• Journal of Digestive Cancer Research
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• v.3 no.1
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• pp.21-25
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• 2015

Gastric neuroendocrine tumors (GNETs, also known as gastric carcinoids) are rare form of hormone-secreting neoplasms that present with varied clinical syndromes. There are four types of GNETs based on size, proliferation, localization, differentiation, and hormone production. Type I GNET is related to autoimmune atrophic gastritis and hypergastrinemia. Type II GNETs are related to multiple endocrine neoplasia (MEN)-1, Zollinger-Ellison syndrome and hypergastrinemia. Type 3 GNETs are not associated with any background pathology, and type 4 GNETs are poorly differentiated tumors. The most useful diagnostic and prognostic marker for gastrointestinal NETs is plasma chromogranin A (CgA) levels. Endoscopic ultrasound is the method of choice to determine tumor size and depth of infiltration. For optimal management, the type, biology, and stage of the tumor must be considered. Here, we provide a comprehensive and up-to-date review of GNETs.

• Journal of Digestive Cancer Research
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• v.10 no.1
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• pp.9-15
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• 2022

Proton pump inhibitors (PPIs), a potent gastric acid inhibitor, are widely used in gastric acid-related diseases such as gastroesophageal reflux disease and peptic ulcer, and are known as the most frequently used drugs worldwide. However, as the frequency of use increases, the number of cases of long-term PPI therapy without clear indications is increasing. Recently, there have been concerns about the risk of gastric cancer in patients with long-term PPI users. Potential mechanisms for the association between PPI and gastric cancer include enterochromaffin-like cell proliferation due to hypergastrinemia caused by gastric acid suppression, progression of atrophic gastritis, and corpus-predominant type through interaction with Helicobacter pylori (H. pylori) infection. Several epidemiologic studies showed controversial results on the issue, and it is difficult to prove a causal relationship between PPI and gastric cancer. Nevertheless, long-term PPI should be administered cautiously based on individual risk-benefit profile, specifically among those with history of H. pylori infection, in high-risk region of gastric cancer.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.100-100
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• 1997

To treat peptic ulcer diseases, many potent proton pump inhibitors have been developed for suppressing the gastric acid secretion in clinical patients. However, most of these agents have common irreversible mechanisms against H$\^$+/, K$\^$+/-ATPase which might be the cause of hypergastrinemia and ECL cell hyperplasia. Therefore, the development of new reversible inhibitors is prompted. In this study, we investigated the inhibitory mechanism of a newly synthesized proton pump inhibitor, YJA20379-8 using lyophilized hog gastric microsomes. YJA20379-8 inhibited K$\^$+/-stimulated H$\^$+/K$\^$+/-ATPase activity uncompetitively with respect to K$\^$+/, and in the other hand, showed competitive inhibitory pattern with ATP, respectively. From these data, we suggest that YJA20379-8 may be a proton pump inhibitor with a new inhibitory mechanism.

• Clinical Endoscopy
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• v.57 no.4
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• pp.417-423
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• 2024

Since the introduction of vonoprazan, a potassium-competitive acid blocker (P-CAB), it has been demonstrated to reversibly inhibit gastric acid secretion by engaging in potassium-competitive ionic binding to H⁺/K⁺-ATPase. In contrast, proton pump inhibitors (PPIs) achieve H⁺/K⁺-ATPase inhibition through covalent binding to cysteine residues of the proton pump. Reported cases have indicated an emerging trend of P-CAB-related gastropathies, similar to those associated with PPIs, as well as unique gastropathies specific to P-CAB use, such as the identification of web-like mucus. Pathologically, parietal cell profusions, which show a positively correlated with hypergastrinemia, have a higher incidence in P-CAB users compared to PPI users. Thus, this review aims to summarize the endoscopic and pathological findings reported to date concerning P-CAB-related gastric mucosal lesions. Additionally, it seeks to discuss the differences between the PPIs and P-CABs in terms of the formation and frequency of associated gastropathies. This review highlights the evident differences in the mechanism of action and potency of acid inhibition between P-CABs and PPIs, notably contributing to differences in the formation and frequency of associated gastropathies. It emphasizes the necessity to distinguish between P-CAB-related and PPI-related gastropathies in the clinical setting.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1315-1319
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• 2015

The fact that long-term use of proton pump inhibitors (PPIs) aggravates corpus atrophic gastritis in patients with Helicobacter pylori infection has been proven clinically and experimentally. Corpus atrophic gastritis is a known risk factor for gastric cancer. Therefore, gastric neoplasia might be associated with the long-term use of PPIs. One of the causes of worsening corpus atrophic gastritis, leading to the development of adenocarcinoma, might be bacterial overgrowth under conditions of hypochlorhydria. The production of potentially carcinogenic N-nitrosocompounds by nitrosating organisms under conditions of hypochlorhydria might be associated with carcinogenesis. Interactions between bile acids, pH, and H. pylori might also contribute to carcinogenicity, especially in patients with gastro-esophageal reflux disease (GERD). The concentration of soluble bile acids, which have bactericidal or chemorepellent properties toward H. pylori, in gastric contents is considerably higher in patients undergoing continuous PPI therapy than in healthy individuals with normal acid production. Under these circumstances, H. pylori might colonize the stomach body rather than the pyloric antrum. Hypergastrinemia induced by PPI administration might promote the development of gastric cancer. Because the main cause of corpus atrophic gastritis is H. pylori infection, and not PPI administration, H. pylori infection should be eradicated before starting long-term PPI therapy.

• Clinical Endoscopy
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• v.57 no.1
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• pp.65-72
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• 2024

Background/Aims: Multiple white and flat elevated lesions (MWFL) that develop from the gastric corpus to the fornix may be strongly associated with oral antacid intake. Therefore, this study aimed to determine the association between the occurrence of MWFL and oral proton pump inhibitor (PPI) intake and clarify the endoscopic and clinicopathological characteristics of MWFL. Methods: The study included 163 patients. The history of oral drug intake was collected, and serum gastrin levels and anti-Helicobacter pylori immunoglobulin G antibody titers were measured. Upper gastrointestinal endoscopy was performed. The primary study endpoint was the association between MWFL and oral PPI intake. Results: In the univariate analyses, MWFL were observed in 35 (49.3%) of 71 patients who received oral PPIs and 10 (10.9%) of 92 patients who did not receive oral PPIs. The occurrence of MWFL was significantly higher among patients who received PPIs than in those who did not (p<0.001). Moreover, the occurrence of MWFL was significantly higher in patients with hypergastrinemia (p=0.005). In the multivariate analyses, oral PPI intake was the only significant independent factor associated with the presence of MWFL (p=0.001; odds ratio, 5.78; 95% confidence interval, 2.06-16.2). Conclusions: Our findings suggest that oral PPI intake is associated with the presence of MWFL (UMINCTR 000030144).