Meer-Fieggen, W. van der

crypt activity resection villu proliferative activity germfree animal number carboxyl esterase activity cell proliferation crypt cells time intervals proliferative esterase villus cells control proliferation result irradiation germfree rats interval intestine table carboxyl migration percentage compartment epithelium villi position germfree animals 48 hours effect value turnover time study duodenum regulation group differentiation 12 hours column proliferative cell compartment h-thymidine maturation chapter localization analyses radiation migration rate jejunum section intermitotic time non-irradiated esterase activity crypt cell compartment turnover cell compartment decrease chapter ii segment autoradiography cell maturation expansion increase dna synthesis radiation dose enzyme ileum recovery tissue process incorporation labelling 1969. cell position treitz repopulation intermitotic mechanism