Patterns of senescence and apoptosis during development of branchial arches, epibranchial placodes, and pharyngeal pouches.

Background: Many developmental processes are coregulated by apoptosis and senescence. However, there is a lack of data on the development of branchial arches, epibranchial placodes, and pharyngeal pouches, which harbor epibranchial signaling centers.

Results: Using immunohistochemical, histochemical, and 3D reconstruction methods, we show that in mice, senescence and apoptosis together may contribute to the invagination of the branchial clefts and the deepening of the cervical sinus floor, in antagonism to the proliferation acting in the evaginating branchial arches.

Responses of Epibranchial Placodes to Disruptions of the FGF and BMP Signaling Pathways in Embryonic Mice.

Placodes are ectodermal thickenings of the embryonic vertebrate head. Their descendants contribute to sensory organ development, but also give rise to sensory neurons of the cranial nerves. In mammals, the signaling pathways which regulate the morphogenesis and neurogenesis of epibranchial placodes, localized dorsocaudally to the pharyngeal clefts, are poorly understood.

Holding donated human bodies in conservation: A novel interactive safe-keeping system meeting high ethical and safety standards.

"Mortui vivos docent". Learning from donated bodies is widely considered a corner stone in pre-clinical education, advanced clinical training, and scientific progress in medicine. Making such use of dead human bodies must, of course, accord with high ethical standards and legal constraints.

Chicken embryos share mammalian patterns of apoptosis in the posterior placodal area.

In the posterior placodal area (PPA) of C57BL/6N mice and primate-related Tupaia belangeri (Scandentia), apoptosis helps to establish morphologically separated otic and epibranchial placodes. Here, we demonstrate that basically identical patterns of apoptosis pass rostrocaudally through the Pax2 PPA of chicken embryos. Interplacodal apoptosis eliminates unneeded cells either between the otic anlage and the epibranchial placodes 1, 2 and/or 3, respectively (type A), or between neighbouring epibranchial placodes (type B).