bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns of cell death: the significance of apoptosis for dermatology
Authors: Paus Rald , Rosenbach Thomas , Haas Norbert , Czarnetzki Beate M.
Published: April 2006

Abstract Development, function, remodelling, and senescence of multicellular organisms depend on the coordinated occurrence of physiological, actively induced cell death in two major patterns: terminal differentiation and programmed cell death (apoptosis). Apoptosis is a highly selective form of “cell suicide” with characteristic morphological and biochemical features: chromatin condensation, formation of apoptotic bodies, and DNA fragmentation by activation of endonucleases. Here, we outline the current understanding of apoptosis and its subtypes, discuss their biological functions, and delineate why apoptosis is relevant to the skin and its diseases. We distinguish apoptosis from necrosis, and discuss the regulation of apoptosis by selected genes, hormones, growth factors and cytokines. The epidermis and the regressing hair follicle offer interesting models for studying the as yet ill‐understood biology of epithelial cell apoptosis. The selective manipulation of cell death programs may become part of the therapeutic arsenal of clinical dermatology.
Immunohistochemical study of purulent wounds treated with King crab collagenase
Authors: Sakharov I. Yu. , Shekhonin B. V. , Glyanzev S. P. , Litvin F. E.
Published: April 2006

Abstract Immunohistochemical study of tissues from purulent wounds in rats after treatment with the collagenase isolated from the King crab Paralithodes camtschitica was undertaken. The enzymotherapy resulted in a rapid and efficient removal of necrotic debris. It was accompanied by fibrin elimination from the wound bed and subsequent formation of new capillaries. Cellular fibronectin with ED‐A sequence was identified in the newly formed granulation tissue, which points to its active synthesis in situ. Polyclonal antibodies against two isozymes of the crab collagenolytic protease were obtained. By their use it was shown that, after application of the collagenase, both isozymes accumulated in fibrin deposits at the wound bed but did not penetrate adherent granulation tissue.
Effects of detergents on proliferation and metabolism of human keratinocytes
Authors: Bigliardi Paul L. , Herron Michael J. , Nelson Robert D. , Dahl Mark V.
Published: April 2006

Abstract Effects of low concentrations of detergents on cultured human foreskin keratinocytes were assessed in vitro. The viability and activity of keratinocytes were assessed by measuring reduction of a tetrazolium dye as an indicator of mitochondrial metabolism. The keratinocyte proliferative responses after incubation with detergents were assessed by a spectrophotometric assay employing crystal violet dye and a fluormetric assay determining total DNA content. Both the cationic detergent cetyltrimelhylammonium bromide [CTAB] and the anionic detergent sodium lauryl sulfate [SLS] showed toxic effects on keratinocytes at concentrations as low as 3 μg/mg, but SLS was less toxic. However, both SLS and CTAB activated keratinocytes at very low concentrations. Proliferalive activity and mitochondrial metabolism increased. Serum partially protected keratinocytes against toxic and stimulatory activities of both detergents. We suggest that detergents may directly damage keratinocytes and thereby produce irritant contact dermatitis, but activation of keratinocytes by low concentrations may also produce dermatitis, perhaps by causing keralinocvtes to release cytokines
The superoxide anion may mediate short‐ but not long‐term effects of ultraviolet radiation on melanogenesis
Authors: Tobin Derek , Thody Anthony J.
Published: April 2006

Abstract The present study was carried out to examine the role of reactive oxygen species in mediating the melanogenic effects of UVR. B16 mouse melanoma cells responded to a single dose of UVR by showing increases in their melanin content. Although there was a small increase in melanin at 48‐72 hours, which was associated with a rise in tyrosinase activity at 48 h, the greatest change occurred at 3 h and this was not associated with an increase in tyrosinase activity. This short‐term response, unlike the more delayed melanogenic response, was reduced by superoxide dismut‐ase (SOD). Xanthine oxidase (XO), which generates the superoxide anion (O2). also increased the melanin content of B16 melanoma cells with effects at 3 h and 48 h. As with UVR, the delayed response was accompanied by an increase in tyrosinase activity but no such association was evident at 3 h. In addition, the short‐term effect, like that seen with UVR, was reduced with SOD and to a lesser extent with catalase. In contrast to the effects found with XO, glucose oxidase, which generates hydrogen peroxide, had no effect on the melanin content or tyrosinase activity of the B16 cells. These results confirm previous observations that UVR is able to act directly on cells to bring about delayed increases in melanogenesis. They further demonstrate that UVR also stimulates melanogenesis through a more rapid action that is not associated with an activation of tyrosinase. This effect could be mediated by the O2 which, rather than activating tyrosinase, could act by serving as a substrate for the enzyme.
Effect of gamma‐interferon on IL‐1 alpha, beta and receptor antagonist production by normal human keratinocytes
Authors: Guéniche A. , Viac J. , Charveron M. , Schmitt D.
Published: April 2006

AbstractIn 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.
Ontogeny of nerves and neuropeptides in skin of rat: An immunocytochemical study
Authors: Karanth Suryanarayana S.
Published: April 2006

Abstract The sequence of maturation of nerves and appearance of neuropeptides was investigated in skin from fetal and neonatal rats by immunocytochemistry using antisera to protein gene product 9.5, substance P, calcitonin gene‐related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and neuropeptide Y (NPY). Immunoreactivity for PGP 9.5 appeared on fetal day 16 in face and nose, somewhat later (fetal day 19) in paws and tail. The sensory neuropeptides, CGRP/substance P (fetal day 19 and postnatal day 1, respectively) appeared earlier than the autonomic peptides VIP and NPY (postnatal day 7). Thus, the study shows that neuropeptides do not appear simultaneously with nerves and that the development is rostrocaudal.
TNFα‐induced activation of eosinophil oxidative metabolism and morphology ‐ Comparison with IL‐5*
Authors: Zeck‐Kapp Gabriele , Czech Wolfgang , Kapp Alexander
Published: April 2006

Abstract Human dermal mast cells are capable of releasing cytokines, particularly preformed TNFα, upon appropriate stimulation. Masl cell activation in vivo was shown to be associated with an influx and activation of inflammatory cells, initially PMN “polymorphonuclear neutrophilic granulocytes” then eosinophils. In order to learn more about the mechanisms by which TNFα is capable of activating eosinophils, in the present study the effect of TNFα on morphology and function of highly purified normal eosinophils “≥95%” was examined. As estimated by transmission and scanning electron microscopy, TNFα‐stimulated eosinophils appeared to be strictly adherent and flattened exhibiting a characteristic “hemispheric” shape. TNFα induced a dose‐dependent, long‐lasting production of reactive oxygen species as measured by lucigenin‐dependent chemiluminescence (CL). even at a concentration of 0.001 U/ml. The maximal response upon stimulation with TNFα, however, was significantly lower than optimal effects induced by IL‐5. TNFα‐induced responses were completely inhibited by cytochalasin B and staurosporin, and partially blocked by pertussis toxin. Separation of eosinophils by discontinuous density gradients revealed the existence of at least two hypodense eosinophil populations with a distinct susceptibility to stimulation with TNFα. Based on functional assay systems, in contrast to a significant extracellular, only a small intracellular H2O2: production was detected. Accordingly, H2O2 production, detected by an ultrastructural technique, was observed only on the outer surface of the plasma membrane in the contact zones in between adjacent cells. Extracellular as well as intracellular production of H2O2; was completely inhibited by cytochalasin B. TNFα‐induced activation of eosinophils is most probably mediated by binding to the 55 kD and the 75 kD TNF‐receptor since both receptor molecules could be detected by FACS analysis and immune electron microscopy using receptor‐specific antibodies. However, in contrast to its effect on eosinophil oxidative response, TNFα did not induce the release of significant concentrations of eosinophil cationic protein or eosinophil peroxidase in supernatants of cytokine‐stimulated eosinophils, as detected by functional as well as immunological assay systems. These results clearly indicate that TNFα represents a potent eosinophil‐activating cytokine which may be of relevance in the allergic inflammatory response.
Immunocytochemical detection of the carbohydrate antigen, Sialyl Lewisx, in normal human skin and during irritant contact dermatitis
Authors: Mikulowska Anna , Ohlsson Lennart , Boketoft Åke , Andersson Anders , Falck Bengt
Published: April 2006

Abstract Sialys Lewisx (SLex) is a ligand for the E‐selectin and the interaction of E‐selectin on the endothelium and SLex on T cells may be important for T‐cell migration into the skin. We investigated the expression of SLex on Langerhans cells (LC) in normal skin and on LC repopulating epidermis deprived of LC due to a preceding irritant contact dermatitis. SLex was visualized by fluorescence and light microscopic immunocytochemistry using the monoclonal antibody. CSLEX‐1. The results showed that about 40% of LC in normal epidermis express SLex. In the repopulation phase, most of the epidermal cells were CDla+/SLex+. We suggest that SLex is present on epidermal LC that have recently immigrated from the dermis.
Retinoic acid induces expression of PA‐FABP (psoriasis‐associated fatty acid‐binding protein) gene in human skin in vivo but not in cultured skin cells
Authors: Larsen Frederik Grønhøj , Voorhees John J. , Åström Anders
Published: April 2006

Abstract PA‐FABP (psoriasis‐associated fatty acid binding protein) is a new member of a group of low‐molecular‐weight proteins that are highly up regulated in psoriatic skin and that share similarity to fatty acid‐binding proteins. In this study we demonstrate that PA‐FABP transcripts are expressed in human skin in vivo and that topical application of 0.05% retinoic acid (RA) cream results in a rapid induction of PA‐FABP transcripts following treatment for 16 hours and persists at increasing levels after 48 and 96 h of RA treatment. The PA‐FABP mRNA response to RA was reduced by approximately 50% when patients concurrently were treated with RA and 0.025% clobelasol propionate (CLO) for 48 and 96 h, whereas treatment with CLO alone resulted in PA‐FABP transcript levels not significantly different from vehicle‐treated skin. When comparing the effects of a well‐known irritant, sodium lauryl sulfate (SLS), to those of RA and its vehicle, 0.05% RA cream but not 2% SLS in RA vehicle caused PA‐FABP mRNA induction after 16 h. SLS treatment of human skin for 96 h caused a slight increase in PA‐FABP transcripts, but markedly less than that observed in response to RA treatment. Incubation of cultured human keratinocytes or skin fibroblasts with RA for up to 48 h did not significantly induce PA‐FABP transcripts. Expression of PA‐FABP message in keratinocytes was observed to be induced by calcium and fetal calf serum (FCS), while tetra‐decanoyl phorbol acetate (TPA) caused little or no induction. Taken together, the marked inducibility of the PA‐FABP gene is compatible with the possibility that this gene might be important in RA‐mediated regulation of human skin growth and differentiation.
Nerve growth factor increases the mitogenicity of certain growth factors for cultured human keratinocytes: A comparison with epidermal growth factor
Authors: Wilkinson David I. , Theeuwes Margaret J. , Farber Eugene M.
Published: April 2006

Abstract Newborn foreskin and adult skin keratinocytes (KTs) were cultured in 24‐well plates using keratinocyte basal medium (KBM) either alone or supplemented with epidermal growth factor (EGF) or nerve growth factor (NGF), plus one of the following: insulin (INS), insulin‐like growth factors (IGF)‐l or ‐2, transforming growth factor alpha (TGFα), basic fibroblast growth factor (bFGF). Culture was maintained until one group of cells reached about 30,000 cells/well, when cells were stained with crystal violet and the extracted dye used to quantify cell numbers. In some cases, cells were subjected to the hexosaminidase assay for enumeration. In KBM alone, EGF, IGF‐1, IGF‐2 and TGFα were milogenic to newborn KTs. In addition, NGF increased the growth of adult KTs, possibly by mechanisms involving synergy with autocrine growth factors. EGF augmented the growth of newborn cells in the presence of each of the growth factors except TGFα, but adult cells exhibited only additive effects. In the presence of IGF‐1 or IGF‐2, NGF stimulated the growth of both newborn and adult cells by as much as 150% above purely additive increases in cell numbers. NGF amplifies the effects of most neurotrophic factors that are also KT mitogens and may therefore be significant in psoriatic lesions, where many of these factors are overex‐pressed, and in wound healing, in promoting KT growth.
Expression of murine VCAM‐1 in vitro and in different models of inflammation in vivo: correlation with immigration of monocytes
Authors: Henseleit U. , Steinbrink K. , Sunderkötter C. , Goebeler M. , Roth J. , Sorg C.
Published: April 2006

Abstract VCAM‐1 (vascular cell adhesion molecule‐1) is a cytokine‐in‐ducible adhesion molecule which is known to mediate adhesion of mononuclear cells to endothelial cells in vitro via binding to the integrin VLA‐4 (very late antigen‐4). To further elucidate the role and regulation of VCAM‐1 in vivo, we compared in vitro and in vivo expression of VCAM‐1 in response to cytokines and investigated immunohistochemically the expression of VCAM‐1 in three murine models of experimental inflammation. These models differed with regard to the pathogenetic mechanism and the subsequent infiltrate: allergic contact dermatitis (ACD) to DNFB as a T cell‐controlled, DTH type of inflammation, cutaneous infection with Leishmania major as a chronic granulomatous inflammation and the cauterized cornea as a model for acute inflammation. VCAM‐1 was found to be markedly enhanced on vascular endothelia in all types of inflammation and after subcutaneous administration of LPS and TNF‐a. Administration of IL‐4, however, failed to induce VCAM‐1 both in vivo and in vitro. The increased VCAM‐1 expression in the inflammatory models correlated with the appearance of infiltrating monocytes/ macrophages. A concomitant influx of CD4‐positive/CD8‐positive lymphocytes was only observed in ACD and Leishmaniasis.
Enhanced expression of IL‐8 in normal human keratinocytes and human keratinocyte cell line HaCaT in vitro after stimulation with contact sensitizers., tolerogens and irritants
Authors: Mohamadzadeh Mansour , Miiller Markus , Hultsch Thomas , Enk Alexander , Saloga Joachim , Knop Jürgen
Published: April 2006

Abstract To investigate the interleukin‐8 production of keratinocytes after stimulation in vitro we have used various agents: (i) contact sensi‐tizer (2,4‐dinitrofiuorobenzene, 3‐n‐penladecylcatechol); (ii) tolerogen (5‐methyl‐3‐n‐pentadecylcatechol); (iii) irritant (sodium lauryl sulfate). Interleukin‐8 gene expression was assessed by northern blot hybridization of the total cytoplasmic RNA extracted from subconfluent normal human keratinocyte cultures and the keratinocyte cell line HaCaT using a radiolabeled DNA probe specific for human interleukin‐8. Intcrleukin‐8 gene expression was markedly increased upon in vitro stimulation after 1‐6 h with contact sensitizers, tolerogen and the irritant. In contrast, in‐terlcukin‐8 production was not detectable in unstimulatcd normal human keratinocytes or the HaCaT keratinocyte cell line. These results suggest that the induction and production of interleukin‐8 is a response to nonspecific stimuli and may play a critical role in the early response to immuno‐genic or inflammatory signals in man.
Keratin expression in discoid lupus erythematosus
Authors: de Berker D. , Dean D. , Leigh I. M. , Burge S.
Published: April 2006

Abstract 21 lesions from 16 patients with discoid lupus erythematosus (DLE) were examined immunohistologically using monoclonal antibodies to keratins (K). Markers of basal epithelial cells (the keratin conformation specific basal markers LH6 and LH8), differentiating keralino‐cytes (K1 and K10), hyperproliferating keratinocytes (K16) and panepidermal keratin (K14), were used. A monoclonal antibody to type VII collagen was used as a guide to the stale of the basement membrane zone (BMZ). Keratin distribution in DLE differed from controls. Suprabasal cells were labelled by LH6 in 95% of specimens (19/20) and LH8 in 79% (15/19) in contrast to the basal distribution in normal skin. Reduction of suprabasal LL017 (K1) expression was seen in 59% (10/17) of lesions. An increase of LL025 (K16) expression was seen in 33% (5/15) of specimens. Where LL025 (K16) expression was increased, LL017 (K1) expression was reduced in 80% (4/5). Dermal colloid bodies expressed both basal and suprabasal keratins and were present at sites of maximal basement membrane disruption. These findings are consistent with a model of DLE in which there is an increase in the proliferative basal compartment. This compartment and the associated BMZ suffer fragmentation and loss of colloid bodies to the dermis which express a range of keratins not uniformly associated with basal keratinocytes.
tPA of human keratinocytes: contribution to cell surface‐associated plasminogen activation and upregulation by retinoic acid
Authors: Buessecker Frank , Reinartz Jcannette , Kramer Michael D.
Published: April 2006

Abstract We tested distinct variants of a human kerationocytc line (HaCaT) for the expression of tissue‐type plasminogen activator (tPA)‐specific mRNA. as well as cell surface‐associated and secreted tPA. Cells of early passages (passage no. 22) only expressed urokinase plasminogen activator (uPA)‐ bul not tPA‐specific mRNA. Cells after prolonged culture (passage no. 44) expressed uPA‐ and tPA‐specific mRNA, bul did not release tPA in the extracellular space and did nol display surface‐associated IPA. HaCaT cells transformed with the c‐Ha‐ras oncogene (HaCaTras) showed both secreted and surface‐associated tPA antigen. The secreted and the surface‐associated plasminogen activator (PA)‐activity of HaCaTras cells were in part inhibitable by anticatalytic anti‐tPA antibodies, thus indicating thai tPA contributes to extracellular and surface‐associated plasminogen activation. Finally, we demonstrate that tPA secretion of HaCaT 44 cells can be induced by retinoic acid, most likely via interaction of retinoic acid with nuclear‐associated retinoic acid‐receptor(s).
Neurochemical markers in human cutaneous Merkel cells
Authors: Fantini Fabrizio , Johansson Olle
Published: April 2006

Abstract Merkel cells (MCs) are specialized sensory cells widely distributed in the epithclia of vertebrates. A variable immunohistochemical pattern of neuronal and neurotransmitter markers has been demonstrated in MCs of several species including man. In the present study, we investigated the expression of neurochemical markers in a selected population of human cutaneous MCs by immunofluorescence. The structural neural proteins protein gene product 9.5 and neuron‐specific enolase were found to be the most reliable markers for MC identification. Moreover, neurofil‐ament immunoreactivity was shown in a small subset of epidermal MCs. Among the neurotransmitter markers, evidence for expression of calcitonin gene‐related peptide, vasoactive intestinal polypeptide, peptide histidine isoleucine amide, neuropeptide Y, neurokinin A, galanin, substance P, som‐atostatin and phenylethanolamine N‐methyltransferase was found. These immunoreactivities were highly variable as far as number of positive cells and staining intensity were concerned. The results indicate that a complex and heterogenous immunophenotype can be expressed even within a homogeneous population of human MCs.
T lymphocyte chemotaxis and skin diseases
Authors: Jinquan Tan , Thestrup‐Pedersen Kristian
Published: April 2006

Abstract Recent advances in our understanding of the mechanisms of T lymphocyte motility and chemotaxis, particularly in aspects of lymphocyte‐endothelial adhesion, transendothelial cell migration, and T‐lymphocyte response to chemotactic gradients have contributed to our knowledge of how T lymphocytes accumulate during the initiation, the development and the control of inflammatory skin responses. In this review, we will summarize the present situation of studies on T lymphocyte adhesion and chemotaxis. The 3 major steps in T lymphocyte chemotaxis, e.g., recognition of extracellular chemotactic gradients, transduction into ap‐propriate intracellular signals, and generation of motion, will be out‐lined. Skin‐homing T lymphocytes, chemokines and other chemoattractants will also be discussed in relation to skin diseases.
Low N‐acetylating capacity in patients with Stevens‐Johnson syndrome and toxic epidermal necrolysis*
Authors: Dietrich A. , Kawakubo Y. , Rzany B. , Mockenhaupt M. , Simon J. C. , Schöpf E.
Published: April 2006

Abstract Low constitutive N‐acetylating capacity has been implicated as a predisposing factor for the development of adverse reactions to certain drugs. This prompted us to investigate whether the N‐acetylating capacity of patients with serious cutaneous adverse reactions, i.e., Stevens‐Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) differed from that of healthy control subjects. N‐acctylating activity was measured in hair root cells by preparing a homogenate from freshly extracted hair roots and assessing acetyl‐CoA‐dependent N‐acetylation by RP‐HPLC using 2‐aminofluorene as a substrate. Samples were obtained from hospitalized patients suffering from acute SJS and TEN or from healthy controls. All patients with SJS and TEN were found to have a low N‐acetylating capacity (0.85 nmol/mg/min compared to 2.21 nmol/mg/min in controls, p<0.05). Based on these findings, a low constitutive N‐acetylating capacity may be one of the predisposing factors for the development of serious cutaneous adverse reactions to drugs that require N‐acetylation in these patients.
Gene rearrangement in positive patch tests
Authors: Wolff‐Sneedorff A. , Thomsen K. , Secher L. , Vejlsgaard G. Lange
Published: April 2006

Abstract Lymphoproliferative disorders are usually characterized by lymphoid infiltrates that demonstrate clonality in contrast to inflammatory or reactive infiltrates of the skin that are polyclonal without detectable monoclonal populations of T‐cells. Probably the southern blot analysis of TCR gene rearrangement can help to delineate the reactive from the malignant processes. In this study, we applied the technique on benign reactive processes in the skin. We examined biopsies from positive patch tests from patients with a delayed hypersensitivity reaction. We found the same gene rearrangement configuration in 11 of 17 patients with positive patch tests. The extra band revealed in these cases was situated in the EcoRl digested DNA lane at the 8.0 Kb, between the 2 germline bands at the 1 1 Kb and the 4 Kb respectively. This observation was not correlated to the degree of the inflammatory response or to the specific hapten induced reaction. This pattern was not found in any of 107 patients with malignant diagnoses, but also in six of 43 patients with benign diseases. The clinical implication may suggest the presence or development of clonality in benign inflammatory disorders.
Low ICAM‐1 expression in the epidermis of depigmenting C57BL/6J‐mivit/mivit mice: A possible cause of muted contact sensitization
Authors: Nordlund James J. , Csato Miklos , Babcock George , Takei Fumio
Published: April 2006

Abstract The depigmenting C57BL/6J‐mivit/mivit) (mivit/mivit) mouse, a congenic mutant of the C57BL/6 strain, exhibits an isolated, single immune deficiency. It is unable to mount a normal immune/inflammatory response upon epicutaneous application of DNFB or TNCB, although it does respond normally to oxazalone. The present investigtions have been carried out to further study this deficiency. In vivo, C57BL/6 mice could be sensitized by the epicutaneous application of the hapten TNCB, the subcutaneous injection of haplen(TNBS)‐conjugated C57BL/6, and hapten conjugated mivit/mivit epidermal cells. In the mivit/mivit mice, however, only subcutaneous injection of haptcnizcd C57BL/6 epidermal cells caused an immune response. The response of these mivit/mivit mice could be documented only by adoptive transfer of splenic lymphocytes into naive C57BL/6 animals which then reacted to challenge doses of TNCB. These observations suggest that mivit/mivit epidermal cells can process and present and mivit/mivit T lymphocytes can react to the antigen. We postulated the presence of a deficient in vivo interaction between epidermal cells and T lymphocytes in the mivit/mivit mice. ICAM‐I is an important adhesion signal regulating epidermal cell/T‐lymphocyte interaction. Us expression in mivit/mivit mice was studied using YN1/1 antibody against MALA‐2, the murine counterpart of human ICAM‐1. In contrast to C57BL/6 animals, the mivit/mivit epidermis essentially did not stain with the antibody after hapten challenge. In vitro after stimulation with TPA or IFN‐γ, the mivit/mivit epidermal cells expressed significantly lesser amounts of ICAM‐1 than the C57BL/6 epidermal cells. Lower expression of ICAM‐1 by mivit mivit/mivitsol;mivit epidermal cells has also been demonstrated both by direct staining and by flow cytomelry. The binding of lymphocytes to mivit/mivit epidermal monolayers, which were stimulated to express ICAM‐1 by IFN‐y, was decreased compared to that of C57BL/6 epidermal cells. We conclude that the muted contact sensiliza‐tion response detected in vivo in the mivit/mivit mice at least partly results from lower expression of ICAM‐1 and thus defective epidermal ccll/T‐lymphocyte interaction.
Interferon‐γ downregulates epidermal growth factor receptors on human melanoma cells
Authors: Worm Margitta , Makki Amira , Dippel Edgar , Czarnetzki Beate M. , Schadendorf Dirk
Published: April 2006

Abstract Unregulated expression of epidermal growth factor receptor (EGF‐R) is a common event in neoplastic transformation and has been shown to be associated with melanocytic tumor progression. Modulation of such a receptor by pharmacological agents could therefore be of clinical interest. We have studied EGF‐R expression, its response to epidermal growth factor (EOF) and modulation effects by interferon gamma (IFNγ) on human melanoma cells. Addition of EOF, anti‐EGF and anti‐EGF‐R antibodies had no effect on proliferation of six melanoma cell lines tested. We report in this communication that EGF‐R expression on human melanoma cells can be modulated by IFNγ. In the melanoma cell lines treated with IFNγ. proliferative behavior was not affected; however, we demonstrate a downregulation of EGF‐R expression on the protein level, by immunohistochemistry and flow cytometric analysis, and an accumulation of EGF‐R mRNA by Northern blot analysis. The results suggest that IFNγ downregulates EGF‐R expression at a posttranscriptional level on human melanoma cells. This EGF/EGF‐R interaction and its modulation by IFNγ on human melanoma cells needs to be further clarified regarding its in vivo significance for the treatment and prognosis of malignant melanoma.
PUVA suppresses the expression of cell adhesion molecules of lymphocytes
Authors: Urano Kazushi , Matsuyama Takashi , Urano Rie , Matsuo Iautsuro , Habu Sonoko
Published: April 2006

Abstract To determine the therapeutic mechanism of PUVA in psoriasis vulgaris, the effects of PUVA on activated T lymphocytes were investigated in vitro. Peripheral blood mononuclear cells (PBMC) obtained from healthy volunteers were activated with Con A stimulation (Con A blasts). Both untreated PBMC and Con A blasts were irradiated with UVA light in the presence of 8‐methoxypsoralen (8‐MOP). The expressions of CD4, CDS, VLA‐4 and LFA‐1 of PBMC and Con A blasts were stained with each monoclonal antibody and the intensity of fluorescence was analyzed by FACScan. PUVA‐treated PBMC showed decreased response to both Con A and PHA stimulation. PUVA treatment also suppressed the IL‐2 production of Con A blasts and IL‐2 response of PBMC with increasing UVA fluence. The expressions of LFA‐I, VLA‐4, CD4, CDS and CD25 (IL‐2R) molecules were decreased in PUVA‐treated Con A blasts. Con A blasts were more sensitive than untreated PBMC to PUVA treatment. These results suggest that the therapeutic effects of PUVA on psoriasis vulgaris can be induced by suppression of the expression of cell surface molecules of activated T lymphocytes.
Effect of parent genetic background on latency and antigenicity of UV‐induced tumors originating in F1 hybrids
Authors: Kitajima Toshiyuki , Iwashiro Michihiro , Kuribayashi Kagcmasa , Imamura Sadao
Published: April 2006

Abstract Wide variations in susceptibility to skin tumor development by chronic ultraviolet light (UV) exposure and antigenicity of induced tumors which is estimated by tumor rejection in syngeneic recipients have been recognized among various murine strains. To examine the effect of parent genetic background on latency and antigenicity of UV‐induced tumors originating in F1 hybrids, we induced skin tumors in three mouse strains: BALB/c, C57BL/6, (B6), and C3H/HeMs (C3H/He), and their F1, hybrids: (BALB/c×C3H/He)F1, (CC3F1), (BALB/c×B6)F1, (CB6F1) and (C3H/He×B6)F1, (C3B6F1) by exposing mice to UV radiation (0.44 mW/ cm2 for 1 h) three times a week, and analyzed whether the UV‐induccd tumors originating in F1 hybrids possess the similar property in latency or antigenicity as seen in the UV‐induced tumors derived from the parent strains. The latency of tumor induction by chronic UV exposure in C3H/He, BALB/c and their F1, hybrid CC3F1, was relatively short whereas that of B6 was relatively long, and that of F1, hybrids with B6 (CB6F, and C3B6F1) was intermediate. On the other hand, the low antigenicity as progressive growth behavior of UV‐induced tumors in syngeneic recipients was observed not only in tumors derived from C3H/He but also in those from F, hybrids with C3H/He (C3B6F1, and CC3F1) whereas most tumors derived from B6, BALB/c and their F1 hybrid CC3F1 were highly antigenic as to be rejected in syngeneic recipients. These findings suggest that the parent genetic quality regulating the susceptibility to tumor induction by chronic UV exposure is co‐dominantly inherited into F1 hybrids. On the other hand, that providing the progressive growth behavior of induced tumors appears to be a dominant effect.
Synthesis and degradation of connective tissue macromolecules in pachydermoperiostosis (PDF): evidence for altered processing of plasminogen activator inhibitor‐1 (PAI‐1)
Authors: Oikarinen Aarne , Kylmaniemi IVIceri , Palatsi Riitta , Keski‐Oja Jorma
Published: April 2006

Abstract Pachydermoperiostosis (POP) is a hereditary disease with hy‐perostosis, clubbing of fingers, coarse skin and thickening of bones. Previous studies have disclosed some abnormality in the connective tissue in these patients. The purpose of the present study was to investigate connective tissue pathology in one family with PDP using libroblasl cultures. Fibroblastic cells were established from both the affected and healthy looking skin of 2 patients with PDP, and the expression of types I and III collagen, 92 kDa and 72 kDa gelatinases, metalloproteinase inhibitor (TIMP‐1), human retinoic acid receptor and transforming growth factor β (TGFβ) was analyzed. The modulation of glycoprolein synthesis, and of plasminogen activators and their inhibitors by TGFβin vitro were also studied. The results indicated that collagen genes and gelatinases were similarly expressed in PDP and control cells, as well as the human retinoic acid receptor. TGF‐β stimulated, both in PDP cells and normal cells, the synthesis of fibroneclin, procollagen and plasminogen activator inhibitor‐1 (PAI‐1), but qualitative differences could not be found. Proteolytically processed forms of PAI‐1 were detected in PDP cell lines.
Proto‐oncogenes and oncogenes in epidermal neoplasia
Authors: Simon M. M. , Sliutz G. , Luger T. A.
Published: April 2006

Abstract This review briefly will focus on the role of selected proto‐onco‐genes and their activated forms during the regulation of cell proliferation, cell death and tumor formation in the epidermis. In addition, the multiple and complex functions of these proteins in normal as well as transformed cells will be discussed.
Incorporation of 15‐hydroxyeicosatrienoic acid in specific phospholipids of cultured human keratinocytes and psoriatic plaques
Authors: Heitmann Jette , Iversen Lars , Kragballe Knud , Ziboh Vincent A.
Published: April 2006

Abstract 15‐hydroxyeicosatrienoic acid, 15‐HETrE, the 15‐lipoxygenase product of dihomogammalinolenic acid (DGLA), can inhibit the biosynthesis of the proinflammatory eicosanoids leukotriene B4 (LTB4) and 12‐hydroxyeicosatctraenoic acid (12‐HETE). The purpose of the present study was to investigate the incorporation of [I4C] 15‐HETrE in specific membrane phospholipids of cultured human keratinocytes in vitro. [I4C] 15‐HETrE was rapidly incorporated into keratinocytes. When a plateau was reached after 3 hours, 15% of the added radioactivity was incorporated into lipids; 96.5% into phospholipids (PL) and 3.5%. into neutral lipids (NL). Within the phospholipid classes, [I4C]15‐HETrE showed selectivity for incorporation into phosphatidylinositol (PI). The mean proportion of [I4C] 15‐HETrE in the PI, phosphatidylcholin (PC) and phosphatidyle‐thanolamin (PE) was 83.2%, 8.5% and 8.3%, respectively. We then investigated the incorporation of 15‐HETrE in epidermal phospholipids of psoriatic skin intralesionally injected with 15‐HETrE. Four patients took part in the study. In each patient four identical plaques were injected with 0.65 ml of 2.0 µM, 6.2 µM, 18.6 µM of 15‐HETrE (0.4 µg, 1, 2 µg and 3.6 µg respectively) or 0.65 ml of 0.88% NaCl twice a week. After 3 wk keratome biopsies were obtained from the treated plaques. Phospholipids extracted from the skin biopsies were separated into major classes by two‐dimensional thin layer chromatography. 15‐HETrE was then released from specific phospholipids after treatment with phospholipase A2 and identified by reverse phase and straight phase high preformance liquid chromatography. There was a dose‐dependent incorporation of 15‐HETrE into the specific phospholipids PI and PC. When expressed as ng 15‐HETrE/ug phospholipid phosphate, 15‐HETrE accumulated preferent‐ically in PI. After injection of the highest 15‐HETrE concentration, the mean amount of 15‐HETrE estcrified in PI and PC was 81.9 ng/µg PI phosphate and 19.4 ng/µg PC phosphate, respectively. This incorporation of 15‐HETrE incorporated into epidermal PLs was not accompanied by a clinical change of the treated psoriatic plaques. It remains to be determined whether higher 15‐HETrE incorporated might induce clinical improvement of psoriasis.
Effect of azelaic acid on melanoma cells in culture
Authors: Lemic‐Stojcevic L. , Nias A. H. W. , Breathnach A. S.
Published: April 2006

Abstract Using a clonogenic assay in vitro, it has been shown that exposure to azelaic acid “1‐100 mM” for 24 hours has a dose‐dependent effect on the survival of the colony‐forming ability of murine “B16” and human “HMB2, and SK23” melanoma cells as compared with a non‐melanotic non‐tumoral Chinese hamster cell line “CHO”. Both human cell lines were more sensitive to the diacid than the murine cells, and the HMB2 cells were more sensitive than the SK23 cells. These differences may be partly correlated with differences in pigmentation and doubling times between the three melanoma cell lines. The two human lines were more pigmented than the B16, and the SK23 more than the HMB2; the human lines had a longer doubling time than the others.
Histaminergic nerves demonstrated in the skin. A new direct mode of neurogenic inflammation?
Authors: Johansson Olle , Virtanen Markku , Hilliges Marita
Published: April 2006

Abstract An intradermal administration of histamine into human skin results in a local erythema, edema and often also the sensations of itch and/or pain. These effects have classically been attributed to the presence of histamine‐containing mast cells. However, in the present investigation, we report the observation of histamine‐immunoreactive nerves in the skin of Sprague‐Dawley rats using a new and highly sensitive immunohistochemical approach. These data suggest a more direct route of cutaneous histamine effects, mediated exclusively by the peripheral nervous system. The findings could also give a new basis for explaining histamine‐related issues, such as itch.
Contact sensitizers modulate mechanisms of receptor‐mediated endocytosis but not fluid‐phase endocytosis in murine epidermal Langerhans cells
Authors: Becker Detlef , Lempertz Uwe , Enk Alexander , Saloga Joachim , Knop Jürgen
Published: April 2006

Abstract In order to define the influence of contact allergens on the fluid‐phase endocytosis (FPE) of soluble molecules of murine epidermal Langerhans cells (LC), we studied the internalization of FITC‐labeled bovine serum albumin (FITC‐BSA), TRITC‐labeled dextrane (TRITC‐DEX) as well as horseradish peroxidase by LC. A 3‐parameter flow‐cytometric technique was performed for quantification of internalized FITC‐BSA in LC using quantum red‐labeled reagents for detection of la‐antigen expression by LC and propidium iodide for exclusion of dead cells from analysis. A temperature‐dependent rapid accumulation of FITC‐BSA was noticed in time‐course studies reaching a plateau between 1 and 2 h of in vitro culture at 37°C. The quantity of FPE under stimulation with phorbol 12‐myristate 13‐acetate (PMA), concanavalin A (Con A), sta‐phylococcal enterotoxin B (SEB) and contact sensitizers (DNFB, Kathon CG, K2Cr2O7) as well as the irritant SLS was determined. Treatment of LC with PMA and Con A resulted in a significant increase of total FITC‐BSA uptake. The contact sensitizers as well as SEB and SLS failed to mediate augmented fluid‐phase endocytosis. By use of the pH‐insensitive soluble marker, TRITC‐DEX and a microscope photometer for evaluation these findings could be confirmed. This excluded any artificial influence of differences in pH values in endocytotic compartments which might have influenced the fluorescence intensity of the pH‐sensitive fluoro‐chrome FITC. For qualitative analysis of FPE, the intracellular distribution of internalized horseradish peroxidase in LC was studied. An aggregated pattern became apparent in untreated LC and did not change under stimulation with any of the substances used. This was in sharp contrast to a modulation of receptor‐mediated endocytosis of antibody‐crosslinked MHC class II molecules under the influence of contact sensitizers, and suggested that haplen‐mediated endocytotic activation of LC was restricted to this mechanism of inlernalization.
Porphyrin concentrations in various human tissues
Authors: Goerz Günter , Link‐Mannhardt Andrea , Bolsen Klaus , Zumdick Matthias , Fritsch Clemens , Schürer Nanna Y.
Published: April 2006

AbstractWe measured the concentrations of total porphyrins and their metabolites (uro‐, hepta‐, hexa‐, penta‐, copro‐ and protoporphyrin) in various human tissues: liver, erythrocytes, skin, adipose tissue, and mammary gland. The porphyrin concentrations varied within minor limits, e.g., 3.1 ±2.3 nmol porphyrins/g liver and 0.50±0.10 nmol/g erythrocytes. No significant differences were detectable in other tissues in comparison with liver. In all tissues, the predominant metabolite was protoporphyrin, followed by coproporphyrin, whereas only low concentrations of higher carboxylatcd porphyrins such as uroporphyrin were detectable. It is concluded that porphyrin metabolism and its regulation is similar in all human tissues, perhaps with some small differences in the erythrocytes.
Direct and indirect receptor‐independent G‐protein activation by cationic‐amphiphilic substances. Studies with mast cells, HL‐60 human leukemic cells and purified G‐proteins
Authors: Klinker Jan F. , Hageluken Astrid , Griinbaum Lore , Seifert Roland
Published: April 2006

Abstract Studies from several laboratories have revealed that structurally diverse substances including the wasp venom, mastoparan (MP), activate purified regulatory heterotrimeric guanine nucleotidc‐binding proteins (G‐proteins) in a receptor‐independent manner, presumably by mimicking the effects of heptahelical receptors. Mast cells and differentiated HL‐60 human leukemic cells are useful model systems for the analysis of receptor‐independent G‐protein activation. We compared the effects of 2‐phenylhistamines which are cationic‐amphiphilic, too, and of MP on G‐protein activation in dibutyryl cAMP‐differentiated HL‐60 cells and in the rat basophilic leukemia cell line, RBL 2H3. In HL‐60 cells, 2‐phenylhistamines show stimulatory effects which resemble those of formyl peptide receptor agonists but which cannot be attributed to agonism at classical receptors. 2‐phenylhistamines do not, however, activate RBL 2H3 cells and various other myeloid cell types, pointing to cell type‐specificity of receptor‐independent G‐protein activation. In HL‐60 cells, MP shows effects on G‐protein activation which differ substantially from those of formyl peptides. In RBL 2H3 membranes, MP shows similar effects on G‐prolein activation as in HL‐60 membranes. We develop a model according to which receptor‐independent G‐protein activation can be subdivided into direct and indirect receptor‐independent G‐protein activation. In case of the former mechanism, substances like 2‐phenylhislamines interact with G‐protein α‐subunits and in case of the latter mechanism, substances like MP interact with nucleoside diphosphate kinase which catalyzes the formation of GTP. This newly formed GTP is then transferred to, and cleaved by, G‐protein a‐subunits. NDPK is a novel target for the design of drugs which interfere with G‐protein‐mcdiated signal transduction at a post‐receptor level and may modulate the function of various cell types including mast cells.
Mouse mast cell cytokine production: rôle in cutaneous inflammatory and immunological responses
Authors: Galli Stephen J. , Wershil Barry K.
Published: April 2006

Abstract The rôle of mast cells in cutaneous physiology and pathology has long been a subject of intense speculation and great clinical interest. In this brief review, which is focused primarily on murine systems, we outline certain important aspects of the biology of the mast cell, including their ability to produce a variety of cytokines, describe the development of a model system (the “mast cell knock‐in mouse”) for studying the roles of cutaneous mast cells in biological responses in vivo, and illustrate a few examples of how this approach has been used to investigate the contributions of mast cells and their cytokines to cutaneous inflammatory or immune responses.
Chemokines and the allergic response
Authors: Kaplan Allen P. , Kuna Piotr , Reddigari Sesha R.
Published: April 2006

Abstract The β subfamily of chemokines contains‐cytokine‐like factors which are chemotactic for human basophils and eosinophils. They also stimulate these cells to secrete pro‐inflammatory substances such as histamine or eosinophil cationic protein. MCAF/MCP‐1, MCP‐2, MCP‐3, RANTES and MIP‐lα all attract and stimulate basophils; MCP‐I and MCP‐3 are the most potent. RANTES, MCP‐3 and to a lesser degree MIP‐Ia are chemotactic factors and activators of eosinophils. Cytokines such as IL3, IL5 and GM CSF can augment the responses of these cells to the various chemokines and function as primers. These substances may have particular importance as mediators of allergic inflammation, particularly the late phase component of the response.
Pharmacological modulation of IL‐6 and IL‐8 secretion by the H1‐antagonist decarboethoxy‐loratadine and dexamethasone by human mast and basophilic cell lines
Authors: Lippert U. , Krüger‐Krasagakes S. , Möller A. , Kiessling U. , Czarnetzki B. M.
Published: April 2006

Abstract Mast cells and basophils are central effector cells of allergic reactions and are involved in inflammatory diseases. These cell types produce an array of mediators including a broad spectrum of cytokines. In order to examine whether antiallergic drugs modulate the release of these mediators, we have investigated the influence of dexamethasone and decarboethoxy‐loratadine (DEL), the active metabolite of the H1‐blocking agent loratadine, on the release of IL‐6 and IL‐8 by the human mast cell line HMC‐1 and the human basophilic cell line KU812 by ELISA. Dexamethasone (10−6‐10−11 M) or Del (10−5‐10−14 M) were added to the cells either 1 h prior to or simultaneously with PMA and Ca‐ionophore A23187. When preincubated with the cells, DEL dose‐dependently suppressed IL‐6 release by up to 40% and IL‐8 release by up to 50%. Dexamethasone potently suppressed secretion of both cytokines if simultaneously added to the cells with the stimuli by up to 60% and after preincubalion by up to 80%. Since both antihistamines and glucocorticoids are used for treatment of allergic diseases, the findings reported here indicate that these drugs may modulate allergic reactions via inhibition of cytokine release from mast cells and basophils.
Cytokine treatment of mast‐cell‐mediated skin diseases
Authors: Luger T. A.
Published: April 2006

Abstract Cytokines released by mast cells as well as their effects on mast cell functions appear to be of major importance in the pathogenesis of mast cell mediated skin diseases. In addition, the identification of some key mediators which were found to play a crucial in vivo rôle in certain disease states may allow the development of new therapeutie strategies using cytokines or cytokine antagonists for the treatment of inflammatory skin diseases. So far, encouraging results have been obtained when diseases with mast cell involvement such as atopic eczema or mastocytosis have been treated with different IFNs. Future trials using IFNs and other newly detected cytokines or their antagonists are required to establish effective therapy regimens.