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Urayasu, Japan

Meikai University is a private university in Urayasu, Chiba, Japan. It was founded in 1970, and obtained its present name in 1988.The university's School of Dentistry is located in Sakado, Saitama. Wikipedia.

Inoue H.,Meikai University
Journal of oral science | Year: 2011

To examine the pathogenesis of intravascular papillary endothelial hyperplasia (IPEH), a relatively uncommon benign, non-neoplastic vascular lesion, clinicopathological and immunohistochemical studies were performed. Paraffin-embedded tissue specimens of 78 vascular lesions were examined histologically, and 9 cases of IPEH were investigated immunohistochemically using antibodies against CD34, vimentin, factor VIII antigen, α-smooth muscle actin (α-SMA), podoplanin, CD105, and ki-67 antigen. A thrombus or ulcer was found near the sites of all IPEH specimens. Histologic examination revealed papillary proliferated endothelial cells located toward the lumen of enlarged blood vessels. Immunohistochemistry showed that CD34, α-SMA, and factor VIII antigen were positive in lining endothelial cells. Vimentin was positive in the mesenchymal components. Immunohistochemical staining for podoplanin and CD105 was partially positive. Labeling index was 4.7 to 9.2 in ki-67-positive cases. IPEH is believed to result from reactive proliferation of blood endothelial cells that is caused by an abnormal process of organization in thrombosed blood vessels. The pathogenesis of IPEH might be related to inflammation or mechanical stimulus such as irritation.

Human podoplanin is a type-1 transmembrane sialomucin-like glycoprotein that is involved in cell migration, tumor cell invasion and metastasis. Our recent study of oral squamous cell carcinoma (OSCC) demonstrated that the degree of immunohistochemical expression of podoplanin was correlated with the severity of epithelial dysplasia and significantly associated with a poor pathologic grade of differentiation. Furthermore, it has been reported that Src directly associates with the epidermal growth factor receptor (EGFR) in OSCC cells upon stimulation with EGF and phosphorylates Crk-associated substrate (Cas), podoplanin acting downstream of Src and Cas to promote cell migration. However, the molecular function of podoplanin remains unclear. In this study we performed real-time RT-PCR, Western blotting and scratch assay using OSCC cell lines in order to clarify the molecular biological function of podoplanin expression associated with various growth factors including EGF and with the Src-Cas signaling pathway. Podoplanin was found to have a marked influence on cancer cell migration and the expression of matrix metalloprotease-9 (MMP-9) in the oral cavity upon stimulation with EGF. Podoplanin promotes oral cancer cell migration, and the EGF-Src-Cas pathway is one of the possible mechanisms responsible for progression of cancer in the oral cavity.

Gonzalez-Alva P.,Meikai University
Journal of oral science | Year: 2011

Podoplanin, a sialomucin-like transmembrane glycoprotein, is currently used as a specific marker for lymphatic vessels. However, podoplanin expression has also been linked to tooth development. To investigate the expression of podoplanin in odontomas, 86 tissue samples were classified and then analyzed using immunohistochemical methods. Formalin-fixed, paraffin-embedded specimens were collected and classified, followed by immunohistochemical examination. The majority of the odontomas (66.3%) were the compound type, and the remainder (33.7%) were the complex type. The patients ranged in age from 2 to 89 years (mean, 23.9 years), and 45 (52.3%) of them were male and 41 (47.7%) were female. The most common location for complex odontomas was the molar region of the mandibular bone, and that for compound odontomas was the maxillary incisor region. Immunohistochemistry revealed that developing and mature odontoblasts, Tomes' fibers, and pulp cells near podoplanin-positive odontoblasts were positive for podoplanin. In addition, podoplanin positivity was evident in secretory ameloblasts, but not in mature ameloblasts. The pattern of podoplanin expression in odontomas corresponds to development of the tooth germ, and appears to be influenced by the stage of differentiation of the lesion, suggesting that the protein may participate in the process of differentiation.

Activation-induced cytidine deaminase (AID) induces cytosine deamination to generate somatic hypermutation and class switch recombnation in immunoglobulin genes. AID expression is upregulated by inflammatory cytokines such as interferon-γ and tumor necrosis factor (TNF)-α, which in turn induce p53 mutations in inflammatory or cancer cells. In this study, the effects of growth factors, cytokines or sodium butyrate on AID mRNA expression were examined in human OSCC-derived cells using real-time RT-PCR. Expression of AID mRNA was detected in OSCC cells and the expression was increased by EGF, TNF-a, or sodium butyrate. These results suggest that aberrant AID expression may play an important role in the dysplasia-carcinoma sequence in the oral cavity.

Podoplanin, a transmembrane sialomucin-like glycoprotein, is a specific marker of lymphatic vessels, and its expression is also considered to be associated with tumor invasion and tooth development. In this study, we examined the expression of podoplanin in calcifying cystic odontogenic tumor (CCOT) in comparison with that in other so-called hard α-keratin-expressing tumors such as craniopharyngioma (CP) and pilomatrixoma (PM). Immunohistochemical staining for podoplanin was carried out using surgical specimens of 15 CCOTs of the jaw, 19 CPs of the pituitary gland, and 15 PMs of the skin. Positivity for hard α-keratin was evident in ghost, shadow and transitional cells in all of these tumors (100%). The podoplanin expression in CCOTs was evident in the periphery of ameloblastoma-like epithelium (86.6%) and the epithelial cells adjacent to ghost cells (60%). On the other hand, in adamantinomatous-type CPs, podoplanin expression was observed in epithelial components corresponding to the stratum intermedium (100%), but not in the periphery of ameloblastoma-like epithelium (0%). In squamous-type CPs podoplanin was expressed in basal cells (100%), but all of the PMs were podoplanin-negative (0%). In the periphery of the ameloblastoma-like epithelium or basophilic cell layer, podoplanin was expressed more strongly in CCOTs than in CPs or PMs. These findings suggest that the expression of podoplanin in CCOTs may reflect rapid turnover of cytoskeletal filaments and local invasiveness.

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