Hox-A2 protein expression in avian jaws cartilages and muscle primordia development.

Objective: To elucidate the branchial origin of the articular and the square (homology of the malleus and the incus of mammals), we used immunohistochemistry to analyse the expression of the Hox-A2 protein during cephalogenesis in chickens.

Materials And Methods: Immunohistochemistry on paraffin sections of embryos from stage HH16 to HH40.

Results: In addition to the columella (equivalent to the mammalian stapes), the joint between the articular and the quadrate bones, and the retro-articular process of the articular (homologous to the short process of the malleus) express Hox-A2, suggesting an intervention of the 2nd arch in their formation.

Evolution and development of parrot pseudoteeth.

Parrot embryos carry peculiar appendages at their developing beak that have been described as pseudoteeth. To better characterize the pattern of development responsible for the emergence of these dental appendages, we examined parrot embryos combining conventional histology and microtomography approaches. Using immunohistochemistry, we observed the epithelial and mesenchymal expression of several proteins involved in tooth development in mammals.

Hox-A2 protein expression in mouse embryo middle ear ossicles.

The origin of the mammalian middle ear ossicles from mandibular and hyoid pharyngeal arches remains controversial and discussed. Two adverse theories are proposed. The first claims that malleus and incus derive from the Meckel's cartilage of the mandibular arch, and stapes from Reichert's cartilage of the hyoid arch.

Expression of Msx1 and Dlx1 during Dumbo rat head development: Correlation with morphological features.

The Dumbo rat possesses some characteristics that evoke several human syndromes, such as Treacher-Collins: shortness of the maxillary, zygomatic and mandibular bones, and low position of the ears. Knowing that many homeobox genes are candidates in craniofacial development, we investigated the involvement of the Msx1 and Dlx1 genes in the Dumbo phenotype with the aim of understanding their possible role in abnormal craniofacial morphogenesis and examining the possibility of using Dumbo rat as an experimental model for understanding abnormal craniofacial development. We studied the expression of these genes during craniofacial morphogenesis by RT-PCR method.

[Early treatment with rapid palatal expander and 3D Quad Action mandibular appliance: evaluation of a comprehensive approach in 22 patients].

Unlabelled: The aim of this retrospective study in mixed dentition was to quantify dental arches and radiographic changes with a rapid maxillary expander followed by a transpalatal bar with arms and a 3D Quad action mandibular appliance, at the end of the treatment (T1) and six months afterwards (T2).

Material And Methods: Thirty Class II patients in mixed dentition with tooth size-arch length discrepancies were studied (22 treated). We obtained measurements from dental casts before treatment, at T1 and T2 and radiographic changes at T1.

HSP110, caspase-3 and -9 expression in physiological apoptosis and apoptosis induced by in vivo embryonic exposition to all-trans retinoic acid or irradiation during early mouse eye development.

Apoptosis is an essential physiological process in embryonic development. In the developing eye of vertebrates, three periods of developmental apoptosis can be distinguished: early, intermediate and later. Within the apoptosis pathway, caspases play a crucial role.

Heat shock protein HSP86 expression during mouse embryo development, especially in the germ-line.

In addition to appearing in response to biological stresses, heat shock proteins are expressed as 'chaperones' by some cells living in physiological conditions. Among these proteins, the HSP90 family seems to function under normal growth conditions in the pathways of numerous signal transducers, cell-cycle and developmental regulators. The aim of this study was to investigate the immunohistochemical expression and the distribution of the two mammalian cytosolic isoforms of HSP90 (HSP84 and HSP86) during mouse development between E6 and E16.