BACKGROUND A major step during the evolution of tetrapods was their transition from water to land. This process involved the reduction or complete loss of the dermal bones that made up connections to the skull and a concomitant enlargement of the endochondral shoulder girdle. In the mouse the latter is derived from three separate embryonic sources: lateral plate mesoderm, somites, and neural cr...

In contrast to the classical assumption that neural crest cells are induced in chick as the neural folds elevate, recent data suggest that they are already specified during gastrulation. This prompted us to map the origin of the neural crest and dorsal neural tube in the early avian embryo. Using a combination of focal dye injections and time-lapse imaging, we find that neural crest and dorsal ...

The objective of this study on surgically assisted rapid maxillary expansion (RME) was to examine the extent of stress reduction in the midface and the cranial base with various surgical procedures. Four finite element models of the skull were generated (one without and three with different surgical incisions), in which a virtual RME (5 mm gap width) was simulated. In all four simulations, von-...

A sub-population of the neural crest is known to play a crucial role in development of the cardiac outflow tract. Studies in avians have mapped the complete migratory pathways taken by 'cardiac' neural crest cells en route from the neural tube to the developing heart. A cardiac neural crest lineage is also known to exist in mammals, although detailed information on its axial level of origin and...

A new monoclonal antibody, MEBL-1, which specifically recognizes melanocytes and their precursors, was used to examine the differentiation of neural crest cells into melanocytes in situ. MEBL-1-positive precursors of melanocytes in the trunk were first detected in mesenchyme located above the neural tube at the level of a wing bud at stage 19, when active migration of neural crest cells along t...

The possible role of a 140-kD cell surface complex in neural crest adhesion and migration was examined using a monoclonal antibody JG22, first described by Greve and Gottlieb (1982, J. Cell. Biochem. 18:221-229). The addition of JG22 to neural crest cells in vitro caused a rapid change in morphology of cells plated on either fibronectin or laminin substrates. The cells became round and phase br...

Neural crest cells originating in the occipital region of the avian embryo are known to play a vital role in formation of the septum of the cardiac outflow tract and to contribute cells to the aortic arches, thymus, thyroid and parathyroids. This 'cardiac' neural crest sub-population is assumed to exist in mammals, but without direct evidence. In this paper we demonstrate, using RT-PCR and in s...

BACKGROUND In view of the importance of neutral zone in complete denture construction, it was thought feasible to determine the relation between the centre of the alveolar ridge crest in relation to the neutral zone in a buccolingual direction which will help in positioning of the teeth in a region of minimum conflict so that the stability of the denture is enhanced. MATERIALS & METHODS The p...