A 45-year-old man complains of burning epi- gastric pain that wakes him up at night. The pain is relieved by eating or using over-the- counter antacids and H2 blockers. Diagnosis is best confirmed by which of the following? 

A 64-year-old woman with arthritis is a chronic NSAID user. She develops severe epigastric pain and undergoes an upper endoscopy. She is told that she has an ulcer adjacent to the pylorus. Which of the following is TRUE about the pylorus? 

A 30-year-old executive learns that he has a duo- denal ulcer. His gastroenterologist prescribes and outlines medical therapy. The patient worries that if medical therapy fails he may need surgery. Which of the following is the best indication for elective surgical therapy for duodenal ulcer disease? 

A 44-year-old dentist was admitted to the hos- pital with a 1-day history of hematemesis caused by a recurrent duodenal ulcer. He has shown considerable improvement following operative treatment by a truncal vagotomy and pyloroplasty, 10 years prior to this incident. Which is TRUE of truncal vagotomy? 

A 42-year-old executive has refractory chronic duodenal ulcer disease. His physican has sug- gested several surgical options. The patient has chosen a parietal (highly selective) vagotomy instead of a truncal vagotomy and antrectomy because?