Mesh : Bile Acids and Salts / analysis Bile Pigments / analysis Duodenal Ulcer / complications surgery Duodenogastric Reflux / diagnosis etiology therapy Electrodiagnosis / methods Gastrectomy / methods Gastric Emptying Gastritis / diagnosis etiology therapy Gastroesophageal Reflux / diagnosis etiology therapy Gastrointestinal Contents / analysis Humans Methods Postoperative Complications / therapy Stomach Ulcer / complications surgery Vagotomy / methods