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Query: UMLS:C0849640 (skin damage)
 1,516 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was conducted to determine whether oral and/or topical selenium (Se) supplementation can reduce the incidence of acute and/or chronic damage to the skin (i.e., sunburn and pigmentation and/or skin cancer, respectively) induced by ultraviolet (UV) irradiation in mice. Groups of 38 BALB:c female mice or 16 Skh:2 hairless pigmented mice were treated with 1) lotion vehicle, 2) 0.02% L-selenomethionine (SeMet) lotion, or 3) vehicle and 1.5 ppm SeMet in the drinking water. Within each group, 30 BALB:c mice or 12 Skh:2 mice were given UV irradiation (Westinghouse FS 40 bulbs) three times per week in doses of 0.575 and 0.24 J/cm2, respectively. The animals' weights and food intakes and the Se concentrations of skin and liver were measured. Skin biopsies were taken from the backs and abdomens of all animals to evaluate the relative amounts of Se and the damage by UV irradiation. Skin pigmentation was scored, and the total number of clinically detectable skin tumors per animal was counted weekly. Results showed that the skin Se concentrations in areas of application of the lotion containing SeMet were greater than those of animals given comparable oral doses, while the Se concentrations of untreated skin and liver were similar to those of animals receiving oral Se. Mice treated with Se showed no signs of toxicity and had significantly less skin damage by UV irradiation, as indicated by reduced inflammation and pigmentation and by later onset and lesser incidence of skin cancer.
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PMID:The effects of topical and oral L-selenomethionine on pigmentation and skin cancer induced by ultraviolet irradiation. 158 7

A 2% commercial solution formulation of 5-fluorouracil (5-FU) was significantly better at delivering 5-FU than either a 1% or 5% solution. Among single component suspension formulations the highest transdermal delivery was obtained from the vehicle in which 5-FU was least soluble, isopropyl myristate (IPM), while changes in the total suspended concentration of 5-FU in propyleneglycol (PG) had no significant effect on transdermal delivery by those suspensions. A prodrug of 5-FU/IPM was significantly better at delivering 5-FU than any of the formulations. The trends in relative rates of delivery of 5-FU by the formulations and the prodrug were the same in skin of hairless mice and humans. The mouse skin was about ten times more permeable than the human skin. Second application studies to assess skin damage caused by the formulations also showed the same trend in skin of hairless mice and humans: all of the formulations caused some damage.
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PMID:Transdermal delivery of 5-fluorouracil through skin of hairless mice and humans in vitro: a comparison of the effect of formulations and a prodrug. 207 50

Albino hairless mice (Skh:HR-1) exposed chronically to suberythemal doses of ultraviolet radiation develop visible skin changes, histological alterations, and tumors. Topical treatment of mice with solutions of superoxide-scavenging antioxidants (such as alpha-tocopherol, ascorbic acid, propyl gallate and Trolox) prior to each UVB radiation exposure reduced significantly the severity of these events. Tocopherol esters and ascorbyl palmitate were not as effective as the parent compounds in providing protection. The data suggest a role for superoxide in UVB radiation-induced skin photoaging and the protective potential of superoxide scavengers. In contrast, the severity of UVA radiation-induced mouse skin damage was not reduced by topical application of the antioxidants tested here.
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PMID:Photoprotective effect of superoxide-scavenging antioxidants against ultraviolet radiation-induced chronic skin damage in the hairless mouse. 216 96

Albino hairless mice (Skh: HR-1) exposed chronically to sub-erythemal doses of UV radiation display physical, visible and histological alterations. Using narrow bandwidth radiation covering the UV radiation spectrum from 280-380 nm, the wavelength dependence of these alterations was determined. The wavelength dependence spectra indicate that for all but one parameter measured (skin sagging), UV-B radiation is considerably more efficient than UV-A radiation in producing changes in the skin. However, in natural sunlight there is considerably more UV-A than UV-B radiation, providing the potential for UV-A to have a larger contribution to skin damage than UV-B. This argues in favor of using broad spectrum photoprotective agents to shield the skin adequately from UV-induced aging. The spectra were also used to develop potential associations among events by determining which events occur at similar wavelengths. There seems to be a correspondence between mouse visible skin wrinking (UV-B event) and two histological events: increase in glycosaminoglycans and alteration in collagen. There was no obvious correspondence among UV-A-induced events.
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PMID:Wavelength dependence of histological, physical, and visible changes in chronically UV-irradiated hairless mouse skin. 262 90

Sunscreens containing 5-methoxypsoralen (5-MOP) are currently being marketed to promote tanning by inducing psoralen-mediated ultraviolet (UV) A (320-400 nm) melanogenesis. The rationale is that this may prevent UVB (290-320 nm) radiation-induced skin damage. However, mouse studies have shown that 5-MOP has the same cutaneous photocarcinogenic potential as 8-methoxypsoralen. In addition, the 5-MOP--containing sunscreen Sun System III (SS III), when combined with UVA, induces epidermal ornithine decarboxylase activity, an enzyme associated with tumor promotion. Therefore, we investigated whether SS III had sufficient psoralen concentration to be tumorigenic in hairless mice exposed to chronic, intermittent UVA radiation. SS III was applied to hairless mice 5 days per week for 20 weeks. After each application the mice were exposed to 2.5 to 10 joules/cm2 UVA radiation. All test groups developed atypical squamous papillomas in direct proportion to the dosage of UVA radiation received. A shorter latency period for tumor development was seen with larger UVA doses. Test animals followed up to 1 year developed invasive squamous cell tumors. Control groups (SS III without UVA and UVA without SS III) remained free of tumors. Animals receiving SS III plus UVA developed persistent skin thickening and increased dermal cyst formation similar to that reported with chronic exposure to UVB, a known carcinogenic wavelength. Over-the-counter sunscreens containing 5-MOP do contain sufficient psoralen concentrations to cause cutaneous phototoxicity and photocarcinogenicity in mice, and their use in humans should be discouraged in the interest of preventing further UV-induced skin damage and skin cancer.
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PMID:Psoralen-containing sunscreen is tumorigenic in hairless mice. 686 46

The barrier properties of hairless mouse skin were examined by separating the skin into its component epidermal and dermal strata, using both mechanical and thermal techniques, and then assessing the permeability of each stratum to the homologous alkanols. The permeability data, when compared to those obtained previously for full-thickness hairless mouse skin and to new data for the permeability of the alcohols through a perfect lipid membrane, allow assignment of diffusional resistances to the respective, anatomically distinguishable membrane strata. It was found that the principal barrier for the lower alkanols is the epidermis, which contains the stratum corneum. The effective aqueous tissue resistances of the cellular and aqueous strata of full skin, the epidermis, and the dermis were estimated using sectioned skins. This resistance was much greater than that of an equivalent thickness of water. These data and methods represent a novel approach in the permeation analysis of a biological tissue and offer a means of estimating the effects of skin damage on percutaneous absorption.
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PMID:Permeation of hairless mouse skin II: membrane sectioning techniques and influence on alkanol permeabilities. 701 28

The acute skin phototoxicity in hairless mice resulting from applications of crude shale oil or natural petroleum oil and exposure to near ultraviolet light has been investigated. In addition, the absorption and excitation-emission spectra of these oils have been described. While the application of crude shale oil alone was shown to elicit acute skin damage, the combination of the crude shale oil and near ultraviolet light induced skin damage much more severe than that produced by either agent alone. In contrast, the application of the natural petroleum oil and near ultraviolet light was less toxic than that of the crude shale oil in the absence of light. These results suggest that a potential health hazard exists from contact with shale oil compounds and exposure to near ultraviolet light from either the sun or artificial sources.
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PMID:Acute skin phototoxicity in hairless mice following exposure to crude shale oil or natural petroleum oil. 721 25

While assessing the protective effect of broad-spectrum sunscreens against chronic UVA radiation, we observed a paradoxical worsening of skin damage with one product. To further examine this finding, five proprietory broad-spectrum sunscreens were applied to albino hairless mice irradiated thrice weekly for 32 weeks with a UVASUN lamp (> 340 nm). Appropriate age-matched controls were included. After approximately 12 weeks, two sunscreens induced a marked dermatitis. Biopsies showed damage greatly exceeding that found in UVA-irradiated, unprotected controls. Histologically, elastic fibers were hyperplastic, coalescing into elastotic clumps. Glycosaminoglycans also increased. Collagen damage was notable since UVA alone does not induce a histologic change. Electron microscopy confirmed these findings. Two other sunscreens provided nearly complete protection. Against chronic UVB radiation, the two UVA photoirritating sunscreens provided substantial protection. Since the UVA sunfilter, oxybenzone, was the same in all sunscreens, we postulate that an irritating component of the vehicle was responsible for the UVA-induced photoirritation. The fifth sunscreen produced severe damage with UVB and UVA.
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PMID:Photoirritation: a new photobiologic phenomenon induced by long wavelength UVA radiation in hairless mice treated with broad-spectrum sunscreens. 765 81

Erythema is the initial symptom that occurs after sulfur mustard (HD) cutaneous exposure. The time course of HD-induced erythema is similar to that observed after UV irradiation, which can be reduced by indomethacin. Sulfur mustard lethality is decreased by using promethazine, which is an antihistamine. Niacinamide can reduce microvesication after HD vapor exposure in hairless guinea pig (HGP) skin. The present study examines the effect of the combined administration of niacinamide, indomethacin and promethazine used alone or in all possible combinations on the degree of erythema and histopathologic skin damage after HD exposure in HGP. Niacinamide (750 mg kg-1, i.p.), promethazine (12.5 mg kg-1, i.m.) or indomethacin (4 mg kg-1, p.o.) used singly or in combination was given as a 30-min pretreatment before an 8-min HD vapor cup skin exposure. Using a combination pretreatment of niacinamide, promethazine and indomethacin, erythema was reduced at 4 (91%) and 6 (55%) h, but not 24 h after HD. The incidence of histopathological skin changes (microvesicles, follicular involvement, epidermal necrosis, intracellular edema and pustular epidermatitis) 24 h after HD was not reduced. This study indicates that HD-induced erythema may result from several different mechanisms, including inflammation, histamine release and DNA damage. It is suggested that two phases of inflammation may occur: an early phase sensitive to antihistamines and non-steroidal antiinflammatory drugs and a late phase of extensive cell damage that was not sensitive to these drug pretreatments.
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PMID:Reduction of erythema in hairless guinea pigs after cutaneous sulfur mustard vapor exposure by pretreatment with niacinamide, promethazine and indomethacin. 778 59

In this ultrastructural study, albino hairless mice were irradiated with long-wavelength ultraviolet (UVA) (340-400 nm) thrice weekly for 32 weeks for a cumulative dose of 8000 J/cm2. Biopsies were taken from these mice, from age-matched unirradiated controls, and from mice irradiated with UVB for 20-30 weeks with a cumulative dose of approximately 6-9 J/cm2. The most striking UVA-induced changes were 1) elastic fiber hyperplasia without evidence of fiber disintegration, 2) a large increase in randomly deposited microfibrils; 3) massive duplication of vascular basement membrane; 4) extensive endothelial cell damage; and 5) collagen fibers with smaller diameters but without apparent damage. By contrast, after UVB, the hyperplastic elastic fibers frequently appeared to be degraded. Microfibrils were only moderately increased and remained in an organized array. Also, unlike with UVA, the epidermal basement membrane was duplicated whereas that of the vessels was mainly spared. Collagen fibers showed evidence of dissolution. Thus, ultrastructural features provide further evidence that skin damage induced by UVA can be dissimilar to that induced by UVB.
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PMID:UVA-induced ultrastructural changes in hairless mouse skin: a comparison to UVB-induced damage. 842 42


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