Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-069X
    Keywords: Key words HPLC ; Skin barrier ; In vivo extraction ; Lipids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The inner stratum corneum is likely to represent the location of the intact skin barrier, unperturbed by degradation processes. In our studies of the physical skin barrier a new high-performance liquid chromatography (HPLC)-based method was developed for the quantitative analysis of lipids of the inner stratum corneum. All main lipid classes were separated and quantitated by HPLC/light scattering detection (LSD) and the free fatty acid fraction was further analysed by gas-liquid chromatography (GLC). Mass spectrometry (MS) was used for peak identification and flame ionization detection (FID) for quantitation. Special attention was paid to the free fatty acid fraction since unsaturated free fatty acids may exert a key function in the regulation of the skin barrier properties by shifting the physical equilibrium of the multilamellar lipid bilayer system towards a noncrystalline state. Our results indicated that the endogenous free fatty acid fraction of the stratum corneum barrier lipids in essence exclusively consisted of saturated long-chain free fatty acids. This fraction was characterized as a very stable population (low interindividual peak variation) dominated by saturated lignoceric acid (C24:0, 39 molar%) and hexacosanoic acid (C26:0, 23 molar%). In addition, trace amounts of very long-chain (C32-C36) saturated and monounsaturated free fatty acids were detected in human forearm inner stratum corneum. Our analysis method gives highly accurate and precise quantitative information on the relative composition of all major lipid species present in the skin barrier. Such data will eventually permit skin barrier model systems to be created which will allow a more detailed analysis of the physical nature of the human skin barrier.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/aims: A novel approach for reducing the undesired irritating properties of detergents on skin might be offered by betaine, which is a natural product derived from the sugar beet. The aim of the study was to explore the ability of betaine to reduce the irritating effects of two surfactants, sodium lauryl sulphate (SLS) and cocoamidopropylbetaine (CAPB). For evaluation of changes in skin reactions visual scoring, electrical impedance, transepidermal water loss and histology were used.Methods: Twenty-one healthy subjects were patch tested for 24 h with SLS and CAPB alone and together with betaine, betaine alone, and the two controls distilled water and an unoccluded test site on both volar forearms. Responses were evaluated by measuring electrical impedance and transepidermal water loss before exposure and 24 h after the removal of the test substances, and also by visual inspection and histology. The electrical impedance device enables measurements at 31 frequencies and relevant information was extracted from the spectra using four indices.Results: CAPB was found to be less irritating than SLS. The used detergents gave rise to distinctive impedance patterns also reflected by different types of histopathological skin responses. After the adding of betaine, the irritant reaction decreased for both detergents.Conclusions: Betaine is a promising ingredient to reduce the side effects of detergents and electrical impedance is a suitable tool both to quantify the degree of irritation as well as to differentiate between various types of reactions.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/aim: It is known that the properties of human skin vary locally. The purpose of this study was to investigate the properties of human volar forearms even further using advanced non-invasive techniques and numerical methods.Methods: The skin properties of human volar forearms were investigated using measurements of trans epidermal water loss and multifrequency electrical impedance. Eight sites on the forearms of 27 healthy volunteers were measured. The sites were oriented as squares, four sites on both left and right forearm, approximately 40–50 mm apart.Results: Analysis of variance showed significant differences for epidermal water loss (P 〈 0.01) and the skin impedance (P 〈 0.001) between the inner and outer sides of the arms. Additionally, parallel factor analysis of the full skin impedance spectra also showed that there are systematic differences between right and left arm (P 〈 0.01).Conclusion: It is crucial to design skin studies carefully in order to minimise the effects of the local skin properties of human skin.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/aims: Products containing detergents can damage the skin and give rise to irritant contact dermatitis. Therefore, attempts have been made to find less irritating detergents as well as substances decreasing undesired side-effects of detergents, and a novel approach is offered by betaine. The aim of the study has been to determine the irritating properties of some liquid soaps for personal hygiene and to map the effect of different concentrations of betaine using electrical impedance, trans-epidermal water loss and visual inspection.Methods: Twenty-eight healthy subjects were patch tested with different commercial soaps with and without betaine and sodium lauryl sulphate on both volar forearms for 24 h. A site with distilled water and an unoccluded area were used as references. Responses of the skin reactions were evaluated by visual inspection and by measuring trans-epidermal water loss and electrical impedance before application and 24 h after removal of the chambers.Results/conclusions: Significant skin reactions were found for all soaps tested but the soaps containing betaine were the least irritating. However, the skin irritation did not decrease with increasing concentrations of betaine in the tested range. On the whole the differences between the products were not large. The non-invasive methods used were more sensitive than visual assessment for evaluation of invisible or barely visible skin responses.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/aims: Purpose of this investigation was to assess benign pigmented cellular nevus (BEN), basal cell carcinoma (BCC), dermatofibroma (DER), dysplastic nevus (DYS), and seborrheic keratoses (SEB) using in vivo non- invasive electrical impedance technique.Methods: Electrical impedance was measured at 258 BEN, 34 BCC, 17 DER, 35 DYS, and 26 SEB lesions. Controls were measured at healthy skin close to the lesions. The impedance was measured between 1 kHz and 1 MHz at five depth settings. After the impedance measurements the lesions were histopathologically diagnosed. The impedance spectra were parameterized to four indices prior to the statistical analysis of the data.Results: There were significant differences between the lesions and their controls for BEN (P 〈 0.001), BCC (P 〈 0.001), DYS (P 〈 0.01), and SEB (P 〈 0.01).Conclusions: There are clear statistical differences between impedance of common lesions and control skin. With some further developments, the impedance technique can be useful as a diagnostic decision support tool for skin cancer assessment.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: During previous studies on the electrical impedance of the skin, we formulated a set of four physical indices that could be used to distinguish between the cutaneous effects produced by different chemical irritants. We now employ the electrical impedance technique to compare the properties of different anatomical areas of the skin, using the same set of indices.〈section xml:id="abs1-2"〉〈title type="main"〉Methods: Investigations were performed on 131 healthy volunteers, who were divided into four groups on the basis of age and sex. Readings of electrical impedance were taken from ten different regions over the body, and transepidermal water loss was measured for comparison.〈section xml:id="abs1-3"〉〈title type="main"〉Results: Baseline values of electrical impedance of the skin were shown to vary, depending on the site. Age was also found to exert a major influence, causing an increase in the indices related to magnitude (MIX, RIX, and IMIX) with increasing age, and a decrease in that related to phase (PIX), while sex had only a marginal effect.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions: As with other non-invasive techniques, baseline characteristics differ from place to place over the body surface, and age is another important determining factor.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: There is a need for objective and noninvasive methods to quantify and classify weak reactions in the skin. We have explored the capacity of the electrical impedance technique to evaluate mild irritant skin reactions and responses below the clinical threshold by using low concentrations of sodium lauryl sulphate.〈section xml:id="abs1-2"〉〈title type="main"〉Methods: Twenty-one healthy subjects were patch tested with 0.004, 0.02, 0.1 and 0.5% sodium lauryl sulphate on both volar forearms. An unoccluded area was used as a reference site. Values were recorded before application and 24 h after removal of the chambers. The magnitude and phase of electrical impedance were measured in the frequency range 1 kHz to 1 MHz at five depth settings. Four indices were devised from the impedance data, and the values obtained were statistically analysed.〈section xml:id="abs1-3"〉〈title type="main"〉Results: Between day 1 and day 3, statistically significant differences were found from the concentration of 0.02%, and the significance level increased from depth 1 to depth 5.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusion: Our results confirm that the electrical impedance method is a sensitive technique for detection of macroscopically negative responses induced by sodium lauryl sulphate, and that depth selection can be used to optimise the signal-to-noise ratio.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In our previous studies of the electrical impedance of the skin, we formulated a set of physical indices that could be used to distinguish between the cutaneous effects produced by different chemical irritants. We now describe an investigation of allergic contact reactions, using the same set of impedance indices for characterization.〈section xml:id="abs1-2"〉〈title type="main"〉Methods: Skin reactions were induced in the forearm of eight female patients who were allergic to nickel by exposure to nickel sulphate in petrolatum at various concentrations. The responses were evaluated by measurements of electrical impedance and transepidermal water loss, as well as by visual scoring and biopsy. Normal skin was used for controls.〈section xml:id="abs1-3"〉〈title type="main"〉Results: Different degrees of allergic contact reactions were produced, and the changes in value of the impedance indices were found to follow a particular pattern. This pattern diverged markedly from that obtained in controls, and the differences were statistically significant.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions: Our results suggest that, by the application of a technique based on electrical impedance, it will be possible to characterize allergic skin reactions.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/purpose: Bio-electrical impedance spectra of skin cancer and other lesions can be assessed using both regular non-invasive probes and a novel type of microinvasive electrode system with a surface furnished with tiny spikes that penetrate stratum corneum. The aim of the study was to compare the accuracy of detection for various types of skin cancer using impedance spectra measured with these two different electrode systems in an objective way without optimising the power of discrimination.Methods: Impedance spectra of 99 benign nevi, 28 basal cell carcinomas (BCC), and 13 malignant melanomas (MM) were measured using the two electrode systems. Classification of the lesions was made using Fisher's linear discriminant, and the sensitivities and specificities of the techniques were estimated using cross-validation.Results: The best separation between nevi and BCC was achieved using the regular non-invasive probe (96% sensitivity and 86% specificity), whereas the best separation between nevi and MM was achieved using the microinvasive electrodes (92% sensitivity and 80% specificity).Conclusions: Our results indicate that the choice of electrode system is application dependent.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Skin research and technology 10 (2004), S. 0 
    ISSN: 1600-0846
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/aims: In an earlier study, we have shown that the electrical impedance (IMP) is dependent on the lipid content of the stratum corneum as studied by lipid extraction. Therefore, we now employ the IMP technique to compare the properties of clinically normal atopic skin with that of non-atopic skin. We looked at the same time at concomitant alterations in transepidermal water loss (TEWL) and skin moisture results.Methods: Twenty-two healthy participants and 26 patients with atopic dermatitis were recruited. One test site on each volar forearm was used in the test procedure, of cyclohexane swabbing, skin stripping, and lipid extraction using a mixture of hexane:isopropanol. Responses were evaluated by measuring TEWL, skin moisture using electrical capacitance, and finally IMP spectroscopy in the frequency range 1 kHz to 1 MHz before the start of the study, after each step of the test procedure, and also during a 2 weeks recovery period.Results: Only the IMP results showed significant changes between baseline values of clinically normal atopic skin and healthy skin. Furthermore, IMP and TEWL showed significantly larger reactivity for the atopic group after the skin stripping procedure, and IMP after lipid extraction as well.Conclusion: Our results show that IMP is a useful method for detection of changes in the lipid content of the stratum corneum by discriminating healthy looking atopic skin from healthy control skin, and to detect changes in reactivity between the two groups.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...