Role of the antioxidant pathway in the healing of peptic ulcers induced by ischemia-reperfusion in male and female rats treated with Eugenia punicifolia.

Ischaemia and reperfusion (I/R)-induced gastrointestinal disorders are caused by free radicals, resulting in organ damage and functional disarrangement. This study aimed to investigate the healing effects of hydroalcoholic extracts from the leaves of Eugenia punicifolia (Kunth) DC. (HEEP) in male and female Wistar rats with I/R-induced peptic injuries, and the role of antioxidants in improving this response. After I/R-induced gastric and duodenal injuries, male and female [intact (INT) and ovariectomized (OVZ)] rats were orally treated with HEEP for 6 days. Biochemical analysis was used to determine the catalase (CAT), superoxide dismutase (SOD), and myeloperoxidase (MPO) activities, as well as malondialdehyde and reduced glutathione levels, to measure the gastric and duodenal healing process. Six days of HEEP treatment significantly decreased the I/R-induced gastric [male (73.68%), INT (52.83%), and OVZ (43.13%)] and duodenal damage [male (57.03%), INT (56.04%), and OVZ (54.83%)] in all groups. In OVZ rats, the healing effect of HEEP occurred because of the increased activity of SOD (2x) and CAT (1.16x) in the gastric mucosa. In the duodenal mucosa of INT rats, the extract reduced MPO (20.83%) activity. The 6-day HEEP treatment improved the healing of I/R-induced peptic ulcer injury, with the system acting differently in males and females. The antioxidant system is an important component of the HEEP activity during post-I/R mucosal recovery. This result revealed the importance of antioxidant compounds in minimizing the severity of I/R-related events.

Selective Inhibition of Helicobacter pylori Carbonic Anhydrases by Carvacrol and Thymol Could Impair Biofilm Production and the Release of Outer Membrane Vesicles.

Helicobacter pylori, a Gram-negative neutrophilic pathogen, is the cause of chronic gastritis, peptic ulcers, and gastric cancer in humans. Current therapeutic regimens suffer from an emerging bacterial resistance rate and poor patience compliance. To improve the discovery of compounds targeting bacterial alternative enzymes or essential pathways such as carbonic anhydrases (CAs), we assessed the anti-H. pylori activity of thymol and carvacrol in terms of CA inhibition, isoform selectivity, growth impairment, biofilm production, and release of associated outer membrane vesicles-eDNA. The microbiological results were correlated by the evaluation in vitro of H. pylori CA inhibition, in silico analysis of the structural requirements to display such isoform selectivity, and the assessment of their limited toxicity against three probiotic species with respect to amoxicillin. Carvacrol and thymol could thus be considered as new lead compounds as alternative H. pylori CA inhibitors or to be used in association with current drugs for the management of H. pylori infection and limiting the spread of antibiotic resistance.

The role of nitric oxide in peptic ulcer: a narrative review.

Peptic ulcer refers to the inflammatory response and necrotic lesions of the mucosa under the action of various pathogenic factors, which goes deeply into the mucosal muscle layer and often occurs to the gastrointestinal mucosa related to gastric acid secretion, among which the stomach and duodenum are the most common. The clinical manifestations include slow onset, prolonged course and weekly upper abdominal pain. Nitric oxide (NO) is an intracellular and intercellular signaling molecule that plays an important role in many physiological and pathological processes. Studies have found that a small amount of NO produced in vivo plays a role in many physiological homeostasis, such as regulating blood pressure, platelet aggregation, nitrogenization of hemoglobin, and regulating proliferation and differentiation of stem cells. However, under the action of some cytokines and oxidative stress, intracellular NO synthase will catalyze the synthesis of large amounts of NO and participate in the inflammatory response, causing beneficial or harmful effect on the body. Numerous basic studies have focused on the relationship between NO and peptic ulcer. The purpose of this review is to summarize the role of NO in peptic ulcer and its possible mechanism.

A Review of the Role of Flavonoids in Peptic Ulcer (2010-2020).

Peptic ulcers are characterized by erosions on the mucosa of the gastrointestinal tract that may reach the muscle layer. Their etiology is multifactorial and occurs when the balance between offensive and protective factors of the mucosa is disturbed. Peptic ulcers represent a global health problem, affecting millions of people worldwide and showing high rates of recurrence. Helicobacter pylori infection and the use of non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most important predisposing factors for the development of peptic ulcers. Therefore, new approaches to complementary treatments are needed to prevent the development of ulcers and their recurrence. Natural products such as medicinal plants and their isolated compounds have been widely used in experimental models of peptic ulcers. Flavonoids are among the molecules of greatest interest in biological assays due to their anti-inflammatory and antioxidant properties. The present study is a literature review of flavonoids that have been reported to show peptic ulcer activity in experimental models. Studies published from January 2010 to January 2020 were selected from reference databases. This review refers to a collection of flavonoids with antiulcer activity in vivo and in vitro models.

Helicobacter pylori Virulence Factor Cytotoxin-Associated Gene A (CagA)-Mediated Gastric Pathogenicity.

Helicobacter pylori causes persistent infection in the gastric epithelium of more than half of the world's population, leading to the development of severe complications such as peptic ulcer diseases, gastric cancer, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Several virulence factors, including cytotoxin-associated gene A (CagA), which is translocated into the gastric epithelium via the type 4 secretory system (T4SS), have been indicated to play a vital role in disease development. Although infection with strains harboring the East Asian type of CagA possessing the EPIYA-A, -B, and -D sequences has been found to potentiate cell proliferation and disease pathogenicity, the exact mechanism of CagA involvement in disease severity still remains to be elucidated. Therefore, we discuss the possible role of CagA in gastric pathogenicity.

Caspase-4: A Therapeutic Target for Peptic Ulcer Disease.

Peptic ulcers are caused by the interaction between bacterial and host factors. This study demonstrates enhanced expression of caspase-4 in peptic ulcer patient biopsies, indicating that pyroptosis and noncanonical inflammasome activity may be processes involved in peptic ulcer disease. We show that primary murine macrophages infected with Helicobacter pylori upregulate caspase-11 (the ortholog of human caspase-4), activate caspase-1, and secrete IL-1ß. We demonstrate that misoprostol (a stable PGE1 analogue) decreased IL-1ß secretion and delayed lethality in vivo in a murine peritonitis model. PGE2 was shown to inhibit caspase-11-driven pyroptosis and IL-1ß secretion in macrophages. Overall, we provide evidence for a pathological role of caspase-4/11 in peptic ulcer disease and propose that targeting caspase-4 or inhibiting pyroptosis may have therapeutic potential in the management of peptic ulcers.

High expression of Helicobacter pylori VapD in both the intracellular environment and biopsies from gastric patients with severity.

Helicobacter pylori is a Gram-negative bacterium that causes chronic atrophic gastritis and peptic ulcers and it has been associated with the development of gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT). One of the more remarkable characteristics of H. pylori is its ability to survive in the hostile environment of the stomach. H. pylori regulates the expression of specific sets of genes allowing it to survive high acidity levels and nutrient scarcity. In the present study, we determined the expression of virulence associated protein D (VapD) of H. pylori inside adenocarcinoma gastric (AGS) cells and in gastric biopsies. Using qRT-PCR, VapD expression was quantified in intracellular H. pylori-AGS cell cultures at different time points and in gastric mucosa biopsies from patients suffering from chronic atrophic gastritis, follicular gastritis, peptic ulcers, gastritis precancerous intestinal metaplasia and adenocarcinoma. Our results show that vapD of H. pylori presented high transcription levels inside AGS cells, which increased up to two-fold above basal values across all assays over time. Inside AGS cells, H. pylori acquired a coccoid form that is metabolically active in expressing VapD as a protection mechanism, thereby maintaining its permanence in a viable non-cultivable state. VapD of H. pylori was expressed in all gastric biopsies, however, higher expression levels (p = 0.029) were observed in gastric antrum biopsies from patients with follicular gastritis. The highest VapD expression levels were found in both antrum and corpus gastric biopsies from older patients (>57 years old). We observed that VapD in H. pylori is a protein that is only produced in response to interactions with eukaryotic cells. Our results suggest that VapD contributes to the persistence of H. pylori inside the gastric epithelial cells, protecting the microorganism from the intracellular environment, reducing its growth rate, enabling long-term infection and treatment resistance.

Role of levan extracted from bacterial honey isolates in curing peptic ulcer: In vivo.

Peptic ulcer is one of the worldwide diseases where 10% of adults are affected by peptic ulcers at least once in their lifetime. The goal of this study was to evaluate the effect of levan in treating peptic ulcer. The bacterial honey isolates called Bacillus sp. levan was utilized. Levan was chemically characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), 1H and 13C NMR analysis. Levan was used to treat gastric ulcers induced in rats by oral administration of 5 mL/kg ethanol. Microscopic examination of stomach sections indicated that treatment with 200 mg/kg levan effectively healed the ulcers. Levan had no antimicrobial activity against a common cause of ulcers such as Helicobacter pylori bacteria. Rather, we proposed that the high adhesion (manifested as a protective coating) and prebiotic activity of levan may account for the observed beneficial effects. The immunohistochemical examination showed that levan led to a noticeable Bacillus sp. levan reduction in NF-κB in the upper gastric mucosa. The results concluded that the role of levan was more protective rather than preventive and suggested that levan could play a fundamental role in solving the peptic ulcer problems.

Trachyspermum ammi (L.) Sprague, superb essential oil and its major components on peptic ulcers: in vivo combined in silico studies.

BACKGROUND: Trachyspermum ammi (L.) Sprague is used for treating gastrointestinal disorders. Several studies indicated gastric antiulcer activity of T. ammi extract, yet the effect of its essential oil has not been studied on. OBJECTIVES: The present study evaluates chemical composition of T. ammi essential oil and anti-peptic ulcer effect of the essential oil as well as its three major components in ethanol induced-gastric ulcers in rats. METHODS: Primarily chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC/MS). Rats received the essential oil (500, 250, 125, 62.5, 31.25 mg/kg), thymol (30, 100 mg/kg), para-cymene (100, 150 mg/kg) and gamma-terpinene (100, 150 mg/kg) using gavage tube along with ethanol 80%. Finally, dissected stomachs were assessed both macroscopically and microscopically to evaluate anti-ulcerative effect of the essential oil and the pure compounds. Moreover, molecular docking was utilized to explore the interactive behavior of the main components with active site residues of H+/K+ ATPase. RESULTS: Analysis of the essential oil indicated that para-cymene (37.18%), gamma-terpinene (35.36%) and thymol (20.51%) are the main components. Administration of different doses of the essential oil noticeably diminished the number of peptic ulcers in a dose-dependent manner. Among the main components, thymol was more potent than para-cymene and gamma-terpinene. Administration of the essential oil (500 mg/kg) and thymol (100 mg/kg) observed maximum inhibition percentage (98.58% and 79.37%, respectively). Molecular docking study provides the evidence of thymol ability to inhibit H+/K+ ATPase. CONCLUSIONS: The findings revealed that T. ammi essential oil can be applied to treat gastric ulcer as a natural agent. Graphical abstract.

The influence of the Chuyou Yuyang granule on the Toll-like receptor/nuclear factor-κB signal pathway in Helicobacter pylori-positive peptic ulcer patients.

BACKGROUND: The cure rate of Helicobacter pylori (HP)-positive peptic ulcer has appeared to downward trend, and the resistance of the ulcer relapse has become a hot issue. METHODS: Hematoxylin and eosin staining was used to detect the repair of the damaged tissues in patients after treatment with the Chuyou Yuyang granule (CYYY). Elisa was used to analyze the expression of cytokine interleukin 18 (IL-18) and tumor necrosis factor α (TNF-α) in the patients' serum. Western blot analysis was used to explore the mechanism of the CYYY. Reverse-transcription polymerase chain reaction (RT-PCR) was used to detect the expression of microRNA-155a (miR-155a) and miR-146a in the blood of the patients and to confirm whether CYYY could cure peptic ulcer through regulation of miR-155a and miR-146a. RESULTS: The damaged gastric mucosal tissues of ulcer patients were significantly repaired by treating with CYYY. The pro-inflammatory cytokine IL18 and TNF-α were notably repressed after treating with CYYY. In addition, CYYY played a key role in regulation of the Toll-like receptor (TLR4)/nuclear factor-κB (NF-κB) signal pathway and the expression of miR-155a and miR-146a. CONCLUSION: CYYY was a highly effective therapeutic method for peptic ulcer patients by inhibiting the activation of the TLR4/NF-κB signal pathway and suppressing the expression of miR-155a and miR-146a.

Byrsonima intermedia A. Juss partitions promote gastroprotection against peptic ulcers and improve healing through antioxidant and anti-inflammatory activities.

Byrsonima intermedia is a species of bush popularly used to treat gastrointestinal disorders, such as gastric ulcers, gastritis, and diarrhea. Previous studies have revealed that the methanolic crude extract of B. intermedia leaves has gastroprotective and healing properties. In this new study, we specifically investigated two purified partitions, ethyl acetate (EtOAc) and water (AcoAq), obtained from the crude extract to characterize the antiulcer effects of these two partitions and the mechanisms of action of this medicinal plant. The healing effects of these partitions on the gastric and duodenal mucosa were assessed after ischemia-reperfusion (I/R) or acetic acid-induced injury. The involvement of tumor necrosis factor-alpha (TNF-alpha), interleukin 1ß (IL-1ß), interleukin 10 (IL-10), and myeloperoxidase (MPO) activity and glutathione (GSH) levels were determined. The antibacterial activity against Helicobacter pylori was evaluated using microdilution methods. The phytochemical analysis of AcoAq revealed a predominance of oligomeric proanthocyanidins and galloyl quinic esters, whereas EtOAc was found to contain concentrated flavonoids. Both partitions led to a significant reduction in gastric lesions, but AcoAq was more effective than EtOAc with regard to anti-Helicobacter pylori activity in addition to protecting the gastric mucosa against ethanol, non-steroidal anti-inflammatory drugs (NSAIDs) and duodenal mucosal damage induced by cysteamine. Additionally, both partitions were associated with a significant increase in gastric and duodenal healing and increased gastric mucosal GSH content after damage induced by acetic acid. On the other hand, after 6 days of treatment, EtOAc was more effective than AcoAq in ameliorating gastric damage upon initiation of the gastric I/R, which was accompanied by a significant reduction in the activity of gastric mucosal MPO, IL 1-ß and TNF-alpha, as well as an elevation in IL-10 and GSH content. These results demonstrate that the oligomeric proanthocyanidins and galloyl quinic esters present in AcoAq were more effective in the prevention of gastric and duodenal ulcers due to the antioxidant effects of these compounds, whereas the flavonoids present in EtOAc were more effective due to their anti-inflammatory activity on the gastric and duodenal tissue. All these results confirm that the rich phytochemical diversity of B. intermedia contributes to the pharmacological actions of this medicinal plant on the gastrointestinal tract in addition to its activity against H. pylori.

Effects of Tegoprazan, a Novel Potassium-Competitive Acid Blocker, on Rat Models of Gastric Acid-Related Disease.

Tegoprazan, a novel potassium-competitive acid blocker (P-CAB), is a next-generation therapeutics developed for the treatment of acid-related gastrointestinal diseases such as gastroesophageal reflux disease (GERD) and peptic ulcers. In the present study, the in vitro and in vivo pharmacological properties of tegoprazan were compared with those of esomeprazole, a representative proton pump inhibitor. In vitro enzyme assays were performed using ion-leaky vesicles containing gastric H+/K+-ATPases isolated from pigs. The in vivo efficacies of tegoprazan were evaluated in rat models of GERD and peptic ulcer. Tegoprazan inhibited the activity of porcine H+/K+-ATPase with an IC50 value of 0.53 µM in a reversible manner, whereas esomeprazole showed weak and irreversible inhibition with an IC50 value of 42.52 µM. In a GERD model, tegoprazan showed dose-dependent efficacy in inhibiting esophageal injury and gastric acid secretion with an ED50 of 2.0 mg/kg, which was 15-fold more potent than that of esomeprazole. In peptic ulcer models, tegoprazan exhibited superior antiulcer activity compared with esomeprazole. The ED50 of tegoprazan in the naproxen-, ethanol-, and water-immersion restraint stress-induced peptic ulcer models were 0.1, 1.4, and 0.1 mg/kg, respectively. In the acetic acid-induced peptic ulcer model, the curative ratio of tegoprazan at 10 mg/kg was higher than that of esomeprazole at 30 mg/kg (44.2% vs. 32.7%, respectively), after 5 days of repeated oral administration. Thus, tegoprazan is a novel P-CAB that shows potent and reversible inhibition of gastric H+/K+-ATPase and may provide stronger efficacy compared with previous proton pump inhibitors.

Gastroprotective effect of memantine in indomethacin-induced peptic ulcer in rats, a possible role for potassium channels.

AIMS: Memantine is a commonly used drug in treating Alzheimer disease. In the current work, we aimed to evaluate the gastro-protective effect of memantine in indomethacin-induced peptic ulcer in rats. MAIN METHODS: Peptic ulcer induced by indomethacin and memantine administered either alone or in combination with glibenclamide or nitric oxide synthase (NOS) inhibitor. Ulcer index done and malondialdehyde (MDA), superoxide dismutase (SOD), total nitrites, expression of tumor necrosis factor-α (TNF-α) and expression of nuclear factor kappa B (NF-κB) were measured in gastric mucosa. KEY FINDINGS: Memantine reduced ulcer index, reduced MDA, increased SOD, increased total nitrites and reduced expression of both TNF-α and NF-κB. Glibenclamide and not NOS inhibitor abolished the gastroprotective effect of memantine. SIGNIFICANCE: Memantine was protective against indomethacin-induced peptic ulcer in rats mostly by affecting potassium channels, antioxidative stress and anti-inflammatory actions.

Floating Drug Delivery Systems: An Emerging Trend for the Treatment of Peptic Ulcer.

Floating drug delivery system (FDDS) is the main approach to prolonging the gastric residence time in the stomach in which the bilayer floating tablet has the main role. It is more suitable for the treatment of local infections such as peptic ulcer, gastritis, Zollinger-Ellision syndrome, indigestion, and other local infections related to the gastrointestinal tract and also used for systemic applications. FDDS provides protection for those drugs which are acid labile and have a short half-life. It also improves bioavailability, reduces drug waste, and enhances the residence time of drugs. Nowadays, various technologies are being used for the development of FDDS. Novel drug delivery systems incorporation into bilayer floating tablets have also broadened the role of FDDS. Polymers have the main role in the development of FDDS, which serve as carriers for the drug and determine the gastric retention time and drug protection. FDDS is also an easy, cheap, and more convenient method for dual drug delivery of drugs.

A Novel Role of Irbesartan in Gastroprotection against Indomethacin-Induced Gastric Injury in Rats: Targeting DDAH/ADMA and EGFR/ERK Signaling.

The advent of angiotensin II type 1 receptor blockers (ARBs) as intriguing gastroprotective candidates and the superior pharmacokinetics and pharmacodynamics displayed by irbesartan compared to many other ARBs raised the interest to investigate its gastroprotective potential in a rat model of gastric injury. Irbesartan (50 mg/Kg) was orally administered to male Wistar rats once daily for 14 days; thereafter gastric injury was induced by indomethacin (60 mg/Kg, p.o). Irbesartan reduced gastric ulcer index, gastric acidity, and ameliorated indomethacin-induced gastric mucosal apoptotic and inflammatory aberrations, as demonstrated by hampering caspase-3, prostaglandin E2 and tumor necrosis factor-alpha levels and cyclooxygenase-2 mRNA expression. This ARB increased mucosal dimethylarginine dimethylaminohydrolase-1 (DDAH-1) gene expression and decreased elevated levels of matrix metalloproteinase-9, asymmetric dimethylarginine (ADMA), epidermal growth factor receptor (EGFR) mRNA and phosphorylated extracellular signal-regulated kinase 1 and 2 (pERK1/2). Histopathological evaluation corroborated biochemical findings. Overall efficacy of irbesartan was comparable to ranitidine, the widely used H2 receptor blocker. In conclusion, irbesartan exerts significant gastroprotection against indomethacin-induced mucosal damage via acid-inhibitory, anti-inflammatory, anti-apoptotic and extracellular matrix remodeling mechanisms that are probably mediated, at least partly, by down-regulating DDAH/ADMA and EGFR/ERK1/2 signaling.

Up-regulated Th17 cell function is associated with increased peptic ulcer disease in Helicobacter pylori-infection.

BACKGROUND: During Helicobacter pylori (H. pylori) infection CD4+ T cells in the gastric lamina propria are hyporesponsive and polarized by Th1/Th17 cell responses controlled by Treg cells. The objective of this study was to determine the number of Th17 cells in gastric mucosa of patients with gastritis and peptic ulcer and determined the relationship between main virulence factor of H. pylori and Th17 cells. METHODS AND MATERIALS: A total of 89 H. pylori-infected gastritis patients, 63 H. pylori-infected peptic ulcer patients and 48 H. pylori-negative non-ulcer dysplasia patients were enrolled in this study. The number of Th17 was determined by immunohistochemistry. IL-8 and IL-17A expressions were determined by real-time polymerase chain reaction (qPCR). Also, the grade of chronic and active inflammation was investigated for involvement according to the density of neutrophils and mononuclear in gastric mucosal crypts, from one to all crypts. RESULTS: The number of Th17 cells and the expression of IL-8 and IL-17A in infected patients were significantly higher than uninfected subjects. The number of Th17 cells and the expression of IL-8 and IL-17A in infected patients with peptic ulcer were significantly higher than patients with gastritis. Additionally, the numbers of Th17 cells as well as the expression of IL-8 and IL-17A were positively correlated with the degree of H. pylori density in infected patients with peptic ulcer, while this correlation was negative in infected patients with gastritis. The numbers of Th17 cells as well as the expression of IL-8 and IL-17A were positively correlated with the degree of chronic inflammation. CONCLUSION: The predominant Th17 cell responses may play a role in the pathogenesis of peptic ulcers disease in infected patients.

Association of TNF-α but not IL-1ß levels with the presence of Helicobacter pylori infection increased the risk of peptic ulcer development.

Peptic ulcer is a lesion in the mucosa of the digestive tract affecting many people all around the world. Recent investigations have indicated that produced inflammatory cytokines such as TNF-α and IL-1ß in response to gastric infection by Helicobacter pylori play an important role in the development of peptic ulcer. With regard to the significance of these cytokines in peptic ulcer development and the high prevalence of this disease in the developing countries, this study aimed to investigate the association of TNF-α and IL-1ß with peptic ulcer in the presence of H. pylori. This case-control study enrolled 61 patients with peptic ulcer disease (PUD) as cases and 59 people without peptic ulcer (NPUD) as controls. Blood samples and endoscopic biopsies were collected. H. pylori infection was confirmed by using rapid urease test (RUT), specific IgG measurement and histopathological examination. Then, IL-1ß and TNF-α levels were evaluated using enzyme linked immunosorbent assay (ELISA). The seropositivity of H. pylori was 62.5% in the studied population, while by considering RUT and histopathological examination along with specific-IgG antibody, H. pylori infection decreased to 56.7%. In addition, H. pylori infection was significantly (OR = 0.37; 95% CI = 0.17-0.82; P = .02) associated with peptic ulcer development. The TNF-α level in PUD and infected H. pylori subjects was significantly higher than that of control and un-infected H. pylori individuals. However, no significant difference of IL1ß level was observed between PUD and control groups as well as between H. pylori infected and un-infected individuals. Interestingly, IL-1ß level in PUD patients without H. pylori infection was significantly higher than infected ones. Moreover, a significant correlation between specific-IgG antibody with TNF-α level was observed. Taken together, our results showed that increased level of TNF-α could probably play pivotal role in pathogenesis of peptic ulcer in the presence of H. pylori infection. These findings also highlighted the importance of IL-1ß in the absence of H. pylori infection in peptic ulcer development.

New insight into the control of peptic ulcer by targeting the histamine H2 receptor.

Peptic ulcer disease is one of the major challenges in public health globally and new evidence shows that it can be controlled by targeting the histamine H2 receptor (H2 R). Recently, a number of H2 R antagonists have been synthesized and used to block the action of histamine on the parietal cells in the stomach and decrease the acid production. In this study, we modeled the H2 R by homology modeling using the 3-D crystal structure and this model was validated based on free energy and amino acid residues present in the allowed regions of a Ramachandran plot. We used this 3-D model for screening of highly potent drugs using molecular docking. We found cimetidine, cimetex, and famotidine as the most potent drugs based on the binding affinity of drug-protein interactions. We also generated a cellular network for H2 R that could be useful for better understanding of cellular mechanism and drug targets. These findings provide a new insight into the development of suitable, specific, and effective anti-ulcer drugs for a most effective treatment of ulcerous diseases.

Stereoselective and nonstereoselective pharmacokinetics of rabeprazole - an overview.

1. Proton pump inhibitors have been extensively used for the treatment of ailments due to increased gastric acid secretion such as peptic ulcers, gastroesophageal reflux disease, etc. 2. There are several approved drugs in the proton pump inhibitor class with the latest entries representing single enantiomer drugs of the previously approved racemic drugs. 3. Despite having a high degree of structural resemblance, rabeprazole, was shown to possess some unique differentiation from other drugs in the class. One of the key distinguishing features of rabeprazole was related to the lesser involvement of polymorphic metabolism in its pharmacokinetic disposition. 4. The review was aimed to provide pharmacokinetic data of rabeprazole from several clinical studies including drug-drug interaction studies where rabeprazole was either a perpetrator drug or victim drug. 5. Additional perspectives on therapy considerations due to the unique metabolic disposition of rabeprazole including the possible issues related to chirality were provided.

Effect of EGF on Bax, Bcl-2 and Fas expression in ulcerous disease and N87 cell line.

BACKGROUND: To evaluate the effect of epithelial growth factor (EGF) in primary culture of ulcer patients and N87 cell line on expressions of apoptotic genes. METHODS: Ulcer patients who attended Gastroenterology Clinic of Mersin University Medical Faculty were included in this study. Three different doses of EGF were applied to the primary culture of biopsy samples from ulcer patients and gastric cancer cell-line (ATCC-NCI-N87) . The expression levels of Bax, Bcl-2 and Fas genes were measured with quantitative real-time PCR (qRT-PCR). RESULTS: ΔΔCT analysis with qRT-PCR revealed no significant change in gene expression of Bax, Bcl-2 or Fas within the ulcer, normal tissue and gastric cancer. No significant change was determined between Bax and Bcl-2 gene expression levels and applied EGF doses when groups were compared for each EGF dose. On the other hand, when 50 ng/µl of EGF was administered, Fas mRNA expression level was significantly lower in the gastric cancer cell line compared to patients with ulcer and normal gastroduodenal tissue (p<0.05). CONCLUSION: In this study which was done with a restricted patient group, our results revealed that apoptosis induced by Fas expression in gastroduodenal suppressing carcinogenesis process plays an active role in gaining anti-apoptotic properties of cells (Tab. 4, Fig. 2, Ref. 27).