Temperature dependence of photochemical fluorescence fading in Skh-1 hairless mouse collagen

Background: Type I mammalian collagens have several photolabile fluorescent moieties that absorb UV rays capable of reaching the dermis. We studied the temperature dependence of fluorescence fading as a marker of photochemical damage.
Methods: Collagen solutions were exposed to radiation from 0 to 240 min from either a UVG-11 hand lamp, total dose=1.173 × 10³ J/m²; a UVL-21 hand lamp total dose=2.030 × 10³ J/m²; or the fluorometer, at 325±5 nm, total dose=0.156 × 10³ J/m². We recorded intensities at excitation/emission wavelengths 270/300, 270/330, 270/360, 270/400, 325/400, and 370/450 nm at T =9.0–59.3 °C.
Results: Results indicated simultaneous forward and reverse reactions. However, the 270/360 nm fluorophore could be analyzed as a second-order reaction. The Arrhenius curve showed two straight lines intersecting near the denaturation temperature, with helix activation energy E _a∼0 and coil E _a=7.6±0.6 kcal/mol (31.7±2.5 kJ/mol).
Discussion: Collagen-bound fluorophores are not just passive markers of oxidative stress and age-related damage. Their photolability to wavelengths reaching the dermis may result in pathological conditions, particularly at elevated body temperatures.     

Colorimetry provides a rapid objective measurement of de novo hair growth rate in mice

Background: Depilated mice have been used as a test platform for hair growth-regulating agents. However, currently available assessment tools for hair growth in mice are less than ideal.
Methods: Tristimulus colorimetry of the fur color of depilated agouti, albino, and black mice with L ^*, a ^*, and b ^* values were performed daily until the full growth of pelage. Using light-emitting diode (LED) irradiation (650 and 890 nm) with a daily dose of 3.5 J/cm² as hair growth regulators, the hair growth rates observed by the global assessment were compared with those derived from colorimetry.
Results: In contrast to a ^* and b ^* values, L ^* values changed more drastically over time in the anagen phase regardless of fur color. Unlike the inhibitory effect of 650 nm irradiation, LED of 890 nm promoted de novo hair regrowth in mice. The difference in hair growth rates detected by colorimetry paralleled the observation made by the global assessment.
Conclusion: The L ^* value of fur color obtained by tristimulus colorimetry was a sensitive yet quantitative indicator of de novo hair growth, and could be used to project the hair growth rate in mice.     

Quantitation of epidermal and mucosal tissue injury using contrast agents and imaging techniques

Background/purpose: Epidermal injury is common but the accuracy of visual methods is significantly impacted by the inherent skin pigmentation. We examined imaging and fluorescence techniques to quantify tissue injury as a function of skin color.
Methods: Epidermal and mucosal scratches were created in 20 light- ( L ^* 68.2±2.3) and 20 dark-skinned ( L ^* 46.4±5.2) females. Injured and uninjured sites were treated with toluidine blue (TB), fluorescein (FL) and a TB/FL mixture and photographed under conditions of white and fluorescent light. Area and intensity parameters were determined.
Results: Injured sites with TB and TB/FL had higher areas than the control for both light and dark subjects ( anova , P <0.05). The intensity of the injured TB site was higher than the control for light skin only. The areas of injured sites with FL and TB/FL were higher than the control for both groups as were the intensities of the injured sites with FL. The findings were similar for the lip skin.
Conclusions: Application of TB and FL contrasts under white and fluorescent light can be used to quantify tissue injuries for L ^* values >35 and is a promising approach for the quantitation across a range of skin pigmentation.     

Migration and penetration of a fluorescent textile dye into the skin –in vivo versus in vitro methods

Abstract:  The amount of textile dye migration from the textile and penetration into the skin is relevant when assessing the risk of textile dyes. In this paper, in vivo methods were developed using a harmless textile dye with a strong fluorescence and were then compared with in vitro methods. For the in vivo method, the textile was applied to the lower back of six volunteers wearing the textile 12 h and to the lower back of 12 volunteers during 30 min active sport. The maximum skin absorption of 55 ± 17 ng/cm² was obtained in the group engaged in sports. The in vitro methods, which involved the application of the textile to the pig ear skin, was shown to yield similar results to the 12 h in vivo group (31.2 ± 9.6 ng/cm² vs 27 ± 14 ng/cm²). The migration of the textiles into artificial sweat resulted in approximately 20  μ g/cm². The disadvantage of such textile extract applications on pig ear skin is discussed. It could be demonstrated that the absorption of the dye is strongly correlated to the amount of sweat, whereas the contact time was less important.     

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.     

Dynamic indentation on human skin in vivo: ageing effects

Background/purpose: Knowledge of the mechanical properties of the human skin is very important for cosmetic and clinical research. Objective and quantitative measurements are essential to compare studies performed by different experimenters in different centres. The aim of this paper is to present a method to measure the viscoelastic properties of human skin in vivo using dynamic indentation.
Methods: A complete device to assess the stiffness and damping of skin has been developed. The frequency and strain amplitude range from 10 to 60 Hz and from 1 to 10 μm. Tests on pure elastic inert materials have been performed to validate the device. An in vivo study including dynamic indentation, suction test, hydration measurement and topographic analysis has been performed on 46 subjects aged from 18 to 70 years, divided into three groups.
Results: Results on inert materials show the validity of the device developed. The mechanical behaviour of the skin can be described by a Kelvin–Voight model under dynamic indentation. A comparison with a suction test, hydration and topographic measurements shows that the stiffness and the damping measured by dynamic indentation correspond mainly to the natural tense state of the skin on the body due to the dermis. A weak correlation has been found between dynamic indentation and suction parameters. The complex modulus measured by dynamic indentation at 10 Hz frequency stress ranges from 7.2 ± 2.1 kPa for the oldest group to 10.7 ± 2.6 kPa for the youngest group.
Conclusion: The device presented gives convincing results. The measurement of stiffness and damping complements the viscoelastic phenomenological parameters of the suction test.     

Local tissue water assessed by measuring forearm skin dielectric constant: dependence on measurement depth, age and body mass index

Background: Tissue dielectric constant (TDC) measured at 300 MHz via the coaxial line reflection method is useful to evaluate local tissue water (LTW) and its change. Because excitation field penetration depth depends on size and geometry of the coaxial probe in contact with the skin, TDC values reflect skin and subcutaneous fat to varying depths depending on the probe used. Because tissue changes that occur with age or body mass index (BMI) may affect tissue water content and its depth distribution, our goal was to use TDC measurements to characterize depth patterns of LTW in normal tissue and to investigate the possible impact of age and BMI.
Methods: TDC was measured to depths of 0.5, 1.5, 2.5 and 5.0 mm on both forearms of 69 healthy women (age: 22–82 years, BMI: 18.7–46.1 kg/m²).
Results: Independent of age or BMI, TDC values decreased significantly with increasing measurement depth (33.7±5.8 at 0.5 mm to 21.8±3.7 at 5.0 mm) but at all depths dominant and non-dominant TDC values were similar to each other with ratios ranging from 1.025±0.081 at 0.5 mm to 1.017±0.097 at 5.0 mm. TDC values only at 2.5 and 5.0 mm decreased significantly with increasing BMI whereas TDC values only at 0.5 and 1.5 mm increased significantly with age.
Conclusion: The findings indicate that normal TDC values are affected differentially by BMI and age in a depth-dependent manner. Possible explanations are discussed.     

A numerical-experimental method to characterize the non-linear mechanical behaviour of human skin

Background/aims: Human skin is a complex tissue consisting of several distinct layers. Each layer consists of various components with a specific structure. To gain a better insight into the overall mechanical behaviour of the skin, we wish to study the mechanical properties of the different layers. A numerical-experimental method was developed to characterize the non-linear mechanical behaviour of human dermis.
Methods: Suction measurements at varying pressures were performed on the volar forearm skin of 10 subjects aged 19–24 years old. Deformation of dermis and fat during suction was measured using ultrasound. The experiment was simulated by a finite element model exhibiting extended Mooney material behaviour to account for the non-linear stress–strain relationship. An identification method is used to compare the experimental and numerical results to identify the parameters of the material model.
Results: C _{10, dermis} was found to be 9.4 ± 3.6 kPa and C _{11, dermis} to be 82 ± 60 kPa. A first rough estimate of C _{10, fat} was 0.02 kPa.
Conclusions: The resulting finite element model demonstrated its ability to describe the response of the skin to suction at various pressures. In the future, this method can be used to characterize the mechanical behaviour of different skin layers using various aperture sizes and to characterize the skin behaviour under various loading conditions.     

Mid-infrared spectroscopy on skin using a silver halide fibre probe in vivo

Background/aim: Mid-infrared spectroscopy is a versatile method for in vivo investigation of skin after topical treatment with skin care products.
Methods: FTIR-spectrometer (Bruker Optics) with a flexible silver halide fibre probe (Infrared Fiber Sensors).
Results: Absorbance spectra from 700 to 3000 cm⁻¹ have been recorded to gain information about proteins (amide-I and amide-II vibrations at 1650 and 1550 cm⁻¹), esters (1740 cm⁻¹), carboxylic acid (1710 cm⁻¹), polyalcohols (1050 cm⁻¹) and hydrocarbons (CH _n vibrations at 2800–3000 cm⁻¹).
Conclusions: Using the particular light guide, we were able to measure for the first time the effects of lip care products on lips directly. Furthermore, water binding and glycerol content of the skin could be determined simultaneously, as well as the replenishment of lipids by lipid-enriched bath oil.     

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.     

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.     

Clinical effectiveness and safety experience with alefacept in the treatment of patients with moderate-to-severe chronic plaque psoriasis in Taiwan: results of an open-label, single-arm, multicentre pilot study

Background  The effectiveness and safety of alefacept for the treatment of moderate-to-severe chronic plaque psoriasis has been established in several clinical trials conducted in the United States and Europe. No clinical trial of alefacept has been conducted in Asia.
Objective  To determine the effectiveness and safety of alefacept in the treatment of psoriasis in Chinese population.
Design and methods  This was an open-label, single-arm, multicentre pilot study conducted at three centres. Patients with a body surface area ≥ 10% and psoriasis area and severity Index (PASI) ≥ 12 were given 15 mg alefacept intramuscularly once a week for 12 weeks and were then followed up for a further 12 weeks.
Results  A total of 46 patients was enrolled. Only one subject (2%) achieved a ≥ 75% improvement in PASI at week 14. The median improvement in PASI at week 14 after the 12-week treatment was 39%. At any time during the 6-month course, 3 subjects (7%) achieved a Physician Global Assessment (PGA) of 'almost clear', and a ≥ 50% and ≥ 75% improvement in PASI was seen in 46% and 9%, respectively. There is a trend for decreased counts of CD4⁺ and CD8⁺ cells after alefacept treatment, but subjects who achieved PASI50 showed a lesser degree of decrease in CD4⁺ and CD8⁺ counts compared with those in patients who did not achieve PASI50.
Conclusions  This small pilot study indicated that intramuscular alefacept was effective and safe in psoriasis in Chinese patients over 12 weeks of treatment. Further studies are needed to clarify the reason for low PASI 75 effectiveness and the paradoxical lesser decline of CD4⁺ and CD8⁺ T cells in those who responded.     

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.     

Assessment of the sensitization potential of persulfate salts used for bleaching hair

Background:  Persulfate salts have been associated with both allergic contact dermatitis and bronchial asthma. Because there is currently no experimental data available on the sensitizing properties of persulfate salts (ammonium, sodium, and potassium persulfates), we determined their dermal sensitizing capacity, using the murine local lymph node assay (LLNA).
Material and Methods:  For three consecutive days, BALB/c mice were dermally treated with ammonium, sodium, or potassium persulfate or with the vehicle alone (dimethyl sulfoxide) on each ear (2 × 25 μl). On D6, mice were injected intravenously with [³H]-methyl thymidine. The draining auricular lymph nodes were removed, and the incorporation of [³H]-methyl thymidine was compared with that of vehicle-treated control mice. A stimulation index (SI) relative to the vehicle-treated control value was derived. The sensitizing potency of the chemicals tested was determined by estimating the concentration of chemical required to induce a SI of 3 (EC3).
Results:  All three chemicals provoked positive responses in the LLNA, with dose-dependent increases in proliferation. Maximal SIs recorded were 6.8 ± 1.8, 6.5 ± 1.2, and 5 ± 1.0 at 5% for ammonium, sodium or potassium persulfate, respectively. The EC3 values were 1.9%, 0.9%, and 2.4% for ammonium, sodium, and potassium persulfates, respectively.
Conclusions:  All three persulfate salts need to be considered strong-to-moderate sensitizers according to the murine LLNA.     

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.     

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.     

Application of sunscreen preparations: a need to change the regulations

Background/purpose: To achieve photoprotection indicated on the package of sunscreen products they should be used appropriately. As previously published data documented that people usually applied much less than the recommended dose, the current study was undertaken to assess whether a detailed instruction can improve the use of sunscreens.
Methods: A total of 105 volunteers were asked to apply sunscreen to the whole skin surface in the same way that they would do it before sun exposure. A subgroup of patients ( n =53) were precisely instructed about the proper usage of sunscreens and compared with uninstructed subjects ( n =52). Each tube containing the tested product was weighed before and after application to determine the quantity of the substance, that was used, and to compare it with the recommended dose.
Results: Instructed subjects used significantly more sunscreens (mean 8.6 ± 4.1 g/m²) compared with uninstructed controls (mean 6.8 ± 3.9 g/m², P =0.03). However, both groups used much less of sunscreens than was the recommended amount (i.e. 43.0% and 34.1% of the recommended dose, respectively).
Conclusion: Current regulations about the sunscreen use are inadequate when compared with clinical practice and better standards of photoprotection should be elaborated in the future.     

Repeatability of in vitro measurements of the ultraviolet protection factor (UPF) by spectrophotometry with automatic sampling

Background/aims: Spectrophotometric assessment (in vitro) is the most established method for determining the ultraviolet protection factor (UPF) of textiles. Apart from stringent requirements for measurement precision, practical methods are required for the routine determination of the UPF. We report here spectrophotometric measurements of textiles using a newly developed autosampler. Measurement precision was evaluated under repeatable conditions.
Methods: Fifteen different textiles were spectrophotometrically assessed for the determination of the UPF. Sample handling inside the spectrophotometer was performed with a computer-controlled sampling device, capable of loading and unloading a textile sample from a magazine as well as rotating the sample perpendicular to the spectrometer beam. In order to evaluate the repeatability of measurements, one sample of each textile was assessed eight times under the same conditions in the same laboratory.
Results: A mean percentage of the standard error of 1% [ E ^UPF ] was calculated for the UPF measurements. For UPFs >30, a significantly higher E ^UPF was found ( r =0.78; P <0.001). E ^UV (3.9%) of ultraviolet A (UVA) transmission differed significantly from E ^UV (1.1%) of ultraviolet B (UVB) transmission ( P <0.05).
Conclusions: Though a slight decrease of repeatability was observed for UVA transmission measurements and UPFs higher than 30, our data indicate a high measurement precision under repeatable conditions. In conclusion, spectrophotometric measurements of textiles with the aid of the autosampler presented have been shown to be highly practical, time saving and precise.