FS03.7Tape stripping procedure: influence of anatomic site, application pressure, duration and removal

Background and Objectives:  Tape stripping is a common method for investigating stratum corneum (SC) physiology as well as bioavailability and bioequivalence of topical drugs. However, little is known concerning the influence of procedures (anatomic site, pressure, pressure duration, tape removal rate) inherent in each stripping protocol.
Methods:  Tape stripping was performed using tapes on the forearm, forehead and back. On the forearm different pressures (165 and 330 g cm⁻²), durations of pressure (2s and 10s), and removal rate (slow and rapid removal) was performed. Changes in skin physiology were evaluated by measurement of transepidermal water loss (TEWL) and hydration.
Results:  A significant influence of all parameters on the TEWL‐increase as a function of tape strip number was observed. The fastest increase was demonstrated on the forehead, followed by the back and, lastly, the forearm. Rapid removal produced a protracted increase in comparison to the slow removal. 10s pressure induced a faster increase of TEWL than 2s pressure. Likewise, the 330 g cm⁻² pressure induced an earlier increase than the 165 g cm⁻². Skin hydration was not influenced by the variables tested.
Conclusion:  Tape stripping results are influenced dramatically by all investigated parameters. A standardized procedure is necessary for a comparable study design. A dynamic SC stress test to more closely investigate SC cohesion is proposed based on the present observations.     

Skin and systemic pharmacokinetics of tacrolimus following topical application of tacrolimus ointment in adults with moderate to severe atopic dermatitis

Background  Systemic exposure to tacrolimus following topical application of tacrolimus ointment is minimal. There are, however, no data on the distribution of tacrolimus in the skin.
Objectives  To assess the distribution of tacrolimus in the skin and the systemic pharmacokinetics of tacrolimus in adults with moderate to severe atopic dermatitis after first and repeated application of tacrolimus ointment.
Methods  We investigated skin distribution of topically applied tacrolimus and systemic pharmacokinetics of percutaneously absorbed tacrolimus in adults with atopic dermatitis after topical application of tacrolimus 0·1% ointment twice daily for 2 weeks. Tacrolimus concentrations were assessed in full-thickness skin biopsies and blood samples.
Results  Of 14 patients, 11 completed treatment and were analysed. Mean ± SD tacrolimus concentrations in the skin at 24 h after first and last ointment applications were 94 ± 20 and 595 ± 98 ng cm⁻³, respectively. At 168 h after stopping treatment, values were 97% lower than at 24 h after last application. Tacrolimus concentration decreased with increasing skin depth. Systemic tacrolimus exposure after ointment application was low and highly variable, with 31% of samples below the limit of quantification (0·025 ng mL⁻¹) and 94% below 1 ng mL⁻¹. Blood concentrations at 24 h after the first and last ointment applications were 750 and 1800 times lower, respectively, than those in skin. Physicians' assessments showed that tacrolimus ointment was effective and well tolerated.
Conclusions  Tacrolimus was primarily partitioned in the skin, with minimal systemic absorption after topical application, in patients with atopic dermatitis.     

Release of nickel from coins and deposition onto skin from coin handling--comparing euro coins and SEK

Background:  Nickel exposure is the most common cause of contact allergy. The role of contact with nickel-containing coins has been controversial.
Objectives:  To compare the release of nickel from 1 and 2 EUR coins (both composed of two alloys: Cu 75%, Zn 20%, Ni 5% and Cu 75%, Ni 25%) and Swedish 1 SEK coin (alloy: Cu 75%, Ni 25%) and to assess the deposition of nickel onto skin by coin handling.
Methods:  Nickel release was determined by immersion in artificial sweat (2 min, 1 hr, 24 hr, and 1 week). Deposition of nickel onto the skin was assessed in three subjects after 1-hr handling of 2 EUR and 1 SEK coins. Samples ( n  = 48) were taken from fingers and palms by acid wipe sampling and analysed by inductively coupled plasma mass spectrometry.
Results:  Amounts of nickel released by 1 week from 1 SEK, 1 EUR, and 2 EUR coins were 121, 86, and 99 μg/cm², respectively. Corresponding 2 min values were 0.11, 0.25, and 0.22 μg/cm². Nickel was deposited onto the skin by 1 hr coin handling (range 0.09–4.1 μg/cm²), the largest amounts were on fingers; similar amounts of nickel were deposited from 1 SEK and 2 EUR coins.
Conclusions:  Nickel is released from 1 and 2 EUR and 1 SEK coins at similar amounts. Nickel is deposited onto skin at substantial and similar amounts by coin handling. Acid wipe sampling is suitable for studies of skin exposure to nickel and in risk assessment.     

Characterization of the mechanical properties of a dermal equivalent compared with human skin in vivo by indentation and static friction tests

Background/aims: The study of changes in skin structure with age is becoming all the more important with the increase in life. The atrophy that occurs during aging is accompanied by more profound changes, with a loss of organization within the elastic collagen network and alterations in the basal elements. The aim of this study is to present a method to determine the mechanical properties of total human skin in vivo compared with dermal equivalents (DEs) using indentation and static friction tests.
Methods: A new bio-tribometer working at a low contact pressure for the characterization the mechanical properties of the skin has been developed. This device, based on indentation and static friction tests, also allows to characterize the skin in vivo and reconstructed DEs in a wide range of light contact forces, stress and strain.
Results: This original bio-tribometer shows the ability to assess the skin elasticity and friction force in a wide range of light normal load (0.5–2 g) and low contact pressure (0.5–2 kPa). The results obtained by this approach show identical values of the Young's modulus E ^* and the shear modulus G ^* of six DEs obtained from a 62-year-old subject ( E ^*=8.5±1.74 kPa and G ^*=3.3±0.46 kPa) and in vivo total skin of 20 subjects aged 55 to 70 years ( E ^*=8.3±2.1 kPa, G ^*=2.8±0.8 kpa).     

Iontophoretic delivery of terbinafine in onychomycosis: a preliminary study

Background  Onychomycosis is a common disease; topical treatment is usually poorly effective, while systemic treatment is more effective but may be associated with side-effects. Iontophoretic drug delivery may improve drug penetration through the nail and lead to better therapeutic results.
Objectives  To evaluate the efficacy, safety and tolerability of topical treatments with terbinafine HCl delivered with or without an iontophoretic patch in patients with onychomycosis of the toenails.
Methods  Patients enrolled into the study were divided randomly into two groups. Group A was treated with terbinafine and an iontophoretic patch (at a constant current density of 100 μA cm⁻²). Group B was treated with terbinafine without iontophoresis. Treatment was overnight wear, every day, 5 days per week, for 4 weeks. Follow-up period was 8 weeks from the end of treatment.
Results  A significant clinical response was recorded in patients of group A (active group). The percentage of patients having healthy toenail growth of more than 1·5 mm at the end of treatment was 40% compared with 11% in patients treated with terbinafine without current (passive group). The percentage of patients having fungal elements (KOH) in nail specimens decreased significantly at 8 weeks following the completion of treatment: 16% in the active group vs. 53% in the passive group. Patients in the active group reported a tingling sensation that is expected when using an iontophoretic drug delivery treatment.
Conclusions  The delivery of terbinafine under an electrical current of 100 μA cm⁻² appears to be efficacious and safe and is well tolerated for the treatment of nail onychomycosis.     

Mitigation of acute ultraviolet B radiation-mediated damages by baicalin in mouse skin

Background: Solar ultraviolet (UV) irradiation, in particular UVB with a wavelength range between 290 and 320 nm, induces different hazardous effects on the skin, including sunburn, photoaging and cancer. Protection against sun-induced damage is therefore a highly desirable goal. Chemoprevention is being investigated as a potential approach for the management of UV damages including skin cancer.
Aim: In this study, to determine the relevance of our in vitro findings to in vivo situations, we assessed the effects of baicalin on UVB-mediated damages in mice skin.
Methods: Balb/C hairless mice were topically pretreated (24 h before UVB) or post-treated (5 min after UVB) with baicalin (1 mg/cm² skin area/mouse/100 μl acetone) and were exposed to UVB 24 h later (180 mJ/cm²). The animals were sacrificed 1 and 24 h after the UVB exposure. Skin edema, histopathology changes, hydrogen peroxide (H₂O₂) and cyclobutane pyrimidine dimers (CPDs)-positive cells were assessed to determine the UVB-induced photodamage.
Results: Our data demonstrated that a topical application of baicalin, either as a pretreatment or as a post-treatment, resulted in a significant decrease in UVB mediated increases in skin edema, skin hyperplasia and infiltration of leukocytes. Further, baicalin treatments (pre and post) also resulted in a significant decrease in UVB mediated (1) generation of H₂O₂ and (2) formation of DNA photolesions: CPDs.
Conclusion: Based on these data, we suggest that baicalin could be developed as an agent for the management of conditions elicited by UV exposure including skin cancer.     

Nicotinamide and its metabolite N-methylnicotinamide increase skin vascular permeability in rats

Background.  It has been suggested that topically applied nicotinamide and its metabolite N- methylnicotinamide (NMN⁺) might be useful agents for treatment of dermatological disorders such as acne vulgaris and rosacea.
Aim.  This study aimed to find out if the mechanism of these therapeutic effects depends on their vascular effects, by investigating if nicotinamide and NMN⁺ are able to influence vascular permeability of the vessels in the skin on the back of Wistar rats.
Methods and results.  A dose-dependent increase in vascular permeability was seen in rats treated intradermally with nicotinamide and NMN⁺. Interestingly, a significantly stronger effect of NMN⁺ compared with nicotinamide was evident. Increased vascular permeability in rats treated with 0.5% NMN⁺ ointment was seen. Moreover, indomethacin, a cyclo-oxygenase 1 and 2 inhibitor and N ^G-nitro- l -arginine methyl ester ( l -NAME), a nitric oxide (NO) synthase inhibitor, reduced the observed effects of nicotinamide and NMN⁺.
Conclusions.  This study provides direct in vivo evidence that nicotinamide and its metabolite NMN⁺ increase skin vascular permeability in rats by a mechanism that may involve NO and prostaglandins.     

Frequency of sensitization to methyl aminolaevulinate after photodynamic therapy

Background:  Allergic contact dermatitis to methyl aminolaevulinate (Metvix™) after topical application in photodynamic therapy (PDT) has previously been described in case reports.
Objective:  To compare the frequency of sensitization to Metvix^® cream in a group of patients previously treated at least five times with Metvix-PDT with the frequency observed in an unexposed control group.
Methods:  Twenty patients treated five times or more with Metvix-PDT and 60 controls with no prior exposure to Metvix^® were patch tested with Metvix^® cream and Metvix^® placebo cream. Subsequently, the patients were interviewed to determine the relevance of a positive patch test reaction to Metvix^®.
Results:  Of 20 patients treated with Metvix-PDT, 7 were sensitized to Metvix^® cream, giving a sensation risk of 35%. In the control group, 1 of 60 became sensitized after a single exposure to Metvix^® cream (1.7%). There was no reaction to the placebo cream. The positive patch tests to Metvix^® were considered relevant in four of seven patients (57%).
Conclusions:  This study demonstrates a considerable risk of sensitization after Metvix-PDT. We suggest that the patients are interviewed to detect late or persistent local reactions after PDT. These reactions are often considered to be local infections but may represent allergic contact dermatitis, and therefore, patients should be offered patch testing with Metvix^® cream.     

Immunohistochemical expression of matrix metalloproteinases in photodamaged skin by photodynamic therapy

Background  Photodynamic therapy (PDT) has been described for photoageing treatment, but its mechanism of action is not clarified. Although PDT-induced matrix metalloproteinase (MMP) expression and collagen production have been studied in normal skin and in inflammatory disease, there is no report about the effect of PDT on the extracellular matrix in photodamaged skin.
Objectives  To evaluate skin remodelling induced by methyl aminolaevulinate (MAL)-PDT in photodamaged skin by histological and immunohistochemical studies.
Methods  Fourteen patients were treated with two sessions of MAL-PDT. The light source was a light-emitting diode (635 nm, 37 J cm⁻²). Skin biopsies were performed in all patients before and at 3 and 6 months after treatment. Immunohistochemical studies evaluated collagen types I and III, MMP-1, MMP-3, MMP-7, MMP-9, MMP-12 and tissue inhibitor of metalloproteinases-1.
Results  Global improvement in photodamaged skin was observed. A significant increase in expression of MMP-9 in the dermis was detected at 3 months after treatment ( P  =   0·002). Significant increases in the expression of collagen type I at 3 months ( P  =   0·002) and at 6 months after treatment ( P  =   0·001) were also observed.
Conclusions  Skin remodelling induced by MAL-PDT was demonstrated in photodamaged skin. Two sessions of MAL-PDT increases immunohistochemical expression of MMP-9 in the dermis at 3 months after treatment, and also of collagen type I.     

Hair removal with the long-pulse alexandrite and long-pulse Nd:YAG lasers is safe and well tolerated in children

Background.  Children with excessive hair may have severe psychological consequences. Laser hair removal in adults is known to be safe and well tolerated, but this is less well established in children.
Objective.  To describe our experience with laser hair removal in children, and to investigate the safety and tolerability of this procedure in children.
Methods.  The case records of 24 children aged < 16 years, who had received a minimum of three treatments for hair removal were analysed retrospectively. For patients with Fitzpatrick skin phototype II–IV, the lasers used were a long-pulse alexandrite (755 nm) with either continuous chilled-air cooling at fluences of 16–27 J/cm² or a long-pulse alexandrite with cryogen cooling at fluences of 16–32 J/cm². For patients with Fitzpatrick skin phototype IV–VI, lasers used were a long-pulse Nd:YAG (1064 nm) with a chilled contact sapphire tip at fluences of 20–35 J/cm² or a long-pulse Nd:YAG with cryogen cooling at fluences of 16–26 J/cm².
Results.  Mean age at first treatment was 12.3 years. Diagnoses were constitutional hirsutism (14 patients), polycystic ovarian syndrome (five), congenital melanocytic naevus (two), generalized hypertrichosis (two) and naevoid hypertrichosis (one). One patient required a general anaesthetic, eight required topical anaesthetic cream, and 15 did not require any form of anaesthesia. Intolerable discomfort requiring adjustment in fluence was the only recorded side-effect, affecting two cases. There were no incidences of blistering, infection, dyspigmentation or scarring.
Conclusion.  When administered appropriately, laser hair removal is safe and well tolerated in children aged < 16 years.     

Imaging of melanin distribution using multiphoton autofluorescence decay curves

Background/purpose: Multiphoton fluorescence lifetime imaging (FLIM) is a technique that produces an image based on differences in the decay rate of fluorescence from a sample. Based on this method, the DermaInspect was developed to observe human skin components non-invasively. In this study, we used the DermaInspect to study melanin in skin.
Methods: A human three-dimensional skin model containing melanocytes was embedded in an OCT compound, frozen and sectioned at 10 μm. The melanin distribution in each section was visualized by the DermaInspect using time-resolved single-photon counting and near-infrared femtosecond laser pulse excitation. The melanin distribution of the same sections was then visualized using the Fontana-Masson staining method.
Results: High-resolution images were generated from the ratio of a ₁/ a ₂ ( a ₁e^{− t /120}+ a ₂e^{− t /1100} was chosen to express the exponential fluorescent decay curve) obtained using the DermaInspect. Granules with a high a ₁/ a ₂ ratio, approximately 1 μm in diameter, were observed. Fontana-Masson staining identified these granules as melanin. This new technique was then applied for in vivo observation of melanin in human skin. 'Melanin caps' were visualized in the basal cell layer around the nuclei in images derived from the a ₁/ a ₂ ratio.
Conclusion: Our study confirms that FLIM can non-invasively provide data of the melanin distribution with almost the same quality as the conventional Fontana-Masson staining method, and demonstrates that FLIM is useful for in vivo observation of melanin granules in human skin.     

Systematic administration of chloroquine in discoid lupus erythematosus reduces skin lesions via inhibition of angiogenesis

Background.  Discoid lupus erythematosus (DLE) is a chronic cutaneous form of lupus erythematosus, characterized by inflammation and scarring skin lesions, with lymphocyte infiltration and vasodilation. Antimalarial drugs have beneficial therapeutic effects in DLE, partially resulting from their immunomodulating and photoprotective properties. The possible influence of these drugs on angiogenesis has not been previously evaluated.
Aims.  To investigate the impact of chloroquine (CQ) treatment on the expression of vascular endothelial growth factor (VEGF, a major regulator of angiogenesis) and CD34 (a transmembrane glycoprotein expressed on endothelial cells and involved in tethering lymphocytes) in patients with DLE.
Methods.  A 3-mm skin biopsy was taken from typical skin lesions in 10 people with DLE. Another biopsy was taken from the same area after 3 months of treatment with CQ (250 mg/day). Skin sections were stained with monoclonal antibodies directed against VEGF and CD34. The intensity of epidermal VEGF expression, and the number and area of CD34-positive dermal blood vessels were assessed.
Results.  CQ treatment induced a reduction in epidermal VEGF expression. It also resulted in a significant decrease in the median number of CD34+ dermal blood vessels (from 219 to 125 vessels per mm²). Furthermore the median vessel area was significantly lowered from 9.76 × 10⁶ to 6.92 × 10⁶ mm² per mm² of the dermis.
Conclusions.  These results indicate that one beneficial effect of CQ treatment in DLE may be due to its antiangiogenic properties.     

Modern tattoos cause high concentrations of hazardous pigments in skin

Background:  Modern tattoo colourants frequently consist of azo pigments that not only contain multiple impurities but also are originally produced for car paint and the dyeing of consumer goods.
Objective:  In order to be able to assess the health risk of tattoos, it is important to determine the pigment concentration in human skin.
Methods:  We tattooed excised pigskin and human skin with a common tattoo pigment (Pigment Red 22) under various conditions. After tattooing, we quantitatively extracted the pigment in order to determine the pigment concentration in skin.
Results:  The concentration of pigments ranged from about 0.60 to 9.42 mg/cm² of tattooed skin (mean value 2.53 mg/cm²) depending upon the size of the pigment crystals, the pigment concentration applied to the skin surface, and the respective procedure of tattooing.
Conclusion:  In conclusion, high concentrations of colourants are injected into the skin during tattooing and based upon this quantification, a risk assessment of tattooing ought to be carried out.     

Methylaminolaevulinate-based photodynamic therapy of Bowen's disease and squamous cell carcinoma

Background  Photodynamic therapy (PDT) with methylaminolaevulinate (MAL) is an approved noninvasive treatment option for actinic keratosis and Bowen's disease (BD), two precursors of invasive squamous cell carcinoma (SCC).
Objectives  To assess efficacy, prognostic features, tolerability and cosmetic outcome of MAL-PDT for the treatment of BD and SCC.
Methods  In total, 112 biopsy-proven lesions of BD and SCC in 55 subjects were treated in an outpatient setting. MAL cream (160 mg g⁻¹) was applied for 3 h prior to illumination with a light-emitting diode source (wavelength range 635 ± 18 nm; light dose 37 J cm⁻²). A second MAL-PDT session was given 7 days later. Complete response rate at 3 months after the last treatment, recurrence rate at the 24-month follow-up, and cosmetic outcome were recorded.
Results  The overall complete response rates were 73·2% at 3 months and 53·6% at 2 years. Clinical thickness, atypia and lesion depth were significant predictors of the response at 3 months when using a univariate analysis ( P  <   0·001). A multivariate logistic regression model, with robust variance estimation, showed that cell atypia was the only statistically significant independent predictor of the treatment outcome at 3 months.
Conclusions  MAL-PDT may represent a valuable, effective and well tolerated treatment option with good cosmetic outcome for superficial, well-differentiated (Broders' scores I and II) BD and microinvasive SCC. In contrast, its use for superficial SCCs with a microinvasive histological pattern and for nodular, invasive lesions, particularly if poorly differentiated keratinocytes are present (Broders' scores III and IV), should be avoided.     

Efficacy of three different laser wavelengths for in vitro wound healing

Background and objective: Despite contradictory reports on the effect of laser light on cell proliferation, studies have shown that appropriate doses and wavelengths of laser light are therapeutically beneficial in tissue repair and pain control. This study aimed to establish if the dose and/or wavelength influenced the biological responses of irradiated in vitro fibroblasts – 1 h after laser irradiation.
Materials and methods: This study aimed to establish cellular responses of normal and wounded human skin fibroblasts to helium-neon (632.8 nm), diode (830 nm) and Nd:YAG (1064 nm) laser irradiation using one exposure of 5 or 16 J/cm² on day 1 and again on day 4.
Results: Wounded cells exposed to 5 J/cm² using 632.8 nm showed an increase in cell migration and haptotaxis, a stable increase in the release of interleukin-6 (IL-6), a decrease in caspase 3/7 activity, an increase in ATP viability and an increase in cell proliferation – 1 h after the final exposure. The results confirm that changes in parameters such as ATP viability, cytokine expression (IL-6), cell proliferation (alkaline phosphatase enzyme activity) and DNA damage can be observed directly after the laser irradiation. The amount of DNA damage and cytotoxicity may be related to duration of the laser irradiation, which is dependent on the power density (mW/cm²) of each laser.
Conclusion: The results indicate that 5 J/cm² using 632.8 nm results in a stimulatory effect that is more effective than 830 and 1064 nm. The results suggest possible mechanisms by which the wavelength may potentially influence the cellular responses of wounded cells.     

Photodynamic therapy of actinic keratoses with 8% and 16% methyl aminolaevulinate and home-based daylight exposure: a double-blinded randomized clinical trial

Background  Photodynamic therapy (PDT) is an effective but time-consuming and often painful treatment for actinic keratosis (AK). Home-based daylight–PDT has the potential to facilitate treatment procedure and to reduce associated pain due to continuous activation of small amounts of porphyrins. Moreover, a reduced methyl aminolaevulinate (MAL) concentration may reduce associated inflammation, making the treatment more tolerable for the patients.
Objectives  To compare response rates and adverse effects after PDT using conventional 16% and 8% MAL with home-based daylight exposure in treatment of AK.
Methods  Thirty patients with mostly thin-grade AK of the face or scalp were treated with 16% and 8% MAL–PDT in two symmetrical areas after application of sunscreen. Immediately after, patients left the hospital with instructions to spend the remaining day outside at home in daylight. Patients scored pain during treatment and light exposure was monitored with an electronic wristwatch dosimeter.
Results  The complete response rate after 3 months was 76·9% for 16% MAL and 79·5% for 8% MAL ( P  = 0·37). Patients spent a mean of 244 min outdoors and received a mean effective light dose of 30 J cm⁻². Light doses of 8–70 J cm⁻² induced similar response rates ( P  = 0·25). Patients experienced mild to moderate pain during daylight exposure (mean maximal pain score of 3·7). No differences in pain scores and erythema were seen between the areas treated with 16% MAL and with 8% MAL.
Conclusions  Home-based daylight-mediated MAL–PDT was an effective and well-tolerated treatment for AK. No differences in response rates or adverse events were found between the areas treated with 16% MAL and with 8% MAL.     

Susceptibility of dermatophyte isolates obtained from a large worldwide terbinafine tinea capitis clinical trial

Background  Our group, in collaboration with seven other laboratories, has recently developed a method to determine the susceptibility of dermatophytes.
Objectives  The objective of this study was to determine the terbinafine susceptibility profile of dermatophyte isolates obtained from patients with tinea capitis enrolled in two large worldwide clinical trials and to investigate whether these susceptibilities differ by geographical location.
Methods  Susceptibilities were determined according to the Clinical and Laboratory Standards Institute M38-A2 standard.
Results  From a total of 978 baseline dermatophyte isolates, we selected 301 isolates at random. These included: Trichophyton tonsurans ( n  = 125) , Microsporum canis ( n  = 94), T. violaceum ( n  = 63) and M. audouinii ( n  = 19) . The terbinafine minimum inhibitory concentration (MIC) range was 0·001–0·25 μg mL⁻¹, while MIC₅₀ and MIC₉₀ ranged between 0·002 and 0·125 μg mL⁻¹ and 0·03 and 0·25 μg mL⁻¹, respectively, for all species tested. MIC₅₀ and MIC₉₀ varied by individual species; however, there was no difference in terbinafine MIC among the different species isolated from U.S. and non-U.S. sites.
Conclusion  Terbinafine demonstrates potent antifungal activity against dermatophyte isolates obtained from patients with tinea capitis worldwide.     

Two possible classifications of facial skin type by two parameters in Korean women: sebum excretion rate (SER) and skin surface relief (SSR)

Background/alms: Worldwide there are many skin care and makeup products intended to maintain good appearance or youthful skin. However consumers don't know which products are suitable for their skin because they don't know their skin type exactly. To solve this problem, this study suggests two possible classifications of facial skin type by using simple methods.
Methods: In 662 healthy volunteers, sebum excretion rate (SER) on the forehead and cheek, and skin surface patterns on the cheek were examined by using Sebutape® and skin replica, respectively.
Results: The measured SER values from the forehead were 0.06-4.56 ng/cm²/min and those from the cheek were 0.04-3.80 ng/cm²/min. From these data, five facial skin types were classified by SER: low SER type, medium SER type, high SER type, combination-1 SER type, and combination-2 SER type. Twelve facial skin types were also classified; they were determined by star formation (SF), primary lines (PL), secondary lines (SL) and pore size from magnified skin surface relief (SSR) of the cheek.
Conclusions: From this study, we suggest new classifications of skin types by SER and SSR. The SER and the parameters of skin surface texture (SF, PL, and SL) decreased with age and the pore size increased with age. Although these methods did not classify facial skin types perfectly, we were able to check consumer's facial skin types simply and more quickly.     

Thioredoxin upregulation by 5-aminolaevulinic acid-based photodynamic therapy in human skin squamous cell carcinoma cell line

Background/purpose: 5-aminolaevulinic acid-based photodynamic therapy (ALA-PDT) is widely performed in the clinical setting for superficial skin cancers, giving favorable results, but residual tumor and recurrence occur occasionally. Thioredoxin is a common antioxidant that suppresses apoptosis and facilitates cell growth. We investigated the expression of thioredoxin following ALA-PDT in human skin squamous cell carcinoma cell line, HSC-5.
Methods: ALA-PDT was performed in HSC-5 cells using low-dose (5 J/cm², 100 mW/cm²) or high-dose (30 J/cm², 100 mW/cm²) irradiation, and the expression of thioredoxin was measured by Western blotting. An MTT assay was used to assess cell growth following a low dose of multiple irradiations. Cell death was examined by Western blotting for caspase-3 and PARP. Immunofluorescence double staining using annexin V and propidium iodine was also performed.
Results: Expression of thioredoxin was only observed following low-dose exposure ALA-PDT. Multiple low-dose exposure ALA-PDT significantly proliferated cell growth. With high-dose exposure ALA-PDT, caspase-3 and PARP expression were seen, and cell death due to apoptosis and/or necrosis was observed, but thioredoxin was barely detected.
Conclusion: Low-dose exposure ALA-PDT increased the expression of thioredoxin and facilitated the growth of HSC-5 cells.