摘要:

AbstractSpectacular success has recently been made towards elucidation of the molecular basis of various forms of epidermolysis bullosa (EB), a group of heritable blistering skin diseases. The information derived from these studies has already had a profound impact in terms of precise diagnosis and classification, early prenatal prediction of the phenotype and genetic counseling in families at risk for recurrence. This review highlights recent progress made in defining the molecular basis of junctional and dystrophic forms of EB and the genotype/phenotype relationships established from these studies. Extensive molecular studies, such as the ones captured in this review, form a foundation for the rational design of gene therapies to counteract these conditions in the future.

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00086.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractSequential biopsies from skin lesions induced by nickel sulphate and sodium lauryl sulphate, respectively, were investigated with respect to expression of extracellular matrix proteins and adhesion molecules on lymphocytes, endothelial cells, and keratinocytes. The majority of the infiltrating lymphocytes expressed VLA‐4, LFA‐1, CD44 and ICAM‐1, a variable fraction expressed Leu‐8 and VLA‐5, and few or no cells were positive for VLA‐1, VLA‐2 and VLA‐6. Noteworthy, was that the infiltrating cells showed a substantial amount of fibronectin but relatively small or negliglible presence of laminin, collagen type IV, IgG, IgA. IgM, and albumin. The fibronectin was associated with cell bodies as well as the area surrounding infiltrating cells. The number of infiltrating cells was larger in biopsies from nickel‐sulphate induced lesions and the infiltrates contained more fibroneclin than biopsies from lesions induced by sodium lauryl sulphate. However, at the single‐cell level, the expression of VLA antigens, LFA‐1, CD44 and ICAM‐1 was similar in both groups. The endothelial cells of skin biopsies from nickel‐sulphate‐induced lesions showed a stronger expression of VCAM‐1, ELAM‐1 and ICAM‐I compared to biopsies from sodium lauryl sulphate‐induced lesions. In the biopsies from nickel sulphate‐induced lesions, the keratinocytes showed a tendency to less VLA‐6 expression. These results suggest that fibroneclin plays a role in lymphocyte extravasatio

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00087.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractHuman melanocytes established in MCDB‐153 culture medium do not express α1‐, β1‐, β‐2 adrenoceptors without extracellular stimulation. The addition of 50×10−9M norepinephrine to the medium causes a time‐dependent induction of α‐1‐adrenoceptors with 4.278 receptors/melanocyte after 24 h. Under the same experimental conditions, the dendricity of melanocytes as well as melanogenesis was unaffected over 60 h. Since keralinocytes hold the full capacity for catecholamine biosynthesis but melanocytes lack this system, the secretion of catecholamines from keratinocytes appears to be of critical importance to the α‐1‐adrenoceptor in melanocytes, underlining the symbiosis of both ce

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00088.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractPsoriasis is characterized by hyperproliferation and impared differentiation of epidermal keratinocytes (KCs). Psoriasis can be treated with derivatives of relinoic acid (RA) and vitamin D3. Analogues of vitamin D3are able to inhibit proliferation and stimulate differentiation of KCs. In contrast, RA inhibits terminal differentiation of KCs. Interactions are known to occur between RA and vitamin D3signalling pathways. The purpose of the present study was to determine the effect of all‐trans RA on the binding of 1,25‐dihydroxy‐vitamin D3(1,25 (OH)2D3) to the vitamin D3, receptor (VDR) of cultured human KCs. Cultured KCs from normal adults were incubated with or without RA (10−9–10−7M) for 4‐24 h. Cells were then harvested, homogenized and ultrasonicated. The extracted protein was incubated with 3H‐1,25 (OH)2D3(0.015‐1.0 nM) with or without 250‐fold excess nonradioactive 1,25 (OH)2D3for 24 h and specific binding was determined by use of the dextran coated charcoal binding assay. Western blot analysis utilizing the monoclonal antibody 9A7γ to VDR was performed on protein extracted from the KCs. The bands resulting from Western blot analysis were visualized by enhanced chemiluminescence. From Scatchard analysis it was found that KCs bind 1,25 (OH)2D3with high affinity (Kd = 0.175 nM). This binding was dose and time dependently inhibited by RA (60% inhibition at 10−7M after 24 h of incubation). By Western blot analysis, RA had no effect on the amount of protein extracted from KCs at any of the RA concentrations tested. In conclusion, these results show that binding of vitamin D3to its receptor of human KCs can be inhibited markedly by RA without effecting the amount of protein. These results are in contrast to results with other cell types in which RA upregulates binding of 1,25 (OH)2D3to the VDR. Because interaction between retinoids and vitamin D3may occur at different levels during signal trans‐duction, it is not possible to predict from our results whether RA will inhibit the effec

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00089.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper demonstrates that epidermal cells in culture produce an activity which can increase the frequency of Ia+epidermal Langerhans cells (LC). This was achieved by treating mice topically with a mixture containing supernatant derived from primary culture of murine epidermis (ES) and a synthetic corticosteroid, triamcinolone acetonide (TAG). The presence of the supernatant in the mixture partially protected the Ia+LC from depletion by the steroid. The Ia+LC frequency increasing activity was measured as the difference between the Ia+LC frequency due to treatment with steroid mixed with supernatant and the Ia+LC frequency due to treatment with steroid mixed with negative control medium. The mean frequency of Ia+LC in epidermis treated with TAC mixed with ES was 606(SD 43) cells/mm2, as compared with 486 (SD 68) cells/mm2in the epidermis treated with TAC mixed with control medium. The activity appeared to be caused by (a) proteinaceous factor(s). A fraction of ES which was retained above a ≥10 KDa molecular weight cut‐off membrane was capable of partially protecting Ia+LC frequency from TAC depletion. Supernatants from cultured lymph nodes, dermis as well as the squamous cell carcinoma lines T7 and T79, but not the human osteosarcoma cell‐line 143B, also contained similar activities. We demonstrate that GM‐CSF also increased the number of Ia+epidermal LC when applied topically to mouse skin in this system. Therefore, using this Ia+LC frequency modulation system, we propose that GM‐CSF is one example of a cytokine which may be involved in the regulation of Ia+LC numbers in epidermis and that epidermal cells produce factors which can increase the number

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00090.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractCorticotropin releasing factor, adrenocorticotropic hormone (ACTH) and alpha‐melanocyte stimulating hormone either inhibit or enhance in a dose‐dependent fashion an interleukin‐4 (IL‐4) driven human IgE synthesisin vitro.Here, we show that culture conditions strongly influence the earlier observed dose‐ and donor‐dependent effects of adrenocorticotropic hormone. The effect of ACTH on IgE synthesis became only apparent late during culture periods, suggesting an indirect effect via the cellular microenvironment rather than by acting directly at the level of B‐cell isotype switching. Thus, we studied other proopiomelanocortin (POMC) derived peptides and neuropeptides known to influence the cellular microenvironment. Indeed, similar modulatory effects on IgE synthesis were also observed by the addition of other proopiomelanocortin‐derived peptides such as α‐, β‐, and γ‐endorphins as well as by the opioid binding pentapeptide Leu‐enkephalin. Furthermore the neuropeptide substance P accentuated an IL‐4 or an IL‐4 and anti‐CD40 antibody driven class switch to IgE. In contrast to ACTH, substance P interfered not only with IgE synthesis but also with the synthesis of the other immunoglobulin isotypes. Thus, systemically acting neuroendocrine peptides such as ACTH and locally acting neuropeptides such as the enkephalins and substance P can modulate the magnitude

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00091.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA method for preparing skin biopsies for cryosectioning was developed to accurately obtain samples from specific areas of the dermis, while minimizing contamination with epidermal tissue. Routine preparation of 6 mm punch biopsies from freshly excised, full‐thickness skin produced contraction and folding of the edges of the biopsy prior to mounting for snap‐freezing and cryosectioning. Sample orientation was ruined, and cryosections were heterogeneous with respect to dermal structures and/or to dermal and epidermal layers. Biopsy artifacts were prevented by prefreezing skin over dry ice prior to taking biopsies. The biopsies were held frozen on dry ice until they were mounted on cryostat pegs with flattened, frozen OCT surfaces; then they were snap‐frozen in chilled OCT in an isopentane bath cooled with liquid nitrogen. The method for determining skin level homogeneity of cryosections consisted of taking 10 μm cryosections for histology between sections sampled for drug level analysis. The histological sections were fixed in 5% acetic acid in methanol and stained with hematoxylin and eosin to define the skin layers and structures associated with each sample for analysis. Histological sections from prefrozen skin had fewer processing artifacts, and dermal cryosections free of epidermal contamination were dramatically increased compared to the routine pro

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00092.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractModification of pigmentation and damage of melanocytes are characteristic features of skin colonisation byPityrosporum orbicularehyphae in pityriasis versicolor (PV). The yeast is lipophylic and lipid‐dependent, capable of oxidising unsaturated lipid components of skin surface, i.e. unsaturated fatty acids, cholesterol and squalene (SQ). The oxidation of unsaturated fatty acids gives rise to dicarboxylic acids (DA) which behave,in vitro, as competitive inhibitors of tyrosinase. In this work, we further investigate the oxidase activity ofPityrosporum in vitro, by evaluating (a) the generation of lipoperoxides in cultures supplemented with fatty acids at various degrees of unsaturation; (b) the mechanism of SQ oxidation; (c) the chemical characteristics of some by‐products of lipoperoxidation; (d) the formation of peroxisomes in fungal cells. In cultures supplemented with the saturated palmitic acid (C16:0) and monounsaturated oleic acid (C18:1 n‐9), low amounts of lipoperoxides were detected by a spectrophotometric test, whereas in cultures supplemented with di‐unsaturated linoleic acid (C 18:2 n‐6), significant concentrations were found. Gas chromatographymass spectrometry analyses showed the generation of linoleic acid hydroperoxides both inPityrosporumcultures and following incubation of acetone powder of the fungus with the unsaturated fatty acid, indicating the presence of a lipoxygenase activity in the fungus. In cultures supplemented with linoleic acid plus SQ, and increase of lipoperoxide generation was observed and trans‐trans farnesal and squalene epoxides have been identified. Electron microscopic examinations have evidenced peroxisomes in cells grown in the presence of linoleic acid, whereas they were not delected in cultures supplemented with oleic acid and palmitic acid. The metabolic activities of peroxisomes, through the formation of hydrogen peroxide and the subsequent generation of hydroxyl radicals, may account for the peroxidation of SQ, which is not a substrate of lipoxygenase. Following these results, we propose a mechanism for DA generation byPityrosporummetabolism and hypothesize that the lipoperoxidation process induced by lipoxygenase activity of the fungus may be the key to understanding the clinical appearance of skin manifest

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00093.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractSystemic scleroderma (SSc) is a complex connective tissue disorder of unknown etiology. In early stages of the disease, libroblasts are activated to produce large amounts of collagen with subsequent fibrosis. Collagen metabolism of fibroblasts is modulated by their contact with the extracellular matrix (ECM), which involves distinct receptors on the cell surface, mainly belonging to the integrins. We investigated the expression of collagen receptor α2β1, in SSc and normal fibroblasts, since this receptor has been shown to be utilized by fibroblasts for adhesion to and reorganization of collagen I. 9 strains of scleroderma fibroblasts grown as monolayer cultures were first analyzed with respect to their collagen I expression. 6 of these strains were similar to controls (“low” producers) and 3 strains showed up to 2–3 × higher levels of collagen I mRNA expression (“high” producers). Northern hybridization using a cDNA probe specific for the α2integrin subunit revealed a decrease of the corresponding mRNA in SSc fibroblasts as compared to controls (75% versus 100%). “High” collagen producing cell strains displayed the lowest values for α2integrin mRNA. The decrease of α2integrin subunit expression at the mRNA level in selected fibroblasts was further substantiated by radioimmunoprecipitation using specific mAbs directed against α2integrin subunit. No significant changes in β1integrin expression could be observed‐neither at mRNA nor at the protein level. Our data indicate a correlation between excessive synthesis of collagen and low levels of α2integrin subunit expression in SSc fibroblasts. Further experiments should clarify whether this observation is a phenomenon specific for scleroderma or whether it reflects an “activ

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00094.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1996.tb00095.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY