Search Results - (Author, Cooperation:D. Schmitt)

2015-06-02

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Age Factors ; Alleles ; Chromosome Mapping ; *DNA Methylation ; *Epigenesis, Genetic ; Female ; Gene Expression Profiling ; Gene Expression Regulation ; Genetic Variation ; Humans ; Male ; Organ Specificity

2015-11-26

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

2011-12-24

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2013-10-22

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Cell Line ; Chromatin/chemistry/genetics/*metabolism ; *Chromosome Mapping ; Enhancer Elements, Genetic/physiology ; Gene Expression Regulation ; *Genome, Human ; Humans ; Imaging, Three-Dimensional ; Promoter Regions, Genetic/physiology ; Protein Binding ; Signal Transduction ; Tumor Necrosis Factor-alpha/metabolism

1089-7550

AIP Digital Archive

Physics

Measurements of the parallel M(parallel) and perpendicular M⊥ components of the magnetization to the applied magnetic field HA have been carried out for all directions in the (010) plane on single crystals of hexagonal NdNi5, TbNi5, and HoNi5. These measurements were performed using a steady magnetic field of 15 kOe, in the ferromagnetic phase down to 4 K. These kinds of experiments allow a detailed description of the magnetocrystalline anisotropy to be given. The polar dependencies of the M(parallel) and M⊥ isotherms have been explained using a microscopic single-ion crystal electric field (CEF) and a molecular-field approximation to describe the exchange interaction.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background  Normal and dysregulated wound healing involves fibroblast activation and angiogenesis, in which polypeptide factors such as transforming growth factor (TGF)-β, vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) play an important part. Ultraviolet (UV) A1 (365 nm) has recently received attention as a possible treatment for some dermal fibrotic disorders. Objectives The aim of this study was to evaluate the effects of TGF-β1 and UVA1 radiation, as well as that of cobalt chloride, reported to mimic hypoxia both in vivo and in vitro, on the expression of VEGF and ET-1 by cultured human dermal fibroblasts. Methods Levels of VEGF and ET-1 were measured by enzyme-linked immunosorbent assay and expression of neutral endopeptidase (NEP, CD10), known to degrade ET-1, was quantified by flow cytometric analysis after cell trypsinization. Results Our results showed that the cells released minor amounts of VEGF and ET-1. Both TGF-β1 and UVA1 strongly increased VEGF secretion in a dose- and time-dependent manner, without significantly affecting ET-1 release. Irradiation of TGF-β1-stimulated fibroblasts resulted in a synergistic effect on increasing levels of VEGF but not ET-1 after 48 h. Cobalt chloride stimulated the secretion of VEGF by fibroblasts; the effects of TGF-β1 and cobalt were additive. However, no significant effect of cobalt chloride on ET-1 secretion was observed, suggesting that ET-1 production in fibroblasts is not oxygen-sensitive. The expression of NEP was not modified by TGF-β1 or UVA1 radiation. Addition of a neutralizing anti-CD10 antibody to fibroblast cultures downregulated CD10 expression at the cell surface without changing ET-1 levels in cell supernatants after 24 or 48 h. This suggests that membrane-bound NEP has minimal or no activity against secreted ET-1. Conclusions Taken together, these results underline the major role played by TGF-β1 in increasing VEGF secretion by fibroblasts. This, as well as the documented effect of UVA1 on increasing VEGF production, may have implications for wound healing in vivo.

Electronic Resource

1365-2230

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

In allergic and irritant contact dermatitis, keratinocytes are major target cells that can be activated to take part in local reactions by secreting soluble mediators. Among the growth factors produced by keratinocytes, vascular endothelial growth factor (VEGF) is a powerful inducer of permeability of endothelial cells, and is involved in inflammation. We determined whether different contact allergens, dinitrosulphobenzene (DNSB), para-phenylenediamine (pPD) and the metals nickel and chromium, as distinct from cobalt, which has been shown to mimic the effects of hypoxia, can modify the basal level of VEGF in normal human keratinocytes when tested at various, non-toxic concentrations. The effects of an irritant, sodium lauryl sulphate (SLS), and of hydrocortisone were also tested. Our results showed an intense dose-dependent upregulation of VEGF release by keratinocytes after treatments by metals, pPD and SLS. DNSB induced only a moderate increase of VEGF. Hydrocortisone reduced the basal level as well as the nickel-induced upregulation of VEGF. These findings suggest that contact allergens and irritants probably upregulate VEGF in keratinocytes by different mechanisms and may contribute directly to the microvascular hyperpermeability which characterizes both contact and irritant dermatitis.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1600-0560

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The purpose of the present study was lo examine the phenotype of the cutaneous immunocompetent cells in lichen planus and chronic graft versus host (GVH) reaction infiltrates, by the use of monoclonal antibodies directed against T cell populations and Langerhans cells.Our results in lichen planus suggest an immunological reaction similar to the delayed hypersensitivity reaction, including all the immunocompetent cell sub-populations, with a first stage of antigenic information by Langerhans cells (OKT6 +, BL6 +, HLA-DR+) and helper cells, and a second stage mediated by suppressor/cytotoxic cells.The results from the study of GVH reaction also suggest an effect mediated by suppressor/cytotoxic cells (OKT3+, OKT4−, OK.T8+, HLA-DR+).Our results favour the existence of a lymphocytotoxic process in lichen planus and chronic GVH reaction.

Electronic Resource

1744-313X

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Langerhans cells (LC) play an important role in the skin immune system. They are bone marrow-derived and function as the only accessory and antigen-presenting cells in the skin. Several techniques for enriching these cells have been devised, and four, including density gradient centrifugation, use of cell sorter, panning and immunomagnetic separation, are discussed. It is concluded that the most satisfactory method for isolation of LC is based on density gradient centrifugation and the most satisfactory for depletion of epidermal cell preparations for LC is based on the immunomagnetic principle.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The densities of feline epidermal dendritic cells expressing CD18. MHC class II and CD1a antigens were determined for four anatomical locations in 19 cats of European breed in blind conditions. The densities (±SD) of CD1a+ Langerhans cells in the skin of the abdominal wall (269±68 cells/mm2), the back (363±19), the internal side of the ear (572±30) and the external side of the ear (502±32) were significantly different, with young and old animals displaying less stained cells than adults. No significant differences in the mean densities were found with regard to sex, colour or antibody used.

Electronic Resource

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Human epidermal cells act as stimulators in the mixed-skin cell lymphocyte culture reaction (MSLR). To analyse the generation in MSLR of alloreactive cytotoxic T lymphocytes (CTL) in cell-mediated cytolysis of human epidermal cells, a phenomenon suggested by various observations of skin inflammatory processes in vivo, 18-h 51Cr-release assays against epidermal cells cultivated on collagen-coated plates (epidermal cells autologous to the stimulator cells in MSLR) were conducted after allogenic human MSLR. To analyse the role of human Langerhans cells and related epidermal dendritic cells, which are the only cells expressing the DR-Ia-like (class II) antigens in normal epidermis and in suspensions of normal epidermal cells, MSLR and CTL assays were conducted with, as stimulator cells, suspensions of normal human epidermal cells as controls, and, in parallel, suspensions of epidermal cells after preincubation with anti-class II monoclonal antibody and complement. The generation of alloreactive CTL to epidermal cells occurred only after allogenic MSLR and when targets and stimulator cells were from the same donor; it was abolished when epidermal cell suspensions used in MSLR were depleted in HLA-DR-expressing cells. These findings demonstrate that an epidermal cell-induced generation of cell-mediated cytotoxicity to human epidermal cells may occur in vitro. Langerhans cells and other class II antigen-expressing epidermal cells (dendritic indeterminate cells) are necessary for an optimal in vitro sensitization in MSLR and the subsequent generation of alloreactive CTL towards epidermal cells in man.

Electronic Resource

1600-0560

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Histiocytofibromas (HF) are benign tumours of the skin, the cellular composition of which is not yet known with certainly. The immunohistologic characteristics of 5 lesions were studied by using monoclonal antibodies and an indirect immunofluorescence method. All tumours were found to contain HLA-DR(+) cells, and, to a minor degree, OKM1(+) cells, OKT6(+) cells were present in the epidermis overlying the tumours; however in the HP1 themselves, no OKT6(+) cells were found. The presence of HLA-DR(+) and OKM1(+) cells demonstrates that HF contain cells bearing antigenic characteristics of histiocytes but not of Langerhans'cells, and we feel that the term “histiocytofibroma” is a more accurate designation for these lesions than “dermatofibroma”.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Polarized neutron scattering with polarization analysis on single crystals may allow one to remove some ambiguities in the determination of a magnetic structure, especially for high symmetry systems. The direction of the Fourier components of the magnetic moments and the relative population of different associated magnetic domains are, in particular, obtained. Application is made on a cubic antiferromagnetic rare-earth compound, PrAg. Among the different possibilities, it is proposed that this compound orders in a double-Q (biaxis) magnetic structure with local moments lying along twofold directions.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

ICAM-3 is a newly recognized adhesion molecule, which is a member of the immunoglobulin supergene family of ICAMs. and has been shown to be identical with the CD50 antigen. Recent functional studies have shown that ICAM-3 is a ligand for LFA-1, and plays an important part in immune reactions. To date, very few data exist in the literature concerning its expression in the skin. In the present study, we investigated the expression of ICAM-3 in normal skin and in 98 biopsy specimens of various inflammatory and neoplastic dermatoses. ICAM-3 was found to be expressed by epidermal CD la+ Langerhans cells, by cells of Langerhans cell hisliocytosis, by T and B lymphocytes infiltrating the dermis in cutaneous lymphomas and in a wide spectrum of inflammatory dermaloses. Epidermal keralinocytes were consistently negative: endothelial expression of ICAM-3 was observed in six of the 48 cases. These results show that ICAM-3 is constitutively and widely expressed by cells participating in inflammatory dermaloses (including Langerhans cells and T and B lymphocytes), and that it can be albeit rarely, induced on endothelial cells and dermal dendrocytes. These results highlight the important part that ICAM-3 may play in cutaneous inflammatory and immune reactions.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background The need to develop predictive tests which could identify potential allergens has been recognized for many years. There is as yet no accepted in vitro method for the assessment of contact sensitizers.Objective We have tested the ability of a range of contact allergens to induce in vitro primary sensitization of autologous T cells.Method T-cell proliferation induced by haptens using 2-day cultured human Langerhans cells as antigen-presenting cell was assessed by 3H thymidine incorporation. Antigen specific stimulation was calculated as stimulation indexes. Results Strong allergens induced in vitro a primary T-cell response in all (trinitrophenyl, TNP: 13/13) or in the majority (fluorescein isothiocyanate, FITC: 7/10) of experiments. An irritant, sodium dodecyi sulfate (SDS). failed to generate a significant T-cell proliferation in any of the experiments (0/10). We obtained a significant lymphoproliferative response to weak sensitizers only in a limited number of experiments: (coumarin: 1/12, citronellal: 0/10, hydroxycitronellal: 2/8). p-Phenylenediamine (PPDA), a prohapten and highly sensitizing chemical in vivo, generated primary sensitization in vitro in only one of six experiments, while Bandrowski's base (BB), a metabolization product of PPDA induced a significant T-cell response in all six experiments.Conclusion The present in vitro model allows discrimination between two groups of substances: strong contact sensitizers (TNP, FITC. BB) on the one hand and weak sensitizers (coumarin, citronellal and hydroxycitronellal) and irritants (SDS) on the other hand. It could be used as a screening in vitro assay to eliminate strong contact allergens before further predictive animal tests have to be performed.

Electronic Resource

1600-0560

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

An ultrastructural study of a typical case of acquired perforating dermatosis in a patient with renal failure and diabetes mellitus is reported. Crystal-like microdeposits of an electron-lucid material were detected in the upper dermis, close to the transepidermal channel. Compact macrophage conglomerations surrounded the deposits, and a strong histiocytic response was present. Mononuclear inflammatory cells of “activated”. type penetrated the acanthotie epidermis provoking basement membrane dissolution and widening of interkeratinocyte spaces. Collagen fibers were seen in the keratotic plug, indicating the process of transepidermal elimination. Our observation supports the hypothesis suggesting that some kind of storage phenomenon may be at the origin of perforating skin lesions in renal failure patients.

Electronic Resource

1600-0625

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract In inflammatory dermatoses. activated T cells produce inter-feron-gamma (IFN-γ), which interacts with keratinocytes and contributes to the direct activation of these cells by inducing, among other factors, the expression of HLA-DR antigens and intercellular adhesion molecule-1. However, the action of IFN-γ on epidermal cell cytokine production is not known. Our aim was to assess the effect of IFN-γ on the production of IL-1 by normal human keratinocytes cultured in low calcium medium (MCDB153). In comparison with controls, the addition of nontoxic IFN-yγ concentrations (50-500 U/ml) to cell cultures induced a significant increase of IL-1α and IL-1β production predominantly after 100 U/ml treatment in the cell extracts as well as in the supernatants at 24h and 48h. The production of the antagonist. IL-1RA, was also enhanced and the effect of the critical concentration (100 U/ml) was more evident. However, the absence of a characteristic dose response could not be explained by an antiproliferative effect of high IFN-γ concentrations (250 and 500 U/ml) on cultured keratinocytes or by the induction of the nuclear stress protein, Hsp72. two phenomena known to down-regulate IL-1 biosynthesis. In conclusion, the modifications in keratinocyte IL-1 production under IFN-γ stimulation can contribute to activate the epidermal cells and thus involve them in the local immune response.

Electronic Resource