985 resultados para Ectopic gastric mucosa
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In this investigation, bromine-77 was produced with a medical cyclotron and imaged with gamma cameras. Br-77 emits a 240 kev photon with a half life of 56 hours. The C-Br bond is stronger than the C-I bond and bromine is not collected in the thyroid. Bromine can be used to label many organic molecules by methods analogous to radioiodination. The only North American source of Br-77 in the 70's and 80's was Los Alamos National Laboratory, but it discontinued production in 1989. In this method, a p,3n reaction on Br-77 produces Kr-77 which decays with a 1.2 hour half life to Br-77. A cyclotron generated 40 MeV proton beam is incident on a nearly saturated NaBr or LiBr solution contained in a copper or titanium target. A cooling chamber through which helium gas is flowed separates the solution from the cyclotron beam line. Helium gas is also flowed through the solution to extract Kr-77 gas. The mixture flows through a nitrogen trap where Kr-77 freezes and is allowed to decay to Br-77. Eight production runs were performed, three with a copper target and five with a titanium target with yields of 40, 104, 180, 679, 1080, 685, 762 and 118 uCi respectively. Gamma ray spectroscopy has shown the product to be very pure, however corrosion has been a major obstacle, causing the premature retirement of the copper target. Phantom and in-vivo rat nuclear images, and an autoradiograph in a rat are presented. The quality of the nuclear scans is reasonable and the autoradiograph reveals high isotope uptake in the renal parenchyma, a more moderate but uniform uptake in pulmonary and hepatic tissue, and low soft tissue uptake. There is no isotope uptake in the brain or the gastric mucosa. ^
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Helicobacter pylori infects the human gastric mucosa causing a chronic infection that is the primary risk factor for gastric cancer development. Recent studies demonstrate that H. pylori promotes tolerogenic dendritic cell (DC) development indicating that this bacterium evades the host immune response. However, the signaling pathways involved in modulating DC activation during infection remain unclear. Here, we report that H. pylori infection activated the signal transducer and activator of transcription 3 (STAT3) pathway in murine bone marrow-derived DCs (BMDCs) and splenic DCs isolated ex vivo. Isogenic cagA-, cagE-, vacA- and urease-mutants exhibited levels of phosphoSTAT3 that were comparable to in the wild-type (WT) parent strain. H. pylori-infected BMDCs produced increased immunosuppressive IL-10, which activated STAT3 in an autocrine/paracrine fashion. Neutralization of IL-10 prevented H. pylori-mediated STAT3 activation in both BMDCs and splenic DCs. In addition, anti-IL-10 treatment of infected H. pylori-BMDCs was associated with increased CD86 and MHC II expression and enhanced proinflammatory IL-1β cytokine secretion. Finally, increased CD86 and MHC II expression was detected in H. pylori-infected STAT3 knockout DCs when compared to WT controls. Together, these results demonstrate that H. pylori infection induces IL-10 secretion in DCs, which activates STAT3, thereby modulating DC maturation and reducing IL-1β secretion. These findings identify a host molecular mechanism by which H. pylori can manipulate the innate immune response to potentially favor chronic infection and promote carcinogenesis. © 2014 S. Karger AG, Basel.
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Prostaglandins such as prostaglandin E2 (PGE2) play a pivotal role in physiological and pathophysiological pathways in gastric mucosa. Little is known about the interrelation of the prostaglandin E (EP) receptors with the prostaglandin transporter OATP2A1 in the gastric mucosa and gastric carcinoma. Therefore, we first investigated the expression of OATP2A1 and EP4 in normal and carcinoma gastric mucosa. Different PGE2-mediated cellular pathways and mechanisms were investigated using human embryonic kidney cells (HEK293) and the human gastric carcinoma cell line AGS stably transfected with OATP2A1. Colocalization and expression of OATP2A1 and EP4 were detected in mucosa of normal gastric tissue and of gastric carcinomas. OATP2A1 reduced the PGE2-mediated cAMP production in HEK293 and AGS cells overexpressing EP4 and OATP2A1. The expression of OATP2A1 in AGS cells resulted in a reduction of [(3)H]-thymidine incorporation which was in line with a higher accumulation of AGS-OATP2A1 cells in S-phase of the cell cycle compared to control cells. In contrast, the expression of OATP2A1 in HEK293 cells had no influence on the distribution in the S-phase compared to control cells. OATP2A1 also diminished the PGE2-mediated expression of interleukin-8 mRNA (IL-8) and hypoxia-inducible-factor 1α (HIF1α) protein in AGS-OATP2A1 cells. The expression of OATP2A1 increased the sensitivity of AGS cells against irinotecan which led to reduced cell viability. Taken together, these data show that OATP2A1 influences PGE2-mediated cellular pathways. Therefore, OATP2A1 needs to be considered as a key determinant for the understanding of the physiology and pathophysiology of prostaglandins in healthy and tumorous gastric mucosa.
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An 8-yr-old male leopard (Panthera pardus) was presented with a 4-day history of lethargy, vomiting, and anorexia. Thoracic and abdominal radiographs revealed a soft-tissue mass cranial to the diaphragm and atypical appearance of the gastric fundus. Esophagoscopy revealed gastric mucosa in the lumen of the esophagus, which confirmed gastroesophageal intussusception. An exploratory celiotomy with manual reduction of the intussusception was performed. Reduction was verified by intraoperative esophagoscopy and gastroscopy. An incisional fundic gastropexy to the left abdominal wall was performed to reduce the chance of a recurrence of the intussusception. No postoperative complications related to the surgery were observed, and the animal resumed eating within 48 hr of surgery. A subsequent recurrence of clinical signs was not noted by the owner.
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Helicobacter pylori is one of the most common pathogenic bacterial infections, colonising an estimated half of all humans. It is associated with the development of serious gastroduodenal disease - including peptic ulcers, gastric lymphoma and acute chronic gastritis. Current recommended regimes are not wholly effective and patient compliance, side-effects and bacterial resistance can be problematic. Drug delivery to the site of residence in the gastric mucosa may improve efficacy of the current and emerging treatments. Gastric retentive delivery systems potentially allow increased penetration of the mucus layer and therefore increased drug concentration at the site of action. Proposed gastric retentive systems for the enhancement of local drug delivery include floating systems, expandable or swellable systems and bioadhesive systems. Generally, problems with these formulations are lack of specificity, limited to mucus turnover or failure to persist in the stomach. Gastric mucoadhesive systems are hailed as a promising technology to address this issue, penetrating the mucus layer and prolonging activity at the mucus-epithelial interface. This review appraises gastroretentive delivery strategies specifically with regard to their application as a delivery system to target Helicobacter. As drug-resistant strains emerge, the development of a vaccine to eradicate and prevent reinfection is an attractive proposition. Proposed prophylactic and therapeutic vaccines have been delivered using a number of mucosal routes using viral and non-viral vectors. The delivery form, inclusion of adjuvants, and delivery regime will influence the immune response generated. © 2005 Bentham Science Publishers Ltd.
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This study concerns the nature of nitric oxide synthase (NOS) and the role of nitric oxide (NO) in the rat gastrointestinal tract. The major objectives were (i) to characterise NOS isoforms in the gastric glandular mucosa, (ii) to localise NOS isoforms in the rat gastric glandular mucosa, (iii) to investigate the role of NO in carbachol-stimulated gastric mucus secretion, (iv) to investigate the nature of NOS and small intestine. Immunoblotting was performed using polyclonal antisera raised against two peptides found in the rat brain NOS sequence and commercial monoclonal antibodies directed against neuronal and endothelial isoforms of NOS. A160kDa band was detected in brain and gastric mucosal samples with antibodies and antisera directed against neuronal NOS sequences, and a 140kDa band was detected in gastric mucosal samples using an anti-endothelial NOS antibody. An intense 160kDa neuronal NOS band was detected in a high-density fraction of gastric mucosal cells separated on a Percoll gradient. Detection of neuronal NOS by a carboxyl-terminal antiserum in samples of brain, but not of gastric mucosa, could be blocked by the peptide (20g/ml) against which the antibody was raised. After affinity purification, recognition of gastric mucosal NOS was blocked by peptide. Particulate neuronal NOS was found in the brain by immunoblotting while 94% of gastric mucosal enzyme was soluble. Gastric mucosal endothelial NOS was 95% particulate. 95% of NOS activity in the gastric mucosa was due to neuronal NOS. Paraformaldehyde- and acetone-fixed gastric mucosal sections were subject to immunocytochemistry using the above antibodies. Neuronal NOS was localised to the surface mucosal epithelial cells while endothelial NOS was associated with microvessels at the base of the mucosa and to larger vessels in the submucosa. Intragastric administration of carbachol or 16, 16-dimethyl prostaglandin E2 increased the thickness of the rat gastric mucus layer. The NOS inhibitor NG-nitro-L-arginine methyl ester dose-dependently, and selectively, prevented the stimulatory effect of carbachol. Ca2+-independent NOS activity in rat ileal, jejunal and colonic muscle was increased after LPS induction. Ca2+-dependent activity was not affected. Distribution of inducible NOS protein paralleled Ca2+ -independent activity. LPS treatment did not affect the content of neuronal NOS in colonic muscle.
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Nitric oxide is a free-radical gas which can exert both protective and damaging effects. The objectives of the thesis were: (i) to investigate arginine metabolism in isolated rat gastric mucosal cells, (ii) to investigate the role of NO in the induction of ornithine decarboxylase in the rat gastric mucosa damaged by hypertonic saline in vivo, (iii) to expose primary cultures of guinea-pig gastric mucosal cells to oxidative challenge and an NO donor, and to investigate the response in terms of heat shock protein 72 (HSP 72) induction, and (iv) to investigate the induction of iNOS and the role of potential modulators of activity in gastric cell lines. Isolated rat gastric mucosal cells converted exogenous arginine to ornithine and citrulline. This metabolism of arginine was not affected by a range of NO synthase inhibitors, but was reduced by the arginase inhibitors NG-hydroxy-L-arginine and L-ornithine. Thus, the predominant pathway of arginine metabolism involves arginase and ornithine transcarbamoylase, not NO synthase. Pretreatment of rats with NG-nitro-L-arginine promoted activation of ornithine decarboxylase after intragastric hypertonic saline, but did not increase acid phosphatase release (damage). NO may therefore restrict activation of ornithine decarboxylase in response to damage. Exposure of primary cultures of guinea-pig gastric mucosal cells to S-nitroso-N-acetyl-penicillamine (SNAP) caused a concentration dependent induction of HSP 72, which was inhibited by an NO scavenger and blockade of transcription. The effect of SNAP was enhanced by decreasing the intracellular reduced thiol content with diethyl maleate, which itself also induced HSP 72 formation. Substantial amounts of NO may induce defensive responses in cells. Induction of iNOS was not detected in HGT-1 or AGS cells exposed to cytokines. Conclusions An arginase pathway may restrict availability of arginine for NO synthase in gastric mucosa or may be present to supply ornithine for polyamine synthesis. NO may modulate the response to damage of the stomach epithelium in vivo. Exogenous NO may induce a defensive response in gastric mucosal cells.
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This study was undertaken to increase knowledge of the mechanisms of inter- and intracellular signalling in the gastrointestinal tract. Specific aims were: to use cell lines to elucidate factors affecting growth of gastric cells, to investigate the distribution and aspects of function of isoforms of protein kinase C in a gastric cell line and in the rat gastrointestinal tract and to determine the presence and regulation of nitric oxide synthase in gastrointestinal tissues from the rat and in cell lines. The gastric cancer cell line HGT-1 was used to investigate control of growth. Increases in cell number were found to be dependent on the seeding density of the cells. In cells plated at low density insulin, epidermal growth factor and gastrin all increased cell number. Gastrin produced a bell-shaped dose response curve with a maximum activity at 5nM. No effect of gastrin was apparent in cells plated at high density. α and β isoforms of protein kinase C were found, by immunoblotting procedures, to be widespread in the gastrointestinal tract of the rat, but protein kinase Cε was confined to the gastric mucosa and gastrointestinal smooth muscle. HGT-1 cells contained protein kinase C α and ε but β or γ were not detected. Preincubation of HGT-1 cells for 24h with 1μM phorbol-12,13-dibutyrate down-regulated protein kinase C α but not ε. The inhibition by the activator of protein kinase C, 12-O-tetradecanoylphorbol 13-acetate (TPA) of the histamine-stimulated increase in cAMP in HGT-1 cells was down regulated by phorbol-12,13-dibutyrate. Inhibition of histamine-stimulation of adenylate cyclase by TPA was Ca2+-dependent and inhibited by the addition of an antibody to protein kinase C α. A role for protein kinase C α in modulating the effect of histamine on adenylate cyclase in HGT-1 cells is suggested. No nitric oxide synthase activity was detected in the gastrointestinal cell lines HGT-l, MKN-45 or CaCo-2. Ca2+-dependent nitric oxide synthase activity was observed in the gastric mucosa and the gastrointestinal smooth muscle from stomach to colon. The gastric: mucosal enzyme was soluble and showed half-maximal activity at 400nM Ca2+. Pretreatment of rats with endotoxin (3mg/kg body weight) induced nitric oxide synthase activity in both jejunal, ileal and colonic mucosa and muscle. A major portion of the induced activity in ileal and colonic mucosa was Ca2+-independent. Nitric oxide synthase activity in a high-density fraction of gastric mucosal cells was inhibited in a dose-dependent fashion by L-nitroarginine, NG-monomethyl-L-arginine, trifluoperazine and L-canavanine (in descending order of potency). Preincubation with okadaic acid and addition of ATPlMg2+ to the homogenisation buffer inhibited enzyme activity, which implies that phosphorylation inhibits gastric mucosal nitric oxide synthase.
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Antecedentes: El cáncer gástrico se diagnostica tardíamente. Sólo en países como Corea y Japón existen políticas de tamizaje, que se justificarían en cualquier país con alta prevalencia de cáncer gástrico como Colombia o Chile. El análisis del pepsinógeno sérico se ha propuesto para el diagnóstico de lesiones premalignas y malignas gástricas, por lo cual se pretende revisar sistemáticamente en la literatura el valor diagnóstico del cociente pepsinógeno I/II como marcador de lesiones premalignas y malignas gástricas. Metodología: Se revisó la literatura hasta septiembre del 2016 con palabras claves lesiones malignas, premalignas gástricas y pepsinógeno en las bases de datos PubMed, OVID, EMBASE, EBSCO, LILACS, OPENGRAY y Dialnet, artículos de prueba diagnóstica que evaluaran el cociente pepsinógeno I/II en relación con los hallazgos histológicos. Resultados: Se incluyeron 21 artículos conun total de 20601 pacientes, que demuestranuna sensibilidad entre13.7% - 91.2%, una especificidad entre 38.5% - 100%, un Valor Predictivo Positivo entre 6.3% - 100% y un Valor Predictivo Negativo entre 33.3% - 98.8%del cociente pepsinógeno I/II en relación con el diagnósticode lesiones premalignas y malignas gástricas. Conclusiones: Los valores del cociente pepsinógeno I/II disminuidos se relacionan con la presencia delesiones premalignas y malignas gástricas.Dado que tiene mejor especificidad que sensibilidad, en cuanto prueba para tamizaje, sería útil para la selección de pacientes que se beneficiaríande la EVDA. Se requieren más estudios de prueba diagnóstica para validar un punto de corte específico que pueda ser utilizado como valor estándar.
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Background: Subtotal esophagectomy and gastric pull-up with cervical anastomosis is the main treatment for advanced achalasia. This surgical technique has been associated to esophagitis and also Barrett`s epithelium following esophagectomy. Aim: To analyze late clinical, endoscopic, and pathologic findings in the esophageal stump (ES) mucosa after subtotal esophagectomy in patients treated for advanced chagasic achalasia. Methods: 101 patients submitted to esophagectomy and cervical gastroplasty were followed-up prospectively for a mean of 10.5 +/- 8.8 years. All patients underwent clinical, endoscopic and histopathological evaluation every 2 years. Gastric acid secretion was also assessed. Results: The incidence of esophagitis in the esophageal stump (45.9% at 1 year; 71.9% at 5 years, and 70.0% at 10 years follow-up); gastritis in the transposed stomach (20.4% at 1 year, 31.0% at 5 years, and 40.0% at 10 or more years follow-up), and the occurrence of ectopic columnar metaplasia and Barrett`s Esophagus in the ES (none until 1 year; 10.9% between 1 and 5 years; 29.5% between 5 and 10 years; and 57.5% at 10 or more years follow-up), all rose over time. Gastric acid secretion returns to its preoperative values 4 years postoperatively. Esophageal stump cancer was detected in the setting of chronic esophagitis in five patients: three squamous cell carcinomas and two adenocarcinomas. Conclusion: (1) Esophagitis and Barrett`s esophagus in the esophageal stump rose over time. (2) These mucosal alterations and the development of squamous cell carcinoma and adenocarcinoma are probably due to exposure to duodenogastric reflux, and progressively higher acid output in the transposed stomach.
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PURPOSE:To evaluate morphological changes of the gastric stump and not resected stomach mucosa after the completion of truncal vagotomy.METHODS:Eighty male Wistar rats were divided into four groups: CT, TV, RY and RYTV. In CT group, abdominal viscera were manipulated and the abdominal cavity was closed, in TV vagal trunks were isolated and sectioned, in RY a partial Roux-en-Y gastrectomy was performed and in RYTV the vagal trunks were sectioned and a partial Roux-en-Y gastrectomy was performed. At the 54th week after surgery, the rats were euthanized. The findings were submitted to histological analyses.RESULTS:None macroscopic or histological alterations in groups TV and CT was observed. Specimens from RY and RYTV groups did not show alterations in the gastric stump mucosa. At the jejunal side of the gastroenterostomy we found shallow ulcerative lesions always single, well-defined and with variable diameter 3 to 6 mm, six times in the RY group and none in the RYTV group (RY>RYTV, p=0.008). Neoplastic or preneoplastic lesions were not diagnosed in all groups.CONCLUSION:Truncal vagotomy is a safe and non-carcinogenic method in not resected and partially resected stomach.
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Gastro-oesophageal Reflux Disease (GORD), is generally caused by excess gastric reflux back to the oesophagus where damage to the mucosa results in injury. GORD is a very common disease in western countries, more than a quarter of western people are suffering from this disease and there is a trend that the percentage population in eastern countries who are diagnosed as GORD is increasing. GORD and its complications damage the quality of life and can lead to serious oesophageal diseases including Barrett’s disease and oesophageal carcinoma. Sodium alginate dissolved in water forms a viscous liquid and can coat on oesophageal mucosa for a period of time. In this study the ability of the liquid alginate to adhere to the oesophageal mucosa was investigated and the factors that affect this retention were examined. The potential of this liquid alginate as a drug delivery vehicle to extend the duration of contact with the oesophageal mucosa was confirmed by this study. The capacity of an alginate coating to retard acid and pepsin diffusion, the two main aggressive factors in gastric reflux, was investigated. A significant reduction in acid and pepsin diffusion by alginate gel layer was demonstrated in this project, indicating that alginate has great potential to protect against damage caused by acidic reflux. A novel method was introduced using an independent score system to assess the protection of oesophageal tissue by a coating of liquid alginate using microscopy as a technique. This technique demonstrated that alginate can protect the oesophageal epithelial tissue from the damage caused by gastric acid and pepsin. Many techniques were used in this study. The experimental results suggested that liquid sodium alginate is a very promising candidate in treating local oesophageal diseases through forming a coating on the oesophageal mucosal surface, retarding the diffusion of components of gastric refluxate and thus reducing the contact of these noxious factors with the epithelium and minimising injury.
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BACKGROUND: Early gastric cancer (EGC) is defined as adenocarcinoma limited to the mucosa or submucosa regardless of lymph node involvement. Local EGC recurrence rates have been described ill Lip to 6% of cases. OBJECTIVES: To evaluate predictive factors for incomplete resection and local recurrence of EGC treated by endoscopic mucosal resection (EMR) that was followed up for at least one year. METHODS: From June 1994 to December 2005, 46 patients with EGC underwent EMR. Possible predictive factors for incomplete endoscopic resection and local recurrence were identified by medical chart analysis. Demographic, endoscopic and histopathological data were retrospectively evaluated. EMR was considered complete or incomplete. Patients from the complete resection group were divided into subgroups (with and without local EGC recurrence). RESULTS: Complete resection was possible in 36 cases (76.6%). Predictive factors for incomplete resection were turnout location (P=0.035), histological type (P=0.021), lesion size (P=0.022) and number of resected fragments (P=0.013). On multivariate analysis, undifferentiated histological type (OR 0.8; 95% Cl 0.036 to 0.897) and number of resected fragments (OR 7.34; 95% Cl 1.266 to 42.629) were independent predictive factors for incomplete resection. In the complete resection group, a larger lesion size was associated with a higher the number of resected fragments (P=0.018). Local recurrence occurred in nine cases (25%). Use of the cap technique was the only predictive factor for local recurrence in five of seven cases (71.4%) (P=0.006). CONCLUSIONS: A larger lesion size was associated with a higher number of resected fragments. Undifferentiated adenocarcinoma and piecemeal resection were predictive factors for incomplete resection. Technique type was a predictive factor for local EGC recurrence.
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Objective: To assess the association between the depth of trophoblastic penetration into the tubal wall with serum concentrations of vascular endothelial growth factor (VEGF) and beta-hCG and to assess its predictive value. Design: Prospective study. Setting: Tertiary care university hospital. Patient(s): Thirty patients with ampullary pregnancy undergoing salpingectomy were analyzed. Intervention(s): Trophoblastic invasion was histologically classified as stage I when limited to the tubal mucosa, stage II when extending to the muscle layer, and stage III in the case of complete tubal wall infiltration. Main Outcome Measure(s): The relation between depth of trophoblastic infiltration into the tubal wall with VEGF and beta-hCG serum concentrations on the day of surgery. Result(s): An association between the depth of trophoblastic invasion and maternal serum concentrations of VEGF and beta-hCG was observed. VEGF levels of 297.2 pg/mL showed 100.0% sensitivity and 90.0% specificity for stage I, and levels of 440.1 pg/mL showed 81.8% sensitivity and 88.8% specificity for stage III. Beta-hCG levels of 2590.0 mIU/mL showed 88.9% sensitivity and 80.0% specificity for stage I, and levels of 10,827.0 mUI/mL showed 72.7% sensitivity and 88.9% specificity for stage III. Conclusion(s): Maternal serum VEGF and beta-hCG concentrations are associated with depth of trophoblastic penetration into the tubal wall. (Fertil Steril (R) 2010;94:1595-600. (C) 2010 by American Society for Reproductive Medicine.)
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Background: There are now several lines of evidence to suggest that protein synthesis and translation factors are involved in the regulation of cell proliferation and cancer development. Aims: To investigate gene expression patterns of eukaryotic releasing factor 3 (eRF3) in gastric cancer. Methods: RNA was prepared from 25 gastric tumour biopsies and adjacent non-neoplastic mucosa. Real time TaqMan reverse transcription polymerase chain reaction (RT-PCR) was performed to measure the relative gene expression levels. DNA was isolated from tumour and normal tissues and gene dosage was determined by a quantitative real time PCR using SYBR Green dye. Results: Different histological types of gastric tumours were analysed and nine of the 25 tumours revealed eRF3/GSPT1 overexpression; moreover, eight of the 12 intestinal type carcinomas analysed overexpressed the gene, whereas eRF3/GSPT1 was overexpressed in only one of the 10 diffuse type carcinomas (Kruskal-Wallis Test; p , 0.05). No correlation was found between ploidy and transcript expression levels of eRF3/GSPT1. Overexpression of eRF3/GSPT1 was not associated with increased translation rates because the upregulation of eRF3/GSPT1 did not correlate with increased eRF1 levels. Conclusions: Overexpression of eRF3/GSPT1 in intestinal type gastric tumours may lead to an increase in the translation efficiency of specific oncogenic transcripts. Alternatively, eRF3/GSPT1 may be involved in tumorigenesis as a result of its non-translational roles, namely (dis)regulating the cell cycle, apoptosis, or transcription.