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Biomedical subjects

G Messer

Publications and source records attributed to G Messer.

At least 19 recordsLinked to original sources
PubMed1999

Structural analysis, expression, and chromosomal localization of the mouse ikba gene.

The pleiotropic transcription factor NF-kappaB is localized in the cytoplasm bound to its inhibitory subunit IkappaB. The predominant form of NF-kappaB is a p50/p65 heterodimer which can be released from IkappaB-alpha and migrate to the nucleus. Previous studies have shown that IkappaB-alpha-/- mice die 8 to 10 days postnatally, showing runting and a severe dermatitis. However, the organ distribution of mouse IkappaB-alpha, the exon-intron structure, and the chromosomal localization of ikba have not been determined so far. A mouse Sv129 genomic DNA library was screened with a human IkappaB-alpha/MAD-3 cDNA probe. One clone (P1) was isolated, spanning the complete ikba gene and the promoter/enhancer region. We show that the exon-intron structure between mouse and pig ikba is completely conserved. In contrast to human ikba, the ankyrin repeat 5 is not interrupted by an intron. Furthermore, the mouse ikba promoter contains 6 putative NF-kappaB binding sequences, which are conserved in mouse, pig, and human, underlining the importance of NF-kappaB as a key regulator of ikba transcription. The deduced amino acid sequence shows >90% similarity between mouse, pig, and human ikba. Chromosome mapping localized the mouse ikba gene to chromosome 12. Northern blot analysis demonstrated predominant expression in lymphoid tissue (lymph node and thymus). However, IkappaB-alpha mRNA was detected as well in liver tissue, the gastrointestinal tract, and the reproductive tract. The cloning and determination of the structure are a prerequisite for the construction of vectors for conditional gene targeting experiments.

Amino Acid Sequence↗
PubMed1999

Evidence for suppressed activity of the transcription factor NFAT1 at its proximal binding element P0 in the IL-4 promoter associated with enhanced IL-4 gene transcription in T cells of atopic patients.

Allergen-specific T cells in atopic patients are polarized IL-4-producing Th2 cells, promoting IgE synthesis by B cells. The molecular basis for increased IL-4 gene expression in atopy is not fully understood. IL-4 gene regulation in general involves the nuclear factor of activated T cells (NFAT) family of transcription factors, of which NFAT1 and NFAT2 are most prominent in peripheral T cells. Recently, a unique inhibitory role of NFAT1 in IL-4 gene control was shown in the mouse. In a series of electrophoretic mobility shift assays with protein extracts of highly polarized Th2 clones from atopics and Th1 clones from controls we compared DNA-binding activities at the two NFAT-binding elements P0 and P1 of the crucial proximal human IL-4 promoter. At the most proximal P0 site, NFAT-containing complexes devoid of NFAT2 were readily inducible in the Th1 clones, but hardly or not in the Th2 clones. In contrast, both in Th1 and Th2 clones NFAT-containing complexes were strongly inducible at the P1 site, consisting of NFAT2 and a P0-compatible NFAT activity, without apparent differences between Th1 and Th2 clones. Like in Th2 clones, suppressed NFAT-P0 complex formation was observed also at the polyclonal level in peripheral blood mononuclear cells (PBMC) of three of five severe atopic dermatitis patients with strongly elevated serum IgE levels, but not in control PBMC. These findings suggest that high-level IL-4 production in atopic Th2 cells is associated with selective reduction of suppressive NFAT1 activity at the IL-4 P0 element and that some patients with this multifactorial disease may have a putative systemic disorder at this level.

Animals↗
PubMed1998

Primary angiosarcoma of the ovary: a clinicopathologic, immunohistochemical and electronmicroscopic study.

The present report of a 25 year old woman with a primary ovarian angiosarcoma is supplemented by histochemical and ultrastructural studies and reviews the literature of this extremely rare neoplasm. Since this ovarian tumor, especially in young women, may constitute a diagnostic pitfall, problems relating to differential diagnosis are emphasized. Although the origin of this neoplasm appears to occur most likely from the rich ovarian vasculature, other less conventional histogenetic theories such as a possible origin in mixed mullerian tumor, in teratoma or in other ovarian germ cell tumors have also been proposed and are considered in this paper.

Actins↗
PubMed1998

Dorfman-Chanarin syndrome: morphologic studies and presentation of new cases.

Dorfman-Chanarin syndrome, or neutral lipid storage disease with ichthyosis, is a rare inherited metabolic disorder characterized by accumulation of neutral lipids in different tissues. Variability in dermatologic severity is not understood. We report two new cases, compare their features with other reported cases, and examine the possible relationship between the severity of the dermatologic condition and lipid accumulation in various types of skin cells. The localization of lipid droplets was determined in various dermal and epidermal cells by light microscopy of epoxy resin semithin sections and electron microscopy in four cases of Dorfman-Chanarin syndrome. Lipid droplets in the dermis were detected in fibroblasts, Schwann cells in both myelinated and unmyelinated nerves, smooth muscle cells, and sweat gland cells, but not in endothelial cells of blood capillaries. The droplets were not surrounded by a membrane. Findings indicate that there is no correlation between the clinical severity of the disease and the microscopic findings.

Adolescent↗
PubMed1998

Isolation of a hypoxia-induced cDNA with homology to the mammalian growth-related protein p23.

Hypoxia leads to a cellular stress reaction and can induce transcription of immediate early genes, such as c-fos. We have generated a differential cDNA cloning strategy to isolate further hypoxia-induced genes. We report on the identification and characterization of a novel transcript (cDNA clone pSH16), which is inducible 12-fold in HeLa cells after 50 min of exposure to hypoxia. Sequence analysis revealed a hybrid transcript with high homology to the mammalian growth-related protein p23 mRNA fused to mitochondrial 16S rRNA. Complete homology was found for the coding region, whereas the 3'-untranslated part of the hypoxia-induced p23 sequence was elongated and carried an ATTTA box and a second consensus poly(A) signal in addition. The functional integrity of the pSH16 mRNA was verified by cell-free translation. Hypoxia induced the expression of both fusion partners, p23 and 16S rRNA, separately. In contrast to the hypoxia-induced expression in HeLa cells, we found constitutive high-level expression in breast and cervix tissue. No further upregulation of p23 transcripts was detectable in primary tumors of the breast and cervix. These data provide first evidence for a hypoxia-induced upregulation of the mammalian growth-related protein p23, which might be relevant for understanding of the physiology of hypoxic conditions in tumors.

Amino Acid Sequence↗
PubMed1997

[MRI of fingers in systemic scleroderma. Initial results with contrast-enhanced studies using a dedicated MRI system].

PURPOSE: To estimate disease activity in patients with systemic sclerosis using contrast-enhanced MRI of the skin. MATERIAL AND METHODS: In a pre-study, sequences of a low-field (0.2 T) scanner (Artoscan, Esaote, Genova, Italy) were optimized for detection of intravenous contrast (0.1 mmol/l Gd-DTPA) in six patients with the autoimmune disease systemic scleroderma. Based on the results of the pre-study, 17 patients with scleroderma (7 sclerotic/10 active inflammatory disease) were scanned using gradient-spoiled 3D GRE sequences (FA 90 degrees, TR 100 ms, TE 18 ms), which had been established as most sensitive for intravenous contrast. Contrast enhancement of the skin was determined quantitatively by contrast-to-noise ratios (CNR), comparing post- to pre-contrast and dynamic scans (for 6 min, 1 acquisition/min). Patients in the chronic state with sclerodactylia and active inflammation of the hands were considered separately and compared to a control group (n = 10) matched according to age. RESULTS: CNR increase after intravenous contrast was significantly higher in patients with active disease (86 +/- 16% increase) than sclerosing disease (29 +/- 3%, p < 0.05) and the control group (4 +/- 2%, p < 0.05). The dynamic examination showed a significantly slower decrease after the peak rise in the first minute in patients with active disease (CNR 15.4 +/- 0.7 to 14.2 +/- 1.4) than in those with chronic disease (14.1 +/- 0.5 to 11.3 +/- 0.9, p < 0.05). DISCUSSION: Capillary leakage is the most likely explanation for the increased enhancement in patients with active scleroderma. Using sequences optimized for contrast detection, disease activity in the course of scleroderma and response to therapy can be determined by MRI in the future.

Adult↗
PubMed1997

Monitoring cholesterol crystallization from lithogenic model bile by time-lapse density gradient ultracentrifugation.

BACKGROUND/AIMS: Cholesterol crystallization in a dilute, bile salt-rich model bile is a multiphase process in which early filamentous crystals gradually transform to classical cholesterol monohydrate plates. The pertinence of similar transformations in more complex model systems or native bile is, however, unclear. The aim of the present study was to characterize and monitor cholesterol crystallization in a model bile of physiological relevance. METHODS: A supersaturated model bile was prepared with a lipid composition (18 mM cholesterol, 37 mM lecithin, 120 mM taurocholate) that was derived from analyzing 10 gallbladder biles from cholesterol gallstone patients. Cholesterol crystallization was followed by light and electron microscopy, and sequential density gradient analysis of cholesterol-containing precipitates. RESULTS: During cholesterol crystallization a reproducible sequence of events was recorded. First (T<18 h), cholesterol-rich vesicular and multilamellar structures (density 1.005-1.015 g/ml) were observed. Later, (T>60 h) filamentous, helical, tubular (density 1.015-1.04 g/ml) and plate-like (density 1.04-1.06 g/ml) cholesterol crystals appeared. The concentration of crystals increased gradually, while bilayer structures became desaturated with cholesterol and disappeared, and early crystal forms were replaced by plates. Eventually (T>25 days) only classical plate-like cholesterol monohydrate crystals were present. Exposure of cholesterol-containing precipitates to micellar (100 mM) deoxycholate dissolved the bilayer structures but not the crystals. CONCLUSIONS: These data demonstrate that cholesterol crystallization in a physiologically relevant model bile is a multiphase process consisting of a sequence of transitions from vesicular and multilamellar structures to early crystal forms and to classical plate-like cholesterol monohydrate crystals. These transitions are associated with increasing density and decreasing phospholipid content of cholesterol precipitates. We suggest that time-lapse density gradient ultracentrifugation is a useful method for investigating and quantitating the process of cholesterol crystallization and factors that influence this process in bile.

Animals↗
PubMed1997

Polymorphism of the tumour necrosis factor-alpha and lymphotoxin-alpha genes in hairy cell leukaemia.

Hairy cell leukaemia (HCL) is a rare chronic B lymphoproliferative disorder which can lead to severe pancytopenia and several immunologic abnormalities. The pathogenetic role of tumour necrosis factor (TNF)-alpha in HCL prompted us to study the potential contribution of functionally important genetic polymorphisms of the TNF gene cluster in a large group of patients with HCL. The TNF-alpha (-308 bp) promoter/enhancer point mutation and two polymorphisms located within the first intron of the lymphotoxin (LT)-alpha gene showed neither significant allelic deviation for the patient group nor, after analysis of clinical characteristics such as blood counts, stable or progressive disease or response to therapy.

Adult↗
PubMed1997

Polymorphism of the tumour necrosis factor-alpha and lymphotoxin-alpha genes in chronic lymphocytic leukaemia.

The neoplastic cells of CLL are able to produce TNF which is known to stimulate the proliferation of CLL cells in an autocrine and paracrine manner. Genetic polymorphism of molecules of the TNF ligand superfamily has been described and certain alleles were suspected to predispose to variant biological responses. Previously, the rare allele TNFB*1 of the TNF-beta/lymphotoxin (LT)-alpha gene (NcoI, asparagine at amino acid position 26) was found to be associated with a stronger LT-alpha response of PBMC in vitro. We now report on a significant increase of the allele TNF1 (TNFA -308 G) of the TNF-alpha promoter/enhancer polymorphism in a group of 73 CLL patients when compared to healthy individuals (RR = 3.18, 95% confidence interval 1.57-8.3; P = 0.006). The allelic distribution of the TNF-beta/LT-alpha NcoI polymorphism did not differ significantly from randomized healthy controls. On the other hand, the frequency of the allele TNFB*2 was increased in CLL patients with advanced clinical stage (P = 0.004). These findings indicate immunogenetic associations involving polymorphisms of cytokine genes serving as paracrine and autocrine growth factors, which thus can contribute to the pathogenesis of the TNF/LT-sensitive haematological malignancy CLL.

Adult↗
PubMed1997

Induction of interleukin 6 by ionizing radiation in a human epithelial cell line: control by corticosteroids.

The cutaneous radiation syndrome after therapeutic or accidental exposure of human skin to ionizing radiation (IR) is accompanied by inflammatory processes which are controlled partly by proinflammatory cytokines. Besides tumour necrosis factor (TNF)-alpha and interleukin (IL)1, the pluripotent cytokine IL-6 belongs to the key mediators of inflammation. So far, there are no reports about the regulation of IL-6 by IR in epidermal cells. As an in vitro model to study the effects of IR on IL-6 gene expression, we treated the human epithelial HeLa cell line with different single X-ray doses between 1 and 20 Gy. Twenty-four hours after irradiation the IL-6 secretion was dose-dependently enhanced as measured by ELISA. At the transcriptional level, a slight increase of IL-6 transcripts was already detectable 1 h after irradiation, with maximum levels at 2 h, and a decline to baseline levels between 8 and 24 h. Addition of the transcriptional inhibitor actinomycin D inhibited the inducibility of IL-6 mRNA by TPA and IR. As the IL-6 promoter contains multiple binding sites for activated glucocorticoid receptors within the 5' regulatory region, the potential modulation of IL-6 expression by the corticosteroids hydrocortisone, dexamethasone and mometasone furoate was included in our study to modify the radiation-induced stress response. All corticosteroids applied could efficiently downregulate TPA- or radiation-induced IL-6 expression on both gene expression and protein levels. Mometasone furoate, followed by dexamethasone, was found to be most effective at low concentrations (1 nM), whereas hydrocortisone had to be applied at about 100-fold higher concentrations to achieve comparable inhibition. This experimental model is aimed at understanding the molecular circuits following IR, and thus to provide a basis for the treatment of radiation effects in skin.

Adrenal Cortex Hormones↗
PubMed1997

Phototesting and photoprotection in LE.

Photosensitivity and induction of skin lesions following UV radiation is a common problem of patients with cutaneous and systemic forms of lupus erythematosus. The detrimental effect of UV radiation to patients with lupus erythematosus was already recognized in the last century. Skin lesions can now be provoked under standardized conditions allowing the diagnosis and classification of patients with photosensitive disorders. The aim of this review is to give an overview on the history, test procedure and test results in patients with lupus erythematosus.

History, 19th Century↗