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At least 793 records · Page 44Linked to original sources
PubMed1991

Skin banking: a simple method for cryopreservation of split-thickness skin and cultured human epidermal keratinocytes.

A simple unit has been developed for the simultaneous passive cooling of small and large amounts of allograft or autograft split-thickness skin, as well as cultured human epidermis. An expanded polystyrene box of variable size, aluminum plates, and cellulose tissue are fused. This unit is cooled in a -70 degrees C constant-temperature mechanical refrigerator. Maximal cooling rates of -1.3 degrees C min-1 are obtained in a box with a constant wall thickness of cellulose tissue. The cooling rate can be varied by altering the number of cellulose layers. Exothermic temperature plateaus associated with skin cooled in this unit last for less than 0.3 minutes. The viability of the cryopreserved skin was determined by using up to four methods simultaneously: a dye-exclusion test with trypan blue; glucose consumption; production of lactate; and carbon-13 nuclear magnetic resonance spectroscopy. Using a cryoprotectant medium with 15% (vol/vol) glycerol for split-thickness skin 0.25 mm thick, a storage time of up to 509 days at -70 degrees C was observed, with only a small decrease in viability (trypan blue, 62.5%; glucose consumption, 71 to 90% compared with freshly harvested skin). Storage in liquid nitrogen did not significantly improve results (p greater than 0.05).

Adult↗
PubMed1998

Multiple lentigines syndrome: a comparison of normal skin and lentiginous skin by electron microscopy and immunohistochemical staining.

A 26-year-old Korean man exhibited generalized lentigines, a slight prominence of the chin, short stature, and a familial history consistent with the autosomal dominant mode of inheritance. The multiple lentigines appeared at the age of 1 and spread over his entire body including the scalp, palms, and soles by the age of 4. There were several large dark pigmented spots on the trunk, but no other skin abnormalities were found. We performed histologic studies of the normal skin and the lentigo by both electron and light microscopy with immunohistochemical stains. Routine hematoxylin-eosin staining of the pigmented skin revealed heavily pigmented basal and spinous layers and prominent rete ridges. Fontana-Masson stain showed enormous black pigmentations on the basal and spinous layers of the pigmented macule. S-100 protein stain of the pigmented lesion demonstrated an increased number of melanocytes per unit skin area. Ultrastructural studies showed the presence of extensive aggregated melanosomes within the keratinocytes in the epidermis of lentigo, but not the presence of giant melanosomes in either normal skin or lentigines.

Adult↗
PubMed1989

Comparison of disposable diapers with fluff absorbent and fluff plus absorbent polymers: effects on skin hydration, skin pH, and diaper dermatitis.

Diaper dermatitis results from the action of a number of physical and chemical factors on the skin. While its etiology is complex, there is agreement that prolonged contact between wet diapers and the skin leading to excessive hydration of the stratum corneum and reduced barrier function is a primary factor. Recent research also indicates that pH elevation resulting from ammonia production increases the probability of skin damage due to fecal enzyme activity. New diapers containing absorbent polymers blended with cellulose fluff in the absorbent core have been developed. The absorbent polymer binds fluids and controls pH in the diaper environment. To assess the effectiveness of these diapers, a clinical study was conducted with approximately 150 infants over 15 weeks, using fluff diapers and absorbent polymer diapers. The results clearly showed that the diapers with absorbent polymer provide a better skin environment than those with fluff only with respect to lower skin wetness and pH control (instrumental measurements). In addition, the clinicians' grades indicated a directional reduction in diaper rash severity.

Body Water↗
PubMed1994

Retinoic acid induces expression of PA-FABP (psoriasis-associated fatty acid-binding protein) gene in human skin in vivo but not in cultured skin cells.

PA-FABP (psoriasis-associated fatty acid-binding protein) is a new member of a group of low-molecular-weight proteins that are highly up-regulated in psoriatic skin and that share similarity to fatty acid-binding proteins. In this study we demonstrate that PA-FABP transcripts are expressed in human skin in vivo and that topical application of 0.05% retinoic acid (RA) cream results in a rapid induction of PA-FABP transcripts following treatment for 16 hours and persists at increasing levels after 48 and 96 h of RA treatment. The PA-FABP mRNA response to RA was reduced by approximately 50% when patients concurrently were treated with RA and 0.025% clobetasol propionate (CLO) for 48 and 96 h, whereas treatment with CLO alone resulted in PA-FABP transcript levels not significantly different from vehicle-treated skin. When comparing the effects of a well-known irritant, sodium lauryl sulfate (SLS), to those of RA and its vehicle, 0.05% RA cream but not 2% SLS in RA vehicle caused PA-FABP mRNA induction after 16 h. SLS treatment of human skin for 96 h caused a slight increase in PA-FABP transcripts, but markedly less than that observed in response to RA treatment. Incubation of cultured human keratinocytes or skin fibroblasts with RA for up to 48 h did not significantly induce PA-FABP transcripts. Expression of PA-FABP message in keratinocytes was observed to be induced by calcium and fetal calf serum (FCS), while tetra-decanoyl phorbol acetate (TPA) caused little or no induction.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMedDate not supplied

EEMCO guidance to the in vivo assessment of tensile functional properties of the skin. Part 1: relevance to the structures and ageing of the skin and subcutaneous tissues.

From an engineering point of view, the skin and subcutaneous tissue represent an integrated load-transmitting structure. It is subjected to intrinsic and environmental influences. An attempt to use a four-layered model is offered to explain how the integument withstands and transmits loads through deforming appropriately. The stratum corneum, the association between the living epidermis and papillary dermis, the reticular dermis and the hypodermis have each their own intimate structures whose tensile functions are ideally balanced to respond adequately to the casual mechanical demands. A series of physiological variables, ageing and skin diseases alter the tensile functions of the organ. In the overall analysis, truly comprehensive multidisciplinary approaches in this field have brought advances in the understanding of functional skin biology. The assessment of tensile functions of skin also provides incentives for progress in skin care.

Aging↗
PubMed1996

Transplantation of systemic sclerosis (SSc) skin grafts into severe combined immunodeficient mice: increased presence of SSc leukocytes in SSc skin grafts and autoantibody production following autologous leukocyte transfer.

This study was performed to evaluate the potential of the severe combined immunodeficient (Scid) mouse as a model to study the pathogenesis of systemic sclerosis (SSc). Scid mice were divided into three treatment groups: group 1 received skin grafts and autologous peripheral blood mononuclear cells (PBMC) from either SSc patients or normal individuals, group 2 received only SSc or normal skin grafts, and group 3 received only SSc or normal PBMC transfer. Antinuclear antibodies with a similar expression pattern as in the donor patients were detected in SSc-Scid group 1. Increased numbers of human PBMC were detected after autologous PBMC transfer in normal or SSc skin grafts without crossover into the adjacent mouse tissue. The CD4/CD8 ratio in these infiltrates was approximately 1.0. Although SSc skin transplantations and autologous PBMC transfer into Scid mice did not reproduce the inflammatory events found in the original SSc skin biopsies, these mice could be useful to study the expression of SSc-specific autoantibodies.

Adoptive Transfer↗
PubMed1987

Histologic changes in nude mouse skin and human skin xenografts following exposure to sulfhydryl reagents: arsenicals.

This report documents the histological changes in nude mouse skin and in human skin xenografts on nude mice following exposure to phenyldichloroarsine (PDA), a vesicant arsenical. Under light microscopy, we observed in PDA-treated human skin grafts: 1) degeneration of epidermal cell nuclei (apparent by 2 hr after exposure with increasing severity through 48 hr); 2) loss of epidermal cytoplasmic basophilia (apparent by 4 hr, maximal within 12 hr); 3) epidermal cytoplasmic vacuolization (vacuoles appeared within 4 hr and increased in size through 24 hr); 4) cleft formation within the basement membrane zone (apparent by 12 hr, increasing in severity through 24 hr); 5) inflammation evidenced by polymorphonuclear leukocyte (PMN) infiltration (apparent by 4 hr and increasing through 48 hr). The PMNs frequently formed a wall around the lesion, but did not infiltrate the treated area. Nude mouse skin reacted faster to PDA than did the grafts, but the histological changes were similar. Nude mouse hair follicles and sebaceous glands showed similar cellular changes at approximately the same time as did epidermal cells. Transmission electron microscopy of mouse skin exposed to PDA revealed a widening of intercellular spaces with attenuation of desmosomes. The subepidermal clefts resulted from separation within the lamina lucida with the lamina densa forming the base of the cleft. Diphenylchloroarsine caused lesions histologically indistinguishable from those of PDA. Lesions resulting from exposure to other sulfhydryl-binding compounds were very different from arsenical lesions. The arsenical-sensitive cellular constituents were not identified.

Animals↗
PubMed1987

Relationship between maturation of the skin and electrical skin resistance.

In 16 newborn infants (24 6-39 wk 6 days 830-3390 g) at ages between 0-70 days, the skin's electrical resistance was measured. Over 30 min we sequentially measured direct current resistance between two skin electrodes placed on the abdomen. The resistance was found to be low in very premature infants with gestation ages of 30 wk or less. It increased with both gestational age and postnatal age. In these infants, the resistance measured at 30 min during the first 4 days of life (3.4 +/- 0.3 K omega; mean +/- SD) was significantly less than that found at 20-70 days (8.8 +/- 1.2 k omega; p less than 0.001). The relationship between the infant's electrical skin resistance (y) and the gestational age (x) best fit the exponential formula: y = 7.42 X e0.24x X 10(-4) + 2.74. This formula shows that the electrical skin resistance increases exponentially during the last trimester. The measurement of electrical skin resistance is a quantitative method that can be utilized to evaluate the gestational age of infants.

Galvanic Skin Response↗
PubMed1993

Evaluation of skin damage of cyclic monoterpenes, percutaneous absorption enhancers, by using culture human skin cells.

The cytotoxicity of monoterpenes, percutaneous absorption enhancers, to cultured human skin cells was investigated in order to quantitatively estimate their skin damage. A neutral red bioassay with epidermal keratinocytes and a contraction test of collagen gel in which dermal fibroblasts were cultured were employed for evaluating the cytotoxicity of terpenes. In the neutral red bioassay, keratinocyte proliferation was inhibited on the addition of terpenes, and cell survival remarkably decreased with an increase in the concentration of terpenes fed into the culture well. When the fibroblasts were cultured in a collagen gel matrix, the lattice of collagen contracted as the cells grew. Therefore, the application of cytotoxic agents brings about an inhibition of collagen gel contraction induced by the fibroblasts. Strong inhibition was observed in the cases of hydrocarbons in terpenes, and the inhibition was dependent on the concentration of these compounds added in the culture medium. The cytotoxicity of terpenes was compared with the skin damage evoked by the application of terpenes in rats in vivo. As a result, it was considered that the skin irritation caused by terpenes was predictable to a certain extent by means of the cytotoxic study of cultured human skin cells.

Animals↗
PubMed1997

Relationship between amount of beta-blockers permeating through the stratum corneum and skin irritation after application of beta-blocker adhesive patches to guinea pig skin.

We evaluated the relationship between the cumulative amounts of 5 kinds of beta-blockers (alprenolol, oxprenolol, timolol, acebutolol and atenolol) permeating through the stratum corneum and a* values obtained by measuring the formation of erythema, a skin irritation reaction, with a chromameter after transdermal application of adhesive patches containing 2 beta-blocker to the skin of guinea pigs. The cumulative amount of beta-blocker released from each adhesive patch to the skin increased with the increase in application time. The contents of alprenolol, oxprenolol and timolol in the stratum corneum and in the stripped skin increased markedly up to 4 h after application and thereafter were maintained at high levels up to 24 h. The contents of acebutolol and atenolol, on the other hand, increased up to 24 h, but these values were low. a* values of all adhesive patches 24 h after application were higher than those before application. The correlation coefficients between the cumulative amounts of alprenolol, oxprenolol, timolol, acebutolol or atenolol permeating through the stratum corneum and (delta a* -delta a*Placebo) values were 0.739, 0.717, 0.722, 0.551 and 0.633, respectively. The correlation coefficient calculated by averaging the cumulative amounts of 6 kinds of beta-blockers permeating through the stratum corneum [including propranolol which was reported previously (Kobayashi I., et al., Biol. Pharm. Bull., 19, 839-844 (1996))] was 0.731, higher than the correlation coefficient between contents of these beta-blockers in the stripped skin and (delta a* -delta a*Placebo) values (r = 0.552). This suggests that there was a high correlation between the cumulative amounts of beta-blockers permeating through the stratum corneum and (delta a* -delta a*Placebo) values.

Acebutolol↗
PubMed2000

Sunscreens, skin photobiology, and skin cancer: the need for UVA protection and evaluation of efficacy.

Sunscreens are ultraviolet radiation (UVR)-absorbing chemicals that attenuate the amount and nature of UVR reaching viable cells in the skin. They are selected and tested for their ability to prevent erythema. No sunscreen prevents photodamage, as it has been demonstrated that suberythemal doses of UVR cause a variety of molecular changes (including DNA damage) in these cells. Furthermore, the spectrum of UVR reaching viable cells is altered by topically applied sunscreen. In this review, the basic aspects of sunscreens and skin photobiology are reviewed briefly. Although there can be no question concerning the efficacy of sunscreens for the prevention of erythema, questions remain because of the possible cumulative effects of chronic suberythemal doses and the increased exposure of skin cells to longer UVR wavelengths. The current major issue surrounding sunscreens involves their ability to protect skin cells against the effects of UVA radiation. These UVA effects may be direct damage (base oxidations) or effects on the skin immune system, yet there is no uniformly accepted method for the evaluation of UVA protection. This review is focused primarily on the latter topic covering action spectra that implicate the need for UVA protection. In addition, in vivo and in vitro methods proposed for the evaluation of candidate sunscreen formulations of UVA protective ability are reviewed. Finally, revisions in the terminology used to describe the protection afforded by sunscreens are suggested. It is proposed that SPF ("sun" protection factor) be renamed "sunburn" protection factor and that "critical wavelength" be designated "long wave index."

Animals↗
PubMed2005

Oestrogen functions in skin and skin appendages.

Oestrogens have significant effects on different cell types important in skin physiology, including the epidermal keratinocytes, dermal fibroblasts and melanocytes. In addition, they can also modulate skin appendages such as the hair follicle, the sebaceous gland and the apocrine glands. Oestrogens may also have important modulatory roles in events such as skin ageing, pigmentation, hair growth, sebum production and skin cancer. It is now recognised that oestrogens can modulate their actions via two distinct intracellular receptors (ERalpha and ERbeta) or via cell surface receptors, which activate specific second messenger signalling pathways. This paper highlights the effects of oestrogens on different components of the skin and reviews some of the more recent developments in terms of receptor expression and cell signalling pathways.

Estrogens↗
PubMed1982

[Irritation test of dexamethasone valerate (DV-17) and other steroid ointments in rabbits. Skin and eye primary irritation tests, and skin cumulative irritation test].

The skin and eye primary irritation tests, and skin cumulative irritation test were performed on male rabbits, which were topically treated with a volume of 1 g/body of 0.06% and 0.12% dexamethasone valerate (DV-17) ointments as a test drug, and 0.1% hydrocortisone butyrate (HB) and 0.12% betamethasone valerate (BMV) ointments as an active control drug in order to evaluate the topical and systemic effects. No skin and eye primary irritations except minimal skin erythema and slight conjunctival redness were seen in above four corticosteroids. Judging from the results such as skin atrophy, inhibition of body weight gains, and decreases of thymus, spleen and adrenal weights, the potency of toxicities among the four corticosteroid ointments appeared to be as follows: 0.12% DV-17, 0.12% BMV greater than 0.1% HB greater than 0.06% DV-17.

Adrenal Cortex Hormones↗
PubMed1989

Evaluation of the hydration and the water-holding capacity in atopic skin and so-called dry skin.

The hydration, the hygroscopicity and the water-holding capacity as well as the rate of water loss were measured in 1) dry non-eczematous skin in 13 patients (mean age 32 years) with atophic dermatitis (AD), 2) dry, xerotic skin of old patients (mean age 75 years) and 3) 17 controls (mean age 36 years) with normal skin and no history of AD. Significantly higher water flux was found in patients with AD compared to the other groups while all the other functional parameters were much lower. The obtained data suggest different functional disturbances in dry skin of patients with AD compared to old, dry (xerotic) skin.

Adult↗
PubMed1985

Exposure to cutting oils and its relation to skin tumors and premalignant skin lesions on the hands and forearms.

In a cohort study the incidence of skin tumors on the hands and forearms of 682 turners exposed to cutting oils was compared to the incidence of the general male population and of office workers. Among the 682 turners, five premalignant squamous cell tumors and eight keratoacanthomas were found between 1960 and 1980. Five of this total of 13 turners with primary skin tumors had another skin tumor as well. Among the 682 men there were four cases of scrotal cancer. Among the 375 office workers examined, no malignant or premalignant tumors or keratoacanthomas were found on the hands or forearms. No primary skin tumors were found among the turners after 1975, when the acid-refined mineral oils were replaced by solvent-refined oils containing a far lower concentration of polyaromatic hydrocarbons, which are probably the cancerogenic agent in the oils. The study shows a greatly increased risk of skin tumors on the hands and forearms of workers exposed to acid-refined mineral oils. Individual susceptibility also seems to be indicated.

Adult↗
PubMed2002

[Skin substitutes and skin culture].

Ideal skin substitutes would reproduce normal skin in its various functions. Even in the absence of such ultimate products, the ones in use today represent a major part in local burn care as agents promoting wound healing and minimising the long-term consequences after burn injuries. They originate from natural structures as well as (bio)engineering concepts. The application fields cover all depth of burns as well as skin donors' areas and even secondary surgery. Among other techniques, skin allografts followed by autografts or autologous keratinocytes cultures especially over the integrated dermis and artificial skin Integra then subsequently grafted with very thin autografts are significant methods in treating extensive injuries when utilised according to clinical status accurately defined. However further advances are essential for improving the life of burn survivors.

Burns↗
PubMed1992

Skin graft and skin equivalent in burns.

The problem in extensive burns is the relative lack of available donor sites for skin grafting. Before the burnt areas can be covered, infection often sets in and the patients may then succumb. Skin grafts can be expanded in a limited way. Biological dressings or synthetic dressings can be used to buy time till donor sites become available. Cultured epithelium grown in the tissue culture laboratory permits massive expansion of skin and has been used with success as epithelial autografts in patients. Composite skin equivalents or skin substitutes have been developed and show promise.

Biological Dressings↗
PubMed2006

A review of skin and the effects of aging on skin structure and function.

As the most visible and vulnerable organ of the human body, the skin is anatomically and functionally affected by aging. Maintaining skin integrity starts with understanding skin anatomy, physiology, and function and recognizing conditions as well as aspects of care that may affect structure and function. Research suggests that appropriate skin cleansing procedures and protection, as well as nutritional and environmental interventions, may help reduce some of the effects of aging and have positive psychological and health outcomes. Optimizing skin health in the elderly will help maintain its integrity and, as such, should be the first step in any wound prevention program.

Aging↗