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  • 1
    ISSN: 1432-069X
    Keywords: Clotrimazole ; Cytochrome P-450 isozymes ; Neonatal rats ; Skin effects ; Mono-oxygenase activities ; Liver effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clotrimazole, an N-substituted imidazole, is a widely used topical agent for the treatment of superficial fungal infections. In this study, the effect of application of clotrimazole to the skin of neonatal rats on the induction response of the cytochrome P-450-dependent monooxygenase system in epidermis and liver has been examined. A single topical application of clotrimazole (10 mg/100 g) to rats resulted in a 53% increase in hepatic cytochrome P-450 content. Clotrimazole treatment also resulted in significant induction of epidermal 7-ethoxycoumarin-O-deethylase activity. Hepatic p-nitrophenol hydroxylase, an enzyme, catalyzed principally by the ethanol inducible cytochrome P-450 isozyme, was also significantly induced (58%) by topically applied clotrimazole. This enzyme activity was undetectable in epidermal microsomes. Further characterization of the cytochrome P-450 isozymes induced in liver by clotrimazole treatment was based on monoclonal antibodies (MAbs) raised against purified rat liver cytochrome P-450 isozymes induced by phenobarbital (MAb 2-66-3) and ethanol (MAb 1-98-1). Hepatic microsomes prepared from clotrimazole-treated rats showed significant immunoreactivity on Western blot with both the MAbs whereas no reactivity occurred in epidermal microsomes. Our data indicate that topical application of clotrimazole to rats results in the induction of selected cytochrome P-450 isozyme(s) in liver and epidermis which may have implications for the therapeutic use of this compound.
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  • 2
    ISSN: 1432-069X
    Keywords: Arylhydrocarbon-hydroxylase (AHH) ; Epidermal cells ; Cell proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cytochrome P-450-dependent arylhydrocarbon-hydroxylase (AHH) activity and inducibility by benzanthracene (BA) was measured in cultured guinea pig and human epidermal cells. Basal AHH-activity (AHHb) in guinea pig epidermal cells was much higher than in human epidermal cells. AHHb in guinea pig epidermal cells was directly related to the labeling index and decreased to the original level between the 5th and 7th day of cell culturing. On the other hand, the induction-ratio of AHH reached its maximum level when the number of cells began to rise (proliferation phase) and remained high at day 7 of the cell culture. These results suggest a cell growth dependent activity and inducibility of carcinogen-metabolizing enzymes, such as AHH, in isolated epidermal cells.
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  • 3
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Basophil activation is associated with the expression of CD63. Because allergens can induce basophil activation by cross-linking specific IgE, increased CD63 expression has been proposed as a novel in vitro test for immediate type allergy.Objective We compared the CD63-based basophil activation test (BAT) in the diagnosis of allergy to carrot, celery and hazelnut with skin prick tests (SPT) and measurement of allergen-specific IgE.Methods Twenty-nine patients with a history of an oral allergy syndrome induced by carrot, celery or hazelnut (n = 20 for each allergen) and 20 controls were studied. SPT were performed with standardized and native carrot, celery and hazelnut extracts. Allergen-specific IgE was determined by the CAP FEIA method and basophil activation was determined by flow cytometry upon double staining with anti-IgE/anti-CD63 mAb.Results SPT with native carrot, celery and hazelnut showed sensitivities of 100%, 100% and 90%, and specificities of 80%, 80% and 90%. SPT with commercial extracts of the same allergens gave sensitivities of 85%, 80% and 85%, and specificities of 80%, 80% and 90%. Sensitivity of allergen-specific IgE and the BAT for carrot, celery and hazelnut was 80% vs. 85%, 70% vs. 85%, and 80% vs. 90%, with corresponding specificities of 80% vs. 85%, 80% vs. 80%, and 95% vs. 90%. The cut-off for a positive BAT was 10% CD63+ basophils. Moreover, there was a positive correlation between IgE reactivity and the number of CD63+ basophils for all food allergens (carrot: r = 0.69, celery: r = 0.67, hazelnut: r = 0.66).Conclusions Quantification of basophil activation by CD63 expression is a valuable new in vitro method for diagnosis of immediate type food sensitization. Although double-blind placebo-controlled food challenges remain the gold standard, the CD63-based BAT may supplement routine diagnostic tests such as SPT or allergen-specific IgE in the future.
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  • 4
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background:  As in vitro diagnosis of wasp venom sensitization by specific serum IgE has a sensitivity of only 60–80%, additional in vitro tests are desirable. Basophil activation is associated with the expression of CD63 and its measurement has been proposed as a novel in vitro test for immediate-type allergy. Furthermore, to date, no in vitro test exists to monitor successful specific immunotherapy (SIT) with wasp venom. Therefore, the potentially harmful sting challenge is still recommended.Objective:  We compared the CD63-based basophil activation test (BAT) in the diagnosis of wasp venom allergy with skin tests and measurement of specific IgE. Furthermore, we investigated whether BAT can predict the outcome of the sting challenge in patients on SIT.Methods:  Fifty patients with a systemic reaction caused by a wasp sting and 20 controls were studied. Intracutaneous tests were performed with wasp and bee venom in the suspected allergics. Specific IgE was determined by the CAP-FEIA method and basophil activation by flow cytometry upon double staining with anti-IgE/anti-CD63 mAb. Twenty-five patients were sting challenged 6 months after starting SIT and the BAT was repeated before challenge.Results:  Sensitivity of the intracutaneous tests, specific IgE and BAT was 100, 76, and 92%, respectively. Specificity of specific IgE and the BAT was 85 and 80%, respectively. The cut-off for a positive BAT was 15% CD63+ basophils. There was a positive correlation between IgE reactivity to wasp venom and the number of CD63+ basophils (r = 0.65). Although no patient had a systemic reaction upon sting challenge, in most subjects basophil activation did not decrease when compared with the BAT before SIT.Conclusions:  Quantitation of basophil activation by CD63 expression is a valuable new in vitro method for diagnosis of allergy to hymenopteran venoms. The CD63-based BAT is a helpful tool for the complementation of routine diagnostic tests such as specific IgE as it increases sensitivity of in vitro detection of sensitization. However, this in vitro method does not offer an alternative to the sting challenge in monitoring successful SIT.
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  • 5
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: We report on two cases of allergic contact dermatitis to chloramphenicol and azidamphenicol respectively, with in vivo and in vitro lymphocyte reactivity to both compounds. The molecular features determining lymphocyte reactivity were explored because chloramphenicol, azidamphenicol, and thiamphenicol exhibit almost identical chemical structures. Methods: With chloramphenicol, azidamphenicol, and the chemically related thiamphenicol, we performed patch tests and lymphocyte transformation tests with both patients. Furthermore, the interleukin-5 and interferon-γ concentrations in the cultures of peripheral blood mononuclear cells of one patient were determined. Results: Patch tests showed delayed hypersensitivity reactions to chloramphenicol and azidamphenicol, but not to thiamphenicol. These results were confirmed by lymphocyte transformation tests with peripheral blood mononuclear cells of the patients, showing a proliferative T-cell response to azidamphenicol and chloramphenicol. Moreover, lymphocytes from one patient secreted large amounts of interleukin-5, but not of interferon-γ upon coculture with azidamphenicol. Conclusions: Since lymphocyte reactivity was observed to chloramphenicol and azidamphenicol, but not to thiamphenicol, the epitope(s) recognized by the allergen-reactive T cells may be formed by the nitro-group of the benzene ring shared by chloramphenicol and azidamphenicol.
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  • 6
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Allergy 56 (2001), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background In vitro detection of drug sensitization is still limited. The lymphocyte transformation test, which determines drug-specific proliferation, is the only in vitro test for detecting drug sensitization at the cellular level irrespective of the reaction's clinical phenotype. Accumulation of eosinophils following IL-5 secretion from drug-specific stimulated T cells is a characteristic histological feature of drug-induced skin eruptions.Objective We determined whether in vitro drug-specific activation of ex vivo peripheral blood mononuclear cells from 10 patients with drug-induced maculopapular exanthems and three patients with severe skin reactions results in secretion of IL-5, IL-10 or IFN-γ and assessed the sensitivity and specificity of drug-specific IL-5 secretion as a test system compared with the lymphocyte transformation test and patch tests. Furthermore, the subsets of CD4+ and CD8+ T cells involved in drug-specific proliferation, IL-5 secretion and mRNA expression were examined in three patients.Methods Drug-specific proliferation of peripheral blood mononuclear cells in the lymphocyte transformation test was investigated by 3H-thymidine uptake, and culture supernatants taken after 5 days were analysed for IL-5, IL-10 and IFN-γ concentrations by ELISA technique. IL-5 mRNA expression was determined by RT-PCR.Results Drug-specific activation of peripheral blood mononuclear cells consistently resulted in IL-5 and to a lesser extent in IL-10 and IFN-γ secretion. The sensitivities of the patch test, lymphocyte transformation test and assessment of drug-specific IL-5 secretion for the detection of drug sensitization were 55%, 75% and 92%, respectively.Conclusion These data suggest a role for the determination of drug-specific IL-5 secretion by ex vivo peripheral blood mononuclear cells for the in vitro detection of drug-sensitization in drug-induced maculopapular exanthems.
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  • 8
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Contact dermatitis 44 (2001), S. 0 
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
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  • 10
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We investigated whether patients with contact allergy differed from non-contact-allergic, non-atopic controls with regard to genotype and phenotype of the polymorphic enzyme N-acetyltransferase 2 (NAT2). 55 contact-allergic patients recruited from the Information Network of Departments of Dermatology (IVDK) were compared to 85 controls from among local health care personnel. NAT2 activity was calculated from HPLC analysis of the ratio of the caffeine metabolites 5-acetylamino-6-formylamino-3-methyluracil (AFMU) and 1-methylxanthine (1MX) in the urine. NAT2 genotype was determined by polymerase chain reaction (PCR). A statistically significantly increased proportion of rapid acetylators was found in contact-allergic patients. This may have 2 possible implications: acetylation may enhance contact sensitization; or NAT2 status may be a genetic marker for contact sensitizability.
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