The investigators will study 100 adult subjects over the age of 18 from the esophageal motility lab who are undergoing clinically indicated 24 hour acidity or basicity (pH) impedance and/or pH studies off acid suppressing medication.. These subjects will not have a prior history of esophageal surgery, or diagnosis of BE. The investigators will obtain consent for taking anthropometric measurements (Waist and hip circumference), and the results of their study. Only those subjects that successfully complete the 24 hour pH impedance studies will be included. Subjects will also undergo clinically indicated endoscopy. The investigators will consent these subjects to obtain 4 biopsies (bx) from the gastroesophageal (GE) junction and 4 bx from 5 cm above the GE junction. These bio-specimens will be stored for assessment of tissue injury (PGE2) and tissue immune-histochemistry of BE precursors (CDX1 and CDX2) at a later date.