Biomedical subjects

T Oppel

Publications and source records attributed to T Oppel.

6 recordsLinked to original sources

PubMed2006

[The most frequent allergens in allergic contact dermatitis].

BACKGROUND AND OBJECTIVE: The prevalence of allergic contact dermatitis is high. Patch testing is the standard procedure to detect contact sensitivity. More than 3000 allergens are known, today. On the basis of the data of this study the top allergens are presented. PATIENTS AND METHODS: The retrospective analysis is based on the patch test results collected by the Information Network of Departments of Dermatology in 2004. Data of 9948 patients (6175 female und 3773 male) referred for the evaluation of suspected contact allergy were analysed to determine the frequency of sensitization to the 10 most common contact allergens. RESULTS: The top ten allergens were nickel sulphate (frequency of sensitization standardized for sex and age 17.2 %), fragrance mix (7.2 %), balsam of Peru (6.7 %), cobalt chloride (6.5 %), potassium dichromate (5.3 %), colophony (4.6 %), lanolin alcohol (4.3 %), p-phenylenediamine (4.2 %), ammoniated mercury (3.5 %) und methyldibromoglutaronitrile/phenoxyethanol (3.4 %) in 2004. CONCLUSIONS: Even after healing of the skin lesions of allergic contact dermatitis, it must be considered that sensitization persists indefinitely. Therefore, patients have to be informed exactly about their relevant contact allergens to ensure complete avoidance. To do so, physicians need a detailed knowledge of the most common contact allergens which are discussed in this paper.

Adult↗

PubMed2000

Phenotyping of epidermal dendritic cells allows the differentiation between extrinsic and intrinsic forms of atopic dermatitis.

UNLABELLED: Atopic dermatitis (AD) is a clinically characteristic, chronic inflammatory skin disease of unknown origin. IgE-mediated uptake and antigen focusing of environmental allergens by dendritic cells (DCs) is assumed to be a central immunopathogenetic event. A so-called intrinsic type of AD (IAD) has been delineated from the more common extrinsic AD (EAD) by normal serum IgE levels, negative RAST tests and negative immediate-type skin reactions towards environmental allergens. The recently characterized human autoantigen Hom S 1 has been proposed to play a part in the pathogenesis of IAD. OBJECTIVES: To compare clinical and laboratory data between patients with IAD and EAD, and to investigate potential differences in the inflammatory micromilieu of the epidermal compartment in IAD and EAD lesions. METHODS: Epidermal DC phenotyping, a recently validated technique based on the three-colour flow cytometric analysis of Langerhans cells and the so-called inflammatory dendritic epidermal cells from epidermal single-cell suspensions, was performed on samples from 69 patients with AD (seven with IAD and 62 with EAD) and 94 controls. RESULTS: Patients with EAD tended to have an earlier onset of disease but similar disease duration and family history of atopic diseases. Quantitative analysis of CD36 expression on DCs as a marker of inflammation, as well as the percentage of inflammatory dendritic epidermal cells in the CD1a+ epidermal DC pool, indicated a comparable disease activity in IAD and EAD. EAD was characterized by a significantly higher FcepsilonRI expression on the CD1a+ epidermal DCs than IAD. Using the FcepsilonRI/FcgammaRII expression ratio as a disease marker for AD, values for IAD fell below the diagnostic cut-off level of 1.5 for this ratio. CONCLUSIONS: While IAD is clinically similar to EAD, the inflammatory microenvironment in this condition seems different from classical EAD and can be distinguished by phenotyping of epidermal DCs.

Adolescent↗

PubMed2000

Atopic dermatitis: pathogenetic mechanisms.

Atopic dermatitis (AD) is a chronic inflammatory skin disease with increasing incidence and socio-economical relevance. The diagnosis is made on clinical grounds and different diagnostic criteria sets have been established. The majority of all AD cases is associated with a sensitization to environmental allergens and increased serum IgE (so-called extrinsic AD), but about 10--30% of all cases suffer from the so-called intrinsic AD, which obviously lacks any link to the classical atopic diathesis. The genetic background of AD has been investigated by target gene approach by different groups with mostly contradictory results for each of the genes under study. An imbalance in the spectrum of Th1/Th2 responses, a disturbed prostaglandin metabolism, intrinsic defects in keratinocyte function, delayed eosinophil apoptosis, IgE-mediated facilitated antigen presentation by epidermal dendritic cells, a two phase model of the inflammatory response and staphylococcal superantigen effects are among the currently studied pathogenetical aspects of extrinsic AD, which are reviewed in this paper.

Dermatitis, Atopic↗

PubMed2000

NF-kappaB and AP-1 are responsible for inducibility of the IL-6 promoter by ionizing radiation in HeLa cells.

PURPOSE: To investigate the mechanisms leading to initiation by ionizing radiation of IL-6 transcription in HeLa cells. MATERIALS AND METHODS: HeLa cells were irradiated with X-rays at a dose rate of approximately 1 Gy/min or treated with TPA (100 ng/ml). Transient transfection analysis with truncated IL-6 promoter CAT constructs was used to identify the radiation-sensitive region within the IL-6 promoter/enhancer. RESULTS: For basal expression of the IL-6 gene in unirradiated control cells the presence of the binding site for the nuclear factor kappa B (NF-kappaB) and the multiple response elements (MRE) were necessary. After deletion of either the activator protein (AP)-1 or the MRE site, radiation-induced IL-6 promoter CAT activity was significantly reduced, whereas after deletion of the NF-kappaB site it was completely abolished. Maximal radiation-induced IL-6 promoter CAT activity was observed when the AP-1, NF-kappaB and MRE motifs were present. In electrophoretic mobility shift analyses (EMSA), X-ray-inducible activity was found for NF-kappaB and AP-1 at the MRE constitutive, but no inducible activities were detectable. The nuclear factor IL-6 (NF-IL6) element showed no specific radiation-responsive activity. CONCLUSIONS: These results demonstrate that NF-kappaB plays a major role in X-ray-inducible IL-6 expression in HeLa cells. The fact that IL-6 promoter activity was dramatically enhanced in the presence of the MRE and distal AP-1 binding motif is indicative of a cooperative mode of transcriptional activation involving all three transcription factor systems. These data provide new insights into the prodromal events of radiation-induced inflammation of epithelial cells and putatively the cutaneous radiation syndrome.

Binding Sites↗

PubMed1997

Induction of interleukin 6 by ionizing radiation in a human epithelial cell line: control by corticosteroids.

The cutaneous radiation syndrome after therapeutic or accidental exposure of human skin to ionizing radiation (IR) is accompanied by inflammatory processes which are controlled partly by proinflammatory cytokines. Besides tumour necrosis factor (TNF)-alpha and interleukin (IL)1, the pluripotent cytokine IL-6 belongs to the key mediators of inflammation. So far, there are no reports about the regulation of IL-6 by IR in epidermal cells. As an in vitro model to study the effects of IR on IL-6 gene expression, we treated the human epithelial HeLa cell line with different single X-ray doses between 1 and 20 Gy. Twenty-four hours after irradiation the IL-6 secretion was dose-dependently enhanced as measured by ELISA. At the transcriptional level, a slight increase of IL-6 transcripts was already detectable 1 h after irradiation, with maximum levels at 2 h, and a decline to baseline levels between 8 and 24 h. Addition of the transcriptional inhibitor actinomycin D inhibited the inducibility of IL-6 mRNA by TPA and IR. As the IL-6 promoter contains multiple binding sites for activated glucocorticoid receptors within the 5' regulatory region, the potential modulation of IL-6 expression by the corticosteroids hydrocortisone, dexamethasone and mometasone furoate was included in our study to modify the radiation-induced stress response. All corticosteroids applied could efficiently downregulate TPA- or radiation-induced IL-6 expression on both gene expression and protein levels. Mometasone furoate, followed by dexamethasone, was found to be most effective at low concentrations (1 nM), whereas hydrocortisone had to be applied at about 100-fold higher concentrations to achieve comparable inhibition. This experimental model is aimed at understanding the molecular circuits following IR, and thus to provide a basis for the treatment of radiation effects in skin.

Adrenal Cortex Hormones↗

PubMedDate not supplied

Actinic keratosis: the key event in the evolution from photoaged skin to squamous cell carcinoma. Therapy based on pathogenetic and clinical aspects.

Skin aging is the result of intrinsic and extrinsic factors. Extrinsic aging, also called photoaging, is mainly caused by ultraviolet radiation from the sun and leads to a state which has been termed dermatoheliosis. The aim of this article is to provide an overview of photoaged skin addressing actinic keratoses (AKs) in particular. This review will describe the clinical features of photoaged skin and briefly summarize the underlying histological, photobiochemical and molecular mechanisms responsible for photoaging. The concept of the disease continuum from AK to squamous cell carcinoma will also be presented. A special focus will be on established and new therapeutic approaches to undo photoinduced skin damage.

Carcinoma, Squamous Cell↗