Biomedical subjects

Shuichi Fujita

Publications and source records attributed to Shuichi Fujita.

6 recordsLinked to original sources

PubMed2006

The prevalence of human papillomavirus genotypes in penile cancers from northern Thailand.

The highest frequency of penile cancer occurs in Asia, Africa, and Latin America, and there have been a few reports concerning the association of penile cancer with human papillomavirus (HPV) infection in these areas. The objective of this study was to determine the relation between penile cancer and the prevalence of HPV genotypes in northern Thailand. Eighty-eight specimens of penile tissue (65 malignant, 1 pre-malignant, and 22 benign cases) were examined to determine the association of HPV infection. An in situ hybridization (ISH) method was used to detect and localize HPV-DNA. Sensitive HPV polymerase chain reaction (PCR) procedure was used for detection of HPV-DNA, and DNA sequencing was used to identify the HPV genotype. HPV-DNA was detected in 53.8% and 81.5% of cases of penile cancer, using ISH and PCR, respectively. The high-risk HPV-16, most commonly associated with penile cancer in previous reports, was found in only one case in this study. The most prevalent genotype was the high-risk HPV-18, found in 55.4% of the cases (32.3% single and 23.1% multiple infection) followed by the low-risk HPV-6, found in 43.1% of the cases (24.6% single and 18.5% multiple infection). In this study, penile cancer was found to be highly correlated with HPV-DNA. Specifically, infection with both the low-risk HPV-6 and the high-risk HPV-18 is the characteristic prevalence of HPV genotypes in penile cancer in this area.

Adult↗

PubMed2005

A case of mucoepidermoid carcinoma with melanin pigmentation manifested in the palate.

This paper describes the first documented case of mucoepidermoid carcinoma (MEC) with melanin pigmentation manifested in the palate. Histopathological sections showed a neoplasm composed of epidermoid, mucous-producing and intermediate cells. Numerous large cells contained dark pigmented materials. Fontana Masson staining revealed dendritic melanocytes and melanin granules. HMB-45, Melan A and S-100 protein were all positive for melanocytes. Histopathological examination was not typical for malignant melanoma; the lesion was diagnosed as a low-grade MEC with melanin pigmentation.

Adult↗

PubMed2005

Ameloblastoma.

Explore the source record for details and available documents.

Aged↗

PubMed2004

Early stage of Epstein-Barr virus lytic infection leading to the "starry sky" pattern formation in endemic Burkitt lymphoma.

CONTEXT: Burkitt lymphoma (BL) is histologically characterized by a "starry sky" appearance, representing scattered macrophages that have phagocytosed cell debris among proliferating lymphoma cells. As is well known, almost all the neoplastic cells of endemic BL are infected with Epstein-Barr virus (EBV). Previous studies have indicated that most of the EBV in B cells is latent, and few virus particles enter the lytic cycle. OBJECTIVE: To examine the histologic relationship between EBV infection stages and the formation of the starry sky pattern in African endemic BL tissues. DESIGN: Tissue samples from 44 patients with African endemic BL were examined with immunohistochemistry and in situ hybridization. We used EBV-encoded small RNA (EBER) as a marker of latent infection, and BamHI H left frame 1 (BHLF1) and BamHI Z EBV replication activator (ZEBRA) as lytic cycle markers. RESULTS: In all cases, signals for EBER were found in most neoplastic lymphocytes, and in 73% of cases, signals for BHLF1 and/or ZEBRA were recognized in the lymphoma cells within and around the lacunae in starry sky figures. The mean number of lacunae per unit area in cases positive for lytic cycle markers was significantly higher than that in negative cases (P <.001). CONCLUSIONS: Our findings suggest that EBV-infected lymphoma cells in the lytic cycle, which eventually lapse into cell death, are phagocytosed prior to their rupture by macrophages that have migrated into the parenchyma. We emphasize that transition of EBV-infected lymphoma cells to the lytic cycle is one of the histomorphogenetic factors influencing the formation of starry sky pattern in endemic BL.

Adolescent↗

PubMed2002

Mucoepidermoid carcinoma arising in Warthin's tumor of the parotid gland.

Malignant transformation of Warthin's tumor is extremely rare, although it is the second most common benign tumor of the parotid gland. We describe our experience of mucoepidermoid carcinoma arising in Warthin's tumor of the parotid gland in a 64-year-old man. He had a swelling in the left parotid-masseteric region. The removed tumor was well encapsulated and histopathologically comprised Warthin's tumor and low-grade mucoepidermoid carcinoma. The mucoepidermoid carcinoma infiltrated lymphoid stroma of the Warthin's tumor, but capsular invasion is not found. Considering the clinical course and physical examination, the lesion was diagnosed as mucoepidermoid carcinoma arising in Warthin's tumor because its features filled the criteria of malignant transformation of Warthin's tumor. There has been no recurrence or distant metastasis for 19 months. Histological change from Warthin's tumor to mucoepidermoid carcinoma may be implicated in squamous or goblet cell metaplasia of epithelial cells. It is considered that the neoplastic cells of Warthin's tumor acquire malignant genotypes simultaneously with this dual differentiation.

Adenolymphoma↗

PubMed2002

Involvement of Fas/Fas ligand in the induction of apoptosis in chronic sialadenitis of minor salivary glands including Sjögren's syndrome.

The role of apoptosis and contribution of Fas/FasL systems in the pathogenesis of Sjogren's syndrome (SS) are still controversial. With serial sections, we explored apoptosis assessed by the dUTP nick end labeling (TUNEL) method and expression of Fas and FasL by immunohistochemistry, and compared their distribution in minor salivary gland (MSG) of SS and sialolithiasis (SIL) patient tissues. Fas and FasL were co-localized in ductular and acinar cells of SS and SIL TUNEL+ cells co-distributed with the Fas and FasL expressing cells in ductular and acinar cells of SS in the vicinity of lymphocytic infiltration, while not in those of SIL Moreover, to morphologically confirm apoptosis, we identified TUNEL-positive(+) cells in the MSGs of SS at the ultra structural level by applying an inversion method to paraffin-embedded sections stained by TUNEL method. Surprisingly, these cells did not show characteristic apoptotic figures although TUNEL products were deposited on the hyperchromatin of acinar and ductular cells. On the other hand, acinar and ductular cells of SIL included clusters of TUNEL+ apoptotic bodies as did those cells by phagocytosis or having fallen into the ductular lumen. These findings suggest that Fas and FasL expressed in ducts and acini of chronic sialadenitis in SS patients induce apoptosis, possibily in an autocrine and/or paracrine manner.

Apoptosis↗