ABSTRACT
H. pylori infection has been revealed to cause chronic gastric inflammation, which may progress to gastric ulcers and duodenal ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma as well as gastric adenocarcinoma. The mechanisms by which bacterial infection leads to gastric mucosal damage include the direct effects of virulence factors produced by H. pylori, such as cagA, vacA or urease, the propagation and perpetuation of inflammation, oxidative stress, and the induction of apoptosis in infected gastric epithelial cells. In the current review, the pathogenic mechanisms with their clinical relevance will be described.
Subject(s)
Adenocarcinoma , Apoptosis , Bacterial Infections , Duodenal Ulcer , Epithelial Cells , Helicobacter pylori , Helicobacter , Inflammation , Lymphoid Tissue , Lymphoma , Oxidative Stress , Stomach Ulcer , Urease , Virulence FactorsABSTRACT
BACKGROUND: The adhesion of H. pylori to the gastric epithelial cells may be an essential step for the pathophysiology of various H. pylori-induced gastrointestinal diseases. The purpose of this study was to investigate the ultrastructural relation of H. pylori and gastric epithelial cells in their adhesion. METHODS: Endoscopic biopsy of gastric antrum and body was performed from 15 patients (9 men, 6 women) with chronic gastritis and H. pylori infection. The specimens were processed for electron microscopy and observed with a transmission electron microscope (Hitachi H-600). RESULTS: On the basis of morphological appearances, the adhesions of H. pylori to the gastric epithelial cells were categorized into three types; filamentous connection, adhesion pedestals and membrane fusion. Coccoid and undetermined forms adhered mainly by the filamentous connection, whereas the bacillary forms adhered primarily by the adhesion pedestals and membrane fusion. CONCLUSION: Various types of adhesion were associated with H. pylori and gastric epithelium. Further studies are needed to evaluate the influence of different types of adhesion to the pathophysiology of H. pylori.
Subject(s)
Female , Humans , Male , Bacterial Adhesion , Endoscopy, Gastrointestinal , Gastritis/microbiology , Helicobacter Infections/microbiology , Helicobacter pylori/classification , Microscopy, Electron , Middle Aged , Stomach/microbiologyABSTRACT
Objective To investigate the inhibitory effect of DHA and its mechanism of apoptosis induced by DHA on human gastric cancer cell SGC-7901.Methods The survival rate of tumor cells was evaluated by MTT assay,cell morphology of apoptotic cell was observed with Hoechest 33258 staining.The contents of MDA and GSH were measured respectively by TBA and DTNB assay.Flow cytometry was used to detect the rate of apoptotic cell and intracellular variation of ROS level.Results After being treated with different concentrations of DHA,the survival rate of tumor cells was decreased in a dose-dependent manner and apoptosis was induced.The morphological characterizes of apoptotic cells were chromatin condensation and formation of apoptotic bodies.Intracellular MDA content was increased in the treated cells compared with control group,whereas GSH was decreased.After treated with 80 ?mol?L-1 DHA 5 h,flow cytometic analysis showed ROS peak and NAC could block the generation of ROS.Conclusion DHA can inhibit the growth of human gastric cancer cell SGC-7901 via inducing apoptosis.The increase of lipid peroxidation production and ROS may play an important role in apoptosis of the cells.
ABSTRACT
BACKGROUND: The purpose of this study was to investigate the ultrastructural relation of H. pylori and gastric epithelial cells in their adhesion. METHODS: Endoscopic biopsy of gastric antrum and body was performed from 15 patients (9 men, 6 women) with chronic gastritis. These specimens were processed and observed by transmission electron microscope (Hitachi H-600). RESULTS: On the basis of morphological appearances, the different types of adhesion of the organism with the epithelial cells were categorized as filamentous connection, adhesion pedestals, membrane fusion. Coccoid and intermediate forms were associated with filamentous connection whereas bacillary forms were associated with adhesion pedestals and membrane fusion. CONCLUSION: Various types of adhesion were associated with H. pylori and gastric epithelium. Further studies are needed to investigate biophysiologic influence to epithelial cells by ultrastructural relationship.(Korean J Med 60:16-21, 2001)
Subject(s)
Humans , Male , Biopsy , Epithelial Cells , Epithelium , Gastritis , Helicobacter pylori , Helicobacter , Membrane Fusion , Microscopy, Electron , Pyloric AntrumABSTRACT
OBJECTIVE:To investigate the effect of arsenic trioxide(As2O3) on the growth inhibition and apoptosis of gastric cancer cell SGC-7901 cultured in vitro in hypoxia condition.METHODS:The environment of hypoxia was established by using cobalt chloride.The gastric cancer cells were divided into three groups:normal group,hypoxia group and hypoxia combined with arsenic trioxide(0.5,1.0,2.0,5.0 and 10.0 ?mol?L-1)(HAT) group.The optical density of gastric cancer cell was determined by MTT method and inhibition rate was calculated at 24,48 and 72 h.The apoptosis rate of gastric caner cell was detected by using staining technique.RESULTS:After treated by 10.0 ?mol?L-1 arsenic trioxide for 24,48 and 72 h,the inhibition rates of SGC-7901 were 31.99%,55.98% and 72.40% for HAT group and 4.04%,6.65% and 8.11% for hypoxia groups,respectively;apoptosis rate were(42.88?1.72)%,(56.48?1.48)% and(65.52?1.00)% for HAT group and(2.08?0.28)%,(2.44?0.51)% and(2.76?0.67)% for hypoxia group,respectively.The difference between HAT group and hypoxia group was statistically significant(P