A patient with a history of gastroesophageal reflux disease has been treated continuously with a proton pump inhibitor that substantially reduces gastric acid secretion.In comparison with a normal individual,the patient is at increased risk for which of the following?

A 30-year-old man is referred to a gastroenterologist for evaluation of persistent dyspepsia (indigestion).He is noted to have other symptoms,including flushing and hypotension,and after a bone marrow biopsy,systemic mastocytosis (an excessive proliferation of histamine-containing mast cells)is diagnosed.An increased propensity for gastric and duodenal ulcers in this patient is probably ascribable to overproduction of which of the following second messengers in gastric parietal cells?

A 60-year-old woman who is hospitalized during recovery from a hysterectomy does not have a bowel movement for several days,although she is eating solid foods.Because intestinal obstruction is suspected,she is returned to the operating room for an exploratory laparotomy.The pattern of motility most likely to be observed in her gastrointestinal tract during the surgery can best be described as: