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1.
Phytomedicine ; 14 Suppl 6: 5-8, 2007.
Article in English | MEDLINE | ID: mdl-17188478

ABSTRACT

Helicobacter pylori specifically adheres to gastric host cells, mainly based on carbohydrate-mediated cell-cell interaction. The extract of Pelargonium sidoides roots (EPs) 7630), a South African herbal remedy, is currently used to treat acute bronchitis. EPs 7630 prevents bacteria from attaching to cell membranes. Therefore, the ability of EPs 7630 to interfere with H. pylori growth and adhesion to gastric epithelial cells (AGS cells) was tested in vitro. EPs 7630 inhibited H. pylori growth and with higher potency adhesion to gastric AGS cells. EPs 7630 (50 and 100 microg/ml) reduced bacterial count attached to AGS cells by 77% and 91%, respectively. The results suggest that the mode of action of EPs 7630 is mainly related to its anti-adhesive activity.


Subject(s)
Helicobacter pylori/drug effects , Pelargonium , Phytotherapy , Plant Extracts/pharmacology , Bacterial Adhesion/drug effects , Bacterial Adhesion/physiology , Dose-Response Relationship, Drug , Epithelial Cells/physiology , Gastric Mucosa/cytology , Gastritis/drug therapy , Helicobacter Infections/drug therapy , Helicobacter pylori/physiology , Humans , Plant Extracts/administration & dosage , Plant Extracts/therapeutic use , Plant Roots
2.
Lab Anim ; 39(2): 221-9, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15901366

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.


Subject(s)
Gastritis/microbiology , Helicobacter Infections/microbiology , Helicobacter pylori/pathogenicity , Serial Passage/methods , Animals , Colony Count, Microbial , Gerbillinae , Helicobacter Infections/pathology , Histological Techniques , Pyloric Antrum/pathology , Species Specificity
3.
Digestion ; 70(3): 178-86, 2004.
Article in English | MEDLINE | ID: mdl-15557763

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.


Subject(s)
Apoptosis/physiology , Helicobacter Infections/physiopathology , Helicobacter pylori/isolation & purification , Membrane Glycoproteins/physiology , Tumor Necrosis Factor-alpha/physiology , Apoptosis Regulatory Proteins , Cell Line , Cell Proliferation , Epithelial Cells/physiology , Fas Ligand Protein , Gastric Mucosa/physiopathology , Humans , Signal Transduction , TNF-Related Apoptosis-Inducing Ligand
4.
Appl Microbiol Biotechnol ; 64(4): 497-504, 2004 May.
Article in English | MEDLINE | ID: mdl-14593508

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.


Subject(s)
Bacillus/chemistry , Fatty Acids/analysis , Glycolipids/chemistry , Glycolipids/isolation & purification , Palmitic Acids/analysis , Animals , Anticarcinogenic Agents/pharmacology , Antineoplastic Agents/pharmacology , Bacillus/isolation & purification , Cell Division/drug effects , Cell Line, Tumor , DNA, Bacterial/chemistry , DNA, Bacterial/isolation & purification , DNA, Ribosomal/chemistry , DNA, Ribosomal/isolation & purification , Fatty Acids, Monounsaturated/metabolism , Glycolipids/metabolism , Glycolipids/pharmacology , Humans , Kinetics , Lipase/metabolism , Porifera/microbiology , Sequence Analysis, DNA , Surface Tension/drug effects , Water Microbiology
5.
Internist (Berl) ; 44(11): 1444-9, 2003 Nov.
Article in German | MEDLINE | ID: mdl-14689079

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.


Subject(s)
Drug Interactions , Drug Therapy/methods , Drug-Related Side Effects and Adverse Reactions/etiology , Pharmaceutical Preparations/metabolism , Pharmacokinetics , Practice Patterns, Physicians' , Treatment Failure , Humans
6.
Helicobacter ; 7(6): 367-77, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12485124

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.


Subject(s)
Apoptosis , Caspases/metabolism , Epithelial Cells/microbiology , Gastric Mucosa/microbiology , Helicobacter pylori/pathogenicity , BH3 Interacting Domain Death Agonist Protein , Carrier Proteins/metabolism , Cells, Cultured , Cytochrome c Group/metabolism , DNA Fragmentation , Enzyme Activation , Gastric Mucosa/cytology , Humans , Mitochondria/metabolism , Stomach Neoplasms , Tumor Cells, Cultured
7.
Gut ; 48(2): 157-62, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11156634

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.


Subject(s)
Enzyme Inhibitors/pharmacology , H(+)-K(+)-Exchanging ATPase/drug effects , Helicobacter pylori/physiology , Omeprazole/pharmacology , Parietal Cells, Gastric/drug effects , Animals , Cells, Cultured , H(+)-K(+)-Exchanging ATPase/physiology , Male , Parietal Cells, Gastric/physiology , Rats , Rats, Wistar , Stearic Acids/pharmacology , Swine
9.
Histochem Cell Biol ; 116(6): 483-93, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11810190

ABSTRACT

Scroll-rich, "mucosal" mast cells are the predominant human lung mast cell type. It has been proposed that these mast cells store tryptase but are mostly chymase deficient. We present a detailed immunolocalisation study of chymase and tryptase in lung specimens of eight patients. Using monoclonal antibody B7 in a conventional tissue processing method for light microscopy, chymase-positive mast cells were much fewer than tryptase-positive ones. However, they approached the number of tryptase-positive cells when optimised processing was used. Two different monoclonal antibodies, B7 and CC1, were used to visualise chymase in purified lung mast cells of two patients using ultrastructural immunogold labelling. Immunoabsorption controls demonstrated a reactivity of B7 with both tryptase and chymase, but indicated specificity of CC1 for chymase. On the ultrastructural level, all of more than 1,400 lung mast cells evaluated labelled for chymase. Reactivity was seen in cytoplasmic granules, cytoplasm and vesicles, but not elsewhere. Tryptase labelling using monoclonal antibody G3 was also present in all mast cells detected, and was retained in altered granules (=activated mast cells), where B7 labelling was sparse. The average labelling density was approximately sixfold higher than for chymase. In summary, chymase may be more abundant in human lung mast cells than hitherto thought.


Subject(s)
Lung/enzymology , Mast Cells/enzymology , Serine Endopeptidases/metabolism , Adult , Chymases , Cytoplasmic Granules/ultrastructure , Female , Humans , Lung/ultrastructure , Male , Mast Cells/ultrastructure , Microscopy, Immunoelectron , Middle Aged , Tryptases
11.
Dig Dis Sci ; 45(9): 1769-73, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11052318

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.


Subject(s)
Gastric Mucosa/metabolism , Glutathione/metabolism , Helicobacter pylori/physiology , Azoles/pharmacology , Free Radical Scavengers/pharmacology , Histamine H2 Antagonists/pharmacology , Humans , Isoindoles , Metalloporphyrins/pharmacology , Organoselenium Compounds/pharmacology , Proton Pump Inhibitors , Ranitidine/pharmacology , Tumor Cells, Cultured
12.
Gut ; 47(4): 481-6, 2000 Oct.
Article in English | MEDLINE | ID: mdl-10986207

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.


Subject(s)
Carrier Proteins/metabolism , Gastric Mucosa/metabolism , Leptin/metabolism , Receptors, Cell Surface , Biopsy , Cells, Cultured , Gastric Mucosa/pathology , Humans , Leptin/genetics , Protein Isoforms/genetics , Protein Isoforms/metabolism , RNA, Messenger/analysis , Receptors, Leptin , Reverse Transcriptase Polymerase Chain Reaction , Stomach Neoplasms/metabolism , Tumor Cells, Cultured
13.
Histol Histopathol ; 15(3): 937-46, 2000 07.
Article in English | MEDLINE | ID: mdl-10963136

ABSTRACT

This review provides a survey on mast cell heterogeneity, with aspects differing in humans and rodents or which are subject of conflicting evidence being discussed in greater detail. Mast cell subsets have been first defined in rats by their fixation and dye-binding properties, and detailed studies in humans and pigs reveal very similar observations. The dye-binding properties of rat mast cell subsets are causally related to the absence or presence of heparin in their granules. In humans, this relation has not been shown. Rodent mast cell subsets store different chymase-isoforms. In contrast, just a single chymase has been defined in humans, and mast cells are classified by the presence or relative absence of this chymase. Different investigators find quite different proportions of chymase-positive to chymase-negative mast cells. Tryptase(s) are found in most or every human mast cell, but in rodents, they have hitherto been essentially localised to mast cells in connective tissues. Human mast cell subsets may also be defined by their expression of receptors such as C5aR and possibly the beta-chemokine receptor CCR3; the CCR3 expression seems to be related to the human mast cell chymase expression. Ultrastructural studies are helpful to distinguish human mast cell subsets, and allow to distinguish between chronic and acute activation. The phenotypical characteristics may change in association with inflammation or other disease processes. Studies in humans and pigs show changed dye-binding and fixation properties of the granules. Experimental rodent infection models reveal similar changes of chymase isoform expression. Human lung mast cells have been reported to strongly upregulate their chymase content in pulmonary vascular disease. This line of evidence can explain some inconsistent information on mast cell heterogeneity and may help to understand the physiological role of mast cells.


Subject(s)
Mast Cells/physiology , Animals , Cell Differentiation , Chymases , Coloring Agents/metabolism , Endopeptidases/metabolism , Glycosaminoglycans/metabolism , Humans , Lymphocyte Subsets , Mast Cells/immunology , Mast Cells/metabolism , Mast Cells/ultrastructure , Mucous Membrane/cytology , Receptors, Immunologic , Serine Endopeptidases/metabolism , Staining and Labeling/methods
14.
Carcinogenesis ; 21(6): 1111-5, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10836997

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.


Subject(s)
DNA Damage , Helicobacter pylori/pathogenicity , Stomach/microbiology , Cell Cycle , DNA Replication , Epidermal Growth Factor/pharmacology , Epithelial Cells/metabolism , Epithelial Cells/microbiology , Gastric Mucosa/metabolism , Glutathione/metabolism , Humans , Poly Adenosine Diphosphate Ribose/metabolism , Reactive Oxygen Species , Stomach/cytology , Stomach/drug effects , Thymidine/pharmacology , Tumor Cells, Cultured
15.
J Clin Microbiol ; 38(6): 2215-8, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10834979

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.


Subject(s)
Antigens, Bacterial , Bacterial Proteins/biosynthesis , Cytotoxins/biosynthesis , Helicobacter pylori/pathogenicity , Mucins/metabolism , Stomach/microbiology , Acetylglucosamine/metabolism , Colony Count, Microbial , Glycoproteins/biosynthesis , Humans , Stomach/cytology , Tumor Cells, Cultured
16.
J Antibiot (Tokyo) ; 53(4): 329-36, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10866213

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.


Subject(s)
Anti-Bacterial Agents/isolation & purification , Anthraquinones/chemistry , Anthraquinones/isolation & purification , Anthraquinones/therapeutic use , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/therapeutic use , Fermentation , Gram-Positive Bacteria/drug effects , Humans , Microbial Sensitivity Tests , Molecular Structure , Stereoisomerism , Streptomyces , Structure-Activity Relationship , Tumor Cells, Cultured/drug effects
17.
Inflamm Res ; 49(4): 162-9, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10858016

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.


Subject(s)
Cytokines/physiology , Gene Expression Regulation/physiology , Intestinal Neoplasms/metabolism , Mucins/genetics , Blotting, Western , Gas Chromatography-Mass Spectrometry , Humans , Immunohistochemistry , Intestinal Neoplasms/genetics , Intestinal Neoplasms/pathology , Neoplasm Proteins/biosynthesis , Neoplasm Proteins/genetics , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , RNA, Neoplasm/biosynthesis , RNA, Neoplasm/genetics , Reverse Transcriptase Polymerase Chain Reaction , Tumor Cells, Cultured
18.
Eur J Cell Biol ; 78(11): 832-41, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10604660

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.


Subject(s)
Gastric Mucosa/metabolism , Gene Expression Regulation, Neoplastic , Mucins/genetics , Stomach Neoplasms/genetics , Alternative Splicing , Base Sequence , Biopsy , Blotting, Western , Epithelial Cells/metabolism , Gastric Mucosa/pathology , Humans , Immunohistochemistry , Mucins/metabolism , RNA, Messenger/analysis , Reverse Transcriptase Polymerase Chain Reaction , Stomach Neoplasms/metabolism , Tumor Cells, Cultured
19.
Eur J Clin Microbiol Infect Dis ; 18(7): 490-5, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10482026

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.


Subject(s)
Anti-Bacterial Agents/pharmacology , Helicobacter pylori/drug effects , Helicobacter pylori/growth & development , Helicobacter pylori/metabolism , Humans , Lipopolysaccharides/metabolism , Phenotype , Tumor Cells, Cultured
20.
ANS Adv Nurs Sci ; 21(3): 9-31, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10416854

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.


Subject(s)
Community Participation , Indians, North American , Transcultural Nursing/education , Communication , Female , Humans , Male , Nursing Research , Social Values , South Dakota
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