Search PubMed⌕ Search

Biomedical subjects

E Christophers

Publications and source records attributed to E Christophers.

At least 91 records · Page 5Linked to original sources
PubMed1998

Delayed production of biologically active O-glycosylated forms of human eotaxin by tumor-necrosis-factor-alpha-stimulated dermal fibroblasts.

Since a number of inflammatory skin diseases are characterized by selective eosinophil infiltration preferentially in the dermis, we speculated that dermal fibroblasts might represent a potential cellular source of eosinophil-selective attractants. Cultivated dermal fibroblasts treated with tumor necrosis factor alpha secreted, not before day 3 of stimulation, eosinophil-specific chemotactic activity. Purification of this activity revealed a heparin-binding protein with an apparent molecular mass of 13 kDa in SDS/polyacrylamide gel electrophoresis. Peptide mapping with subsequent amino acid sequence analyses revealed it to be human eotaxin. Natural eotaxin preparations contain 50% N-terminally truncated forms missing two or three amino acids. It is O-glycosylated at Thr71, resulting in at least two sialylated O-glycosylated variants. Electrospray ionization mass spectrometric analyses revealed the natural eotaxin preparation to be heterogeneous with principal masses of 9033 Da and 9317 Da. Natural eotaxin stimulated eosinophil chemotaxis with identical potency and efficacy as recombinant human eotaxin. Neither neutrophils, monocytes or lymphocytes responded towards natural eotaxin preparations indicating that N-terminal truncation and O-glycosylation did not affect the cell-specificity of chemotactic activity. Treatment of eosinophils with natural eotaxin desensitizes chemotactic responses towards eotaxin, regulated an normal T-lymphocyte expressed and secreted (RANTES) and monocyte chemotactic protein 3 (MCP-3), whereas RANTES and MCP-3 were unable to desensitize natural eotaxin-dependent responses.

Amino Acid Sequence↗
PubMed1998

IL-4 induces eotaxin: a possible mechanism of selective eosinophil recruitment in helminth infection and atopy.

A common feature of some parasitic infections and allergic and atopic skin diseases is the involvement of Th2 lymphocytes and the dermal appearance of eosinophils (Eos). Because Th2 lymphocytes apparently do not release Eo attractants, we addressed the question of whether the Th2 cytokine IL-4 induces its production in dermal fibroblasts. We therefore stimulated fibroblasts with IL-4. HPLC investigation of supernatants revealed a single Eo chemotactic protein, which was purified to homogeneity giving a single 13-kDa band upon SDS-PAGE analyses. Peptide mapping with subsequent amino acid sequencing revealed an Eo-selective chemotaxin, which consists of a mixture of N-terminally truncated and O-glycosylated forms of the chemokine eotaxin. Other chemokines such as RANTES, MCP-3, MCP-4, or MIP-1alpha were not detected as Eo chemotaxins under these conditions. Using reverse transcriptase-PCR techniques, we found that IL-4 dose and time dependently induces eotaxin mRNA in dermal fibroblasts. Stimulation with IL-4 and TNF-alpha caused a 10- to 20-fold increase of the release of three biochemically different eotaxin forms, each consisting of a mixture of N-terminally truncated and O-glycosylated variants having the same backbone amino acid sequence but different specific activities. Our findings support the hypothesis that eosinophil recruitment seen in IL-4-mediated skin reactions, at least in part, may be due to Th2 cytokine-mediated induction of eotaxin in dermal fibroblasts.

Amino Acid Sequence↗
PubMed1998

Generalized atrophic benign epidermolysis bullosa in 2 siblings complicated by multiple squamous cell carcinomas.

BACKGROUND: Generalized atrophic benign epidermolysis bullosa is a form of junctional epidermolysis bullosa characterized by skin fragility; atrophic alopecia; sparse eyebrows, eyelashes, and axillary and pubic hair; dystrophic fingernails and toenails; and enamel defects in decidual and permanent teeth. Substantial progress was recently made elucidating the genetic defects underlying this disorder. In affected persons, pathogenetic mutations were identified in the genes encoding the beta 3 chain of laminin 5 (LAMB3) or the 180-kd bullous pemphigoid antigen (BPAG2/COL17A1). OBSERVATIONS: Two brothers, aged 39 and 32 years, had characteristic clinical features of generalized atrophic benign epidermolysis bullosa. By electron microscopy, dermoepidermal separation was seen at the level of the lamina lucida, establishing a diagnosis of junctional epidermolysis bullosa. Lesional and clinically unaffected skin showed basal keratinocytes with hypoplastic hemidesmosomes, possibly indicating a defect of hemidesmosomal or associated proteins. Both patients presented with multiple fungating tumors on atrophic and scarred skin on their lower legs; 2 tumors in the older sibling and 4 tumors in the younger sibling were diagnosed as well-differentiated squamous cell carcinomas. Tumor staging elicited no evidence of regional lymph node involvement or systemic disease. Treatment was by microscopically controlled surgery. All wounds were allowed to heal by secondary intention. In both patients, wound healing was markedly delayed and characterized by the formation of abundant granulation tissue and poor re-epithelialization. CONCLUSIONS: In the absence of other apparent risk factors for the development of squamous cell carcinomas, chronic wounding resulting from recurrent skin blistering probably provided an important prerequisite for tumor promotion in these patients. The 2 cases presented herein provide evidence that the development of malignant skin tumors in patients with epidermolysis bullosa is not confined to the dystrophic forms but also may occur in some variants of junctional epidermolysis bullosa, such as generalized atrophic benign epidermolysis bullosa.

Adult↗
PubMed1998

[Tinea caused by Trichophyton equinum].

We report on the first human infection with Trichophyton equinum in Germany, which was transmitted from an infected pony to a 12-year old girl. Trichophyton equinum was identified by its morphology, dependency on nicotinic acid, hair perforation, and enzyme production. A noteworthy new observation was the development of white pleomorphic tufts on the surface of thalli grown on potatoe-dextrose agar. The girl's tinea was non-inflammatory and responded promptly to topical treatment, whereas the pony's strongly inflammatory lesions persisted for months. In supernatants of cultures supplemented with different nutrients, enzyme patterns were measured for Trichophyton equinum that correspond to other species of dermatophytes more pathogenic for humans. Therefore, a lack of enzymes is apparently not the explanation for the rarity of human infections with Trichophyton equinum. More likely, predisposing factors of the host are necessary in combination with a close contact to infected horses. Treatment of infected humans appears to be no major problem.

Animals↗
PubMed1998

Linkage between atopy and the IgE high-affinity receptor gene at 11q13 in atopic dermatitis families.

Atopic dermatitis is a common skin disease frequently associated with allergic disorders such as allergic rhinitis and asthma. Controversial linkage findings between atopy and markers at chromosome 11q13 led us to search chromosome 11 for genes conferring susceptibility to atopic dermatitis and atopy. Twelve families were investigated using highly polymorphic markers and a powerful model-free linkage test. Two markers gave evidence for linkage, D11S903 (P = 0.02) and FCER1B (P = 0.005). A two-point lod-score analysis between these two markers revealed significant evidence for linkage (zmax = 4.02 at (theta = 0.0). In regard to model-dependent lod-score analyses between atopic disorders and FCER1B, two-point analysis gave a lod score of z = 0.78 whereas two-locus analysis using a recessive-dominant mode of inheritance displayed a significant lod score of z = 3.55. Only 2 of 12 families showed evidence for linkage using the latter oligogenic model. In conclusion, the results of our study map the FCER1B gene in close proximity to D11S903, support the finding of Cookson et al. implicating the IgE high-affinity receptor gene (FCER1B) at 11q13, and furthermore suggest an oligogenic mode of inheritance as well as heterogeneity in the genetic susceptibility to atopy and atopic dermatitis.

Adolescent↗
PubMed1998

Omega-3 fatty acid-based lipid infusion in patients with chronic plaque psoriasis: results of a double-blind, randomized, placebo-controlled, multicenter trial.

BACKGROUND: Profound changes in the metabolism of eicosanoids with increased concentrations of free arachidonic acid (AA) and its proinflammatory metabolites have been observed in psoriatic lesions. Free eicosapentaenoic acid (EPA) may compete with liberated AA and result in an antiinflammatory effect. OBJECTIVE: Our purpose was to assess the efficacy and safety of intravenously administered fish-oil-derived lipid emulsion on chronic plaque-type psoriasis. METHODS: A double-blind, randomized, parallel group study was performed in eight European centers. Eighty-three patients hospitalized for chronic plaque-type psoriasis with a severity score of at least 15 according to the Psoriasis Area and Severity Index (PASI) participated in a 14-day trial. They were randomly allocated to receive daily infusions with either a omega-3 fatty acid-based lipid emulsion (Omegavenous; 200 ml/day with 4.2 gm of both EPA and docosahexaenoic acid (DHA); 43 patients) or a conventional omega-6-lipid emulsion (Lipovenous; EPA+DHA < 0.1 gm/100 ml; 40 patients). The groups were well matched with respect to demographic data and psoriasis-specific medical history. Efficacy of therapy was evaluated by changes in PASI, in an overall assessment of psoriasis by the investigator, and a self-assessment by the patient. In one center neutrophil 4- versus 5-series leukotriene (LT) generation and platelet 2- versus 3- thromboxane generation were investigated and plasma-free fatty acids were determined. RESULTS: The total PASI score decreased by 11.2 +/- 9.8 in the omega-3 group and by 7.5 +/- 8.8 in the omega-6 group (p = 0.048). In addition, the omega-3 group was superior to the omega-6 group with respect to change in severity of psoriasis per body area, change in overall erythema, overall scaling and overall infiltration, as well as change in overall assessment by the investigator and self-assessment by the patient. Response (defined as decrease in total PASI of at least 50% between admission and last value) was seen in 16 of 43 patients (37%) receiving the omega-3 emulsion and 9 of 40 patients (23%) receiving omega-6 fatty acid-based lipid emulsion. No serious side effects were observed. Within the first few days of omega-3 lipid administration, but not in the omega-6 supplemented patients, a manifold increase in plasma-free EPA concentration, neutrophil leukotriene B5 and platelet thromboxane B3 generation occurred. CONCLUSION: Intravenous omega-3-fatty acid administration is effective in the treatment of chronic plaque-type psoriasis. This effect may be related to changes in inflammatory eicosanoid generation.

Adult↗
PubMed1998

Treatment of psoriasis with fumaric acid esters: results of a prospective multicentre study. German Multicentre Study.

Systemic treatment of psoriasis with fumaric acid esters (FAE) has been found effective by empirical means. In recent years clinical studies have confirmed the antipsoriatic activity of a defined mixture of different FAE. The aim of the present prospective multicentre study was to investigate further the efficacy and safety of FAE therapy in a large number of patients with severe psoriasis vulgaris. From 101 patients included in the study 70 completed the treatment period of 4 months. Discontinuation was due to adverse events in seven, lack of efficacy in two, and other reasons, such as non-attendance for scheduled visits, in 22 patients. Evaluation of overall efficacy showed a decrease in psoriasis area and severity index of 80% after 4 months of FAE therapy. Laboratory investigations revealed a slight overall decrease of lymphocytes during the treatment period which was more than 50% below baseline in 10 patients. During weeks 4 and 8 mean eosinophil counts were above the normal range. At the end of FAE therapy elevated eosinophil counts had returned to normal values. None of the patients showed changes in renal function parameters throughout the study. Adverse events were reported in 69% of the patients mainly consisting of gastrointestinal complaints (56%) and flushing (31%). In five patients gastrointestinal complaints and in two patients flushing led to withdrawal from the study. Taken together the results of this multicentre study showed in a large number of patients that systemic FAE treatment is effective in severe psoriasis vulgaris. Transient eosinophilia seems to be a characteristic feature of FAE therapy, while lymphocytopenia is usually mild. Adverse effects are dose-related and consist mainly of gastrointestinal complaints and flushing.

Adult↗
PubMed1998

The novel ascomycin derivative SDZ ASM 981 is effective for psoriasis when used topically under occlusion.

Topical SDZ ASM 981 has been found to be highly effective in preclinical models of T-cell-mediated skin disease. T cell activation is crucial in the pathogenesis of psoriasis. It has been hypothesized that SDZ ASM 981 may prove to be an effective treatment for chronic plaque psoriasis. Therefore, the study objective was to determine the efficacy, tolerability and safety of the new topical macrolactam, SDZ ASM 981, for chronic plaque psoriasis. Ten patients with chronic plaque-type psoriasis were treated with SDZ ASM 981 (0.3% and 1.0%), the corresponding ointment base (placebo) and open-labelled clobetasol-17-propionate ointment (0.05%) in a randomized, double-blind, within-subject comparison for 2 weeks using the microplaque assay. Evaluation was performed by daily determination of clinical scores for erythema and induration. The results of the study showed that, after 2 weeks of treatment, total scores described by 92% for clobetasol, by 82% for 1 SDZ ASM 981, by 63% for 0.3% SDZ ASM 981 and by 18% for the ointment base (placebo). No adverse drug effects were seen in any patient throughout the study. We conclude from our results that the new macrolactam SDZ ASM 981 (1%) is similar to clobetasol-17-propionate (0.05%) in plaque-type psoriasis when applied topically under occlusion for 2 weeks using the microplaque assay.

Administration, Topical↗
PubMed1998

The CXC receptor 2 is overexpressed in psoriatic epidermis.

The CXC chemokines interleukin-8 and GRO/melanoma growth-stimulatory activity (GRO-alpha) are potent activators of neutrophils and lymphocytes, but also stimulate growth and differentiation of nonhematopoietic cells like keratinocytes, fibroblasts, and melanocytes. High mRNA and protein levels have been detected in psoriatic epidermis. Chemokine activation of target cells is mediated by specific receptors and two CXC receptors have been described with similar affinity for interleukin-8 but different affinities for GRO-alpha. In this study, we examined the expression of both CXCR1 and CXCR2 in psoriatic tissue, identifying the target cells of chemokine activation in psoriasis. By immunohistochemistry and in situ hybridization, as confirmed by northern blot analysis and reverse transcriptase polymerase chain reaction, we could detect expression of the CXCR2 in suprabasal lesional psoriatic keratinocytes but not in healthy skin. The CXCR1 could not be localized in psoriatic keratinocytes with immunohistochemistry and in situ hybridization, but infiltrating cells in the dermal compartment expressed both types of receptors. These data suggest that in addition to neutrophil activation by both CXCR1 and CXCR2, activation of keratinocytes mediated by CXCR2 could contribute to the characteristic epidermal changes observed in psoriasis.

Antibodies, Monoclonal↗
PubMed1998

Linkage analysis of human leukocyte antigen (HLA) markers in familial psoriasis: strong disequilibrium effects provide evidence for a major determinant in the HLA-B/-C region.

Although psoriasis is strongly associated with certain human leukocyte antigens (HLAs), evidence for linkage to HLA markers has been limited. The objectives of this study were (1) to provide more definitive evidence for linkage of psoriasis to HLA markers in multiplex families; (2) to compare the major HLA risk alleles in these families with those determined by previous case-control studies; and (3) to localize the gene more precisely. By applying the transmission/disequilibrium test (TDT) and parametric linkage analysis, we found evidence for linkage of psoriasis to HLA-C, -B, -DR, and -DQ, with HLA-B and -C yielding the most-significant results. Linkage was detectable by parametric methods only when marker-trait disequilibrium was considered. Case-control association tests and the TDT identified alleles belonging to the EH57.1 ancestral haplotype as the major risk alleles in our sample. Among individuals carrying recombinant ancestral haplotypes involving EH57. 1, the class I markers were retained selectively among affecteds four times more often than among unaffecteds; among the few affected individuals carrying only the class II alleles from the ancestral haplotype, all but one also carried Cw6. These data show that familial and "sporadic" psoriasis share the same risk alleles. They also illustrate that substantial parametric linkage information can be extracted by accounting for linkage disequilibrium. Finally, they strongly suggest that a major susceptibility gene resides near HLA-C.

Adult↗
PubMed1998

Association of rare human papillomavirus types with genital premalignant and malignant lesions.

Due to the limited number of reports concerning their association with particular dysplastic and neoplastic lesions, the oncogenic potential of so-called rare or novel human papillomavirus (HPV) types is still unclear. Cytologic smears or biopsy specimens from 538 patients were analyzed for dysplastic or neoplastic lesions and HPV infection. The HPV detection and typing system utilized allowed identification of all mucosal HPVs amplifiable by L1 polymerase chain reaction. Considering only patients infected with a single HPV type (n = 329), rare or novel HPVs (HPV-59, HPV-61, HPV-62, HPV-66, HPV-70, HPV-73, MM4, MM7, MM8, CP6108, and CP8304) were detected in 28% of normal specimens (n = 46), none of condylomatous lesions (n = 44), 12% of low-grade squamous intraepithelial lesions (SILs) (n = 42), 8% of high-grade SILs (n = 142), and 4% of cervical cancers (n = 54). Prevalence and oncogenic potential of distinct rare HPV types seems to be higher than previously assumed.

Condylomata Acuminata↗
PubMed1997

Mapping of the gene encoding human beta-defensin-2 (DEFB2) to chromosome region 8p22-p23.1.

We recently reported the isolation of human beta-defensin-2 (hBD-2), a novel epithelia-derived peptide antibiotic belonging to the beta-defensin family. hBD-2 is expressed in skin and epithelia of the airway system, where it is believed to contribute to its antimicrobial defense. By fluorescence in situ hybridization using a hBD-2 genomic DNA probe and subsequent fluorescence R-banding, the hBD-2 gene (HGMW-approved symbol DEFB2) was assigned to human chromosome region 8p22-p23.1. PCR with a set of CEPH YAC clones spanning this chromosomal region revealed CEPH YACs 773G4, 920D12, and 820B4 to contain the hBD-2 gene. Relying on the preexisting physical maps of 8p22-p23.1, the hBD-2 gene was mapped in close proximity to D8S1993 (WI-9956) within the interval flanked by D8S552 and D8S1130 (CHLC.GATA25C10). The fact that all currently described genes encoding defensins map to chromosome 8p21-pter suggests that a gene cluster in this chromosomal region may play a major role in antimicrobial defense.

Blood Proteins↗
PubMed1997

Genomic organization, sequence, and transcriptional regulation of the human eotaxin gene.

Eotaxin is an eosinophil specific beta-chemokine assumed to be involved in eosinophilic inflammatory diseases such as atopic dermatitis, allergic rhinitis, asthma and parasitic infections. Its expression is stimulus- and cell-specific. We here describe the genomic organisation (3 exons of 132, 112 and 542 bp and 2 introns of 1211 and 378 bp) and sequence including 3 kb of DNA from the immediate 5' upstream region of the human eotaxin gene. Among the regulatory promoter elements potentially regulating eotaxin gene expression and/or mediating the effects of anti-inflammatory drugs we identified consensus sequences known to interact with nuclear factors like NF-IL6, AP-1, a NF-kappa-B like consensus sequence and gamma-interferon- as well as glucocorticoid response elements.

Amino Acid Sequence↗
PubMed1997

Mutations in cornea-specific keratin K3 or K12 genes cause Meesmann's corneal dystrophy.

The intermediate filament cytoskeleton of corneal epithelial cells is composed of cornea-specific keratins K3 and K12 (refs 1,2). Meesmann's corneal dystrophy (MCD) is an autosomal dominant disorder causing fragility of the anterior corneal epithelium, where K3 and K12 are specifically expressed. We postulated that dominant-negative mutations in these keratins might be the cause of MCD. K3 was mapped to the type-II keratin gene cluster on 12q; and K12 to the type-I keratin cluster on 17q using radiation hybrids. We obtained linkage to the K12 locus in Meesmann's original German kindred (Zmax = 7.53; theta = 0) and we also showed that the phenotype segregated with either the K12 or the K3 locus in two Northern Irish pedigrees. Heterozygous missense mutations in K3 (E509K) and in K12 (V143L; R135T) completely co-segregated with MCD in the families and were not found in 100 normal unrelated chromosomes. All mutations occur in the highly conserved keratin helix boundary motifs, where dominant mutations in other keratins have been found to severely compromise cytoskeletal function, leading to keratinocyte fragility phenotypes. Our results demonstrate for the first time the molecular basis of Meesmann's corneal dystrophy.

Cornea↗
PubMed1997

Evidence for two psoriasis susceptibility loci (HLA and 17q) and two novel candidate regions (16q and 20p) by genome-wide scan.

In a 12.5 cM genome-wide scan for psoriasis susceptibility loci, recombination-based tests revealed linkage to the HLA region (Zmax = 3.52), as well as suggestive linkage to two novel regions: chromosome 16q (60-83.1 cM from pter, Zmax = 2.50), and chromosome 20p (7.5-25 cM from pter, Zmax = 2.62). All three regions yielded P values < or = 0.01 by non-parametric analysis. Recombination-based and allele sharing methods also confirmed a previous report of a dominant susceptibility locus on distal chromosome 17q (108.2 cM from pter, Zmax = 2.09, GENEHUNTER P = 0.0056). We could not confirm a previously reported locus on distal chromosome 4q; however, a broad region of unclear significance was identified proximal to this proposed locus (153.6-178.4 cM from pter, Zmax = 1.01). Taken together with our recent results demonstrating linkage to HLA-B and -C, this genome-wide scan identifies a psoriasis susceptibility locus at HLA, confirms linkage to 17q, and recommends two novel genomic regions for further scrutiny. One of these regions (16q) overlaps with a recently-identified susceptibility locus for Crohn's disease. Psoriasis is much more common in patients with Crohn's disease than in controls, suggesting that an immunomodulatory locus capable of influencing both diseases may reside in this region.

Adult↗