinicians. Conclusion: Based on the present results, it is proposed that the number of scoring categories should be minimized and simplified into negative (including doubtful) reactions, positive reactions and irritant reactions. Such simplified tripartite reading is proposed for research purposes and for tele-dermatology, when scoring is based on photographic images. © Blackwell Munksgaard 2007.

Air-exposed keratinocytes exhibited intracellular calcium oscillation.

Abstract: We previously demonstrated that calcium propagation plays a crucial role in epidermal homeostasis when the epidermis was exposed to a dry environment In the present study, we first demonstrated the intracellular calcium oscillation in cultured human skin keratinocytes On partial exposure of cultured human keratinocytes to air, a transient increase of intracellular calcium concentration appeared, followed by a wave-like increase in the unexposed keratinocytes, showing oscillations with a frequency that varied from cell to cell There appeared to be no correlation between the oscillation frequencies in adjacent cells The increase of calcium concentration did not appear when calcium was removed from the medium or when suramin, a purinergic receptor antagonist, was added The ATP concentration also increased immediately after keratinocytes were exposed to air We hypothesize that ATP is secreted from keratinocytes on exposure to air, and induces an increase of intracellular calcium concentration

Functional analyses of the eyelid skin constituting the most soft and smooth area on the face: contribution of its remarkably large superficial corneocytes to effective water-holding capacity of the stratum corneum.

Abstract: Background/purpose: The eyelid constitutes a unique area on the face because of its soft, smooth and thin skin distinct from that of other facial portions. Its softness facilitates their easy compliance to blinking movement, which is indispensable to protect the wet surface of the eyeball. Moreover, the skin of the eyelid does not show any prominent follicular orifices or an oily appearance even in adults. Despite such uniqueness, its biophysical characteristics have remained unclear as compared with other facial skin. Methods: We conducted non-invasive instrumental measurements on the skin of the upper eyelid of 22 healthy Japanese adults in comparison with those of the adjacent facial skin, i.e. the cheek and nose. Additionally, we examined 10 adult patients with atopic dermatitis (AD) whose facial skin remained clinically free from skin lesions for at least 2 months. Results: The eyelid skin showed high transepidermal water loss like other facial skin. Its skin surface hydration state was as high as that of the adjacent skin, despite the fact that the eyelid skin revealed extremely low amounts of surface lipids unlike its neighboring skin regions. However, in contrast to small corneocytes found in other facial areas, the corneocytes of the eyelid skin displayed a significantly larger surface size, suggesting that slow turnover of its stratum corneum (SC) takes place to allow sufficient maturation of the corneocytes, enabling them to exert efficient water-binding capacity. Its pH tended to be higher than that of the adjacent skin. Its superficial blood flow was significantly higher than that of others, although skin color assessment showed lower color values for redness than those of the other facial skin sites. In clinically non-lesional skin of adult AD patients, we found increased blood circulation and a higher parameter for redness, suggesting the presence of invisible mild inflammation in the dermis even long after subsidence of visible inflammatory changes. Conclusion: Our present biophysical findings suggest that, although the eyelid skin is poor in surface lipids, its extraordinary large superficial corneocytes play an important role in maintaining sufficient hydration state of its skin surface to keep it soft and flexible, enabling its good compliance with the blinking movement.

Exogen hair characterization in human scalp.

Abstract: Background/aim: Classically, the hair cycle is described as a sequence of three successive phases: a hair-growth phase named anagen, a regression phase or catagen and a resting phase or telogen. In rodents, it appears that the resting hair follicle population contains also a new phase that has been identified recently as the exogen phase of the hair cycle. This phase leads to the release of the telogen club and results in hair shedding. The aim of this paper is to propose a method that is applicable to humans and that is able to discriminate the two components of the resting hair population i.e. the telogen and the exogen hair follicles. Methods: We used non-invasive approaches to entrap exogen scalp hair into silicon-based polymers. We also extracted growing and non-growing hair with a calibrated dynamometer. We characterized differences between anagen, catagen, telogen and exogen root ends with histochemical stains and with the scanning electron microscope. Furthermore, we documented all known hair-cycle stages with the contrast-enhanced phototrichogram (CE-PTG) technique. Results: We demonstrated that anagen and telogen hair are firmly anchored to the hair follicle and that cohesion forces are correlated with hair thickness. On the contrary, exogen hair are passively retained within the hair follicle. Among the resting hair population, telogen clubs retain cellular elements of the outer root sheaths that are not found on exogen hair. The specificity of the new exogen collection method was documented with the simultaneous use of the CE-PTG method: indeed anagen, catagen and telogen follicles remain unaffected by the exogen extraction procedure. Conclusion: Exogen hair can be sampled specifically from the human scalp with a new non-invasive method. Our data suggest that the casual levels of exogen hair, in normal individuals and under the present experimental conditions, are usually less than seven hair per cm2.