Skin color measurements in terms of CIELAB color space values

In vivo determination of the diclofenac skin reservoir: comparison between passive, occlusive, and iontophoretic application

Aim

There is scarce information concerning the pharmacodynamic behavior of topical substances used in the physiotherapy setting. The aim of the present study was to estimate the formation and emptying of the diclofenac (DF) skin reservoir after passive, semiocclusive, and electrically assisted applications of DF.

Subjects and methods

Five different groups of healthy volunteers (n_total=60, 23 male and 37 female), participated in this study. A 1% DF (Voltaren Emulgel) formulation (12 mg) was applied on the volar forearms on randomized defined circular skin areas of 7 cm². DF was applied for 20 minutes under three different conditions at the same time. The presence of DF in the skin results in a reduction of the methyl nicotinate (MN) response. To estimate the bioavailability of DF in the skin, MN responses at different times following initial DF application (1.5, 6, 24, 32, 48, 72, 96, and 120 hours) were analyzed.

Results

At 1.5 hours after the initial DF application, a significant decrease in MN response was detected for the occluded and iontophoretic delivery. Passive application resulted in a decrease of the MN response from 6 hours post-DF application. The inhibition remained up to 32 hours post-DF application for the iontophoretic delivery, 48 hours for the occluded application, and 72 hours for the passive delivery. At 96 and 120 hours post-DF application none of the MN responses was inhibited.

Conclusion

The formation and emptying of a DF skin reservoir was found to be dependent on the DF-application mode. Penetration-enhanced delivery resulted in a faster emptying of the reservoir.

Accuracy of self-reported nevus and pigmentation phenotype compared with clinical assessment in a population-based study of young Australian adults

BACKGROUND

Awareness of individual risk may encourage improved prevention and early detection of melanoma.

METHODS

We evaluated the accuracy of self-reported pigmentation and nevus phenotype compared with clinical assessment, and examined agreement between nevus counts from selected anatomical regions. The sample included 456 cases with invasive cutaneous melanoma diagnosed between ages 18 to 39 years and 538 controls from the population-based Australian Melanoma Family Study. Participants completed a questionnaire about their pigmentation and nevus phenotype, and attended a dermatologic skin examination.

RESULTS

There was strong agreement between self-reported and clinical assessment of eye color [κ, = 0.78; 95% confidence interval (CI), 0.74-0.81]; and moderate agreement for hair color (κ = 0.46; 95% CI, 0.42-0.50). Agreement between self-reported skin color and spectrophotometer-derived measurements was poor (κ = 0.12; 95% CI, 0.08-0.16) to moderate (Spearman correlation rs = -0.37; 95% CI, -0.32 to -0.42). Participants tended to underestimate their nevus counts and pigmentation; men were more likely to underreport their skin color. The rs was 0.43 (95% CI, 0.38-0.49) comparing clinical total body nevus counts with self-reported nevus categories. There was good agreement between total body nevus counts and site-specific nevus counts, particularly on both arms.

CONCLUSIONS

Young adults have suboptimal accuracy when assessing important risk characteristics including nevus numbers and pigmentation. Measuring nevus count on the arms is a good predictor of full body nevus count.

IMPACT

These results have implications for the likely success of targeted public health programs that rely on self-assessment of these factors.

Cosmetics Alter Biologically-Based Factors of Beauty: Evidence from Facial Contrast

The use of cosmetics by women seems to consistently increase their attractiveness. What factors of attractiveness do cosmetics alter to achieve this? Facial contrast is a known cue to sexual dimorphism and youth, and cosmetics exaggerate sexual dimorphisms in facial contrast. Here, we demonstrate that the luminance contrast pattern of the eyes and eyebrows is consistently sexually dimorphic across a large sample of faces, with females possessing lower brow contrasts than males, and greater eye contrast than males. Red-green and yellow-blue color contrasts were not found to differ consistently between the sexes. We also show that women use cosmetics not only to exaggerate sexual dimorphisms of brow and eye contrasts, but also to increase contrasts that decline with age. These findings refine the notion of facial contrast, and demonstrate how cosmetics can increase attractiveness by manipulating factors of beauty associated with facial contrast.

The Atopic Dermatitis Antecubital Severity score: validity, reliability, and sensitivity to change in patients with atopic dermatitis

BACKGROUND

The Atopic Dermatitis Antecubital Severity (ADAS) score is a new objective scale for the assessment of the severity of atopic dermatitis (AD). It is calculated by multiplying the intensity of inflammatory signs by the size of an antecubital eczema lesion.

AIM

To test the validity, reliability, and sensitivity to changes of the ADAS score compared with those of the Eczema Area and Severity Index (EASI) score.

METHODS

Forty patients with AD were enrolled and treated with a moisturizer. At baseline, and in weeks 1 and 2, two independent evaluators measured the ADAS score, the EASI score, and the investigator's global assessment score rated on a six-point scale.

RESULTS

The ADAS score showed a higher validity than the EASI score. The superiority of the ADAS to the EASI was prominent in mild AD. Inter-evaluator reliability was excellent in both the ADAS score and the EASI. The sensitivity to changes was higher in the ADAS score than in the EASI score.

CONCLUSIONS

The ADAS score may be used as a simple scoring system with good validity, reliability, and sensitivity to changes, especially in patients with mild-to-moderate AD.

Time course of skin features and inflammatory biomarkers after liquid sulfur mustard exposure in SKH-1 hairless mice

Sulfur mustard (SM) is a strong bifunctional alkylating agent that produces severe tissue injuries characterized by erythema, edema, subepidermal blisters and a delayed inflammatory response after cutaneous exposure. However, despite its long history, SM remains a threat because of the lack of effective medical countermeasures as the molecular mechanisms of these events remain unclear. This limited number of therapeutic options results in part of an absence of appropriate animal models. We propose here to use SKH-1 hairless mouse as the appropriate model for the design of therapeutic strategies against SM-induced skin toxicity. In the present study particular emphasis was placed on histopathological changes associated with inflammatory responses after topical exposure of dorsal skin to three different doses of SM (0.6, 6 and 60mg/kg) corresponding to a superficial, a second-degree and a third-degree burn. Firstly, clinical evaluation of SM-induced skin lesions using non invasive bioengineering methods showed that erythema and impairment of skin barrier increased in a dose-dependent manner. Histological evaluation of skin sections exposed to SM revealed that the time to onset and the severity of symptoms including disorganization of epidermal basal cells, number of pyknotic nuclei, activation of mast cells and neutrophils dermal invasion were dose-dependent. These histopathological changes were associated with a dose- and time-dependent increase in expression of specific mRNA for inflammatory mediators such as interleukins (IL1β and IL6), tumor necrosis factor (TNF)-α, cycloxygenase-2 (COX-2), macrophage inflammatory proteins (MIP-1α, MIP-2 and MIP-1αR) and keratinocyte chemoattractant (KC also called CXCL1) as well as adhesion molecules (L-selectin and vascular cell adhesion molecule (VCAM)) and growth factor (granulocyte colony-stimulating factor (Csf3)). A dose-dependent increase was also noted after SM exposure for mRNA of matrix metalloproteinases (MMP9) and laminin-γ2 which are associated with SM-induced blisters formation. Taken together, our results show that SM-induced skin histopathological changes related to inflammation is similar in SKH-1 hairless mice and humans. SKH-1 mouse is thus a reliable animal model for investigating the SM-induced skin toxicity and to develop efficient treatment against SM-induced inflammatory skin lesions.

Proposed shade guide for human facial skin and lip: a pilot study

STATEMENT OF PROBLEM

Currently, no commercially available facial shade guide exists in the United States for the fabrication of facial prostheses.

PURPOSE

The purpose of this study was to measure facial skin and lip color in a human population sample stratified by age, gender, and race. Clustering analysis was used to determine optimal color coordinates for a proposed facial shade guide.

MATERIAL AND METHODS

Participants (n=119) were recruited from 4 racial/ethnic groups, 5 age groups, and both genders. Reflectance measurements of participants' noses and lower lips were made by using a spectroradiometer and xenon arc lamp with a 45/0 optical configuration. Repeated measures ANOVA (α=.05), to identify skin and lip color differences, resulting from race, age, gender, and location, and a hierarchical clustering analysis, to identify clusters of skin colors) were used.

RESULTS

Significant contributors to L*a*b* facial color were race and facial location (P<.01). b* affected all factors (P<.05). Age affected only b* (P<.001), while gender affected only L* (P<.05) and b* (P<.05). Analyses identified 5 clusters of skin color.

CONCLUSIONS

The study showed that skin color caused by age and gender primarily occurred within the yellow-blue axis. A significant lightness difference between gender groups was also found. Clustering analysis identified 5 distinct skin shade tabs.

Relating physico-chemical properties of frozen green peas (Pisum sativum L.) to sensory quality

BACKGROUND

The acceptability of frozen green peas depends on their sensory quality. There is a need to relate physico-chemical parameters to sensory quality. In this research, six brands of frozen green peas representing product sold for retail and caterer's markets were purchased and subjected to descriptive sensory evaluation and physico-chemical analyses (including dry matter content, alcohol insoluble solids content, starch content, °Brix, residual peroxidase activity, size sorting, hardness using texture analysis and colour measurements) to assess and explain product quality.

RESULTS

The sensory quality of frozen green peas, particularly texture properties, were well explained using physico-chemical methods of analysis notably alcohol insoluble solids, starch content, hardness and °Brix. Generally, retail class peas were of superior sensory quality to caterer's class peas although one caterer's brand was comparable to the retail brands. Retail class peas were sweeter, smaller, greener, more moist and more tender than the caterer's peas. Retail class peas also had higher °Brix, a(*) , hue and chroma values; lower starch, alcohol insoluble solids, dry matter content and hardness measured.

CONCLUSIONS

The sensory quality of frozen green peas can be partially predicted by measuring physico-chemical parameters particularly °Brix and to a lesser extent hardness by texture analyser, alcohol insoluble solids, dry matter and starch content.

Evaluation of different methods for determination of the iron saturation level in bovine lactoferrin

Lactoferrin (Lf) samples with ca. 25%, 50%, 75%, 85% and 100% iron saturation were prepared for the purpose of evaluating Chromametry, Differential Scanning Calorimetry (DSC) and Circular Dichroism (CD) spectropolarimetry for their suitability in determining the iron saturation level. Numerical values for colour from Chromametry, enthalpy change of denaturation (ΔHcal) from DSC and molar ellipticities from CD were statistically analysed to evaluate their correlation with the level of iron saturation in Lf. Linear regression analysis of colour coordinates Chroma (C(∗)) and hue (h°) angle on percentage iron saturation level of Lf showed that the values can be used to estimate the iron saturation level. The ΔHcal for the iron saturated peak and the CD ellipticities in the 310-340 nm region provided reliable data for the estimation of iron saturation level of Lf up to 75%. Mono- and di-saturated Lf displayed the same thermal stability and very similar tertiary structures.

MC1R genotype as a predictor of early-onset melanoma, compared with self-reported and physician-measured traditional risk factors: an Australian case-control-family study

Background

Melanocortin-1 receptor (MC1R) gene variants are very common and are associated with melanoma risk, but their contribution to melanoma risk prediction compared with traditional risk factors is unknown. We aimed to 1) evaluate the separate and incremental contribution of MC1R genotype to prediction of early-onset melanoma, and compare this with the contributions of physician-measured and self-reported traditional risk factors, and 2) develop risk prediction models that include MC1R, and externally validate these models using an independent dataset from a genetically similar melanoma population.

Methods

Using data from an Australian population-based, case-control-family study, we included 413 case and 263 control participants with sequenced MC1R genotype, clinical skin examination and detailed questionnaire. We used unconditional logistic regression to estimate predicted probabilities of melanoma. Results were externally validated using data from a similar study in England.

Results

When added to a base multivariate model containing only demographic factors, MC1R genotype improved the area under the receiver operating characteristic curve (AUC) by 6% (from 0.67 to 0.73; P < 0.001) and improved the quartile classification by a net 26% of participants. In a more extensive multivariate model, the factors that contributed significantly to the AUC were MC1R genotype, number of nevi and previous non-melanoma skin cancer; the AUC was 0.78 (95% CI 0.75-0.82) for the model with self-reported nevi and 0.83 (95% CI 0.80-0.86) for the model with physician-counted nevi. Factors that did not further contribute were sun and sunbed exposure and pigmentation characteristics. Adding MC1R to a model containing pigmentation characteristics and other self-reported risk factors increased the AUC by 2.1% (P = 0.01) and improved the quartile classification by a net 10% (95% CI 1-18%, P = 0.03).

Conclusions

Although MC1R genotype is strongly associated with skin and hair phenotype, it was a better predictor of early-onset melanoma than was pigmentation characteristics. Physician-measured nevi and previous non-melanoma skin cancer were also strong predictors. There might be modest benefit to measuring MC1R genotype for risk prediction even if information about traditional self-reported or clinically measured pigmentation characteristics and nevi is already available.

Topical efficacy of dimercapto-chelating agents against lewisite-induced skin lesions in SKH-1 hairless mice

Lewisite is a potent chemical warfare arsenical vesicant that can cause severe skin lesions. Today, lewisite exposure remains possible during demilitarization of old ammunitions and as a result of deliberate use. Although its cutaneous toxicity is not fully elucidated, a specific antidote exists, the British anti-lewisite (BAL, dimercaprol) but it is not without untoward effects. Analogs of BAL, less toxic, have been developed such as meso-2,3-dimercaptosuccinic acid (DMSA) and have been employed for the treatment of heavy metal poisoning. However, efficacy of DMSA against lewisite-induced skin lesions remains to be determined in comparison with BAL. We have thus evaluated in this study the therapeutic efficacy of BAL and DMSA in two administration modes against skin lesions induced by lewisite vapor on SKH-1 hairless mice. Our data demonstrate a strong protective efficacy of topical application of dimercapto-chelating agents in contrast to a subcutaneous administration 1h after lewisite exposure, with attenuation of wound size, necrosis and impairment of skin barrier function. The histological evaluation also confirms the efficacy of topical application by showing that treatments were effective in reversing lewisite-induced neutrophil infiltration. This protective effect was associated with an epidermal hyperplasia. However, for all the parameters studied, BAL was more effective than DMSA in reducing lewisite-induced skin injury. Together, these findings support the use of a topical form of dimercaprol-chelating agent against lewisite-induced skin lesion within the first hour after exposure to increase the therapeutic management and that BAL, despite its side-effects, should not be abandoned.

Colour analysis of the equine endometrium: comparison of spectrophotometry and computer-assisted analysis of photographs within the L*a*b* colour space system

The aims of this study were to compare two different methods of quantifying the colour of the luminal surface of the equine endometrium and to relate the results to histopathological evidence of inflammation and fibrosis. The mucosal surfaces of 17 equine uteri obtained from an abattoir were assessed using a spectrophotometer and by computer-assisted analysis of photographs. Values were converted into L(*)a(*)b(*) colour space. Although there was significant correlation between the two methods of quantification, variations in 'brightness', 'red' and 'yellow' values were noted. Within a given uterus, measurements using the spectrophotometer did not differ significantly. Using photographic analysis, brightness differed between horns, although no differences in chromaticity were found. Histopathological classification of changes within endometria corresponded to measured differences in colour. Extensive fibrosis was associated with increased brightness and decreased chromaticity using both methods. Inflammation correlated with reduced chromaticity, when measured by spectrophotometry, and with reduced brightness and yellow values, when assessed photographically. For this technique to gain wider acceptance as a diagnostic tool, e.g. for the endoscopic evaluation of uterine mucosae in vivo, standardised illumination techniques will be required so that colours can be compared and interpreted accurately.

Colorful DNA polymorphisms in humans

In this review article we summarize current knowledge on how variation on the DNA level influences human pigmentation including color variation of iris, hair, and skin. We review recent progress in the field of human pigmentation genetics by focusing on the genes and DNA polymorphisms discovered to be involved in determining human pigmentation traits, their association with diseases particularly skin cancers, and their power to predict human eye, hair, and skin colors with potential utilization in forensic investigations.

An 8-week face-split study to evaluate the efficacy of cosmeceuticals using non-invasive bioengineering devices

BACKGROUND/AIMS

Even with the increasing demand for functional cosmeceuticals in the recent years, objective standard criteria for assessing their efficacy are currently incomplete at best. In this 8-week face-split study, in which we topically applied high-priced cosmeceuticals on one side and more affordable cosmeceuticals on the other side of the face, we compared the efficacy of these two products using non-invasive bioengineering technology.

METHODS

We assessed the efficacy of a skin-whitening and an anti-wrinkle cosmeceutical product on 25 and 19 healthy female volunteers, respectively. In a single blind split setting, each participant received an 8-week topical application of high-priced cosmeceuticals to the left side of the face, and cheaper cosmeceuticals to the right side. Then, the subjects' biophysical parameters were measured for an objective evaluation of the results. This was followed by a questionnaire to obtain a subjective assessment.

RESULTS

There was no significant difference in the change between the high-priced cosmeceuticals and the more affordable cosmeceuticals. At each measured site, there were variable changes including skin improvement and aggravation at the end of study. The subjective questionnaire demonstrated also that the participants perceived no difference in the efficacy between the two products.

CONCLUSIONS

Our results showed that there were no significant differences in the skin biophysical parameters following the application with high-priced functional cosmeceuticals or less expensive cosmeceuticals. The subject failed to differentiate between the two products. The development of objective standard criteria for assessing its efficacy is essential.

Update on techniques for the quantitation of facial skin characteristics

The purpose of this article is to review the strategies and methods for quantifying treatment outcomes, perhaps defined by the consumer/patient as a "decrease in perceived age." The demand for the rejuvenation of facial skin is expected to increase as the population ages and seeks optimal outcomes from the array of available treatment modalities. This information will be of value to the plastic surgeon in collaborating with patients on evaluation and treatment strategies.

Making sense of skin color in clinical care

The background of this article is that assessment and quantification of skin color is important to health care; color is one indicator of overall health and is linked to oxygenation, tissue perfusion, nutritional status, and injury. The purpose is to describe how skin color varies across racial/ethnic groups so that the information can be applied to clinical practice. The method used is cross-sectional, descriptive design (n = 257). We recorded self-defined race/ethnicity and used a spectrophotometer to measure skin color at two anatomic sites. Skin color variables included L* (light/dark), a* (red/green), and b* (yellow/blue). As regards results, we found significant differences in L*, a*, and b* values by site and race/ethnicity in White, Asian, and Biracial participants. L*: F(3, 233) = 139.04, p < .01 and F(3, 233) = 118.47, p < .01. Black participants had significantly lower mean L* values and wider ranges of L*, a*, and b* as compared with other groups. In regard to application, these findings suggest that clinicians and researchers should plan and provide care based on skin color, rather than race/ethnicity.

Effects of ultraviolet light on human serum 25-hydroxyvitamin D and systemic immune function

BACKGROUND

Many immune-mediated diseases are associated with low levels of vitamin D and sunlight. UV light or supplementation with vitamin D can increase regulatory T-cell activity and prevent animal models of autoimmune disease. Increasing population vitamin D levels may therefore alleviate the burden of human immune-mediated disease.

OBJECTIVE

To determine the responses of circulating 25-hydroxyvitamin D [25(OH)D] levels, regulatory T-cell numbers, and immune function to UV light exposure in patients being treated for skin disease.

METHODS

Twenty-four subjects with skin disease from the North of Scotland were recruited between December and March. At baseline, and after 2 and 4 weeks of narrowband UV light exposure, we measured peripheral blood 25(OH)D level, numbers of regulatory T cells (CD4(+)CD25(hi)FoxP3(+)), and T-cell proliferative and cytokine responses to anti-CD3/CD28 stimulation.

RESULTS

Median (interquartile range) narrowband UV-B received during the study was 39.1 (30.9) as standard erythema dose, comparable to a quarter of the median summer sunlight exposure received locally. This increased the 25(OH)D level from a mean ± SD of 34 ± 17 nmol/L to 58 ± 16 nmol/L after 2 weeks and 78 ± 19 nmol/L after 4 weeks. The mean proportion of circulating regulatory T cells increased from 0.5% to 1.6% CD3(+) cells, which significantly correlated with the increased 25(OH)D level. UV treatment was also followed by reduced proliferative and IL-10 responses to anti-CD3/CD28 independent of the 25(OH)D level.

CONCLUSION

Narrowband UV light reduces systemic immune responsiveness via the induction of regulatory T cells. Light and 25(OH)D levels may affect particular immune functions independently. The levels of serum 25(OH)D over which these effects are apparent should guide future interventions.

Assessment methods for the evaluation of vitiligo

There is no standardized method for assessing vitiligo. In this article, we review the literature from 1981 to 2011 on different vitiligo assessment methods. We aim to classify the techniques available for vitiligo assessment as subjective, semi-objective or objective; microscopic or macroscopic; and as based on morphometry or colorimetry. Macroscopic morphological measurements include visual assessment, photography in natural or ultraviolet light, photography with computerized image analysis and tristimulus colorimetry or spectrophotometry. Non-invasive micromorphological methods include confocal laser microscopy (CLM). Subjective methods include clinical evaluation by a dermatologist and a vitiligo disease activity score. Semi-objective methods include the Vitiligo Area Scoring Index (VASI) and point-counting methods. Objective methods include software-based image analysis, tristimulus colorimetry, spectrophotometry and CLM. Morphometry is the measurement of the vitiliginous surface area, whereas colorimetry quantitatively analyses skin colour changes caused by erythema or pigment. Most methods involve morphometry, except for the chromameter method, which assesses colorimetry. Some image analysis software programs can assess both morphometry and colorimetry. The details of these programs (Corel Draw, Image Pro Plus, AutoCad and Photoshop) are discussed in the review. Reflectance confocal microscopy provides real-time images and has great potential for the non-invasive assessment of pigmentary lesions. In conclusion, there is no single best method for assessing vitiligo. This review revealed that VASI, the rule of nine and Wood's lamp are likely to be the best techniques available for assessing the degree of pigmentary lesions and measuring the extent and progression of vitiligo in the clinic and in clinical trials.

Hyperbaric oxygen improves ultraviolet B irradiation-induced melanin pigmentation and diminishes senile spot size

BACKGROUND

The effects of exposure to hyperbaric oxygen on ultraviolet B (UVB) irradiation-induced melanin pigmentations of skins and on senile spot sizes of faces were investigated.

METHODS

In the first experiment, male subjects were irradiated with UVB on their upper arms for inducing erythema and the subsequent melanin pigmentation. They were exposed to a hyperbaric environment at 1.25 atmospheres absolute (ATA) with 32% oxygen for 1 h/day, three times per week. In the second experiment, female subjects were exposed to a hyperbaric environment at 1.25 ATA with 32% oxygen for 1 h/day, two times per week.

RESULTS

In the first experiment, melanin pigmentations lightened after 4 weeks of exposure to hyperbaric oxygen. In the second experiment, senile spot sizes became small after 12 weeks of exposure to hyperbaric oxygen.

CONCLUSION

We concluded that exposure to hyperbaric oxygen used in this study accelerates both the fading in melanin pigmentation and the decrease in senile spot size.

Objective and quantitative evaluation of scar color using the L*a*b* color coordinates

Scar color evaluation by clinical physicians has been based on subjective judgments. The purpose of this study was to investigate the application of a novel photographic analysis to produce an objective and quantitative measurement of scar color using the L*a*b* color coordinates. Three plastic surgeons evaluated photos of 207 scars using the clinical scar assessment scale developed by Beausang et al. Scar color was subjectively classified as group 1 (perfect match), 2 (slight mismatch), 3 (obvious mismatch), or 4 (gross mismatch). Three general physicians quantified color differences between the scar and the surrounding normal skin using the L*a*b* color coordinates. The total color difference (DeltaT*) and the color differences for each coordinate (DeltaL*, Deltaa*, and Deltab*) were calculated. The measurement was performed 3 times with a 4-week interval. Group 1 contained 51 scars, group 2 had 68, group 3 had 46, and group 4 had 42. The mean (SD) total color difference values (DeltaT*) for each group were 4.4 (1.83), 9.55 (2.18), 17.76 (2.96), and 29.06 (9.45), respectively (P < 0.001). The mean of each color coordinate (DeltaL* = light to dark, and Deltaa* = green to red) also differed between the groups, except in groups 1 and 2. The mean Deltab* (blue to yellow) did not differ between the groups. The correlation coefficients for interrater reliability and test-retest consistency were satisfactory. Objective scar evaluation using the L*a*b* color coordinates is found to be a reliable method to quantify scar color. With further study, this method could be simple and effective to assess the effects of scar management.

Use of reflectance spectrophotometry and colorimetry in a general linear model for the determination of the age of bruises

Bruises can have medicolegal significance such that the age of a bruise may be an important issue. This study sought to determine if colorimetry or reflectance spectrophotometry could be employed to objectively estimate the age of bruises. Based on a previously described method, reflectance spectrophotometric scans were obtained from bruises using a Cary 100 Bio spectrophotometer fitted with a fibre-optic reflectance probe. Measurements were taken from the bruise and a control area. Software was used to calculate the first derivative at 490 and 480 nm; the proportion of oxygenated hemoglobin was calculated using an isobestic point method and a software application converted the scan data into colorimetry data. In addition, data on factors that might be associated with the determination of the age of a bruise: subject age, subject sex, degree of trauma, bruise size, skin color, body build, and depth of bruise were recorded. From 147 subjects, 233 reflectance spectrophotometry scans were obtained for analysis. The age of the bruises ranged from 0.5 to 231.5 h. A General Linear Model analysis method was used. This revealed that colorimetric measurement of the yellowness of a bruise accounted for 13% of the bruise age. By incorporation of the other recorded data (as above), yellowness could predict up to 32% of the age of a bruise-implying that 68% of the variation was dependent on other factors. However, critical appraisal of the model revealed that the colorimetry method of determining the age of a bruise was affected by skin tone and required a measure of the proportion of oxygenated hemoglobin, which is obtained by spectrophotometric methods. Using spectrophotometry, the first derivative at 490 nm alone accounted for 18% of the bruise age estimate. When additional factors (subject sex, bruise depth and oxygenation of hemoglobin) were included in the General Linear Model this increased to 31%-implying that 69% of the variation was dependent on other factors. This indicates that spectrophotometry would be of more use that colorimetry for assessing the age of bruises, but the spectrophotometric method used needs to be refined to provide useful data regarding the estimated age of a bruise. Such refinements might include the use of multiple readings or utilizing a comprehensive mathematical model of the optics of skin.

Estimation of postmortem interval based on the spectrophotometric analysis of postmortem lividity

The color of postmortem lividity and control skin in 21 adult cadavers whose postmortem interval was within 72h, was measured by spectrophotometry in order to estimate the postmortem interval, objectively. The L *a *b * system, which has been widely used for the digital expression of skin color, was used and linear regression analysis was performed to determine the relationship between the postmortem interval and 31 color factors including L * (Value), a * and b * (Chroma and Hue) and C * (Chroma). The difference in Chroma between postmortem lividity and control skin (DeltaC * and DeltaC( *)/C(c)( *)) was only weakly correlated with the postmortem interval. We propose a new equation for calculating the postmortem interval using several color factors obtained by measurement of postmortem lividity, together with some autopsy findings that are known to affect the formation of postmortem lividity. The new equation makes it possible to estimate the postmortem interval within +/-4.76h.

A study of a method for distribution analysis of skin color

BACKGROUND/AIMS

The objective and quantitative assessment of the skin is important in medical and cosmeceutical research. Assessment of color is an important element for analyzing the surface of the skin, which is usually determined subjectively by a doctor or using color analysis devices. These devices, however, cannot provide correct color information because color is construed from the mean value of the observation region, and analysis of color distribution is impossible. The purpose of this paper is to develop an objective analysis method to permit skin color measurement of each pixel unit of an image and analyze the distribution of skin surface color.

METHODS

The Skin Color Distribution Analyzer (SCDA) is an analysis method newly developed at the Research Institute for Skin Image at Korea University. The SCDA system presented in this paper performed a novel form of quantitative and objective analysis of skin color distribution using each pixel color model parameter found in image wavelength information. In this paper, distribution analysis was conducted on normal skin and skin lesions and skin affected by artificially induced irritant contact dermatitis and pigmented nevous. The method selected a grade using a color model parameter. Twenty healthy Korean males participated in this study. A comparative study of the eight anatomical areas was performed, including the exposure and non-exposure parts and the medial aspect and the lateral aspect of the forearm. A reliability test for the SCDA system was also conducted with a spectrometer (SPEC) using the color analysis method.

RESULTS

Each skin lesion was precisely segmented by grade and each parameter had a different statistical significance for results of analysis of distribution in pigmented nevous and the artificially induced irritant contact dermatitis. Parameters L(*), b(*), a(*), and EI showed salient traits. Showed resemble measured result in the SCDA system and the SPEC of normal skin. The exposed site, in comparison with the non-exposed site, showed a notable difference in the L(*) parameter and a significant statistical difference in the x and z parameters, except b(*). The comparison of the medial and lateral aspects of the forearm showed a notable difference in the L(*) parameter and a significant statistical difference in the parameters except y and b(*). In the reliability test result using the SCDA system and the SPEC, the SCDA system was highly reliable in terms of the CV value in all color model parameters.

CONCLUSIONS

The color distribution analysis method using the SCDA system has revealed an aspect that the existent method of medical research has not shown, and is considered to be more reliable than other methods. This method can provide better study findings because it can be applied to other fields in addition to the medical science field and the ripple effect is thought to be bigger in other science field too.

Standardization of in vitro macrophotography for assessment of cutaneous responses

The increased popularity of commercially available three-dimensional human skin equivalents in recent years has allowed for assessment of melanogenesis modulated by compounds topically applied to the skin or directly incorporated from the medium. These skin equivalents provide a suitable model for elucidating the mechanisms of action of various factors that modulate skin pigmentation or other properties of the skin. As such, researchers need to objectively quantify cutaneous responses at the macroscopic level. A simple method to standardize macrophotography images is reported that can quantify cutaneous responses in human skin equivalents of Asian, Black or African American, and Caucasian or White racial/ethnic origin. Macrophotographs are analyzed using the Commission Internationale de l'Eclairage L*a*b* color space system in combination with a personal computer and image editing software. Pigmentation changes monitored over a 9 day period showed a high correlation with melanin content evaluated in Fontana-Masson-stained sections. These results indicate the feasibility of using a macrophotography setup in a sterile tissue culture environment to objectively assess in vitro cutaneous responses in human skin equivalents. This serves as an adjunct tool to biochemical and morphological methods to effectively quantify changes in pigmentation over time.

Skin Color is Associated with Insulin Resistance in Nondiabetic Peritoneal Dialysis Patients

Background

Changes in skin color are common among dialysis patients. They are associated with urochrome pigments, hemoglobin, and changes in cutaneous vasculature. Insulin resistance (IR) is strongly linked to cutaneous vascular dysfunction and is prevalent in dialysis patients. We postulated skin color may be associated with IR in dialysis patients because of the alternation in cutaneous vasculature.

Methods

50 nondiabetic peritoneal dialysis (PD) patients were recruited for measurements of skin color by the Commission Internationale de I'Eclairage (CIE; International Commission on Illumination) system (“L” “a” “b” system). The “L” values represent skin brightness, “a” redness, and “b” yellowness. Correlation analysis between skin color, homeostatic model assessment (HOMAIR), high-density lipoprotein cholesterol (HDL-C), and adiponectin was performed.

Results

We divided patients (age 45 ± 13 years, 31 women) into 3 groups according to tertiles of HOMAIR. Patients with higher HOMAIR had a trend to have poor skin color (lower “a” and “b” values; p = 0.038 and 0.064). HOMAIR, adiponectin, and HDL-C levels were correlated with “a” and “b” values in logarithm (all p < 0.05). After adjustments for age, hemoglobin level, duration of PD, and residual renal glomerular filtration rate, only HOMAIR was associated with “a” values ( p = 0.038) and HDL-C was associated with “b” values ( p = 0.048) in logarithm.

Conclusions

Skin color, measured noninvasively, is associated with HOMAIR and HDL-C. Nondiabetic PD patients that had more severe IR had worse skin color.

Dynamics of pigmentation induction by repeated ultraviolet exposures: dose, dose interval and ultraviolet spectrum dependence

BACKGROUND

The dynamics of ultraviolet (UV)-induced melanogenesis have been well characterized for single UV exposures. However, our knowledge of the effects of repeated UV exposures on the development of new pigmentation is limited.

OBJECTIVES

To characterize the dynamics and dose dependence of pigmentation induction by repeated UV exposures using two different UV sources.

METHODS

A total of 40 healthy subjects participated in the study: 21 were exposed to a 5% UVB/95% UVA source and 19 were exposed to a 2% UVB/98% UVA source. Skin phototypes 2-3 were represented. Subjects were exposed one to three times per week. The minimal erythemal dose and minimal melanogenic dose of all subjects were determined, and both visual and instrumental observations of the development of pigmentation and erythema were recorded.

RESULTS

Dark-brown pigmentation could be produced by a cumulative UV dose of 4200 J m(-2) given as 10 exposures over 5 weeks. However, comparable pigmentation could also be induced by a cumulative dose of 2900 J m(-2) given as eight exposures over 4 weeks. The lowest cumulative dose of 1900 J m(-2) given over 4 weeks produced moderate pigmentation. The 2% UVB source led to earlier and darker pigmentation than the 5% UVB source did for equally erythemogenic doses.

CONCLUSIONS

These observations show that the dynamics of melanogenesis induced by repeated exposures depends on UV dose, dose interval and emission spectrum. They also indicate that increasing the UV dose above a certain level of cumulative exposure does not significantly increase the level of UV-induced pigmentation.

Objective assessment of psoriasis erythema for PASI scoring

Skin colour is vital information in dermatological diagnosis. It reflects pathological condition beneath the skin and commonly being used to indicate the extent of a disease. Psoriasis is a skin disease which is indicated by the appearance of red plaques. Although there is no cure for psoriasis, there are many treatment modalities to help control the disease. To evaluate treatment efficacy, PASI (Psoriasis Area and Severity Index) which is the current gold standard method is used to determine severity of psoriasis lesion. Erythema (redness) is one parameter in PASI. Commonly, the erythema is assessed visually, thus leading to subjective and inconsistent result. In this work, we proposed an objective assessment of psoriasis erythema for PASI scoring. The colour of psoriasis lesion is analyzed by DeltaL, Deltahue, and Deltachroma of CIELAB colour space. References of lesion with different scores are obtained from the selected lesions by two dermatologists. Results based on 38 lesions from 22 patients with various level of skin pigmentation show that PASI erythema score can be determined objectively and consistent with dermatology scoring.

In vivo documentation of cutaneous inflammation using spectral imaging

Typical manifestations of cutaneous inflammation include erythema and edema. While erythema is the result of capillary dilation and local increase of oxygenated hemoglobin concentration, edema is characterized by an increase in extracellular fluid in the dermis, leading to local tissue swelling. Both of these inflammatory reactions are typically graded visually. We demonstrate the potential of spectral imaging as an objective noninvasive method for quantitative documentation of both erythema and edema. As examples of dermatological conditions that exhibit skin inflammation we applied this method on patients suffering from (1) allergic dermatitis (poison ivy rashes), (2) inflammatory acne, and (3) viral infection (herpes zoster). Spectral images are acquired in the visible and near-IR part of the spectrum. Based on a spectral decomposition algorithm, apparent concentrations maps are constructed for oxyhemoglobin, deoxyhemoglobin, melanin, optical scattering, and water. In each dermatological condition examined, the concentration maps of oxyhemoglobin and water represent quantitative visualizations of the intensity and extent of erythema and cutaneous edema, correspondingly. We demonstrate that spectral imaging can be used to quantitatively document parameters relevant to skin inflammation. Applications may include monitoring of disease progression as well as screening for efficacy of treatments.

New approach to the evaluation of skin color of pigmentary lesions using Skin Tone Color Scale

Objective methods of measuring skin color are needed to evaluate pigmentary lesions quantitatively. We have developed a new method of measuring skin color using a plastic bar system called the Skin Tone Color Scale based on Munsell's color space system. We have also evaluated the effectiveness of various therapies using this measurement system. Our system was designed to measure skin color in normal skin, pigmentary lesions of solar lentigo, chloasma and ephelides, and postinflammatory pigmentation. Moreover, effectiveness of various therapies for these pigmentary lesions was evaluated. The evaluations made with this system were closely related to physician assessment. This method may be useful in measuring of skin color and evaluating the effectiveness of therapies for pigmentary diseases.