Mouse subcutaneous tissue reaction to calcium hydroxide-based.

Mouse subcutaneous tissue reaction to an embedded calcium hydroxide-based root canal filling material was analyzed histopathologically. After the material was placed within the mouse dorsal subcutaneous tissues, we performed examinations using histopathological, histochemical and immunohistochemical techniques. Two weeks after embedment, the proliferation of granulation tissue had already begun to surround the calcification.Most of the cells observed were macrophages. Likewise, multinucleated giant cells increased significantly. The multinucleated giant cells were observed as two types. In one, the centers of the giant cells were vacuoles, while in the others there were deeply stained calcifications with hematoxylin. Twelve weeks after embedment of the materials, further growth of multinucleated giants cells were sighted. Histochemically, von Kossa-stainpositive granules were observed within the macrophages and multinucleated giant cells as black fine granules. According to the TRAP stained specimens, the multinucleated giant cells especially reacted strongly at 4 weeks. However, the reaction became very weak at 12 weeks. CD68 immunohistochemical staining showed positive reactions in the cytoplasm of the proliferating macrophages and multinucleated giant cells. These results suggest that multinucleated giant cells are present in the surrounding tissues due to implantation of the calcium hydroxidebased root canal filling material, and that the presence of ACP in the cells is due to ingested calcium during active phagocytosis, which would disappear later on

Notch signaling and ghost cell fate in the calcifying cystig odontogenic tumor

Notch signaling is an evolutionarily conserved mechanism that enables adjacent cells to adopt different fates. Ghost cells (GCs) are anucleate cells with homogeneous pale eosinophilic cytoplasm and very pale to clear central areas (previous nucleus sites). Although GCs are present in a variety of odontogenic lesions notably the calcifying cystic odontogenic tumor (GCOT), their nature and process of formation remains elusive. The aim of this study was to investigate the role of Notch signaling in the cell fate specification of GCs in CCOT. Immunohistochemical staining for four Notch receptors (Notch1, Notch2, Notch3 and Notch4) and three ligands (Jagged1, Jagged2 and Delta1) was performed on archival tissues of five CCOT cases. Level of positivity was quantified as negative (0), mild (+), moderate (2+) and strong (3+). Results revealed that GCs demonstrated overexpression for Notch1 and Jagged1 suggesting that Notch1Jagged1 signaling might serve as the main transduction mechanism in cell fate decision for GCs in CCOT. Protein localizations were largely membranous and/or cytoplasmic. Mineralized GCs also stained positive implicating that the calcification process might be associated with upregulation of these molecules. The other Notch receptors and ligands were weak to absent in GCs and tumoral epithelium. Stromal endothelium and fibroblasts were stained variably positive

Overview of Cytological Dynamics of Periodontal Ligament Inflammatory Lesions

Cyto-pathological features of the periodontal ligament tissue inflammatory lesions have somehow been carried out but detailed cellular dynamics remain unclear. Therefore, in this review, we overviewed mainly our recent experimental model studies. That is performed using using ordinary ddY mice and BMP bone marrow transplanted mouse model. Regaring the experimental apical inflammatory periodontitis, at four weeks, micro-CT confirmed the presence of a radiolucent image at the apex of the tooth, which was then removed for histological examination. The results showed granulation tissue with fibrosis gradually formed at the periphery of an abscess. Next, if perforation were large, granulation tissue would grow to form periodontal polyp. Results of micro-CT revealed alveolar bone resorption and widening of periodontal ligament. Histopathological examination showed proliferation of fibroblasts with some round cells and blood vessels in the granulation tissue. Double immunofluorescent staining of GFP and Runx2 revealed that both proteins were expressed in spindle-shaped cells. Double immunofluorescent staining of GFP and CD31 revealed that both proteins were expressed in vascular endothelial cells in morphologically distinct vessels. The results suggest that fibroblasts, periodontal ligament fibroblasts and blood vessels in granulation tissue were derived from transplanted-bone marrow cells. Thus, essential growth of granulation tissue in periodontal polyp was caused by the migration of undifferentiated mesenchymal cells derived from bone marrow, which differentiated into fibroblasts and later on differentiated into other cells in response to injury

Differential expression of canonical and non-canonical Wnt ligands in ameloblastoma

BACKGROUND: Canonical and non-canonical Wnt signaling pathways modulate diverse cellular processes during embryogenesis and post-natally. Their deregulations have been implicated in cancer development and progression. Wnt signaling is essential for odontogenesis. The ameloblastoma is an odontogenic epithelial neoplasm of enamel organ origin. Altered expressions of Wnts-1, -2, -5a, and -10a are detected in this tumor. The activity of other Wnt members remains unclarified. MATERIALS AND METHODS: Canonical (Wnts-1, -2, -3, -8a, -8b, -10a, and -10b), non-canonical (Wnts-4, -5a, -5b, -6, 7a, -7b, and -11), and indeterminate groups (Wnts-2b and -9b) were examined immunohistochemically in 72 cases of ameloblastoma (19 unicystic UA, 35 solid/multicystic SMA, eight desmoplastic DA, and 10 recurrent RA). RESULTS: Canonical Wnt proteins (except Wnt-10b) were heterogeneously expressed in ameloblastoma. Their distribution patterns were distinctive with some overlap. Protein localization was mainly membranous and/or cytoplasmic. Overexpression of Wnt-1 in most subsets (UA = 19/19; SMA = 35/35; DA = 5/8; RA = 7/10) (P < 0.05), Wnt-3 in granular cell variant (n = 3/ 3), and Wnt-8b in DA (n = 8/ 8) was key observations. Wnts-8a and -10a demonstrated enhanced expression in tumoral buddings and acanthomatous areas. Noncanonical and indeterminate Wnts were absent except for limited Wnt-7b immunoreactivity in UA (n = 1/ 19) and SMA (n = 1/ 35). Stromal components expressed variable Wnt positivity. CONCLUSION: Differential expression of Wnt ligands in different ameloblastoma subtypes suggests that the canonical and non-canonical Wnt pathways are selectively activated or repressed depending on the tumor cell differentiation status. Canonical Wnt pathway is most likely the main transduction pathway while Wnt-1 might be the key signaling molecule involved in ameloblastoma tumorigenesis. J Oral Pathol Med (2012) 41: 332-33

Localization of oxytalan fiber, type III collagen and BMP family in conventional and desmoplastic ameloblastoma

The histologic hallmark distinguishing desmoplastic ameloblastoma (DA) from conventional ameloblastoma (CA) is its pronounced stromal desmoplasia, and this formed the basis of this investigation. To elucidate the stromal characteristics, localization patterns of oxytalan fibers, type III collagen and BMP family in DA (n=8) was compared with CA (n=24), and periodontal ligament (PL) (n=8). Oxytalan fibers formed apico-occlusal bundles in PL, thick radial bundles around tumor nests in DA, and as scanty fibers in CA. Type III collagen was identified in PL, strongly expressed in DA stroma, but weakly in CA. BMP-2, -3, -4 and -7 expression patterns in tumor epithelium and stroma were more pronounced in DA (including sites of bone formation), than CA. No immunoreactivity for BMP-5 and -6 were detected. Current findings suggest that the stroma in DA is neoplastic and derived from odontogenic ectomesenchyme, and recommends its reclassification as an odontogenic epithelial-ectomesenchymal neoplasm

The engraftment and differentiation of transplanted bone marrow-derived cells in the olfactory bulb after methimazole administration

Conclusion: Bone marrow-derived cells can be engrafted in the olfactory bulb and a few cells can differentiate into mitral/tufted cells in the olfactory bulb. Objectives: To investigate whether bone marrow-derived cells can be engrafted into the olfactory bulb and differentiate into neurons and glial cells after methimazole administration. Methods: Bone marrow of GFP (green fluorescence protein) mice was transplanted into lethally irradiated recipient mice. Immunostaining was performed to confirm the cell types of bone marrow-derived cells expressing GFP. Results: GFP-positive cells were observed in the olfactory bulb at 2 days after methimazole administration. The number of dendritic GFP-positive cells increased up to 30 days after methimazole administration and then decreased. Double immunostaining for GFP and Iba1 or TBX21 showed that a large population of the GFP-positive cells had characteristics of microglia/macrophages and a few cells had characteristics of mitral/tufted cells

A pigmented calcifying cystic odontogenic tumor associated with compound odontoma: a case report and review of literature

<p>Abstract</p> <p>Background</p> <p>Pigmented intraosseous odontogenic lesions are rare with only 47 reported cases in the English literature. Among them, pigmented calcifying cystic odontogenic tumor, formerly known as calcifying odontogenic cyst, is the most common lesion with 20 reported cases.</p> <p>Methods</p> <p>A case of pigmented calcifying cystic odontogenic tumor associated with odontoma occurring at the mandibular canine-premolar region of a young Japanese boy is presented with radiographic, and histological findings. Special staining, electron microscopic study and immunohistochemical staining were also done to characterize the pigmentation.</p> <p>Results</p> <p>The pigments in the lesion were confirmed to be melanin by Masson-Fontana staining and by transmission electron microscopy. The presence of dendritic melanocytes within the lesion was also demonstrated by S-100 immunostaining.</p> <p>Conclusion</p> <p>The present case report of pigmented calcifying cystic odontogenic tumor associated with odontoma features a comprehensive study on melanin and melanocytes, including histochemical, immunohistochemical and transmission electron microscopic findings.</p

NOTCH SIGNALING IN BENIGN AND MALIGNANT AMELOBLASTIC NEOPLASMS

Background: In general, Notch is a representative signal which controls morphosis and differentiation of cells, but its role in human odontogenic neoplasms, especially in ameloblastoma and its malignant counter-part, ameloblastic carcinoma, is not known. Methods: We examined Notch1 peptide and its gene (mRNA) in an ameloblastoma (case 1: 27-year-old female, right mandibular tumor) and an ameloblastic carcinoma (case 2: 93-year-old female, right mandibular tumor), using immunohistochemistry (IHC) and in situ hybridization (ISH) techniques. Results: Notch1 intracellular domain (NICD) Positive products were observed in the cells at the peripheral layer of most proliferating epithelial tumor nests in case 1. In case 2, positive products were similarly detected. In particular, small numbers of mitoses were identified in the nuclear region With intense NICE positive reaction. Conclusions: Notch signaling plays some role in cytological differentiation or acquisition of tissue specific characteristics in neoplastic cells of odontogenic neoplasms including ameloblastoma and ameloblastic carcinoma. Notch I may also contribute to Cell cycle arrest induced by Notch1 activation in ameloblastic carcinoma. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down

Strawberry gingivitis as the first presenting sign of wegener's granulomatosis: report of a case

Abstract Wegener's granulomatosis is a rare multi-system disease characterized by the classic triad of necrotizing granulomas affecting the upper and lower respiratory tracts, disseminated vasculitis and glomerulonephritis. Oral lesions as a presenting feature are only encountered in 2% of these cases. Hyperplastic gingival lesions or strawberry gingivitis, is a characteristic sign of Wegener's granulomatosis. The latter consists of reddish-purple exophytic gingival swellings with petechial haemorrhages thus resembling strawberries. Recognition of this feature is of utmost importance for timely diagnosis and definitive management of this potentially fatal disease. A case of strawberry gingivitis as the first presenting sign of Wegener's granulomatosis affecting a 50-year-old Malay male is reported here. The differential diagnosis of red lesions that may present in the gingiva is discussed.</p