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Ledig S, Wagner S, Manns MP, Beil W, Athmann C. Role of the receptor-mediated apoptosis in Helicobacter pylori in gastric epithelial cells. Digestion 2005; 70:178-86. [PMID: 15557763 DOI: 10.1159/000082252] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Accepted: 07/21/2004] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIMS Two major pathways leading to apoptosis have been described. It has been shown that Helicobacter pylori-mediated apoptosis is mainly effected through the mitochondrial pathway (type II). The role of the type I pathway, including the death receptors, has been discussed controversially. Therefore, we investigated the role of Fas ligand (FasL) and TRAIL in H. pylori-mediated apoptosis by overexpressing antiapoptotic proteins in the human gastric epithelial cell line AGS. METHODS AGS cells overexpressing the antiapoptotic proteins dnFADD, CrmA and Bcl-2 were generated. Apoptosis induced by Fas and H. pylori was monitored by histone ELISA. To investigate the role of TRAIL-mediated apoptosis, AGS cells were transduced with antisense constructs against the proapoptotic TRAIL receptors DR4 and DR5. Protein expression of Fas, TRAIL, DR4, and DR5 was analyzed by Western blot. RESULTS Fas and H. pylori-mediated apoptosis was significantly inhibited in all generated cell lines, mainly in cells overexpressing CrmA and Bcl-2 with equal effectiveness. In the presence of H. pylori, TRAIL ligand and DR5 receptor were continuously expressed whereas DR4 expression was increasing time dependently. TRAILDR5 antisense significantly reduced H. pylori-mediated apoptosis. CONCLUSIONS H. pylori-mediated apoptosis is characterized by activation of either type I or type II pathway. Caspase-8 plays an important role since it triggers the Type II pathway. Fas and TRAIL play an important role in the H. pylori-mediated apoptosis.
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Affiliation(s)
- S Ledig
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Hannover, Germany
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Bleich A, Köhn I, Glage S, Beil W, Wagner S, Mähler M. Multiple in vivo passages enhance the ability of a clinical Helicobacter pylori isolate to colonize the stomach of Mongolian gerbils and to induce gastritis. Lab Anim 2005; 39:221-9. [PMID: 15901366 DOI: 10.1258/0023677053739800] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Mongolian gerbil is an excellent animal model for Helicobacter pylori-induced gastritis in humans. In this study, initially low colonization rates of the H. pylori strains ATCC 43504, SS1, or HP87 inoculated into gerbils caused difficulties in establishing this model. In order to increase the colonization ability and pathogenicity, the clinical HP87 isolate was selected for adaptation to the gerbil stomach by multiple in vivo passages through gerbils. Development of gastritis was examined histologically at 4-52 weeks after infection. The proportion of gerbils which tested positive for H. pylori by culture at four weeks after inoculation gradually increased from 11.1% of gerbils inoculated with HP87 without prior in vivo passage (P0) to 100% of gerbils inoculated with HP87 with seven in vivo passages (P7). In addition, adaptation of HP87 resulted in more severe histopathological changes. Gerbils infected with adapted HP87 (P7) exhibited severe infiltration by monomorphonuclear and polymorphonuclear leukocytes in the mucosa, submucosa, and subserosa of the gastric antrum, as well as epithelial changes consisting of hyperplasia, erosion, and ulceration. Histopathological changes increased in severity from four to 52 weeks after infection. Adaptation of HP87 during its passages through gerbils could be due to genetic changes in bacterial colonization factors. Identification of these changes might be useful to understand the underlying mechanism of gastric adaptation and pathogenesis of H. pylori.
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Affiliation(s)
- A Bleich
- Institute for Laboratory Animal Science and Central Animal Facility, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
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Beil W. Der Washingtoner Kongreß der Internationalen Vereinigung für gewerbl. Rechtsschutz. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330281014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Beil W. Auf dem Wege zu einem europäischen Patentrecht. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330281218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Beil W. Internationale Diskussion über den Stoffschutz für chemische Erfindungen. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330260821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Beil W. Naturprodukte als Ausnahme vom Stoffschutz für chemische Erzeugnisse. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330241218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Beil W. Unzulässige und zulässige Photokopien. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330271229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Beil W. Zulässige und unzulässige Photokopien. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330241018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Beil W. Europäisches (EWG-) Kartellrecht III. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330341218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Beil W. Richtlinien für die Vergütung von Arbeitnehmererfindungen (II). CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330240916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Beil W. Richtlinien für die Vergütung von Arbeitnehmererfindungen (I). CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330240816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Beil W. Das Fünfte Überleitungsgesetz auf dem Gebiet des gewerblichen Rechtsschutzes I. CHEM-ING-TECH 2004. [DOI: 10.1002/cite.330251219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
During the last few years 3 important drugs (terfenadine, mibefradil, cisapride) had to been withdrawn from the market because of serious drug-drug interactions. Polypragmacy, not only in advanced age, is often applied. Consequently the possibility of pharmacokinetic and/or pharmacodynamic drug interactions has always to be taken into account which can cause adverse effects, therapeutic failures, hospital admissions and extra costs. Clinically relevant interactions can be observed especially on the level of drug metabolism and transport. Both pharmacokinetic processes can be induced or inhibited by numerous agents. Taking proton pump inhibitors as an example it could be shown that the various compounds can differ in their interaction potential.
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Affiliation(s)
- U Klotz
- Dr.-Margarete-Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart.
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Ramm W, Schatton W, Wagner-Döbler I, Wray V, Nimtz M, Tokuda H, Enjyo F, Nishino H, Beil W, Heckmann R, Lurtz V, Lang S. Diglucosyl-glycerolipids from the marine sponge-associated Bacillus pumilus strain AAS3: their production, enzymatic modification and properties. Appl Microbiol Biotechnol 2003; 64:497-504. [PMID: 14593508 DOI: 10.1007/s00253-003-1471-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2003] [Revised: 09/19/2003] [Accepted: 09/19/2003] [Indexed: 11/25/2022]
Abstract
The marine strain Bacillus pumilus strain AAS3, isolated from the Mediterranean sponge Acanthella acuta, produced a diglucosyl-glycerolipid, 1,2-O-diacyl-3-[beta-glucopyranosyl-(1-6)-beta-glucopyranosyl)]glycerol, with 14-methylhexadecanoic acid and 12-methyltetradecanoic acid as the main fatty acid moieties (GGL11). On a 30 l scale, using artificial seawater supplemented with glucose (20 g/l), yeast extract (10 g/l), and suitable nitrogen/phosphate sources, growth-associated glycoglycerolipid production reached its maximum yield of 90 mg/l after 11 h. Lipase-catalyzed modification of the native substance led to the deacylated parent compound (GG11), which could be reacylated using the same enzyme system to afford a new dipentenoyl-diglucosylglycerol (GGL12) as the major product upon addition of 4-pentenoic acid to the medium. GGL11 decreased the surface tension of water from 72 mN/m to 29 mN/m and the interfacial tension of the water/ n-hexadecane system from 44 to 5 mN/m. Anti-tumor-promoting studies on this class of diglucosyl glycerol products showed that the carbohydrate/glycerol backbone (GG11) has a more potent inhibitory activity than the acylated compounds. The diglucosyl-glycerol GG11 strongly inhibited growth of the tumor cell lines HM02 and Hep G2 (50% inhibition at approximately 1 microg/ml), while the glycerolipids GGL11 and GGL12 were less active or had no effect.
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Affiliation(s)
- W Ramm
- Institute of Biochemistry and Biotechnology, Biotechnology Group, Technical University of Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
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Potthoff A, Ledig S, Martin J, Jandl O, Cornberg M, Obst B, Beil W, Manns MP, Wagner S. Significance of the caspase family in Helicobacter pylori induced gastric epithelial apoptosis. Helicobacter 2002; 7:367-77. [PMID: 12485124 DOI: 10.1046/j.1523-5378.2002.00112.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND AIMS H. pylori infection results in an increased epithelial apoptosis in gastritis and duodenal ulcer patients. We investigated the role and type of activation of caspases in H. pylori-induced apoptosis in gastric epithelial cells. METHODS Differentiated human gastric cancer cells (AGS) and human gastric mucous cell primary cultures were incubated with H. pylori for 0.5-24 hours in RPMI 1640 medium, and the effects on cell viability, epithelial apoptosis, and activity of caspases were monitored. Apoptosis was analyzed by detection of DNA-fragments by Hoechst stain(R), DNA-laddering, and Histone-ELISA. Activities of caspases were determined in fluorogenic assays and by Western blotting. Cleavage of BID and release of cytochrome c were analyzed by Western blot. Significance of caspase activation was investigated by preincubation of gastric epithelial cells with cell permeable specific caspase inhibitors. RESULTS Incubation of gastric epithelial cells with H. pylori caused a time and concentration dependent induction of DNA fragmentation (3-fold increase), cleavage of BID, release of cytochrome c and a concomittant sequential activation of caspase-9 (4-fold), caspase-8 (2-fold), caspase-6 (2-fold), and caspase-3 (6-fold). No effects on caspase-1 and -7 were observed. Activation of caspases preceded the induction of DNA fragmentation. Apoptosis could be inhibited by prior incubation with the inhibitors of caspase-3, -8, and -9, but not with that of caspase-1. CONCLUSIONS Activation of certain caspases and activation of the mitochondrial apoptotic pathway are essential for H. pylori induced apoptosis in gastric epithelial cells.
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Affiliation(s)
- A Potthoff
- Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Germany
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Kalesse M, Christmann M, Bhatt U, Quitschalle M, Claus E, Saeed A, Burzlaff A, Kasper C, Haustedt LO, Hofer E, Scheper T, Beil W. The chemistry and biology of ratjadone. Chembiochem 2001; 2:709-14. [PMID: 11828509 DOI: 10.1002/1439-7633(20010903)2:9<709::aid-cbic709>3.0.co;2-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- M Kalesse
- Institut für Organische Chemie der Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany.
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Abstract
BACKGROUND In duodenal ulcer patients, intragastric acidity during omeprazole treatment is significantly lower before Helicobacter pylori eradication than after cure. AIMS To determine if H pylori enhances the acid inhibitory potency of omeprazole in isolated parietal cells and on H(+)/K(+)-ATPase. METHODS Rat parietal cells and pig gastric membrane vesicles enriched in H(+)/K(+)-ATPase activity were incubated with H pylori and the H pylori fatty acid cis 9,10-methyleneoctadecanoic acid (MOA), and the inhibitory effects of omeprazole on parietal cell acid production, H(+)/K(+)-ATPase enzyme activity, and ATPase mediated proton transport were assessed. RESULTS In isolated parietal cells, H pylori and MOA increased the acid inhibitory potency of omeprazole 1.8 fold. H pylori did not affect the inhibitory potency of omeprazole on H(+)/K(+)-ATPase enzyme activity. In proton transport studies, H pylori (intact bacteria and sonicate) and MOA accelerated the onset of the inhibitory effect of omeprazole and enhanced the proton dissipation rate in response to omeprazole. H. pylori itself increased proton permeability at the vesicle membrane. CONCLUSION Our results show that H pylori augments the acid inhibitory potency of omeprazole in parietal cells and enhances omeprazole induced proton efflux rate from gastric membrane vesicles. We suggest that omeprazole unmasks the permanent effect of H pylori on proton permeability at the apical parietal cell membrane, which is counteracted in the absence of a proton pump inhibitor by a reserve H(+)/K(+)-ATPase capacity.
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Affiliation(s)
- W Beil
- Department of General Pharmacology, Hannover Medical School, Hannover, Germany.
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Mix H, Widjaja A, Jandl O, Cornberg M, Kaul A, Göke M, Beil W, Kuske M, Brabant G, Manns MP, Wagner S. Expression of leptin and leptin receptor isoforms in the human stomach. Gut 2000; 47:481-6. [PMID: 10986207 PMCID: PMC1728089 DOI: 10.1136/gut.47.4.481] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Leptin is an important regulator of food intake and energy expenditure. Initially it was thought to be expressed exclusively in and secreted by adipocytes. Recently, leptin expression was also noted in other tissues, including rat gastric mucosa. Information on leptin and leptin receptor expression in the human stomach is lacking. AIM To investigate expression of leptin and its corresponding receptors in human gastric epithelial cells. METHODS Fundic and antral gastric mucosal biopsies, primary cultures of human gastric epithelial cells, and the human gastric cancer cell line AGS were screened for expression of leptin and different leptin receptor isoform mRNA by reverse transcriptase-polymerase chain reaction. Immunohistochemistry was performed for localisation of leptin and leptin receptor proteins in gastric mucosa. RESULTS mRNA of leptin and its four receptor isoforms (huOB-R, long receptor isoform; huB219.1-3, short receptor isoforms) was detected in gastric mucosal biopsies, cultured human gastric epithelial cells, and gastric cancer cells. Immunohistochemistry demonstrated that chief as well as parietal cells were reactive to leptin and leptin receptors. CONCLUSIONS Leptin and leptin receptors are expressed in human gastric mucosa. These findings suggest a paracrine and/or autocrine effect of leptin on gastric epithelial cell function.
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Affiliation(s)
- H Mix
- Department of Gastroenterology and Hepatology, Medizinische Hochschule Hannover, Germany
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Abstract
Helicobacter pylori infection has been associated with stimulation of gastric mucosal reactive oxygen species (ROS) production, and it was postulated that ROS production is due to neutrophil infiltration and activation. The aim of this study was to investigate the direct effect of H. pylori on ROS formation in gastric epithelial cells in vitro. The human gastric cancer cell line HM02 was incubated with H. pylori for 24 hr, and the effects on cell number and the intracellular radical scavenger reduced glutathione (GSH) were assessed. H. pylori caused a concentration-dependent reduction of cellular GSH concentrations over a broad bacteria-to-cell ratio (1.4-42) in the absence of cell necrosis. The radical scavengers MnTBAP (a cell permeable superoxide dismutase) and ebselen provided protection against H. pylori-induced decrease in cellular GSH concentrations. We conclude that H. pylori directly decreases cellular GSH concentrations in gastric epithelial cells. We suggest that this effect is caused by the release of ROS by H. pylori.
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Affiliation(s)
- W Beil
- Department of General Pharmacology, Hannover Medical School, Germany
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Abstract
Helicobacter pylori infection has been considered as a risk factor for gastric carcinoma. Strong evidence exists that reactive oxygen species (ROS) play an important role in carcinogenesis, and in vivo investigations have shown increased synthesis of ROS in the gastric mucosa of H.pylori-infected patients. In the present study the direct effects of H.pylori on ROS and DNA synthesis, induction of apoptosis and DNA repair were investigated in the gastric epithelial cell lines AGS and HM02. Incubation of gastric cells with H.pylori extract induced the synthesis of ROS, diminished the levels of reduced glutathione (GSH), induced DNA fragmentation and increased DNA synthesis in gastric cells. Poly(ADP-ribose) formation was increased in gastric cells exposed to H.pylori extract. FACS analysis of gastric cells exposed to H.pylori extract did not reveal any change in the percentage of cells in the G(2)/M phase of the cell cycle. The radical scavengers MnTBAP (a cell permeable superoxide dismutase mimic), ebselen (a GSH peroxidase mimic) and high doses of catalase completely blocked H.pylori extract-induced elevation in DNA synthesis. Our results indicate that H.pylori extract directly induces the synthesis of ROS in gastric epithelial cells and causes DNA damage.
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Affiliation(s)
- B Obst
- Department of General Pharmacology, Hannover Medical School, D-30625 Hannover, Germany
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Abstract
Helicobacter pylori infection has been considered as a risk factor for gastric carcinoma. Strong evidence exists that reactive oxygen species (ROS) play an important role in carcinogenesis, and in vivo investigations have shown increased synthesis of ROS in the gastric mucosa of H.pylori-infected patients. In the present study the direct effects of H.pylori on ROS and DNA synthesis, induction of apoptosis and DNA repair were investigated in the gastric epithelial cell lines AGS and HM02. Incubation of gastric cells with H.pylori extract induced the synthesis of ROS, diminished the levels of reduced glutathione (GSH), induced DNA fragmentation and increased DNA synthesis in gastric cells. Poly(ADP-ribose) formation was increased in gastric cells exposed to H.pylori extract. FACS analysis of gastric cells exposed to H.pylori extract did not reveal any change in the percentage of cells in the G(2)/M phase of the cell cycle. The radical scavengers MnTBAP (a cell permeable superoxide dismutase mimic), ebselen (a GSH peroxidase mimic) and high doses of catalase completely blocked H.pylori extract-induced elevation in DNA synthesis. Our results indicate that H.pylori extract directly induces the synthesis of ROS in gastric epithelial cells and causes DNA damage.
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Affiliation(s)
- B Obst
- Department of General Pharmacology, Hannover Medical School, D-30625 Hannover, Germany
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Schimana J, Fiedler HP, Groth I, Süssmuth R, Beil W, Walker M, Zeeck A. Simocyclinones, novel cytostatic angucyclinone antibiotics produced by Streptomyces antibioticus Tü 6040. I. Taxonomy, fermentation, isolation and biological activities. J Antibiot (Tokyo) 2000; 53:779-87. [PMID: 11079799 DOI: 10.7164/antibiotics.53.779] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two novel angucyclinone-type antibiotics, simocyclinones D4 and D8, were detected in the mycelium extract of Streptomyces antibioticus Tü 6040 by HPLC-diode-array and HPLC-electrospray-mass-spectrometry screening. The compounds show antibiotic activities against Gram-positive bacteria and cytostatic effects on various tumor cell lines.
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Affiliation(s)
- J Schimana
- Mikrobiologisches Institut, Universität Tübingen, Germany
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Beil W, Enss ML, Müller S, Obst B, Sewing KF, Wagner S. Role of vacA and cagA in Helicobacter pylori inhibition of mucin synthesis in gastric mucous cells. J Clin Microbiol 2000; 38:2215-8. [PMID: 10834979 PMCID: PMC86767 DOI: 10.1128/jcm.38.6.2215-2218.2000] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to investigate the effect of Helicobacter pylori on the function of gastric mucous cells. H. pylori (10(4) to 10(7) CFU/well) was incubated with the mucin-producing gastric cell line HM02 for 12 and 24 h. Mucin synthesis and secretion were determined by the incorporation of D-N-[acetyl-(14)C]glucosamine into intracellular and released high-molecular-weight glycoproteins. cagA-positive, cytotoxin-producing and non-cytotoxin-producing H. pylori strains impaired the incorporation of D-N-[acetyl-(14)C]glucosamine into intracellular glycoproteins. Significant inhibition of mucin synthesis was noted after 12 and 24 h of cocultivation with a bacterial load of >/=10(5) bacteria (bacterium/cell ratio = 0.25). The cagA-positive, cytotoxin-producing strains (HP64, HP57, and HP87) caused significantly stronger inhibition of intracellular mucin synthesis than the cagA-positive, non-cytotoxin-producing strains (HP05, HP83, and HP84). The cagA-negative, non-cytotoxin-producing strains (HP01, HP04, and HP85) did not affect intracellular mucin synthesis. The results indicate that H. pylori directly impairs mucin synthesis in gastric mucous cells and that cytotoxic cagA-positive strains cause more profound inhibition of mucin synthesis. We suggest that the increased inhibitory effect of cagA-positive, cytotoxin-producing strains on mucin synthesis can be considered one possible factor responsible for the increased risk of developing peptic ulceration with these H. pylori strains.
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Affiliation(s)
- W Beil
- Department of General Pharmacology, Medizinische Hochschule Hannover, D-30625 Hannover, Germany
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Enss ML, Cornberg M, Wagner S, Gebert A, Henrichs M, Eisenblätter R, Beil W, Kownatzki R, Hedrich HJ. Proinflammatory cytokines trigger MUC gene expression and mucin release in the intestinal cancer cell line LS180. Inflamm Res 2000; 49:162-9. [PMID: 10858016 DOI: 10.1007/s000110050576] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES AND DESIGN Proinflammatory cytokines and a defective mucus layer are involved in the pathogenesis of colitis. Therefore, we determined cytokine effects on MUC gene expression and mucin secretion. MATERIALS AND METHODS LS180 cells were characterized by light and electron microscopy and subsequently exposed to interleukin 1 (IL-1, 1 ng/ml), interleukin 6 (IL-6, 10 ng/ml), or tumor necrosis factor-alpha (TNFalpha, 10 ng/ml). MUC gene (MUC2, MUC5AC, MUC5B, MUC6) mRNA expression was assessed by RT-PCR, the encoded proteins were identified by immunocytochemistry and Western blotting, and the released mucins were isolated and chromatographically characterized. RESULTS Thirty to 40% of the cells contained intracellular mucin granules. Incubation with IL-1 transiently stimulated the mRNA expression of MUC2 and MUC5AC, whereas IL-6 induced an early response of MUC2, MUC5B and MUC6. TNFalpha upregulated the expression of MUC2 and MUC5B for 3 hours, and had no effect on the expression of MUC 5AC and MUC6. Immunocytochemistry and Western blotting confirmed TNFalpha effects on MUC2 and MUC5AC on the protein levels. All cytokines stimulated the release of less glycosylated mucins and considerably modulated their carbohydrate composition. CONCLUSION Our data demonstrate differential cytokine effects on mucin synthesis, secretion and composition. These alterations may contribute to the defective mucus layer in colitis.
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Affiliation(s)
- M L Enss
- Institute for Laboratory Animal Science and Animal Facility, Medical School Hannover, Germany
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Abstract
Four new polyketides, named rubiginone D2 (2), 4-O-acetyl-rubiginone D2 (3), rubiginone H (6) and rubiginone I (7) were isolated from the cultures of Streptomyces sp. (strain Gö N1/5). Their structures were established by a detailed spectroscopic analysis. The absolute configuration of 3 was determined by derivatization with chiral acids (Helmchen's method). The rubiginones inhibit the growth of some Gram-positive bacteria and are cytostatically active against different tumor cell lines.
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Affiliation(s)
- C Puder
- Institut für Organische Chemie, Universität Göttingen, Germany
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Cornberg M, Enss ML, Makkink MK, Beil W, Bock CT, Sobek-Klocke I, Mix H, Hiller W, Manns MP, Wagner S. Variation of human mucin gene expression in gastric cancer cell lines and gastric mucous cell primary cultures. Eur J Cell Biol 1999; 78:832-41. [PMID: 10604660 DOI: 10.1016/s0171-9335(99)80034-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Human gastric mucous cells - gastric cancer cell lines mucin gene expression - TNFalpha - RT-PCR immunocytochemistry Little is known on the expression pattern of mucin genes in human gastric cancer cell lines in relation to mucin expression in normal gastric epithelial cells. Thus, the aim of this study was to compare gastric cancer cell lines and non-transformed epithelial cells in their expression of the different mucin genes, in order to use these cells as models for physiological MUC expression in human stomach. Human gastric mucous cell primary cultures which were obtained from surgical specimen by collagenase/pronase treatment and a panel of six human gastric cancer cells were screened for mRNA expression of the mucin genes MUC1, MUC2, MUC5AC, MUC5B, and MUC6. Mucin gene expression was analyzed by semi-quantitative RT-PCR, and by Western blotting and immunocytochemistry. Primary cultured human gastric mucous cells retained the stomach-specific pattern of mRNA expression found in gastric mucosal biopsies (MUC1, MUC5AC, MUC6), whereas any gastric cancer cell line exhibited an aberrant mucin gene expression. Mucin gene expression showed large variations in levels and patterns from cell line to cell line, but MUC2 was aberrantly expressed in all cancer cells. Immunocytochemistry confirmed aberrant MUC2 protein expression in cancer cells. The expression of the secretory mucin genes MUC2 and MUC5AC varied in relation to the length of cultivation of the cancer cell lines. Treatment of the gastric cancer cells with TNFalpha resulted in an enhanced mRNA expression of MUC1, MUC2, and MUC5AC (2-fold increase within 3 hours; p <0.05). In contrast, immunocytochemistry disclosed a decrease in MUC2 and MUC5AC staining intensity. Our results indicate that primary cultured human gastric mucous cells provide a physiological in vitro system for investigations of gastric mucin gene regulation. In gastric cancer cells marked changes in the mucin gene expression pattern are found with coexpression of non-gastric type mucins. Gastric mucin gene expression may be regulated by proinflammatory cytokines which could have implications in gastritis.
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Affiliation(s)
- M Cornberg
- Department of Gastroenterology and Hepatology, Medizinische Hochschule Hannover, Germany
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Abstract
Pantoprazole sodium is a substituted benzimidazole derivative which controls acid secretion by inhibition of gastric H(+)/K(+)-ATPase. The prodrug pantoprazole accumulates in the acidic space of the parietal cell where it is converted to the pharmacologically active principle, a thiophilic cyclic sulfenamide. The pH-dependent activation profile, i.e., activation at pH 1 versus activation at pH 4-6, is more favorable for pantoprazole than for the other proton pump inhibitors (PPIs) currently available. In vitro, pantoprazole interferes less potently than omeprazole with biological targets not related to gastric acid secretion. The gastric target sites for the pantoprazole sulfenamide are the cysteines 813 and 822 of the catalytic subunit of the H(+)/K(+)-ATPase. In contrast to omeprazole, the two binding sites are located right at the proton channel. In rats, dogs and humans, pantoprazole produces marked and prolonged inhibition of both basal and stimulated acid secretion. Overall, its antisecretory potency is equal to that of omeprazole. Antiulcer activity has been demonstrated for pantoprazole in two rat models. As seen with H(2)-receptor antagonists and other PPIs, pantoprazole causes an increase in serum gastrin concentration which reflects the degree of gastric acid inhibition. Pantoprazole is mainly metabolized by CYP3A4 and 2C19, but displays a lower affinity for these phase I cytochrome P450 enzymes than omeprazole. In contrast to the latter, pantoprazole is further conjugated with sulfate by the hepatic phase II metabolism. These two differences may explain why pantoprazole does not interfere with the metabolism of any other drug thus far tested in humans.
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Affiliation(s)
- W Beil
- Institute of General Pharmacology, Hannover Medical School, Hannover, Germany
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Bertram-Drogatz PA, Sobek-Klocke I, Möller C, Wingbermühle D, Beil W, Sewing KF, Manns MP, Wagner S. Growth characteristics and influence of antibiotics on rough/smooth phenotypic variants of Helicobacter pylori. Eur J Clin Microbiol Infect Dis 1999; 18:490-5. [PMID: 10482026 DOI: 10.1007/s100960050329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Helicobacter pylori shows a rather high variability of several biochemical markers including lipopolysaccharide structures. This study aimed to determine whether Helicobacter pylori has a potential for phenotypic variability and to describe its effects on bacterial pathogenesis. From colonies of three clinical strains of Helicobacter pylori with rough (R) colony morphology, spontaneous phenotypic variants with smooth (S) colony morphology were isolated that occurred with a frequency of 10(-2) to 10(-3), irrespective of growth conditions. R-variant bacteria produced exclusively low-molecular-mass lipopolysaccharide. They exhibited increased lysis in the presence of plain air. In contrast, the S variants produced low- and high-molecular-mass lipopolysaccharide and did not exhibit increased lysis in the presence of plain air. Cocultivation of bacterial cells with AGS stomach cancer cells revealed that R-variant bacteria but not S-variant bacteria effected an inhibition of high molecular-weight glycoprotein biosynthesis and secretion by the host cells. Skirrow supplement added as selective agent to liquid and/or solid media was tolerated to a similar extent among R- and S-variant bacteria, while all variants proved sensitive to metronidazole, amoxicillin and clarithromycin except for the R and S isolates of strain Hp57, which showed resistance to the latter compound. It was concluded that R- and S-variants of Helicobacter pylori may have distinct roles in pathogenesis; nevertheless, these bacteria may be isolated by traditional methods and eradicated by conventional anti-infective therapy.
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Affiliation(s)
- P A Bertram-Drogatz
- Institut für Allgemeine Pharmakologie, Medizinische Hochschule Hannover, Germany
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Abstract
Addressing how nurses become culturally competent is essential for knowledge development beyond why sociocultural understandings are important. This article reports participatory research conducted during intercultural immersion learning experiences of non-native nurses on an Indian reservation. Emphasizing collaborative relationships within unfamiliar social, political, and economic circumstances, and using Diekelmann's "concernful practices" as an organizing scheme, prompted participants to explicate practices that promote intercultural connecting. Suggesting integral shifts in value orientations with changes in cultural competence, the findings argue for attending to associations between those dynamics and potential for developing co-responsibility (with consumer groups) for advocating improved health and health care.
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Affiliation(s)
- K Kavanagh
- Department of Nursing, Northern Arizona University, Ganado, USA
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Wagner S, Enss ML, Cornberg M, Mix H, Schumann S, Kirchner G, Jähne J, Manns MP, Beil W. Morphological and molecular characterization of human gastric mucous cells in long-term primary culture. Pflugers Arch 1998; 436:871-81. [PMID: 9799401 DOI: 10.1007/s004240050717] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A primary cell culture of human gastric mucous cells was developed using enzymatic treatment of surgically obtained gastric mucosal specimens. Preferential attachment of gastric mucous cells during a preincubation step resulted in the enrichment of mucous cells [over 90% stained with periodic acid-Schiff (PAS) and mucin-type lectins] in the primary cell culture. Gastric mucous cells could be maintained in culture for 10 days. DNA synthesis peaked during the first 2 days in culture (8+/-1% bromodeoxyuridine-positive cells). During the entire culture period gastric mucous cells released high-molecular-weight glycoproteins into the medium, as determined by gel chromatography on a Sepharose CL-4B column and by metabolic labelling with [14C]-N-acetylglucosamine. Gastric mucin was verified by gas chromatographic analysis of the carbohydrate composition and fractionation of the void-volume fraction by density gradient centrifugation. Determination of the terminal glycosylation of the secreted glycoproteins by a lectin-ELISA revealed that there was a high quantity of alpha-l-fucose. Prostaglandin E2 significantly stimulated glycoprotein secretion during the entire cultivation period by 29-60%. Analysis of mucin-encoding MUC mRNA expression by reverse transcriptase polymerase chain reaction revealed that gastric mucous cells predominantly express MUC1 and MUC5AC, and to a lesser extent MUC6, which reflects the expression pattern obtained following analysis of biopsied samples of gastric mucosa. This primary cell culture model enables the regulation of mucin secretion and mucin gene expression in man to be investigated.
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Affiliation(s)
- S Wagner
- Dept. of Gastroenterology and Hepatology, Medizinische Hochschule Hannover, D-30623, Hannover, Germany.
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Beil W, Wagner S, Piller M, Heim HK, Sewing KF. Stimulation of pepsinogen release from chief cells by Helicobacter pylori: evidence for a role of calcium and calmodulin. Microb Pathog 1998; 25:181-7. [PMID: 9817821 DOI: 10.1006/mpat.1998.0225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To define the mechanisms by which Helicobacter pylori stimulates pepsinogen secretion, the in vitro release of pepsinogen was studied using a preparation of pig chief cell monolayers. Helicobacter pylori induced a time- and concentration-dependent release of pepsinogen into the medium, with about a three-fold increase in pepsinogen secretion over controls found after 45 min of incubation. 3x10(7) H. pylori produced 50% of the maximal response found at a H. pylori count of 2x10(8). The action of H. pylori did not depend on the presence of the vacuolating toxin (vacA) and the cytotoxin-associated protein (cagA). Dibutyryl-cAMP and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate also markedly stimulated pepsinogen secretion and enhanced the stimulatory effect of H. pylori. Helicobacter pylori-stimulated pepsinogen release was inhibited by lanthanum and the calmodulin antagonist W-7, but not by the L-type Ca2+ channel blocker nifedipine, TMB-8, an agent that blocks the release of Ca2+ from intracellular stores, the protein kinase C inhibitor staurosporine and the protein kinase A inhibitor H-8. It is suggested that H. pylori directly stimulates pepsinogen release from gastric chief cells and that this effect is mediated via the calcium/calmodulin messenger branch.
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Affiliation(s)
- W Beil
- Department of General Pharmacology, Medizinische Hochschule Hannover, Hannover, Germany
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Beil W, Birkholz C, Wagner S, Sewing KF. Helicobacter pylori fatty acid cis 9,10-methyleneoctadecanoic acid increases [Ca2+]i, activates protein kinase C and stimulates acid secretion in parietal cells. Prostaglandins Leukot Essent Fatty Acids 1998; 59:119-25. [PMID: 9774175 DOI: 10.1016/s0952-3278(98)90090-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The effect of the Helicobacter pylori (H. pylori) fatty acid cis 9,10-methyleneoctadecanoic acid (MOA) on gastric acid secretion was studied in isolated guinea-pig parietal cells. MOA (1 and 3 micromol/l) stimulated basal and enhanced histamine- and dibutyryl cyclic AMP-stimulated acid secretion in parietal cells. MOA increased intracellular free [Ca2+]i concentration in a concentration-dependent manner. The source of [Ca2+]i was extracellular as demonstrated by depletion of [Ca2+]i with EGTA. Furthermore, MOA caused activation of parietal cell protein kinase C (PKC). The effect of MOA upon PKC activation was [Ca2+]i-dependent but did not require phosphatidylserine as phospholipid co-factor. Similarly to the effect of diolein, MOA increased the stimulatory effect of phosphatidylserine at low [Ca2+]i concentrations. Treatment of parietal cells with MOA caused translocation of PKC from the cytosol to the membrane-associated cell fraction. We propose that MOA stimulates parietal cell acid secretion presumably by an increase of cytosolic free [Ca2+]i concentrations and PKC activation.
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Affiliation(s)
- W Beil
- Department of General Pharmacology, Hannover Medical School, Germany
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Enss ML, Heim HK, Wagner S, Beil W, Eisenblätter R, Sewing KF, Hedrich HJ. Effects of PGE2 and of different synthetic PGE derivatives on the glycosylation of pig gastric mucins. Prostaglandins Leukot Essent Fatty Acids 1998; 59:49-54. [PMID: 9758207 DOI: 10.1016/s0952-3278(98)90051-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The glycosylation of pig gastric mucins, discharged in response to prostaglandin (PG) E2 and to three synthetic PGE-derivatives (misoprostol, nocloprost, rioprostil) was compared. After a 20 h culture period in the absence or presence of 1 micromol/l of one of the PGs, mucins were isolated by gel chromatography and their glycosylation characterized by their linkage to a panel of lectins. For all tested PGs, a significantly increased lectin linkage to mucin glycoproteins of high molecular weight was detected; no significant effects were observed for low molecular weight glycoproteins. Within the stimulatory pattern, major effects were found for the linkage of peanut agglutinin and soybean agglutinin, suggesting predominant effects on the expression of galactose and N-acetyl-galactosamine. Only minor effects were found for sialic acid, mannose, N-acetyl-glucosamine and fucose expression, as evidenced by the linkage of Sambucus nigra agglutinin, Concanavalin A, Datura stramonium agglutinin and Ulex europaeus I agglutinin. All PGs exerted a similar stimulatory pattern. However, at the indicated concentration, misoprostol (281 +/- 36% of control) rendered a significantly higher overall effect than PGE2 (208 +/- 31%), whereas the increases induced by nocloprost (237 +/- 35%) and rioprostil (202 +/- 35%) were not significantly different from the PGE2 effects. These results, suggesting similar stimulatory effects of PGE2 and of the tested synthetic PGs on glycosylation of mucin oligosaccharides, discharged from mucous cells during an in vitro culture, may, at least in part, explain clinical findings that during an impairment of the endogenous PG synthesis, the tested synthetic PGs are effective exogenous substitutes for endogenous E-type prostaglandins and act as anti-ulcer drugs.
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Affiliation(s)
- M L Enss
- Department for Laboratory Animal Science, Medical School Hannover, Germany
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Kirchner GI, Franzke A, Buer J, Beil W, Probst-Kepper M, Wittke F, Overmann K, Lassmann S, Hoffmann R, Kirchner H, Ganser A, Atzpodien J. Pharmacokinetics of recombinant human interleukin-2 in advanced renal cell carcinoma patients following subcutaneous application. Br J Clin Pharmacol 1998; 46:5-10. [PMID: 9690943 PMCID: PMC1873983 DOI: 10.1046/j.1365-2125.1998.00036.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
AIMS The aim of the study was to investigate the pharmacokinetics of recombinant human interleukin-2 (rhIL-2) in patients with metastatic renal cell carcinoma following different subcutaneous (s.c.) administration regimens. METHODS RhIL-2 was administered subcutaneously to 10 patients according to two different dosing regimens: group A received 20 x 10(6) IU m(-2) once daily and group B 10 x 10(6) IU m(-2) twice daily (every 12 h). Additionally, in all patients the influence of soluble interleukin-2 receptor (sIL-2R) on the pharmacokinetics of rhIL-2 was investigated. RESULTS The mean area under the serum concentration-time curve to 24 h (AUC(0,24 h)) was 627 IU ml(-1) h in treatment group A and 1130 IU ml(-1) h (P=0.029) in treatment group B. In both study groups Cmax and AUC(0,12 h) were not significantly different. Seventy-two hours after the beginning of s.c. rhIL-2 therapy the sIL-2R increased significantly (P=0.016), and sIL-2R levels over 1200 pmol l(-1) seemed to reduce the AUC. CONCLUSIONS In patients with metastatic renal cell cancer administration of 20 x 10(6) IU m(-2) of rhIL-2 s.c. in two daily doses (10 x 10(6) IU m(-2) every 12 h) provides better bioavailability and is preferable to the single dose administration.
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Affiliation(s)
- G I Kirchner
- Institute for General Pharmacology, Medizinische Hochschule Hannover, Germany
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Beil W, Obst B, Wagner S, Sewing KF. The Helicobacter pylori fatty acid cis-9,10-methyleneoctadecanoic acid stimulates protein kinase C and increases DNA synthesis of gastric HM02 cells. Br J Cancer 1998; 77:1852-6. [PMID: 9667658 PMCID: PMC2150327 DOI: 10.1038/bjc.1998.308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Protein kinase C (PKC) has been implicated in the control of epithelial proliferative activity and in the process of malignant transformation. Helicobacter pylori (H.p.) infection is associated with increased gastric epithelial cell proliferation and has been linked with gastric carcinoma. In the present study, we report that the H.p. fatty acid cis-9,10-methyleneoctadecanoic acid (MOA) directly activates PKC (Ka 3.3 microM). The effect of MOA upon PKC activation was Ca2+ dependent but did not require phosphatidylserine as phospholipid cofactor. MOA increased the stimulatory effect of phosphatidylserine at low Ca2+ (1 microM) concentrations. These findings indicate that MOA interacts at the phospholipid- and the diacylglycerol-binding domain to elicit PKC activation. Treatment of gastric mucous cells HM02 caused translocation of PKC from the cytosol to the nuclear, mitochondrial and membrane fraction. Furthermore, MOA stimulated [3H]thymidine incorporation into the DNA of HM02 cells. Our results show that the H.p. fatty acid MOA activates PKC and increases DNA synthesis in gastric epithelial cells.
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Affiliation(s)
- W Beil
- Department of General Pharmacology, Hannover Medical School, Germany
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Wagner S, Beil W, Westermann J, Logan RP, Bock CT, Trautwein C, Bleck JS, Manns MP. Regulation of gastric epithelial cell growth by Helicobacter pylori: offdence for a major role of apoptosis. Gastroenterology 1997; 113:1836-47. [PMID: 9394723 DOI: 10.1016/s0016-5085(97)70003-9] [Citation(s) in RCA: 236] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND & AIMS Helicobacter pylori may affect the normal balance between gastric epithelial cell proliferation and epithelial cell death, thus interfering with the maintenance of gastric mucosal integrity. The aim of this study was to investigate the effect of H. pylori on cell growth, DNA synthesis, induction of apoptosis, and viability of human gastric epithelial cells in vitro. METHODS H. pylori was incubated with a differentiated human gastric cancer cell line for up to 72 hours, and the effects on cell numbers (cell counts and WST-1 assay), DNA synthesis (5-bromo-2'-deoxyuridine assay and [3H]thymidine incorporation), and DNA fragmentation (DNA fluorochrome staining, transmission electron microscopy, and histone enzyme-linked immunosorbent assay) were assessed. RESULTS Incubation of gastric epithelial cells with H. pylori led to a time- and concentration-dependent reduction of epithelial cell growth and a concomitant induction of DNA fragmentation. At high bacteria-cell ratios (> 100), inhibition of cell growth was associated with a reduction in DNA synthesis. Treatment of gastric cells with tumor necrosis factor alpha, a receptor-activating CD95/APO-1/Fas antibody, and interferon gamma markedly potentiated H. pylori-induced DNA fragmentation. CONCLUSIONS H. pylori affects gastric epithelial cell growth by direct induction of apoptosis and inhibition of DNA synthesis and indirectly by sensitization of epithelial cells for apoptosis induced by proinflammatory stimuli.
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Affiliation(s)
- S Wagner
- Department of Gastroenterology, Medizinische Hochschule Hannover, Germany. Wagner.Siegfried@MH-Hannover
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Mooren FC, Geada MM, Singh J, Stoll R, Beil W, Domschke W. Effects of extracellular Mg2+ concentration on intracellular signalling and acid secretion in rat gastric parietal cells. Biochim Biophys Acta 1997; 1358:279-88. [PMID: 9366259 DOI: 10.1016/s0167-4889(97)00062-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the present study, the effects of extracellular magnesium concentration ([Mg2+]ex) on stimulus-secretion coupling processes were investigated in rat gastric parietal cells in vitro. Extracellular magnesium reduction resulted in (1) an increase of basal intracellular free calcium concentration ([Ca2+]in), (2) an enhancement of both carbachol and thapsigargin-induced calcium responses, (3) an improved filling state of intracellular calcium stores, (4) an increase of both basal and carbachol-induced acid secretion, whereas intracellular adenosine 3',5'-cyclic monophosphate (cyclicAMP) levels and histamine stimulated acid secretion were not affected. The effects of high [Mg2+]ex were opposite to the described results, except that high [Mg2+]ex was able to decrease significantly histamine-stimulated cyclicAMP levels and acid secretion. These findings indicate a modulatory role of [Mg2+]ex on the intracellular signalling processes and acid secretory properties in rat parietal cells. These effects seemed to be mediated by regulating (1) calcium loading capacity of intracellular stores, (2) the permeability of the calcium influx pathway, and (3) the formation of cyclicAMP.
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Affiliation(s)
- F C Mooren
- Department of Medicine B, Westfälische Wilhelms-Universität, Münster, Germany
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Enss ML, Wagner S, Schmidt-Wittig U, Heim HK, Beil W, Hedrich HJ. Effects of PGE2 on amount and composition of high molecular weight glycoproteins released by human gastric mucous cells in primary culture. Prostaglandins Leukot Essent Fatty Acids 1997; 56:93-8. [PMID: 9051716 DOI: 10.1016/s0952-3278(97)90503-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The aim of this study was to determine effects of prostaglandin E2 (PGE2) on amount and composition of high molecular weight glycoproteins (HMG), released by human gastric mucous cells in primary culture. PGE2 stimulated the release of HMG, as evidenced by measurement of total carbohydrate and protein content, in a concentration-dependent manner. At the maximally tested concentration of 10(-5) mol/l, the increase amounted to 53% and 85%, over controls, for carbohydrate and protein, respectively. The stimulated release was accompanied by alterations of HMG glycosylation. As detected by lectin-ELISA, there was a relative decrease in N-acetyl glucosamine and an increase in mannose and galactose content. The sialic acid content increased in parallel to the total carbohydrate content. These results suggest that PGE2 plays a regulatory role in the synthesis and secretion of HMG by human gastric mucous cells.
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Affiliation(s)
- M L Enss
- Department for Laboratory Animal Science and Animal Facility, Medical School Hannover, Germany
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Odes HS, Reimer R, Muallem R, Schwenk M, Beil W, Sewing KF. Role of protein kinase C in duodenal mucosal bicarbonate secretion in the guinea pig. Pharmacology 1996; 53:60-5. [PMID: 8875602 DOI: 10.1159/000139415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Since duodenal bicarbonate secretion (DBS) is increased by m-cholinoceptor agonists, it was postulated that protein kinase C (PKC) has a role in this secretion. This premise was examined in guinea pigs, using 12-O-tetradecanoyl-phorbol 13-acetate (TPA) to stimulate bicarbonate production in the perfused duodenum in vivo, and to activate PKC in isolated duodenal enterocytes. TPA (10(-7) mol.kg-1) infused intravenously stimulated active DBS from basal values of 3.64 +/- 0.66 to 8.73 +/- 1.59 mumol.cm-1.10 min-1. This effect was completely blocked by verapamil (4 x 10(-7) mol.kg-1). PKC activity in duodenal enterocytes in the basal state was most abundant in the cytosolic fraction (2,221 +/- 444 U/mg protein) and very low in the particulate fraction (227 +/- 51 U/mg protein). TPA (10(-7) mol.kg-1) caused a time-dependent translocation of the cytosolic, lipid-dependent activity of PKC into the particulate fraction. The effect was maximal at 5 min incubation and was reversed by 30 min. In the particulate fraction, this activity was no longer lipid-dependent, but could be stimulated by Ca2+ alone. These data support the hypothesis that translocation of PKC may contribute to DBS.
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Affiliation(s)
- H S Odes
- Gastroenterology Institute, Soroka Medical Center, Beer Sheva, Israel
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Reimer R, Odes HS, Beil W, Schwenk M, Muallem R, Sewing KF. Bicarbonate secretion in the guinea pig duodenum: functional characterization of peptide hormone receptors in duodenal enterocytes. Pharmacology 1996; 52:339-46. [PMID: 8844783 DOI: 10.1159/000139400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To get information about the peptide hormone receptors involved in duodenal bicarbonate secretion (DBS) and their cellular location, we determined DBS and adenylate cyclase (AC) activity in response to hormones of the vasoactive intestinal polypeptide (VIP)/secretin family of peptides. DBS was determined in an isolated, perfused (24 mmol/1 NaHCO3) loop of the proximal duodenum in urethane- and indometacin-treated guinea pigs. AC stimulation was measured in isolated, homogenized duodenal enterocytes, the histological evaluation of which revealed their villous origin. VIP (10(-9) to 10(-7) mol x kg-1) dose-dependently increased DBS 3.5-fold (p < 0.01); this effect was completely inhibited by the VIP antagonist [D-p-Cl-Phe6,Leu17]VIP (10(-6) mol x kg-1). Glucagon (10(-8) to 10(-6) mol x kg-1) increased DBS 2.1-fold, while secretin (10(-9) to 10(-6) mol x kg-1) had no effect on DBS, but stimulated pancreatic bicarbonate secretion. VIP concentration-dependently increased AC activity 5.6-fold with an EC50 of 1.3 x 10(-9) mol/l. [D-p-Cl-Phe6,Leu17]VIP caused a rightward shift of the VIP concentration-response curve. A Schild plot analysis yielded a slope of 0.85 +/- 0.11, indicating competitive inhibition. While secretin also stimulated AC activity, although 1,000-fold less potent than VIP, glucagon was ineffective. These data indicate that specific VIP receptors, which mediate VIP-stimulated bicarbonate secretion, are present on villous enterocytes. Stimulation of AC by secretin seems to be of pharmacological relevance only and is consistent with the lack of effect of this hormone on DBS. Glucagon likely activates a second transmitter of bicarbonate secretion, or works independently of AC.
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Affiliation(s)
- R Reimer
- Institute of General Pharmacology, Medical School, Hannover, Germany
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Schöfl C, Rössig L, von zur Mühlen A, Beil W, Jähne J, Manns MP, Wagner S. Extracellular nucleotides increase cytosolic free calcium by activating P2u-receptors in single human gastric mucous cells. Biochem Biophys Res Commun 1995; 216:637-41. [PMID: 7488158 DOI: 10.1006/bbrc.1995.2669] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In single human gastric mucous cells extracellular ATP, ATP-gamma-S, ADP and UTP at micromolar concentrations caused a biphasic increase in [Ca2+]i. Consistent with a P2u-receptor the rank-order of potency was ATP > or = UTP > ATP-gamma-S > ADP, and cross-desensitization of the Ca2+ responses occurred between ATP and UTP. The initial transient peak in [Ca2+]i was resistant to extracellular Ca2+ depletion which demonstrates mobilization of internal Ca2+. By contrast, the sustained plateau phase required influx of external Ca2+. Ca2+ influx occurs most likely through a capacitative Ca2+ entry mechanism, which was shown to exist in these cells by experiments performed with thapsigargin. Thus, extracellular ATP and UTP activate a common P2u-receptor most likely coupled to the Ca(2+)-phosphatidylinositol signalling cascade. Extracellular nucleotides from various sources might be an important factor in the regulation of human gastric mucous cells.
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Affiliation(s)
- C Schöfl
- Department of Clinical Endocrinology, Medizinische Hochschule Hannover, Germany
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Beil W, Birkholz C, Sewing KF. Effects of flavonoids on parietal cell acid secretion, gastric mucosal prostaglandin production and Helicobacter pylori growth. Arzneimittelforschung 1995; 45:697-700. [PMID: 7646573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effect of the flavonoids flavone, flavanone and quercetin on parietal cell acid production, H+/K(+)-ATPase activity, gastric mucosal prostaglandin E2 biosynthesis and Helicobacter pylori growth was studied. All flavonoids inhibited acid production in isolated parietal cells in response to histamine and dibutyryl-cAMP stimulation (IC50 values between 26 and 139 mumol/l) and inhibited H+/K(+)-ATPase activity. Inhibition of H+/K(+)-ATPase activity was dependent on the ATP concentration. Fluorescence measurements showed that flavanone reacts with ATP. These findings indicate that the inhibitory action of flavonoids on H+/K(+)-ATPase activity is related to their ability to complex ATP. Flavone and flavanone (10 and 100 mumol/l) stimulated prostaglandin E2 production in isolated gastric mucosal cells. Furthermore, the compounds inhibited Helicobacter pylori growth in a concentration-dependent manner. From these finding it appears that flavonoids are a group of compounds which could have a therapeutic potential for treatment of gastrointestinal diseases associated with Helicobacter pylori infection.
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Affiliation(s)
- W Beil
- Institut für Allgemeine Pharmakologie, Medizinische Hochschule Hannover, Germany
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Abstract
The effects of various types of antiulcer agents against Helicobacter pylori F1-ATPase were studied. ATPase was released into the aqueous phase (i.e., solubilized) by sonication. The enzyme activity depended on Mg2+, but not Ca2+. The maximum activity occurred at an ATP/Mg2+ ratio of 1/5 and at pH 7.5. Mg(2+)-dependent ATPase activity was inhibited by sodium azide and the monovalent cations K+ and Na+, but not by oligomycin, dicyclohexylcarbodiimide, ouabain, or SCH 28080. The antiulcer agents ranitidine, pirenzepine, aluminum hydroxide, and sucralfate failed to influence H. pylori F1-ATPase. In contrast, bismuth subcitrate and the H+/K(+)-ATPase inhibitor omeprazole inhibited the enzyme. Inhibition was prevented and reversed by the mercaptan glutathione, indicating that both drugs interfere with sulfhydryl groups of the enzyme. The data suggest that bismuth subcitrate and omeprazole owe their antibacterial activity against H. pylori, at least in part, to inhibition of F1-ATPase, an enzyme involved in bacterial energy metabolism.
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Affiliation(s)
- W Beil
- Department of General Pharmacology, Medizinische Hochschule Hannover, Germany
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