摘要:

The barrier properties of human epidermis grafted for 1–3 months onto nude mice are compared with normal human skin. Beside penetration studies with tritiated water and measurements of transepidermal water loss (TEWL), we analyzed the epidermal lipids by high-performance thin layer chromatography and evaluated the ultrastructure of the intercorneocyte lipid arrangement by freeze fracture electron microscopy (FFEM). The permeability of human skin for tritiated water and the TEWL exhibit no significant changes after grafting onto nude mice. FFEM analysis showed that grafted epidermis has the same morphological pattern as normal human epidermis. Regular desmosomes and lamellar lipid structures are present. Grafting did not qualitatively affect the lipid composition of human epidermis. Ceramides which contribute largely to the barrier function, have the same distribution profile.

ISSN:1660-5527    

DOI:10.1159/000211291

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The potential therapeutic activity of topically applied novel analogues of retinoic acid is currently measured in many different animal models. In most cases, the technique used is invasive and biopsy specimens are required. Furthermore, efficacy in these models is not a guarantee of success in treatment of humans. Therefore, predictive human pharmacology tests are required in order to quantify a retinoid effect on human skin before conducting large clinical trials. The aim of this study was to determine whether changes in corneocyte surface area could be used as a predictive measure for the efficacy of topical retinoids in man. Topical applications of all-trans retinoic acid gel (Aberel®), salicylic acid gel and the gel vehicle were made once daily for 4 weeks to skin of the lumbar region of healthy human volunteers. Corneocytes were recovered from these three treated zones as well as from one zone of untreated skin, and their surface areas were measured by image analysis using a MOP-Videoplan. The results showed that at no point during the 4 weeks of daily application to healthy human skin was there a statistically significant difference in the surface area of corneocytes recovered from Aberel, salicylic acid-, vehicle-treated or untreated sites. No specific effect of retinoic acid could be detected. However, although no between-treatment differences were found, significant cyclical changes in the mean surface areas with respect to baseline were observed.

ISSN:1660-5527    

DOI:10.1159/000211292

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

A cumulative dose-response curve of the effects of serotonin and its 5-HT2 receptor antagonist ketanserin in embryonic chick skin has been set up using morphological analysis and incorporation of 3H-thymidine as parameters. The resemblance between the results of the morphological analysis and those of the functional analysis was striking. From the results of these experiments, we could deduce new arguments in favor of the hypothesis that a 5-HT2 receptor is involved in the effects of serotonin and ketanserin in embryonic chick skin observed in vitro.

ISSN:1660-5527    

DOI:10.1159/000211293

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

An in vitro cell culture assay was developed to identify inhibitors of melanogenesis and agents which produce cytostatic or cytotoxic effects specifically in melanocytes. A total of 50 compounds related to tyrosine, dihydroxyphenylalanine, and hydroquinone (HQ) were tested in vitro in order to determine their effects upon a murine melanocyte cell line, Mel-Ab, that produces copious amounts of melanin in culture. The agents that demonstrated an inhibition of growth or pigment production by 50% (IC50) at < 100 μg/ml were considered active. The cytotoxicity of melanocyte-active compounds were also tested in vitro on a control nonmelanocyte cell line (HT 1080), using a simple crystal violet staining method to quantitate adherent cell number after treatment. The cell culture assay was validated with known potent melanocyte cytotoxic agents, including HQ and 4-S-cysteaminylphe-nol (4-S-CAP). Although most cytotoxic chemicals were nonspecific in this primary screen (i.e. killing both Mel-Ab and HT-1080 cells), several of the compounds tested exhibited high melanocyte-specific cytotoxicity, similar to HQ and 4-S-CAP. Potentially these compounds may be useful as either antimelanoma or skin depigmentation agents. All of the compounds identified as active in this primary screen were cytotoxic or cytostatic to melanocytes, except for the methyl ester of gentisic acid, which uniquely inhibited the de novo synthesis of melanin without cytotoxicity.

ISSN:1660-5527    

DOI:10.1159/000211294

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

In order to identify and characterize the sonographic variations between different age groups, 48 subjects, 24 aged 27–30, and 24 over 60, were studied with a 20-MHz B scanner on six skin sites. Images were evaluated by the instrument’s standard programme and by a new image analysis software package enabling the characterization of steady structures or transitory functional aspects of skin reactions, by highlighting areas in which the echo amplitudes are included within selected values, and by calculating their extension. Three bands were selected as intervals of interest, respectively, highlighting hyporeflecting parts of the dermis, tissue reflecting with intermediate amplitude values and hyperreflecting epidermis and dermis. This method was employed to assess skin thickness, demonstrating its decrease in elderly skin, to characterize and quantify the hypo-echogenic subepidermal band appearing in the elderly at volar and dorsal forearm skin, and to evaluate echogenicity of the upper and lower dermis. Our data show that there is a great regional variation in the behaviour of ultrasound reflection of elderly skin in respect to the skin of young subjects. However, a general trend can be identified, consisting in a shift from low-intensity ultrasound echoes, characteristic in the dermis of young subjects, to intermediate or high reflection amplitudes, which are more frequent in elderly skin. Thus, the echographic method provides two parameters for the evaluation of skin aging. Besides an accurate and early assessment of skin atrophy, it also enables an evaluation of physical properties of the skin, which do not influence the morphological aspect in microscopy, but induce variations of the acoustic behavior which are expressed by a modification ofthe reflectivity to ultrasound.

ISSN:1660-5527    

DOI:10.1159/000211295

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

In recent years magnetic resonance imaging has become a very efficient tool for in vivo quantification of water content and water behavior in living tissues. We have applied this technique to the study of the in vivo hydration profile in heel skin layers by quantification of the mobile water proton density versus depth. Effects of a bath, a moisturizer and repeated soaping are present. Hydration profiles by magnetic resonance imaging delineate two different structures in stratum corneum: an outer layer where hydration can be modified by external mechanisms and an inner layer where hydration is not altered. The main interest of this method lies in the fact that the physical signal is exactly located, as spatial encoding is the basis of in vivo imaging. This method differs from other noninvasive methods which acquire an averaged signal from a nondelimited volume of interest.

ISSN:1660-5527    

DOI:10.1159/000211296

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Two types of portable reflectance instruments, tristimulus colorimeters (Chroma Meter CR-200®) and narrow-band spectro-photometers (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.

ISSN:1660-5527    

DOI:10.1159/000211297

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

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.

ISSN:1660-5527    

DOI:10.1159/000211298

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

In this study, we investigated the effect of calcipotriol, prednicarbate and clobetasol 17-propionate on skin thickness over a treatment period of 6 weeks. The study was conducted as a controlled, randomized, double-blind comparison. The influence of these drugs on normal skin under occlusive conditions was assessed visually and by measuring skin thickness using 20 MHz B mode ultrasound. Both topically applied glucocorticosteroids lead to a significant decrease in skin thickness. In contrast to the glucocorticosteroid-induced atrophy, calcipotriol application on normal skin leads to an increase in skin thickness in all volunteers. The effect remains constant for the duration of treatment. The cause of this increase seems to be an irritative reaction of the skin which was histologically investigated in one volunteer. The histological features of this reaction are characteristic for a subacute dermatitis. The implications of these findings for the therapeutic mechanism of calcipotriol are discussed.

ISSN:1660-5527    

DOI:10.1159/000211299

出版商:S. Karger AG    

年代:1994

数据来源: Karger