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A 13-month-old Japanese boy presented with painless swelling in a left mandible and cheek. Intraoral examination revealed swelling in the left mandible and hemorrhage of oral mucosa due to biting. CT images revealed a wide osteolytic lesion of the left mandible with floating teeth. Biopsy was carried out and histopathological diagnosis was discussed.

Important factors involved in odontogenesis in mouse dental papillae disappear between the pre- and post-natal stages of development. Therefore, we hypothesized that certain genes involved in odontogenesis in dental papillae were subject to pre-/post-natal down-regulation. Our goal was to identify, by microarray analysis, which genes were down-regulated. Dental papillae were isolated from embryonic 16-day-, 18-day- (E16, E18), and post-natal 3-day-old (P3) murine first mandibular molar germs and analyzed by microarray. The number of down-regulated genes was 2269 between E16 and E18, and 3130 between E18 and P3. Drastic down-regulation (fold change > 10.0) of Adamts4, Aldha1a2, and Lef1 was observed at both E16 and E18, and quantitative RT-PCR revealed a post-natal reduction in their expression ( Adamts4, 1/3; Aldh1a2, 1/13; and Lef1, 1/37). These results suggest that down-regulation of these three genes is an important factor in normal odontogenesis in dental papillae.

Oral Diseases (2010) 16, 263–268 Objective: The aim of this study was to investigate the proliferation, migration and death of periodontal ligament (PDL) cells after tooth replantation. Materials and methods: Maxillary first molars were extracted from 4-week-old male (n = 28) Sprague–Dawley rats and immediately replanted, after which, proliferation, migration and death of PDL cells were investigated. Results: At 3 days after tooth replantation, many proliferative cell nuclear antigen (PCNA)-positive PDL cells were observed on the alveolar bone side, but fewer on the root side. However, while a gradual decrease was observed in number of PCNA-positive PDL cells on the alveolar bone side until 7 days, an increase was seen on the root side. At 3 weeks, cells labeled with PKH26 (fluorescent dye into plasma membrane) were located in the middle of the PDL space. However, these PKH26-labeled cells did not spread to the surface of the cementum or the alveolar bone. TUNEL-positive cells were observed on both the bone and root sides at 3 days. Number of apoptotic cells increased until 7 days on the bone sides, but decreased on root sides. Conclusion: These results suggest that both cell proliferation and apoptosis occur in different patterns and at different times to maintain regular spacing of the PDL after tooth replantation.

Background and Objective: The 4-META/MMA-TBB [4-(2-methacryloxyethyl)trimellitic anhydride/methyl methacrylate-tributylborane] resin is widely used as a dental adhesive. It has also been applied in the dressing of gingival wound surfaces following periodontal surgery. However, its effect on the regeneration and/or cell attachment of the oral epithelium remains to be clarified. To evaluate the effect of the resin applied as a wound dressing, we investigated expression of laminin 5, integrin β4 and cytokeratin 14 in regenerating oral epithelium treated with this resin following gingivectomy from the viewpoint of cell attachment and differentiation. Material and Methods: The resin was applied to the entire wound surface in rats after gingival surgery, and regenerating epithelium was examined immediately and at 1, 3, 5, 7 and 14 days later. The resin was removed 2 weeks after application in some animals and tissue further examined at 1, 3, 5 and 7 days later. Results: Regenerating epithelium under the resin was not keratinized, but became keratinized immediately after removal of the resin. Laminin 5 and integrin β4 were immunolocalized in the basal lamina, the internal basal lamina, in marginal cells of the regenerating epithelium and at the resin–regenerating epithelium interface. Cytokeratin 14 localized in the regenerating epithelium underneath the resin, as well as in healthy and regenerated junctional epithelial cells. Conclusion: These results suggest that this resin covers the wound surface and that the regenerating epithelium biologically adheres to the resin during the initial process of its regeneration.

Background and objective The junctional epithelium attaches to the enamel surface with hemidesmosomes (of which laminin-5 and integrin-alpha(6)beta(4) are the main components) in the internal basal lamina. Laminin-5 is also involved in cell motility with integrin-alpha(3)beta(1), although their functions have not yet been clarified.The purpose of this study was to determine the functions of those adhesive components between the tooth and the junctional epithelium during cell migration.Because an idea has been proposed that directly attached to tooth cells (DAT cells) may not contribute to cell migration, 5-bromo-2-deoxyuridine staining was performed to confirm cell migration. Material and methods We investigated laminin-gamma(2) (contained only in laminin-5), integrin-beta(4) (involved in cell-extracellular matrix contact) and integrin-alpha(3) (inducing cell migration) in the junctional epithelium, oral gingival epithelium and gingival sulcus epithelium of 6-wk-old ICR mice using laser microdissection, quantitative real-time reverse transcription-polymerase chain reaction, immunofluorescence and 5-bromo-2-deoxyuridine staining. Results Laminin and integrins were clearly immuno-localized in the basal lamina of all epithelium. Quantitative analysis of laminin and integrin mRNAs by laser microdissection showed that they were more highly expressed in DAT cells than in basal cells in the oral gingival epithelium. In particular, a 12-fold higher expression of laminin-5 was observed in the junctional epithelium compared with the oral gingival epithelium. 5-Bromo-2-deoxyuridine staining showed rapid coronal migration of DAT cells. Conclusion These results suggest that the abundant expression of laminin-5 and integrin-alpha(6)beta(4) is involved in the attachment of DAT cells to teeth by hemidesmosomes. Abundant expression of laminin-5 and integrin-alpha(3)beta(1) might assist in DAT cell migration, confirmed by 5-bromo-2-deoxyuridine staining during the turnover of junctional epithelium.

Temporomandibular disorders are a group of chronic and painful conditions in the masticatory musculature and temporomandibular joint. The pathological mechanisms underlying temporomandibular disorders remain to be clarified; however, it is known that disturbances in neurophysiological, cognitive, behavioral and neuromuscular functions are involved in the development and persistence of such disorders. In addition, it has been suggested that neuropathological changes in the central nervous system are involved in the development of temporomandibular disorders. This review describes changes in the cortical machinery in patients with temporomandibular disorders by comparing neuromagnetic signals between healthy subjects and patients elicited by observing jaw opening movements made by another person.

Many morphological and developmental studies have demonstrated the characteristics of tight junctions (TJs) between odontoblasts. However, detailed localization of TJ-associated proteins in odontoblasts and their functions has not yet been clarified. To elucidate the relationship between the establishment of TJ structures and the differentiation of odontoblasts during early dentinogenesis, we studied the expression and localization of constituent proteins of TJs (claudin-1, occludin, ZO-1 and ZO-2) between odontoblasts in rat lower incisors using Western blotting, immunofluorescence and immunoelectron microscopy. When the expression of claudin-1 increases at the distal portion of mature odontoblasts, the TJs form complex networks of strands, and odontoblasts differentiated by developing distal membrane domains and by secreting specific molecules for mineralization. We conclude that the TJs of odontoblasts may play an important role in the differentiation of odontoblasts in rat lower incisors during early dentinogenesis.

The regeneration of wounded stratified epithelium is accomplished via the migration of keratinocytes from the margins of the wound. However, the process of keratinocyte migration on the wound surface and the role of epithelial stem cells during re-epithelialization remain to be elucidated. Therefore, we administered BrdU to embryonic mice and generated epithelial defects on the buccal mucosa of these mice at two weeks after birth, using CO(2) laser irradiation, with which we removed the entire thickness of the epithelium. In the unwounded epithelium, cytokeratin 14, p63, and BrdU were localized within the basal layer of the epithelium, but the majority of cells within the regenerated epithelium were immunopositive for these proteins. PCNA-negative and BrdU-positive basal keratinocytes, which evidence a slow cell cycle, were localized solely within the basal layer of the unwound epithelium facing the tips of dermal papillae. After laser irradiation, these basal keratinocytes facing the tips of the papillae evidenced positive immunoreactivity for PCNA, in addition to BrdU. These results indicate that epithelial stem cells of oral mucosa may be localized in the basal layer of the epithelium facing the tips of dermal papillae, and may migrate laterally with other basal keratinocytes in response to external stimuli.

The submandibular gland (SMG) is a tissue that can be regenerated in a tissue injury model and that has adult stem cells capable of self-renewal and differentiation into functional cells. We have analyzed the localization of label-retaining cells (LRCs), which are putative progenitor cells, by using the BrdU-labeling method. 5-Bromo-2'-deoxyuridine (BrdU) injection followed by a long chasing period permitted the identification of LRCs based on the slow-cycling characteristic. In order to confirm the accurate localization of LRCs, BrdU and SMG-specific markers, including aquaporin5, cytokeratin, and smooth muscle actin, were examined by double-immunofluorescence staining. We found that LRCs were distributed in the acinus, duct, myoepithelium, and connective tissue. Moreover, ABCG2 (a known stem cell marker) was used for the characterization of LRCs and the localization of cells as putative stem/progenitor cells. ABCG2-expressing cells were distributed in various regions of the SMG but did not co-localize with LRCs. We suggest that putative progenitor cells exist in various regions of the SMG and have diverse capacities to differentiate into specific cells.

A rare case of hepatocellular carcinoma (HCC) that metastasized to the posterior mandible of a 74-year-old Japanese female is described. Computed tomography (CT) revealed buccolingual osteolytic masses. Histopathologically, the solid tumor nests were composed of cells with granular eosinophilic cytoplasm, oval nuclei and enlarged nucleoli. Immunohistochemically, the tumor cells were strongly positive for hepatocyte paraffin 1 (Hep Par 1) and cytokeratin 18 (CK18). Ultrastructurally, abundant mitochondria, rough endoplasmic reticulum, lysosome-like granules, ductal structures and intercellular junctional complexes were distinct in the tumor cells. At autopsy, multinodular tumor masses and cirrhosis were detected in the liver. Microscopically, the tumor cells had trabecular, solid and sarcomatous appearances with severe atypism. Metastatic foci were found in the spleen, stomach, lymph nodes and ribs, but not in the lungs. We finally diagnosed this as mandibular metastasis of HCC, which is a very rare cancer, 1 of only 5 known cases in a female.

Background: Osteopontin (OPN) expression in squamous cell carcinoma (SCC) of the tongue has not been clearly elucidated. Methods: We selected 46 cases of tongue SCC and investigated the expression of OPN by immunohistochemical staining. The immunopositive reaction and score for each case were semiquantitatively evaluated. Results: Scores were significantly higher in carcinoma nests than in neighboring normal epithelium or epithelial dysplasia. The OPN was expressed clearly in the cytoplasm of carcinoma cells. In cases of early invasive carcinoma, in particular, expression of OPN showed a remarkable increase at the invasion front compared with the non-invaded regions. However, there was no significant correlation between expression of OPN in the primary tumor nest and lymphatic metastasis, recurrence, or survival rate. Conclusion: This suggests that OPN is a useful biomarker of early invasion by SCC in tongue.

Background and Objective: It is known that epithelial islands are embedded in the cementum during tooth root formation, but details of this process remain unknown. The purpose of this study was to investigate the dynamic characteristics of Malassez's epithelial rest cells in the cementum during tooth root formation in pigs in vivo. Material and Methods: The first molars of 6-mo-old pigs were used in this study. Specimens were decalcified before being embedded in paraffin. Paraffin sections were investigated using TdT-mediated dUTP-biotin nick end labeling (TUNEL), immunohistochemical, and ultrastructural techniques. Results: Malassez's epithelial rest cells were located close to the root surface at the apical one-third of the periodontal ligament, and epithelial clusters surrounded by distinct lamina cementia were sometimes observed in the cementum. TUNEL-positive cells were detected only in the cementum. Malassez's epithelial rest cells in the periodontal ligament were completely surrounded by basement membranes, but epithelial clusters in the cementum were only intermittently surrounded by such membranes. Cytokeratin-positive cells in the superstratum of the cementum were directly connected by cementocytes and by desmosome-like structures. However, organelles were scarce in the cytokeratin-positive cells in the substratum of the cementum, and the matrix of the cementum was deposited in the cells. Conclusion: These results suggest that the majority of the fragmented Hertwig's root sheath remains in the periodontal ligament and that some cells, which are connected to cementoblasts, are embedded in the cementum and progress to apoptosis.

We examined expression of syndecan-1 in squamous cell carcinoma (SCC) of tongue using immunohistochemistry. Forty-three cases of SCC arising in lateral border of tongue were investigated. From the immunohistochemical staining pattern, the cases were divided into two groups based on expression of syndecan-1 at the supra-peripheral cells of the tumor nest: Group A, completely or mainly positive; Group B, sporadically positive or negative. Most poorly differentiated SCC cases were classified into Group B (81.8%). The number of Group B cases in T1-2 was different from that in T3-4. The number of cases where syndecan-1 expression was reduced was much greater in T3-4, and represented the majority of Group B (86.7%). More than 80% of Grade 4D cases were in Group B (83.3%) based on the Yamamoto-Kohama criteria. These results indicate that reduction of syndecan-1 correlates to histological grade, tumor size and mode of invasion in tongue SCC.

Laminin-5 (Ln-5) is an important molecule associated with epithelial cell adhesion and migration. In the gingiva around the tooth, Ln-5 localizes within basement membranes between the junctional epithelium (JE) and the tooth or connective tissue. Recently, we reported that in the oral mucosa around a dental implant, Ln-5 is expressed within the basement membranes at the implant-peri-implant epithelium (PIE) interface, and at the PIE–connective tissue interface. However, the ultrastructural localization of Ln-5 within or along the PIE has not yet been reported. Therefore, peri-implant oral mucosa was treated with anti-Ln-5 ( γ 2 chain) antibody and examined using immuno-electron microscopy. Ln-5 was localized in the cells of the innermost-third layer and basal layer of the PIE. A 100-nm-wide Ln-5-positive internal basal lamina (basement membrane) and hemidesmosomes as adhesion structures were formed at the apical portion of the implant–PIE interface. However, at the upper-middle portion of the interface, these adhesion structures were not observed. Furthermore, at the PIE–connective tissue interface, the Ln-5-positive external basal lamina (basement membrane) and hemidesmosomes were partially deficient. Judging from these findings, we concluded that Ln-5 contributes to the attachment of the PIE to the titanium surface, and that PIE attached to titanium at the apical portion of the dental implant–PIE interface.

A 57-year-old man was referred to our hospital because of a lump of his lateral neck region. Aspiration and intraoperative biopsies were performed to confirm the pathological diagnosis. The tumor showed a neoplastic epithelium arranged in a ductal or follicular pattern with papillary proliferation, and tumor cells were immunohistochemically positive for thyroglobulin. The pathological diagnosis was papillary thyroid carcinoma metastasis to a lymph node in the lateral neck region. Metastases were also observed in other lymph nodes in the submandibular region, and multiple metastatic foci were later found in the lungs and brain. Heavy ion radiotherapy was performed to extend the patient's life.

Background and objective: It is still an open question why long junctional epithelium can proliferate and occupies the root surface following periodontal surgery or experimentally produced periodontitis, and why the epithelium repopulated once on the root surface is replaced by the connective tissue. The aim of this study is to investigate the proliferative activity of the newly formed regenerative connective tissue and long junctional epithelium during wound healing by staining argyrophilic proteins of the nucleolar organizer regions (AgNORs). Methods: Regenerative connective tissue and long junctional epithelium were experimentally created by insertion of a rubber piece between maxillary molars of rats for 1 week. After removal of the rubber, AgNORs parameters including nuclear area (NA), AgNORs area (AA), AgNORs percentage nuclear area (APNA), AgNORs number (AN) and nuclear number (NN) in regenerative connective tissue and long junctional epithelium were measured and analyzed statistically. Results: APNA in long junctional epithelium after 1 and 4 weeks was over two times greater than that in the regenerative connective tissue. AA in long junctional epithelium was significantly higher than in regenerative connective tissue at 1 and at 4 weeks post-treatment. AN was higher in the central portion than at the root surface except at 20 weeks. APNA and AA decreased remarkably in long junctional epithelium at 12 weeks post-treatment (approximately half at 4 weeks), whereas in regenerative connective tissue, they did not change distinctly. Conclusions: These results imply that long junctional epithelium cannot supply sufficient epithelial cells because of their significantly low rates of proliferation, consequently long junctional epithelium becomes shorter after 12 weeks, whereas the proliferative activity of regenerative connective tissue maintains the same level of proliferation, and ultimately long junctional epithelium is replaced by regenerative connective tissue.

The purpose of this study was to investigate the relationship between epithelial dysplasia unstained with iodine and the expression of proliferating cell nuclear antigen (PCNA) and/or tumour suppressor gene (p53) and the existence of glycogen. Thirty cases of squamous cell carcinomas arising from the buccal mucosa and floor of the mouth were examined. Iodine unstained areas were diagnosed histopathologically as mild, moderate or severe epithelial dysplasia. Normal oral mucosa stained with iodine was used as a control group. There was no histochemical difference in the distribution or ratio of PAS-positive cells between the control and the mild epithelial dysplasia groups, however PAS stained areas of the moderate and the severe dysplasia groups were significantly decreased. Ultrastructurally, glycogen granules were not recognized in the moderate or severe dysplastic epithelia. Immunoreactive ratios of PCNA and p53 in the moderate and severe dysplastic groups were significantly higher than those of the control and the mild dysplasia groups. The positive ratio of PCNA was higher than that of p53, although the immunostaining patterns of PCNA- and p53-positive cells were quite similar. These results suggest that mild dysplastic epithelia that are stained with iodine may be in the category of normal epithelia, whereas both moderate and severe dysplasia that are un-stained with iodine may be suspected of malignant lesions.

Cementoblastoma is a relatively rare type of odontogenic tumor. This study investigated the features of cementoblastoma tumor cells in three cases using immunohistochemistry. Immunopositive reactivity for Ki-67 was recognized in the nuclei of spindle-shaped cells that were located in the fibrous connective tissue among the cementum-like hard tissue. Those cells were mainly discernible at the periphery of the tumors. Polygonal cementoblast-like cells with large nuclei surrounding the hard tissue were immunopositive for osteopontin and osteocalcin but not for Ki-67, which suggests that these cells may be more differentiated cells that have the potential to form hard tissue.

This case report describes a rare case of canalicular adenoma arising in the upper lip of a 61-year-old male patient. Macroscopic examination of the tumor revealed a well-defined, smooth, firm, elastic hard, round nodule with a diameter of 1.0 cm. The cut surface was white. Histopathology showed that the tumor was an encapsulated mass with a complex cellular pattern of anastomosing duct-like or trabecular structures lined by a single layer of tall columnar epithelial cells, which were embedded in a loose, fibrous, and highly vascular connective tissue stroma. The tumor cells were immunoreactive to AE1/AE3, CK19 and S-100, were partially positive for CK7, CK8, GFAP and PCNA, but were negative for SMA, CK13, CK14 and vimentin.

We report a case of oncocytic carcinoma arising in submandibular gland. The tumour occurred in the left submandibular gland of an 82-year-old Japanese man. Histologically, the tumour was mostly composed of large cells with eosinophilic granules in the cytoplasm and they were arranged in the solid sheets, islands with duct-like structure and cords. The tumour cells had aggressively invaded muscles and perineural tissues, and cervical lymphatic metastasis was frequently observed. Histochemically, the tumour cells were strongly positive for phosphotungstic acid-hematoxylin (PTAH) stain, and we diagnosed this malignant tumour as oncocytic carcinoma. Immunohistochemically, the tumour cells reacted positively for cytokeratin 7, 8, 19, epithelial membrane antigen (EMA), alpha-1-antichymotrypsin and carcinoembryonic antigen (CEA), but negative for cytokeratin 13, 14, smooth muscle actin (HHF35) and S-100 protein (S-100). Tumour was diagnosed as oncocytic carcinoma in submandibular gland. Its characteristics are discussed in term of its histopathological and immunohistochemical features.

We report a rare case of a papillary cystadenoma arising from the upper lip. This tumor was not distinctly encapsulated and had proliferated replacing the ductal epithelium. Mast cells were found not only in the stroma but also in the oncocytic epithelial layer. There was a strong immunoreaction with mitochondrial antibody in the epithelial layer. Only one case (0.9%) of papillary cystadenoma has occurred among the 110 benign intraoral salivary gland tumors seen in our hospital from 1966 through September 2003.

The purpose of this study was to investigate the immunohistochemical and the ultrastructural features of the implant circumference epithelium of the beagle dog using various types of antibodies. The peri-implant epithelium was at an acute-angle from the gingival epithelium and was arranged in parallel to the implant surface. With immunohistochemical staining, the peri-implant epithelium was strongly positive for KL-1, and weakly positive for CK4, CK8 and CK19. These positive reactions for keratins and also for PCNA and BM-1 were similar to those seen in the oral mucosa. In the peri-implant epithelium, a plentitude of microvilli were observed at the periphery of cells at the implant sites, and bacteria were observed between the implant and the peri-implant epithelium without the formation of half desmosomes. There were many lipid-like vacuoles or lysosome-like granules. The intercellular space was wider than the junctional epithelium, and random migrations of large numbers of neutrophils could be seen. Taken together, the peri-implant epithelium is similar to that seen in the oral mucosa, and it is structurally different from the junctional epithelium.

The behavior of epithelial cells during tooth root formation in porcine molars was investigated using TUNEL, immunohistochemical and transmission electron microscopic methods. Cells of Hertwig's epithelial root sheath (HERS) expressed bcl-2, but were TUNEL-negative. Epithelial cells of HERS were tightly connected and surrounded by a continuous basement membrane. When dental papilla cells were attached to the inner HERS, they became positive for osteopontin (OPN). The inner basement membrane was intermittent immediately after those cells started to synthesize dentin matrix, and the intercellular spaces of the HERS became wider. Dental sac cells then migrated between the fragmented HERS and were directly connected to epithelial cells by desmosome-like structures. After the cementum was synthesized by these mesenchymal cells, epithelial cells aggregated to form cell clusters, which were again surrounded by a continuous basement membrane. These results suggest that fragmentation of the HERS is due to the invasion of dental sac cells, but is not related to cell death. Furthermore, the differentiation of dental papilla cells into odontoblasts occurred following their connection to the HERS through the basement membrane. Moreover, it is suggested that the differentiation of dental sac cells into cementoblasts occurred upon their direct connection to epithelial cells of the HERS.

In the present study, we investigated the localization of amelogenin in odontogenic tumors, using an anti-amelogenin polyclonal antibody. In order to make the antibody, antisera against an amelogenin fraction obtained from the enamel matrix of unerupted bovine tooth was raised in rabbits. By Western blot analysis, a main band of 25 kDa and six minor bands (6.8, 12, 18, 20, 23, and 27 kDa) were detected under nonreducing conditions. Immunoreactivity for the amelogenin was observed in ameloblasts and in the immature enamel matrix of 4-day-old rats. In odontogenic tumors, positive reactions for amelogenin were localized in limited areas in adenomatoid odontogenic tumor, calcifying odontogenic cyst, primary intraosseous carcinoma and odontoma. The strongest immunoreactions were shown in enamel matrices in odontomas. Small mineralized foci in epithelial nests showed positive reactions, and a few reactions were observed in epithelium adjacent to the mineralized foci. In calcifying odontogenic cysts, some ghost cells in the lining epithelium were strongly stained. The results indicate that the present antibody for amelogenin is useful for the determination of odontogenic tumors, especially in those in which small mineralized foci are present in the epithelilal nests.

This case report describes an ameloblastic fibro-odontoma arising from a calcifying odontogenic cyst (COC) in the mandible of a twenty-three-year old male. The patient was referred to the Department of Oral Surgery, Tokyo Dental College, on March 30th, 2000, complaining of a painful swelling, which had appeared three weeks earlier on his left mandibular molar region. In a pathological view, the lesion was a round cyst the size of a chicken-egg, dark red in color, and surrounded by a thick membrane. The cyst had an epithelium of varying thickness which included many ghost cells and an enamel-like structure on the inside, and a thick wall of connective tissue with an ameloblastic fibro-odontoma on the outside. Enamel organ-like epithelial islands were structured radially in the form of strands with immature dentin. Cytokeratin 19 was strongly immunoreactive in the epithelium of the lesion; osteopontin and osteocalcin reacted in the mesenchymal cells and weakly in the epithelial element of this tumor.

The role played by the internal basal lamina (IBL) and hemidesmosomes between an implant and the peri-implant epithelium (PIE) in the adherence of the epithelium to the implant is controversial. This study used rat maxilla implantation models to clarify the ultrastructure of the PIE-implant interface.Ti-6Al-4V implants were inserted either immediately or 2 weeks after the extraction of the upper left first molar of 6- or 4-week-old rats, respectively. The junctional epithelium (JE) of the upper right molars in the same animals was used as a control. Four weeks after implantation, the animals were sacrificed to prepare specimens for light and immunoelectron microscopy.Under light microscopy, the PIE appeared to attach to the implant surface. Ultrastructurally, IBL, consisting of the lamina densa and lamina lucida, and hemidesmosomes were formed only in the lower region, and rarely in the middle region, of the PIE-implant interface. In control teeth, the IBL and hemidesmosomes formed throughout the dento-JE interface. Laminin-1 was found in the IBL and also in the vesicles and vacuoles of the PIE and JE cells. Statistical analysis showed that there was also a significant difference in the amount of IBL between the PIE-implant and dento-JE interfaces.PIE attached to the implant via hemidesmosomes and IBL in the lower region of the PIE-implant interface. Although PIE cells may secrete laminin-1, which contributes to epidermal cell adhesion, the PIE which attaches to implants only in the lower region of the interface is considered to be the poorly adhered epithelium.

Human β-defensin (hBD)-1 and hBD-2 are antimicrobial peptides that have been detected in certain types of epithelia, including the skin and oral epithelia. It has been suggested that bacterial infection is an important factor in the process of carcinogenesis. The expression of hBDs in oral squamous cell carcinoma (SCC) may be down-regulated. We studied the pattern of expression of hBD-1 and hBD-2 mRNA in oral (SCC) cell lines and in tumor samples obtained from four patients with oral SCC who underwent surgical resection, by reverse transcription-polymerase chain reaction (RT-PCR). Human gingival epithelial (HGE) cells were used as the control. The effect of various inflammatory cytokines on hBD-1 and hBD-2 expression in the HGE cells and SCC cell lines, was also studied. hBD-1 mRNA was detected in the Ca-9, SCC-9 and HSC-4 cell lines, but not in the SAS and KB cell lines. hBD-2 mRNA was detected in all five cell lines. All four tumor samples expressed both hBD-1 and hBD-2 mRNA, although the mRNA level of each protein varied. These results indicate that SCCs in which hBD expression is downregulated, may be susceptible to bacterial infection.

Pleomorphic adenomas with a nuclear palisading arrangement of spindle-shaped modified myoepithelial cells (MMCs), suggesting the appearance of palisading leiomyoma or Antoni's A type of neurilemmoma, are quite rare, and its cytologic nature has been poorly understood. This paper reports histologic and immunohistochemical findings of palisading MMCs in two cases of pleomorphic adenoma. Histologically, foci of spindle-shaped MMCs with nuclei in a palisading arrangement were scattered in the myxoid areas. Near the large foci of spindle-shaped MMCs with nuclear palisading arrangements, tiny foci of spindle-shaped MMCs forming nuclear palisading or rosette-like arrangements were seen. Such nuclear palisading arrangements of MMCs were suggestive of differentiation or transformation of MMCs into cells that were more smooth muscle in nature, supported by occasional existence of palisading leiomyoma in the myometrium and gastrointestinal tract. However, immunohistochemical findings of palisading MMCs in pleomorphic adenoma were similar to those of non-palisading MMCs, and showed no evidence of smooth muscle differentiation; neither palisading nor non-palisading MMCs in pleomorphic adenoma expressed desmin, muscle specific actin (HHF-35), alpha smooth muscle actin, or myoglobin. The biologic significance and formative mechanism of nuclear palisading arrangement of MMCs in pleomorphic adenoma could not be determined in the present study. However, if the MMCs with nuclear palisading arrangements in pleomorphic adenoma, presented here, are aspirated for cytologic diagnosis or are included in a small biopsy specimen, the correct diagnosis of pleomorphic adenoma may be confused by a suspicion of myogenic or neurogenic tumor.

We investigated the distribution and localization of connexin 26, 32, and 43 in rat parotid glands. Immunofluorescence microscopy revealed the presence of spots reacting for connexin 26 and 32 between endpiece cells. A few spots indicating connexin 43 occasionally were observed in the parotid glands. Connexin 43-positive spots were localized around intercalated ducts. No positive spots for these connexins were detected between ductal cells. Double immunofluorescence microscopy revealed that connexin 26-reactive sites could be observed within the same spots as connexin 32. Double immuno-electron microscopy confirmed that connexin 26 and 32 were co-localized in the same gap junction. These results suggest that connexin 26 and 32 are associated with secretory function and permeability between endpiece cells and that connexin 43 is associated with contraction of the myoepithelial cells that surround intercalated ducts in the rat parotid glands.

We investigated the occurrence of apoptosis and other types of cell death around the crown during tooth eruption of the rat upper molar. The TdT-mediated-dUTP-biotin nick end labeling (TUNEL) method and transmission electron microscopy (TEM) were employed. Apoptosis was detected by both TUNEL and TEM in part of the reduced enamel epithelium and connective tissue in the resorbing bony crypt of the pre-erupted tooth. In TEM, a large number of cells showed condensed chromatin and membrane-bound small bodies (apoptotic bodies). Macrophages that phagocytosed apoptotic bodies could be detected. Based upon the distance between bone surface and these apoptotic cells, and the characteristics of their organelles, we suggested that the apoptotic cells might be osteocytes, bone-lining cells (osteoblasts), and macrophages. We surmised that the osteoclasts had also died. Cells which contained autophagic vacuoles and autophagosomes, and others whose cytoplasm had dissolved, were also frequently observed. No progressive cell death was found in the oral epithelium or the fibrous connective tissue over the crown. These results suggest that apoptosis gives rise to some cell death during tooth eruption, but that other types of cell death also occur in various cells.

In the present study, we examined to identify down-regulated genes between pre- and post dental papillae by microarray analysis in order to identify genes involved in tooth morphogenesis.The dental papilla tissues obtained from E16, E18, P03 and P10 of ICR mice were used for microarray analysis. Microarray analysis showed that the number of up-regulated genes ranged from 860 to 2214 from E16 to P10 and was decreased following the tooth morphogenesis. On the other hand, the number of down-regulated genes ranged from 1337 to 2924, and number of down-regulated genes was the highest (2924 genes) during E18 and P3. The results suggest that the reduced or disappeared genes in dental papilla between P0 and P3 are associated with forming and calcifying the dentin of tooth crown and regeneration of tooth.

A rare case of clear cell odontogenic carcinoma was investigated using histochemical and immunohistochemical methods. The tumor occurred in the anterior mandible of a 69-year-old Japanese man. Histologically, the tumor was composed mostly of large clear cells and squamous cells. Columnar-shaped cells with basophilic nuclei polarized away from the basement membrane were observed at the periphery of the tumor foci. The tumor cells had aggressively invaded muscle and perineural tissues. The tumor cells were positive for PAS staining. Immunohistochemically, tumor cells reacted positively to keratin, cytokeratin19, epithelial membrane antigen, and S-100 protein. The tumor was diagnosed as a clear cell odontogenic carcinoma. Its characteristics are discussed in term of its histopathological, histochemical and immunohistochemical features.

The purpose of this study was to establish the criteria for oral epithelial dysplasia (OED). A total of fifty-six biopsies of white lesions in the buccal mucosa and gingiva were classified into Type I, II and III, and their relationship to expression of PCNA or p53 and keratinization patterns were examined. The appearance of PCNA positive cells coincided with severe atypia in the basal layer. p53 expression revealed focal, diffuse and basal layer patterns. The focal pattern was found in only Type I; both the diffuse and basal layer patterns were seen in Type II. All the cases of Type III showed the basal layer pattern. It is suggested that p53 expression of the basal layer pattern is useful for estimating the malignant potency. Parakeratosis demonstrating a tendency toward severe atypism and general disturbance is an important malignant sign.

We report a rare case of a completely isolated hemangioma with the histological findings of an arteriovenous hemangioma which occurred in the tongue of a 42-year-old female. This lesion was completely encapsulated by fibrous connective tissue and had focally proliferated with extensive vascular development. The tumor showed a lobular arrangement of vessels of generally uniform wall thickness. Vessel walls were stained by EVG and were immunohistochemically stained with SMA. Mast cells reactive for toluidine blue staining were frequently identified in the stroma and in the surrounding vascular area.

ビーグル成犬の前臼歯歯根膜内をセメント質領域, 中央領域および歯槽骨領域に三等分し細胞密度および分布について, PKK-1とPCNAを抗体とした免疫組織化学的検索を行った。細胞密度は, セメント質領域で他の部位に比べ有意差をもって多く観察された。血管の占有面積率では, 歯槽骨領域が他の部位に比べ有意差をもって高い値を示していた。増殖細胞の指標となるPCNAに陽性を示す細胞は, 中央領域で他の部位に比べ有意差をもって高い値を示し, 中でも血管周囲に位置したものが多かった。マラッセ上皮遺残はセメント質領域のみにみられ, 占有面積率で約2.32%を占めていた。以上の結果より, セメント質側の細胞の代謝回転は歯槽骨側のそれに比べ非常に活発であることが示唆された。また歯根膜内の芽細胞の供給は血管周囲の細胞から行われ, マラッセの上皮遺残は歯根膜腔の恒常性を調節する可能性が示唆された。

口腔扁平上皮癌剖検例10例について, 免疫組織化学的検討を行った。症例は, 男性5例, 女性5例で, 年齢は39～88歳, 原発部位は頬粘膜4例, 舌3例, 上顎2例, 軟口蓋1例で, 病期分類はstage II1例, III2例, IV7例であった。治療法は, 外科+放射線療法5例, 外科+放射線+化学療法4例, 放射線+化学療法1例で, 生存期間は7か月～38年であった。高分化型4例, 中分化型4例, 低分化型2例で, 細胞異型および構造異型は8例で認められた。浸潤様式は2型, 3型各1例, 4C型5例, 4D型3例であった。間質反応のリンパ球浸潤の程度は, 認められないもの3例, 軽度6例, 高度1例であった。CEAとkeratinは, 全例陽性であったが, その局在は症例により差がみられた。SCCは, 低分化型の1例を除き, 全例陽性であった。SCC, CEA, ケラチンの局在は腫瘍細胞の分化の程度を示す指標となると思われた。

A case of adenoameloblastic odontoma in the maxillary anterior region was reported. The patient, a 19 year-old woman, complained of occlusal pain at 2.In the first medical examination, swelling was admitted at 1-3 labial and palatal gingiva region.Radiograph showed a clearly demarcated radiolucent lesion at 2 In pulp test, 2 was non-vital, and 13 were vital.We performed enucleation and apicoectomy of 23.The tumor had a well defined fibrous capsule, so we easily removed the tumor.The tumor, presented globulary, was measured in a region of about 16 mm which included hard tissues.Microscopically, this tumor was encapsulated with thin fibrous tissues.The calcified tissues and odontogenic epithelia could be observed in the tumor.The calcified tissues were analogous to odontoma which contained regular and irregular dentinal tubules. The odontogenic epithelia revealed various patterns, i.e.sheet-like, adenomatoid and follicular struc tures.The adenomatoid structures were composed of cuboid cells, and the pscudoluminal region was occupied by fine fibrous materials.The present case was pathologically diagnosed as adenoameloblastic odontoma.6 months have passed, and there have been no symptoms of recurrence.

同一ラットの歯髄, 歯根膜, 骨髄, 筋肉および皮下結合組織を骨基質, 象牙質基質および脱灰骨基質, 脱灰象牙質基質上で培養した時の新生骨形成ないし新生軟骨誘導能を検索した。新生骨様組織の形成は, 骨基質および象牙質基質上で観察され, 歯髄より遊出した細胞で最も多く次いで歯根膜, 骨髄の順であった。しかしながら, 筋肉と皮下結合組織より遊出した細胞には新生骨の形成は見られなかった。また, 石灰化に関しても骨新生同様の結果が得られた。軟骨の誘導は, 脱灰骨基質および脱灰象牙質基質上で主として筋肉より遊出した細胞のみに見られ, 他の細胞には観察することが出来なかった。これらの結果より, 歯髄, 歯根膜, 骨髄などの硬組織形成性結合組織の細胞は, 骨誘導蛋白 (BMP) に対して軟骨細胞への分化因子としては, 反応しにくいことが示唆された。

Eosinophilic granuloma of soft tissue mainly appeares as a tumor-like nodule in the subcutanous head and neck region. Histopathologically, it is characterized oy the presence of lymphoid follicles, and marked infiltration of eosinophils, as well as fibrosis and vascular proliferation.We reported 4 cases of cosinophilic granuloma of soft tissue in the parotid-massetcr region, inferior surface of the tongue and buccal region. We obtained successful results by surgical procedures and/or radio therapy.

Carcinoma in pleomorphic adenoma is a relatively rare lesion, and a case of which is reported in this article.A 52-year-old man had become aware of painless swelling in the right parotid gland about 15 years before. Because the swelling became larger, the patient was admitted to Tokyo Dental College Ichikawa Hospital. The Surgically removed tumor was examined using a light microscope and immunohistochemistry. Light microscopically, the tumor revealed that atypical epithelial cells infiltratively proliferated in the fibrous connective tissue, part of which had mucous degeneration. The immunohistochemical study suggested that EMA was useful as an diagnosis of carcinoma in pleomorphic adenoma.

Peripheral ameloblastoma which histopathologically resembles a typical intraosseous ameloblastoma occurs in the soft tissue outside the alveolar bone. We describe a case of peripheral ameloblastoma arising in the gingiva of the premolar region in the left mandible of a 36-year-old man. A brief review of the literatures reported so far in Japan on this lesion and its differential diagnosis in relation to basal cell carcinoma are discussed.

BACKGROUND: The purpose of this study was to elucidate why odontogenic keratocysts (OKC) can form cystic lesions but not tumor masses, notwithstanding their prominent proliferative activity. METHODS: We investigated cellular proliferation, cell death, and expression of apoptosis-related proteins in the lining cells of OKCs and of dentigerous cysts (DGCs). RESULTS: TdT-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells were observed in the surface layers of OKCs and of DGCs. However, no TUNEL-positive cells were seen in the basal or intermediate layers of both cysts. Ki67-positive ratio in the intermediate layer was the highest in OKCs. The p53-positive ratio of the intermediate layer was highest in OKCs. Bcl-2-positive cells were discernible exclusively in the basal layer of OKCs. CONCLUSIONS: These results suggest that cellular proliferation and death is regulated in association with apoptosis-related proteins in the lining epithelia of OKCs, and subsequently those cysts are seen as cystic lesions but not as tumor masses. J Oral Pathol Med (2005) 34: 280–6

This case report describes an acinic cell carcinoma found by a recurrence of a ranula in the sublingual gland. A 42-year-old male was admitted to the hospital of the Tokyo Dental College with a swelling in his right oral floor but without pain. The lesion was treated by windowing the same day under the diagnosis of a ranula, but the swelling appeared again at the same area eight months after the first operation. A resection was performed, and the specimen was sent to the clinical laboratory for pathological diagnosis. Proliferating serous cells were seen in part of the wall of an exudative mucous cyst. PAS staining was partially positive, and immunohistochemical staining for S-100 protein, lactoferrin, and amylase were also positive in cytoplasmic granules. This report concludes that the pathological diagnosis is beneficial in clarifying the reasons for the recurrence of a benign lesion.

To examine the influence of cholinergic and beta-adrenergic agents on paracellular transport, we applied confocal microscopy and freeze-fracture to the isolated, perfused submandibular gland of the rat. By confocal microscopy, perfusion of lucifer yellow through an arterial catheter, revealed a bright fluorescence in the basolateral spaces of acini, but not in the intercellular canaliculi. However, addition of isoproterenol on carbachol stimulation, induced lucifer yellow fluorescence in intercellular canaliculi. This finding indicates that isoproterenol is capable of opening the paracellular route. The tight junction strands surrounding intercellular canaliculi were visualized using freeze replicas. Fixation was carried out both by vascular perfusion with Karnovsky's solution and by metal contact rapid freezing with liquid helium. In the chemically-fixed specimens, the strand particles of tight junctions formed 2-5 lines at the P-face along most of the apical portion at rest. With carbachol/isoproterenol stimulation, the strand particles rearranged with free ends and terminal loops. In the rapidly frozen specimens, the strand particles were arranged more irregularly even in the resting state. The meshwork of strands became more disheveled and interrupted during carbachol/ isoproterenol stimulation. The present findings led us to conclude that: 1) the beta-adrenergic agent, isoproterenol, can open the paracellular transport. 2) in the rapidly frozen specimen, the tight junction strand particles are arranged roughly and become disheveled and interrupted during stimulation by carbachol/isoproterenol. These findings may be related to rearrangement of subcellular structures, especially of the actin filament network.