Quantification of allergic and irritant patch test reactions using ImageJ.

BACKGROUND/AIMS: It is often difficult to differentiate between allergic and irritant patch test reactions by visual inspection. The purpose of this study was to test an image analysis-based method that differentiates between the two reactions by quantifying the degree of erythema at the patch test site. METHODS: A total of 172 Japanese patients were patch-tested with sodium lauryl sulfate (SLS) and nickel sulfate, followed by digital photography and visual evaluation of the patch test areas by dermatologists at 48 and 72 h. The digital images were converted to erythema index (EI) images by image processing, and changes in ΔEI (the difference in the EI between the patch test site and the adjacent normal skin) values were analyzed. RESULTS: The ΔEI was significantly increased at 72 h relative to that at 48 h for positive nickel sulfate reactions (P < 0.0001), while no significant difference in the ΔEI was found for SLS reactions. CONCLUSION: Using image analysis, allergic patch test reactions may be distinguished from irritant reactions by evaluating the change in the degree of erythema at 48 and 72 h.

The degrees of UVB-induced erythema and pigmentation correlate linearly and are reduced in a parallel manner by topical anti-inflammatory agents.

To examine whether it is possible to evaluate the degree of ultraviolet B (UVB)-induced inflammation by measuring the degree of hyperpigmentation, we investigated the relationship between UVB-induced erythema and the subsequent pigmentation quantitatively. At 24 h and 7 d after irradiation with erythemogenic doses of UVB to the backs of 16 Japanese subjects, the degree of induced erythema (delta erythema index) and that of pigmentation (delta melanin index) were examined by an image analytic method using a videomicroscope interfaced with a computer. The relationship between two indices was linear in each subject, and the correlation coefficient was 0.83 when evaluated using whole data. The slope of the regression line for the delta melanin index against delta erythema index tended to become steeper as non-irradiated skin color became darker (r = 0.63), suggesting that more efficient melanogenesis takes place after the same level of inflammation in the subject with darker skin. Both erythema and hyperpigmentation were suppressed significantly and in a parallel manner by corticosteroids and indomethacin applied topically immediately after UVB irradiation. These results imply that the post-inflammatory hyperpigmentation correlates closely with the severity of the prior inflammation and that chemical mediators released in the inflammatory process have considerable influence on the melanogenesis. We conclude that the measurement of UVB-induced hyperpigmentation can be utilized for the assessment of topical anti-inflammatory agents, unless these have direct actions on the tyrosinase activity of melanocytes.

Localized heat urticaria: a clinical study using laser Doppler flowmetry.

We studied the pathophysiology of localized heat urticaria using laser Doppler flowmetry (LDF) in two patients with this rare disease. In heat challenge tests, performed with different challenge times and temperatures, a heat stimulator with a thermoregulated metal disc was utilized. Immediately after removal of the heat source, cutaneous blood flow (CBF) changes in the tested sites were monitored with LDF. In both patients the increase in (CBF) took place at some intervals after a heat challenge, synchronous with the start of the urticarial response. This interval, or the latency time (LT), showed distinct inverse proportion to the intensity of heat stimuli and was prolonged by effective treatments, such as application of antihistamines and repeated heat exposure by LDF. Therefore, the time of latency might be regarded as a good indicator of the severity of illness and therapeutic effectiveness, and thus might reflect the relationship between the degree of heat stimuli and the releasing process of chemical mediator(s) in patients with localized heat urticaria (LHU).

Measurement of skin color: practical application and theoretical considerations.

Quantification of erythema and/or pigmentation is important for in vivo assessment of skin reactions to external stimuli such as ultraviolet radiation. Measurement of lesional color is also useful for quantitative evaluation of the efficacy of therapies for skin lesions. Several types of portable optoelectronic instruments have recently become available for these purposes and have been applied to research in dermatology, physiology, pharmacology, and cosmetic science. As color is not a genuine physical quantity but a sensory perception based on color vision, any colorimetric data obtained for the skin should be interpreted carefully. Erythema and melanin indices derived from skin reflectance data should also be evaluated in relation to the optical properties of the skin to avoid misuse. In this article, various methods for quantifying skin color and related parameters are reviewed and the characteristics of each method are discussed theoretically using an optical model of the skin.

A case of episodic angioedema associated with eosinophilia.

BACKGROUND: Gleich et al. first described 4 cases of episodic angioedema associated with eosinophilia as a distinct entity in 1984. Since then, several cases of this disorder have been reported in the United States, Europe and Japan. OBSERVATIONS: We report a case of a 22-year-old pregnant Japanese woman with this disorder. She had no fever and her general condition was good except the angioedema which was limited to her limbs. During an acute episode, her white blood cell count increased to 29,500/mm3 with 50% eosinophils, following an elevated serum interleukin-5 (IL-5) level. Spontaneous resolution occurred in 1 month after the onset. In a 5 month follow-up, no evidence of cardiac or other visceral organ involvement was found, and no recurrence occurred. CONCLUSIONS: Our case, combined with those reported in the literature, suggests that Japanese cases of episodic angioedema associated with eosinophilia differ from Caucasian cases in clinical symptoms and some other points.

Relationship between hematocrit and CO2 contents in whole blood and true plasma.

The amount of CO2 liberated out of the red cell was measured by decreasing PCO2 in human blood with different fractional hematocrits of about 0.24, 0.45, and 0.75, respectively, in order to elucidate whether it depends on the hematocrit and the intracellular pH. From a venous PCO2 level the PCO2 of the sample blood was lowered to 12 Torr. PCO2, CO2 content, pH, Cl-, and Na+ were measured in whole blood and true plasma before and after the reduction of PCO2. Change in water concentration in plasma was calculated from change in plasma Na+ concentration. The bicarbonate shift well counterbalanced to the Cl- shift. As the hematocrit was decreased, the amount of CO2 released per mol of hemoglobin increased, while the change in intracellular bound CO2 concentration decreased. That is, the intracellular bound CO2 became higher in the lower hematocrit blood than in the higher hematocrit one. This fact suggested that the intracellular pH became higher as the hematocrit was lowered, and thus the amount of alkali bound with hemoglobin or the CO2 release was enhanced. The Donnan ratio of the bound CO2 at 12 Torr was independent of the hematocrit, though the pH was inversely related to the hematocrit.

Derivation of theoretical equations of the CO2 dissociation curve and the carbamate fraction in the Haldane effect.

The simultaneous Henderson-Hasselbalch equations in plasma and red cell were solved in order to obtain the CO2 dissociation curve of oxygenated blood. In order to solve the above two equations the following equation was added, in which the relationship between the intracellular (delta pHC) and the extracellular pH change (delta pHP) was defined as follows: pHC = (1 + sigma) delta pHP, where 1 + sigma is a factor to be determined from experimental data on Donnan's ratio for H+. From the solution, the ratio of bicarbonate shift to the CO2 quantity released out of or combined with hemoglobin was calculated. The solution was validated by comparing the above ratio between the theoretical and experimental data. The CO2 contents calculated at 12 Torr in whole blood, red cell, and plasma compartments show good agreement with the respective analyzed values. When the buffer values of hemoglobin and plasma buffer protein were 70.0 and 7.5 mmol/(liter plasma X pH), respectively, sigma = -0.21 + 0.05 X delta pHP, and the Donnan's ratio for HCO3- was assumed to be 0.7 at pH = 7.33, the theoretical CO2 dissociation curve fitted well with the experimental curve. The CO2 dissociation curve of deoxygenated blood was expressed by adding the measured Haldane effect to the CO2 content of oxygenated blood. This additive characteristic in turn made it possible to estimate carbamate contribution in the Haldane effect.

Transcutaneous Po2 and Pco2 measurement in dermatology.

Although transcutaneous Po2 (tcPo2) and Pco2 (tcPco2) measurement was originally developed for the non-invasive Pao2 and Paco2 monitoring, its utilization in dermatology is discussed in this article. Our experimental and clinical studies have revealed that tcPo2 is easily influenced and reduced by various skin changes, such as hyperkeratosis, acanthosis, cellular infiltrate and fibrosis as well as the circulatory disturbance in the skin, and that tcPco2 is kept stable except in ischemic or bullous lesions. Although tcPo2 could be a marker reflecting the severity of some lesions, simultaneous measurement of tcPco2 and cutaneous blood flow would offer more precise information about the circulation and respiration in the skin.

Transcutaneous PO2 and PCO2 measurements in various skin lesions.

Low tcPO2 levels were observed in various skin lesions, indicating that most pathological changes in the skin induce such a reduction. In contrast, the tcPCO2 changed less, with the exception of marked elevations in bullous or prenecrotic lesions. This procedure may have practical applications in clinical dermatology, particularly in quantitating the response to therapy and in predicting a necrotic change.

Striated muscle hamartoma of the nostril.

We observed two females, an 11-month old and a 15-year-old, each with a round, soft mass in the nostril. Histologically, numerous bundles of striated muscle fibers were seen in the masses among normal dermal components. The lesions were excised without complications. Four patients with similar lesions confirmed clinically and histologically have been reported in the literature under various diagnostic names. These masses were diagnosed as striated muscle hamartomas in view of their characteristic features: congenital round, soft masses on the midline of the head or neck with multiple, mature striated muscles observed in the mass. Since these lesions may be associated with such anomalies as amniotic band syndrome and lipoma of the brain, a complete medical examination is required of such patients.

Bowen's disease on the sole: p16INK4a overexpression associated with human papillomavirus type 16.

We report a case of Bowen's disease on the sole presenting clinically as an exophytic, blackish-grey, verrucous tumour, and showing human papillomavirus (HPV) type 16 on analysis with polymerase chain reaction. Positive stains for HPV particles by immunohistochemical analysis were limited to several cell nuclei at the upper stratum Malpighii. However, all the tumour cells in the epidermis exhibited strong and diffuse nuclear and cytoplasmic stains for the tumour suppressor protein p16INK4a. We speculate that dysregulation of the retinoblastoma/p16INK4a pathway may be involved in the pathogenesis of the lesion, and p16INK4a overexpression might serve as a useful surrogate marker for identifying Bowen's disease harbouring high-risk types of HPV infection.

Variation in color and blood flow of the forearm skin during orthostatic maneuver.

To investigate the influence of arm position on the color and blood flow of the forearm skin, the CIE L*a*b* values, the erythema and melanin indices, and laser-Doppler blood flow values were recorded at three different arm positions (lowered, heart level and raised) in 15 healthy subjects using three kinds of optoelectronic instruments. The values of almost all color parameters, including the melanin index, changed stepwise significantly following the change in the arm position, and blood flow values decreased significantly during arm lowering. These results are most likely due to complex changes in the volume, flow rate and oxygen saturation level of the blood in the superficial vascular plexus, and their influences on each parameter were discussed. To use these instruments effectively for the quantitative evaluation of skin test reactions, a standardized arm position should be kept when the test is carried out in the forearm.

Measurement of color parameters of psoriatic plaques by narrow-band reflectance spectrophotometry and tristimulus colorimetry.

Color parameters were measured on 50 psoriatic plaques in 10 patients, after scoring the amount of scales on them by inspection, with a narrow-band reflectance spectrophotometer (erythema/melanin index expression) and tristimulus colorimeter (CIE L*a*b* expression). Both erythema index a* (redness) were highest in the group of erythematous plaque with little scale (twice as high as in controls) and decreased significantly as the plaques were covered with thicker scale, while L* (brightness) changed in just the opposite fashion of a*. These portable 'color indicators' can be utilized to express the appearance of psoriatic plaques quantitatively, especially the extent of erythema and the amount of the scale on it.

Comparison of narrow-band reflectance spectrophotometric and tristimulus colorimetric measurements of skin color. Twenty-three anatomical sites evaluated by the Dermaspectrometer and the Chroma Meter CR-200.

Two types of portable reflectance instruments, tristimulus colorimeters (Chroma Meter CR-200) and narrow-band spectrophotometers (Dermaspectrometer), have recently become available for the quantification of skin color. In order to know the difference and the relationship between the different color systems, the CIE L*a*b* system and the erythema melanin (E/M) indices, respectively, adopted by the two, the variations in skin color were measured at 23 different anatomical sites of 10 healthy Caucasian male subjects. The reddish tint of the skin color of the face, palm and sole was readily detected by either of them in the increase in the a* value or in the E index, and a strong linear correlation (r = 0.92, p < 0.001) was noted between the two values. The fair color appearance of the trunk was detected in the high L* value and in the low M index, but the correlation between the two was much less significant (r = -0.56, p < 0.001). Although the mean b* values were highest in the trunk, they are significantly lower on the non-light-exposed side than those on the light-exposed side of the arm. The correlation between the b* value and the M index was weak.

Contact dermatitis due to 2,2'-azobis(2-amidinopropane) dihydrochloride: an outbreak in production workers.

2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) is an azo compound which has been used as a radical chain initiator. The purpose of this study was to confirm contact sensitivity to AAPH in individuals who were engaged in the production of AAPH, and presented with prolonged eczematous eruptions mainly on exposed areas. Patch testing was carried out with AAPH (1 and 5% aq.) on 8 patients and 6 healthy volunteers who had never been exposed to this chemical. All patients showed a strong positive patch test reaction to this agent, while all control subjects showed negative results. Because this chemical has recently been used for studies on the oxidation of biological materials, not only production workers in the chemical industry but also medical researchers should avoid prolonged exposure to this agent.

Image analysis of the distribution of turnover rate in the stratum corneum.

BACKGROUND/AIMS: A common method to evaluate turnover rate in the stratum corneum is to measure the change in fluorescence intensity with time after dyeing the stratum corneum with fluorescent pigments. If these changes in fluorescence over time are carefully observed, the rate of decline in fluorescence intensity differs among different small areas on the skin surface. A possible relationship between these differences and dry skin has been reported. The purpose of this research was to develop a method for analyzing turnover rate in the stratum corneum in each small area on the surface of the skin as well as to investigate the variations in the inconsistencies of turnover rate. METHODS: The stratum corneum at six body regions (forehead, cheek, forearm, opisthenar, back and lower leg) was dyed with dansyl chloride (DC), and the change in fluorescence intensity over time was imaged with a highly sensitive television camera through special filters. Then, the fluorescent distribution in the images was analyzed to measure the change in fluorescence intensity with time among the small areas. Also, the decline in fluorescence intensity observed was categorized using specific characteristics into six different types. RESULTS: By attaching a filter to an ultraviolet (UV) light source in order to transmit light at the excitation wavelength and a filter to the camera lens to transmit light at the wavelength of DC fluorescence, we could image the low intensity fluorescent light from the DC without interference from the UV light exciting the DC. The characteristics of the variation in the decline in fluorescence intensity were categorized into six patterns. Type I: pattern showing a uniform decline in fluorescence intensity. Type II: pattern showing sporadic areas where fluorescence intensity declines quickly. Type III: pattern showing relatively large areas where fluorescence intensity declines slowly. Type IV: pattern showing sporadic areas of fluorescence intensity, matched with locations of keratotic plugs. Type V: pattern showing sporadic fluorescent areas, not matched with locations of keratotic plugs. Type VI: pattern showing a partial, drastic decline in fluorescence intensity occurring on inflamed skin after sunburn. CONCLUSIONS: By analyzing the image generated from a highly sensitive television camera equipped with special filters, we could measure turnover rate of the stratum corneum at any small area. The variations in Types IV and V were believed to be derived from keratotic plugs and closed comedo. Except for Type VI, observed on significant skin inflammation, Type II and Type III were believed to be the patterns that reflected variations in turnover rate in stratum corneum itself.

A simple method to estimate CIE-L*a*b* values of the skin from its videomicroscopic image.

BACKGROUND/AIMS: The C I E (Commission Internationale de I'Eclairage)-L*a*b* is the most popular standardized color system. The purpose of this study was to develop a simple method for estimating C I E-L*a*b* values of the skin using a video microscope and a computer. METHODS: Skin images were obtained with a video microscope of various anatomical locations and ultraviolet B-induced erythema and pigmentation in seven subjects. R G B (red, green, and blue) color coordinates of the images were converted into quasi-L*a*b* values using formulae similar to those defined by C I E. These values were compared with C I E-L*a*b* values simultaneously measured with a colorimeter. RESULTS: The correlation coefficients between C I E- and quasi-L*a*b* values were 0.97 (L*), 0.91 (a*), and 0.84 (b* CONCLUSIONS: Our method may be useful for deriving CIE-L*a*b* values of the skin from its video microscopic image.

High-frequency ultrasound characterization of normal skin. Skin thickness and echographic density of 22 anatomical sites.

BACKGROUND/AIMS: Variation in skin thickness relative to anatomical site was little studied in the past. Biopsy cutting and histological processing change tissue geometry. High-frequency ultrasound allows in vivo measurement of skin thickness of multiple sites. The object was to map regional differences in skin thickness. METHODS: 22 different anatomical sites were studied. The Dermascan C (20 MHz) was used. The acoustic density of the dermis and the epidermal entrance echo was analyzed by the in-built image analysis software. 18 healthy volunteers aged 24-41 years were studied. RESULTS: Extremity skin was thinner than truncal skin, and acoustically dense. Females had thinner and more dense skin in comparison with males. Skin of the palm, sole and the head was thick but weak in density, and the biological variation in the dermis/subcutaneous tissue interphase does not allow highly accurate evaluation in these special sites. There was an overall inverse correlation between skin thickness and acoustic density with thin skin being dense and thick skin being relatively echo-poor. CONCLUSIONS: Skin thickness and acoustic density reflecting intradermal structure exhibit systematic regional variation with thin and dense skin on extremities in comparison with the trunk and special ultrasound profiles in selected sites such as the face, the palp and sole. Female skin is thinner and more dense in comparison with male skin.