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Lipid analysis and transepidermal water loss in snakes / Nicole Widler in IFSCC MAGAZINE, Vol. 5, N° 1 (01-02-03/2002)
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Titre : Lipid analysis and transepidermal water loss in snakes Type de document : texte imprimé Auteurs : Nicole Widler, Auteur ; Andreas Sigrist, Auteur ; Frank M. Gafner, Auteur Année de publication : 2002 Article en page(s) : p. 24-29 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Analysis Aridity 'Skin lipids' Reptiles Snakes 'Transepidermal water loss' Index. décimale : 668.5 Parfums et cosmétiques Résumé : The lipids of 101 snake sheddings from 32 different species kept at Pentapharm's serpentarium were extracted and analized by HPLC/LSD (light scattering detection) and TLC. The snake shadding extracts were compared with those of human stratum corneum. As revealed by HPLC/LSD analysis, the lipids from the various snake species and from humans are qualitatively not very different. The greatest differences could be observed quantitatively in the neutral lipids such as cholesterol. Main components are cholesterol, fatty acids, triglycerides, glycoceramides and phospholipids. The TLC analysis indicated that the extracts differ above all in the composition of neutral lipids, in contrast to polar lipids that do not show many differences. The transepidermal water loss (TEWL) of 19 different snake species was measured for the first time, according to our knowledge, directly in-vivo using a Tewameter. The results show that undisturbed snakes have a considerably lower TEWL than a stressed common lancehead ( Bothrops atrox). The results of the lipid analysis as well as the direct in-vivo TEWL measurements did not allow confirmation of the thesis of an inverse correlation between the TEWL of a snake and the aridity of its habitat.
The HPLC/LSD analysis of human stratum corneum showed a very similar profile a the chromatograms of the snake sheddings. Our analysis did not allow for differentiation between the various classes of ceramides and other lipids that may account for the differences in percutaneous absorption that have been reported for snake and human skin. But on a group-classification basis, snake sheddings should be taken into account as a simple stratum corneum model considering the ease of appendageal penetration pathways have to be kept in mind. A similar esterase activity in snake sheddings and human skin was described previously.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10663
in IFSCC MAGAZINE > Vol. 5, N° 1 (01-02-03/2002) . - p. 24-29[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 004652 - Périodique Bibliothèque principale Documentaires Disponible Testing the Discriminative Capacity of Compartmental Modeling for the Analysis of the In-Vivo Epidermal Water Content Changes Following Topical Application under Occlusion / Pedro Contreiras Pinto in IFSCC MAGAZINE, Vol. 5, N° 2 (04-05-06/2002)
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Titre : Testing the Discriminative Capacity of Compartmental Modeling for the Analysis of the In-Vivo Epidermal Water Content Changes Following Topical Application under Occlusion Type de document : texte imprimé Auteurs : Pedro Contreiras Pinto, Auteur ; Luis Marcelo Pereira, Auteur ; Rui Minhos, Auteur ; Luis Monteiro Rodrigues, Auteur Année de publication : 2002 Article en page(s) : p. 87-92 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Skin hydration' 'efficacy testing' 'mthematical modeling' POST 'in-vivo measurement' evaporation 'dynamic water loss' TEWL Index. décimale : 668.5 Parfums et cosmétiques Résumé : Mathematical modeling of cutaneous variables is an attratictive strategy to meet the compex nature of in-vivo skin, especially in the presence of an external stimulus such as a topical product. Despite the oversimplification implied, meeting the conceptualization of the model with the representative (physiological) variables is still a major difficulty, often impairing the model validity.
Once achieved, however, its applicability will mostly depend on the demonstration of the accuracy and practicability of the model. In previous works, the authors developed a bi-compartmental model designed to dynamically describe the Trans-epidermal water loss(TEWL) curves obtained in-vivo from the Plastic Occlusion Stress Test (POST) methodology. Occlusion was performed in healthy human volunteers (n=10) occluded with either 10% glycerin in water solution or water alone. Desorption curves allowed to obtain kinetic parameters such as k(evap)(the water evaporation rate at skin surface), t1/2 evap(the evaporation half-life), and DWM (the dynamic water mass) allowing a detailed quantitative description of the hydration process. Results demonstrate that the proposed model is adequate to identify significant differences (p<0.05) between the curve profiles, revealing the different hydration mechanisms involved, and suggesting an interesting application potential for the substantiation and efficacy testing of cosmectics.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10649
in IFSCC MAGAZINE > Vol. 5, N° 2 (04-05-06/2002) . - p. 87-92[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 003874 - Périodique Bibliothèque principale Documentaires Disponible