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1.
Dry skin (xerosis) is a common dermatosis affecting people of varying skin types and ages and various areas of the body. It is associated with both skin thickening and skin thinning and is triggered by both exogenous (e.g. climate, environment, lifestyle) and endogenous (e.g. medication, hormone fluctuations, organ diseases) factors. Skin requires a water content of 10–15% to remain supple and intact. This water is either ‘static’ (i.e. bound) or ‘dynamic’. The predominance of hydrophobic substances in intercellular constituents is a means of regulating the humidity of the skin. Emollients, highly effective treatment adjuncts in the management of all dry skin disorders, help to restore damaged intercorneocyte lipid structures and increase the water content of the skin, helping to reduce scaling and improving its barrier function. 相似文献
2.
Tape stripping of human stratum corneum yields cell layers that originate from various depths because of furrows in the skin 总被引:2,自引:0,他引:2
R. G. van der Molen F. Spies J. M. van ‘t Noordende E. Boelsma A. M. Mommaas H. K. Koerten 《Archives of dermatological research》1997,289(9):514-518
Received: 21 November 1996 相似文献
3.
BACKGROUND: It is a common observation that superficial freezing of normal skin and skin tumors may create a transient superficial whitening effect. In this respect, cryoscopy refers to the direct observation by dermoscopy, with or without digital recording, of the visual alterations of the frozen tissues. AIMS: To define the optimal method of cryoscopy and to describe the cryoscopy patterns of normal skin and selected skin lesions. MATERIALS AND METHODS: The influence of (a) different cryogenic sources [solid carbon dioxide (-78.5 degrees C), liquid nitrogen (N(2), -196 degrees C), and a mixture of dimethyl ether and propane (-57 degrees C)], (b) various application methods (spraying, cotton chill tips, copper plate), and (c) freezing time was assessed with regard to clinical feasability, visualization quality, and persistance time of the whitening effect. Cryoscopy patterns of normal skin, callosities and of histologically proven seborrheic keratoses, verrucous hamartomas, molluscum contagiosum, keratoacanthomas, viral warts, condylomas, actinic keratoses, dermatofibromas, skin tags, basal cell carcinomas, angiomas, and melanocytic naevi were assessed. RESULTS: The cryoscopy images of skin highlighted the skin lines. They appeared similar regardless of the freezing source and the application method. The aspects differed according to the nature of the lesions. The cotton chill tip method provided a longer whitening period compared with the other cold sources, both in normal and lesional skin. Hence, it represented the most convenient way for performing digital recording cryoscopy. On normal skin, cryoapplication was limited to about 1.5 s due to pain, resulting in whitening times ranging from 6 to 9 s, which was too short for easy digital recording. On all studied skin tumors, a 10-s N(2) freezing time was not experienced as painful, and blanching time persisted for 20-34 s, allowing easy digital recording. The whitening time was longer with increasing freezing time on both normal and lesional skin. Every single examined normal skin site and all the skin lesions showed a strong whitening effect, except heavily cornified structures, including some keratoses, callosities, and viral warts. Increased contrast of the skin surface texture was observed in almost every studied lesion. CONCLUSION: The N(2) cotton chill tip technique appeared to be the most convenient technique for cryoscopy and provided longer whitening periods compared with the other freezing sources. Pain prevented its use on normal skin, but a series of exophytic skin lesions was conveniently accessible to cryoscopy. The differences in whitening periods of various epidermal components resulted in increased visual contrast, creating typical cryoscopy images for the different exophytic skin tumors. Cryoscopy represents a novel in vivo skin imaging technique that is rapid, non-invasive, cost-effective, and easily performed. It shows both investigative and diagnostic potentials. It is remarkable that cryoscopy pictures closely resemble those yielded by skin capacitance imaging. 相似文献
4.
Stratum corneum architecture, metabolic activity and interactivity with subjacent cell layers 总被引:3,自引:0,他引:3
Peter M. Elias 《Experimental dermatology》1996,5(4):191-201
5.
本文以正常人掌蹠角质层作抗原,应用酶联免疫吸附试验的方法,检测52名正常人和银屑病人血清中抗角质层抗体的含量,结果病人血清中抗角质层抗体的水平显著低于正常人(P<0.01),并且病人抗角质层抗体的消长变化与临床病情的进程和皮损的活动强度呈平行关系。 相似文献
6.
Purpose. This paper compares unsteady-state and steady-state methods for estimating dermal absorption or analyzing dermal absorption data. The unsteady-state method accounts for the larger absorption rates during short exposure times as well as the hydrophilic barrier which the viable epidermis presents to lipophilic chemicals.
Methods. Example calculations for dermal absorption from aqueous solutions are presented for five environmentally relevant chemicals with molecular weights between 50 and 410 and log10Kow between 0.91 and 6.8: chloromethane, chloroform, chlordane, 2,3,7,8-TCDD, and dibenz(a,h)anthracene. Also, the new method is used to evaluate experimental procedures and data analyses of in vivo and in vitro permeation measurements.
Results. In the five example cases, we show that the steady-state approach significantly underestimated the dermal absorption. Also, calculating permeability values from cumulative absorption data measured for exposure periods less than 18 times the stratum corneum lag time will overestimate the actual permeability.
Conclusions. In general, steady-state predictions of dermal absorption will underestimate dermal absorption predictions which consider unsteady-state conditions. Permeability values calculated from data sets which include unsteady-state data will be incorrect. Strategies for analyzing in vitro diffusion cell experiments and confirming steady state are described. 相似文献
7.
Hongbo Zhai Emi Dika Marina Goldovsky Howard I. Maibach 《Skin research and technology》2007,13(2):207-210
BACKGROUND/PURPOSE: If the occlusion time of a closed chamber evaporimeter on the skin is too long, saturation might occur. We previously compared an open chamber and a closed chamber device on healthy volunteers. Comparable data on stripped skin with higher evaporation rates are not available. This study compares the sensitivity and correlation of open and closed chamber devices in a tape-stripping human model. The amount of tape removed SC was also quantified with a protein assay method. METHODS: Ten healthy volunteers (six male and four female; seven Caucasians and three Asian; mean age 38+/-16) were enrolled. In a randomized manner, one forearm was measured by an open chamber device and the opposite by a closed chamber device. After recording baseline measurements, 20 strippings were taken on each test site with tape disks. Transepidermal water loss (TEWL) was measured at the end of 10 and 20 tape strippings at each test site. Stratum corneum (SC) aggregates in the strips was assayed. RESULTS: The mean values obtained from two devices were similar after 10 trips and 20 strips. There was no statistically significant difference. The closed chamber device showed a slightly higher (but not significant) inter-individual coefficient of variation. SC aggregates in the strips were similar and without a statistically significant difference. CONCLUSION: The study suggests that both devices might yield similar TEWL values on stripped human skin in vivo. 相似文献
8.
Mitsuhiro Denda Barbara E. Brown Peter M. Elias K. R. Feingold 《Archives of dermatological research》1997,289(2):104-110
Isoprenylation is the covalent attachment of isoprenyl groups, intermediates of the cholesterol biosynthesis pathway, to carboxy
terminal cysteine residues of proteins. Numerous proteins are isoprenylated including small GTP binding proteins, trimeric
G proteins, and nuclear lamins, and these prenylated proteins regulate a variety of cell functions, including cell growth,
cytokinesis, and differentiation. Here, we quantitated protein prenylation and determined which proteins are prenylated in
the epidermis of hairless mice by radiolabeling with
3
H-mevalonolactone following acute or chronic epidermal injury. In normal epidermis, four major radiolabeled bands, with molecular
weights of 17–26, 48, 54, and 68 kDa, were observed. The levels of each of these bands increased by 24–63% 16 h following
acute epidermal injury induced by topical acetone treatment or tape stripping, returning to normal by 24 h. On 2D gel electrophoresis,
there were no major differences between the patterns of labeling following barrier disruption. Subacute epidermal injury induced
by either acetone or tape stripping twice a day for 7 days and chronic injury induced by feeding an essential fatty acid-deficient
(EFAD) diet, also resulted in a significant increase in protein prenylation. As with acute injury, SDS-PAGE and 2D gel electrophoresis
did not reveal marked differences in the pattern of protein prenylation. These results demonstrate that the prenylation of
proteins in the epidermis is stimulated by injury, suggesting that one or more of these prenylated species may be important
in epidermal proliferation or differentiation.
Received: 29 May 1996 相似文献
9.
To probe age-related changes in skin barrier function, transepidermal water loss (TEWL) rates have been measured in young (19–42 years) and old (69–85 years) subjects. TEWL was determined at ventral forearm skin sites, which had been occluded for 24 hr with polypropylene chambers. Baseline TEWL rates (J
, which showed no dependence on age, were measured for each subject before and after the experiment. Following removal of the occlusive chamber, TEWL was monitored continuously from t = 0.5 min until its return to the baseline (preocclusion) level, which was typically in the range of 2–7 g/m2/hr. Initial TEWL rates (mean ± SD) were found to differ significantly between young (28.6 ± 7.5 g/m2/hr; n = 26) and old (36.9 ± 10.5 g/m2/hr; n = 18) subjects (P < 0.01). Relaxation of TEWL to J
was significantly slower in the aged cohort, such that the characteristic time for diffusion of water in the stratum corneum was estimated to be (mean ± SD) 176 ± 59 min for the young subjects, compared to 360 ± 76 min for the old (P < 0.001.). Thus, the initial TEWL value following removal of occlusion is significantly greater, and the excessive stratum corneum hydration produced by occlusion is dissipated more slowly, in old skin than in young. A hypothesis to explain the slower relaxation of perturbed TEWL in old skin is proposed. 相似文献
10.
M C Whitehead 《Neuroscience》1979,4(3):379-390
The consequences of depriving the optic tectum of axons from the contralateral eye have been studied in Golgi-impregnated brains from a staged series of chick embryos. Following enucleation at 2–5 days of age, measurements of dendritic length and the numbers of branches at all orders for three cell types were performed with an automated three-dimensional tracking system at various survival times. Dendritic lengths and the number of middle order branches of neurons from control animals, aged 12–14 days (stages 38–40), are greater than those from non-innervated embryos of the same ages. However, by Day 18 (stage 44), no significant differences in length or branching are seen between neurons from control and experimental embryos. Observations of these neurons revealed qualitative differences between experimental and control embryos. Growth cones, varicosities and filopodia, indicators of dendritic differentiation, are more commonly associated with neurons from control Day 12 and 14 embryos, than operated embryos of the same stages. However, at Days 16 and 18 these growth characteristics are more usually seen on neurons from deafferented embryos than from controls.The deleterious effects observed in experimental animals between Days 12 and 14 are presumably caused by the absence of optic fibers. The eventual growth during late embryogenesis, of the cells deprived of optic input, may reflect a trophic influence not acting in the earlier period. 相似文献