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Notes: The correlation between clinical periodontal parameters and histological structure of the gingiva around a single-crystal sapphire implant has been evaluated in two volunteer subjects. The implants had functioned after 6 years as the distal abutment of implant bridges in the Kennedy class II mandible. First, clinical evaluation was performed (gingival bleeding index, crevicular fluid volume, plaque index and probing depth) of the gingiva around the implant and natural teeth abutments and then a small piece of peri-implant gingiva was excised from the lingual site of the implant of each subject for histological evaluation. The clinical evaluation using the periodontal parameter indices corresponded with the histological evaluation of the peri-implant gingiva. The result suggests that it is possible for such parameters to be used in practice for judging the success of an implant.

Notes: Cibacron blue 3G-A (CB), one of the triazinyl dyes commonly used as a ligand for affinity chromotography, induced staphylococci to form giant clusters without affecting cell variability. It was demonstrated that the cluster formation was not a mechanical aggregation of cells by CB, but a consequence of its biological effect on staphylococcal growth. Clusters induced by CB did not form a regular arrangement, and were different from clusters induced by SDS or polyanethole sulfonate.

Notes: Abstract: To evaluate the biological effects of guided bone regeneration (GBR) barrier materials on osteoblastic cell migration, migration of mouse osteoprogenitor cells (MC3T3-E1) was examined, in vitro, on various membranes. Eight commercially available GBR membranes – bovine type I collagen (BioMend®; BM), porcine type I collagen (BioGide®; BG), bovine type I atelocollagen (Tissue Guide®; TG), polylactic acid (Epi-Guide®; EG), co-polymer of polylactic acid and polyglycolic acid (Resolute®; RL, Resolut XT®; RL-XT), expanded polytetrafluoroethylene (e-PTFE; Gore Tex®; GT) and co-polymer of cellulose acetate and nitrocellulose (Millipore filter®; MP) – were tested. A 3×5 mm section of the membrane was fixed to the bottom of a culture dish with double-sided adhesive tape, and half of the membrane was closely covered by PARAFILM® (American National CanTM) to leave an unexposed area for cell migration. The border between exposed and unexposed areas was marked as a baseline of cell migration. Membranes were then plated with 3 ml of cell suspension at an initial density of 1×105 cells/ml in α-MEM culture medium with 10% fetal bovine serum and ascorbic acid. After a 5-hour incubation, non-attached cells were completely washed out with phosphate buffered saline and the PARAFILM® cover was removed. After 3 days cultivation, specimens were fixed with 10% buffered formalin and stained briefly with hematoxylin. The area of cell migration on a membrane was analyzed using a LA 500 Image Analysis System and migration area per unit length of the baseline (mm2/mm) was compared among membranes. Results demonstrated that cell migration was greater in the order: RL〉RL-XT, BM, TG, MP〉EG, BG. Membranes except for BG, EG and GT showed the migration rate equal to or higher than a plastic culture cover slip (Celldesk®) (P〈0.01) on which cells generally grow favorably. Only a small number of the cells attached to GT, and the net cell migration for the membrane could not be determined. These results indicate that GBR barrier materials per se may influence the process of bone regeneration in vivo through the effects of their presence on cell migration.

Notes: The clinico-pathologic, immunohistochemical and radiological features of 12 jaw cysts with a prominent orthokeratinized epithelial lining were studied and compared with those of typical odontogenic keratocysts and dentigerous cysts. They differed significantly from odontogenic keratocysts in terms of biologic behavior and histopathologic findings. Although immunohistochemical staining of the epithelial linings for cytokeratins. EMA, CEA and involucrin has not shed any light on the histogenesis of these lesions, staining patterns for these markers were significantly different from those of odontogenic keratocysts and non-keratinized dentigerous cysts. Radiologically, nine cases appeared as dentigerous cysts; two cases, one with sebaceous differentiation, as non-dentigerous unilocular cysts, and the remaining one was exceptional as it showed multiple epidermal cysts with prominent dermal appendages histologically. It is suggested that most of the orthokeratinized jaw cysts may belong to ctinko-pathological entities different from odontogenic keralocysts with the majority representing dentigerous cysts with orthokeratinization. The possibility of the existence of rare central dermoid or epidermoid cysts is also to be considered.

Notes: A case of clear cell odontogenic tumour, which occurred centrally in the mandible of a 56-year-old Japanese woman, is reported with its histochemical, immunohistochemical and ultrastructural findings. Histologically, the tumour nests were composed of large glycogen-rich clear cells and small non-clear polygonal cells and were separated by thin mature fibrous connective tissue septae. Immunohistochemically, both types of tumour cells showed positive expression of various cytokeratins, in particular cytokeratin 19, and of epithelial membrane antigen. Eosinophilic hyaline deposits and possible dentin-like structures were occasionally formed in contact with the epithelial nests and are regarded as indicative of the epithelial-mesenchymal inductive capacity of this tumour. The aggressive nature of the present tumour was assumed through its invasive growth pattern and occasional mitotic figures. Although it was diagnosed as clear cell odontogenic tumour according to the present WHO classification, the patient must be followed carefully because of its probable malignant nature.

Notes: Only 12 odontogenic ghost cell carcinomas (OGCC) have been reported in the English language literature to date. This article reports four additional cases of this rare odontogenic tumour and examines them in relation to those previously described. Judging from the number of published cases, the OGCC is more prevalent in Asians than other racial groups, occurs more often in the maxilla than the mandible, and is slightly more common in males than females. Histologically, elements of a benign calcifying odontogenic cyst (COC) can be identified in all the malignant variants, either separated or admixed with the malignant epithelial component. The latter can consist of either small basaloid cells or large epithelial cells. Despite the differing histological presentations, the biological behavior of the tumour is unpredictable, with some cases characterized by relatively indolent growth and others by a locally aggressive and potentially fatal course. The tumour apparently arises most often from malignant transformation of a preexisting benign COC, although it may also develop from other odontogenic tumours.

Notes: To investigate the effect of lipopolysaccharide (LPS) on phagocytic activity of collagen fibrils by periodontal fibroblasts, we studied rat molar gingival connective tissue and periodontal ligament under light and electron microscopy after topical application of LPS (5 mg/ml in physiological salt solution (PS)) on the gingival sulcus. Phagocytic activity of collagen fibrils by fibroblasts was evaluated by counting the number of collagen-containing vacuoles inside fibroblasts that were present within a defined area (1200 μm2). Values obtained from fibroblasts in the subepithelial connective tissue, the region near the alveolar crest, and the middle region of periodontal tissue were compared. Periodontal ligament fibroblasts showed increased phagocytosis of the collagen fibrils from 3 hours to 1 day after topical LPS application, but no differences were observed in the gingival tissue. The intracytoplasmic vacuoles containing collagen fibrils were of various sizes and shapes, showing positive for acid phosphatase and/or alkaline phosphatase reaction. Collagen phagocytic activity of the fibroblasts in the middle region of the periodontal ligament also increased after PS treatment. However, this was significantly less than that observed in LPS-treated animals (p〈0.01). This study indicates that LPS may enhance the degradation of collagen by stimulating the phagocytic activity of the periodontal ligament fibroblasts.

Notes: Structures taking part in the lysosomal system of rat junctional epithelium (JE) were evaluated by means of ultrastructural enzyme cytochemistry. Acid phosphatase (AcPase) and trimetaphosphatase (TMPase), both the representative lysosomal marker enzymes, were frequently detected in dense bodies which contained the homogeneous matrix and showed pleomorphic appearance. These activities were also often localized to the phagosomes with heterogeneous contents, the reaction of TMPase being much more intense than that of AcPase. Cisternal structures, most probably corresponding to GERL, also displayed AcPase activity and exhibited the close morphologic relationships with lysosomal structures. On the other hand, the localization of thiamine pyrophosphatase activity was almost limited to the innermost cisterna of the Golgi complex. Neither AcPase nor TMPase activity could be detected in the cytoplasmic vacuoles, which were characteristically numerous in rat JE and the multivesicular bodies.From the present findings, it is suggested that the lysosomal system in rat JE is composed of dense bodies (primary lysosomes), phagolysosomes (secondary lysosomes), and GERL and that some of those lysosomes are apparently derived from GERL. Different localization patterns of marker enzymes examined might reflect the enzymatic heterogeneity of various lysosomal elements.

Notes: To discuss the role of macrophage lineage cells on the periodontal tissue destruction, we immunohistochemically examined the phenotype and the dynamics of macrophage lineage cells 1 or 3 h or 1, 2, 3 or 7 d after topical application of LPS (5 mg/ml in physiological saline) from the rat gingival sulcus using 3 monoclonal antibodies: OX6 (antigen-presenting cells), ED1 (monocytes, macrophages and dendritic cells) and ED2 (resident macrophages). We could detect at least 3 different types of macrophage lineage cells, namely OX6+/ED1+/ED2− dendritic cells and exudate macrophages and ED2+ resident macrophages. After LPS application the majority of macrophage lineage cells accumulated in the subjunctional epithelial area were newly extravasated OX6+/ED1+/ED2− dendritic cells or macrophages. The number Department of Oral Pathology, Hiroshima of these cells increased progressively with time and reached a maximum level at University School of Dentistry, d 2. On the other hand, number and tissue distribution of ED2+ resident macrophages did not change. These results indicate that several types of macrophage lineage cells exist in rat gingival tissue and suggest that dendritic cells and exudate macrophages transiently accumulated after LPS application are responsible for various host immune response and tissue destruction caused by LPS.

Notes: True malignant mixed tumor (TMMT) of salivary glands, with both carcinoma-tous and sarcomatous components, is exceedingly rare. We offer a case of TMMT in a 79-yr-old man, which may represent the first reported example of this unusual neoplasm arising in the tongue. The carcinomatous component was mainly of solid basaloid carcinoma with focal glandular differentiation, while the sarcomatous component was composed of pleomorphic elements such as chondrosarcoma, myxosarcoma and fibrosarcoma. Carcinoma cells at the periphery of solid nests occasionally merged into these sarcomatous elements. Immunohis-tochemically, basaloid carcinoma cells showed positive reaction for both low molecular weight cytokeratin and S-100 protein, whereas carcinoma cells lining ductal spaces were positive for a wide spectrum of keratin and EMA. The sarcomatous elements revealed the presence of vimentin and S-100 protein. Ultra-structurally, basal lamina-like material and/or mucoid precipitates often accumulated separating the tumor cells from each other singly or into a few cell group. Some sarcomatous cells assumed the myoepithelial features, such as the presence of microfilament bundles with dense bodies and pinocytotic vesicles along the cell periphery. These findings may indicate that TMMT shares a common histogenesis with pleomorphic adenoma.