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PubMed2002

[The study for the hemodynamics of expansive skin and the transplant time of skin flap designed by expansive skin].

OBJECTIVE: To study the change rule of the hemodynamics of expanded skins and research the transplant time of random-pattern flaps that are made of the expanded skin. METHODS: 72 ears of 64 rabbits were used as a subject of experiment. Four items of the contrasted skin (n = 8) and expanded skin (n = 8 x 8), Which include the microvessel diameter, the microvessel density, the blood velocity and the blood volume, were observed and measured by the microcirculatory imaging computer analysis system, the enzyme histochemical dyeing and the more functions colored pathological imaging computer analysis system. The length -width proportion and the largest area of the flaps that had made of the expansive skin and survived were measured. RESULTS: (1) The four items of expanded skin, that the microvessel diameter, the microvessel density, the blood velocity and the blood volume are 13.43 +/- 0.98 micrometer, 0.0472 +/- 0.0022, 1012.70 +/- 65.51 micrometer/s, 14.71 +/- 0.74 micrometer(3)/s respectively, are much bigger or quicker than those of contrasted skin [(7.22 +/- 0.71) micrometer, 0.0108 +/- 0.0002, (327.01 +/- 65.51) micrometer/s, (1.46 +/- 0.41) micrometer(3)/s] and there is the significant difference between both (6.49 < t < 49.49, P < 0.01). (2) The blood velocity increases in the expanding phases and always keeps on higher level. The other items all change periodically. Span of the period is four weeks. The microvessel diameter and the blood volume have a peak value at third weekend of every period and in the later period enhance more on the basis of the former period. The microvessel density changes in definite range in every period. (3) The surviving area of the random skin flaps is the largest which were made of the expanded skin in third weekend of every period, it changes more than those of other weekends in same period and later period is superior to the former period. There is a significant difference compared with contrasted random skin flaps (q = 3.7215, P < 0.05; q = 5.5026, P < 0.01). CONCLUSION: The hemodynamics of the expanded skin changes periodically in expansive course. The time of peak value of the blood volume is the best opportunity that random-pattern skin flaps are made of the expanded skin in every period.

Animals↗
PubMed2002

Utility of MTT assay in three-dimensional cultured human skin model as an alternative for draize skin irritation test: approach using diffusion law of irritant in skin and toxicokinetics-toxicodynamics correlation.

PURPOSE: A cytotoxicity assay using a three-dimensional cultured human skin model, Living Skin Equivalent-high (LSE-high) was evaluated as an alternative to the Draize skin irritation tests using animals. A relation between the cytotoxicity and calculated concentration of an irritant in skin was also evaluated. METHODS: Colorimetric thiazoyl blue (MTT) conversion assay and a surfactant, cetylpyridinium chloride (CPC), were selected as a cytotoxicity assay and a model irritant. The fraction of dead cell number in the MTT assay or the Draize irritation score (in vitro and in vivo irritation data, respectively) was treated as a function of CPC concentration in the viable skin of LSE-high and guinea pig. Separately, in vitro permeations of CPC through the LSE-high or excised guinea pig skin were determined to calculate the average concentration of CPC in the viable skin using the Fickian diffusion theory. The obtained relations between the irritation scores and CPC concentration were evaluated by the Emax model (Hill equation). RESULTS: CPC concentration showing 50% irritation (IC50) was similar for the MTT assay (18.9%) and Draize test (12.3%), and a good relationship (r = 0.981) was observed between the fraction of dead cell number and the Draize score. In contrast, IC50, 1.32%, for the MTT assay in LSE-high was much lower than that using guinea pig skin. We then corrected the results for the MTT assay using a ratio of IC50 in guinea pig skin against LSE-high, resulting in a good relation between both MTT results in guinea pig skin and LSE-high. CONCLUSION: The present results suggest that the MTT assay using LSE-high may be utilized as an alternative for the Draize test in animals for evaluating skin irritation.

Animals↗
PubMed2006

Kinetic analysis on the skin disposition of cytotoxicity as an index of skin irritation produced by cetylpyridinium chloride: comparison of in vitro data using a three-dimensional cultured human skin model with in vivo results in hairless mice.

PURPOSE: The aim of this study was to kinetically and dynamically analyze in vitro cytotoxicity as an index of skin irritation by use of a three-dimensional cultured human skin model and to compare the in vitro assay data with data from living animals. METHODS: A cationic surfactant, cetylpyridinium chloride (CPC), was selected as a model irritant. Living skin equivalent-high (LSE-high) and hairless mice were used for the in vitro and in vivo tests, respectively. Skin irritation dermatodynamics was evaluated by calorimetric thiazoyl blue (MTT) conversion assay both for in vitro and in vivo tests, whereas dermatokinetics of CPC in LSE-high and mouse skin were evaluated using HPLC. RESULTS: The time course of cell viability in the skin after application of CPC to intact skin was distinctly different from that of stratum-corneum-stripped skin in both LSE-high and hairless mice. Biphasic behavior characterized by two first-order rates with an inflection time point was observed in intact skin, whereas cell viability monoexponentially decreased immediately after CPC application in stripped skin. The time courses of cell viability in the skin and dermatodynamics were closely related to that of dermatokinetics of CPC. CONCLUSION: The present study demonstrates that the in vitro cytotoxic profile was similar to the in vivo cytotoxicity test and that dermatodynamics was related to dermatokinetics of CPC.

Algorithms↗
PubMed2000

Evaluation of dermal-epidermal skin equivalents ('composite-skin') of human keratinocytes in a collagen-glycosaminoglycan matrix(Integra artificial skin).

Integra artificial skin (Integra LifeSciences Corp., Plainsboro, NJ, USA) is a dermal template consisting of bovine collagen, chondroitin-6-sulphate and a silastic membrane manufactured as Integra. This product has gained widespread use in the clinical treatment of third degree burn wounds and full thickness skin defects of different aetiologies. The product was designed to significantly reduce the time needed to achieve final wound closure in the treatment of major burn wounds, to optimise the sparse autologous donor skin resources and to improve the durable mechanical quality of the skin substitute. The clinical procedure requires two stages. The first step creates a self neodermis, the second creates a self epidermis on the neodermis. However, it is desirable to cover major burn wounds early in a single step by a skin substitute consisting of a dermal equivalent seeded in vitro with autologous keratinocytes ('composite-skin') out of which a full thickness skin develops in vivo.The goal of this experimental study was to develop a method to integrate human keratinocytes in homogeneous distribution and depth into Integra Artificial Skin. The seeded cell-matrix composites were grafted onto athymic mice in order to evaluate their potential to reconstitute a human epidermis in vivo. We were able to demonstrate that the inoculated human keratinocytes reproducibly displayed a homogeneous pattern of distribution, adherence, proliferation and confluence. The cell-matrix composites grafted in this model exhibited good wound adherence, complete healing, minor wound contraction and had the potential to reconstitute an elastic, functional and durable human skin. Histologically we were able to show that the inoculated human keratinocytes in vivo colonised the matrix in a histomorphologically characteristic epidermal pattern (keratomorula, keratinocyte bubbling) and developed a persisting, stratified, keratinising epidermis which immunohistologically proved to be of human origin. These experimental results demonstrate the establishment of an effective cell cultivation process which may be suitable for scale-up production of the epidermal component as large-scale composite-skin grafts. When seeded into Integratrade mark and grafted onto the nude mouse a replacement skin with normal functioning dermal-epidermal components was developed. These results encourage the design of a clinical trial to assess the function of this composite graft in man.

Animals↗
PubMed2005

Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin.

Magnesium salts, the prevalent minerals in Dead Sea water, are known to exhibit favorable effects in inflammatory diseases. We examined the efficacy of bathing atopic subjects in a salt rich in magnesium chloride from deep layers of the Dead Sea (Mavena(R) Dermaline Mg(46) Dead Sea salt, Mavena AG, Belp, Switzerland). Volunteers with atopic dry skin submerged one forearm for 15 min in a bath solution containing 5% Dead Sea salt. The second arm was submerged in tap water as control. Before the study and at weeks 1-6, transepidermal water loss (TEWL), skin hydration, skin roughness, and skin redness were determined. We found one subgroup with a normal and one subgroup with an elevated TEWL before the study. Bathing in the Dead Sea salt solution significantly improved skin barrier function compared with the tap water-treated control forearm in the subgroup with elevated basal TEWL. Skin hydration was enhanced on the forearm treated with the Dead Sea salt in each group, which means the treatment moisturized the skin. Skin roughness and redness of the skin as a marker for inflammation were significantly reduced after bathing in the salt solution. This demonstrates that bathing in the salt solution was well tolerated, improved skin barrier function, enhanced stratum corneum hydration, and reduced skin roughness and inflammation. We suggest that the favorable effects of bathing in the Dead Sea salt solution are most likely related to the high magnesium content. Magnesium salts are known to bind water, influence epidermal proliferation and differentiation, and enhance permeability barrier repair.

Administration, Cutaneous↗
PubMed1998

Time-dependent variations of the skin barrier function in humans: transepidermal water loss, stratum corneum hydration, skin surface pH, and skin temperature.

Although circadian rhythms have been described for many human functions, there are minimal data on circadian rhythms related to skin physiology. This study investigated the circadian rhythmicity of skin variables related to skin barrier function in humans. We measured transepidermal water loss, stratum corneum moisture, skin surface pH, and skin temperature in 16 healthy volunteers (nine men and seven women, aged 23-53 y). Subjects were sampled every 2 h in two sessions over a 24 h span. Twelve samples were obtained for each variable in the following sites: forehead, forearm, upper back, and shin. We used cosinor analysis and ANOVA to validate observed differences. Time-dependent rhythms were detected in most skin variables except in stratum corneum hydration. We found a statistically significant circadian rhythmicity characterized by cosinor analysis in transepidermal water loss, skin surface pH, and skin temperature on the forearm, forehead, and shin. Peak-trough differences occurred in all locations. The values of the same variables measured at different sites correlated positively, whereas the values of the different variables did not. These results suggest that skin permeability is higher in the evening and night than in the morning. These data may be clinically relevant in several aspects applied to skin physiology and topical drug application.

Adult↗
PubMed2005

An allogeneic cultured dermal substitute suitable for treating intractable skin ulcers and large skin defects prior to autologous skin grafting: three case reports.

Intractable skin ulcers that arise as secondary lesions from disease and full-thickness skin defects that result from skin tumor excision often need autologous skin grafting to close the wound. We developed an allogeneic cultured dermal substitute (CDS) to shorten the time needed to prepare a wound bed suitable for autologous skin grafting. The CDS was prepared by plating normal human fibroblasts on a spongy matrix consisting of hyaluronic acid and atelo-collagen. The allogeneic CDS was then placed on the rinsed wound surface. This procedure was repeated twice a week for up to five weeks, until the wounds were closed by autologous skin grafting. In all three cases, after CDS treatment for two to five weeks, the wound conditions became suitable for skin grafting; these conditions had not been improved by conventional topical treatments, including topical basic fibroblast growth factor (bFGF). Healthy granulation tissue developed rapidly, concomitant with wound size reduction. The present results indicate that CDS is an excellent biological wound dressing for improving wound conditions so that they are suitable for subsequent autologous skin grafting as well as for shortening the treatment duration for skin ulcers and full-thickness skin defects.

Aged↗
PubMed2000

Skin surface pH, stratum corneum hydration, trans-epidermal water loss and skin roughness related to atopic eczema and skin dryness in a population of primary school children.

Non-invasive investigations of skin morphology and function are standard tools to study the pathophysiology of several cutaneous disorders, yet they have not been used in population-based epidemiological studies. Here we examined skin surface pH, stratum corneum hydration, trans-epidermal water loss (TEWL) and skin roughness by profilometry in a study population comprising 377 primary school children (8-9 years old) as part of a multicentre survey on risk factors for allergic diseases in school children. Skin surface pH showed significant higher values (p=0.029) in the group with atopic eczema (n=45) compared with the group without atopic eczema; all other parameters did not differ significantly between children with and without atopic eczema. With increasing skin dryness there was a significant increase in pH values (p=0.004). Stratum corneum hydration showed a significant decrease with increasing dryness (p<0.001). Measurement of skin roughness also revealed a significant linear relationship with skin dryness (p=0.02). It is concluded that measurement of skin surface pH, corneometry and profilometry are useful non-invasive techniques to objectively assess skin dryness in epidemiological studies regarding atopic skin disease.

Body Water↗
PubMedDate not supplied

Changes in the skin moisture contents, skin color, and skin protein conformational structures of sprague-dawley rats after ultraviolet B irradiation.

The influence of ultraviolet B (UVB) irradiation on the skin moisture contents, skin color, and protein secondary structure in the skin of alive Sprague-Dawley (SD) rats was investigated. The UVB irradiation source emitted 725 +/- 10 microW/cm(2) of UVB range with a peak at 302 nm during the exposure course of 6 h/day for 3 successive days. The moisture content of SD rat's skin first decreased with the UVB irradiation, then returned to normal level on days 1 and 2, and, finally, decreased significantly with the increase of UVB irradiation on day 3. After the 6-hour irradiation on days 1 and 2, the moisture contents of the irradiated skin of SD rat returned to normal values, suggesting repairability of the irradiated skin of SD rat during the following 18 hour period without irradiation. By increasing frequency and duration of UVB irradiation, the skin color parameters exhibited a lower L* value, a greater a* value, and a higher DeltaE value, indicating that the skin color darkened and reddened. The slight modification of protein secondary structure of the skin of SD rats after repeated UVB irradiation was evidenced. However, the infrared spectrum during the initial course of irradiation, from day 1 to day 3, exhibited a similar pattern. Thus, the alive SD rat's skin was repairable during the 18-hour period without irradiation.

Animals↗
PubMed1997

[Thin split thickness skin grafting double taken from avulsed skin in treatment for skin avulsion in children].

In order to utilize avulsed skin to cover skin defects, a new skin grafting technique, thin split thickness skin grafting double taken from avulsed skin, was used in 23 cases of severe skin avulsion. The skin grafts in profound layer were observed histologically. The results showed no difference between skin grafts in superficial layer and ones in profound layer, but the latter needed longer time to heal. Using this technique, we can obtain skin graft in double amount from avulsed skin.

Adolescent↗
PubMed1994

A retinoic acid-inducible skin-specific gene (RIS-1/psoriasin): molecular cloning and analysis of gene expression in human skin in vivo and cultured skin cells in vitro.

A retinoic acid (RA) inducible skin-specific gene transcript (RIS-1) was isolated by differential hybridization screening of a RA-treated human skin cDNA library. The library was constructed from pooled RNA derived from normal adult human skin treated with all trans-RA for 4 h (n = 6) and 12 h (n = 6) in vivo. RIS-1 cDNA corresponded to a 0.6 kb transcript that was barely detectable in normal adult human skin but was significantly induced by 8 h in RA-treated compared to vehicle-treated skin (range 1.1-3.6 fold). Prolonged RA treatment for up to 24 h further increased relative RIS-1 mRNA levels by 1.3-5.5 fold. HPLC analysis of the RA content of 0.1% RA-treated skin in vivo revealed significant levels at 6 h (18.8-120.6 ng RA/g wet weight tissue; approximately 240 nM), immediately preceding the time point at which the increased RIS-1 mRNA level was first seen. This concentration of RA also induced the mRNA levels for cellular RA binding protein II (1.6-19 fold), a marker of RA activity in human skin. RIS-1 mRNA was detected by Northern and dot blotting only in normal skin but not in any other normal human tissues examined, indicating a tissue-specific pattern of gene expression. RIS-1 transcripts were detected at very low levels in untreated cultured human epidermal keratinocytes, while no expression was seen in dermal fibroblasts and melanocytes, the other major cell types in skin. Southern analysis of human and mouse DNA indicated the existence of evolutionarily conserved sequences for RIS-1 between these two species. The polypeptide sequence derived from the partial RIS-1 cDNA was found to be identical to the calcium binding domain found in 'psoriasin', a gene whose expression appears to be increased in the skin of psoriasis patients.

Calcium-Binding Proteins↗
PubMed2006

Skin tolerance, efficacy, and quality of life of patients with red facial skin using a skin care regimen containing Licochalcone A.

BACKGROUND: Patients with rosacea and red facial skin often show sensitivity to skin care products which can exacerbate inflammation and subjective irritation. Besides pharmacologic management, special skin care is prudent to avoid cosmetically induced irritation and address cosmetic concerns. Appropriate skin care should provide gentle cleansing, UVA/UVB protection, effective moisturization, and concealing pigments to neutralize the appearance of redness. AIMS: To evaluate skin compatibility and efficacy of a skin care regimen containing licochalcone A (Lic A), an anti-irritant from the licorice plant Glycyrrhiza inflata, for subjects with mild to moderate facial redness. PATIENTS/METHODS: Sixty-two patients with mild to moderate red facial skin used a four-product skin care regimen for 8 weeks. Clinical assessments of erythema and subjective irritation, cross-polarized photography, and self-assessment questionnaires were completed at baseline, and after 4 and 8 weeks of use. A quality of life questionnaire was given at baseline and week 8. RESULTS: Clinical evaluations, subject response, and photography confirmed very good tolerability of the regimen and effective neutralization of redness by the pigmented products. Significant improvements in average erythema scores were observed at 4 and 8 weeks (P < 0.05), and an improvement in quality of life was confirmed by the patient questionnaires. DISCUSSION: The skin care regimen containing Lic A was found to be compatible with the sensitive facial skin of patients with rosacea and improved the appearance of persistent facial redness. The products were also observed to be compatible with daily metronidazole treatment.

Adult↗
PubMed2006

[Bovine udder skin (BUS): testing of skin compatibility and skin protection].

New concepts of the horny layer as a metabolically active part of the epidermal permeability barrier elicited a re-evaluation of conventional mechanisms of occupational skin protection. Both skin protection products and noxae must penetrate the horny layer of the skin to be effective. The isolated perfused bovine udder skin (BUS) model reflects the natural penetration pattern; hence skin irritation, penetration and absorption can be investigated simultaneously. Using whole skin biopsies the degree of irritation in untreated (control), treated and pre-treated skin is measured by assessing the irritancy (PGE2-concentration) and cytotoxicity (MTT assay) after the exposure period of 0.5 h, 1.0 h and 5.0 h. Two types of skin protection studies were reported. One was a laboratory study using the water-soluble sodiumlaurylsulphate (10%, 15%) as noxa. The other study was initiated by a severely skin irritating water-soluble coolant (approx. 5%). This well documented case occurred in a metal working plant. In both studies different degrees of protective potential against the model noxae SLS and the coolant could be observed.

Animal Testing Alternatives↗
PubMed1993

The autoimmune blistering skin disease bullous pemphigoid. The presence of plasmin/alpha 2-antiplasmin complexes in skin blister fluid indicates plasmin generation in lesional skin.

Plasminogen activators produced locally in the skin have been implicated in blistering skin diseases. To explore whether plasminogen activators convert their substrate plasminogen into plasmin locally in the lesional skin we have analyzed the autoimmune blistering skin disease bullous pemphigoid. Enzyme activity was detected in bullous pemphigoid skin blister fluid by using a low molecular weight chromogenic substrate for plasmin. Enzyme activity was detected neither in suction blister fluid raised on normal skin nor in normal plasma. Immunoprecipitation or fractionation by molecular sieve chromatography of bullous pemphigoid skin blister fluid followed by testing in immunoassays disclosed putative plasmin/alpha 2-macroglobulin complexes and plasmin/alpha 2-antiplasmin complexes. Enzyme activity detected in bullous pemphigoid skin blister fluid by the low molecular weight chromogenic peptide assay was ascribed to the putative plasmin pha 2-macroglobulin complexes. Because formation of plasmin-inhibitor complexes requires the active plasmin, our findings indicate previous activation of plasminogen to plasmin in skin lesions. There was no evidence for free plasmin (i.e., plasmin not complexed to inhibitors) in bullous pemphigoid blister fluid, suction blister fluid, or plasma.

Amino Acid Sequence↗
PubMed2000

Can dog-ear formation be decreased when an S-shaped skin resection is used instead of a spindle skin resection? A three-dimensional analysis of skin surgery techniques using the finite element method.

Dog-ear formation is often unavoidable with resection and suturing of the skin, including spindle excision. Regarding dog-ear formation after basic spindle skin resection during removal of a round tumor of the skin, we quantitatively analyzed the frequency of dog-ear formation with respect to the following three techniques: previous spindle skin resection, S-shaped skin resection, which has been experientially considered to induce limited deformity, and mosque-shaped skin resection for control. To date, by using paper models or sponges, various techniques of skin resection have been simulated in the field of plastic surgery. In the present study, we performed three-dimensional simulation and analyzed three different techniques of skin resection by using the finite element method. As a result, image simulation demonstrated that the frequency of dog-ear formation was limited by S-shaped, spindle, and mosque-shaped skin resection, in descending order.

Computer Simulation↗
PubMed1988

The water barrier function of the skin in relation to the water content of stratum corneum, pH and skin lipids. The effect of alkaline soap and syndet on dry skin in elderly, non-atopic patients.

Clinical dryness of the skin is a common problem among elderly, dermatological patients. In the present investigation, hydration, surface lipids, skin pH and water barrier function as expressed by the transepidermal water loss (TEWL) were studied in both dry and normal skin. Using these parameters, a comparison of the local effects of acid and alkaline cleansing products was made. In non-atopic elderly patients with dry skin, the TEWL values were lower than in the younger control group but higher than in the older controls. Following one week's topical therapy, the TEWL values in the patient group decreased further and approached the lower values of the older control group. At the same time the skin hydration values increased, indicating a beneficial effect on the skin barrier. An inverse relationship was demonstrated between TEWL and skin hydration. The study indicates that high TEWL values are frequently correlated with high pH, low hydration of the stratum corneum and reduced skin surface lipid content. Despite the intensive use of an acid syndet and lotion, the pH-readings increased but were still within the 'confidence limits' of the control groups.

Administration, Cutaneous↗
PubMed1991

Keratohyalin granules are heterogeneous in ridged and non-ridged human skin: evidence from anti-filaggrin immunogold labelling of normal skin and skin of autosomal dominant ichthyosis vulgaris patients.

Recent biochemical and morphological investigations have provided evidence for a heterogeneous composition of keratohyalin in human skin. A major component is filaggrin. In interfollicular epidermis the heterogeneity of keratohyalin is not directly visible, whereas in normal ridged skin bicomponent keratohyalin is revealed by electron microscopy. Skin biopsies of ridged and non-ridged skin of normal individuals and patients with autosomal dominant ichthyosis vulgaris (ADI)--characterized by defective keratohyalin synthesis and lack of filaggrin--were investigated by routine transmission electron microscopy and immunogold postembedding techniques using a commercial monoclonal anti-filaggrin antibody. In normal interfollicular epidermis filaggrin labelling was demonstrated on keratohyalin granules and in the lowermost cornified cells, whereas in ADI patients crumbly keratohyalin granules were present that did not show specific labelling for filaggrin. In normal ridged skin only the major (more electron-dense) component reacted with anti-filaggrin, whereas the attached (less electron-dense) component did not react. Ridged skin of ADI patients contained globular keratohyalin that did not react with anti-filaggrin, thus corresponding to the attached keratohyalin component in normal ridged skin. Our results provide a visible counterpart to the recent biochemical investigations of keratohyalin protein heterogeneity and contribute to the understanding of terminal differentiation in human skin and of the defective keratohyalin synthesis in ADI.

Adult↗
PubMed1994

Euro Skin Bank: large scale skin-banking in Europe based on glycerol-preservation of donor skin.

Although skin banking has been well developed through the years as a means of providing sufficient skin which is instantly accessible to the burn patient, the methods of preservation and the scale on which various institutions bank skin vary considerably. In 1984, the Dutch National Skin Bank started using glycerol as a preservant for skin allografts. Since then there has been a marked increase in both the volume of glycerol skin grafts applied and the area over which these have been distributed. The procedure and organizational aspects of the Euro Skin Bank, as our own institution is now called, and its current method of skin preservation are described.

Adolescent↗