In this theoretical article, the hypothesis is proposed that immunization against gastric helicobacter infection is mediated by CD4+ T-cell induced changes in mucus production. Vaccine development for the gastric pathogen Helicobacter pylori has encountered several problems. Resolving these problems is impeded by our lack of understanding of the mechanisms by ...

BACKGROUND & AIMS: The proton pump H(+),K(+)-adenosine triphosphatase (H(+),K(+)-ATPase) of parietal cells is the major humoral autoantigen in both human and experimental autoimmune gastritis (AIG) characterized by an inflammatory infiltrate in the gastric mucosa and loss of parietal cells. The aim of this study was to detect H(+),K(+)-ATPase-specific T cells ...

Variation among vascular plants in the initiation and patterning of leaves results in a diverse array of leaf shape, including the strap-like leaf of many grasses and the broad lamina of most eudicots. Recent findings highlight the importance of interactions between the shoot apical meristem (SAM) and developing leaf primordia ...

The mechanism by which Helicobacter pylori induces apoptosis remains unclear. In a previous study using biopsy samples, we found a significant correlation between the urease activity of an H. pylori strain and the apoptosis level induced by this strain. Therefore, in this study, we investigated whether urease and/or the ammonia ...

OBJECTIVES: Helicobacter pylori is an identified carcinogen for gastric cancer, however, the underlying mechanisms remain to be defined. In this review, we sought to elucidate the role of apoptosis in gastric carcinogenesis, to determine the influence of H. pylori infection on apoptosis, and finally to provide insights into the mechanisms ...

Two main pathogenic factors have been described in Helicobacter pylori strains: the cag pathogenicity island (cag PAI) and the vacuolating cytotoxin VacA. The cag PAI is comprised of approximately 40 open reading frames probably originating from another species. It encodes a type IV secretion system, i.e., an apparatus derived from ...

Interleukin (IL)-2 and IL-4 play a critical role in the regulation of the immune response. Yet both of the receptors for these cytokines have been found on nonhematopoietic cells, including human gastric carcinoma cell lines and tissue specimens. IL-4 causes G1 phase cell cycle arrest of gastric carcinoma; the effect ...

BACKGROUND AND AIM: A group of the proinflammatory and chemotactic cytokines (chemokines) has been considered as an important factor in the pathomechanism of different bacterial diseases, among them the common Helicobacter pylori infection. Experimental results obtained with gastric biopsy samples of H. pylori positive patients, and with H. pylori infected ...

The interleukin 1 receptor antagonist (IL1Ra) family of molecules now includes one secreted isoform (sIL1Ra) and three intracellular isoforms (icIL1Ra1, 2, and 3). Extensive evidence indicates that the sole biological function of sIL1Ra seems to be to competitively inhibit IL1 binding to cell-surface receptors. Although intracellular IL1Ra1 may be released ...

Helicobacter pylori (HP)-associated gastritis is characterized by an increased number of acute and chronic inflammatory cells secreting cytokines that contribute to maintain and expand the local inflammation. Locally induced IL-8 is believed to play a major role in the HP-associated acute inflammatory response. Factors/mechanisms that regulate IL-8 induction are, however, ...

Biological activity of bovine kappa-caseino glycomacropeptide (GMP) has received much attention in recent years. Research has focused on the ability of GMP to bind cholera and Escherichia coli enterotoxins, inhibit bacterial and viral adhesion, suppress gastric secretions, promote bifidobacterial growth and modulate immune system responses. Of these, protection against toxins, ...

The gastric inflammatory and immune response in Helicobacter pylori infection may be due to the effect of different H. pylori products on innate immune mechanisms. The aim of this study was to determine whether bacterial components could modulate cytokine production in vitro and thus contribute to Th1 polarization of the ...

Infection with Helicobacter pylori causes chronic active gastritis, which is characterized by neutrophils infiltrating the gastric epithelial layer and the underlying lamina propria as well as by T, B lymphocytes and macrophages accumulating in the lamina propria. In this study, the chemokine profile responsible for the recruitment of these inflammatory ...

Helicobacter pylori can colonize the gastric epithelium of humans, leading to the induction of an intense inflammatory response with the infiltration of mainly polymorphonuclear leucocytes (PMNs) and monocytes. These professional phagocytes appear to be a primary cause of the damage to surface epithelial layers, and probably contribute to the pathogenesis ...

Leflunomide (LFM) is a novel anti-inflammatory and immunosuppressive drug, and inhibits the growth of cytokine-stimulated lymphoid cells in vitro. The effect of LFM on haploid and diploid cells of Saccharomyces cerevisiae was investigated to elucidate the molecular mechanism of action of the drug. Using a halo assay, LFM was shown ...

Helicobacter pylori is now considered to be the main cause for most stomach diseases including ulcer, MALT lymphoma, adenocarcinoma and gastritis. The infection with this bacterium is chronic despite a local and systemic immune response towards it. Among the cellular infiltrate that arises during H. pylori-mediated gastritis, there is a ...

BACKGROUND/AIMS: To estimate the cytokine profile in Helicobacter pylori-positive patients with duodenal ulcers treated with omeprazole. METHODOLOGY: The subjects were 22 patients with endoscopically defined active duodenal ulcers and H. pylori infection treated with omeprazole for 3 months after initial 1-week triple therapy. Peripheral blood CD3+ CD4+ and CD8+ T ...

The common biologically cloned isolates of lactate dehydrogenase-elevating virus (LDV-P and LDV-vx) invariably cause a polyclonal activation of B cells in immunocompetent mice. It is recognized by an at least 10-fold increase in plasma IgG2a levels and the de novo formation of immune complexes that most likely consist of autoantibodies ...

Helicobacter pylori infection can induce polymorphonuclear leukocyte (PMNL) infiltration of the gastric mucosa, which characterizes acute chronic gastritis. The mechanisms underlying this process are poorly documented. The lack of an in vitro model has considerably impaired the study of transepithelial migration of PMNL induced by H. pylori. In the present ...

Gastric infections by Helicobacter pylori are characteristically associated with an intense inflammation and infiltration of mainly polymorphonuclear lymphocytes (PMNs) and monocytes. The inflammatory response by infiltrated immune cells appears to be a primary cause of the damage to surface epithelial layers and may eventually result in gastritis, peptic ulcer, gastric ...

The products released by Helicobacter pylori (H. pylori) in the gastric antral and duodenal mucosa may be involved in mucosal ulceration by stimulating the local formation of cytotoxic factors such as nitric oxide (NO), superoxide or peroxynitrite. The present study investigates the ability of purified H. pylori lipopolysaccharide (LPS) to ...

Helicobacter pylori causes a common chronic infection of humans that leads to epithelial cell damage. Studies have shown that apoptosis of the gastric epithelium is increased during infection and this response is associated with an expansion of gastric T-helper type 1 (Th1) cells. We report that gastric T cells contribute ...

Both polymorphonuclear cell infiltration and increased epithelial apoptosis are seen in gastric mucosa in the presence of Helicobacter pylori infection. This study examined the association between bacterial ability to stimulate an oxidative burst in neutrophils and epithelial apoptosis. Biopsy specimens were obtained from 15 patients to detect apoptotic cells by ...

Eicosanoids are arachidonic acid derivatives that include prostaglandins, thromboxanes, and leukotrienes. During the last three decades, it has become evident that these bioactive lipids play a pivotal role in gastric physiology. The goal of the present review is to describe their involvement in the normal regulation of gastric secretion and ...

Helicobacter pylori infection induces the appearance of inflammatory infiltrates, consisting mainly of neutrophils and monocytes, in the human gastric mucosa. A bacterial protein with neutrophil activating activity (HP-NAP) has been previously identified, but its role in infection and immune response is still largely unknown. Here, we show that vaccination of ...

Cutaneous T-cell lymphoma (CTCL) is a dynamic disease with several distinct components that make it unique from other lymphomas. The components of CTCL are reviewed to provide a background for understanding the role of pentostatin (Nipent; SuperGen, San Ramon, CA) in CTCL. In CTCL the malignant T cells mimic and ...

BACKGROUND: Helicobacter pylori causes gastritis and is strongly associated with gastroduodenal ulcer and gastric cancer. The bacterium is associated with an increased rate of epithelial proliferation, which can be reversed by eradication of the organism. The mechanism of this response is not known, but this epithelial proliferation is one of ...

BACKGROUND: Helicobacter pylori has been implicated in the pathogenesis of gastric cancer and malignant lymphoma. It is not known whether the bacterium stimulates cell proliferation directly or if apoptosis induced by H. pylori leads to a hyperproliferative response. AIM: To clarify the precise mechanism of H. pylori action on gastric ...

H. pylori infection almost invariably results in chronic gastritis, but only a proportion of patients develops severe destruction of epithelial glandular structure or peptic ulcer. To confirm the recent data obtained in testis and eye, showing that Fas ligand is involved in the phenomenon of "immune privilege," expression of Fas ...

Ten years have elapsed since the International Agency for Research on Cancer (IARC) evaluated the carcinogenicity of chromium and chromium compounds. Further studies performed during the last decade have provided further epidemiological, experimental and mechanistic data which support the IARC conclusions. A wealth of results indicate that, at variance with ...

Gastric epithelial turnover is a dynamic process. It is characterized by continuous cell proliferation, which is counterbalanced by cell loss. The biological principle that mediates the homeostasis of epithelium is programmed cell death, or apoptosis. Currently, several subtypes of apoptosis are distinguished, which are mediated by different mechanisms. Various subtypes ...

Apoptosis a programmed cell death, is an essential mechanism of eliminating damaged or aged cells and thus to maintain tissue integrity. There are two central pathways that lead to apoptosis: a) the positive induction by ligands (death factors) binding to plasma membrane receptors (death factor receptors) and b) negative induction ...

Fas-mediated gastric mucosal apoptosis is gaining attention as a cause of tissue damage due to Helicobacter pylori infection. We explored the effects of H. pylori directly, and the effects of the inflammatory environment established subsequent to H. pylori infection, on Fas-mediated apoptosis in a nontransformed gastric mucosal cell line (RGM-1). ...

Recent seroepidemiological and immunohistochemical studies have demonstrated an association between microbial infections and atherosclerosis. However, the mechanisms underlying this association are widely unknown. In the present study, arterial specimens obtained at autopsy after sudden death were analyzed concerning (1) the presence of Chlamydia pneumoniae, cytomegalovirus, herpes simplex virus, and Helicobacter ...

The present study aimed to investigate whether rebamipide, a novel antiulcer agent that has an oxygen radical scavenging activity, would inhibit lipid peroxidation, NF-kappaB activation, and IL-8 production by H. pylori. Human gastric epithelial cells (AGS and KATO III), treated with rebamipide or not were incubated in the absence or ...

Apoptosis, a programmed cell death, was ignored, just like Helicobacter pylori, only to reappear recently. However, the number of current publications dealing with apoptosis or H. pylori has increased exponentially. Although gastric epithelial apoptosis is a programmed physiological event in the superficial aspect of the mucosa and is important for ...

A large number of compounds are toxic, genotoxic, mutagenic, teratogenic and/or carcinogenic. The genotoxicity of four textile dyes commonly used in India namely Sulphur Red Brown 360 (SRB), Jade Green 2G (JG), Reactofix Turquoise Blue 5GFL (RTB) and Direct Scarlet 4BS (DS) was determined by Bacillus subtilis spore Rec assay, ...

Gastric mucosal injury by Helicobacter pylori has been suggested to be mediated by various cytokines induced by this organism. Nitric oxide (NO) is an important effector molecule involved in immune regulation and defence. To clarify the mechanisms by which H. pylori induces gastric mucosal cell injury, we examined whether H. ...

BACKGROUND: Increased nitric oxide (NO) synthase activity and enhanced apoptosis are features of gastric mucosa infected with Helicobacter pylori and a causative relation has been suggested. However, although NO can promote apoptosis, its actions vary with cell type. AIMS: To determine whether exogenous NO, derived from an NO donor, might ...

Helicobacter pylori colonizes the gastric epithelium of approximately 50% of the world's population and plays a causative role in the development of gastric and duodenal ulcers. H. pylori is phagocytosed by mononuclear phagocytes, but the internalized bacteria are not killed and the reasons for this host defense defect are unclear. ...

Xanthomatous changes may occur in meningiomas of different histological type, however their incidence in combination with histological features of atypical or anaplastic meningioma has not been previously documented. In this report we present clinicopathologic, immunohistochemical and ultrastructural studies in the surgical cases of two atypical and three anaplastic meningiomas exhibiting ...

BACKGROUND: Infection with Helicobacter pylori activates a proinflammatory gene program in human gastric epithelial cells and neutrophils and is associated with significant epithelial cell damage, including an increased level of apoptosis. We evaluated whether immune mediators produced by neutrophils could modulate gastric epithelial cell apoptosis in response to H. pylori ...

BACKGROUND AND AIM: Although mucosal alpha- and beta-chemokines are considered to be involved in the pathogenesis of Helicobacter pylori-associated gastritis, little is known how these chemokines are related to the ulcerogenesis in peptic ulcer patients. We examined the levels of interleukin (IL)-8 and macrophage inflammatory protein-1alpha (MIP-1alpha) in organ cultures ...

Helicobacter pylori infects an estimated 50% of the world population, however only a small proportion of individuals develop clinical symptoms of gastritis, peptic ulceration or gastric cancer. The variations in disease presentation may be due to differences in bacterial virulence and/or immune response to the pathogen. In the previous study ...

Lipopolysaccharides (LPS) are a family of toxic phosphorylated glycolipids in the outer membrane of Gram-negative bacteria, including Helicobacter pylori, and are composed of a lipid moiety (termed lipid A), a core oligosaccharide, and a polymeric O-specific polysaccharide chain. Compared with LPS of other bacteria, H. pylori LPS and lipid A ...

The recent demonstration in animal models that H. pylori alone may be capable of inducing intestinal-type gastric cancer, and that H. felis can accelerate gastrin-induced gastric neoplasia has stimulated research on examining the mechanisms of H. pylori-associated carcinogenesis in humans. Several mechanisms are currently under investigation, including the dysregulation of ...

We previously reported the induction of apoptotic DNA fragmentation by nonsteroidal anti-inflammatory drugs (NSAIDs) in cultured rat gastric cells, and indicated that prostaglandin-synthesis is only marginally involved in the apoptotic process. In the present study, we examined whether the generation of reactive oxygen species is critically involved in NSAID-induced apoptosis. ...

Research performed in the laboratory and the clinic over the past several years has added to our understanding of the mechanisms that are operative in protecting the epithelial lining of the stomach and duodenum from injury and ulceration, most frequently caused by necrotic agents in the lumen. The defensive mechanism ...

Helicobacter pylori (H. pylori) infection plays a role in the pathogenesis of peptic ulceration as well as active chronic gastritis. Possible mechanisms of H. pylori-induced mucosal injury include the generation of toxic monochloramine (NH2Cl) from oxidant (HOCl)--which is a product of activated neutrophils-and ammonia (NH3), which is a metabolite of ...

Helicobacter pylori lipopolysaccharide is a primary virulence factor responsible for eliciting acute mucosal inflammatory responses associated with H. pylori infection. In this study, we applied the animal model of H. pylori lipopolysaccharide-induced acute gastritis to assess the effect of antiulcer agent, ebrotidine, on the gastric mucosal inflammatory responses by analyzing ...