Subjects with Type 2 Diabetes undergoing a Roux-en-Y Gastric Bypass with a diagnosis of gastritis, esophagitis, ulcer, or other mucosal abnormality discovered at routine preoperative upper endoscopy, requiring follow-up endoscopy in the post-operative period.

Before Surgery: Subjects will have a visit where they will have a mixed nutrient stimulation test. They will be asked to fast for 12 hours prior to this visit (except water). During the visit they will drink an 8 ounce mixed nutrient liquid meal in 5 minute intervals over 20 minutes. During this visit a catheter will be placed in a vein in their arm for blood sample collections. A total of 50 ml of blood will be collected, (10 ml before drinking the mixed nutrient drink, at 30 minutes, at 60 minutes, at 90 minutes and 120 minutes after the mixed nutrient drink).

Gene and protein expression levels of GLUT-1 will be analyzed from the specimens obtained intra-operatively (baseline) and at 2 months post-operatively to determine if levels are significantly elevated above baseline. Quantitative real-time PCR and Western blot techniques will be utilized as described in C below.

Change in GLUT-1 levels will be correlated with changes in fasting glucose, mixed meal stimulation test, and homeostasis model assessment (HOMA). Secondly, at 2 months post-operatively, whole-body positron emission tomography/computed tomography (PET/CT) scanning with Fluorodeoxyglucose (FDG) will be performed to evaluate glucose uptake and utilization in the Roux limb.