With the aim of clarifying cell dynamics during osseous healing of extraction sockets, 44 groups were prepared, and ³H-Thymidine (RI) was administered to mice at 1, 2, 3, 4, 5, 6, 7 and 10 days after tooth extraction. The animals were basically sacrificed for autoradiography day by day in chronological order of administration.
The cell labeling index (LI) and histological findings were compared between each experimental group. When the RI was given during the blood-clot or gran-ulation-tissue period, the LI sustained a high level that persisted through the terminal healing stage. During the ossification period, numerous intensely labeled osteocytes were found within the floor and around the socket wall when the RI was administered during the bloodclot period, and at the middle portion of the socket when the RI was given during the granulation-tissue period.Intensely labeled osteocytes were found at the rim of the socket when the RI was given not only during the bloodclot and granulation-tissue periods, but also during the early ossification period. The total number of cells began to decrease during the fourth post-extraction day, accompanied by the appearance of apoptotic cells.
These results suggest that healing of extraction sockets proceeds from the floor and the area around the wall to the middle part of the socket and, finally, to the rim. In addition, undifferentiated mesenchymal cells and fibroblasts that proliferate in the early post-extraction period continue to divide, but decrease in number seemingly due to apoptosis. Further, a large proportion of these cells differentiate into osteocytes.

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In previous clinical immunohistochemical studies, the authors found that parathyroid hormone-related protein (PTHrP) was expressed in oral squamous cell carci nomain which the localization corresponded to regions of higher keratinization and lower grade of histologic malignancy. This study examined the effect of PTHrP on proliferation and differentiation of oral squamous cells. We used a squamous carcinoma cell line, SCC-25, derived from tongue cancer, and an immortalized keratinocyte cell line, NDUSD-1, derived from human gingival tissue. PTHrP (1-34), (34-53) and (107-139) fragments were added to the culture medium. For assessment of prolif eration, we counted the number of cells. The ability of the fragments to affect differentiation was evaluated by using immunofluorescent staining with involucrin, cyto keratin (CK) 10, CK14, CK5, CK6, and CK18. We also assessed intracellular cAMP concentration. No changes in cell number or immunofluorescence staining were evident in either cell line following stimulation with the fragments. The concentration of cAMP did not change in either cell line after adding the fragments. PTHrP fragment (1-34) did not increase CK expressions in NDUSD-1 in a cDNA microarray study. Although it has been reported that PTHrP affects differentiation of keratinocytes in an antisense RNA study, we did not observe any influence of exogenously added PTHrP on cell differentiation and proliferation in the examined cell lines. The endogenous function of the fragments in oral sauamous cells requires further study.

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Angiogenesis plays a critical role in the growth and metastasis of solid tumors. Vascular endothelial growth factor (VEGF) is one of the most potent angiogenic fac torsproduced by tumor cells, and its synthesis has been shown to be modulated through the activation of some transcription factors including HIF-1 induced by hypoxic condition. We transfected synthetic oligodeoxynucleo tides (ODNs) with consensus sequence for HIF-1 bind ing (HIF-1 decoy ODNs) into cultured cancer cells (SAS cells) using the hemagglutinating virus of Japan (HVJ)-liposome method. The hypoxia induced overexpression of VEGF in SAS cells could be apparently suppressed by the transfection of HIF-1 decoy ODNs. These results suggest that the HIF-1 decoy strategy would be effective for regulating tumor growth by reducing angiogenic ac tivityof cancer cells through HIF-1-mediated gene trans activations.

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In mandibular condylar fracture where open reduction is difficult to perform, a decrease in mandibular ramus height may occasionally lead to malocclusion or temporomandibular joint dysfunction. Here, we report two cases with a high condylar fracture in whom favorable results were obtained by performing distraction osteogenesis to address a decrease in the mandibular ramus height.

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Mucoepidermoid carcinoma is the most common malignant salivary gland neoplasm. In previous reports, about 50% of this tumor occurred in the parotid gland and about 20% in the palatine gland. Mucoepidermoid carcinoma in lingual gland, especially the anterior lingual gland, is very rare.
The present case is mucoepidermoid carcinoma arising in the proglossis. A 31-year-old female visited our hospital complaining of abrupt swelling in the anterior surface of the tongue. An incisional biopsy was performed, followed by a partial glossectomy.
After 5 years, late metastases were found in the cervical lymph nodes and radical neck dissection was performed. There is no recurrence or distant metastasis at present.

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We report two cases of hemodialysis-associated amyloidosis occurring in the oral region. Case 1: A 71-yearold male was referred to our hospital because of mass formation and spontaneous pain of the tongue and buccal mucosa on May 28, 2003. Intraoral examination revealed that there were firm and waxy white-yellow nodular lesions of the tongue and buccal mucosa. He had been given a diagnosis of chronic renal failure in 1974 and had received hemodialysis treatment for 29 years. Thus, we clinically suspected hemodialysis-associated amyloidosis. To diagnose these nodular lesions, we surgically resected one of the lesions of the buccal mucosa. Histopathologically, the lesion was diagnosed as hemodialysis-associated amyloidosis involving tongue and buccal mucosa. Case 2: The patient was a 54-year-old male who had been undergoing hemodialysis treatment for 29 years. He had noticed a mass lesion on the inferior surface of the tongue, and visited our department on January 8, 2003. Intraoral examination revealed a white-yellow tumorous lesion located on the underside of the tongue. We clinically diagnosed benign tumor of the tongue. The mass was surgically resected under general anesthesia. Histopathological examination revealed that the mass was amyloid deposit.

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