Activation of T-cells from allergic patients and volunteers by p-phenylenediamine and Bandrowski's base.
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Allergic contact dermatitis is commonly associated with exposure to p-phenylenediamine. The aim of this study was to determine whether p-phenylenediamine (PPD) and/or Bandrowski's base (BB) stimulate T cells from allergic patients and volunteers, and to explore the relationship between T-cell immunogenicity and allergy. Lymphocytes from allergic patients proliferated with PPD and BB (n=8). Lymphocytes from 14/16 non-allergic individuals also proliferated following stimulation, but only with BB; cord blood lymphocytes failed to respond (n=6). Glutathione, which prevented BB formation, but not binding of PPD to cells and serum, did not prevent p-phenylenediamine-specific stimulation of patient lymphocytes. T-cell clones generated from allergic patients were stimulated separately with PPD and BB, while clones from volunteers proliferated with BB alone. Patient and volunteer clones secreted IL-4, IL-5, IL-13, TNF-alpha, MIP-1alpha, MIP-1beta, and RANTES. These data show that activation of T lymphocytes from allergic individuals alone with PPD represents an important discrimination between allergic and non-allergic groups. BB-specific T cells are found in both allergic patients and volunteers, but not in cord blood. Their presence seems to reflect an acquired immune response, which is not translated into an allergic reaction. (+info)
Microarray-based in vitro test system for the discrimination of contact allergens and irritants: identification of potential marker genes.
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Permanent waving does not change mercury concentration in the proximal segment of hair close to scalp.
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Mercury in hair is a generally accepted biomarker of methylmercury exposure, and permanent waving has been reported to affect the mercury concentration in hair. We conducted an experimental-field study to examine the changes in the mercury concentration in hair induced by treatments such as permanent waving, straightening and coloring. Hair samples were collected from 19 female subjects enrolled before and after hair treatment by a beautician during each visit to a beauty saloon. A total of 38 pair samples were cut in 1-cm segments from the proximal end up to 10 cm, and then as 2-cm segments up to the distal end thereafter. Each segment was analyzed for total mercury concentration by cold-vapor atomic absorption spectrometry. Permanent waving decreased mercury concentration for most of the segments except for the proximal two segments and the 8-9 cm segment from the proximal end. Nevertheless the average mercury concentration of 3-cm segments from the proximal end showed no significant decrease by permanent waving. Since females usually have hair longer than 3 cm, hair samples subjected to permanent waving may give lower mercury exposure estimates when the full-length hair strands are analyzed. However, analyzing the proximal 3-cm segment of hair samples does not give lower mercury exposure estimates. Assuming that hair samples are collected from puerperal women around the time of delivery, the 3-cm segments represent fetal exposure to methylmercury during the third trimester when fetuses are most vulnerable to methylmercury exposure. Therefore, mercury concentrations in the proximal segment of maternal hair collected in the right time can be a good biomarker of fetal methylmercury exposure. (+info)
Personal use of hair dye and the risk of certain subtypes of non-Hodgkin lymphoma.
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An in vitro assay to screen for the sensitizing potential of xenobiotics.
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We are developing a new, animal-free assay for determination of the sensitizing potential of a substance. The design of this assay is based on current immunological knowledge of the pathogenesis of allergic contact dermatitis. It integrates human dendritic cells and keratinocytes, which are both known to be critically involved in vivo. The read-out system uses molecular responses typically occurring after an encounter of the skin with contact allergens. The assay provides concentration-response information, by which the relative ability of a chemical to induce sensitization can be predicted. Additionally, the assay defines the border-concentration of general toxicity of a substance. Weak allergens and even prohaptens are detectable. We have called the assay LCSA, loose-fit coculture-based sensitization assay. (+info)
Use of hair colouring products and risk of multiple myeloma among US women.
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