Koichi Nakakuki

The Novel Gene Encoding a Putative Transmembrane Protein Is Mutated in Gnathodiaphyseal Dysplasia (GDD)

Gnathodiaphyseal dysplasia (GDD) is a rare skeletal syndrome characterized by bone fragility, sclerosis of tubular bones, and cemento-osseous lesions of the jawbone. By linkage analysis of a large Japanese family with GDD, we previously mapped the GDD locus to chromosome 11p14.3-15.1. In the critical region determined by recombination mapping, we identified a novel gene (GDD1) that encodes a 913-amino-acid protein containing eight putative transmembrane-spanning domains. Two missense mutations (C356R and C356G) of GDD1 were identified in the two families with GDD (the original Japanese family and a new African American family), and both missense mutations occur at the cysteine residue at amino acid 356, which is evolutionarily conserved among human, mouse, zebrafish, fruit fly, and mosquito. Cellular localization to the endoplasmic reticulum suggests a role for GDD1 in the regulation of intracellular calcium homeostasis.

Potential marker of oral squamous cell carcinoma aggressiveness detected by fluorescence in situ hybridization in fine‐needle aspiration biopsies

Amplification of chromosome 11q13 is a frequent event in carcinogenesis of the head and neck squamous cell carcinomas including oral carcinoma.

Amphiregulin Induces Proliferative Activities in Osseous Dysplasia

Human osseous dysplasia (OD) is a benign fibro-osseous neoplasm of periodontal ligament origin in which normal bone is replaced with fibrous connective tissue containing abnormal bone or cementum. However, cellular differentiation and proliferation in OD have not been fully elucidated. In vitro culture systems have distinct advantages for analytical studies. Therefore, we established immortalized cell lines (OD-1) from OD lesions of the jaw from an individual with gnathodiaphyseal dysplasia (GDD). We hypothesized that OD-1 had a characteristic growth mechanism different from that of mineralized-associated cells such as osteoblasts. To clarify the difference of gene expression patterns between OD-1 and osteoblasts, we compared the profiles of genes expressed in the 2 cell types by microarray analysis. We identified amphiregulin to be highly expressed in OD-1 compared with osteoblasts and gingival fibroblasts. OD-1 showed proliferative activities regulated in an autocrine manner by amphiregulin, and amphiregulin may play a significant role in the proliferation of OD.

Collaborative treatment for a case of condylar hyperplastic facial asymmetry

Facial asymmetry can be caused by unilateral condylar hyperplasia. In such cases, it may be difficult to achieve symmetry since there is dentoalveolar compensation on the affected side, and the occlusal cant does not correspond to the frontal mandibular deviation. In the case presented, surgical orthodontic treatment and orthognathic surgery planning was accomplished for a patient with facial asymmetry due to condylar hyperplasia. The surgical plan was devised with particular attention to the severe dentoalveolar compensation. In this case, prior to the two-jaw surgery, the occlusal cant and frontal mandibular plane inclination was corrected through impaction of the left molar region by segmental osteotomy. Facial asymmetry and severe dentoalveolar compensation were successfully corrected after a unilateral segmental osteotomy and two-jaw surgery, resulting in a stable occlusal relationship and facial symmetry as well as good jaw function. Collaboration between the orthodontists and maxillofacial surgeons was essential for the successful treatment of the patient.

Occlusal Force and Nutritional Aspects after Postoperative Intermaxillary Fixation for Jaw Deformities

Objectives : Intermaxillary fixation (IMF) is used to rest the jaws of patients who have undergone orthognathic surgeries for jaw deformities, until the position of the jaws is stabilized. For the duration of the IMF, the patients are unable to consume solid food. Upon the release of the IMF, recovery until ingestion of solid food as a normal diet is gradual in accordance with the ability of mastication. The objective of the present study was to identify the nutritional issues associated with IMF and their influence on the occlusal force after the release of the IMF. Methods : Fifteen patients who underwent orthognathic surgery (sagittal split ramus osteotomy [SSRO] or SSRO combined with Le Fort I osteotomy) and postoperative IMF were measured for the occlusal force and body weight prior to orthognathic surgery, after the release of the IMF, and during their outpatient visits for up to 6 months after discharge. In addition, the date when the participants ate each of the listed food items for the first time after the release of the IMF was gathered from the patient reports during the 6-month post-orthognathic surgery follow-up. The nutrient intake over a month pre-admission and during the postdischarge period was also investigated by the food frequency method. Results : The occlusal force and body weight of the patients were reduced after orthognathic surgery and IMF, which required approximately 3 and 6 months for recovery, respectively. Similarly, the restoration to the regular diet required 3 months. Due to the decrease in the overall quantity of food consumption, the patients’ diet after discharge contained less energy than that during the pre-admission period. Furthermore, their intake of the nutrients related to wound healing was less than the estimated nutritional requirement of a physically unimpaired person. Conclusions : The patients’ food intake was reduced after orthognathic surgery and IMF, and it was associated with the reduction of occlusal force. Therefore, nutritional support, including advice on food choices and cooking methods, for approximately 3 months until the recovery of occlusal force, might be effective in improving the nutritional conditions and promoting wound healing in patients after orthognathic surgery and IMF.