During the embryonic development of vertebral cartilages, cells from the somite mesoderm differentiate into chondrocytes around the spinal cord and notochord. Grafting experiments in amphibian and chick embryos have indicated that the spinal cord and notochord have some influence on this differentiation of somite cells to cartilage (Holtzer & Detwiler, 1953; Watterson, Fowler & Fowler, 1954). F...

Background and Purpose. Tornwaldt's cysts are rare nasopharyngeal lesions that develop from remnants of the embryonic notochord. Summary of Case. We reported a twelve-year-old female stroke patient with Tornwaldt's cysts, whose father also suffered a stroke at age fifty two with the presence of an abdominal aortic aneurysm, suggesting a genetic influence in this case. Conclusions. This paper su...

The phylum Chordata is a large and diversified group containing more than 35,000 species, ranging from small wormlike forms to man. All chordates have three characteristics in common at some stage of their life cycle; a human embryo has the same notochord, a single, dorsal, tubular nerve cord, and pharyngeal gill slits as the lowest ancestral chordates. The primitive notochord, the predecessor ...

We have previously shown that the early Xenopus organiser contains cells equally potent to give rise to notochord or floor plate, and that Notch signalling triggers a binary decision, favouring the floor plate fate at the expense of the notochord. Now, we present evidence that Delta1 is the ligand that triggers the binary switch, which is executed through the Notch-mediated activation of hairy2...