Alteration of pRb expression in the development of rat tongue carcinoma induced by 4-nitroquinoline 1-oxide.

We investigated the immunohistochemical expression of Rb protein (pRb), which plays an important role in the regulation of the cell cycle, in rat tongue carcinoma induced by 4-nitroquinoline 1-oxide. In addition, we made an immunohistochemical investigation of cyclin D1 and cdk4, which are involved in the Rb pathway. The labeling index of pRb expression in cases with carcinoma was significantly decreased compared with that in cases with a premalignant lesion (P<0.01), while the labeling index of cyclin D1 and cdk4 increased gradually during the course of carcinogenesis. We analyzed the phosphorylation of pRb by immunoblotting using G3-245 monoclonal antibody, which recognizes both the phosphorylated and unphosphorylated forms of pRb. Although expression of the phosphorylated pRb band was notably increased in dysplastic membrane compared with the control membrane, it almost disappeared in cases with carcinoma. Unphosphorylated pRb bands were also expressed in control membrane and dysplastic membrane but not in cases with carcinoma. In conclusion, a decrease of pRb and an increase of cdk4 and cyclin D1 were shown to occur during the premalignant stage. The decrease of pRb in quantity and the increase of its phosphorylation may prevent G1 arrest and consequently accelerate proliferation of the chemically injured cells contributing to the initiation of carcinogenesis.

Correlation of E-cadherin and alpha-catenin expression with differentiation of oral squamous cell carcinoma.

The precise mechanism of disruption of cell-cell adhesion in oral squamous cell carcinomas has yet to be established. We therefore sought to clearly this mechanism by investigating expression of both E-cadherin (E-CD) and alpha-catenin (alpha-CAT), which is an intracellular CD-binding molecule, in squamous cell carcinomas of the tongue, gingiva and floor of the mouth using immunohistochemical and immunoblotting techniques. We found that reduced expression of both E-CD and alpha-CAT occurred more frequently in moderately- and poorly-differentiated carcinomas than in well-differentiated specimens (p < 0.001), and this reduced expression showed no regional specificity. Relatively frequent loss of alpha-CAT expression in poorly-differentiated carcinomas was detected by both immunohistochemical and immunoblotting analyses. These findings suggest that E-CD and alpha-CAT are both important regulators of intercellular adhesion, and that the reduction of these molecules is also linked to the process of tumor dedifferentiation.

Correlation of lining thickness and expression of alpha 2 and alpha 3 integrins within the epithelial lining of odontogenic cysts.

Using monoclonal antibodies, we performed immunohistochemical investigations of the expression of alpha 2, alpha 3 and beta 4 integrin subunits within the squamous epithelial linings of odontogenic cysts. Tissue samples consisted of both follicular cysts and odontogenic keratocysts from 15 patients. It was found that beta 4 integrin was expressed on the basement membrane regardless of the histological type of the cyst. The degree of immunostaining for alpha 2 and alpha 3 integrin expression corresponded to the thickness of the epithelial cyst wall. We found that the thickness of the epithelial lining of odontogenic cysts had a direct correlation with the expression of integrin molecules.

Chondroitin sulfate isomers in synovial fluid of healthy and diseased human temporomandibular joints.

Synovial fluid was collected from the superior articular cavity of the temporomandibular joint in patients with unilateral internal derangement and joint pain whose contralateral joint was healthy. Glycosaminoglycans were liberated by digestion with pronase E, and precipitated with cetylpyridinium chloride and ethanol. Unsaturated disaccharide isomers of chondroitin sulfate, obtained following chondroitinase ACII digestion, were analyzed by high-performance liquid chromatography. Analytic data indicated that deltaDi-0S and deltaDi-6S were often found in chondroitin sulfate from the fluid of the diseased joints. The amounts of deltaDi-0S and deltaDi-6S differed significantly between synovial fluid samples from the diseased and healthy joints. Comparison of the relative proportions of the unsaturated disaccharides in the synovial fluid with previously reported values for several tissues, indicated that the chondroitin sulfate originated from articular cartilage, with possibly some contributions from soft connective tissues and serum present in the synovial fluid. These results suggest that chondroitin sulfate in the synovial fluid provides a useful indicator of the degree of internal derangement of the temporomandibular joint.

Establishment and characterization of a human tongue cancer xenograft line in nude mice.

We established a human tongue cancer (well-differentiated squamous cell carcinoma) xenograft line, LK-1, in nude mice. LK-1 showed logarithmic growth from 5 to 7 weeks after transplantation, and the take rate for 25 generations was 95.0%. We confirmed the expression of cytokeratins 1, 5, 7, 10, 14, 16, 17, 18 and 19, and type I, III, IV and V collagens by electrophoretical and immunohistochemical analyses. Although the amount of type I, IV and V collagens increased gradually from 5 weeks after transplantation, the distribution of type IV collagen was often discontinuous in the cancer basement membrane. From these data we concluded that LK-1 is an excellent model for the investigation of the cell biology of well-differentiated oral squamous cell carcinoma, and for examining the effects of clinical therapies for this disease.

Immunohistochemical investigation of epidermal growth factor receptor expression in ameloblastomas.

Immunohistochemical analysis was performed to determine the localization of epidermal growth factor receptor (EGFR) in ameloblastomas. Ameloblastoma samples were classified into follicular, plexiform, and basal cell types. The number of cases in each category was 17, 19 and 3, respectively. Ameloblastomas, disregarding their histological type, consist of two cell forms: peripheral columnar cells and central stellate cells. The frequency of EGFR expression was much higher in the latter than in the former (P < 0.005). On analysis with respect to histological types, the frequency of EGFR expression in columnar cells was not significantly different between the follicular and the plexiform types, but was observed more frequently in the stellate cells in the follicular than in the plexiform ameloblastomas (P < 0.05). This pattern of EGFR expression was not consistent with the PCNA staining pattern, but was similar to that of keratin expression which we have reported previously. The present study suggests that EGFR expression in ameloblastomas is closely associated with tumour differentiation, and squamous differentiation in particular.

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

The expression pattern of two Ca(2+)-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 Ca(2+)-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. In the case of gingival carcinoma, although E-cadherin was strongly expressed in the cells surrounding the keratinized region in the cancer nests, the expression decreased towards the marginal portion of the cancer nests. The distribution of E-cadherin in these cells may be dependent on the condition of the cancer cells that are potentially invasive. These findings suggest that cells of the parakeratinized layer of gingiva and cells of the marginal portion of the gingival carcinoma nests may easily detach or invade. In addition, the findings suggest that the gingival carcinoma used in this study tended to be invasive.

Calcifying odontogenic cysts: co-expression of intermediate filament proteins, and immunohistochemical distribution of keratins, involucrin, and filaggrin.

The epithelia lining the cyst of five cases of calcifying odontogenic cyst (COC) were evaluated immunohistochemically with the use of monoclonal antibodies (MoAb's) against keratin (PKK1, KL1, K4.62, K8.12) and vimentin, and polyclonal antisera agonist involucrin and filaggrin. Epithelial lining of COC was classified into 1) thin squamous-cell epithelium, 2) ameloblastoma-like, and 3) thin or 4) thick calcifying odontogenic epithelium. Foci consisting of ghost cells or calcified cells were categorized as calcifying epithelial odontogenic tumor (CEOT). Thin squamous-cell epithelium reacted with PKK1, KL1, K4.62, K8.12, and anti-vimentin MoAb's, thus demonstrating the co-expression of keratin and vimentin. Ameloblastoma-like cells showed positive staining with PKK1, KL1, and sometimes with anti-vimentin. Thick calcifying odontogenic epithelial lining showed stratification of cell layers, and the most strikingly reactive zone was the upper intermediate layer, which showed the presence of keratin, involucrin, and a small amount of filaggrin. Cells of this layer might be the most differentiated type of cells in COC. Undifferentiated odontogenic cells of COC masses were characterized by co-expression of keratin and vimentin, and by the absence of involucrin and filaggrin. All ghost cells were devoid of any immunostaining except for filaggrin, which was rarely positive, but eosinophilic or basophilic cells surrounding the ghost cells showed intense staining for all keratin proteins except vimentin.

Application of video surgery to orthodontic diagnosis.

The purpose of this project was to develop a practical methodology for predicting the visual facial changes resulting from the movement of anterior teeth. The armamentarium includes an 8-bit audiovisual computer, a video camera, a digitizer, and a cephalogram of the patient. The system outputs the patient's profile on a personal computer video display. The image is superimposed on the soft tissue line of a digitized cephalogram plot on the same display. The video profile image is transformed from analog to digital signals. The profile image digitized by the computer is modified according to average ratios of soft tissue to hard tissue changes induced by modifications to the hard tissues. The program incorporates the spline function to smooth the profile image.

Prognostic evaluation of ameloblastoma based on histologic and radiographic typing.

Ninety-one patients with ameloblastoma of the mandible were studied. Among the 23 patients treated with radical surgery the recurrence rate was 8.7%, whereas the rate of 45.65% in the 68 conservatively treated patients. The prognoses of the patients treated by conservative surgery were analyzed based on the histologic and radiologic criteria of each lesion. The recurrence rate was significantly higher in the follicular type (56.8%) than in the plexiform type (32.3%). Recurrence was seen more frequently in the multilocular or soap bubble type (60.7%) than in the unilocular type (35.0%). When the recurrence rate was compared between patients aged less than 20 years and patients aged greater than or equal to 20 years, younger patients had better prognoses. It was concluded that there is a prognostic value in the histologic, radiographic, and age factors.

A clinicopathologic study of ameloblastoma.

One hundred four ameloblastomas, 97 in the mandible, five in the maxilla, and two in peripheral locations, were studied. A consistent correlation between the age of the patient and the radiographic or histologic type of mandibular ameloblastoma was observed. There was a tendency for ameloblastomas of the follicular type to show a multilocular or soap bubble appearance and for those of the plexiform type to show a unilocular appearance. Recurrent ameloblastomas had a predominantly multilocular appearance. Histologically, the ameloblastomas in the maxilla were of the follicular type.

Ultrastructural localization of alkaline phosphatase in the calcifying epithelial odontogenic tumor.

The localization of alkaline phosphatase in a calcifying epithelial odontogenic tumor obtained from a 53-year-old man was examined cytochemically. The majority of enzyme activity was associated with the epithelial cell membranes of the tumor, and faint activity was found in the cell membranes facing the adjacent stromal tissue. The reaction product of ALP was also detected in some membrane-bound vacuoles (lysosomes) and the Golgi apparatus of tumor cells. It is suggested that the appearance of enzyme activity associated mostly with the epithelial cell membrane may be related to transport function of cell membranes.