Prevalence of whole-body skin self-examination in a population at high risk for skin cancer (Australia)

Objective: Whole-body skin self-examination (SSE) with presentation of suspicious lesions to a physician may improve early detection of melanoma. The aim of this study was to establish the prevalence and determinants of SSE in a high-risk population in preparation for a community-based randomised controlled trial of screening for melanoma. Methods: A telephone survey reached 3110 residents older than 30 years (overall response rate of 66.9%) randomly selected from 18 regional communities in Queensland, Australia. Results: Overall, 804 (25.9%) participants reported whole-body SSE within the past 12 months and 1055 (33.9%) within the past three years. Whole-body SSE was associated in multivariate logistic regression analysis with younger age (< 50 years); higher education; having received either a whole-body skin examination, recommendation or instruction on SSE by a primary care physician; giving skin checks a high priority; concern about skin cancer and a personal history of skin cancer. Conclusion: Overall, the prevalence of SSE in the present study is among the highest yet observed in Australia, with about one-third of the adult population reporting whole-body SSE in the past three years. People over 50 years, who are at relatively higher risk for skin cancer, currently perform SSE less frequently than younger people.

Sunscreen penetration of human skin and related keratinocyte toxicity after topical application

Sunscreen skin penetration and safety assessment should be considered together in order to ensure that in vitro cytotoxicity studies examine relevant doses of these organic chemical UV filters to which viable epidermal cells are realistically exposed. In this study, we sought to determine whether sufficient topically applied sunscreens penetrated into human viable epidermis to put the local keratinocyte cell populations at risk of toxicity. The penetration and retention of five commonly used sunscreen agents ( avobenzone, octinoxate, octocrylene, oxybenzone and padimate O) in human skin was evaluated after application in mineral oil to isolated human epidermal membranes. Sunscreen concentration - human keratinocyte culture response curves were then defined using changes in cell morphology and proliferation ( DNA synthesis using radiolabelled thymidine uptake studies) as evidence of sunscreens causing toxicity. Following 24 h of human epidermal exposure to sunscreens, detectable amounts of all sunscreens were present in the stratum corneum and viable epidermis, with epidermal penetration most evident with oxybenzone. The concentrations of each sunscreen found in human viable epidermis after topical application, adjusting for skin partitioning and binding effects, were at least 5-fold lower, based on levels detected in viable epidermal cells, than those appearing to cause toxicity in cultured human keratinocytes. It is concluded that the human viable epidermal levels of sunscreens are too low to cause any significant toxicity to the underlying human keratinocytes. Copyright (C) 2005 S. Karger AG, Basel.

Collagen in the scarless fetal skin wound: Detection with Picrosirius-polarization

Our group has developed an ovine model of deep dermal, partial-thickness burn where the fetus heals scarlessly and the lamb heals with scar. The comparison of collagen structure between these two different mechanisms of healing may elucidate the process of scarless wound healing. Picrosirius staining followed by polarized light microscopy was used to visualize collagen fibers, with digital capture and analysis. Collagen deposition increased with fetal age and the fibers became thicker, changing from green (type III collagen) to yellow/red (type I collagen). The ratio of type III collagen to type I was high in the fetus (166), whereas the lamb had a much lower ratio (0.2). After burn, the ratios of type III to type I collagen did not differ from those in control skin for either fetus or lamb. The fetal tissue maintained normal tissue architecture after burn while the lamb tissue showed irregular collagen organization. In conclusion, the type or amount of collagen does not alter significantly after injury. Tissue architecture differed between fetal and lamb tissue, suggesting that scar development is related to collagen cross-linking or arrangement. This study indicates that healing in the scarless fetal wound is representative of the normal fetal growth pattern, rather than a response to burn injury.

Altered cell surface expression of human MC1R variant receptor alleles associated with red hair and skin cancer risk

The human melanocortin-1 receptor gene (MC1R) encodes a G-protein coupled receptor that is primarily expressed on melanocytes, where it plays a key role in pigmentation regulation. Variant alleles are associated with red hair colour and fair skin, known as the RHC phenotype, as well as skin cancer risk. The R151C, R160W and D294H alleles, designated 'R', are strongly associated with the RHC phenotype and have been proposed to result in loss of function receptors due to impaired G-protein coupling. We recently provided evidence that the R151C and R160W variants can efficiently couple to G-proteins in response to alpha-melanocyte stimulating hormone. The possibility that altered cellular localization of the R151C and R160W variant receptors could underlie their association with RHC was therefore considered. Using immunofluorescence and ligand binding studies, we found that melanocytic cells exogenously or endogenously expressing MC1R show strong surface localization of the wild-type and D294H alleles but markedly reduced cell surface expression of the R151C and R160W receptors. In additional exogenous expression studies, the R variant D84E and the rare I155T variant, also demonstrated a significant reduction in plasma membrane receptor numbers. The V60L, V92M and R163Q weakly associated RHC alleles, designated 'r', were expressed with normal or intermediate cell surface receptor levels. These results indicate that reduced receptor coupling activity may not be the only contributing factor to the genetic association between the MC1R variants and the RHC phenotype, with MC1R polymorphisms now linked to a change in receptor localization.

Community perceptions of suspicious pigmented skin lesions: are they accurate when compared to general practitioners?

Community responses (n = 925, response rate = 71%) of a series of eight photographs of pigmented skin lesions were compared against those of general practitioners (n = 114, response rate = 77%), considered to be the most relevant gold standard. The eight photographs included three melanomas, two potentially malignant lesions and three benign pigmented lesions. Over the pool of lesions examined, the average probability that community members thought a lesion was likely to be skin cancer (0.68 [99% CI = 0.66-0.69]) was higher (p < 0.0001) than that of the comparison general practitioners 0.58 [99% CI = 0.55-0.62]. This reflects a general (but not consistent) inflated propensity to over-diagnose among community members. The average probability that respondents indicated they would seek medical advice for a lesion was 0.71 [99% CI = 0.70-0.73]. As expected, this was strongly associated with their perceptions of the skin lesion. These results suggest that the community can play a valuable role in assessing the need for medical evaluation of pigmented skin lesions. (c) 2004 International Society for Preventive Oncology. Published by Elsevier Ltd. All rights reserved.

Effects of vehicle and region of application on absorption of hydrocortisone through canine skin

Objective-To determine the effects of various vehicles on the penetration and retention of hydrocortisone applied to canine skin. Sample Population-20 canine skin samples obtained from the thorax, neck, and groin regions of 5 Greyhounds. Procedure-Skin was harvested from dogs after euthanasia and stored at -20 degrees C until required. The skin was then defrosted and placed into diffusion cells, which were maintained at approximately 32 degrees C by a water bath. Saturated solutions of hydrocortisone that contained trace amounts of radiolabelled [C-14]-hydrocortisone in each vehicle (ie, PBS solution [PBSS] alone, 50% ethanol [EtOH] in PBSS [wt/wt], and 50% propylene glycol in PBSS [wt/wt]) were applied to the outer (stratum corneum) surface of each skin sample, and aliquots of receptor fluid were collected for 24 hours and analyzed for hydrocortisone. Results-The maximum flux of hydrocortisone was significantly higher for all sites when dissolved in a vehicle containing 50% EtOH, compared with PBSS alone or 50% propylene glycol, with differences more prominent in skin from the neck region. In contrast, higher residues of hydrocortisone were found remaining within the skin when PBSS alone was used as a vehicle, particularly in skin from the thorax and neck. Conclusions and Clinical Relevance-Penetration of topically applied hydrocortisone is enhanced when EtOH is used in vehicle formulation. Significant regional differences (ie, among the thorax, neck, and groin areas) are also found in the transdermal penetration and skin retention of hydrocortisone. Variability in clinical response to hydrocortisone can be expected in relation to formulation design and site of application.

Multiphoton high-resolution 3D imaging of Langerhans cells and keratinocytes in the mouse skin model adopted for epidermal powdered immunization

Langerhans cells (LCs) can be targeted with DNA-coated gold micro-projectiles ("Gene Gun") to induce potent cellular and humoral immune responses. It is likely that the relative volumetric distribution of LCs and keratinocytes within the epidermis impacts on the efficacy of Gene Gun immunization protocols. This study quantified the three-dimensional (3D) distribution of LCs and keratinocytes in the mouse skin model with a near-infrared multiphoton laser-scanning microscope (NIR-MPLSM). Stratum corneum (SC) and viable epidermal thickness measured with MPLSM was found in close agreement with conventional histology. LCs were located in the vertical plane at a mean depth of 14.9 mum, less than 3 mum above the dermo-epidermal boundary and with a normal histogram distribution. This likely corresponds to the fact that LCs reside in the suprabasal layer (stratum germinativum). The nuclear volume of keratinocytes was found to be approximately 1.4 times larger than that of resident LCs (88.6 mum3). Importantly, the ratio of LCs to keratinocytes in mouse ear skin (1:15) is more than three times higher than that reported for human breast skin (1:53). Accordingly, cross-presentation may be more significant in clinical Gene Gun applications than in pre-clinical mouse studies. These interspecies differences should be considered in pre-clinical trials using mouse models.

Vehicle effects on the in vitro penetration of testosterone through equine skin

The effects of three vehicles, phosphate-buffered saline (PBS), ethanol (50% in PBS w/w) and propylene glycol (50% in PBS w/w) on in vitro transdermal penetration of testosterone was investigated in the horse. Skin was harvested from the thorax of five Thoroughbred horses after euthanasia and stored at -20 degrees C until required. The skin was then defrosted and placed into Franz-type diffusion cells, which were maintained at approximately 32 degrees C by a water bath. Saturated solutions of testosterone, containing trace amounts of radiolabelled [C-14]testosterone, in each vehicle were applied to the outer (stratum corneum) surface of each skin sample and aliquots of receptor fluid were collected at 0, 2, 4, 8, 16, 20, 22 and 24 h and analysed for testosterone by scintillation counting. The maximum flux (J(max)) of testosterone was significantly higher for all sites when testosterone was dissolved in a vehicle containing 50% ethanol or 50% propylene glycol, compared to PBS. In contrast, higher residues of testosterone were found remaining within the skin when PBS was used as a vehicle. This study shows that variability in clinical response to testosterone could be expected with formulation design.

The cellular response to transglutaminase-cross-linked collagen

Collagen, type I, is a highly abundant natural protein material which has been cross-linked by a variety of methods including chemical agents, physical heating and UV irradiation with the aim of enhancing its physical characteristics such as mechanical strength, thermal stability, resistance to proteolytic breakdown, thus increasing its overall biocompatibility. However, in view of the toxicity of residual cross-linking agents, or impracticability at large scales, it would be more useful if the collagen could be cross-linked by a milder, efficient and more practical means by using enzymes as biological catalysts. We demonstrate that on treating native collagen type I (from bovine skin) with both tissue transglutaminase (TG2; tTG) and microbial transglutaminase (mTG; Streptoverticillium mobaraense) leads to an enhancement in cell attachment, spreading and proliferation of human osteoblasts (HOB) and human foreskin dermal fibroblasts (HFDF) when compared to culture on native collagen. The transglutaminase-treated collagen substrates also showed a greater resistance to cell-mediated endogenous protease degradation than the native collagen. In addition, the HOB cells were shown to differentiate at a faster rate than on native collagen when assessed by measurement of alkaline phosphatase activity and osteopontin expression. © 2005 Elsevier Ltd. All rights reserved.

Photonic skin for pressure and strain sensing

In this paper, we report on the strain and pressure testing of highly flexible skins embedded with Bragg grating sensors recorded in either silica or polymer optical fibre. The photonic skins, with a size of 10cm x 10cm and thickness of 1mm, were fabricated by embedding the polymer fibre or silica fibre containing Bragg gratings in Sylgard 184 from Dow Corning. Pressure sensing was studied using a cylindrical metal post placed on an array of points across the skin. The polymer fibre grating exhibits approximately 10 times the pressure sensitivity of the silica fibre and responds to the post even when it is placed a few centimetres away from the sensing fibre. Although the intrinsic strain sensitivities of gratings in the two fibre types are very similar, when embedded in the skin the polymer grating displayed a strain sensitivity approximately 45 times greater than the silica device, which also suffered from considerable hysteresis. The polymer grating displayed a near linear response over wavelength shifts of 9nm for 1% strain. The difference in behaviour we attribute to the much greater Young's modulus of the silica fibre (70 GPa) compared to the polymer fibre (3 GPa).

Polymer photonic sensing skin

A highly flexible sensing skin with embedded polymer optical fibre Bragg gratings is characterised The response to pressure and strain compare favourably to a similar skin instrumented with silica fibre Bragg grating sensors.

An ethnopharmacological approach to multidrug -resistant Staphylococcus aureus: Evaluation of Italian plants used in the traditional healing of skin disease

One-third of botanical remedies from southern Italy are used to treat skin and soft tissue infections (SST's). Methicillin-resistant Staphylococcus aureus (MRSA), a common cause of SSTIs, is responsible for increased morbidity and mortality from infections. Therapeutic options are limited by antibiotic resistance. Many plants possess potent antimicrobial compounds for these disorders. Validation of traditional medical practices is important for the people who rely on medicinal plants. Moreover, identification of novel antibiotics and anti-pathogenic agents for MRSA is important to global healthcare.^ I took an ethnopharmacological approach to understand how Italian medicinal plants used for the treatment of SSTIs affect MRSA growth and virulence. My hypothesis was that plants used in folk remedies for SSTI would exhibit lower cytotoxicity and greater inhibition of bacterial growth, biofilm formation and toxin production in MRSA than plants used for remedies unrelated to the skin or for plants with no ethnomedical application. The field portion of my research was conducted in the Vulture-Alto Bradano area of southern Italy. I collected 104 plant species and created 168 crude extracts. In the lab, I screened samples for activity against MRSA in a battery of bioassays. Growth inhibition was analyzed using broth microtiter assays for determination of the minimum inhibitory concentration. Interference with quorum-sensing (QS) processes, which mediate pathogenicity, was quantified through RP-HPLC of δ-toxin production. Interference with biofilm formation and adherence was assessed using staining methods. The mammalian cytotoxicity of natural products was analyzed using MTT cell proliferation assay techniques.^ Although bacteriostatic activity was limited, extracts from six plants used in Italian folk medicine (Arundo donax, Ballota nigra, Juglans regia, Leopoldia comosa, Marrubium vulgare, and Rubus ulmifolius ) significantly inhibited biofilm formation and adherence. Moreover, plants used to treat SSTI demonstrated significantly greater anti-biofilm activity when compared to plants with no ethnomedical application. QSI activity was evident in 90% of the extracts tested and extracts from four plants ( Ballota nigra, Castanea saliva, Rosmarinus officinalis, and Sambucus ebulus) exhibited a significant dose-dependent response. Some of the plant remedies for SSTI identified in this study can be validated due to anti-MRSA activity.^

Effects of Endothelin 3 on the Tumor-Angiogenic Response in a Novel Melanoma Mouse Model

Skin cancer is the most common form of cancer in the United States. Melanoma is a particular type of skin cancer, which arises from the malignant transformation of melanocytes and generally exhibits a high propensity to metastasize. Melanoma progression is dependent on angiogenesis to deliver the oxygen and nutrients required to maintain the altered metabolism of rapidly proliferating tumorigenic cells. Recent studies have implicated the growth factor Endothelin 3 (Edn3) in melanoma progression and metastasis. The aim of this study was to examine the role that Edn3 plays in the angiogenesis of melanocytic lesions. For this purpose, Dct-Grm1 transgenic mice, which spontaneously acquire melanocytic lesions through the aberrant expression of the metabotropic glutamate receptor 1 (mGluR1), were crossed with K5-Edn3 transgenic mice that overexpress Edn3. Tumors in the Dct-Grm1/K5-Edn3 experimental population were examined and compared to the control Dct-Grm1 population using immuno-fluorescent staining targeted against the vascular endothelial cell marker CD31. Proteomic arrays were also used and identified changes in the expression of specific angiogenic factors. CD31 antibody staining results revealed an increased vascular density in Dct-Grm1/K5-Edn3 tumors compared with tumors from the Dct-Grm1 controls. Analysis of the relative expression of angiogenic proteins showed an upregulation of various vascular factors in tumors from the Dct-Grm1/K5-Edn3 population, including VEGF-B, MMP-8, MMP-9, and Angiogenin. These results suggest that endothelin signaling promotes angiogenesis in melanocytic lesions. Targeting the factors upregulated by Edn3 signaling may prove effective in hindering melanoma progression.

UVB radiation generates sunburn pain and affects skin by activating epidermal TRPV4 ion channels and triggering endothelin-1 signaling.

At our body surface, the epidermis absorbs UV radiation. UV overexposure leads to sunburn with tissue injury and pain. To understand how, we focus on TRPV4, a nonselective cation channel highly expressed in epithelial skin cells and known to function in sensory transduction, a property shared with other transient receptor potential channels. We show that following UVB exposure mice with induced Trpv4 deletions, specifically in keratinocytes, are less sensitive to noxious thermal and mechanical stimuli than control animals. Exploring the mechanism, we find that epidermal TRPV4 orchestrates UVB-evoked skin tissue damage and increased expression of the proalgesic/algogenic mediator endothelin-1. In culture, UVB causes a direct, TRPV4-dependent Ca(2+) response in keratinocytes. In mice, topical treatment with a TRPV4-selective inhibitor decreases UVB-evoked pain behavior, epidermal tissue damage, and endothelin-1 expression. In humans, sunburn enhances epidermal expression of TRPV4 and endothelin-1, underscoring the potential of keratinocyte-derived TRPV4 as a therapeutic target for UVB-induced sunburn, in particular pain.

Specific humoral response of hosts with variable schistosomiasis susceptibility

The schistosome blood flukes are some of the largest global causes of parasitic morbidity. Further study of the specific antibody response during schistosomiasis may yield the vaccines and diagnostics needed to combat this disease. Therefore, for the purposes of antigen discovery, sera and antibody-secreting cell (ASC) probes from semi-permissive rats and sera from susceptible mice were used to screen a schistosome protein microarray. Following Schistosoma japonicum infection, rats had reduced pathology, increased antibody responses and broader antigen recognition profiles compared with mice. With successive infections, rat global serological reactivity and the number of recognized antigens increased. The local antibody response in rat skin and lung, measured with ASC probes, increased after parasite migration and contributed antigen-specific antibodies to the multivalent serological response. In addition, the temporal variation of anti-parasite serum antibodies after infection and reinfection followed patterns that appear related to the antigen driving the response. Among the 29 antigens differentially recognized by the infected hosts were numerous known vaccine candidates, drug targets and several S. japonicum homologs of human schistosomiasis resistance markers-the tegument allergen-like proteins. From this set, we prioritized eight proteins that may prove to be novel schistosome vaccine and diagnostic antigens.