Biomedical subjects
Publications and source records attributed to H Matthes.
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Collagenous colitis is characterized by the deposition of a superficial subepithelial collagenous layer, the pathogenesis of which is unknown. Because the excess matrix deposition is potentially reversible, a labile imbalance between fibrogenesis and fibrolysis may be suspected. Expression of procollagen alpha1(I) and alpha1(IV), matrix-metalloproteinase (MMP)-1 and -13, and tissue inhibitor of metalloproteinase (TIMP)-1 genes was semiquantitated by in situ hybridization on serial biopsies of 12 patients with collagenous colitis and compared to controls. Collagen types I, III, IV, and VI, tenascin, undulin/collagen XIV, and alpha-actin were localized by immunohistology. The superficial collagen layer stained strongly for collagen types I, III, and VI, and particularly for tenascin, but not for undulin. Elevated procollagen alpha1(I), procollagen alpha1(IV), and TIMP-1 transcript levels were found in alpha-actin-positive cells with linear distribution underneath the superficial collagenous layer, whereas MMP-1 RNA expression was variable and restricted to cell clusters. MMP-13 expression was undetectable. The patterns of procollagen alpha1(I)- and alpha1(IV)-specific labeling, combined with an intense tenascin- but absent undulin-specific staining, indicate deposition of an immature interstitial matrix that may be susceptible to degradation. The restricted MMP-1 RNA expression, counteracted by increased TIMP-1 expression, suggests locally impaired fibrolysis as a relevant factor in the pathogenesis of collagenous colitis.
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The aim of this study was to investigate the relationship between expression of sulphonylurea receptors (SUR) and metabolic rate (MR). SUR on monocytes and cells from muscle tissue were detected using fluorescent glibenclamide and flow cytometry. Transmembrane potential differences were detected by oxonol dye fluorescence measurements. A bovine model was used to induce differences in the MR by exposure to different ambient temperatures (4 degrees C and 18 degrees C), by different feeding levels (1.0- and 1.6-fold the metabolizable energy requirement for maintenance) and by alpha2-adrenergic stimulation. We found that cells from skeletal muscle (m. semimembranosus), immunochemically identified as smooth muscle cells, skeletal muscle fibres and monocytes, responded in comparable fashions to glibenclamide and ATP, i.e. with a depolarization, and to cromakalim with a polarization, suggesting that monocytes are useful indicators of regulatory events occurring in muscle cells. Glibenclamide fluorescence was assumed to represent SUR associated with KATP channels. Significant differences were detected in the percentage of depolarized monocytes in the different variants of the model. A linear correlation between monocytes that bound fluorescent glibenclamide and the MR was evident (with a coefficient of determination of 0.94) and was reproducible following reduction of the MR, by alpha2-adrenergic stimulation, suggesting that expression is involved in the regulation of whole-body energy expenditure.
BACKGROUND & AIMS: The initial step in tumor invasion and metastasis is determined by adhesion of tumor cells to basement membranes. To evaluate their potential therapeutic use in controlling local growth and metastasis, the effects of retinoids on the adhesive properties in the human pancreatic carcinoma cell line DAN-G were examined. METHODS: The effects of retinoids on cellular adhesion were assessed by adhesion assays in vitro. The expression of laminin-binding proteins was characterized by Northern blotting, radioimmunoprecipitation, and flow-cytometric analysis. RESULTS: Treatment with retinoids results in a time- and dose-dependent inhibition of DAN-G cell adhesion to fibronection and laminin but not to collagens I, IV, and VI. The adhesion of DAN-G cells to laminin could be blocked completely by anti-alpha 6 and anti-beta 1 antibodies but not by the synthetic peptide YIGSR. Flow-cytometric analysis of DAN-G cells showed no quantitative difference for alpha 6-integrin expression in retinoid-treated and -untreated DAN-G cells. Furthermore, radioimmunoprecipitation showed no difference in the appearance of alpha 6 beta 1-integrin expression after retinoid incubation. CONCLUSIONS: Retinoids decrease pancreatic carcinoma cell adhesion to laminin via an as yet unidentified mechanism involving alteration of the alpha 6 beta 1-integrin receptor function and thereby open interesting perspectives for the modulation of infiltrative growth and metastasis in pancreatic cancer.
An opioid-like receptor has been cloned by several groups of researchers and recently shown to be activated by an endogenous heptadecapeptide termed orphanin FQ (or nociceptin). We isolated the corresponding mouse cDNA and coexpressed it in Xenopus laevis oocytes with the potassium channel subunits Kir3.1 (GIRK1) and Kir3.4 (CIR, rcKATP). Orphanin FQ evoked potassium currents, with 50% of the maximal effect at approximately 1 nM; [Tyr1]orphanin FQ was equally effective, and des-pheorphanin FQ was without activity. Dynorphin A, dynorphin(1-9), dynorphin(1-13), and alpha-neoendorphin were > 100 times less potent, and other agonists active at mu-, delta-, and kappa-opioid receptors had no effect. Naloxone (1 microM) and norbinaltorphimine (1 microM) had no antagonist action. Conversely, oocytes expressing kappa receptors responded to dynorphin (half-maximal concentration, 0.3 nM) but not to orphanin FQ. Thus, both kappa and orphanin FQ receptors readily couple to potassium channels, but the highly selective activation by dynorphin and orphanin FQ is consistent with distinct functional pathways in vivo.
Using the mouse delta-opioid receptor cDNA as a probe, we have isolated genomic clones encoding the human mu- and kappa-opioid receptor genes. Their organization appears similar to that of the human delta receptor gene, with exon-intron boundaries located after putative transmembrane domains 1 and 4. The kappa gene was mapped at position q11-12 in human chromosome 8. A full-length cDNA encoding the human kappa-opioid receptor has been isolated. The cloned receptor expressed in COS cells presents a typical kappa 1 pharmacological profile and is negatively coupled to adenylate cyclase. The expression of kappa-opioid receptor mRNA in human brain, as estimated by reverse transcription-polymerase chain reaction, is consistent with the involvement of kappa-opioid receptors in pain perception, neuroendocrine physiology, affective behavior, and cognition. In situ hybridization studies performed on human fetal spinal cord demonstrate the presence of the transcript specifically in lamina II of the dorsal horn. Some divergences in structural, pharmacological, and anatomical properties are noted between the cloned human and rodent receptors.
BACKGROUND/AIMS: Following malignant transformation, epithelial cells of colorectal carcinomas, unlike normal colonic epithelial cells, no longer express the alpha 5 beta 1 fibronectin receptor. We hypothesized that the loss of alpha 5 beta 1 expression might facilitate the tumorigenicity of transformed colonic cells. METHODS: To examine this hypothesis, we established subclones of the human colon adenocarcinoma cell line HT 29, which differ in their fibronectin receptor expression and tested their tumorigenicity in nude mice. RESULTS: Our data indicate that the capacity to form tumors in nude mice after subcutaneous injection was significantly lower for alpha 5-positive than for alpha 5-negative cell clones. In addition, tumors from clones expressing no detectable levels of alpha 5 beta 1 grew rapidly, whereas tumors expressing elevated levels of fibronectin receptor grew slowly. Despite similar rates of adhesion to fibronectin for alpha 5-positive and alpha 5-negative cell clones in vitro, deposition of fibronectin in tumor-surrounding stroma was increased in tumors derived from alpha 5-positive cells. CONCLUSIONS: Our results indicate that an increase of the alpha 5 beta 1-mediated interaction of malignant cells with the extracellular matrix may be responsible for decreased tumorigenicity of malignant transformed cells in colorectal carcinomas.
Although pleiotropic effects of glucocorticoids on the endocrine and exocrine pancreas are well documented, it remains controversial whether these effects are due to direct interactions of glucocorticoid hormones with their receptors in the respective target cells. We therefore examined gene expression of the glucocorticoid receptor (GR) in various functional compartments of the rat pancreas. Using in situ hybridization by generating a radioactive cRNA probe from a specific cDNA clone for the rat glucocorticoid receptor we found a gradient in the expression of receptor mRNA transcripts from endocrine > acinar > ductal cells. In contrast, no specific hybridization signal was observed in the endothelial cells of vascular structures. Using a monospecific polyclonal antibody against the rat glucocorticoid receptor in Western blot analyses we found significant expression of the 94 kD receptor protein in an enriched pancreatic acinar cell preparation. This data suggest that rat pancreatic exocrine cells might serve a direct target tissue for glucocorticoid action.
We have used the mouse delta-opioid receptor (mDOR) cDNA to isolate the mDOR gene and its human homologue. In both species the coding region is interrupted by two introns with conserved exon-intron boundaries located after transmembrane domains 1 and 4. Using the polymerase chain reaction and primers based on the sequence of the cloned human delta-opioid receptor (hDOR) gene, we have obtained a full length cDNA encoding the hDOR from SH-SY5Y neuroblastoma cells. The cDNA sequence is 100% identical to the cloned human genomic sequence and 94% identical to the mouse sequence at the protein level. When expressed in COS cells, hDOR displays nanomolar affinities for delta-selective ligands, whereas the affinities for mu- and kappa-selective ligands are in the micromolar range. The delta agonists [D-Ala2, D-Leu5]enkephalin, cyclic [D-penicillamine2,D-penicillamine5]enkephalin, and BW373U86 efficiently decrease forskolin-induced cAMP levels in hDOR-expressing COS cells, indicating functional coupling of the receptor. The distribution of hDOR mRNA in human brain was investigated using delta-selective reverse transcription-polymerase chain reaction amplification, followed by Southern hybridization with a delta-specific probe. The transcript is found in cortical areas, including olfactory bulb, hippocampus, and amygdala, as well as in basal ganglia and hypothalamus. No expression is detected in internal globus pallidus, thalamus, any investigated brainstem structure, or pituitary gland. Taken together, our results indicate similar structural, pharmacological, functional, and anatomical properties for the hDOR and the mDOR and therefore support the use of rodent models for the study of these receptors in opioid function.
Very little is currently known regarding the underlying mechanisms involved in the etiology of intestinal strictures in chronic inflammatory bowel disease. The deposition of extracellular matrix components, especially collagens, is thought to play an important role in the etiology of intestinal strictures. The main goal of this study was therefore to investigate the collagen metabolism in patients with inflammatory bowel disease using the in situ hybridization technique. We determined de novo synthesis of the (pro)-collagen mRNA transcripts alpha 1I, alpha 1III, alpha 1IV, alpha 2V as well as the collagen degrading enzyme mRNA transcripts collagenase type I and IV in Crohn's disease and ulcerative colitis and compared the rate of expression semiquantitatively to healthy controls. We found a significant increase of all (pro)-collagen transcripts tested in Crohn's disease and ulcerative colitis as compared to healthy control tissues, indicating an increased de novo synthesis of all collagens in both inflammatory bowel diseases. However, we observed a significant difference in the expression of the collagenase mRNA transcripts between Crohn's disease and ulcerative colitis. Compared to healthy control subjects we were unable to detect a significant difference in the expression of collagenase type I and IV in Crohn's disease; in contrast, we observed a significant increase in the rate of expression for the collagenases in ulcerative colitis as compared to controls or biopsies from patients with Crohn's disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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The percutaneous absorption of diflucortolone-21-valerate (DFV) and its effect on the pituitary adrenal system were investigated during large skin area treatment (20 g ointment twice a day for 8 days) of two groups of healthy volunteers with Nerisona and Nerisalic ointment, respectively. Plasma levels of diflucortolone, cortisol and dehydroepiandrosterone (DHEA) were measured in both groups whereas plasma levels of salicylic acid were measured additionally in volunteers treated with Nerisalic. No differences, neither in percutaneous absorption of DFV nor in effects on cortisol and DHEA were found between the two treatment groups. There was a slight reduction in cortisol levels under both treatments, but the circadian rhythm was not disturbed. Mean salicylic acid plasma levels under high-dose topical Nerisalic treatment were about 50-fold below levels where toxicity may be expected.
The Tecnomouse system is useful for cultivating transformed cell lines producing MAbs or recombinant proteins, but human tumor cells can also be propagated for autologous immunization protocols or research properties. Lymphokine-activated killer cell production and stem cell proliferation seem to be possible. Moreover, primary human cells of lymphoid organs can be successfully kept viable over long periods of time in a three-dimensional, tissue-like culture. Therefore, the bioreactor is a tool for the in vitro modulation of a variety of human organs.