Gastrointestinal contaminant (IMAGE) Xia & He Publishing Inc. Caption (a) Duodenal epithelium with goblet cells, PAP stain, 200×. (b) Gastric epithelium, Diff-Quik, 200×. PAP, Papanicolaou. Credit Minhua Wang, Guoping Ca Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. License CC BY-NC Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.