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Lauryl Sulphate (lauryl + sulphate)
Kinds of Lauryl Sulphate Selected AbstractsAdsorbing colloid flotation for removal of metal ions in waters from base metal minesENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2002H. Sabti Adsorbing Colloid Flotation (ACF) has been shown in laboratory experiments to be effective for the removal of heavy metals (Zn, Cu, Cd and Pb) from dilute solutions. Sodium dodecyl sulphate (SDS) and sodium oleate (NaOl) were used as surfactants in single or mixed form, with Fe(OH)3 as a flocculant for colloid formation. These reagents worked best for zinc and copper ions for a feed concentration of 50 parts per million (ppm). The removal of lead improved significantly by the use of Fe(OH)3 and NaLS (Sodium lauryl sulphate), while the best removal of cadmium was achieved by the use of Al(OH)3 and HTMABr (hexadecyltrimethylammonium bromide). Flotation experiments were conducted with feed concentrations of 50 and 500 parts per billion (ppb) and 50 ppm (parts per million). The experimental results showed that the residual concentration of metal ions decreased significantly with the decrease in the feed concentration. This could be the effect of excessive (much more than stoichiometric ratio) amounts of surfactant and flocculant, compared to the feed concentrations, required in the effective flotation of dilute feed solutions. The surfactant concentration and feed pH had the largest effects on the process, as observed in the case of cadmium removal. This can be attributed to the flocformation and flotation tendencies of the colloid-metal complexes at various solution pH and surfactant concentrations. The ACF method was applied to a number of natural drainage solutions from the metal mines at Te Aroha, New Zealand, and the experimental results demonstrate that significant removal is achieved for most of the heavy metals. [source] Effect on de novo plaque formation of rinsing with toothpaste slurries and water solutions with a high fluoride concentration (5,000 ppm)EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2009A. Nordström The aim of this study was to evaluate the effect, on de novo plaque formation, of rinsing with toothpaste slurries and water solutions containing a high concentration of fluoride (F). Sixteen subjects rinsed three times per day for 4 d with dentifrice slurries containing 5,000, 1,500, and 500 ppm F, while 12 subjects rinsed with water solutions containing 5,000, 1,500, 500, and 0 ppm F, and 1.5% sodium lauryl sulphate (SLS). Plaque was scored [using the Quigley & Hein index (QHI)] after each 4-d period. Plaque samples for F analysis were collected. Significantly less plaque was scored for the dentifrice slurry containing 5,000 ppm F (buccal and all surfaces) and for 1.5% SLS (buccal surfaces). The differences in plaque scores between dentifrice containing 5,000 and 1,500 ppm F were 19% for all surfaces and 33% for buccal surfaces. The difference between the water solutions containing 1.5% SLS and 1,500 ppm F for buccal surfaces was 23%; the corresponding difference for 5,000 ppm F was 17%. The dentifrice slurry containing 5,000 ppm F accumulated 56% more F in plaque. The combination of high levels of F and SLS in dentifrice reduces de novo plaque formation and increases the accumulation of F in plaque after 4 d. [source] Sodium lauryl sulphate alters the mRNA expression of lipid-metabolizing enzymes and PPAR signalling in normal human skin in vivoEXPERIMENTAL DERMATOLOGY, Issue 12 2009Hans Törmä Abstract:, Detergents irritate skin and affect skin barrier homeostasis. In this study, healthy skin was exposed to 1% sodium lauryl sulphate (SLS) in water for 24 h. Biopsies were taken 6 h to 8 days post exposure. Lipid patterns were stained in situ and real-time polymerase chain reaction (PCR) was used to examine mRNA expression of enzymes synthesizing barrier lipids, peroxisome proliferator-activated receptors (PPAR) and lipoxygenases. The lipid pattern was disorganized from 6 h to 3 days after SLS exposure. Concomitant changes in mRNA expression included: (i) reduction, followed by induction, of ceramide-generating ,-glucocerebrosidase, (ii) increase on day 1 of two other enzymes for ceramide biosynthesis and (iii) persistent reduction of acetyl-CoA carboxylase-B, a key enzyme in fatty acid synthesis. Surprisingly, the rate-limiting enzyme in cholesterol synthesis, HMG-CoA reductase, was unaltered. Among putative regulators of barrier lipids synthesis, PPAR, and PPAR, exhibited reduced mRNA expression, while PPAR,/, and LXR, were unaltered. Epidermal lipoxygenase-3, which may generate PPAR, agonists, exhibited reduced expression. In conclusion, SLS induces reorganization of lipids in the stratum corneum, which play a role in detergents' destruction of the barrier. The changes in mRNA expression of enzymes involved in synthesizing barrier lipids are probably important for the restoration of the barrier. [source] Nanocrystalline Electroplated Cu,Ni: Metallic Thin Films with Enhanced Mechanical Properties and Tunable Magnetic BehaviorADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Eva Pellicer Abstract Nanocrystalline 3,µm thick Cu1,xNix (0.45,,,x,,,0.87) films are electrodeposited galvanostatically onto Cu/Ti/Si (100) substrates, from a citrate- and sulphate-based bath containing sodium lauryl sulphate and saccharine as additives. The films exhibit large values of reduced Young's modulus (173,<,Er,<,192,GPa) and hardness (6.4,<,H,<,8.2,GPa), both of which can be tailored by varying the alloy composition. The outstanding mechanical properties of these metallic films can be ascribed to their nanocrystalline nature,as evidenced by X-ray diffraction, transmission electron microscopy, and atomic force microscopy,along with the occurrence of stacking faults and the concomitant formation of intragranular nanotwins during film growth. Due to their nanocrystalline character, these films also show very low surface roughness (root mean square deviation of around 2,nm). Furthermore, tunable magnetic properties, including a transition from paramagnetic to ferromagnetic behavior, are observed when the Ni percentage is increased. This combination of properties, together with the simplicity of the fabrication method, makes this system attractive for widespread technological applications, including hard metallic coatings or magnetic micro/nano-electromechanical devices. [source] The differences in human cumulative irritation responses to positive and negative irritant controls from three geographical locationsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2008Mingyi W. Trimble A retrospective analysis was conducted to evaluate whether studies from three geographically diverse locations have similar response profiles to the positive and negative controls in a standard 14-day cumulative irritation study. The positive irritant control (0.1% sodium lauryl sulphate) and the negative control (0.9% sodium chloride, saline) data from seventeen 14-day cumulative irritation studies were reviewed. The studies were compiled from three locations representing dry/hot, humid/hot, and dry/cold environments (Scottsdale, Arizona; St Petersburg, Florida; and Winnipeg, Manitoba, respectively). Irritation scores were generated by trained skin graders from a total of 442 subjects studied between 1999 and 2005. Cumulative irritation scores were reviewed and compared between study locations. The irritation scores for the positive and negative controls were not significantly different between locations. Temperature and relative humidity variation did not correlate significantly with overall irritation. However, the dryer climate (i.e. negative or low dew point) had a tendency to induce a higher overall irritation level for both positive and negative controls. [source] Cosmeceutical properties of levan produced by Zymomonas mobilisINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2006K. H. Kim Levan, a polysaccharide that can be produced by both plants and micro-organisms, is a sugar polymer composed of fructose, with-2,6 linkages. Here, we have attempted to assess the possible use of levan produced by Zymomonas mobilis as a cosmeceutical ingredient. In service of this goal, we assessed a host of levan's properties, including its moisturizing effects, cell cytotoxicity, cell proliferation effects and anti-inflammation effects. Levan exhibited a moisturizing effect that was almost exactly the same as that evidenced by hyaluronic acid, as well as a similar cell proliferation effect in human fibroblast and keratinocyte cell lines. Moreover, in our cell proliferation test, which was conducted using bio-artificial skin constructed via 3-dimensional (3-D) culture after the induction of primary skin inflammation with 0.05% sodium lauryl sulphate (SLS), cell viability in the presence of levan (0.01 and 0.05 mg mL,1) was determined to be higher than cell viability in the absence of levan. In our anti-inflammation test, which was also conducted using 3-D artificial skin, and which involved the measurement of a quantity of secreted interleukin-1 (IL-1), a pre-inflammatory mediator induced by SLS, we determined that the quantity of IL-1 in the 3-D artificial skin treated with 0.01 and 0.05 mg mL,1 of levan was less than that registered in a skin sample that had been treated only with SLS. In this study, we determined that levan exerted an anti-inflammatory effect against inflammatory reactions to skin irritants, and also that levan exerted a cell-proliferative effect in bio-artificial skin, thereby indicating its potential applicability as a cosmeceutical agent. [source] A study on the conditioning effects of natural shampoos using the scanning electron microscope*INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2001J. Bellare Synopsis The scanning electron microscope (SEM) was successfully used to study the effects of toiletry treatment with shampoo on the microstructure of hair. This paper describes the use of SEM for comparing the conditioning effects of herbal shampoos. Commercially available herbal shampoos are not completely natural, but contain herbal extracts in a synthetic detergent base, along with other chemical additives. Completely natural shampoos were formulated in the laboratory and their conditioning effects were evaluated by comparing with a commercially available herbal shampoo. The micrographs were studied quantitatively using ,Image Analyser Software' and the extent to which the hair scales were uplifted was measured. The results obtained from the quantitative comparison were in agreement with those obtained from other tests, such as protein loss determination. The damage caused to the hair due to sodium lauryl sulphate was visible in the micrographs. The laboratory formulations were found to be better than the commercially available product. Thus, quantitative measurements from SEM micrographs are a valuable tool to compare the conditioning effects of hair care products. Résumé Le microscope electronique balayant (SEM) est appliqué avec succès a étudier les effets de traitments hygiéniques par shampooing sur le microstucture de cheveux. L'éxposé présent signale l'emploi de SEM a comparer l'effet conditionant des shampoing naturelle (herbacé). Les shampooing herbal de commerce ne sont pas totalement naturelle mais contient extrait de herbe medicinale melangés avec une base de détergent synthetique et d'autres produits chimiques; donc shampooing totalement naturelle a eté formulés dans laboratoire et leurs effets conditionant evalués en comparant avec shampooing herbal (naturelle) de commerce. Les micrographs étaient étudiés quantitativement utilisant ,Image Analyser Software' en mesurant le degré de relèvement de écailes des cheveux. Les résultats obtenues par comparison quantitative sont en accord avec ceux obtenues par d'autres éprevues comme perte de protéine. Le dommage causé aux cheveux par SLS est visible dans les micrographs. Les formulations de laboratoire étaient trouvés meilleurs en comparant avec les produits de commerce. Donc le measure quantitative des micrographs SEM est un outil valable a comparer les effets conditionant de produits hygienique pour cheveux. [source] Influence of a SLS-containing dentifrice on the anti-plaque efficacy of a chlorhexidine mouthrinseJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 3 2004D. A. C. Van Strydonck Abstract Background: Chlorhexidine (CHX) and sodium lauryl sulphate (SLS), the most widely used detergent in dentifrice, may counteract. Consequently, studies about this interaction suggested that care is required when combining both these compounds, even when they are introduced separately into the oral cavity. The purpose of the present study was to investigate the effect of toothbrushing with a SLS-containing dentifrice in one jaw, on the plaque inhibition of a CHX mouthrinse in the opposite jaw during a 4-day study period. Methods: The study was an examiner-blind, randomised two-cell, crossover design. It used a 4-day plaque accumulation model to compare two different oral hygiene regimens with a washout period of 17 days. Sixteen healthy volunteers were enrolled in the study and received a thorough dental prophylaxis at the beginning of each 4-day test period. One jaw (upper or lower) was randomly assigned as the "study" jaw. The opposite jaw was assigned as the "dentifrice" jaw and served only to introduce the effect of brushing with a dentifrice in the study model. Two oral hygiene regimens were evaluated. During one randomly assigned test period, the "dentifrice" jaw was treated by toothbrushing with a 1.5% SLS-containing dentifrice and rinsed together with the "study" jaw with 0.2% CHX, thus forming regimen 1. As a control during the other test period, both the "dentifrice" jaw and "study" jaw were only rinsed with 0.2% CHX, forming regimen 2. No other oral hygiene methods were allowed. After 4 days of undisturbed plaque accumulation, the amount of plaque was evaluated (Silness & Löe 1964). The "study" jaw was used to study the effect of the two regimens on the level of plaque accumulation at the end of the 4-day period. Results: The overall plaque index was 0.36 for regimen 1 and 0.34 for regimen 2. There was no significant difference in plaque accumulation between the two regimens. Conclusions: Within the limitations of the present study design, it can be concluded that ordinary brushing with a 1.5% SLS-containing dentifrice (Colgate Bi-Fluor), followed by rinsing with water does not appear to reduce the level of plaque inhibition offered by a post-brushing CHX rinse. [source] Atopic xerosis: employment of noninvasive biophysical instrumentation for the functional analyses of the mildly abnormal stratum corneum and for the efficacy assessment of skin care productsJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2006Hachiro Tagami MD Summary The subtle dryness of the skin surrounding the lesions of atopic dermatitis (AD) is called atopic dry skin or atopic xerosis (AX). AX is more susceptible to the development of AD skin lesions under various environmental stimuli than the clinically normal skin of the people who have or have had or will have AD, which might be called normal atopic skin (NAS) that shows no functional differences as compared to the skin of normal individuals. Routine histopathologic studies of AX that involve the invasive procedures of biopsy are not so helpful in clarifying the underlying pathogenesis. Modern, noninvasive biophysical instrumentation provides rich and quantitative information about various functional aspects of skin. The stratum corneum (SC) of AX reveals not only decreased hydration but also mildly impaired barrier function demonstrable as an increase in transepidermal water loss, elevated pH values, and an increased turnover rate of the SC consisting of thick layers of smaller-sized corneocytes. These data suggest that AX is related to mildly increased epidermal proliferation as a result of the presence of subclinical cutaneous inflammation. Although AX skin does not display any impairment in the recovery of barrier function after physical skin irritation by tape-stripping, it produces a much more severe, long-lasting inflammatory response together with a delay in barrier repair after chemical irritation such as that induced by sodium lauryl sulphate. The SC of AX is biochemically characterized by reduction in the amounts of ceramides, especially ceramide I, sebum lipids, and water-soluble amino acids. None of these changes in SC functions are seen in NAS, which includes not only the normal-looking skin of AD patients long after regression of all active lesions but also of latent atopic skin such as neonates who later develop AD. This suggests that all of the observed functional as well as biochemical abnormalities of AX are a reflection of subclinical inflammation. The presence of the underlying inflammation in AX also differentiates it from senile xerosis. The mildly impaired SC functions of AX can be improved by daily repeated applications of effective moisturizers, i.e., corneotherapy, which is effective in preventing the exacerbating progression of AX to AD resulting from inadvertent scratching of the skin that facilitates the penetration of environmental allergens into the skin. The biophysical confirmation of such efficacy of moisturizers, including cosmetic bases on the mildly impaired barrier function and decreased water-holding capacity of the SC of AX, definitely substantiates the importance of skin care for the cosmetic skin problems that affect every individual in the cold and dry season ranging from late autumn to early spring. [source] Delayed-type hypersensitivity reactions due to sodium lauryl sulphate in omeprazoleJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 5 2009K Sugiura [source] Incorporation of ceramide 3B in dermatocosmetic emulsions: effect on the transepidermal water loss of sodium lauryl sulphate-damaged skinJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 4 2000Kristien De Paepe Abstract Background In previous work we reported on the efficacy of cosmetic body lotions enriched with skin-identical lipids to reduce the transepidermal water loss (TEWL) of ageing and sodium lauryl sulphate (SLS)-damaged skin. The observations made depended on the experimental design and clearly raised the question of the importance of the galenic formulation of skin ceramide-containing products. Objectives The aim of the present work was to study the different galenic forms in which ceramide 3B (0.2% w/v) can be incorporated into common o/w emulsions. In addition, we investigated whether supplementation of skin care products with ceramide 3B enriched with penetration enhancers and coemulsifiers could exert a beneficial effect on barrier function, done by measuring their effects on the TEWL of SLS-induced scaly skin. Results We found that the technique of incorporating ceramide 3B into the o/w emulsions was important for their final stability. However, no additional positive effect on the TEWL values of SLS-damaged skin could be observed when the efficacy of the ceramide-containing emulsions was compared with that of proper controls. Conclusions Although suitable galenic formulas were developed, no positive effect on TEWL could be observed when ceramide 3B was added in a final concentration of 0.2% (w/v) to different o/w emulsions and applied to SLS-damaged skin. [source] Resonance Rayleigh scattering method for the determination of chitosan with some anionic surfactantsLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 3 2008Yu-Wei Wang Abstract In weak acidic buffer medium, chitosan binding with an anionic surfactant, such as sodium dodecyl benzene sulphonate (SDBS), sodium lauryl sulphate (SLS) or sodium dodecyl sulphonate (SDS), can result in a significant enhancement of resonance Rayleigh scattering (RRS) intensity. The results showed that under optimum conditions the enhanced RRS intensity is proportional to the concentration of chitosan in the range 0.10,20.0 µg/mL for SDBS, 0.27,15.0 µg/mL for SLS and 0.20,15.0 µg/mL for SDS. Among these, the sensitivity of SDBS is the highest and its detection limit for chitosan is 29 ng/mL, while those of SLS and SDS are 83 and 61 ng/mL, respectively. The method has good selectivity and was applied to the determination of trace amounts of chitosan in practical samples with satisfactory results. Therefore, a simple and convenient method with high sensitivity and selectivity for the determination of chitosan was established. Copyright © 2008 John Wiley & Sons, Ltd. [source] Stratum corneum lipids, skin barrier function and filaggrin mutations in patients with atopic eczemaALLERGY, Issue 7 2010J. M. Jungersted To cite this article: Jungersted JM, Scheer H, Mempel M, Baurecht H, Cifuentes L, Høgh JK, Hellgren LI, Jemec GBE, Agner T, Weidinger S. Stratum corneum lipids, skin barrier function and filaggrin mutations in patients with atopic eczema. Allergy 2010; 65: 911,918. Abstract Background:, Prior to the discovery of filaggrin (FLG) mutations, evidence for an impaired skin barrier in atopic dermatitis (AD) has been documented, and changes in ceramide profile, altered skin pH and increased trans-epidermal water loss (TEWL) in patients with AD have been reported. Until now, no studies have analysed stratum corneum (SC) lipids combined with skin barrier parameters in subjects of known FLG genotype. Methods:, A cohort of 49 German individuals genotyped for the most common FLG mutations (R501X, 2282del4) had SC samples taken for lipid analysis by high-performance thin layer chromatography. In addition, TEWL, erythema, skin hydration and pH were measured. In 27 of the 49 individuals, a 24-h irritation patch test with sodium lauryl sulphate was performed. For the analysis, both the AD group and the control group were stratified by FLG mutation status (FLGmut/FLGwt). Results:, In the FLGmut AD group, significantly lower levels of ceramide 4 and significantly higher levels of ceramide 7 were observed when compared to both healthy control groups. However, ceramide 7 levels also significantly differed between FLGwt AD and FLGwt controls, as did ceramide 1 levels. No significant differences were observed for ceramide 2, 3, 5 and 6. FLGmut individuals had significantly higher skin pH values than individuals not carrying FLG mutations. Patients with AD with FLG mutations had significantly higher erythema compared to patients with AD without FLG mutations. Conclusion:, Our results confirm previous observations of altered ceramide levels in AD, which however appear to show no clear relationship with FLG mutations. [source] Sequential application of cold and sodium lauryl sulphate decreases irritation and barrier disruption in vivo in humansBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2005J.W. Fluhr Summary Background, Irritant contact dermatitis (ICD) is one of the most frequent types of occupational dermatitis. Different factors are involved in the development of contact dermatitis. In the food-processing industry, the combined exposure to different irritants may be involved in the development of ICD. Few data have been published regarding the irritant potential of sodium lauryl sulphate (SLS) in combination with cold. Objectives, The present study was intended to analyse whether cold exposure and low skin temperature influence the development of ICD. Methods, Twenty (part I) and 12 (part II) healthy volunteers were exposed twice daily for 4 days to SLS alone, different low temperatures alone (4 °C six times for 90 s with an interval of 20 s or 15 °C for 10 min) or a combination of cold and SLS (19·6 µL SLS 1% cm,2, part I; or 52·6 µL SLS 0·5% cm,2, part II) using the tandem repetitive irritation test. Irritant cutaneous reactions were measured by noninvasive biophysical methods with transepidermal water loss as a parameter for permeability barrier function and skin colour reflectance together with visual scoring as parameters for inflammatory reactions. Results, Cold alone caused no significant skin reaction compared with untreated control. Exposure to SLS alone and SLS together with cold (independent of the applied temperature of 4 or 15 °C) twice daily induced a clear irritant reaction and barrier disturbance. Reactions did not differ whether SLS was applied before or after cold. Furthermore, ,tandem application' of cold and SLS diminished the barrier disruption and irritant reaction compared with SLS alone. Conclusions, We conclude that the application of cold may have a protective effect on the development of ICD, at least in our short-term model. [source] Simultaneous sodium lauryl sulphate testing improves the diagnostic validity of allergic patch tests.BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2005Results from a prospective multicentre study of the German Contact Dermatitis Research Group (Deutsche Kontaktallergie-Gruppe Summary Background, There is evidence that a higher skin susceptibility may induce nonspecific erythematous or weak positive reactions to contact allergens in patch testing. Objectives, To evaluate whether simultaneous application of sodium lauryl sulphate (SLS) along with diagnostic patch tests with contact allergens can provide information regarding skin irritability which may help to discriminate allergic from nonspecific irritant reactions to contact allergens. Methods, Between July 2001 and June 2003, this prospective study collected patch test data of 5971 patients from 19 centres in Germany and Austria in the Information Network of Departments of Dermatology (IVDK). In addition to contact allergens (standard series and eight known ,problematic' allergens with a low reaction index and a high positivity ratio: 1,3-diphenylguanidine, amerchol L-101, benzalkonium chloride, benzoyl peroxide, cocamidopropyl betaine, octyl gallate, phenyl mercuric acetate and propylene glycol), patches with SLS 0·5% and 0·25% aq. were applied. Reactions to the allergens and to SLS were analysed at the IVDK data centre. The association between an erythematous or positive reaction to a certain allergen and an irritant reaction to SLS was assessed with logistic regression analysis, at the same time controlling for the influence of age and sex. Results, Of the 29 allergens of the standard series, 23 and 21 gave a higher percentage of nonspecific erythematous reactions in patients with an irritant reaction to 0·25% and 0·5% SLS, respectively, in comparison with SLS-negative patients. All eight ,problematic' allergens gave an increased percentage of nonspecific erythematous reactions. Similarly, 22 and 21 allergens of the standard series gave a higher percentage of positive allergic reactions in patients with an irritant reaction to 0·25% and 0·5% SLS, respectively, and seven of the eight ,problematic' allergens gave a higher percentage of positive allergic rections (exception: octyl gallate). For most allergens, the markers of skin reaction (reaction index and positivity ratio) were worse in SLS-positive patients. Differences were more pronounced when testing with SLS 0·25% than with SLS 0·5%. Conclusions, Because there is a convincing association between skin irritability (evaluated by SLS test) and the degree of skin reaction to contact allergens, the SLS test may help in deciding whether a doubtful erythematous or weakly ,positive' skin reaction should be interpreted as allergic or irritant. [source] Artificial disruption of skin barrier prior to irritant patch testing does not improve test designBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2004K.L. Gebhard Summary Background, Irritant patch testing is often performed as a 24- or 48-h occlusive patch test with low concentrations of sodium lauryl sulphate (SLS). Objectives, The aim of this study was to investigate potential ways to shorten this test procedure and obtain precise test results. Patients and methods, Thirty-six healthy volunteers underwent irritant patch testing with different pretreatments (PT) of the test fields. Occlusive test chambers were applied on the upper back with SLS 0·5%, 1%, 2% and 5% in large Finn Chambers®. The patches were removed after 4 and 24 h, respectively, depending on the concentration used. Test fields were pretreated as follows: PT 0, field without any PT (control); PT 1, prick with lancet; PT 2, prick with test stamp; PT 3, scratch with lancet; PT 4, incision with standardized incision instrument (0·1,0·2 mm depth). Skin reactions were evaluated by transepidermal water loss (TEWL), skin erythema and skin hydration and as well by a visual score (VS) at 4, 24 and 72 h. Results, Our data show an obvious distinction between PT 0,2 and PT 3,4 at all measurement methods. The average TEWL values with PT 3,4 were higher than those with PT 0,2, especially on the 4-h course. This distinction may derive from the shape and size of the skin impairment achieved by PT 3,4, leading to a mechanical barrier disruption. However, SLS may infiltrate directly into deeper skin layers supported by capillarity. Consequently, no or little penetration through the epidermis and interaction with its structures occurs, which is responsible for irritant skin reactions. The SLS dose in the upper skin layers is therefore lower at these PTs. The lower remaining dose of SLS also explains this distinction, especially for the VS. Additionally, there are presumed reactions in deeper layers of the epidermis and dermis at PT 3,4. Conclusions, In summary, all data suggest a different reaction pattern from the classical irritant response. Therefore, application without any PT seems to be best suited for irritancy skin testing, especially for visual assessment. PTs prior to irritant patch testing have been shown to be unjustifiable. [source] | ||||||||||