Increased breath nitrous oxide after ingesting nitrate in patients with atrophic gastritis and partial gastrectomy

Creating a Framework for Treating Autoimmune Gastritis-The Case for Replacing Lost Acid

Autoimmune gastritis (AIG) is characterized by the destruction of gastric parietal cells, resulting in hypochlorhydria and eventual achlorhydria, as oxyntic glands in the corpus are destroyed and become atrophic. The permanent loss of gastric acid has many impacts-both theoretical and documented. The most concerning of these are hypergastrinemia and increased N-nitroso compounds, both of which increase the risk of gastric cancers. While known deficiencies of B12 and iron are often replaced in AIG, acid is not. Moreover, patients with AIG are often prescribed acid suppression for a stomach that is decidedly no longer acidic, worsening the sequelae of gastric atrophy. Betaine hydrochloride (BHCL) is a short-acting acidifying agent, available over the counter in capsule form. Mealtime acid supplementation has an historic basis and could ameliorate many AIG-related gastrointestinal symptoms. Theoretically, acidification could also reduce the potential for hypergastrinemia and the production of N-nitroso compounds, consequently reducing the risk of gastric cancers. Supplemental vitamin C may also help in preventing gastric N-nitroso formation, regardless of the gastric pH. This narrative review describes the functions of gastric acid in gastrointestinal and immune health, documents the effects of hypochlorhydria in AIG, and proposes potential options for safely re-establishing the acid milieu of the stomach for patients with AIG.

Sensor using a photo-acoustic absorption cell with two perpendicular acoustic resonators to analyze multiple molecules

An ultra-high sensitivity multi-molecule sensor based on a photo-acoustic cell with two perpendicular acoustic resonators and a common microphone has been reported. In this work, a 4.5 µm distributed-feedback quantum cascade laser and a 1.5 µm external cavity diode laser (EC-DL) were used as optical excitation sources. Considering the spectral ranges of the lasers used, it is possible to analyze eight molecules (Q C L:N 2 O and C O 2, EC-DL: H 2 O, H 2 S, N H 3, CO, C H 4, and C 2 H 2). The N 2 O molecule was used to evaluate the performance of the photo-acoustic spectroscopy (PAS)-based sensor. A sensitivity of 0.073 V/ppm and a linearity of 0.99 were found by analyzing the PAS signal as a function of N 2 O concentration at 2237.656c m -1. The long-term performance of the sensor was determined by performing an Allan deviation analysis. A minimum detection limit of 9.8 ppb for 90 s integration time was achieved. The simultaneous multi-trace gas detection capability was verified by measurement of N 2 O, C O 2, and H 2 O. Depending on the coarse/fine-tuning ranges of the lasers used, the number of molecules analyzed can be further increased. Such a sensor could provide simultaneous diagnosis of many diseases through an analysis of breath air and simultaneous monitoring of the most important greenhouse gases.

Gastric microbiota and predicted gene functions are altered after subtotal gastrectomy in patients with gastric cancer

Subtotal gastrectomy (i.e., partial removal of the stomach), a surgical treatment for early-stage distal gastric cancer, is usually accompanied by highly selective vagotomy and Billroth II reconstruction, leading to dramatic changes in the gastric environment. Based on accumulating evidence of a strong link between human gut microbiota and host health, a 2-year follow-up study was conducted to characterize the effects of subtotal gastrectomy. Gastric microbiota and predicted gene functions inferred from 16S rRNA gene sequencing were analyzed before and after surgery. The results demonstrated that gastric microbiota is significantly more diverse after surgery. Ralstonia and Helicobacter were the top two genera of discriminant abundance in the cancerous stomach before surgery, while Streptococcus and Prevotella were the two most abundant genera after tumor excision. Furthermore, N-nitrosation genes were prevalent before surgery, whereas bile salt hydrolase, NO and N2O reductase were prevalent afterward. To our knowledge, this is the first report to document changes in gastric microbiota before and after surgical treatment of stomach cancer.

Nitrous oxide production in sputum from cystic fibrosis patients with chronic Pseudomonas aeruginosa lung infection

Chronic lung infection by Pseudomonas aeruginosa is the major severe complication in cystic fibrosis (CF) patients, where P. aeruginosa persists and grows in biofilms in the endobronchial mucus under hypoxic conditions. Numerous polymorphonuclear leukocytes (PMNs) surround the biofilms and create local anoxia by consuming the majority of O₂ for production of reactive oxygen species (ROS). We hypothesized that P. aeruginosa acquires energy for growth in anaerobic endobronchial mucus by denitrification, which can be demonstrated by production of nitrous oxide (N₂O), an intermediate in the denitrification pathway. We measured N₂O and O₂ with electrochemical microsensors in 8 freshly expectorated sputum samples from 7 CF patients with chronic P. aeruginosa infection. The concentrations of NO₃⁻ and NO₂⁻ in sputum were estimated by the Griess reagent. We found a maximum median concentration of 41.8 µM N₂O (range 1.4–157.9 µM N₂O). The concentration of N₂O in the sputum was higher below the oxygenated layers. In 4 samples the N₂O concentration increased during the initial 6 h of measurements before decreasing for approximately 6 h. Concomitantly, the concentration of NO₃⁻ decreased in sputum during 24 hours of incubation. We demonstrate for the first time production of N₂O in clinical material from infected human airways indicating pathogenic metabolism based on denitrification. Therefore, P. aeruginosa may acquire energy for growth by denitrification in anoxic endobronchial mucus in CF patients. Such ability for anaerobic growth may be a hitherto ignored key aspect of chronic P. aeruginosa infections that can inform new strategies for treatment and prevention.

Gastric stump lymphoma after distal gastrectomy for benign peptic ulcer: Report of a case

We report a case of primary non-Hodgkin gastric stump lymphoma, found in a 78-year-old man 30 years after a distal gastrectomy for a benign peptic ulcer. The development of lymphoma in the gastric stump is rare. In fact, to our knowledge only 37 cases, including this one, have been documented. Although Helicobacter pylori is thought to be a predisposing factor, we found no histological evidence of this infection in our patient. Conversely, bile reflux and nitrite and N-nitrous compounds caused by abnormal bacterial growth in the gastric stump may play a role in inducing mucosa-associated lymphoid tissue lymphoma. The patient was treated by chemotherapy only, without surgery, which seems to be most appropriate for the early stages of this disease.