“…According to their results [1,2], they may be undifferentiated epithelial crypt cells, although it has not been possible to induce their complete differentiation in vitro. Recently, Kedinger et al [3] succeeded in inducing their complete differentiation by sandwiching IEC-17 cells, which are similar to IEC-18 cells, between two homotopic fetal rat intestine mesenchymes, followed by grafting under the kidney capsule of an Correspondence address: T. Shintani. Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Kyoto 606, Japan adult rat.…”