The immunopathology of most autoimmune diseases has been well defined, but the mechanisms responsible for the breakdown of self-tolerance and which lead to the development of autoimmune lesions are still unclear. Primary SjÖgren's syndrome in humans is known to be an autoimmune disease characterized by diffuse lymphoid cell infiltration in the exocrine organs, involving in particular the salivary and lacrimal glands. The pathogenesis of this syndrome remains unclear, but the majority of infiltrating cells in the salivary glands were CD4⁺ T cells both in humans and rodents. Since many cytokines and adhesion molecules are involved in the development of T cell-mediated autoimmunity, we have investigated local cytokine, and adhesion molecule gene expression using animal model for primary SjÖgren's syndrome in MRL/lpr, and NFS/sld mice. Overexpression of interleukin-l(IL-1) β and tumor necrosis factor(TNF)-α, interferon(IFN)-γ, IL-6, IL-10, IL-12(p40) was detected in the salivary gland, and the up-regulation of ICAM-1, LFA-1, CD44, Mel-14 mRNA was found in accordance with autoimmune sialadenitis. In addition, we have analysed the expressionn of T cell antigen receptor(TCR)V β transcripts in the salivary gland tissues. Transcript for V β 8 was predominantly detected in the T cell infiltrating sialadenitis from the onset of the disease, suggesting that CD4+ T cells bearing TCR V β 8 are play essential roles to recognize unknown autopeptide in the autoimmune salivary gland disease.

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We characterized the two human osteosarcoma cell lines from an osteoblastic parosteal osteosarcoma arising in the right tibia and from a metastatic lesion of a 27-year-old female patient, designated as KIKU and KIKU-M cells, respectively. An investigation of the nature of human osteosarcoma cell lines derived from primary and secondary lesions of the same patient has not been previously reported. These cell lines had different growth rates, morphologies, chrosomomal analyses, ALP activities, amounts of BGP, and invasive capacities. Prominent osteoid formation and calcification were observed in osteosarcoma tissues produced by the subcutaneous transplantation of both cell lines. These results suggested that KIKU-M cells had more immature phenotypic features than did KIKU cells in vitro and in vivo. In addition, both cell lines provide useful models for studying metabolism of human osteoblasts in vitro and the mechanisms of the differentiation and metastasis of human osteosarcoma.

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Experimental periodontitis was induced in the premolars of two adult beagle dogs by cotton ligature placement and administration of a soft diet that facilitated plaque accumulation over 24 weeks. Periodontal flap surgery, including root planing was carried out by using curettes and root demineralization with 0.3 N hydrochloric acid (HA) for 5 min. In the HA-demineralized group, new cementum formation was seen on the non-resorbed dentin surfaces, and the newly formed cementum matrix fibers became interlaced and/or attached to the exposed dentin matrix fibers through an amorphous granular substance. In the non-HA-demineralized control group, the regenerated junctional epithelium covered the planed dentin surface, and no new cementum formation was observed. The present study suggests that 0.3N HA treatment can induce the formation of new connective tissue attachment to a previously diseased root surface.

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The effects of MeIQx and EGF applications on the tongues of hamsters after excisional wounding were investigated histologically. The tongues of the control animals which received applications of distilled water after excisional wounding showed only a hyperkera-tinized epithelium. In contrast, the tongues of the animals which received applications of MeIQx after excisional wounding exhibited epithelial dysplasia. The tongues of the animals which received applications of EGF after excisional wounding displayed a hyperparakera-tinized epithelium without epithelial dysplasia. The tongues of the animals which received applications of both MeIQx and EGF together after excisional wounding showed a hyperkera-tinized epithelium similar to those of the controls.

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Primary malignant melanoma in situ of the lower lip is exceedingly rare. Two Japanese patients with malignant melanoma in situ in the mucous membrane of the lower lip are presented. One case was an 31-year-old female, and the other was an 14-year-old boy. Micro-scopically, atypical melanocytes evidenced by prominence of nuclei and nucleoli were observed, which were distributed individually as well as occasionally in nests. Atypical mitosis were frequently found in both cases. Ultrastructural examination recovered from paraffin sections confirmed the presence of melanozomes in these atypical melanocytes. Immunohistochemically, positive reactivity with ras P21 monoclonal antibody was observed in these atypical melanocytes. These findings indicated that malignant melanoma in situ may occur in the mucous membrane of the lower lip in rather younger generation.

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An autopsy case of epithelioid angiosarcoma of the maxilla of a 69-year-old Japanese man is presented. Microscopic examination of a biopsy specimen of the primary maxillary tumor revealed the solid and sheet-like proliferation of atypical, large, polygonal tumor cells with large, irregular nuclei and prominent nucleoli. Immunohistochemically, the tumor cells were strongly positive for cytokeratin. Metastases were detected in the stomach, the cerebrum, and the 12th thoracic vertebra. The patient died in cachexia 9 months after the partial maxillectomy. In the autopsy specimens, metastatic tumor cells proliferated in a sheet-like fashion and formed irregularly shaped vascular channels. Immunohistochemically, tumor cells showed activity for cytokeratin, FVIII-RA, CD31, and vimentin.

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Adenocarcinoma is a relatively rare neoplasm in the submandibular gland. When poorly differentiated, it is difficult to diagnose differentially from other carcinomas, including carcinoma in pleomorphic adenoma, adenosquamous carcinoma, and undifferentiated carcinoma in the salivary gland. To differentiate a salivary gland tumor arising from the left submandibular gland of a 83-year-old-male patient, we performed an immunohistochemical examination using total keratin(TK), S-100 protein, secretory component (SC), actin, epithelial membrane antigen (EMA), lactoferrin, vimentin, glial fibrillary acidic protein (GFAP), and amylase. The tumor reacted positively to TK, S-100 protein, SC, actin, EMA, vimentin and lactoferrin. We reviewed the Japanese literature on 15 cases of adenocarcinoma and 5 cases of carcinoma in pleomorphic adenoma arising from the major salivary glands and discussed the relationships between immunohistochemical features and histogenesis.

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The light microscopic, electron microscopic and immunohistochemical features of a large cell undifferentiated parotid gland carcinoma are presented. The tumor was composed predominantly of undifferentiated, polygonal large cells with focally admixed malignant oncocytic cells. The presence of carcinoembryonic antigen, lactoferrin, lysozyme and secretory component in the oncocytic tumor cells was found immunohistochemically, whearas no immunoreactivity with the tested biological markers was observed in undifferentiated polygonal large cells. Ultrastructurally, numerous mitochondria with crescent-shaped cristae were packed in the tumor cells within the oncocytic cell areas, and junctional complexes between the neighboring cells represented contiguous tight junctions and distinct desmosomes in the area of undifferentiated cells.

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The fungus ball of aspergillosis in the maxillary sinus -with calcification and brown pigmentation was investigated by means of histopathologically, histochemically and electron probe microanalytically. The central area of the mass was composed of necrotized tissues containing brown pigments and calcified granules while in the peripheral region septate fungal hyphae and conidial heads resembling Aspergillus nigar were observed. The calcified granules were manifested as calcium oxalate histopathologically and did not contain phosphorous but calcium suggesting also calcium oxalate electron probe microanalytically.

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The characteristics of four cases of dilated odontoma were studied using thinly sliced decalcified sections and non-decalcified ground sections. Histological features common to the lesions in all four cases included an outer layer of cementum which enclosed a layer of dentin. Enamel was found within the dentin layer. The proliferation of irregular,calcified tissue with no distinct tissue structure was seen at the center of the lesion.This tissue was apparently derived primarily from dentin and partially from enamel. Dilated odontoma is considered to be a lesion positioned between dens invaginatus and complex odontoma.

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The authors report a rare case of a mandibular dentigerous cyst involving two impacted molars in a 48-year-old Japanese man. Two crowns of the third molar and the fourth supernumerary one were facing each other in the cystic lumen. Histologically, the cyst wall was composed of fibrous granulation tissue with a squamous-epithelial lining. The pathogenesis is discussed, based on a review of the literature of dentigerous cysts and supernumerary teeth.

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