Gastric Pathophysiology in Diabetes

Inclusion Criteria (diabetic group): * Diabetes mellitus type I or II, minimal duration of the disease 3 years, minimal duration of specific treatment (drugs, insulin) 2 years Exclusion Criteria (diabetic group): * Diabetes mellitus type II being treated with a diet only * Severe acute decompensation of diabetes (uncontrolled diabetes) necessitating hospitalization * Concomitant treatment with more than one prokinetic agent * Active treatment with opioids or a history of treatment with opioids within 12 months before enrolment * Previous esophageal or major gastric surgery (e.g. esophageal myotomy, esophagectomy, antireflux surgery, Billroth I or II gastric resection, gastric pull-through, pyloromyotomy, pyloroplasty, gastric electrical stimulation) * Organic pyloric (or intestinal) obstruction (fibrotic stricture, etc.) * Severe coagulopathy * Esophageal or gastric varices and /or portal gastropathy * Advanced liver cirrhosis * Pregnancy or puerperium * Malignant or pre-malignant gastric diseases (dysplasia, gastric cancer, GIST): patients with a history of such disease after its cure are eligible for enrolment * The presence of a rumination syndrome or eating disorders (anorexia nervosa, bulimia). In case of doubts, a psychiatric examination will be performed. * Systemic connective tissue disorder * Inability to obtain informed consent * Any other condition, which in the opinion of the investigator would interfere with study requirements