Biomedical subjects

Toshikatsu Shibata

Publications and source records attributed to Toshikatsu Shibata.

12 recordsLinked to original sources

PubMed2006

An inhibitory effect of A20 on NF-kappaB activation in airway epithelium upon influenza virus infection.

Influenza is a major disease in humans. The reemergence of avian influenza A viruses has indicated that hyperinflammatory responses are closely related to the severity of disease. Influenza virus infection induces nuclear transcription factor kappaB (NF-kappaB) activation. NF-kappaB and NF-kappaB-dependent gene products promote lung inflammation and injury. Therefore, it is important to investigate the means to attenuate NF-kappaB activation. A20 is a cytoplasmic zinc finger protein that inhibits NF-kappaB activity, However, little is known about the role of A20 in influenza virus infection. Here, we have examined the role of A20 in influenza virus infection-induced NF-kappaB promoter activation in human bronchial epithelial cells. The results showed that (1) A20 protein and mRNA are inducible and expressed in the lung from mice and human bronchial epithelial cells upon influenza virus infection; (2) NF-kappaB promoter activation was induced in bronchial epithelial cells upon influenza virus infection; and (3) overexpression by transient transfection of A20 attenuated NF-kappaB promoter activation in bronchial epithelial cells. These results indicate that A20 may function as a negative regulator of NF-kappaB-mediated lung inflammation and injury upon influenza virus infection, thereby protecting the host against inflammatory response to influenza virus infection.

Animals↗

PubMed2005

Expression of homeodomain protein CDX2 in gallbladder carcinomas.

PURPOSE: Caudal-related homeobox protein CDX2 plays an important role in the regulation of cell proliferation and differentiation of the intestinal epithelium. CDX2 is associated with intestinal metaplasia and carcinomas of the stomach, but the role of CDX2 in gallbladder carcinogenesis remains unknown. METHODS: We analyzed the expression of CDX2 and intestinal apomucin MUC2 in gallbladder cancer cell lines at the mRNA level by the RT-PCR method. We also investigated the expression of CDX2 and MUC2 in 68 primary gallbladder carcinomas by the immunohistochemical staining method and compared the expression of CDX2 with the clinicopathological factors in the gallbladder carcinoma cases. RESULTS: Expression of CDX2 and MUC2 was found in three of four gallbladder cancer cell lines at the mRNA level. In addition, we found that CDX2 was absent in the normal gallbladder epithelium, but the CDX2 protein was expressed in 25 of the 68 (36.8%) gallbladder carcinomas. Interestingly, in the tubular type gallbladder carcinomas, the frequency of CDX2 expression was much higher in the well-differentiated type than the moderately and poorly differentiated types, the difference being statistically significant (P<0.01). CDX2 expression showed a relationship with expression of MUC2 (P<0.04) in the gallbladder carcinomas. CDX2 was expressed in intestinal metaplasia and dysplasia, which are hypothesized to be premalignant conditions. CONCLUSION: These results imply that CDX2 plays an important role in gallbladder carcinogenesis with intestinal differentiation.

Aged↗

PubMed2005

Immunohistochemical detection of telomerase reverse transcriptase (TERT) protein in benign and malignant tumor cells of the breast.

Telomerase activity is associated with immortality and is expressed in various malignant tumors. Telomerase reverse transcriptase (TERT) is a human telomerase catalytic subunit and is strongly correlated with telomerase activity. In this study, the expression of TERT was investigated by immunocytochemistry to determine whether it is a useful marker for differential diagnosis in benign or malignant breast tumors. We examined imprint smears prepared from 63 surgically resected breast lesions, and 27 cases of secretion or aspiration cytology smears had been routinely diagnosed. Eighteen of the 63 cases were examined for TERT mRNA and the correlation with expression of TERT protein was investigated. Expression of TERT protein was correlated with expression of TERT mRNA by in situ hybridization (p=0.044), suggesting that telomerase activity might be expressed with morphologic factors. In imprint smears and routine cytology smears, TERT-positive cases significantly tended to be malignant cases (p=0.014, p=0.033 respectively). Especially, in malignant imprint smear cases, positive expression of TERT was significantly correlated with lymph node metastasis (p=0.022). In conclusion, the expression of TERT protein might be a useful marker for differential diagnosis in malignant and benign breast tumors. In malignant cases, it could be a useful indicator for the assessment of potential of lymph node metastasis [corrected].

Biomarkers, Tumor↗

PubMed2005

The usefulness of immunostaining in washed cell cytological smears for differential diagnosis of B cell type malignant lymphoma.

We investigated the usefulness of immunostaining on washed cell cytological smears for the differential diagnosis of B-cell type malignant lymphoma. Twenty-eight cases with possible malignant lymphoma were examined. The tissues were squashed in a test tube of isotonic saline. The cell suspensions were then washed to remove non-specific soluble immmunoglobulin, and were smeared. Immunocytochemical staining for IgG, IgA, IgM, kappa and lambda was performed on the smears. As seen in the results, all cases of B cell lymphoma have a positive rate of 20% or over for kappa or lambda, and a kappa/lambda ratio of over 4.5 or a ratio of over 2.0 lambda/kappa, in the washed cell smears. Thus, it is possible to distinguish B cell lymphoma from the others by means of the results use as cut off scores. In addition, the rapid staining protocol in the present study was able to provide the results within 15 min. Therefore, it might be the most suitable method for the detection of immunoglobulin monoclonality in general laboratories.

Diagnosis, Differential↗

PubMed2004

Proposal for two strategies to prevent remnants of gastric cancers after endoscopic mucosal resections: fluorescein electronic endoscopy and rapid stump diagnosis based on pit patterns.

BACKGROUND: The aim of the present study was to establish strategies to prevent cancer remnants after gastric endoscopic mucosal resection (EMR). METHODS: Whether surgical stumps could be diagnosed by pit patterns was examined on 38 well-fixed EMR materials. Furthermore, a rapid stump diagnostic method, which enables pit patterns of EMR material to be observed within 10 min, was developed. This rapid stump diagnosis was tested in 6 EMR cases of early gastric cancers, one of which was absolutely obscure to routine endoscopy. Fluorescein electronic endoscopy had been performed to reveal the extent of this cancer before EMR. RESULTS: Adenocarcinomas showed irregular pit patterns that were significantly different from those of normal gastric mucosae. Among the 38 cases, all 20 EMR materials that were diagnosed as stump (-) and 5 that were diagnosed as stump (+), based on pit patterns, were confirmed by tissue sections to be stump (-) and stump (+), respectively. Six of the 13 EMR materials diagnosed as stump (+/-) by pit patterns were finally diagnosed as stump (+) by tissue sections. These data indicate that cancer remnants could be avoided if the stumps were judged positive or suspiciously positive just after EMR, and additional resections were continuously done until the stumps became negative. Rapid stump diagnosis based on pit patterns was successful in all 6 tested cases. The extent of the early gastric cancer that was absolutely obscure to routine endocscopy was clearly and exactly revealed by fluorescein electronic endoscopies done before EMR and subsequent rapid stump diagnosis. CONCLUSION: It is probable that fluorescein electronic endoscopy, as a precise preoperative examination, and rapid stump diagnosis, based on pit patterns, will become effective strategies to prevent cancer remnants after EMR.

Adenocarcinoma↗

PubMed2003

Analysis of epitope recognition of antibodies induced by DNA immunization against hemagglutinin protein of influenza A virus.

In an effort to find efficient DNA vaccine candidates, cDNA of influenza A virus hemagglutinin (HA) gene and several derived mutants were injected into mice using a gene gun. Mice immunized with HA1 DNA, with or without a membrane domain, showed a humoral immune response and the survival rate against homologous virus challenge was comparable to that of mice injected with HA DNA. In order to analyze epitopes recognized by antibodies induced by gene gun immunization, we used a binding assay employing the chimeric HA protein method. Serum antibodies of mice immunized with HA DNA recognized the HA1 domain but not the HA2 domain. In addition, antisera obtained from mice immunized with HA1 DNA reacted with each of the known antigenic sites on the HA1 domain, similar to the results obtained with HA DNA immunization.

Animals↗

PubMed2003

Unmutated immunoglobulin M can protect mice from death by influenza virus infection.

To elucidate the role of class switch recombination (CSR) and somatic hypermutation (SHM) in virus infection, we have investigated the influence of the primary and secondary infections of influenza virus on mice deficient of activation-induced cytidine deaminase (AID), which is absolutely required for CSR and SHM. In the primary infection, AID deficiency caused no significant difference in mortality but did cause difference in morbidity. In the secondary infection with a lethal dose of influenza virus, both AID-/- and AID+/- mice survived completely. However, AID-/- mice could not completely block replication of the virus and their body weights decreased severely whereas AID+/- mice showed almost complete prevention from the reinfection. Depletion of CD8+ T cells by administration of an anti-CD8 monoclonal antibody caused slightly severer body weight loss but did not alter the survival rate of AID-/- mice in secondary infection. These results indicate that unmutated immunoglobulin (Ig)M alone is capable of protecting mice from death upon primary and secondary infections. Because the titers of virus-neutralizing antibodies were comparable between AID-/- and AID+/- mice at the time of the secondary infection, a defect of AID-/- mice in protection of morbidity might be due to the absence of either other Ig classes such as IgG, high affinity antibodies with SHM, or both.

Animals↗

PubMed2003

Correlation between the expression of telomerase reverse transcriptase and proliferative activity in breast cancer cells using an immunocytochemical restaining method.

Telomerase activity is thought to contribute to the immortality of cancers. Recently, some investigators described a correlation between the activity of telomerase and the proliferative activity of cancer cells. The aim of this study was to evaluate the correlation between the expression of telomerase-associated protein and proliferative activity. Telomerase reverse transcriptase (TERT) is one of the proteins that correlates with telomerase activity. We investigated TERT protein and its mRNA, and examined the correlation between the TERT protein and Ki-67, which reflects proliferative activity with immunostaining, and its mRNA, which correlates with telomerase activity, using in situ hybridization. Imprint smears from 17 invasive ductal adenocarcinomas were investigated. In most cases positive for TERT mRNA, the percentage of TERT protein-positive cells was also high and was closely related to mRNA (P = 0.024). The positive rates of TERT for the cases with lymph node metastasis were significantly higher than those for the cases without metastasis (P = 0.046). The positivity of TERT protein also correlated significantly with the Ki-67-positive rate (r = 0.82). As the proliferation activity increased, the number of cells positive for both proteins also increased (r = 0.89). In conclusion, it was suggested that the expression of TERT protein is associated with the expression of Ki-67, and is concerned with maintenance of the high proliferative activity in cancer cells with aggressive proliferation.

Adult↗

PubMed2003

[Frequency of apoptotic cells and BAX positive cells in the lymph nodes of colorectal cancer patients with metastasis and micrometastasis].

It is regarded that the presence of micrometastatic(isolated) cancer cells is a forerunner of metastasis. We classified advanced colorectal cancers into 3 groups such as metastasis group in which distinct metastasis was identified in lymph nodes by HE stain, micrometastasis group which was negative for metastasis by HE stain but positive for micrometastasis by immunostain using antibody for cytokeratin, and non-metastasis group which was negative for both stains. We investigated proliferative activity of cells and frequency of apoptotic cells in the lymph nodes from each group. The frequency of apoptotic cells in the metastasis group was significantly lower than the other groups (p < 0.02), and correlated with expression of BAX protein. In conclusion, frequencies of apoptotic cells and BAX positive cells in the nodes of metastasis group were significantly lower than micrometastasis group. And it was suggested that those changes were correlated with inflow of isolated cancer cells and formation of metastatic foci in the lymph nodes, and may reflected the difference of immunological activity against cancer cells.

Apoptosis↗

PubMed2002

Fluorescein electronic endoscopy: a novel method for detection of early stage gastric cancer not evident to routine endoscopy.

BACKGROUND: Fluorescence endoscopy with fluorescein sodium in the stomach was evaluated by using a newly developed fluorescence electronic endoscopic system. METHODS: Sixteen patients with early stage gastric cancer diagnosed by white light endoscopy and chromoendoscopy underwent fluorescein electronic endoscopy before surgery. The resection specimens underwent thorough histopathologic evaluation. RESULTS: About 10 seconds after intravenous injection of fluorescein, fluorescence appeared and immediately spread throughout the gastric surface. A few minutes later, differentiated early stage gastric cancers with more abundant stroma than surrounding normal mucosa exhibited significantly stronger fluorescence, and those with less stroma exhibited weaker fluorescence than the surrounding normal mucosa. Undifferentiated early stage gastric cancers, in which the stroma became wider because foveolae were collapsed from malignant invasion, expressed stronger fluorescence intensity. In all cases, the borders of early stage gastric cancers were clearly demonstrated. Among the 16 patients, 6 accompanying flat lesions and 1 tiny lesion not evident by routine endoscopy were detected. The extent of the cancers, as determined by fluorescence endoscopy, were similar to those determined histopathologically. CONCLUSIONS: Fluorescein electronic endoscopy is useful in determining the extent within the mucosa of gastric cancers when this is obscure by standard endoscopic observation, and for detecting extremely early stage cancer that is not evident by conventional endoscopic observation.

Contrast Media↗

PubMed2002

[Correlation between expression of MMP-7 in gastric submucosal invasive carcinoma and lymph node micrometastasis].

To clarify the mechanism of tumor metastasis, lymph nodes micrometastasis and expression of MMP-7, which is related to lymph node metastases, were investigated in 45 submucosal, invasive gastric carcinomas. Metastases to lymph nodes were detected in 12 of 45 cases(26.7%) by HE stain. In 13 of 45 cases (28.9%), only micrometastases were detected by immunostaining with anti-cytokeratin antibody. The incidence of micrometastases was higher in poorly-differentiated carcinoma than well-differentiated carcinoma. Expression of MMP-7 was higher in metastasis positive cases than in negative cases. In poorly-differentiated cases, expression of MMP-7 was associated with micrometastasis. In conclusion, expression of MMP-7 may play an important role not only in tumor metastasis but in micrometastasis to lymph node especially in poorly-differentiated cases.

Humans↗

PubMedDate not supplied

Clinicopathologic roles of tumor-infiltrating lymphocytes and CD8-positive lymphocytes in lung cancer imprint smears in squamous cell carcinoma and adenocarcinoma.

OBJECTIVE: To investigate the presence of tumor-infiltrating lymphocytes (TILs) and CD8-positive lymphocytes (CD8s) in lung cancers and to examine the prognostic significance of their relationship with clinicopathologic parameters. STUDY DESIGN: Primary tumor imprint smears from 83 lung cancers were consecutively obtained at surgery at Tsuchiura Kyodo General Hospital between 1996 and 1998. TILs were observed in Papanicolaou-stained smears, and CD8s were immunocytochemically visualized. RESULTS: TILs were judged positive in 42 cases (51%), and 34 of 83 cases (41%) were positive for CD8s. There was no correlation between the frequency of TILs and CD8s. TILs assessed by Papanicolaou staining in 83 cases showed no correlation with any clinicopathologic factors. CD8s were observed more frequently in squamous cell carcinomas (SCCs) than other adenocarcinomas. A high frequency of CD8s was associated with lymph node metastasis (p = 0.043), stage (p = 0.025) and tumor differentiation (p = 0.03). TILs and CD8s made no significant difference in survival. However, in SCC the patients positive for TILs but negative for CD8s survived and had a significantly better prognosis than did the others (p = 0.037). CONCLUSION: CD8s were associated with tumor progression and development of malignancy in lung cancers. Especially in SCC, the cases had a high frequency of TILs. A low number of CD8s may correlate with a favorable prognosis.

Adenocarcinoma↗