3 résultat(s) recherche sur le tag 'in-vitro''

The reproducibility of an in-vitro determination of the UVA INDEX describing the relative UVA protection of sun care products / DGK in IFSCC MAGAZINE, Vol. 5, N° 3 (07-08-09/2002)

[article]  inIFSCC MAGAZINE > Vol. 5, N° 3 (07-08-09/2002) . - p. 161-166 Titre : The reproducibility of an in-vitro determination of the UVA INDEX describing the relative UVA protection of sun care products Type de document : texte imprimé Auteurs : DGK, Auteur ; Task Force "Sun Protection", Auteur Année de publication : 2002 Article en page(s) : p. 161-166 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Produits antisolaires Tags : 'UVA  INDEX'  protection'  'Méthode  de  test  In-vitro'  'Protection  solaire'  Reproductibilité Index. décimale : 668.5 Parfums et cosmétiques Résumé : Due to overexposure to UVA and not only to UVB light significant alterations in damage to human skin were observed. Accordingly, the protection against UVA is a major additional requirement for sunscreens beside the effective prevention of sunburn. Despite the intensive debate on the appropriate measurement and labeling, up to now, no proposal was officially accepted in Europe and US. The recently published determination of the in-vitro PPD protection factor [1] was discerned as a candidate for future, harmonized UVA protection measurement? The method combines the merits of in-vitro as well as of in-vivo determinations. The aim of the present study was to investigate the inter-institutional reproducibility of the new UVA parameter and to determine how to express the UVA protection. Concerning the latter aspect, particular emphasize should be given to the importance of the SPF by describing the UVA protection in relation to the UVB protection efficacy. Seven laboratories participated in the Round Robin study and five marketed sunscreen formulations were tested. The sunscreens were selected to represent the major types of sun protection products. The application amount was fixed at 0.75mg/cm2 for all samples and for all institutes after ensuring in a pretest that the absorbance does not exceed the value of 2.0, because otherwise saturation phenomena could occur. Regarding the calculation of the in-vitro PPD protection factors, a high reproducibility was found. The average standard deviation for all five products was less than 15%. The good correlation between in-vitro and in-vivo PPD factors confirms the relevance of this methods. The UVA INDEX was defined as the relation between the in-vitro PPD factor and the labeled in-vivo SPF. Based on the simple transmission measurement and a calculation that takes into account the in-vivo effectiveness as references, it provides a rapid and valid procedure to evaluate and to differentiate the UVA protection of sunscreens. According to these findings, the UVA INDEX is seen as a potential candidate for UVA determinations. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10639 [article]

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Differential toxicity on monocytes and monocyte-derived dendritic cells : a new tool to differentiate allergens from irritants ? / Laetitia Furio in IFSCC MAGAZINE, Vol. 10, N° 1 (01-02/2007)

[article]  inIFSCC MAGAZINE > Vol. 10, N° 1 (01-02/2007) . - p. 27-33 Titre : Differential toxicity on monocytes and monocyte-derived dendritic cells : a new tool to differentiate allergens from irritants ? Type de document : texte imprimé Auteurs : Laetitia Furio, Auteur ; J. Guesnet, Auteur ; Blandine Ducarre, Auteur ; A. Guezennec, Auteur ; Daniel Schmitt, Auteur ; josette Peguet-Navarro, Auteur Année de publication : 2007 Article en page(s) : p. 27-33 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Hypersensibilité  cutanée'  'Méthode  alternative  in-vitro'  'Cellules  dendritiques'  Monocytes  Apoptose Index. décimale : 668.5 Parfums et cosmétiques Résumé : Phenotypic activation of monocyte-derived dendritic cells has been proposed as an in vitro alternative assay to discriminate potential sensitizers from irritants, but the sensitivity of the assay remains controversial. In this study, we first determined the dynamic range of expression of activation/maturation markers on human monocyte-derived dendritic cells cultured in the presence or absence of transforming growth factor ß (TGFβ)? On day three of culture, most monocytes had already differentiated into dendritic cells that expressed low levels of costimulatory molecules especially in the presence TGFβ-treatment of 3-day-old TGFβ-treated monocyte-derived dendritic cells with several chemicals at sub-toxic concentrations induced significant phenotypic changes for all the strong and mild sensitizers tested, whereas the irritant sodium lauryl sulfate had no effect. However, a very large variability was observed among the experiments. Most interestingly, we could show here for the first time that at concentrations sub-toxic for monocyte-derived dendritic cells all the allergens tested induced monocyte apoptosis within 2 days of culture. In contrast, sodium lauryl sulfate displayed similar toxicity on monocytes and monocyte-derived dendritic cells and these results were confirmed with other irritants such as benzoic acid or methylsalicylate. Although testing of far more chemicals is required, these results indicate that differential toxicity of chemicals to monocytes and monocyte-derived dendritic cells could be a rapid, simple and valuable tool to differentiate sensitizers from irritants. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10425 [article]

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Use of dendritic cells for the identification of skin allergens / Nicola Gilmour in IFSCC MAGAZINE, Vol. 6, N° 4 (10-11-12/2003)

[article]  inIFSCC MAGAZINE > Vol. 6, N° 4 (10-11-12/2003) . - p. 287-293 Titre : Use of dendritic cells for the identification of skin allergens Type de document : texte imprimé Auteurs : Nicola Gilmour, Auteur ; D. A. Basketter, Auteur Année de publication : 2003 Article en page(s) : p. 287-293 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Contact  allergène  'Cellules  dendritiques'  'Techniques  in-vitro'  de  Langerhans'  'Sensibilisation  alternatives'  peau' Index. décimale : 668.5 Parfums et cosmétiques Résumé : There are several factors that govern the induction of allergic contact dermatitis, including skin penetration, metabolism/protein reactivity, antigen uptake and activation of Langerhans cells/dendritic cells and their migration to the lymph node to stimulate T-cells and initiate an immunological response. Dendritic cells thus represent a key cell type for the development of in-vitro cell based alternatives for the detection of contact allergens. Dendritic cells cultures exposed to the strong contact allergen 2,4-dinitrochlorobenzene(DNCB) have shown up-regulation of certain markers,although with variability and not always with evidence of specificity. We aimed to derive a purified dendritic cell population (CD11c+ cells), a cell type more relevant for the identification of skin allergens. Pure populations of dendritic cells were isolated from human peripheral blood using magnetic bead separation. The cells were cultured for 5 days in a combination of granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-4(IL-4) and transforming growth factor-beta ( TGF-beta), to generate 'Langerhans cell-life'cells. This approach produced a population that was 95% CD1a positive as determined by flow cytometry. The cells expressed human leukocyte antigen (HLA)-DR but not cluster of differentiation (CD)-86 or CD83 antigens, demonstrated endocytic ability ( fluorescein isothiocyanate-dextran uptake), were weak stimulators of the mixed lymphocyte reaction and thus could be regarded as an 'immature' Langerhans cell phenotype. Exposure of these cells to sub-toxic doses of 2,4-dinitrochlorobenzene (as determined by the XTT assay) resulted in elevated expression of HLA-DR (2 to 7-fold increase in mean fluorescence intensity [MFI]) and CD86 (15 to 20-fold increas in MFI) compared to control cells. Concurrent treatment with sub toxic doses of the irritant sodium lauryl sulphate or 0.1% dimethylsulfoxide (vehicle control) did not induce up-regulation of HLA-DR or CD86. Culture of blood derived CD11c+ dendritic cells thus may provide a population of Langerhans-like cells for the in-vitro evaluation of potential skin sensitizers. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10547 [article]

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