bluuebunny/crossref_metadata_2025 huggingface dataset:
ACKNOWLEDGING A HIDDEN GOD: A THEOLOGICAL CRITIQUE OF STANLEY CAVELL ON SCEPTICISM
Authors: TONNING JUDITH E.
Published: May 2007

In his early work, the philosopher Stanley Cavell offers a sustained engagement with the threat of epistemological scepticism, shaped by the intuition that although (as the late Wittgenstein shows) ordinary language use is the practice within which alone meaning is possible (and which can thus not be further analysed or rationalised), it is also a basic human inclination to wish to escape the limitations of the ‘ordinary’. This, for Cavell, is the root of scepticism. Scepticism, on this view, thus appears not primarily as an epistemological but as an (injurious) moral stance, which cannot be refuted but must be continually confronted and overcome. Vis‐à‐vis scepticism, ‘acknowledgement’ is the practice‐based recognition of the world and other people in their continuing elusiveness, which ineluctably involves risk, but just so is the only way of knowing that is appropriate to and honours the (finite) human condition. One problematic aspect of this (very fertile) approach is that Cavell's secular viewpoint makes it difficult for him to say both why the desire for a ‘beyond’ arises in the first place, and why its expression as denial is morally wrong (rather than merely misguided). His approach thus invites a theological ‘supplementation’ which grounds the human condition in an original and real relation to God that is meant to draw the believer, through Christ, into the divine life itself. Such a reinterpretation both elucidates the concepts of scepticism and acknowledgement, and makes these concepts available for a theological outlook that is able to accommodate Cavell's profound insights into ‘the human’.
Pharmacological and clinical evidences on the potential for abuse and dependence of propofol: a review of the literature
Authors: Roussin Anne , Montastruc Jean‐Louis , Lapeyre‐Mestre Maryse
Published: May 2007

Propofol (2,6‐diisopropylphenol) is an intravenous short‐acting anaesthetic widely used for inducing and maintaining anaesthesia. Propofol is also being increasingly used for sedation. Beside medical use, propofol is abused for recreational purpose, mostly in medical professionals who are not informed of the risk of dependence to this compound. The aim of this review was to provide an overview of molecular, animal and clinical pharmacological data of the literature evidencing the potential for abuse and dependence of propofol.
Breeding performance and longevity of Tomicus destruens on Mediterranean and continental pine species
Authors: Faccoli Massimo
Published: May 2007

The pine shoot beetle Tomicus destruens (Wollaston) (Coleoptera: Curculionidae: Scolytinae) is one of the main pests of Mediterranean forests, where it is oligophagous on Mediterranean pines. However, possible global warming may make the insect move to higher latitudes and altitudes, allowing it to attack new pine species. In this respect, the aim of the present article was to assess both the acceptance and performance of T. destruens offered host and non‐host pine species. A no‐choice breeding experiment was set up under laboratory conditions, using logs of three Mediterranean (Pinus pinea L., Pinus pinaster Miller, and Pinus halepensis Aiton) and two continental (Pinus nigra Arnold and Pinus sylvestris L.) pine species. Log debarking at the end of adult emergence assessed parent fecundity, egg, and larval mortality. The quality of callow adults emerging from each tested pine was evaluated on the basis of their longevity on a semiartificial diet. Tomicus destruens colonised all tested pine species, but did not reproduce in Scots pine, taking about 79 days to complete development with no differences among pines tested. The best breeding performance, evaluated as female fecundity and adult production, was observed in P. halepensis, and the lowest in P. pinaster. On average, adults emerging from P. pinea survived longer (83 days) than from other pines, and adult longevity was the lowest in males emerging from P. nigra. Austrian pine, which under natural conditions is usually not a host of T. destruens, allowed insect development and adult production similar to P. pinea and P. pinaster.
In vitro metabolism by human skin and fibroblasts of retinol, retinal and retinoic acid
Authors: Bailly J. , Crettaz M. , Schifflers M. H. , Marty J. P.
Published: May 2007

The metabolism of radio‐labelled retinol, retinal and retinoic acid by fresh human skin as well as by human dermal fibroblasts have been investigated in vitro. Surgically removed human skin biopsies were placed at the air‐liquid interface, and treated topically for 24 h with retinoids. At the end of the treatment period, epidermis and dermis were separated by heat. Epidermis, dermis and medium were subsequently extracted and resulting fractions were analysed by HPLC. Dermal fibroblast cultures were treated and analysed in a comparable manner. Topical application of retinoids resulted in gradient concentrations within the skin. For each fraction, metabolites and unchanged product proportions were determined by HPLC. After treatment with retinol and retinal, low but significant amounts of retinoic acid were detected in the epidermis, as well as in the dermis (30 pmol to 90 pmol). In comparison, treatments with retinoic acid itself, led to higher level of retinoic acid in the epidermis and in the dermis (respectively 2050 and 420 pmol). Cultured human dermal fibroblasts, treated with retinol and retinal, formed retinoic acid as well as several other metabolites (retinol esters, reduction of retinal to retinol…). Taken together, our results are consistent with an action of retinol or retinal on the skin via a retinoic acid formation and a metabolic function of the dermis.
Hemidesmosomal variants of epidermolysis bullosa
Authors: Pulkkinen L. , Uitto J.
Published: May 2007

Abstract: Epidermolysis bullosa (EB), a heterogeneous group of genodermatoses, is characterized by fragility and blistering of the skin, associated with characteristic extracutaneous manifestations. Based on clinical severity, constellation of the phenotypic manifestations, and the level of tissue separation within the cutaneous basement membrane zone, EB has been divided into distinct subcategories. Traditionally, these include the simplex, junctional and dystrophic variants of EB. Recent attention has been drawn to variants of EB demonstrating tissue separation at the level of hemidesmosomes, ultrastructurally recognizable adhesion complexes within the cutaneous basement membrane zone. Clinically, these hemidesmosomal variants manifest either as generalized atrophic benign epidermolysis bullosa (GABEB), EB with pyloric atresia, or EB with late‐onset muscular dystrophy, Elucidation of basement membrane zone components by molecular cloning and development of mutation detection strategies have revealed that the hemidesmosomal variants of EB result from mutations in the genes encoding the subunit polypeptides of the 180‐kD bullous pemphigoid antigen/type XVII collagen, the α6β4 integrin, or plectin, respectively. Collectively, these data add to the understanding of the molecular complexity of the cutaneous basement membrane zone in EB, as attested by the fact that mutations in 10 different genes can underlie different variants of EB. Elucidation of mutations in different forms of EB has direct application to genetic counseling and DNA‐based prenatal testing in families with EB.
Controversies in Experimental Dermatology: What exactly is “atopy”?
Authors: Röcken M. , Schallreuter K. , Renz H. , Szentivanyi A.
Published: May 2007

Several decades ago, Ingram already complained that “Atopy means exactly nothing, except in the mind of Coca and Cooke”. Despite very substantial progress in basic and clinical research on the atopic diseases, particularly in the areas of immunogenetics, cellular immunology and immunopharmacology, there is still a great deal of uncertainty, confusion and conflict on what exactly the basic underlying abnormality of the atopic diseases may be. Therefore, this inaugural feature of Controversies in Experimental Dermatology illustrates the ongoing dispute on one of the unsolved key problems of experimental and clinical dermatology, and sketches promising avenues for future research.
Molecular basis of non‐lethal junctional epidermolysis bullosa: identification of a 38 basepair insertion and a splice site mutation in exon 14 of the LAMB3 gene
Authors: Cserhalmi‐Friedman P. B. , Baden H. , Burgeson R. E. , Christiano A. M.
Published: May 2007

Abstract: Epidermolysis bullosa (EB) is a group of genodermatoses characterized by fragility and easy blistering of the skin. In the junctional forms of EB (JEB), blisters occur at the level of the lamina lucida, and specific mutations have been detected in the genes encoding different components of the hemidesmosomal‐anchoring filament complex. In the non‐lethal form of JEB (NL‐JEB), mutations in genes encoding two of the polypeptide chains of the anchoring filament protein laminin 5 have recently been described. In this study, we searched for mutations in a family using PCR amplification of exon 14 of LAMB3, the laminin 5 β3 chain gene, followed by heteroduplex analysis and automated sequencing of the PCR products. We detected a novel combination of mutations in this family, consisting of an out‐of frame insertion on one allele, and a splice site mutation on the other allele, representing the first report of a large insertion in LAMB3, together with a splice site mutation inherited in trans, which result in the NL‐JEB phenotype.
Decreased frequency of interferon‐γ‐ producing CD4+ cells in the peripheral blood of patients with atopic dermatitis
Authors: Nakagawa S. , Aiba S. , Tagami H.
Published: May 2007

Abstract: Recently, decreased interferon ‐ γ (IFN‐γ) and increased interleukin (IL)‐4 production have been reported in measurements of the content of the cytokines in culture supernatants of peripheral blood mononuclear cells (PBMC) obtained from patients with atopic dermatitis (AD). These data suggest deviation of PBMC into Th2‐reactive cells in AD. In the present study, we examined the frequency of IL‐2‐, IL‐4‐, and IFN‐γ‐ producing cells in PBMC with flow cytometry. PBMC from 16 patients with AD and 18 healthy controls were stimulated for 2 days with anti‐CD3 and IL‐2, and further cultured for 4 days with a maintenance dose of IL‐ 2. Thereafter these cells were restimulated with phorbol 12‐myristate 13‐ acetate (PMA) and ionomycin for 4 h in the presence of monensin. After fixation of the cells, the cell membranes were made permeable and intracellular cytokines were stained with anti‐IL‐2, anti‐IL‐4 or anti‐IFN‐γ antibody. Cytokine‐producing cells were analyzed by gating CD4+ ‐ or CD8+ ‐subsets. Thus counted frequency of IFN‐γ‐producing cells was significantly decreased in CD4+ subsets of AD patients (9.9±7.4%) when compared with that in the controls (20.0±6.7%). There was no significant difference either in the frequency of IL‐2‐ or IL‐4‐producing CD4+ subsets or in that of CD8+ subsets. Furthermore, in the enzyme‐linked immunosorbent assay, we also found a decreased production of IFN‐γ in the culture of PBMC from AD patients, when compared with those from healthy controls, although it was only at a marginally significant level (P= 0.07). Again there was no increase in IL‐4 concentration in AD patients. In addition, we found a weak negative relationship between the disease severity and the frequency of these cells. These results suggest that the decreased frequency of IFN‐γ‐producing CD4+ cells with subsequently decreased production of IFN‐γ play a crucial role in the pathophysiology of AD.
CD8+ cytolytic T lymphocytes and the skin
Authors: Panfilis G. De
Published: May 2007

Abstract: T lymphocytes show a special affinity for the skin. Although the roles played by the CD4+ population of T lymphocytes in immunodermatology were so far actively investigated, much less is known about the roles played in the skin by CD8+ cytolytic T lymphocytes (CTL). The activity of CD8+ CTL in the immunodermatological context, however, is likely to be most important; the immuno‐biology itself of CD8+ CTL, moreover, although far from being fully understood, shows intriguing characteristics. Immunophenotype, function and cytokine profile of CD8+ CTL are overviewed in the first section of this review. Phenotypically, not only CD8+ CTL can be subdivided into CD8+ CD28+ CD11b+ and CD8+ CD28‐ CD11b+ subsets, but also an up‐to‐now undetected CD8+ CD28‐ CD11b‐ subset does exist. Functionally, not only “cytotoxic” but even “suppressor” subpopulations have been shown to exert cytolytic capabilities indeed, and “suppression” itself may be due to such a lytic capacity. According to cytokine synthesis, CD8+ CTL can be split into Tc1 and Tc2 subsets, each able to influence specific patterns of immune responses. The impact of CD8+ CTL in immunodermatology, overviewed in the second section of the current review, is crucial. The pathophysiology of inflammatory dermatoses is deeply influenced by the activity of CD8+ CTL: e.g., CD8+ CTL within psoriateic epidermis are possibly associated to the persistence of psoriatic lesions not undergoing resolution; on the other hand, in late lesions of lichen planus CD8+ CTL predominate, thus explaining presumably both the cytolytic attack against keratinocytes and the modulation of the inflammatory reaction up to the final resolution of the lesions; Tc1 cells are decreased in atopic dermatitis, and such a decrease can account both for IgE overproduction and for development of infections. Finally, CD8+ CTL can sustain against cutaneous viruses/tumors cytolytic immune responses not only of secondary but even of primary type, i.e. induced by Langerhans cells/dendritic cells either transfected or pulsed with skin virus/tumor‐associated antigens, thus allowing the production of vaccines against cutaneous viral/neoplastic diseases.
The millennium criteria for the diagnosis of atopic dermatitis
Authors: Bos J. D. , van Leent E. J. M. , Smitt J. H. Sillevis
Published: May 2007

Abstract: Atopic dermatitis forms an active area of basic and clinical research, where important new knowledge about genetics and immunopathogenesis has surfaced over the past years, and where simultaneous development of new and innovative therapies is under way. However, the inclusion of any patient in an atopic dermatitis study, whether it is on its genetics, pathogenesis or therapy, requires a diagnosis which is irrefutable. Since there is no simple and also no complicated laboratory procedure to reach a diagnosis of atopic dermatitis, different sets of clinical criteria have been developed for the purpose of making the diagnosis uniformly in different studies as well as in different study centers. The most commonly used are Hanifin and Rajka's set of diagnostic features, which have major and minor clinical criteria to be fulfilled in order to establish a diagnosis of atopic dermatitis. Recent developments in the immunology of atopy have clearly established the major abnormality in this syndrome, the preferential production of allergen‐specific IgE. In this contribution, it is suggested that the presence of such antibodies in a given patient should be a mandatory criterium for the diagnosis of atopic dermatitis. Such a diagnostic test however establishes a diagnosis of atopic syndrome, not atopic dermatitis. Thus, for atopic dermatitis we have to rely, for the time being, on additional clinical criteria. The clinical features described in the literature are critically evaluated, and it is suggested that in addition to the mandatory presence of allergen‐specific IgE, 2 of 3 principal criteria (pruritus, typical morphology and distribution, chronic or chronically relapsing) should be present for such a diagnosis. Finally, the minor features originally described by Hanifin and Rajka and later evaluated by others are revised and divided over 4 subcategories; a) related to subclinical eczema; b) related to dry skin; c) extra skin folds; and d) ophthalmological pathology. They are suggested to be used as additional criteria only, needed when clinical suspicion is high but the new mandatory and principal diagnositic criteria described here are inconclusive. For study purposes, we suggest that the mandatory and principal criteria are sufficient. They are now evaluated and validated in ongoing atopic dermatitis treatment studies.
Most chronic urticaria is food‐dependent, and not idiopathic
Authors: Henz B. M. , Zuberbier T.
Published: May 2007

Abstract: Although chronic urticaria is generally thought to be mostly idiopathic, we have recently provided convincing evidence that in the majority of patients, food ingredients provoke the symptoms and sustain the disease. On a diet largely avoiding preservatives, dyes and natural pseudoallergens, 73% of patients experienced remission of more than 6 months duration, starting within the first 3 weeks after initiation of the diet. This response rate is clearly higher than the reported 24% spontaneous remission rate over the same time period. The specificity of the dietary effect was proven 1) by double‐blind provocation with pureed pseudoallergen‐low versus ‐rich food and 2) by induction of a clinical response to a 3‐week diet low in pseudoallergens, but not to a standard diabetes diet in 3 patients studied in a double‐blind crossover design. On double‐blind, placebo controlled oral provocation, only 18% of diet‐responsive patients reacted to known food preservatives and dyes, but 71% to pureed tomatoes and 44% to their steem extracts. These findings identify naturally occurring pseudoallergens in food as major elicitors of chronic urticaria. In contrast, autoantibodies against Fc‐RIα have been identified in only about 30% of chronic urticaria patients, and evidence for their truly causative role is still lacking since therapeutic measures work in patients irrespective of the presence or absence of the autoantibodies. For both food intolerance and Fc‐RIα‐autoantibodies in chronic urticaria, the associated pathomechanisms are however still in need of clarification. Meanwhile, the diet‐responsiveness in the majority of patients opens new perspectives for the management of chronic urticaria.
What controls melanogenesis?
Authors: Schallreuter K. , Slominski A. , Pawelek J. M. , Jimbow K. , Gilchrest B. A.
Published: May 2007

The pigments eumelanin and pheomelanin are the visually most striking products of specialized neural crest‐derived cells (melanocytes), and provide color to both epidermis and hair shafts. While the intriguing and controversial biological functions of these multifaceted heteropolymers will be discussed in a later feature, here it is explored how their generation (melanogenesis) is controlled. For decades, this has been the object of much controversy, the salient features of which are delineated in the following contributions.
Release of monocyte chemoattractants by polymorphonuclear leukocytes stimulated by their adhesion to stratum corneum opsonized via complement activation, measured with a human acute monocytic leukemic cell line, THP‐1
Authors: Ozawa M. , Terui T. , Tanita M. , Kato T. , Tagami H.
Published: May 2007

Abstract: Stratum corneum (SC) exposed to living tissues, induces inflammation characterized by the formation of mixed cell granulomas consisting of infiltrative polymorphonuclear leukocytes (PMNs) and monocytes/macrophages. In this study, to clarify the mechanism for the later monocyte accumulation in SC‐induced granulomas, we evaluated monocyte chemotactic activity induced by PMNs treated with serum‐opsonized SC by using a human acute monocytic leukemic cell line, THP‐1. When the supernatant was obtained from a PMN suspension cultured with opsonized plantar SC, higher THP‐1 chemotactic activity was detected as compared with that cultured with non‐opsonized SC. Although some concentrations of the chemokines, MIP‐1α and MIP‐1β, were detected in supernatants obtained from the PMN suspensions cultured with plantar SC than in the control suspensions of PMN alone, their production by PMN was not influenced by the opsonization procedure. In contrast, MCP‐1 was found to be secreted from PMN suspensions constitutively, showing no correlation to this THP‐1 chemotactic activity. Moreover, HPLC analysis of PMN suspensions indicated that factors with far higher molecular weight values than these chemokines are involved in the chemotaxis of THP‐1 cells.
Decreased Interleukin‐7 and transforming growth factor‐beta1 levels in blister fluids as compared to the respective serum levels in patients with bullous pemphigoid: Opposite behavior of TNF‐alpha, Interleukin‐4 and Interleukin‐10
Authors: Giacalone B. , D'Auria L. , Bonifati C. , Ferraro C. , Riccardi E. , Mussi A. , D'Agosto G. , Cordiali‐Fei P. , Ameglio F.
Published: May 2007

Abstract: This study analyzes both the blister fluid (BF) and serum levels of IL‐7 and TGF‐beta1 in samples from 18 patients affected with bullous pemphigoid (BP). These cytokines clearly present lower concentrations (P<0.001) in BFs than in the sera (1/20 and 1/2, respectively). In contrast, TNF‐alpha, IL‐10 and IL‐4 present increased amounts in BFs that were 12, 12 and 17‐fold, respectively. Eighteen sera (and 10 suction BF) from normal individuals were also employed as control. Normal sera presented significantly lower serum IL‐7 concentrations than BP, while no significant TGF‐beta1 variations were observed between normal and pathologic serum samples. In addition, the serum levels detected in BP patients were significantly correlated with disease intensity (r=0.64, P=0.003, evaluated as the number of blisters/erosions for each patient) as well as with the peripheral B‐lymphocyte counts (r=0.80, P<0.001) and antibodies directed against the basement membrane zone (r=0.65, P<0.005). Although a clear explanation of this phenomenon is lacking, the data presented in this report agree with a strong decrease of IL‐7 production at the local level (keratinocyte is known to produce IL‐7 and the latter is known to be down‐regulated by IL‐10, and in other models also by TGF‐beta1 and IL‐4, whose levels are elevated in BP BFs) as opposed to an increased peripheral release of the same modulator. The IL‐7 reduction may have a biological relevance in controlling a chronic, progressive disease.
Cell migration and MMP‐9 secretion are increased by epidermal growth factor in HaCa T‐ras transfected cells
Authors: Charvat Sandrine , Chignol Marie‐Christine , Souchier Catherine , Griel Caroline Le , Schmitt Daniel , Serres Mireille
Published: May 2007

Abstract: Mutated RAS oncoproteins and epidermal growth factor (EGF) are thought to contribute to the proliferative, invasive and metastatic properties of transformed cells. In the present study, we investigated the role of EGF in two H‐ras transfected clones and compared it to that in the parental cell line, HaCaT and primary cultured keratinocytes. Our findings show that the motility on type I collagen, measured by the migration index, was similar for both the HaCaT cell line and normal human keratinocytes, whereas it was higher for the HaCaT‐ras clones. These results suggest an involvement of the ras oncogene in the stimulation of cell migration. EGF, in cell pretreatment or during the migration assay also caused an increase in migration of all the cells, but preserved the difference between HaCaT and HaCaT‐ras. However, no significant difference in EGF‐R expression was detected between normal cultured keratinocytes, HaCaT and HaCaT‐ras cell lines with or without EGF pretreatment. Moreover, when the cells were stimulated with EGF, the MMP‐9 activity was greatly increased in a dose‐dependent manner in all the cells, and EGF stimulation particularly highlights the increased amount of MMP‐9 in HaCaT‐ras cells compared to HaCaT cells. In conclusion, EGF is able to enhance motility and to up‐regulate MMP‐9 activity in all cells, but with a higher impact in HaCaT‐ras cells without an overexpression of EGF‐R. As EGF acts in synergy with the H‐ras mutation, they could be implicated in the local invasion by the HaCaT‐ras clones.
A novel in‐situ‐zymography technique localizes gelatinolytic activity in human skin to mast cells
Authors: Krejci‐Papa N. C. , Paus R.
Published: May 2007

Abstract: Matrix‐metallo‐proteinases play a key role in cutaneous tissue remodeling and wound healing, and have been implicated as the ratelimiting factor in cutaneous tumor invasion and metastasis. We here describe a novel in‐situ‐zymographic method, which allows to directly localize sites of gelatinolytic activity in human skin. Gelatinolysis was detected through protein‐hydrolysis in a 200 μm thick polyacrylamide gel underlying tissue sections. The lysis was substrate‐dependent, demonstrated time‐ and temperature‐dependent kinetics, and was inhibited by both EDTA and 1,10‐phenanthroline. Normal and diseased skin sections demonstrated multiple focal points of gelatinolysis which co‐localized with individual cells. Histochemically, these were shown to represent most likely mast cells (via AS‐d‐chloroacetate esterase staining and metachromasia). However, immunohistochemical staining for gelatinases A and B showed no immunoreactivity patterns that corresponded to the identified foci of gelatinolysis. The reported in‐situ‐zymographic technique offers a decisive advantage over immunohistochemistry, since it detects only the activated and catabolically relevant proteases, and provides further evidence for a role of mast cells in extracellular matrix remodeling.
An increased ratio of interleukin‐1 receptor antagonist to interleukin‐1α in inflammatory skin diseases
Authors: Terui T. , Hirao T. , Sato Y. , Uesugi T. , Honda M. , Iguchi M. , Matsumura N. , Kudoh K. , Aiba S. , Tagami H.
Published: May 2007

Abstract: IL‐1 receptor antagonist (IL‐1ra) is a cytokine that competitively binds the IL‐1 receptor to antagonize IL‐1 activity without any agonist function. Previous experiments indicated that the ratio of IL‐1ra to IL‐1α in the normal stratum corneum (SC) was much higher in the sunexposed face than in the sun‐protected area, upper arms. It was also reported by another laboratory that IL‐1ra is increased in the lesional skin of psoriatic patients. This study was designed to measure the contents of IL‐1α and IL‐1ra in non‐lesional and pathological SC obtained from inflammatory skin diseases including psoriasis and non‐psoriatic dermatoses such as atopic dermatitis. The SC materials were obtained with a noninvasive tape‐stripping method. Their soluble fractions were prepared and assayed for IL‐1α and IL‐1ra by enzyme‐linked immunosorbent assays. As a result we confirmed the previous findings that the ratio of IL‐1ra to IL‐1α in the normal SC was much higher in the face than in the sun‐protected sites, the trunk as well as extremities. Next, we found that IL‐1α contents were significantly reduced in the SC samples obtained from inflammatory skin regardless of whether their IL‐1ra contents increased or unchanged. Moreover, we noted that an increased ratio of IL‐1ra to IL‐1α in the SC was not specific to psoriasis, but was also found in other inflammatory skin diseases including atopic dermatitis. This ratio was found to become lower after successful treatment of these skin lesions with topical glucocorticoids. We conclude from these observations that the increased ratio of IL‐1ra to IL‐1α in the SC is a non‐specific phenomenon that can occur in any inflammatory skin diseases regardless of the inflammatory pattern, probably reflecting a skin regulation process against various kinds of inflammation.
Lack of intrinsic polarity in the ligandbinding ability of keratinocyte β1 integrins
Authors: Bishop L. A. , Kee W. J. , Zhu A. J. , Watt E. M.
Published: May 2007

Abstract: Within the basal layer of the epidermis the β1 integrins have a pericellular distribution. Two monoclonal antibodies, 15/7 and 12G10, that detect a conformation of the β1 integrin subunit that is induced following cation or ligand occupancy selectively recognized β1 integrins at the basement membrane zone in vivo and in focal adhesions of cultured keratinocytes; they did not recognize integrins on the apical and upper lateral membranes of basal keratinocytes nor integrins on the suprabasal keratinocytes of hyperproliferative epidermis. Inhibition of intercellular adhesion did not induce the 15/7 epitope on the lateral and apical membrane domains. The surface distribution of the epitopes was consistent with the antibodies acting as reporters of ligand‐binding; in addition, the 15/7 epitope was exposed on unglycosylated, immature β1 integrins. Although the apical membrane of basal keratinocytes is not normally in contact with extracellular matrix proteins, we found that it was capable of binding fibronectin‐coated beads and that the 15/7 epitope was exposed on plasma membrane in contact with the beads. When a chimeric molecule consisting of the extracellular domain of CD8 and the cytoplasmic domain of the β1 integrin subunit, used to mimic a constitutively active β1 heterodimer, was introduced into keratinocytes it localized to the basal, lateral and apical membrane domains. We conclude that although the conformation of the keratinocyte β1 integrins differs between the basal and the lateral/apical membrane domains there is no intrinsic polarity in the ligand binding potential of the receptors.
Keratinocytes and dermal factors activate CRABP‐I in melanocytes
Authors: Sanquer S. , Reenstra W. R. , Eller M. S. , Gilchrest B. A.
Published: May 2007

Abstract: Recognition that cellular retinoic acid binding protein (CRABP)‐I and CRABP‐II are found in different cell types has provided additional support for the presumably divergent roles of these two proteins in mediating retinoic acid (RA) effects in human skin. CRABP‐II is expressed in fibroblasts and keratinocytes, and CRABP‐I in as yet unidentified cells, possibly epidermal melanocytes. Recently, we demonstrated that each of these RA‐binding proteins in human skin possesses two classes of binding sites, possibly related to the state of phosphorylation of the proteins. We now characterize the cutaneous origin of CRABP‐I further using an anion‐exchange HPLC assay that allows effective separation of the two proteins in human skin, and a fluorescent in situ hybridization technique. We report that CRABP‐I is expressed in isolated melanocytes at the mRNA level, although under these circumstances the protein has minimal RA‐binding activity, and that keratinocytic and dermal influences are required for CRABP‐I activity in melanocytes. This melanocyte origin for CRABP‐I and the improvement by RA of the irregular hyperpigmentation associated with photoaging led us to examine the effects of RA using various cellular associations, from conventional pure cultures of melanocytes grown on plastic dishes to a pigmented skin equivalent consisting of melanocytes and keratinocytes grown on a dermal equivalent. We established that the inhibitory effects of RA on melanogenesis do not result from a direct effect on melanocytes alone but also involve keratinocytes and dermal influence. These data expand our understanding of cell‐to‐cell signaling in cutaneous pigmentation, and strongly suggest a role for CRABP‐I in mediating RA effects on melanogenesis.
Analysis of the desmoplakin gene reveals striking conservation with other members of the plakin family of cytolinkers
Authors: Green K. J. , Guy S. G. , Cserhalmi‐Friedman P. B. , McLean W. H. I. , Christiano A. M. , Wagner R. M.
Published: May 2007

Members of the plakin family of cytolinker proteins integrate filaments into cellula networks and anchor these networks to the plasma membrane. Their importance is supported by the existence of cell and tissue fragility disorders caused by mutations in certain family members. In this study, the human gene encoding desmoplakin (DSP) was characterized and its structure compared with the related family members: plectin, bullous pemphigoid antigen 1 (BPAG1), envoplakin (EVPL) and periplakin (PPL). Sequence analysis of genomic clones was carried out in combination with a PCR‐based strategy to define intron‐exon border. DSP was mapped using the GB4 radiation hybrid mapping panel to the interval between markers D6S296 and AFM043Xf2, correponding to cytogenetic band 6p24. In addition, the murine gene (DSP) was mapped to mouse chromosome 13 by interspecific backcross mapping. DSP encompasses 45 kb organized into 24 exons and 23 introns, and the pattern of intron‐exon borders bears a striking resemblance to other member of the plakin family. Notable features include the fact that a single large exon encodes the entire C‐termius of each gene. In contrast, the N‐termini comprise numerous smaller exons with conservation of many genses will facilitate their further evaluation as targets of genetic disorders and provide insights into the evolutionary relationships among molecules in this emerging gene family.
Maturation of epidermal Langerhans cells: increased experssion of β‐and γ‐actin isoforms as a basis of specialized cell functions
Authors: Ross R. , Ross X. L. , Längin T. , Reske‐Kunz A. B.
Published: May 2007

Epidermal Langerhans cells (LC) represent immature dendritic cells. During in vitro culture in the presence of keratinocytes they mature into potenet immunostimulatory cells for naive T cells. This process is thought to simulate in vivo maturation of LC following activation by antigen contect. Maturation of LC is accompanied by morphological alteration. Applying a differential screening procedure we isolated differentially expressed cDNAs involved in the maturation events including cDNAs of the cytoskeletal actin isoforms β‐and γ‐actin. Stronger signals with hybridization probes derived from cultured LC compared with probes derived from freshly isolated LC indicate upregulation of actin expression. Upregulated expression of actin was confirmed by RT‐PCR, Western blot and immunofluorescence analysis. Staining with flurescence‐labelled and increase in F‐actin levels in cultured LC. Thus our data show that maturation of LC, which involves formation of dendritic structures and movement of formerly immobile cell, is accompanied by augmented expresion of actin and formation of additional actin filaments. Furthermore, actin mRNA, often used as reference to assess mRNA amounts for Northern blotting or competitive RT‐PCR because of its high and ubiquitous expression is an inappropriate standard for the analysis of LC and DC.
Epidermolytic hyperkeratosis with polycyclic posoriasiform plaques resulting from a mutation in the keratin 1 gene
Authors: Michael E. J. , Schneiderman P. , Grossman M. E. , Christiano A. M.
Published: May 2007

Epidermolytic hyperkeratosis (EHK) is a genodermatosis caused by mutations in either the keratin 1 (K1) or keratin 10 (K10) genes, and characterized by erythroderma and blistering at birth, with development of a ribbed, ichthyotic hyperkeratosis and palmoplantar keratoderma. A wide variety of mutations within the highly conserved helix termination motifs of the central rod domains of the K1 or K10 genes correlate with the highly variable phenotypic severity observed in EHK. We report a unique EHK‐like phenotype exhibiting autosomal dominant inheritance with variable expressivity in four affected individuals in a single family. Clinically, affected individuals manifest transient blistering at birth followed by chronic diffuse palmoplantar keratoderma without transgradiens. Intermittent flares of non‐migratory polycylic erythematous psoriasiform plaques which worsen and abate in severity were present in all affected individuals, but showed immense individual variation in both severity and duration, ranging from weeks to months. Histopathologic examination of the psoriasiform plaques demonstrated the characteristic features of EHK. Sequencing of the K1 gene in affected family members revealed a heterozygous A‐to‐T transversion at nucleotide 1435 within exon 7, converting isoleucine (ATT) to phenylalanine (TTT), (I479F). The mutation resides within the highly conserved helix termination motif of the helix 2B segment of the K1 gene. This unique clinical phenotype and the associated K1 mutation have not been previously described, and the associated K1 mutation have not been previously described, and it is referred to here as EHK with polycyclic, psoriasiform plaques (EHK/PPP).
Effect of type XII or XIV collagen NC‐3 domain on the human dermal fibroblast migration into reconstituted collagen gel
Authors: Akutsu N. , Milbury C. M. , Burgeson R. E. , Nishiyama T.
Published: May 2007

Abstract: Type XII and XIV collagens localize near the surface of banded collagen fibrils and most likely work as a molecular bridge between collagen fibrils. We have shown that both collagens can modulate the interactions between collagen fibrils, allowing fibroblasts to act upon the fibrils to vary the deformability. In the present study the effect of the globular domains (collagenase‐resistant domains) of type XII and XIV collagens (XII‐NC‐3 and XIV‐NC‐3) on the migration of fibroblasts into the reconstituted type I collagen gel was investigated. Cell attachment and proliferation on the collagen gel were unaffected. The migration of fibroblasts into the gel was increased proportionally to the concentration of collagen. We found that XII‐NC‐3 and XIV‐NC‐3 domains caused decreases in the numbers of fibroblasts that migrated into the gel. Heat treatment of XII‐NC‐3 and XIV‐NC‐3 or the addition of polyclonal antibodies eliminated the suppressive activity on fibroblast migration, showing that the intact conformation of NC‐3 domain is important for suppression of migration. The results suggest that both NC‐3 domains influence the deformability of type I collagen fibril networks, which may cause the change in fibroblast migration.
Structural changes of human epidermis induced by human leukocyte‐derived proteases
Authors: Ludolph‐Hauser D. , Schubert C. , Wiedow O.
Published: May 2007

Abstract: During the process of inflammation human neutrophils release potent serine proteases, such as human leukocyte elastase and cathepsin G. In psoriasis these enzymes are relased within the epidermis. To investigate the destructive potential of neutrophil‐derived serine proteases these were applied on viable human epidermis as well as full thickness human skin in vitro. Human leukocyte elastase and cathepsin G were found to dissociate keratinocytes from epidermal sheets in a time‐ and dose‐dependent fashion. Significant keratinocyte dissociation was observed 4 h after application of 3 nM human leukocyte elastase. By electron microscopy of elastase‐or cathepsin G‐treated full thickness human skin, widening of the extracellular space followed by complete separation of keratinocytes without intradesmosomal cleavage was observed. In addition, cathepsin G induced membrane damage as well as destruction of intracellular organelles. Thus, neutrophil‐derived serine proteases exert pronounced destructive potential in human epidermis in concentrations likely to appear in lesional psoriatic skin.
Analysis of cultured keratinocytes from a transgenic mouse model of psoriasis: effects of suprabasal integrin expression on keratinocyte adhesion, proliferation and terminal differentiation
Authors: Romero M. R. , Caroll J. M. , Watt F. M.
Published: May 2007

Abstract: Many important transgenic mouse models of benign and neoplastic skin diseases have been generated through the use of promoters that target transgene expression to the different epidermal layers. However, more mechanistic studies of the specific effects of the transgenes on keratinocytes have been hampered by difficulties in culturing keratinocytes from adult mouse epidermis and by the low differentiation potential of many established mouse keratinocyte lines. We have used the Rheinwald & Green technique to cultivate primary adult keratinocytes and to generate keratinocyte lines from transgenic mice which have a sporadic psoriatic phenotype due to expression of human integrin subunits under the control of the involucrin promoter. We show that the transgenes are induced when keratinocytes are placed in suspension and that the transgenic integrins are capable of clustering in focal adhesions and mediating cell adhesion and spreading. We also show that suprabasal integrin expression has no direct effect on proliferation of cells in the underlying basal layer, ruling this out as a possible explanation for the epidermal hyperproliferation observed in the transgenic mice.
Molecular diagnostics of epidermolysis bullosa: novel pathomechanisms and surprising genetics
Authors: Uitto J.
Published: May 2007

Abstract: Tremendous progress has been recently made in understanding the molecular basis of epidermolysis bullosa (EB), and as of today specific mutations have been delineated in 10 distinct genes in different subtypes of this genodermatosis. Molecular diagnostics of EB has implications for improved classification with prognostic significance, refined genetic counseling, and establishment of DNA‐based prenatal testing. During elucidation of mutations in different variants of EB, novel pathomechan‐ isms, including uniparental isodisomy in junctional EB and de novo dominant mutations in dystrophic EB, have been encountered. These ob‐Jouniservations have relevance to counseling the families of the risk of recurrence of EB in subsequent pregnancies in the same and future generations.
Signal transduction in keratinocytes
Authors: Mitev V. , Miteva L.
Published: May 2007

Abstract: Keratinocytes, a key cellular component both for homeostasis and pathophysiologic processes of the skin, secrete a number of cytokines and their proliferation and differentiation are stimulated by a variety of biological factors. The major mechanism by which cells (keratinocytes) re‐spond to extracellular signals, is changing in protein phosphorylation. The protein phosphorylation is a consequence of the ligand/receptor bind‐differentiation ing which leads to activation of several transduction systems. In this re‐view we emphasize on different signal transduction pathways in kera‐ tinocytes (tyrosine kinases, PKA, PKC, MAPK, casein kinase 2 etc.).
Identification of sporadic mutations in the helix initiation motif of keratin 6 in two pachyonychia congenita patients: further evidence for a mutational hot spot
Authors: Lin M. T. S. , Levy M. L. , Bowden P. E. , Magro C. , Baden L. , Baden H. P. , Roop D. R.
Published: May 2007

Abstract: Pachyonychia congenita (PC) is a rare, autosomal dominant, ectodermal dysplasia characterized most distinctly by the presence of symmetric nail hypertrophy. In the Jadassohn‐Lewandowsky form, or PC‐1, additional cutaneous manifestations may include palmoplantar hyperkeratosis, hyperhidrosis, follicular keratoses, and oral leukoker‐atosis. Mutations have previously been identified in the 1A helix initiation motif of either keratin 6 or keratin 16 in patients with PC‐1. In the current study, we have identified 2 sporadic, heterozygous mutations in the 1A helix region of the K6 isoform (K6a). The first mutation identified was a 3 base pair deletion (K6aΔ N171). The second mutation was a C‐to‐A transversion resulting in an amino acid substitution (K6a N171K). These data, in combination with previous reports, provide further evidence that this location is a mutational hot spot.
Novel and recurrent mutations in keratin 10 causing bullous congenital ichthyosiform erythroderma
Authors: McLean W. H. I. , Morley S. M. , Higgins C. , Bowden P. E. , White M. , Leigh I. M. , Lane E. B.
Published: May 2007

Abstract: Bullous congenital ichthyosiform erythroderma (BCIE) is a dominantly inherited keratinizing disorder characterized by erythroderma and blistering in neonates and generalized epidermolytic hyperkeratosis (EH) in adulthood. Previously, it has been shown that BCIE can be caused by mutations in either of the genes encoding K1 or K10, the keratins predominantly expressed in suprabasal layers of the epidermis. Using direct sequencing of genomic PCR fragments, we have analyzed 4 British families with BCIE, all of whom were found to carry mutations in K10. In 1 family, the affected person was found to have an unusual dinucleotide transversion mutation, 2138CCÁ, causing two amino acid substitutions, D155E and R156S, also in the 1A domain of the K10 polypeptide. In 2 further kindreds, the previously reported hotspot mutations 2139C‐T and 2140G‐A were found. These mutations predict amino acid substitutions in the helix 1A domain of K10, designated R156C and R156H respectively. The proband in the fourth family was found to carry a novel mutation 4724T‐C, predicting the amino acid change L452P in the helix 2B domain of K10. All mutations were confirmed in the affected persons and were excluded from a population of 50 normal, unrelated individuals by restriction enzyme analysis. The location of these mutations in the highly conserved helix boundary motif sequences of K10 are consistent with previously reported dominant negative mutations in K10 and other keratins. Despite the unusual nature of two of these mutations, in particular the double missense mutation, the phenotypes of the affected individuals in these 4 families were entirely typical of BCIE.
An asparagine to threonine substitution in the 1A domain of keratin 1: a novel mutation that causes epidermolytic hyperkeratosis
Authors: Arin M. J. , Longley M. A. , Küster W. , Huber M. , Hohl D. , Rothnagel J. A. , Roop D. R.
Published: May 2007

Abstract: Epidermolytic hyperkeratosis (EHK) is a congenital, autosomal dominant disorder of cornification characterized by hyperkeratosis and blister formation. The clinical manifestations are heterogeneous, with respect to the extent of body surface involvement, palmar and plantar hyperkeratosis and the presence of erythroderma. Point mutations in the genes encoding the suprabasal‐specific keratins, keratins 1 and 10 have been identified in EHK patients. The inappropriate amino acid substitutions cause a collapse of the keratin filament network, resulting in cytolysis of the involved keratinocytes. We report a severe case of EHK with a single base pair mutation that causes a threonine for asparagine substitution in residue 8 (N8T) of the 1A region of the keratin 1 protein. This is the region involved in molecular overlaps between neighboring keratin heterodimers. These findings suggest that even conservative amino acid substitutions in overlap regions can cause tonofilament clumping.
Identification of mutations in the transgluataminase 1 gene in lamellar ichthyosis
Authors: Tok J. , Garzon M. C. , Cserhalmi‐Friedman P. , Lam H. M. , Spitz J. L. , Christiano A. M.
Published: May 2007

Abstract: Lamellar ichthyosis (LI) is an autosomal recessive disorder of cornification. Mutations in the transglutaminase 1 gene (TGM1) have been identified in several families with this disorder. We analyzed two unrelated families with offspring affected with LI. Family 1 included affected monozygotic twins, in which a homozygous G‐to‐T transversion was identified in exon 6 at amino acid residue R315L. This mutation was also identified in the unaffected mother. In family 2, which consisted of one affected infant, a T‐to‐G transversion in exon 8 resulted in a change of phenylalanine to valine, F400V, and a C‐to‐T transition in exon 4 resulted in a change of proline to leucine, P248L. In this family, the mutation F400V was found in the unaffected father, and the mutation P248L was identified in the unaffected mother. These findings extend the growing body of literature documenting mutations in the TGM1 gene as the molecular basis of certain cases of lamellar ichthyosis.