Intragastric volatile N-nitrosamines, nitrite, pH, and Helicobacter pylori during long-term treatment with omeprazole

Gastric cancer in patients with Helicobacter pylori-negative autoimmune gastritis

Although Helicobacter pylori (H. pylori) is implicated in the development of most cases of gastric cancer with autoimmune gastritis, cases of gastric cancer have been reported in patients testing negative for H. pylori. Here, we aimed to outline the current research status of the factors involved in the development of gastric cancer in H. pylori-negative autoimmune gastritis. Predictive pathological conditions for the development of gastric cancer in H. pylori-negative autoimmune gastritis are postulated to be: (1) Severe atrophy; (2) Hypergastrinemia; (3) Bile reflux; and (4) Low acidity, which are directly related to the pathophysiology of autoimmune gastritis, as well as smoking and family history, which are not related to autoimmune gastritis. In autoimmune gastritis, where there is a possibility of spontaneous disappearance of H. pylori in advanced atrophy, it is difficult to assess H. pylori. Since H. pylori infection begins in the antrum and subsequently progresses to the proximal stomach, it is interpreted as H. pylori-negative autoimmune gastritis if histologically consistent with autoimmune gastritis in the body with spared antrum, and negative for other H. pylori tests. However, it is essential to examine whether the currently prevailing histological interpretation used to evaluate H. pylori infection status is appropriate.

The effect of phytochemicals in N-methyl-N-nitro-N-nitroguanidine promoting the occurrence and development of gastric cancer

Gastric cancer is a common malignant tumor of the digestive tract, with a low early diagnosis rate. N-methyl-N-nitro-N-nitroguanidine (MNNG) is one of the main risk factors for gastric cancer. Phytochemicals are healthy active substances derived from vegetables, fruits, nuts, tea, herbal medicines and other plants. Taking phytochemicals is a very promising strategy for the prevention and treatment of gastric cancer. Many studies have proved that phytochemicals have protective effects on MNNG induced gastric cancer via inhibiting cell proliferation, enhancing immunity, suppressing cell invasion and migration, inducing apoptosis and autophagy, blocking angiogenesis, inhibiting Helicobacter pylori infection as well as regulating metabolism and microbiota. The intervention and therapeutic effects of phytochemicals in MNNG induced gastric cancer have attracted more and more attention. In order to better study and explore the role, advantages and challenges of phytochemicals in MNNG induced gastric cancer, we summarized the intervention and therapeutic effects of phytochemicals in MNNG induced gastric cancer. This review may help to further promote the research and clinical application of phytochemicals in MNNG induced gastric cancer, and provide some new insights.

Helicobacter pylori and gastric microbiota homeostasis: progress and prospects

Helicobacter pylori, a Gram-negative microaerobic bacteria belonging to the phylum Proteobacteria, can colonize in the stomach and duodenum, and cause a series of gastrointestinal diseases such as gastritis, gastric ulcer and even gastric cancer. At present, the high diversity of the microorganisms in the stomach has been confirmed with culture-independent methods; some researchers have also studied the stomach microbiota composition at different stages of H. pylori carcinogenesis. Here, we mainly review the possible role of H. pylori-mediated microbiota changes in the occurrence and development of gastric cancer to provide new ideas for preventing H. pylori infection and regulating microecological imbalance.

Research progress of N-nitrosamine detection methods: a review

N-Nitrosamines (nitrosamines) are attracting increased attention because of their high toxicity and wide distribution. They have been strictly restricted by regulations in many fields. Researchers around the world have conducted substantial work on nitrosamine detection. This paper reviews the progress of research on nitrosamine detection methods with emphasis on biological-matrix samples. After introducing the category, toxicity, regulatory limit and source of nitrosamines, the paper discusses the most commonly used sample-preparation techniques and instrumental-detection techniques for nitrosamine detection, including some typical application cases.

High level nitrosamines in rat faeces with colorectal cancer determined by a sensitive GC-MS method

N-nitrosamines (NAs) are common toxic substances that have a strong correlation with many human diseases, such as liver damage and cancer. However, there is a lack of studies on methods involving the detection of NAs in biological samples, possibly owing to the interference of complex biological matrices and the influence of endogenous NAs. In this work, solid-phase extraction with mixed solid phases and adsorption sedimentation were used to successfully establish a gas chromatography-mass spectrometry (GC-MS) method for detecting eight NAs in rat faeces. Chromatographic separation of analytes was performed with Agilent VF-WAXms (30 m × 0.25 mm, 0.25 µm) GC columns. The LLOQs of eight NAs were set to the concentration of 0.5 ng/g and the obtained standard curves were linear, and correlation coefficients (r) were ≥ 0.99 for samples with concentration ranges of 0.5-500 ng/g. The inter and intra-assay precisions were< 15% for all analytes in the quality control samples, and the accuracies ranged from 88.67% to 108.33%. The extraction recoveries were above 78.56% for seven NAs, and a significant matrix effect was not observed. The application of this method revealed that the levels of NAS in the faeces of rats with colorectal cancer were higher than those of normal rats. Additionally, the effect of a high nitrite diet on NAs in faeces was analysed; the results confirmed that a high nitrite diet might contribute to an abnormal increase in NAs. Our work provides an analytical method for further in vivo study of NAs. Furthermore, a pilot study on the relationship between NAs and colorectal cancer was completed.

One stomach, two subtypes of carcinoma-the differences between distal and proximal gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors of the digestive tract, posing a significant risk to human health. Over the past 10 years, the pathological characteristics and the prognosis of GC have been determined based on the locations of the tumors that were then classified into two types-proximal and distal GC. This review focuses on the differences in epidemiology, etiology, cell source, pathological characteristics, gene expression, molecular markers, manifestations, treatment, prognosis, and prevention between proximal and distal GC to provide guidance and a basis for clinical diagnosis and treatment.

Anxiolytic effects of essential oils may involve anti-oxidant regulation of the pro-oxidant effects of ascorbate in the brain

Essential oils (EOs) absorbed via inhalation are consistently reported to produce anxiolytic effects. The underlying neurochemical mechanisms, however, are not well understood. High concentrations of ascorbate in the human brain (~10 mM in neurons) implicates this compound as a key signaling molecule and regulator of oxidative stress. In this study, we demonstrate the significant in vitro capacity of ascorbate to produce H₂O₂ in the presence of oxygen at physiological pH values, peaking at ~400 μM for ascorbate levels of 1.0 mg/mL (5.6 mM). In comparison, individual EOs and selected neurotransmitters at similar concentrations produced <100 μM H₂O₂. Systematic studies with binary and ternary mixtures containing ascorbate indicated that EOs and neurotransmitters could variably enhance (pro-oxidant, POX) or suppress (anti-oxidant, AOX) the production of H₂O₂ versus the ascorbate control, depending on the concentration ratios of the components in the mixture. Moreover, the AOX/POX chemistry observed with binary mixtures did not necessarily predict effects with ternary mixtures, where the POX ascorbate chemistry tended to dominate. A model is proposed to account for the ability of compounds with electron-donating capacity to catalytically regenerate ascorbate from intermediate oxidized forms of ascorbate, thus driving H₂O₂ production and exerting a net POX effect; whilst compounds that irreversibly reacted with oxidized forms of ascorbate suppressed the production of H₂O₂ and produced an overall AOX effect. Since the anxiolytic effects of different EOs, including extracts of Lavendula angustifolia (lavender) and Salvia rosmarinus (rosemary), were associated with AOX regulation of H₂O₂ production by ascorbate, it can be concluded that these anxiolytic effects are potentially related to the AOX properties of EOs. In contrast, EOs driving POX effects (eg, Junipenus communis (Juniper) berry EO) are proposed to be more useful for their potential anti-microbial or cancer cytotoxic applications.

Caenorhabditis elegans to Model the Capacity of Ascorbic Acid to Reduce Acute Nitrite Toxicity under Different Feed Conditions: Multivariate Analytics on Behavioral Imaging

Nitrocompounds are present in the environment and human diet and form part of vegetables and processed meat products as additives. These compounds are related to negative impacts on human and animal health. The protective effect of ascorbic acid has been demonstrated by some biological systems as regards several nitrocompounds. This work focused on studying the possibility of modeling this effect on nitrite toxicity with the model Caenorhabditis elegans. The three factors studied in this work were ascorbic acid concentration, nitrite exposure concentration, and presence/absence of food. The protective effect was evaluated by scoring lethality and its impact on behavior by means of multivariate statistical methods and imaging analytics. The effects of nitrite and the influence of food availability were evidenced. Apart from increasing lethality, nitrite had disruption effects on movements. All the observed symptoms reduced when ascorbic acid was administered, and it diminished lethality in all cases. Ascorbic acid maintained nematodes' postural capacities. The results suggest that nitrites' nonspecific toxicity in C. elegans can be mitigated by ascorbic acid, as previously evidenced in other biological systems. Thus, our results reveal the ability of C. elegans to reproduce the known protective effect of ascorbic acid against nitrite.

Risk of Cancer Following the Use of N-Nitrosodimethylamine (NDMA) Contaminated Ranitidine Products: A Nationwide Cohort Study in South Korea

N-nitrosodimethylamine (NDMA), a known carcinogenic agent, was recently detected in some products of ranitidine. Several studies have investigated the detectability of NDMA, in drugs and their risks. However, only a few epidemiological studies have evaluated cancer risk from the use of such individual drugs. This study investigates the risk of cancer in ranitidine users. We conducted an observational population-based cohort study using the Health Insurance Review and Assessment databases, which contain information about the use of medicines in South Korea. The primary study cohort consisted of ranitidine users (n = 88,416). For controls, we enrolled users of famotidine, another H2-receptor antagonist in which no NDMA has been detected. A 4:1 matched cohort was constructed to compare cancer outcomes of the two groups. Our matched cohort comprised of 40,488 ranitidine users and 10,122 famotidine users. There was no statistical difference in the overall cancer risk between the ranitidine and famotidine groups (7.45% vs. 7.56%, HR 0.99, 95% CI 0.91-1.07, p = 0.716). Additionally, no significant differences were observed in the analysis of 11 single cancer outcomes. We found no evidence that exposure to NDMA through ranitidine increases the risk of cancer.

Urinary exposure of N-nitrosamines and associated risk of esophageal cancer in a high incidence area in China

Esophageal cancer (EC) is a deadly malignancy worldwide with a high incidence and exhibits unevenly geographic prevalence, which suggests that environmental factors are deeply involved in the development of EC. Although the carcinogenesis of nitrosamines in the esophagus has been identified by tremendous toxicological data, the role of nitrosamines in the genesis of human EC has so far proved inconclusive largely due to a lack of convincing evidences. In this study, urinary nitrosamines in population controls and cases with esophageal precancerous lesions, including reflux esophagitis (RE) accompanying with basal cell hyperplasia (BCH) and dysplasia (DYS), and esophageal squamous cell carcinoma (ESCC) were detected by a SPE-LC-MS/MS method and the associated risk was evaluated. Higher excretion concentrations of N-nitrosomethylethylamine (NMEA) in the RE/BCH patients, NMEA and N-nitrosodibutylamine (NDBA) in the DYS patients, and NMEA, NDBA, N-nitrosopyrrolidine (NPyr) and N-nitrosomorpholine (NMor) in the ESCC patients were observed compared with the controls (p < .05). And with the progression of esophageal lesion, the exposure complexity increased in terms of the categories of nitrosamines. Furthermore, the observed positive associations between the hazardous exposure of NMEA, NDBA and NPyr and the increased risk of ESCC, and between NMEA and NDBA and RE/BCH were established. These findings provided direct evidence to support the hypothesis that exposure to nitrosamines are involved in the carcinogenesis of esophageal epithelia in this high incidence area from the perspective of endogenous exposure assessment. However, discoveries in this study need to be confirmed by systematic researches in the future. And the dose-response relationships, the reference ranges or cutoff values to predict the risks of nitrosamines exposure also need to be defined.

Gastric and duodenal ulcers, periodontal disease, and risk of bladder cancer in the Health Professionals Follow-up Study

PURPOSE

Studies suggest that peptic ulcer and periodontal disease are positively associated with bladder cancer risk. These two factors are likely to share common biologic mechanisms such as inflammation and dysbiosis. We examined the joint association of peptic ulcer (gastric/duodenal) and periodontal disease on bladder cancer risk.

METHODS

We conducted a prospective analysis among 45,185 men (563 invasive bladder cancer cases) in the Health Professionals Follow-Up Study (follow-up 1986-2016). History of ulcer and periodontal disease was self-reported at baseline and updated during the follow-up. Cox proportional hazards models estimated hazard ratio (HR) and 95% confidence interval (CI) for the joint associations of ulcers (gastric, duodenal) and periodontal disease, adjusting for age and other potential confounders. We tested for interaction using the Wald test for product terms.

RESULTS

Compared with men having no history of ulcer and periodontal disease, men with a history of peptic ulcer only (HR 1.22, 95% CI 0.90-1.66) and men with a history of periodontal disease only (HR 1.19, 95% CI 0.98-1.46) were associated with higher risk of invasive bladder cancer. The highest bladder cancer risk was observed in men with a history of both peptic ulcer and periodontal disease (HR 1.52, 95% CI 1.05-2.20). Similar results were found when we stratified by ulcer types. The interactions between ulcer and periodontal disease were not statistically significant for all ulcer types (p-interaction ≥ 0.59).

CONCLUSION

We did not find sufficient evidence for interaction between gastric/duodenal ulcers and periodontal disease on bladder cancer risk.

Distribution of N-nitrosamines in drinking water and human urinary excretions in high incidence area of esophageal cancer in Huai'an, China

The Huai'an area in Jiangsu Province of East China is an endemic region of esophageal cancer (EC). The regional heterogeneity of EC suggests that the levels of potential carcinogens might vary throughout the environment. It has been suggested that the most likely carcinogens related to EC are a group known as the N-nitrosamines. In this study, we measured the concentrations of nine nitrosamines in drinking water and human urine in two areas in China, one with a high incidence of EC (Huai'an) and one with a low incidence (Nanjing). Among the nine target analytes, N-nitrosodi-n-propylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopyrrolidine (NPyr), N-nitrosodiethylamine (NDEA) and N-nitrosomorpholine (NMor) occurred at higher concentrations in drinking water in the high incidence area. Inhabitants from the high incidence area also had urinary excretions with significantly higher concentrations of NDEA, NDBA, N-nitrosopiperidine (NPip) and N-nitrosodiphenylamine (NDPhA). These findings indicated that people in the high EC incidence area were exposed to higher levels of nitrosamines. However, the association between the incidence of EC and nitrosamines exposure will need to be evaluated in more detail.

The Signaling Pathways in Nitric Oxide Production by Neutrophils Exposed to N-nitrosodimethylamine

Background:

Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern.

Results:

In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils.

Conclusion:

This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.

Elevated urinary levels of carcinogenic N-nitrosamines in patients with urinary tract infections measured by isotope dilution online SPE LC-MS/MS

N-nitrosamines (NAms) are well-documented for their carcinogenic potential. Human exposure to NAms may arise from the daily environment and endogenous formation via the reaction of secondary amines with nitrites or from bacteria infection. We describe the use of isotope dilution online solid-phase extraction (SPE) LC-MS/MS to quantify nine NAms in human urine. This method was validated and further applied to healthy subjects and patients with urinary tract infection (UTI). N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR) and N-nitrosomorpholine (NMOR) were analyzed with an APCI source, while N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosodi-n-propylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA) were quantified with an ESI source, due to their effect on the sensitivity and chromatography. NDMA was the most abundant N-nitrosamine, while NDPhA was firstly identified in human. UTI patients had three to twelve-fold higher concentrations for NDMA, NPIP, NDEA, NMOR and NDBA in urine than healthy subjects, and the NAms were significantly decreased after antibiotics treatment. NDMA concentrations were also significantly correlated with the pH value, leukocyte esterase activity or nitrite in urines of UTI patients. Our findings by online SPE LC-MS/MS method evidenced that UTI patients experienced various NAms exposures, especially the potent carcinogen NDMA, which was likely induced by bacteria infection.

The stomach in health and disease

The stomach is traditionally regarded as a hollow muscular sac that initiates the second phase of digestion. Yet this simple view ignores the fact that it is the most sophisticated endocrine organ with unique physiology, biochemistry, immunology and microbiology. All ingested materials, including our nutrition, have to negotiate this organ first, and as such, the stomach is arguably the most important segment within the GI tract. The unique biological function of gastric acid secretion not only initiates the digestive process but also acts as a first line of defence against food-borne microbes. Normal gastric physiology and morphology may be disrupted by Helicobacter pylori infection, the most common chronic bacterial infection in the world and the aetiological agent for most peptic ulcers and gastric cancer. In this state-of-the-art review, the most relevant new aspects of the stomach in health and disease are addressed. Topics include gastric physiology and the role of gastric dysmotility in dyspepsia and gastroparesis; the stomach in appetite control and obesity; there is an update on the immunology of the stomach and the emerging field of the gastric microbiome. H. pylori-induced gastritis and its associated diseases including peptic ulcers and gastric cancer are addressed together with advances in diagnosis. The conclusions provide a future approach to gastric diseases underpinned by the concept that a healthy stomach is the gateway to a healthy and balanced host. This philosophy should reinforce any public health efforts designed to eradicate major gastric diseases, including stomach cancer.

Clinical utility of esomeprazole for treatment of gastroesophageal reflux disease in pediatric and adolescent patients

Gastroesophageal reflux is a common condition in the pediatric population, with an increasing incidence in the last few years. It can be defined as an effortless retrograde movement of gastric contents into the esophagus related to complex multifactorial pathogenesis, involving anatomical, hormonal, environmental, and genetic factors. In some cases, it may be associated with esophageal or extraesophageal symptoms (heartburn and regurgitation), and is defined as gastroesophageal reflux disease (GERD). The therapeutic approach to gastroesophageal reflux in infants and children is often conservative, including changes in lifestyle (eg, posture and thickening of meals). If these children remain symptomatic after lifestyle changes (nutrition, feeding, and positional modification), or present with clinical red flags (poor weight gain, recurrent respiratory symptoms, or hematemesis) and complications of GERD (esophagitis, bleeding, stricture, Barrett’s esophagus, or adenocarcinoma) it may be necessary to set up a proper diagnostic protocol. Proton pump inhibitors have been recommended as the most effective acid suppression therapy for adults and pediatric patients. Esomeprazole, the S-isomer of omeprazole, is the only single-isomer proton pump inhibitor available. The paper assesses the safety and tolerability of esomeprazole in pediatric and adolescent patients.

Proton pump inhibitors and histamine-2-receptor antagonists and pancreatic cancer risk: a nested case-control study

BACKGROUND

The relationship between use of proton pump inhibitors (PPIs) and histamine-2-receptor antagonists (H(2)RAs) and pancreatic cancer risk has yet to be examined. Data from a range of studies suggest biologically plausible mechanisms, whereby these drugs (or the conditions for which they are prescribed) may affect pancreatic cancer risk. The objective of this study was to investigate the relationship between use of PPIs/H(2)RAs and pancreatic cancer risk.

METHODS

A nested case-control study was conducted within the UK general practice research database (GPRD). Cases had a diagnosis of exocrine pancreatic cancer and controls were matched to cases on general practice site, sex and year of birth. Exposure to PPIs and to H(2)RAs since entry into GPRD until 2 years before the diagnosis date (corresponding date in controls) and in the 5 years before the diagnosis date were separately assessed. Conditional logistic regression analyses were used to generate odds ratios (ORs) and 95% confidence intervals (CIs) associated with PPI or H(2)RA use compared with nonuse.

RESULTS

Ever use of PPIs since entry into the GPRD (excluding the 2 years prior to diagnosis) was not associated with risk of pancreatic cancer; OR (95% CI) 1.02 (0.85-1.22). Neither the dose nor the duration of PPI or H(2)RA use was associated with pancreatic cancer risk. No consistent patterns of association were seen when cumulative exposure (dose and duration) to these drugs was examined separately or together.

CONCLUSION

PPI/H(2)RA use, in a UK population, was not associated with pancreatic cancer risk.

Which is the best choice for gastroesophageal disorders: Melatonin or proton pump inhibitors?

Melatonin is used in many countries to improve sleep disorders. Melatonin is a hormone produced by the pineal gland and enterochromaffin cells which control sleep and gastrointestinal motility. Low levels of melatonin lead to gastroesophageal reflux disease (GERD). Most of patients with GERD have a sleep disorder. So, low melatonin levels is the main cause of insomnia. Beyond this, it has an inhibitory action on gastric acid secretion and seems to control the lower esophageal sphincter. Proton pump inhibitors (PPIs) are a group of drugs whose main action is a pronounced and long-lasting reduction of gastric acid production. They are the most potent inhibitors of acid secretion available today. Omeprazole (one of the PPIs) and melatonin have similarities in their chemical structures. Therefore, we could consider omeprazole as a rough copy of melatonin. In this paper, we compare the advantages and disadvantages of the clinical use of melatonin and PPIs.

Which is the best choice for gastroesophageal disorders: Melatonin or proton pump inhibitors?

Melatonin is used in many countries to improve sleep disorders. Melatonin is a hormone produced by the pineal gland and enterochromaffin cells which control sleep and gastrointestinal motility. Low levels of melatonin lead to gastroesophageal reflux disease (GERD). Most of patients with GERD have a sleep disorder. So, low melatonin levels is the main cause of insomnia. Beyond this, it has an inhibitory action on gastric acid secretion and seems to control the lower esophageal sphincter. Proton pump inhibitors (PPIs) are a group of drugs whose main action is a pronounced and long-lasting reduction of gastric acid production. They are the most potent inhibitors of acid secretion available today. Omeprazole (one of the PPIs) and melatonin have similarities in their chemical structures. Therefore, we could consider omeprazole as a rough copy of melatonin. In this paper, we compare the advantages and disadvantages of the clinical use of melatonin and PPIs.

Larger amounts of nitrite and nitrate-reducing bacteria in megaesophagus of Chagas' disease than in controls

In the megaesophagus of Chagas' disease, chronic esophagitis is caused by stasis of swallowed food and saliva. In this environment, the overgrowth of aerobic and anaerobic bacteria, including nitrate-reducing bacteria, is observed. The reduction of nitrate into nitrite by the action of these bacteria has been associated with the formation of volatile nitrosamines in different situations of gastric bacterial overgrowth. We have hypothesized that this phenomenon could occur in the esophageal lumen of patients with megaesophagus. To evaluate the concentration of nitrite, the presence of volatile nitrosamines and the concentration of nitrate-reducing bacteria in the esophageal lumen of patients with non-advanced megaesophagus of Chagas' disease and in a group of patients without esophageal disease. Fifteen patients with non-advanced megaesophagus [megaesophagus group (MG)] and 15 patients without any esophageal disease [control group (CG)] were studied. Saliva samples were taken for nitrate and nitrite quantitative determination and esophageal stasis liquid samples were taken for nitrate and nitrite quantitative determination, volatile nitrosamines qualitative determination and reductive bacteria quantitative determination. MG and CG were equivalent in nitrate and nitrite saliva concentration and in nitrate esophageal concentration. Significant difference was found in nitrite (p = 0.003) and reductive bacteria concentration (p < 0.0001), both higher in MG. Volatile nitrosamines were identified in three MG patients and in none of the CG patients, but this was not significant (p = 0.113). There is a higher concentration of reductive bacteria in MG, responsible for the rise in nitrite concentration at the esophageal lumen and, eventually, for the formation of volatile nitrosamines.

Regression of gastroesophageal reflux disease symptoms using dietary supplementation with melatonin, vitamins and aminoacids: comparison with omeprazole

The prevalence of gastroesophageal reflux disease (GERD) is increasing. GERD is a chronic disease and its treatment is problematic. It may present with various symptoms including heartburn, regurgitation, dysphagia, coughing, hoarseness or chest pain. The aim of this study was to investigate if a dietary supplementation containing: melatonin, l-tryptophan, vitamin B6, folic acid, vitamin B12, methionine and betaine would help patients with GERD, and to compare the preparation with 20 mg omeprazole. Melatonin has known inhibitory activities on gastric acid secretion and nitric oxide biosynthesis. Nitric oxide has an important role in the transient lower esophageal sphincter relaxation (TLESR), which is a major mechanism of reflux in patients with GERD. Others biocompounds of the formula display anti-inflammatory and analgesic effects. A single blind randomized study was performed in which 176 patients underwent treatment using the supplement cited above (group A) and 175 received treatment of 20 mg omeprazole (group B). Symptoms were recorded in a diary and changes in severity of symptoms noted. All patients of the group A (100%) reported a complete regression of symptoms after 40 days of treatment. On the other hand, 115 subjects (65.7%) of the omeprazole reported regression of symptoms in the same period. There was statiscally significant difference between the groups (P < 0.05). This formulation promotes regression of GERD symptoms with no significant side effects.

Review article: proton pump inhibitors and bacterial overgrowth

Proton pump inhibitors are potent drugs producing profound suppression of gastric acid secretion. Consequently, they are highly effective at treating acid-related disorders. There have been concerns that the suppression of gastric acid will alter the bacterial flora of the upper gastrointestinal tract and lead to complications such as cancer, enteric or other infections and malabsorption. Studies have confirmed that proton pump inhibitors do alter the bacterial population but present evidence indicates that this only rarely leads to clinical disease. As with all drugs, proton pump inhibitors should only be used for disorders shown clearly to benefit from the therapy and where the benefits will outweigh the small risks associated with them. Further research to more fully quantify the risk associated with PPI therapy is required.

Neutrophil-mediated formation of carcinogenic N-nitroso compounds in an in vitro model for intestinal inflammation

In order to study neutrophil-mediated formation of carcinogenic N-nitroso compounds as a mechanism of inflammation-related colon carcinogenesis, we designed an in vitro model for intestinal inflammation, consisting of a coincubation system with human colon cells (Caco-2 cells) and activated human neutrophils (PMN), as important immunoreactive cells. We investigated whether nitrosamines and nitrosamides could be formed upon addition of dimethylamine, morpholine and methylurea to the coincubations as nitrosatable precursors, which are known to produce carcinogenic N-nitroso compounds. Incubations of pure nitric oxide with dimethylamine and morpholine showed that NO-mediated formation of nitrosodimethylamine and nitrosomorpholine is possible under the incubation conditions. During the coincubations of activated PMN and Caco-2 cells, 0.34 nmol nitrite/10(6) PMN was produced. Dose-dependent formation of NMOR was observed in this PMN/Caco-2 system; addition of 5mM morpholine resulted in a significantly increased NMOR formation of 4.2 nM. However, no detectable NDMA and methylnitrosourea were formed in this coincubation system. These results suggest that activated human neutrophils are able to synthesize carcinogenic N-nitrosamines, e.g. NMOR, which implies a risk of colon carcinogenesis during chronic inflammation. However, the observed relatively low level of nitrosation suggests that also other risk factors are contributing to the association between chronic inflammation and colon cancer risk.

Peptic ulcer disease and the risk of bladder cancer in a prospective study of male health professionals

Helicobacter pylori is a risk factor for gastric and duodenal ulcers, but gastric ulcers generally occur in individuals who have low acid production and diffuse gastritis, whereas duodenal ulcers are more likely to occur with high acid output and antrum-predominant gastritis. Low acid production, gastritis, and ulcer healing each contribute to poor antioxidant absorption, oxidative stress, and elevated nitrite levels in the stomach. N-Nitrosamines are known carcinogens, and nitrate ingestion has been related to bladder cancer risk. Consequently, we hypothesized that the gastric conditions associated with gastric ulcers may contribute to elevated bladder cancer risk. We thus examined the association between self-reported history of peptic ulcer disease and the risk of bladder cancer (414 cases) over 14 years of follow-up in the Health Professional Follow-Up Study. Cox proportional hazards models were performed to adjust for known risk factors of bladder cancer. Men who reported a gastric ulcer before 1986 had a significantly higher risk of bladder cancer compared with those with no history of gastric ulcer (relative risk = 1.55, 95% confidence interval = 1.03-2.33, controlling for smoking and other potential confounders). No association was observed for duodenal ulcers (multivariate relative risk = 0.97, 95% confidence interval = 0.68-1.38). The ulcers in this study were based solely on self-report and not medical records; consequently, misclassification of ulcers may have occurred. Although intriguing, these findings need to be replicated.

Helicobacter pylori infection and increased nitrite synthesis in the stomach. Inflammation and atrophy connections

BACKGROUND

We have previously shown that the nitrite content in the gastric juice of Helicobacter pylori-positive patients is significantly higher than that of H. pylori-negative patients and it decreases after eradication of H. pylori.

AIM

To examine the relationship between the nitric oxide synthesis in the gastric lumen and histological findings.

METHODS

Eighty-five middle aged Japanese patients were studied. Four specimens, each obtained from the greater and lesser curvature of antrum and gastric body were processed for the determination of histopathological scores using the updated Sydney System. Gastric juice was collected endoscopically to determine the concentration of nitrite using a modified Griess reaction.

RESULTS

There was a significant positive correlation between the nitrite and the pH levels (r = 0.81, P < 0.001) and between the pH levels and the histopathological scores in the corpus. The gastric juice pH and concentration of the nitrite increased in patients with histological diagnosis of normal, antral-predominant gastritis, pangastritis and corpus-predominant gastritis in due order.

CONCLUSIONS

H. pylori infection effects nitric oxide synthesis in the gastric lumen which is mainly connected with hypoacidity. The gastric juice pH is one of the useful markers for corpus dominant gastritis and probably for high-risk group of gastric cancer.

Microbiota do megaesôfago e carcinogênese

INTRODUÇÃO: O risco de desenvolvimento de carcinoma esofágico em portadores de megaesôfago é 33 vezes superior ao da população em geral. Possível explicação para este fenômeno poderia estar relacionada à produção de compostos N-nitrosos na luz do órgão, a partir da transformação de nitratos da dieta em nitritos, mediada por bactérias em suspensão no líquido de estase e com o contato crônico destes carcinógenos com a mucosa esofágica. OBJETIVO: Analisar a microbiota esofágica em pacientes portadores de megaesôfago de etiologia chagásica, com especial atenção para a presença de bactérias com capacidade de redução de nitratos. CASUÍSTICA: Foram estudados prospectivamente 15 pacientes portadores de megaesôfago chagásico com idades variando de 28 a 73 anos, sendo 9 do sexo feminino e 6 do sexo masculino, que foram divididos em 3 grupos iguais de 5, de acordo com o grau de dilatação do esôfago, segundo a classificação de Rezende et al. (Grau I, Grau II e Grau III). MÉTODO: A coleta do líquido de estase para estudo microbiológico era realizada através de sonda de Levine nº 14, que era passada pela boca, por dentro de uma cânula de intubação orotraqueal nº 7,5, mantendo-se sua extremidade escondida, a fim de evitar sua contaminação. RESULTADOS: Foram obtidas 93,3% de culturas positivas com grande variedade de microrganismos e predomínio de aeróbios Gram-positivos e anaeróbios. As concentrações de microrganismos foram tanto maiores, quanto maior o grau de dilatação do esôfago. Entre os microrganismos encontrados, o Staphylococcus sp, Corynebacterium sp, Peptostreptococcus sp e a Veillonella sp foram aqueles identificados como tendo a capacidade de redução de nitratos a nitritos. CONCLUSÃO: No megaesôfago chagásico há bactérias na luz do órgão com capacidade de redução de nitratos da dieta, passo importante na produção de compostos N-nitrosos.

Oesophageal disorders: future developments

Elicitation of the characteristic symptom patterns remains the primary approach to the diagnosis of gastro-oesophageal reflux disease, and this may be enhanced by developments in the use of high-resolution endoscopy and oesophageal biopsy. For future therapy, proton pump inhibitors and anti-reflux surgery may compete with reversible acid pump blockers, reflux inhibitor drugs and diverse luminally delivered physical anti-reflux therapies. Short-segment Barrett's oesophagus is known to be highly prevalent, but its impact on the risk of adenocarcinoma remains poorly defined. Biomarkers for Barrett's oesophagus have been proposed to aid in the stratification of cancer risk, and cytology may assume more importance in the future. Endoscopic surveillance for Barrett's oesophagus is widely practised, but more data are needed to demonstrate cost-effectiveness and a positive impact on mortality. Animal and limited human studies suggest that chemoprevention may become an important strategy in reducing the risk of adenocarcinoma. The ablation of Barrett's epithelium results in a reversal of Barrett's epithelium, albeit with an uncertain long-term outcome.