Toshio Sakaki

Correlation of E‐and P‐cadherin expression with differentiation grade and mode of invasion in gingival carcinoma

The expression pattern of two Ca2+‐dependent cell‐cell adhesion molecules, E‐and P‐cadherin (CD), in 25 primary gingival squamous cell carcinomas (SCC) was examined immunohistochemically. The occurrence of reduced‐type expression of both E‐and P‐CD increased significantly with the grade of carcinoma differentiation, culminating in a complete loss of P‐CD in poorly differentiated SCC. The occurrence of reduced‐type P‐CD expression also increased significantly with the mode of invasion, as was the case with E‐CD. Furthermore, no P‐CD molecules were detected in one of the six SCC having a diffuse, cord‐like invasion and in three of the six having a diffuse type of invasion. These findings suggest that the down‐regulation of these cell adhesion molecules closely correlates with the differentiation grade and mode of invasion of gingival SCC.

LOCALIZATION OF E-CADHERIN ADHESION MOLECULES IN HUMAN GINGIVA AND GINGIVAL CARCINOMA

Immunohistochemical investigations were carried out on the localization and expression of the Ca2+‐dependent intercellular adhesion molecule E‐cadherin in human gingiva and gingival carcinoma. Although E‐cadherin did not appear in the parakeratinized layer of either clinically healthy or inflamed gingiva, it did appear strongly in the prickle layer and somewhat more weakly in the basal layer. Immunogold particles reactive to anti‐E‐cadherin monoclonal antibody in the electron microscopic findings were localized only in the vicinity of the desmosomes of the prickle and basal layers.

Correlation of P-cadherin and β-catenin expression and phosphorylation with carcinogenesis in rat tongue cancer induced with 4-nitroquinoline 1-oxide

Using biochemical and immunohistochemical techniques, we have investigated P-cadherin, beta-catenin, c-src and c-met protein expression, and phosphorylation of beta-catenin in a rat model of tongue cancer induced with 4-nitroquinoline 1-oxide. Six-week-old male Sprague-Dawley rats were given either normal drinking water (controls) or 50 ppm 4NQO solution as drinking water for 16 and 20 weeks. This treatment produced dysplasia and well-differentiated squamous cell cancer in rat tongues after 16 and 20 weeks, respectively. In controls, P-cadherin and beta-catenin were expressed only in cell membranes of tongue suprabasal epithelial cells, whereas strong reaction to P-cadherin antibody was observed during carcinogenesis, especially in nests of cancer cells. However, dysplastic and cancer cells expressed beta-catenin not only in cell membranes but also in the nuclear and cytoplasmic compartments. During carcinogenesis, immunohistochemical reaction to phosphotyrosine increased gradually. Reaction to the c-src product was strongest at the dysplastic stage and, to the c-met product, at the cancer stage. In addition, western blotting analysis showed a marked increase in the expression of beta-catenin and phosphotyrosine in dysplastic and cancer cells compared with the controls. Using immunoprecipitation and western blotting techniques, we found that phosphorylated beta-catenin gradually increased during carcinogenesis. These experiments demonstrate that cell-cell adhesion in epithelial cells was reduced by phosphorylation of beta-catenin and that beta-catenin overexpression in nuclear and cytoplasmic compartments during carcinogenesis and the production of the c-met product that is associated with the phosphorylation of beta-catenin in tongue cancer.

Functional Observation of Skeletal Class III Patients Passed Long-Term after Retention

The goal of this study was to develop objective functional method of evaluating treatment systems for patients with jawdeformations, a treatment which is expected to increase in the future. We attempted to discern the characteristics of the recovery process ofpostoperative jaw motility and muscle function by studying preoperative and postoperative skeletal class III patients and comparing themwith normal controls, placing emphasis on factors outside the treatment period of the jaw deformation patients.Using skeletal class III patients as controls, we measured jaw movements and muscle function over a period extending beyond that of thesurgical orthodontic treatment, which includes the periods prior to initiation of the preoperative orthodontic treatment and aftercompletion of the retention.The following results were obtained;1) Orthognathic surgery not only corrected the form of the malocclusion, but is also improved the function of the masticatory system.2) A new masticatory form was essentially established by the maxillomandibular relationship created by the orthognasthic surgery.3) Masticatory function in the patients was an improvement over that before the operation, and was either as good as the function in personswith normal occlusion or better.4) Maintenance of the occlusion during the postoperative recall seemed an important factor in the process of recovery of masticatoryfunction.