Hydrogen and methane gases are frequently detected in the stomach

AIM： To investigate the incidence of bacterial overgrowth in the stomach by using a new endoscopic method in which intragastric hydrogen and methane gases are collected and analyzed. METHODS： Studies were performed in 490 consecutive patients undergoing esophagogastroscopy, At endoscopy, we intubated the stomach without inflation by air, and 20 mL of intragastric gas was collected through the biopsy channel using a 30 mL syringe, Intragastric hydrogen and methane concentrations were immediately measured by gaschromatography, H pylori infection was also determined by serology. RESULTS： Most of intragastric hydrogen and methane levels were less than 15 ppm （parts per million）. The median hydrogen and methane values （interquartile range） were 3 （1-8） ppm and 2 （1-5） ppm, respectively. The high hydrogen and methane levels for indication of fermentation were decided if the patient had the values more than 90 percentile range in each sample. When a patient had a high level of hydrogen or methane in one or more samples, the patient was considered to have fermentation. The overall incidence of intragastric fermentation was 15.4% （73/473）, Intragastric methane levels were higher in the postoperative group than in other groups. None of the mean hydrogen or methane values was related to Hpylori infection. CONCLUSION： Hydrogen and methane gases are more frequently detected in the stomach than expected, regardless of the presence of abdominal symptoms. Previous gastric surgery influences on the growth of methaneproducing bacteria in the fasting stomach.

Seventy-five gram glucose tolerance test to assess carbohydrate malabsorption and small bowel bacterial overgrowth

AIM： To investigate non-invasively the incidence of absorption of carbohydrates in diabetic patients during an oral glucose tolerance test （OGTT） and to determine whether malabsorption may be associated with insulin secretion and insulin resistance. METHODS： A standard 75-g OGTT was performed in 82 diabetic patients. The patients received 75 g of anhydrous glucose in 225 mL of water after an overnight fasting and breath samples were collected at baseline and up to 120 rain after ingestion. Breath hydrogen and methane concentrations were measured. Blood glucose and serum insulin concentrations were measured before ingestion and at 30, 60, 90, 120 rain post-ingestion. RESULTS： When carbohydrate malabsorption was defined as subjects with an increase of at least 10 ppm （parts per million） in hydrogen or methane excretion within a 2-h period, 28 （34%） had carbohydrate malabsorption. According to the result of increased breath test, 21 （75%） patients were classified as small bowel bacterial overgrowth and 7 （25%） as glucose malabsorption. Patients with carbohydrate malabsorption were older and had poor glycemic control as compared with those without carbohydrate malabsorption. The HOMA value, the sum of serum insulin during the test and the AinsulinlAglucose ratio were greater in patients with carbohydrate malabsorption. CONCLUSION： Insulin resistance may be overestimated by using these markers if the patient has carbohydrate malabsorption, or that carbohydrate malabsorption may be present prior to the development of insulin resistance. Hence carbohydrate malabsorption should be taken into account for estimating insulin resistance and β-cell function.