Effects of Smoking Versus Nonsmoking on Postprandial Glucose Metabolism in Heavy Smokers Compared With Nonsmokers.

OBJECTIVE: Epidemiological studies suggest that smoking increases the risk of type 2 diabetes. We hypothesized that smoking-derived nicotine and ensuing activation of nicotinic cholinergic receptors in the gastrointestinal tract and the autonomic nervous system would have a detrimental effect on postprandial glucose metabolism and, thus, potentially constitute a link between smoking and the development of type 2 diabetes. RESEARCH DESIGN AND METHODS: We subjected 11 male heavy smokers to two identical 4-h liquid mixed-meal tests: one with concomitant cigarette smoking (immediately before and after meal intake) and one without smoking. Twelve age-, sex-, and BMI-matched nonsmokers underwent an identical meal test without smoking. RESULTS: The smokers were characterized by higher fasting plasma concentrations of glucagon compared with the nonsmokers. Among smokers, cigarette smoking before and after the meal significantly reduced postprandial plasma glucose excursions. There were no differences in gut or pancreatic hormone concentrations between the test days in the smoking group, and the responses were similar to those in the control group. CONCLUSIONS: Our results suggest that smoking in association with meal intake decreases the postprandial plasma glucose concentrations, possibly through decreased gastric emptying, and that elevated fasting glucagon concentrations rather than smoking-induced alterations in postprandial glucose and hormone responses may be associated with the elevated risk of type 2 diabetes in chronic smokers.

A randomized side-by-side study comparing alexandrite laser at different pulse durations for port wine stains.

BACKGROUND AND OBJECTIVES: Pulsed dye laser (PDL) represents the gold-standard treatment for port wine stains (PWS). However, approximately 20% of patients are poor responders and yield unsatisfactory end-results. The Alexandrite (Alex) laser may be a therapeutic alternative for selected PWS subgroups, but optimal laser parameters are not known. The aim of this study was to assess clinical PWS clearance and safety of Alex laser at a range of pulse durations. MATERIALS AND METHODS: Sixteen individuals (14 previously PDL-treated) with deep red (n = 4), purple macular (n = 5) and purple hypertrophic (n = 7) PWS were included. Four side-by-side test areas were marked within each lesion. Three test areas were randomized to Alex laser at pulse durations of 3, 5, or 10 ms (8 mm spot, DCD 60/40), while the fourth was untreated. The lowest effective fluence to create purpura within the entire test spot was titrated and applied to intervention areas. Standardized clinical photographs were taken prior to, immediately after laser exposure and at 6-8 weeks follow up. Clinical PWS clearance and laser-related side effects were assessed using clinical photos. RESULTS: Alex laser at 3, 5, and 10 ms pulse durations demonstrated significant clearance compared to untreated controls (P < 0.001). Three milli second pulse duration exhibited improved clearance versus 5 ms (P = 0.016) and 10 ms (P = 0.004), while no difference between five and 10 ms was shown (P = 0.063). Though not significant, good responders (>50% clearance) were more likely to have purple hypertrophic PWS (5/7) compared to purple macular (2/5) and deep red lesions (1/4). Eight laser-exposed test areas (17%) developed hypopigmented atrophic scarring. Side effects tended to be more frequently observed with 5 ms (n = 4) and 10 ms (n = 3) versus 3 ms pulse duration (n = 1). Correspondingly, 3 ms was associated with a superior (n = 6) or comparable (n = 10) overall cosmetic appearance for all individuals. CONCLUSION: Alex laser at 3 ms pulse duration offers superior clinical clearance and safety compared to 5 and 10 ms, and seems best suited for purple hypertrophic PWS. Treatment should be restricted to experienced personnel due to a particularly narrow therapeutic window. Lasers Surg. Med. 49:97-103, 2017. © 2016 Wiley Periodicals, Inc.

Copper hypersensitivity.

The world production of copper is steadily increasing. Although humans are widely exposed to copper-containing items on the skin and mucosa, allergic reactions to copper are only infrequently reported. To review the chemistry, biology and accessible data to clarify the implications of copper hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common. As a metal, it possesses many of the same qualities as nickel, which is a known strong sensitizer. Cumulative data on subjects with presumed related symptoms and/or suspected exposure showed that a weighted average of 3.8% had a positive patch test reaction to copper. We conclude that copper is a very weak sensitizer as compared with other metal compounds. However, in a few and selected cases, copper can result in clinically relevant allergic reactions.

Increased expression of glucagon-like peptide-1 receptors in psoriasis plaques.

Recent case reports suggest that treatment with glucagon-like peptide-1 (GLP-1) agonists results in clinical improvement of psoriasis. The purpose of this study was to determine whether GLP-1 receptors (GLP-1Rs) are found in the skin of healthy volunteers and psoriasis patients and if so, whether GLP-1Rs are located on keratinocytes or immune cells. Three mm-punch skin biopsies were taken for gene expression analysis from six healthy volunteers and from affected and unaffected skin of six psoriasis patients. In addition, a blood sample was obtained from all participants. Cultured human keratinocytes were either untreated or incubated with tumor necrosis factor- α (TNF-α), interferon-γ (IFN-γ) or a combination of TNF-α and IFN-γ for 48 h. Total RNA was extracted from all the samples, reversely transcribed and analysed for the expression of GLP-1R using real-time PCR. Gene expression analysis showed expression of GLP-1Rs in five of six skin biopsies from psoriasis plaques, in one of six biopsies from unaffected psoriatic skin and in one of six biopsies from healthy skin. GLP-1R expression was found in the blood of both healthy volunteers and psoriasis patients. No GLP-1R expression was found in either stimulated or unstimulated cultured human keratinocytes. Our results show increased presence of GLP-1Rs in psoriasis plaques and that this most likely is due to infiltration with immune cells. This offers a possible explanation for the positive effect of treatment with GLP-1R agonists in patients with psoriasis.

Second-degree burns caused by exposure to sunbed with displaced filter in the facial tanner: a report of two cases.

Sunbed exposure frequently leads to erythema of the skin but second-degree burns are unusual. We report two patients who experienced second-degree burns due to partial displacement of the filter in the facial tanner of a sunbed. This is a severe fault and calls for increased safety regulations.

[The sweet Christmas rash]. / Den søde julekløe

Christmas tree hypersensitivity is a rare condition, which has so far obtained scarce attention in the medical literature. We present two clinical cases of hypersensitivity associated with Christmas tree exposure, a 51-year-old woman with allergic contact dermatitis and a 41-year-old man with allergic rhinitis. The female patient had a positive patch test reaction to colophony, and the male patient had a positive skin prick test reaction to alternaria mould. Both were successfully advised to avoid prolonged exposure to Christmas trees and buy artificial trees for Christmas.

Lasers or light sources for treating port-wine stains.

BACKGROUND: Port-wine stains are birthmarks caused by malformations of blood vessels in the skin. Port-wine stains manifest themselves in infancy as a flat, red mark and do not regress spontaneously but may, if untreated, become darker and thicker in adult life. The profusion of various lasers and light sources makes it difficult to decide which equipment is the best for treating port-wine stains. OBJECTIVES: To study participant satisfaction, clinical efficacy, and adverse effects of the treatment of port-wine stains by lasers and light sources. SEARCH METHODS: We searched the following databases up to April 2010: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (Clinical Trials) in The Cochrane Library, MEDLINE (from 2005), EMBASE (from 2007), LILACS (Latin American and Caribbean Health Science Information database, from 1982), and reference lists of articles. We also searched online trials registries for ongoing trials and contacted trial authors where appropriate. SELECTION CRITERIA: Randomised clinical trials (RCTs) of lasers or light sources for the treatment of port-wine stains. DATA COLLECTION AND ANALYSIS: Our outcomes of interest were participant satisfaction, reduction in redness of the port-wine stain as determined by clinical evaluation, and short- and long-term adverse effects of the treatments. Three authors independently extracted data and assessed trial quality. MAIN RESULTS: We included 5 RCTs involving a total of 103 participants; all of the trials used a within-participant design. The interventions and outcomes were too varied to be combined statistically. All trials used the pulsed dye laser for comparisons.None of the studies focused on participant satisfaction, which was one of our primary outcomes, but participant preference was evaluated in three of five studies. Participants preferred the pulsed dye laser to intense pulsed light based on the clinical effect. They marginally preferred the Neodymium:YAG (yttrium-aluminium-garnet) (Nd:YAG) laser to the pulsed dye laser due to shorter lasting purpura, and pulsed dye laser in conjunction with cooling was preferred to treatment with pulsed dye laser alone.All trials examined short-term efficacy of less than six months after treatments with the pulsed dye laser, intense pulsed light, and Nd:YAG laser. The pulsed dye laser was evaluated in all five trials. Depending upon the setting of the pulsed dye laser, this resulted in more than 25% reduction in redness. This was after 1 to 3 treatments for up to 4 to 6 months postoperatively in 50% to 100% of the participants. There was only one study each of intense pulsed light and Nd:YAG laser.Two trials had no occurrence of long-term adverse effects, i.e. six months after treatment. Three trials reported pigmentary alterations in 3% to 24% of the participants, with the highest percentage occurring in Chinese participants with darker skin types. In one study one participant experienced scarring of the skin caused by a too-high dose of the laser used. Short-term side-effects included pain, crusting, and blistering in the first two weeks after treatment. AUTHORS' CONCLUSIONS: The pulsed dye laser leads to clinically relevant clearance of port-wine stains. A limited number of RCTs evaluated the efficacy from intense pulsed light and other laser types. High-quality RCTs are needed to assess individual efficacy from different lasers and light sources, as well as participant satisfaction.

Gastric bypass surgery: improving psoriasis through a GLP-1-dependent mechanism?

Psoriasis is a common inflammatory skin disease and obesity constitutes a risk factor for the disease. Obese patients with psoriasis are often more difficult to treat and are at increased risk for dyslipidemia, diabetes, hypertension and cardiovascular disease. Case reports suggest that gastric bypass surgery in patients with psoriasis may result in complete remission of the disease. A substantial weight loss is achieved in the months following surgery, which is likely to reduce psoriasis symptoms and risk of comorbidities. Interestingly, however, it has been described that improvement of psoriasis is initiated immediately following surgery before any weight loss could have happened. We hypothesize that the glucose-lowering gut incretin hormone glucagon-like peptide-1 (GLP-1) is responsible for this effect. The levels of GLP-1 have been shown to increase up to 20 times after gastric bypass surgery. This most likely contributes importantly to the acute remission of type 2 diabetes, which is often induced by gastric bypass operations. The hormone is not hypersecreted after the purely restrictive bariatric procedure gastric banding and no case reports exist on improvement in psoriasis following gastric banding. Intriguingly, recent studies describe that GLP-1 may convey anti-inflammatory effects in addition to its effects on glucose homeostasis. Also, GLP-1 reduces appetite and gastrointestinal motility including gastric emptying, which reduces food intake and leads to weight loss. Thus, both a direct anti-inflammatory effect of GLP-1 as well as an indirect effect through weight loss could contribute to improvement in psoriasis. A potential involvement of GLP-1 in the remission of psoriasis observed after bariatric surgery offers exciting possibilities for research and eventually perhaps new ways of anti-psoriatic treatment.

Metal allergen of the 21st century--a review on exposure, epidemiology and clinical manifestations of palladium allergy.

Consumers are mainly exposed to palladium from jewellery and dental restorations. Palladium contact allergy is nearly always seen together with nickel allergy, as palladium and nickel tend to cross-react. We aimed to analyse the available palladium patch test data and case reports to determine whether the prevalence of palladium mono-sensitization has increased. Based on available patch test data from the period 1986-2008, a total of 10 778 patients were patch tested with palladium chloride. The median prevalence of palladium allergy was 7.8% (range <1.0-19.0%) in dermatitis patients and 7.4% (range 1.3-13.9%) in dental patients. The median prevalence of palladium mono-sensitization (defined as the presence of palladium allergy and the absence of nickel allergy) was 0.2% (range 0-1.6%) in dermatitis patients and 0.5% (range 0-7.2%) in dental patients. A slight increase in the prevalence of palladium mono-sensitization was observed over the study period. We conclude that clinically relevant palladium allergy should mainly be suspected in patients who present with allergic contact granulomas at sites of piercing, but also in patients who have clinical disease and palladium patch test reactivity without concomitant nickel reactivity. Palladium salts should be included in dental screening patch test series. Palladium use in jewellery should be limited until we know more about the risk of sensitization.

Role of tumor necrosis factor-α in the regulation of keratinocyte cell cycle and DNA repair after ultraviolet-B radiation.

Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine produced in the skin in response to ultraviolet B radiation (UVB). TNF-α facilitates UVB-induced apoptosis and probably contributes to removal of damaged cells. Surprisingly, murine TNF-α-knockout models have demonstrated that TNF-α is necessary for the early stages of skin carcinogenesis and development of squamous cell carcinoma. In the present PhD thesis, we examined the effects of TNF-α on DNA repair and cell cycle regulation in UVB-irradiated keratinocytes. In the model of premalignant keratinocytes (HaCaT), TNF-α abolished the UVB-induced G2/M checkpoint and diminished the DNA repair despite induction of apoptosis. TNF-α activated the protein kinase B/Akt and regulation of its downstream targets, mTOR, Bad and FoxO3a. This effect was dependent on atypical protein kinase C species (aPKC) since a specific peptide blocking the activity of the PKCξ and ι/λ abrogated the activation of Akt by TNF-α. The aPKC-Akt axis was likely to be responsible for the TNF-α-induced decrease in DNA repair since blocking of Akt activity restored DNA repair. Since anti-TNF-α approaches are increasingly used in the therapy of autoimmune diseases and one of the safety concerns is the potential enhancement of skin carcinogenesis, we investigated the effect of the chimeric monoclonal anti-TNF-α antibody infliximab on UVB-irradiated HaCaT cells. Cells treated with infliximab had significantly increased levels of DNA damage despite enhanced G2/M checkpoint arrest, increased apoptosis and inhibition of Akt. In conclusion, we identified a possible novel mechanism by which TNF-α promotes UVB-induced skin carcinogenesis. This depends on aPKC-Akt activation and inhibition of DNA repair. TNF-α-treated cells are prone to escape checkpoint control and are possibly more likely to accumulate mutations, which may constitute a relevant mechanism enhancing tumor development. The effect of anti-TNF-α therapy on skin carcinogenesis warrants further investigation as our study indicates that, in contrast to what had been expected, infliximab may impair DNA repair.

Sun protection factor persistence on human skin during a day without physical activity or ultraviolet exposure.

BACKGROUND/PURPOSE: Recently, we showed that the sun protection factor (SPF) decreases by a constant factor to reach 55% during a day with activities. Organic sunscreens but not inorganic ones are absorbed through the skin. We wished to determine the SPF decrease caused by absorption by investigating the difference in SPF decreases between an organic and an inorganic sunscreen, assuming that the sunscreens are stable, and that the SPF decrease is time dependent if caused by absorption. METHODS: Sunscreens were used on the backs of 22 participants, who were physically inactive at 22 degrees C. SPF testing was performed 30 min, 4, and 8 h after application of 2 mg/cm(2) sunscreen. Whether cream evaporation changed the ultraviolet (UV) transmission was studied in vitro. RESULTS: The SPFs of the organic and inorganic sunscreens were reduced by about 25% after 8 h. Evaporation of the cream did not cause a change in UV transmission in vitro. CONCLUSION: A similar decrease in SPF of the organic and inorganic sunscreen was seen during 8 h without activities, and is thus not likely to be caused by absorption or evaporation from the skin. The SPF decrease after 8 h is about 55% when the participants perform activities and 25% without activities. TRIAL REGISTRATION: Registered at http://www.clinicaltrials.gov. Register name: 'Sunscreen: Persistence of Sun Protection Factor and the Influence on Vitamin D'. Register number H-B-2007-120.

Sun protection factor persistence during a day with physical activity and bathing.

BACKGROUND/PURPOSE: The persistence of sunscreens during a day with physical activity and bathing is often debated. We wished to examine the durability of the protection achieved by one sunscreen application. METHODS: Seven areas were marked on the back of 24 volunteers. One area was phototested to determine UV sensitivity. Six areas were treated with either an organic or an inorganic sunscreen (2 mg/cm2). The participants performed physical activities, were exposed to a hot environment and bathing during 8 h and were phototested with ultraviolet-B (UVB) radiation 30 min, 4 and 8 h after sunscreen application. The minimal erythema dose (MED) was determined 24 h after irradiation. The sun protection factor (SPF) was calculated, as MED on protected skin/MED on unprotected skin. RESULTS: The SPFs of the inorganic and organic sunscreen, respectively, were reduced by 38% and 41% after 4 h and by 55% and 58% after 8 h. CONCLUSION: One application of either an inorganic or an organic sunscreen reduced the erythema caused by UVB during a day with physical activity and bathing. After 8 h the sunscreens still provided approximately 43% of the initial protective effect. This might simulate what happens during a day at the beach.

Industry-supported meta-analyses compared with meta-analyses with non-profit or no support: differences in methodological quality and conclusions.

BACKGROUND: Studies have shown that industry-sponsored meta-analyses of drugs lack scientific rigour and have biased conclusions. However, these studies have been restricted to certain medical specialities. We compared all industry-supported meta-analyses of drug-drug comparisons with those without industry support. METHODS: We searched PubMed for all meta-analyses that compared different drugs or classes of drugs published in 2004. Two authors assessed the meta-analyses and independently extracted data. We used a validated scale for judging the methodological quality and a binary scale for judging conclusions. We divided the meta-analyses according to the type of support in 3 categories: industry-supported, non-profit support or no support, and undeclared support. RESULTS: We included 39 meta-analyses. Ten had industry support, 18 non-profit or no support, and 11 undeclared support. On a 0-7 scale, the median quality score was 6 for meta-analyses with non-profit or no support and 2.5 for the industry-supported meta-analyses (P < 0.01). Compared with industry-supported meta-analyses, more meta-analyses with non-profit or no support avoided bias in the selection of studies (P = 0.01), more often stated the search methods used to find studies (P = 0.02), searched comprehensively (P < 0.01), reported criteria for assessing the validity of the studies (P = 0.02), used appropriate criteria (P = 0.04), described methods of allocation concealment (P = 0.05), described methods of blinding (P = 0.05), and described excluded patients (P = 0.08) and studies (P = 0.15). Forty percent of the industry-supported meta-analyses recommended the experimental drug without reservations, compared with 22% of the meta-analyses with non-profit or no support (P = 0.57).In a sensitivity analysis, we contacted the authors of the meta-analyses with undeclared support. Eight who replied that they had not received industry funding were added to those with non-profit or no support, and 3 who did not reply were added to those with industry support. This analysis did not change the results much. CONCLUSION: Transparency is essential for readers to make their own judgment about medical interventions guided by the results of meta-analyses. We found that industry-supported meta-analyses are less transparent than meta-analyses with non-profit support or no support.

Synergistic effect of broad-spectrum sunscreens and antihistamines in the control of idiopathic solar urticaria.

BACKGROUND: It can be difficult to provide patients with idiopathic solar urticaria adequate protection from sunlight. In a nonrandomized controlled trial, we used a standardized phototest procedure to determine the effects of using sunscreen and antihistamine to control idiopathic solar urticaria. OBSERVATIONS: Three patients with idiopathic solar urticaria underwent phototesting with UV-B and UV-A radiation. The minimal urticarial dose (MUD) was determined 15 minutes after irradiation. The patients were subsequently tested with 5 times the MUD, and the reaction was graded every minute for 15 minutes. The patients were then treated with a high-protection, broad-spectrum sunscreen and a nonsedative antihistamine alone and in combination and underwent similar phototesting. The use of sunscreen allowed the patients to tolerate much higher doses of UV radiation (32-38 times the MUD on untreated skin). Antihistamine use did not increase the patients' MUD but did suppress wheal formation and itch, and only immediate erythema sharply located in the irradiated areas occurred. The combination of sunscreen and antihistamine acted synergistically and increased the tolerance to UV radiation markedly (80-267 times the MUD on untreated skin). Conclusion High-protection, broad-spectrum sunscreens and antihistamines protect patients with solar urticaria in different ways and are highly effective when combined.

TNF-alpha stimulates Akt by a distinct aPKC-dependent pathway in premalignant keratinocytes.

Tumor necrosis factor-alpha (TNF-alpha) is an important proinflammatory cytokine involved in the pathogenesis of inflammatory skin diseases and cutaneous squamous cell carcinoma. Some of these effects are mediated by the stimulatory effect of this cytokine on the Akt signalling pathway, which renders keratinocytes less susceptible to proapoptotic stimuli and enhances cell growth. We have recently shown that TNF-alpha-induced Akt activation may promote the early stages of skin cancer. In this work, we demonstrate that in the premalignant keratinocyte cell line HaCaT, TNF-alpha activates Akt, ERK1/2 and p38. The specific peptide blocking the activity of the atypical protein kinase C (aPKC) species zeta and iota/lambda abrogated the effects of TNF-alpha on Akt and ERK1/2 but increased the activation of p38. The TNF-alpha-dependent phosphorylation of Akt-ERK1/2 was slightly decreased by NF kappaB inhibition and in the presence of p38 blockers. Akt/ERK signalling but not p38 activation was abolished in the presence of the iron chelator desferroxamine that blocks formation of hydroxyl ( OH) radicals. Thus, the TNF-alpha signalling in keratinocytes seems to bifurcate into an aPKC-, NFkB- and OH-dependent pathway resulting in the activation of survival and mitogenic pathways mediated by Akt and ERK1/2, and a signalling pathway conveyed by p38 that contributes to Akt activation but is suppressed by aPKC. Our data may be utilized in the development of more selective anti-TNF-alpha therapeutic strategies.

Infliximab inhibits DNA repair in ultraviolet B-irradiated premalignant keratinocytes.

Anti-tumor necrosis factor-alpha (TNFalpha) approaches are increasingly used in the therapy of autoimmune diseases. One of the safety concerns is the potential enhancement of skin carcinogenesis. The aim of this study was to investigate if the TNFalpha neutralizing antibody, infliximab, directly affects the cell cycle and DNA repair in premalignant human keratinocytes after ultraviolet-B (UVB) irradiation. We found that infliximab-treated cells exhibited an enhanced G2/M cell cycle arrest and increased apoptosis after 10-20 mJ/cm(2) UVB. In spite of this, the level of cyclobutane pyrimidine dimers (CPD) in infliximab-treated cells was significantly increased at both 24 and 48 h after irradiation with 10 mJ/cm(2) UVB. As we have recently shown that protein kinase B/Akt is involved in the TNFalpha signalling pathway and promotes cell survival and skin carcinogenesis, we measured activatory phosphorylations of Akt (Ser-473 and Thr-308) and the signalling via related pathways Erk 1/2, p38 and p70-S6K. Infliximab inhibited Akt and its downstream targets p70-S6K and Erk 1/2, and stimulated p38 both in sham-irradiated and UVB-irradiated cells. In conclusion, despite the fact that infliximab blocks Akt and stimulates the G2/M checkpoint and apoptosis in UVB-irradiated keratinocytes, the repair of CPD is impaired. It is conceivable that anti-TNFalpha treatments may contribute to the accumulation of mutagenic lesions in the epidermis and enhance the early stages of skin carcinogenesis.

Epidermal stem cells - role in normal, wounded and pathological psoriatic and cancer skin.

In this review we focus on epidermal stem cells in the normal regeneration of the skin as well as in wounded and psoriatic skin. Furthermore, we discuss current data supporting the idea of cancer stem cells in the pathogenesis of skin carcinoma and malignant melanoma. Epidermal stem cells present in the basal layer of the interfollicular epidermis and in the bulge region of the hair follicle play a critical role for normal tissue maintenance. In wound healing, multipotent epidermal stem cells contribute to re-epithelization. It is possible that defects in growth control of either epidermal stem cells or transit amplifying cells constitute a primary pathogenetic factor in the epidermal hyperproliferation seen in psoriasis. In cutaneous malignancies mounting evidence supports a stem cell origin in skin carcinoma and malignant melanoma and a possible existence of cancer stem cells.

Topical corticosteroids in the treatment of acute sunburn: a randomized, double-blind clinical trial.

OBJECTIVE: To examine the effect of topical corticosteroid treatment on acute sunburn. DESIGN: Randomized, double-blind clinical trial. SETTING: University dermatology department. PATIENTS: Twenty healthy volunteers with Fitzpatrick skin types I (highly sensitive, always burns easily, tans minimally) through III (sun-sensitive skin, sometimes burns, slowly tans to light brown). INTERVENTION: Seven 34-cm(2) areas were marked on the upper aspect of the back of each participant. An untreated area was tested to determine UV sensitivity. Two areas were treated with excess amounts (2 mg/cm(2)) of either a moderate-potency corticosteroid or a high-potency corticosteroid 30 minutes before UV-B exposure as controls. Six or 23 hours after exposure to radiation, the remaining areas were treated with the 2 corticosteroid preparations. MAIN OUTCOME MEASURES: The sunburn improvement factor (SIF) was determined by the following equation: SIF = MED (minimal erythema dose) on treated skin/MED on nontreated skin. An SIF greater than 1 indicated an effect of topical corticosteroids in sunburn relief. RESULTS: The SIFs in the areas treated with either topical corticosteroid 30 minutes before UV-B exposure or high-potency corticosteroid 6 hours after UV-B exposure were significantly different from SIFs in areas that received no treatment (SIF 1.1-1.7; P < .05). Only the median SIF of 1.7 in the areas treated with high-potency corticosteroid 30 minutes before UV-B exposure was clinically relevant. The areas treated 23 hours after UV-B exposure and the areas treated with a moderate-potency corticosteroid 6 hours after UV-B exposure showed no significant reduction in redness. CONCLUSION: Treatment with topical moderate-potency or high-potency corticosteroids does not provide a clinically useful decrease in the acute sunburn reaction when applied 6 or 23 hours after UV exposure.

TNF-alpha impairs the S-G2/M cell cycle checkpoint and cyclobutane pyrimidine dimer repair in premalignant skin cells: role of the PI3K-Akt pathway.

Tumor necrosis factor-alpha (TNF-alpha) is induced by UVB radiation and has been implicated in the early stages of skin carcinogenesis. Here, we show that in normal keratinocytes and the transformed keratinocyte cell lines, HaCaT and A431, TNF-alpha stimulates protein kinase B/Akt, which results in activation of the survival complex mTORC1 (mammalian target of rapamycin complex 1) and inhibition of the proapoptotic proteins Bad and FoxO3a. In UVB-irradiated HaCaT cells (10-20 mJ cm(-2)), TNF-alpha increased the proportion of cycling cells and enhanced the rate of apoptosis. A significantly higher proportion of UVB-treated HaCaT cells containing unrepaired cyclobutane pyrimidine dimers (CPDs) escaped the G2/M cell cycle checkpoint in the presence of TNF-alpha (9.5+/-3.3 vs 4.8+/-2.2%). After treatment with the PI3K inhibitor LY294002, only 1.2+/-0.7% of CPD-containing HaCaT cells were actively cycling. TNF-alpha enhanced apoptosis less potently and did not increase the level of CPD or stimulate cell cycle progression in normal keratinocytes. Our data suggest that TNF-alpha overrides the G2/M checkpoint in premalignant skin cells and allows for some cells containing unrepaired CPD to enter the cell cycle. The effect of TNF-alpha seems to be dependent on Akt activation and may constitute a relevant mechanism enhancing mutagenesis and tumor development.