Endothelin-1 regulates the dorsoventral branchial arch patterning in mice.

Endothelin-1 (ET-1), a 21-amino acid peptide secreted by the epithelium and core mesenchyme in the branchial arches as well as vascular endothelium, is involved in craniofacial and cardiovascular development through endothelin receptor type-A (EdnrA) expressed in the neural crest-derived ectomesenchyme. Here we show that ET-1(-/-) mutant mice exhibit a homeotic-like transformation of the lower jaw to an upper jaw. Most of the maxillary arch-derived components are duplicated and replaced mandibular arch-derived structures, resulting in a mirror image of the upper and lower jaws in the ET-1(-/-) mutant. As for hyoid arch-derivatives, the ventral structures are severely affected in comparison to the dorsal ones in the ET-1(-/-) mutant. Correspondingly, the expression of Dlx5 and Dlx6, Distalless-related homeobox genes determining the ventral identity of the anterior branchial arches, and of the mandibular marker gene Pitx1 is significantly downregulated in the ET-1(-/-) mutant, whereas the expression of Dlx2 and the maxillary marker gene Prx2 is unaffected or rather upregulated. These findings indicate that the ET-1/EdnrA signaling may contribute to the dorsoventral axis patterning of the branchial arch system as a mediator of the regional intercellular interactions.

Type I collagen regulated dentin matrix protein-1 (Dmp-1) and osteocalcin (OCN) gene expression of rat dental pulp cells.

In this study, we investigated the effect of type I collagen on dentin matrix protein-1 (Dmp-1) and osteocalcin (OCN) gene expression of dental pulp cells. The mRNA level of Dmp-1 gene was down-regulated; however, OCN gene expression was up-regulated by the culture of dental pulp cells with type I collagen. These findings imply that type I collagen regulates mRNA level of Dmp-1 and OCN gene that are predominantly expressed in active odontoblasts. The change of gene expression by type I collagen was suppressed by the blocking of collagen-integrin interaction. We could conclude that the effect of type I collagen was mediated via binding of collagen to integrin receptors.

Indications and procedures for segmental dentoalveolar osteotomy: a review of 13 patients.

The authors evaluated the surgical area, indications, and procedures for segmental dentoalveolar osteotomy carried out on 16 jaws in 13 patients treated at the Department of Oral and Maxillofacial Surgery, Kobe University Graduate School of Medicine, between 1990 and 2001. Osteotomy was indicated mainly in cases where tooth repositioning by orthodontic treatment was limited, where social conditions (e.g., age, time, finances) precluded orthodontic treatment, or where revision of orthodontic or surgical treatment was required. In cases of maxillary anterior segmental dentoalveolar osteotomy, the modified Wunderer method was used, where after an incision was made in the palatal mucosa, a mucoperiosteal flap was abraded as much as possible until the area of the osteotomy on the palatal side could be visualized. In maxillary posterior segmental dentoalveolar osteotomy, the operation was carried out in 2 stages because of the risk of necrosis of the bone fragments. In the first stage, an osteotomy was carried out on the vestibular side, since the vestibular gingival pedicle was intact. In the second stage, 3 weeks later, another osteotomy was performed after the palatal mucoperiosteal flap was abraded to visualize the area of the osteotomy as well as that of the maxillary anterior segmental dentoalveolar osteotomy.