bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between anatomical skin site and response to halcinonide and methyl nicotinate studied by bioengineering techniques
Authors: Clarys P. , Manou I. , Barel A.
Published: October 2006

Background/aims:

Regional differences in percutaneous penetration and skin properties are well documented. However, only a few studies have investigated the relationship between substance penetration and specific skin characteristics in function of the body region. It was our aim to evaluate the physiological effect of topically applied substances in function of skin parameters determined at different body regions.

Methods:

The characterization of the blanching response to a topically applied corticosteroid and the characterization of the erythema response to topically applied nicotinates were used as two indicators for the percutaneous penetration at selected body regions. Stratum corneum hydration, skin temperature, TEWL, the amount of skin surface lipids and perfusion of the superficial microcirculation were determined at the same body regions.

Results:

Significant differences in pharmacodynamic response to the corticosteroids and the nicotinates were found in function of the body region. A strong correlation was detected between the parameters characterizing the pharmacodynamic response and the particular skin properties.

Conclusion:

The regional differences in pharmacological response to topically applied halcinonide and nicotinates may point to a body region dependent bioavailability of the vasoactive substances in the upper skin layers. The significant relationship between the parameters characterizing the physiological skin reaction and the determined skin parameters may be an indication of their involvement in the percutaneous penetration process. These regional differences in pharmacological response seem to be independent of the physicochemical properties of the topically applied substances.
Low‐level luminescence of the human skin
Authors: Cohen S. , Popp F. A.
Published: October 2006

Background/aims/methods:

For the first time systematic measurements of the low‐level luminescence of the human skin (“bi‐ophotons”) have been performed by means of a photon detector device set up in darkness.

Results:

Several months of daily investigations have shown that body light emission follows definite and well‐known biological rhythms, such as 14 days, 1 month, 3 months, 9 months, and reflects the left‐right symmetry of the body. The results confirm that biophotons are related to physiological functions.

Conclusions:

This technique provides a new and powerful noninvasive diagnostic method. In particular, skin research and development may use it for testing the influence of different skin treatments.
Objective assessment of the minimal irritant reaction induced by a 70% solution of glycolic acid
Authors: Mantovani Lucia , Belletti Barbara , Seidenari Stefania
Published: October 2006

Background/aims:

Glycolic acid has become a very popular cutaneous improving agent, but, despite its increasing employment, its biophysiological effects on the skin have not been adequately examined. Recently, we described subclinical skin damage induced by a 70% solution of glycolic acid applied on forearm skin by means of non‐invasive measuring techniques. In the present study we instrumentally assessed the cutaneous effects induced by a glycolic acid minimal irritant dose on the volar aspect of the right forearm.

Methods:

Twenty subjects, seventeen women and three men, aged 16 to 56, were tested with 40 nl of a 70% solution of glycolic acid applied on one volar forearm area until a clincally evident cutaneous reaction occurred. Visual scoring, TEWL measurement, skin colour, capacitance and echographic recordings were performed before the beginning of the experiment and 30 min and 3, 24, 48 and 72 h after glycolic acid removal. The echo‐graphic recordings were carried out using a 20 MHz B scanner (Dermascan C), and then were processed by dedicated software based on segmentation procedures. Two amplitude intervals were selected for the elaboration of the images, the first marking the hyporeflecting areas of the dermis, the second highlighting both the hyperreflecting parts of the epidermis and the lower dermis, separately.

Results:

Mean application‐time before the appearance of minimal inflammatory skin reactions was 25±7 min. Clinical evaluation was confirmed by the analysis of the colorimetric parameter a*. TEWL and capacitance values showed a marked increase, reaching their maximum at 30 min after solution removal, followed by a progressive decrease. Values of both parameters were statistically significant for up to 48 h. The elaboration of echographic images by a low amplitude interval showed dermal edema more pronounced at 30 min and 24 h, while by highlighting hyperreflecting areas an evident reduction of the entry echo for up to 3 h and a prolonged decrease of the reflectivity of the lower dermis were observable.

Conclusion:

Our data demonstrate that despite the persistence of higher TEWL values, glycolic acid induced irritation causes a prolonged increase in capacitance that corresponds to modifications in epidermal reflectivity. Epidermal alterations are associated with dermal edema, as evaluated by ultrasound.
Does low power laser light used in laser Doppler systems affect the sensory nerves?
Authors: Wårdell Karin
Published: October 2006

Background/aims:

Many subjects have stated that they can sense the laser light during cutaneous laser Doppler recordings. The aim of the study was therefore to investigate if low power laser light used in laser Doppler systems affects the sensory nerves.

Methods:

Single point recording as well as imaging was performed with the laser Doppler perfusion imager at the finger pulp, dorsal and ventral side of the hand and the forearm skin in 12 healthy volunteers. The hypothesis “the subject can not sense the laser beam” was tested by double blind random control of the on‐off pattern of the laser light reaching the skin. In total, 96 trials (each including 12 recordings) were performed. Furthermore, it was investigated if the blood flow level was influenced by the subjects “sense” of being measured.

Results:

The hypothesis was rejected in 92 out of 96 trials. Three of the trials that could not be rejected were recorded from the same subject. In further trials no reproducibility was found. The blood flow level was not influenced by the subjects “sense” of being measured.

Conclusions:

In general, the laser light used in laser Doppler imaging systems does not influence the sensory nerves. However, it can not be excluded that the laser light used in laser Soppier perfusion imaging (LDPI) affects sensory nerves under unknown circumstances and at specific spots in cutaneous tissue.
Nikolsky's sign: a novel way to evaluate damage at the dermal‐epidermal junction*
Authors: Braue E. H. , Nalls C. R. , Way R. A. , Zallnick J. E. , Rieder R. G. , Mitcheltree L. W.
Published: October 2006

Background/aims:

Sulfur mustard (2,2′‐dichlorodiethyl sulfide, HD) is a potent vesicating (blistering) agent. Cutaneous exposure causes the destruction of basal cells and leads to a separation at the dermal‐epidermal junction. To evaluate the efficacy of candidate antivesicant compounds, suitable animal models are needed. A tape stripping method and the Dermal Torque Meter (DTM) have been used in novel applications to evaluate for the Nikolsky's sign in the hairless guinea pig. The Nikolsky's sign is the separation and loss of the epidermis from the dermis when the skin is pressed with a sliding or twisting motion. The purpose of this study was to find an objective, reproducible, and quantitative method that could be used as an end‐point to evaluate the degree of damage at the dermal‐epidermal junction following cutaneous HD vapor exposure.

Methods:

Hairless guinea pigs were exposed to saturated HD vapor (1.4 mg/l) for time intervals between 2 and 9 min using 14‐mm vapor cups. At 24 h post‐exposure, both tape stripping (fabric carpet tape) and a DTM were used to produce the Nikolsky's sign in animals under anesthesia. Using the tape stripping method, 15‐mm disks of tape were applied to each skin site. After 5 s the tape was peeled off. The D T M was used to apply a horizontal twisting motion to the skin. The parameters included a 15‐mm center disk, a ring gap of 1 mm, a torque of 30 mNm, and a 5‐s cycle time. A cyanoacrylate adhesive was used to secure the center disk and guard ring to the skin. The loss of the epidermis was determined by visual observation and confirmed by histopathological examination. The standard D T M unit was modified to use multiple center disk/guard ring assemblies so that several sites on each animal could be evaluated at the same time.

Results:

The mean (±S E M) percent incidence of positive Nikolsky's sign observations using the tape stripping method for HD vapor exposures of 3,5,7, and 9 min was 0,50 (±16), 94 (±6.2), and 100, respectively. The mean (±S E M) percent incidence of positive Nikolsky's sign observations using the D T M method for HD vapor exposures of 2, 3, 4, and 5 min was 0, 25 (±7.1), 91 (±2.9), and 96 (±2.3), respectively.

Conclusions:

The Nikolsky's sign produced by the tape stripping method and the D T M were useful in evaluating damage at the dermal‐epidermal junction following cutaneous HD vapor exposures. These methods have the potential to replace histopathology as an end‐point for routine screening procedures designed to evaluate the efficacy of antivesicant compounds.
Baseline electrical impedance measurements at various skin sites – related to age and sex
Authors: Nicander Ingrid , Nyren Miruna , Emtestam Lennart , Ollmar Stig
Published: October 2006

Background/aims:

During previous studies on the electrical impedance of the skin, we formulated a set of four physical indices that could be used to distinguish between the cutaneous effects produced by different chemical irritants. We now employ the electrical impedance technique to compare the properties of different anatomical areas of the skin, using the same set of indices.

Methods:

Investigations were performed on 131 healthy volunteers, who were divided into four groups on the basis of age and sex. Readings of electrical impedance were taken from ten different regions over the body, and transepidermal water loss was measured for comparison.

Results:

Baseline values of electrical impedance of the skin were shown to vary, depending on the site. Age was also found to exert a major influence, causing an increase in the indices related to magnitude (MIX, RIX, and IMIX) with increasing age, and a decrease in that related to phase (PIX), while sex had only a marginal effect.

Conclusions:

As with other non‐invasive techniques, baseline characteristics differ from place to place over the body surface, and age is another important determining factor.
Cigarette smoking, cutaneous vasculature and tissue oxygen: an overview
Authors: Leow Yung‐Hian , Maibach Howard I.
Published: October 2006

Background/aims: This is an overview of the effects of cigarette smoking on the cutaneous blood flow and tissue oxygen.

Methods: Published reports on the use of bioengineering methods to evaluate the above are reviewed.

Conclusions: There is no one ideal method for studying the effect of cigarette smoking on the cutaneous vasculature. All studies suggest that smoking decreases cutaneous blood flow, but it is not certain if this effect is site‐specific. The tissue oxygen lowering effect of smoking could not be confirmed in all studies.
Quantification of vascular dysregulation in atopic dermatitis using laser Doppler perfusion imaging
Authors: Stäcker Markus , Heese Armin , Hoffmann Klaus , el Gammal Claudia , Altmeyer Peter
Published: October 2006

Background/aims: The reactivity of cutaneous microcirculation to prostaglandin liberators and histamine has a wide variation in man. Especially patients with atopic dermatitis show frequently altered reactions like the paradox anemic reaction to nicotinic acid esters and the abnormally weak reaction to intracutaneous histamine injection. We wanted to investigate the reproducibility and sensitivity of two‐dimensional laser Doppler perfusion imaging (LDPI) in quantifying these phenomena.

Methods: To study the reproducibility of LDPI, we measured the reaction to intracutaneous histamine injection and to application of nicotinic acid ester ointment at different time points and in contralateral body areas in 25 people with normal skin. In a second step, these stimuli were applied in 27 patients with atopic dermatitis and 23 normal controls in order to see whether LDPI is able to detect differences in the cutaneous vascular reaction between both groups.

Results: We found an excellent reproducibility of the parameters of LDPI measurements with regard to different locations (0.847≤r≤0.948) and time points (0.686≤r≤0.935). After epicut‐aneous application of nicotinic acid ester, there were significant smaller flow values in the marked center of the reaction in patients with atopic dermatitis compared to the control group. This corresponded to the paradox anemic reaction seen clinically in 15 of 27 patients. After intracutaneous injection of histamine, patients with atopic dermatitis showed significantly higher flow values in the center of reaction than normal controls because whealing was markedly reduced.

Conclusions: LDPI proved to be a reproducible and sensitive method for the follow‐up of vascular reactions.
Topographic measurement of skin color by narrow‐band reflectance spectrophotometer and minimal erythema dose (MED) in Koreans
Authors: Park Byung Soon , Youn Jai II
Published: October 2006

Background/aims: Narrow‐band reflectance spectrophotometer is one of the objective and quantitative devices for measuring the skin colors. There has been some controversy concerning the relationship between the objectively measured skin color and cutaneous responsiveness to ultraviolet radiation, including minimal erythema dose (MED). The aims of this study were to compare the color of Korean brown skin with that of Caucasians by objective measurement with the narrow‐band reflectance spectrophotometer, and to determine whether the skin color has any correlation with MED in Koreans, and demonstrate differences in this correlation according to the anatomical sites.

Methods: With narrow‐band reflectance spectrometer, skin colors were measured at 17 body sites of 20 healthy Korean male volunteers after measuring MED for the same subjects.

Results: The constitutional skin color, as measured by the melanin index of the nonexposed sites, showed a statistically significant correlation with MED values, whereas the facultative skin color did not. The Korean brown skin showed higher melanin index and lower erythema index compared with that of Caucasians.

Conclusions: We confirmed significant differences in the correlation between MED and melanin indices, depending on the anatomic sites. This suggests that selection from various sites, even among the nonexposed sites, is quite important and deserves further evaluation.
Diurnal volume changes of the lower legs in healthy males with a profession that requires standing
Authors: Krijnen R. M. A. , de Boer E. M. , Ader H. J. , Bruynzeel D. P.
Published: October 2006

Background/aims: The aims of this study are two‐fold: To determine intra‐individual volume changes of the lower legs in the course of a working day in healthy employees with a standing position at work; to relate complaints of the legs in healthy employees with volume changes in the course of the day.

Methods: Physical examination and Doppler ultrasound examination were used to exclude the presence of venous disorders. A questionnaire was used to assess complaints of the legs. The lower leg volume was measured with an optical leg volume meter on 2 or 3 days at the beginning and end of a full working day.

Results: Included were 197 male workers with a standing profession and no signs of venous insufficiency. The mean volume change of the lower leg was +1.8% for the left leg and +1.6% for the right leg. This volume increase was significant for both legs (P<0.05). A volume [1 volume unit (VU) is approximately 1 ml] increase of over 50 VU was found in 46% of the legs, mean 141 VU. An unchanged volume (‐50 VU to 50 VU) was found VU was found in 18% of the legs, mean ‐138 VU. Sixty‐four percent of the subjects reported subjective complaints of the legs. A tired feeling in the legs, restless legs and a sensation of swelling of the legs were equally present in all three groups of volume change. A statistically significant correlation between pain and a volume decrease was found for the left leg.

Conclusions: Diurnal volume changes of the lower legs were distributed as a Gaussian curve. A volume increase was common, but not obligatory. A volume increase of the legs was not associated with complaints of the legs or clinically evident oedema. This suggests that a volume increase can be a physiological phenomenon.
Sodium lauiyl sulphate damaged skin in vivo in man: a water barrier repair model
Authors: Zhai Hongbo , Poblete Nicholas , Maibach Howard I.
Published: October 2006

Background/aims: Few studies describe enhancing the repair of surfactant‐induced damaged skin. In vivo human studies were conducted to evaluate the efficacy of a topical agent after sodium lauryl sulphate (SLS) induced water barrier disruption.

Methods: Occlusive chambers with 1 % SLS were applied to the upper‐backs of volunteers for 24 h, removed and topical agents applied on the SLS‐treated skin sites daily for 5 days. Water barrier restoration was monitored by measuring transepidermal water loss (TEWL).

Results: The data were expressed as the percentage of recovery representing normalization of water barrier function. Results showed that a topical agent produced more rapid improvement in barrier function than its placebo vehicle, markedly accelerating repair at 48 h (P<0.01), and persisting throughout the experiment (P<0.05), in comparison with SLS‐control sites.

Conclusions: This study suggests that topical agents may accelerate the repair rates of water barrier function in SLS‐treated human skin. This model appears facile and robust for evaluating such repair.
Surface image analysis of nail alterations in juvenile pityriasis rubra pilaris
Authors: Piérard‐Franchimont Claudine , Piérard Gérald E.
Published: October 2006

Background/aims: Juvenile pityriasis rubra pilaris (PRP) is a rare disease that may alter the nail aspect. Image analysis after nail shadowing was used to quantify trachyonychia associated with juvenile PRR

Methods: The mean roughness (Ra) and the mean depth of roughness (Rz) of fingernails were measured three times at 3‐month intervals in nine children suffering from PRR The same measures were taken in 25 age‐matched normal individuals.

Results: Both profilometric parameters had higher values in the PRP group than in healthy subjects. The abnormal Ra and Rz values in patients showed variations unrelated to chronobiological cycles.

Conclusions: Nail shadowing image analysis is a reliable method to assess inconspicuous to moderate nail surface irregularities. In contrast with some other diseases, the aspect of polymorphic nails in PRP does not seem to be under chronobiological influence.
Skin temperature of UV‐induced erythema correlated to laser Doppler flowmetry and skin reflectance measured redness
Authors: Lock‐Andersen J. , Gniadecka M. , de Fine Olivarius F. , Dahlstrom K. , Wulf H. C.
Published: October 2006

Background/aims: The sensitivity of human skin to UV radiation is investigated by visual grading of the resulting erythema reactions 24 h after exposure to a series of increasing UV doses. Visual erythema assessment is, however, subjective and depends on pigmentation and redness of the adjacent un‐irradiated skin and can be aided by skin reflectance spectroscopy and laser Doppler blood flow measurements. Erythema is accompanied by a raised skin temperature, and this reaction might be utilised as a simple objective measurement of UV sensitivity.

Methods: Sixteen patients with cutaneous malignant melanoma, 16 patients with basal cell carcinoma, and 36 healthy people were phototested with simulated sunlight on previously UV un‐exposed buttock skin. The resulting erythema reactions were graded visually 20‐24 h post‐exposure and measured by skin reflectance spectroscopy and laser Doppler flowmetry, and the surface skin temperature was determined in the erythema reactions and in adjacent un‐irradiated skin by a contact thermometer.

Results: Skin surface temperature in UV‐induced erythema reactions was dose dependent, was statistically identical in skin cancer patients and in healthy people, and was age independent. The average temperature increase in barely perceptible erythema was 0.7°C (SD=1.1°C), and in bright red erythema it was 3.5°C (SD=2.0°C). Skin surface temperature increases were correlated to measurements by skin reflectance spectroscopy and by laser Doppler flowmetry.

Conclusions: Skin surface temperature changes can be used as a simple objective measurement of UV sensitivity in healthy people and in skin cancer patients and may be particularly useful in heavily pigmented people where visual assessment of erythema is difficult or impossible.
Magnetic resonance chemical shift microimaging of aging human skin in vivo: initial findings
Authors: Wright A. C. , Bohning D. E. , Pecheny A. P. , Spicer K. M.
Published: October 2006

Background/aims: In recent decades, interest has increased in the chronological and environmental factors governing the aging of skin. Various methods have been used for determining water and lipid content of human skin as a function of subject age. Magnetic resonance chemical shift imaging (CSI) offers a noninvasive technique for observing detailed distributions of water, lipids and other chemicals in the skin, and thus may be useful in dermatogerontology.

Methods: Human skin was examined in vivo on nine healthy volunteers, both male and female. Localized 1H spectra of the skin were obtained from voxels 78 μm thick and parallel to the skin surface. Unique water and lipid profiles were observed for different individuals, showing the composition and microstructure of epidermis, dermis and hypodermis in each subject. These allowed the quantification of skin thickness in vivo by the first appearance of triacylglyceride olefinic protons at the dermal‐hy‐podermal junction, or alternatively by the degree of lipid infiltration into dermis.

Results: The relative concentration of free water in the skin, normalized to skin thickness, was observed to be slightly greater in older subjects and also in tanned subjects. More significantly, a microstructural feature common to every subject, i.e., the position of a possible capillary plexus in the dermis, showed migration toward the skin surface with advancing age.

Conclusions: Such observations are consistent with previous studies of skin aging by other techniques and show promise for CSI in dermatogerontology as a non‐invasive means for determination of skin water in vivo.
A 31P NMR study of extracted phospholipid composition of human skin: full thickness skin, dermis, epidermis and granulation tissue
Authors: Meneses Patricio , Crane Julie M. , Ennis William J.
Published: October 2006

Background/aims: Phospholipids are the most important component of the plasma membrane in skin cells. Until recently, skin phospholipids have only been studied by chromatography and those results need confirmation by other methods such as 31PNMR spectroscopy.

Methods: Phospholipid profiles were analyzed from human skin and granulation tissue using 31PNMR spectroscopy. Skin samples were taken from lower extremity amputation specimens and from one healthy volunteer. The granulation tissue was obtained from the wound bed of venous stasis ulcers, pressure ulcers and post‐op non‐healing surgical wounds. Phospholipid extractions were performed on full thickness skin samples (excluding the subcutaneous layer), epidermis, dermis, and granulation tissue biopsies.

Results: Twelve phospholipid species were detected in each of the groups studied: PA, CL, DHSM, Eplas, PE, PS, SM, LPC, PI, AAPC, and PC. Statistically significant differences were found between epidermis and full thickness skin in relation to the quantity of PA, CL, DHSM, LPC, AAPC, and PC. The phospholipid ratio [(PE+Eplas+PI+PA)/PC] was calculated for each group: the epidermis value was 1.30, the dermis value was 0.62 and full thickness skin value was 0.49.

Conclusions: These phospholipid profiles present a very unique distribution, which correlates with the physiological activity of the individual layer. The study of the phospholipid profile of granulation tissue opens a new line of research, evaluating changes in these profiles during the various phases of wound healing.
Elastotic degenerative change and yellowish discolouration in photoaged skin
Authors: Nishimori Y. , Pearse A. D. , Edwards C. , Marks R.
Published: October 2006

Background/aims: One clinical sign of photodamage is a sallow discolouration of the skin, and solar elastotic degenerative change in the upper dermis may cause this change. We have attempted to quantify these phenomena and relate them to each other and to age.

Methods: Twenty‐seven healthy volunteers (age 18 to 61 years) were recruited. We examined the back of the hand of photodamaged individuals and the inner upper arm to demonstrate changes due to ageing. Each site was assessed for cutaneous blood flux using a laser Doppler fluxmeter (PF4000, Perimed UK), and for melanin pigmentation using a Melanin Index meter (Dermotronics Ltd, Cardiff, UK). Skin colour was measured using a diode array spectrophotometer (MCPD‐1000, Photal, Japan), which computes CIE coordinates L*, a*, b*. Biopsies from each site were obtained from 13 of the subjects and were processed and stained with Gomori's aldehyde fuchsin. The percentage area of elastic staining material in the dermis was measured using image analysis. Sections were measured in four bands of 200 micron depth, and four fields were measured per band.

Results: Neither melanin content nor skin blood flux correlated with age for either skin site. Percentage area of elastosis correlated with age on the exposed site from the uppermost 600 microns of the dermis, (<200 micron depth, r=0.74, P<0.01, 200<depth<400, r=0.57, P<0.05; 400<depth<600, r=0.57, P<0.05). No correlation was found on the unexposed inner upper arm site. On the back of hand site, a linear relationship was found between a parameter derived from the L*, a*, b* coordinates of (b*‐5a*) and both age (r=0.904, P<0.001) and percentage area of elastosis of the uppermost 200 microns of dermis (r=0.74, P<0.01). This was not seen for the inner upper arm site. On exposed sites, the coefficient (b*‐5a*) correlates with solar elastosis and these both correlate with age, which is related to exposure.

Conclusion: This data confirms that solar elastosis accounts for the yellowish discolouration of sun damaged skin, and suggests that the coefficient b*‐5a* could be used for the non‐invasive quantification of solar elastosis.
The plastic sing effect of moisturizers on human skin in vivo: a measure of moisturizing potency?
Authors: Jemec Gregor B. E. , Wulf Hans Christian
Published: October 2006

Background/aims: Moisturisers have many different effects on the skin, but increased plasticity is an important effect of moisturising. We have studied the short‐term effects of six commonly used brands of moisturisers on the plasticity of normal and atopic skin.

Methods: Measurements of skin mechanics and capacitance were made in 25 healthy volunteers and 15 patients with atopic dermatitis, before and after moisturiser application.

Results: Baseline mechanical values did not differ in the two groups. Capacitance was significantly lower in atopics (P<0.001). All moisturisers increased distensibility and hysteresis of normal as well as atopic skin. Vaseline® and Locobase® caused significantly greater distensibility increases than other moisturisers tested in normal skin, and Vaseline® caused a significantly greater increase in the hysteresis of normal skin. Hysteresis was unaffected by Kerodex®and Clinique® in normal skin. No differences were seen between the effects of different moisturisers in atopic skin. Capacitance measurements fell significantly in normal skin, possibly because of residual cream on the skin surface, while an increase or a significantly smaller reduction were seen in atopic skin. This may reflect better absorption of the moisturisers in atopic skin.

Conclusions: The results suggest that high lipid moisturisers cause significantly greater changes in plasticity of normal skin than low‐lipid moisturisers, and that atopic skin is influenced to a higher degree by moisturisers than normal skin.
Biomechanical properties of scalp flaps and their correlations to reconstructive and aesthetic surgery procedures
Authors: Raposio Edoardo , Nordström Rolf E. A.
Published: October 2006

Background/aims: In formulating an accurate pre‐operative plan when performing plastic surgery, the biomechanical properties of the soft‐tissues involved should always be taken into account. No study has yet been carried out regarding the tensiometric peculiarities of the human scalp. The aim of the present study was to measure the load‐elongation properties of the human scalp, in an attempt to characterize it through the constants of a stress‐strain theory. This would provide plastic surgeons with information needed to test the soundness of the various surgical techniques currently adopted, as well as a way to better plan a reconstructive or aesthetic procedure on the scalp.

Methods: Data were collected by stepwise loading 20 scalp flaps, obtained by a reversed‐Y scalp incision down to and through the galea aponeurotica, together with 1 ‐cm undermining, on the subgaleal layer, along both sides of the sagittal scalp incision.

Results: The tissue's stress response to displacement was visualized as a three‐phase characteristic. Initially linear (load range: 0 to 500 g), the scalp's compliance gradually reduced (load range: 500 to 1500 g) and eventually demonstrated an exponential stress‐strain characteristic of rapidly increasing stiffness (load range: 1500 to 5000 g). Young's modulus E was derived from the mean‐values curve, and was found to be equal to 117.1 g/ mm.

Conclusions: These data have practical implication for studying the effects of complex surgical closures on the one‐dimensional stress distribution of the scalp, while allowing the use of analytical methods to predict the consequences of closure design in various plastic surgery procedures on the scalp.
Characterization of sulfur mustard vapor‐induced cutaneous lesions on haired guinea pigs*
Authors: Braue E. H. , Nails C. R. , Way R. A. , Zallnick J. E. , Rieder R. G. , Lee R. B. , Mitcheltree L. W.
Published: October 2006

Background/aims: Sulfur mustard (2,2′‐dichlorodiethyl sulfide, HD) is a potent vesicating (blistering) agent. In this report, we describe the time‐course and the dose‐dependent response following cutaneous exposure to sulfur mustard (HD) in the haired guinea pig model. The purpose of this study was to evaluate the usefulness of the haired guinea pig as a vesicant research model.

Methods: Seventy‐two animals were divided into nine groups of eight animals each. Hair on the dorsal side of each animal was removed by clipping with an electric clipper followed by application of a chemical depilating agent (MAGIC Shaving Powder). Six dorsal skin sites on each animal of a given group were exposed to saturated HD vapor (1.4 mg/l) for one of nine exposure times between 0‐8 min. Lesions were evaluated for erythema (reflectance colorimeter) and edema (ultrasound imaging) at 4, 6, 12, and 24 h postexposure. Damage at the dermal‐epidermal junction (DEJ) was evaluated by histopathology at 24 h postexposure.

Results: We observed that the hair removal process was time‐consuming, produced significant initial erythema, and resulted in increased dorsal skin sensitivity to low HD exposure levels. The time‐course of exposure response to HD was observed to be dose‐dependent and similar to the hairless guinea pig model.

Conclusions: The haired guinea pig is inferior to the hairless guinea pig as a vesicant model due to the complications resulting from the hair removal process. However, the haired guinea pig is a useful model for evaluating the cutaneous effects of HD vapor and can be developed into a routine screening tool for the evaluation of topical barriers against HD vapor exposure.
Image analysis of the distribution of turnover rate in the stratum corneum
Authors: Hayashi Shoji , Matsue Kohji , Takiwaki Hirotsugu
Published: October 2006

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.
3‐D profilometer using a CCD linear image sensor: application to skin surface topography measurement
Authors: Nita D. , Mignot J. , Chuard M. , Sofa M.
Published: October 2006

Background/aims: Measurement of cutaneous surface topography can be made by three‐dimensional (3‐D) profilometry. Different equipment is used for this measurement. The magnitude of the vertical scale required, which can vary from several tens of micrometers (microrelief) to several millimeters (skin pathologies), depends also on the precision required and the duration of acquisition time. Over the last few years, different apparatuses have been produced, with a vertical range that is most frequently used for classical industrial applications, i.e., 0‐1000 μm.

Methods: The system developed here has a wide range of about 7 mm and is accurate enough to analyse each of the different skin surfaces that fall in this range without changing magnification. An optical principle, operating without any contact with a skin replica, allows a precise measurement with a high scanning speed.

Results: The profilometer has a vertical sensitivity of 4 μm within a vertical range of 7 mm. This sensitivity is lower than that of a mechanical or focusing profilometer, but the vertical range is wider.

Conclusions: The system has several advantages: because of its verticale range, it can measure large surfaces with great roughness variations; the initial position of the replica beneath the profilometer must be within the 7 mm vertical range; and skin topography can be quantified, without contact, in a short time.
Basal transepidermal water loss: right/left forearm difference and motoric dominance
Authors: Rodrigues Luis , Pereira Luis Marcelo
Published: October 2006

Background/alms: Evaporimetry and transepidermal water loss (TEWL) evaluations are among the most important means of approaching basic cutaneous physiology in terms of its epidermal barrier function. However, physiological skin complexity, together with the loose specifications currently available for analytical purposes, justify the need for further investigating and identifying eventual covariates and limiting factors with respect to both the epidermal barrier function issue and evaporimetry itself.

Methods: The relevant operating procedures were investigated with respect to the anatomical and functional equivalence of contralateral sites as they are often used in TEWL determinations and topically applied substance efficacy testing. The study was conducted on human volunteers using five different sites in both forearms, using a standard evaporimetry apparatus. Special attention was put on the right/left forearm difference regarding normal daily life motoric dominance reported by each individual.

Results: A consistent difference between TEWL values measured at the most active arm was detected when compared with the readings from the opposite limb. Also, those sites placed nearer the extremities of the forearm behave differently from the inner ones.

Conclusions: All information thus gathered suggests that using contralateral sites in study protocols for TEWL determinations, particularly when one side is intended to act as control, requires awareness with respect to the physiological and functional differences of the sampling sites chosen. In any case, a proper randomisation and balancing of the experimental design is crucial.
Electrical conductance: a controversial parameter in the evaluation of emollients in atopic dermatitis
Authors: Ferreira Maria João , Fiadeiro Teresa , Silva Marília , Soares António Pinto
Published: October 2006

Background/aims: Essential fatty acids are important in maintaining skin function and their deficiency is associated with scali‐ness and increased transepidermal water loss (TEWL). This can be one of the pathogenic processes implicated in atopic dermatitis (AD). Several studies have assessed the value of essential fatty acid‐enriched diets in AD but the benefits of topical γ‐lino‐lenic acid (GLA) therapy have been less well evaluated. The aims of this study were: a) to compare the effects of GLA‐con‐taining emollients and classical emollients, regarding clinical benefits, cutaneous hydration (by a conductance method) and TEWL; b) to assess the clinical relevance of these two biomet‐rical methods (conductance and TEWL).

Methods: Twenty‐three AD children were randomised into four groups, to compare three emollients containing GLA in different concentrations and one classical emollient. They were evaluated in eight visits for 12 weeks, using a clinical score and measurements of TEWL with the Tewameter™ and of cutaneous hydration with the Nova™.

Results: Kruskal‐Wallis statistical analysis showed significant differences in cutaneous hydration (P<0.05) between each of the three treatment groups and the control group. TEWL and clinical scores did not show statistically significant differences. During the study no children from the GLA groups developed eczematous lesions versus two children from the non‐GLA group.

Conclusions: Discrepancies between conductance and TEWL measurements may represent false positive results of the former method due to electrical phenomena related to polarity of the GLA molecule or of other elements in the formulations. However, some differences in clinical evolution between the GLA and non‐GLA groups require further studies to assess the possible additional benefits of topical emollients containing GLA.
Investigation of biochemical changes in skin layers by NMR microscopy
Authors: Lee D. H. , Kim J. I. , Lee H. K.
Published: October 2006

Background/aims:Biochemical changes occurring in epidermis are hardly visible on a conventionally acquired magnetic resonance image. Objectives of the present study were to noninvasively visualize the biochemical changes in skin layers and to investigate the feasibility of dermal NMR microscopy.

Methods:1H NMR microscopy was utilized to investigate histological changes and/or skin pathology between normal skin and abnormal skin. Animal skin was used for both in vivo and in vitro investigations while human skin for the in vivo study.

Results:Relaxation times and diffusion information were found to be sensitive indicators of the biochemical changes arising from epidermis due to skin abnormality. Also, the swelling process of abnormal epidermis was monitored.

Conclusion:Dermal NMR microscopy was found useful for the study of the biochemical changes occurring in thin skin layers.
Ultrasound assessment of skin and wound tissue: comparison with histology
Authors: Rippon M. G. , Springett K. , Walmsley R. , Patrick K. , Millson S.
Published: October 2006

Background/aims: Ultrasound is a valuable technique in dermatological assessment as it is non‐invasive. This is particularly attractive for monitoring and evaluating wound healing. However, there is a limited literature on the use of ultrasound in monitoring wound healing.

Methods: In this study, the structures of skin (human and porcine) and healing wounds (porcine) were visualised using ultrasound (20 MHz) and compared with histology from the same site. Measurements of various features were undertaken using both ultrasound and histometric techniques and the results from each compared. Hydroxyproline levels were also measured and correlated with ultrasound measurement of granulation tissue.

Results: The echogenic characteristics of tissues are described. There was excellent correlation (r=0.96, P > 0.0001) between the ultrasound measurements and histology for porcine and human cadaver measurements. Ultrasound and histology measurements of acute porcine wounds also correlated well (r=0.96,P<0.0001). Comparison of hydroxyproline analysis with ultrasound measurements of fibrous granulation tissue (r=0.82,P > 0.001) indicates that ultrasound may be used to visualise accumulation of this tissue in wounds.

Conclusions: Ultrasonography has been shown to be a useful, reliable, quantifiable technique for the assessment of wound healing.
Use of Cutometer to assess dermal oedema in erysipelas of the lower legs
Authors: Dobrev H.
Published: October 2006

Background/aims: Inflammatory dermal oedema in erysipelas alters skin mechanics. The aims of this study were to determine the relationship between skin mechanical properties and changes in dermal water content in patients with erysipelas of the lower leg, and to assess the value of measuring skin elasticity in monitoring the effect of therapy.

Methods: Twenty‐five in‐patients were studied before treatment and after 10 and 20 days. Visual scoring of oedema, measurements of limb circumference and skin elasticity with a non‐invasive suction device (Cutometer) were made on the affected and unaffected lower legs.

Results: Indurated skin was characterized by raised delayed distension (Uv), final distension (Ut), resilient distension (R), viscoelastic to elastic ratio (Uv/Ue) and hysteresis (H) and lower immediate distension (Ue), immediate retraction (Ur), gross elasticity (Ua/Uf) and biological elasticity (Ur/Uf). The visual score of oedema and leg circumference significantly correlated with the increase in Uv Uv/Ue and H and the decrease in Ua/Uf and Ur/Uf. The large 8 mm diameter measuring probe produced more pronounced changes than the small 2 mm probe. As a result of treatment, a significant reduction in viscoelastic parameters (Uv, Uv/Ue, R, H) and an increase in elastic parameters (Ua/Uf, Ur/Ut) were observed.

Conclusion: The non‐invasive method applied is suitable for objective assessment of dermal oedema and disease evolution in patients with erysipelas.
Corticosteroid skin atrophogenicity: assessment methods
Authors: Lee J. Y. , Maibach H. I.
Published: October 2006

Background/aims: Skin atrophy manifests itself as fragile and easily bruised skin, telangiectasia and striae distensae.

Methods: Various methods have been used to predict the atrophogenicity potential of topical corticosteroids in man. Assay standardization, including reference corticosteroid, anatomic site, method of administration, and quantification, has not been accomplished.

Results/Conclusion: This report reviews the literature and proposes a standard assay method.
Assessment of the atrophogenicity of corticosteroids to human skin using non‐invasive methods
Authors: Kolbe Ludger , Stoudemayer Tracy , Kligman Albert M.
Published: October 2006

Background/aims: Atrophy is the most common adverse effect of topical corticosteroids. The objective of this study was to determine whether atrophogenicity of a potent steroid could be demonstrated in a 3‐week period of open application using non‐invasive bioengineering methods.

Methods: Volar forearms were treated twice daily for 3 weeks with clobetasol propionate cream. The following methods were used: 1) B‐scan ultrasound; 2) Silflo‐replicas for microtopogra‐phy; 3) scanning electron microscopy; 4) Cutometer for bio‐mechanical assessments; 5) colorimetry for measuring skin color; 6) evaporimetry for transepidermal water loss; 7) polarized light photos; 8) sticky slides for corneocyte sizing; 9) D'Squames for estimating scaling; and 10) biopsies for histologic evaluation of atrophy

Results: After only 1 week, Silflo‐replica showed that glyphic patterns had been partially obliterated. At the same time, ultrasound scans showed dermal thinning, which increased over the 3‐week period. Extensibility by Cutometer decreased steadily during the treatment. Image analysis of ?Squames revealed an increase in scaliness. Evaporimetry showed an increase in trans‐epidermal water loss. Atrophy was confirmed by histology.

Conclusion: The use of non‐invasive bioengineering techniques provides a powerful tool to monitor atrophogenicity in a short period of open applications.