Biomedical subjects

Masakazu Ueda

Publications and source records attributed to Masakazu Ueda.

47 records · Page 3Linked to original sources

PubMed2002

Clinical significance of telomerase activity in peripheral blood of patients with esophageal squamous cell carcinoma.

BACKGROUND: The presence of tumor cells in the blood stream is considered evidence of a high risk of distant organ metastasis. We examined the usefulness of telomerase activity in peripheral blood polymorphonuclear cells as an indicator of distant metastasis in patients with esophageal squamous cell carcinoma. METHODS: Telomerase activity was measured in the peripheral blood mononuclear cell and polymorphonuclear cell fractions obtained from blood samples of healthy volunteers mixed with squamous cell carcinoma cell lines, and cell distribution was analyzed by flow cytometry. Then telomerase activity of forty-two polymorphonuclear cell fractions obtained from esophageal squamous cell carcinoma patients was measured. RESULTS: Telomerase activity was detected in polymorphonuclear cell fractions and cell distribution analysis revealed the presence of esophageal squamous cell carcinoma cells. Organ metastasis was detected in 7 (78%) of the 9 patients with telomerase-positive polymorphonuclear cell fractions as opposed to only five (15%) of the 33 with telomerase-negative cases, and there was a significant positive correlation between telomerase activity and organ metastasis (p < 0.0008). CONCLUSIONS: Measurement of telomerase activity in the polymorphonuclear cell fractions is useful for identifying a high risk group for distant organ metastasis in patients with esophageal squamous cell carcinoma.

Aged↗

PubMed2002

Reactive oxygen species and vascular cell adhesion molecule-1 in distant organ failure following bile duct obstruction in mice.

Pulmonary injury with leukocyte infiltration is a frequent occurrence in obstructive cholangitis patients. We wished to evaluate the roles of reactive oxygen species and vascular cell adhesion molecule-1 (VCAM-1) in this distant organ failure. Wild type (WT) and transgenic (SODtg) mice overexpressing superoxide dismutase underwent bile duct ligation and transection (BDL). VCAM-1 expression was quantified, and histopathology was assessed for the liver and lung. BDL resulted in increased leukocyte infiltration to the lung at five days in WT mice. VCAM-1 expression significantly increased in WT mouse liver at three days and WT mouse lung at five days. When these same experiments were performed in SODtg mice, these increases in leukocyte infiltration and VCAM-1 expression in lung were significantly attenuated. These data suggest that reactive oxygen species produced in response to BDL may up-regulate VCAM-1 expression in the lung and play an important role in the pathophysiology of this pulmonary injury.

Animals↗

PubMed2002

Growth inhibition of mammalian cells by eosinophil cationic protein.

Eosinophil cationic protein (ECP), one of the major components of basic granules of eosinophils, is cytotoxic to tracheal epithelium. However, the extent of this effect on other cell types has not been evaluated in vitro. In this study, we evaluated the effect of ECP on 13 mammalian cell lines. ECP inhibited the growth of several cell lines including those derived from carcinoma and leukemia in a dose-dependent manner. The IC(50) values on A431 cells, MDA-MB-453 cells, HL-60 cells and K562 cells were estimated to be approximately 1-5 microm. ECP significantly suppressed the size of colonies of A431 cells, and decreased K562 cells in G1/G0 phase. However, there was little evidence that ECP killed cells in either cell line. These effects of ECP were not enhanced by extending its N-terminus. Rhodamine B isothiocyanate-labeled ECP started to bind to A431 cells after 0.5 h and accumulated for up to 24 h, indicating that specific affinity for the cell surface may be important. The affinity of ECP for heparin was assessed and found to be reduced when tryptophan residues, one of which is located at a position in the catalytic subsite of ribonuclease in ECP, were modified. The growth-inhibitory effect was also attenuated by this modification. These results suggest that growth inhibition by ECP is dependent on cell type and is cytostatic.

Animals↗

PubMed2002

TFDP1, CUL4A, and CDC16 identified as targets for amplification at 13q34 in hepatocellular carcinomas.

We carried out molecular cytogenetic characterization of 11 cell lines derived from hepatocellular carcinomas (HCCs) and 51 primary HCCs. Comparative genomic hybridization (CGH) revealed frequent amplification at 13q34, where we had detected amplification in several other types of tumor, including esophageal squamous cell carcinomas (ESC). Previously, we suggested possible involvement of TFDP1, encoding a transcription factor DP-1, in the 13q34 amplification observed in a primary ESC. Therefore, we investigated amplifications and expression levels of 5 genes mapped on the amplified region, including TFDP1, for exploring amplification targets at 13q34 in HCCs. 3 of those genes, TFDP1, CUL4A (cullin 4A), and CDC16 (cell division cycle 16), showed distinct amplification and consequent over-expression in some cell lines. Moreover, each was amplified in 3 or 4 of the 51 primary HCCs, and all 3 were amplified in 2 tumors, in which their expression patterns correlated with amplification patterns. To elucidate the functional role of TFDP1 in HCC, we examined expression levels of genes downstream of TFDP1 with real-time quantitative polymerase chain reaction (PCR). Expression of cyclin E gene (CCNE1) correlated closely with that of TFDP1 in not only cell lines, but also primary tumors. Treatment of HCC cells with the antisense oligonucleotide targeting TFDP1 resulted in down-regulation of CCNE1, suggesting that TFDP1 overexpression led to up-regulation of CCNE1 that encoded a positive regulator for cell cycle G1/S transition. In conclusion, our findings suggest that TFDP1, CUL4A, and CDC16 are probable targets of an amplification mechanism and therefore may be involved, together or separately, in development and/or progression of some HCCs.

Apc6 Subunit, Anaphase-Promoting Complex-Cyclosome↗

PubMed2002

Immunosuppressive and anticancer effect of a mammalian ribonuclease that targets high-affinity interleukin-2-receptors.

OBJECTIVE: To target high-affinity interleukin (IL)-2 receptors involved in lymphocyte proliferation processes such as allograft rejection, autoimmune disorders, and certain haematological malignancies, using a minimally immunogenic mammalian-derived enzyme, bovine RNaseA, which becomes cytotoxic on entering cytoplasm. DESIGN: Laboratory study. SETTING: Teaching hospital, Japan. MATERIAL: Human lymphocytes isolated from healthy histoincompatible donors in mixed lymphocyte cultures or stimulated with phytohemagglutinin (PHA) to promote IL-2Ralpha expression. MJ, an HTLV-1-infected malignant T-cell line that overexpresses IL-2Ralpha, and the IL-2Ralpha-negative cell lines MOLT-4F and MT-1, were used as controls. INTERVENTIONS: Bovine RNaseA was chemically conjugated to 7G7B6, a monoclonal antibody to the alpha-chain of human IL-2 receptors, and several concentrations of the conjugates were added to the lymphocyte cultures. MAIN OUTCOME MEASURES: Inhibition of cell proliferation as a percentage of 3H-thymidine incorporation in 24 hours. RESULTS: 7G7B6-RNaseA dose-dependently inhibited cell proliferation in PHA-stimulated human lymphocytes at a 50% inhibitory concentration (IC50) of 2 x 10(-7) M. whereas RNase alone and RNase plus antibody had no inhibitory effect. 7G7B6-RNaseA also dose-dependently inhibited the human mixed lymphocyte reaction at an IC50 of 2 x 10(-6) M, whereas RNase alone did not. The conjugate also inhibited cell proliferation in MJ cells, a cell line that is infected with HTLV-I and overexpresses the high-affinity IL-2 receptor, at an IC50 of 5 x 10(-7) M. However the conjugate had no inhibitory effect on the IL-2 receptor non-expressing human T-cell lymphoblastic leukaemia cell lines MOLT-4F or MT-1. CONCLUSION: 7G7B6-RNaseA can inhibit cell proliferation in antigen- or mitogen-stimulated lymphocytes that overexpress high-affinity IL-2 receptors, and it may be safer than conventional chemotherapy or immunotoxins in the treatment of transplant rejection, certain lymphocytic malignancies, and other IL-2R-associated diseases, because it contains a mammalian cytotoxic enzyme.

Animals↗

PubMedDate not supplied

The cytotoxicity of a conjugate composed of human epidermal growth factor and eosinophil cationic protein.

BACKGROUND: Conventional targeted therapy with foreign proteins is highly immunogenic. In this study, we developed targeted therapy composed of human endogenous proteins and evaluated its efficacy in vitro. MATERIALS AND METHODS: Human epidermal growth factor (EGF) was chemically linked to human eosinophil cationic protein (ECP). The cytotoxicity of the EGF-ECP conjugate was evaluated by MTT assay. RESULTS: The conjugate showed dose-dependent cytotoxicity on EGF receptor (EGFR)-overexpressing BT-20 cells with an IC50 of 1.5 x 10(-7) M, whereas the IC50 of ECP alone was almost 10(-4) M. The conjugate had no detectable cytotoxicity against EGF receptor-deficient H69 cells. Excess EGF protected BT-20 cells from the cytotoxicity of the conjugate. Comparing the cytotoxicity and the level of EGFR expression, the cytotoxicity of the conjugate was positively correlated with the level of EGFR expression of each cell line. CONCLUSION: Conjugates composed solely of human proteins might be useful with less immunogenicity and less toxicity than the conventional immunotoxins for targeted therapy.

Blood Proteins↗

PubMedDate not supplied

Platelets counts closely correlate with the disease-free survival interval of pancreatic cancer patients.

BACKGROUND/AIMS: We investigated the relationship between preoperative platelets count and the outcome of pancreatic cancer patients. METHODOLOGY: We retrospectively reviewed the clinical records of 105 patients with invasive ductal carcinoma of the pancreas who underwent radical resection at our institution over a 20-year period. The patients were divided into two groups based on their preoperative platelets counts: a group with thrombocytosis (> or = 40x10(4)/mL) and a group with non-elevated platelets counts (< 40x10(4)/mL). Histopathological findings, survival rates, recurrence patterns, and disease-free survival intervals were compared between the two groups. RESULTS: The outcome of the group with thrombocytosis was significantly poorer than that of the group with non-elevated platelets counts (p=0.043). The mean disease-free interval of patients with thrombocytosis was 4.9 months as opposed to 46.5 months for those with non-elevated platelets counts (p=0.006). Patients were classified into four groups according to changes in platelets counts after surgery. Consistently, the outcome of the group with both pre- and postoperative non-elevated platelets counts was the best compared to groups with post- and/or postoperative thrombocytosis. CONCLUSIONS: Our clinical data suggest that high platelets counts in the preoperative and postoperative period may be associated with a poor outcome and shortening of postoperative disease-free survival interval.

Adult↗

PubMedDate not supplied

Endoscopic ultrasonography of nonfunctioning pancreatic islet cell tumors with histologic correlation.

BACKGROUND/AIMS: Preoperative differentiation of benign and malignant pancreatic nonfunctioning islet cell tumors remains problematic. The present study aimed to evaluate endoscopic ultrasonography (EUS) features of benign and malignant tumors with histologic correlation. METHODOLOGY: Ten patients with surgically resected nonfunctioning pancreatic islet cell tumors were retrospectively reviewed. RESULTS: EUS demonstrated a homogenous hypoechoic (n=2) or hyperechoic (n=1) mass in the 3 benign tumors. EUS showed a hypoechoic mass with an irregular central hyperechoic portion (n=4), a hyperechoic mass with an irregular central hypoechoic portion (n=1), a cystic mass with a large irregular internal hypoechoic portion (n=1), or a hypoechoic mass within the entire lumen of the main pancreatic duct (MPD) (n=1) in the 7 malignant tumors. Histologically, the irregular central portions of the malignant tumors corresponded to necrosis, hemorrhage, fibrosis with hyalinosis, cystic degeneration, and/or calcification. Complete obstruction of the main pancreatic duct on EUS was observed in the 2 malignant tumors. The echogenicity of the tumors was closely associated with arrangement of tumor cells and quantity of fibrous stroma. CONCLUSIONS: Heterogeneous internal structures and complete obstruction of the main pancreatic duct are considered as important EUS features that are suggestive of malignancy in nonfunctioning pancreatic islet cell tumors.

Adult↗

PubMedDate not supplied

Long-term survival of intrahepatic cholangiocarcinoma with hilar lymph node metastasis and portal vein involvement.

We report the case of a very rare 6-year disease-free survivor of intrahepatic cholangiocarcinoma with hilar lymph node metastasis and portal vein involvement. A 76-year-old female with liver dysfunction was referred to our institution. Contrast-enhanced computed tomography showed a 5-cm low-density tumor with irregular marginal enhancement in the left and caudate lobes of the liver. Cholangiography revealed complete obstruction of the left hepatic bile duct. Angiography showed obstruction of the left branch of the portal vein. Metastasis to the hilar lymph nodes was disclosed at surgery. The patient underwent left hepatectomy with caudate lobectomy, resection of the extrahepatic bile duct, and lymphadenectomy. The total vascular exclusion of the liver was used for hepatectomy and reconstruction of the portal vein. Microscopically, the tumor was a poorly differentiated adenocarcinoma with many infiltrating lymphocytes, and extensive necrosis was present within the tumor. The experience gained in the present case suggests that aggressive surgery may be a potential approach to provide a hope of long-term survival for patients with intrahepatic cholangiocarcinoma despite the presence of regional lymph node metastasis and vascular invasion.

Aged↗

PubMedDate not supplied

Identification of a new breast cancer-related gene by restriction landmark genomic scanning.

BACKGROUND: Molecular genetic analyses have demonstrated the importance of the accumulation of genomic changes in the etiology of cancer and, additionally, have identified valuable genetic markers for certain cancers. Although several prognostic markers have already been identified for breast cancer, it is clear that others remain to be identified. MATERIALS AND METHODS: Fourteen breast cancer samples and non-cancerous counterparts were applied to restriction landmark genomic scanning (RLGS) and 6 breast cancer cell lines (MCF-7, MDA-MB-435, T-47D, MDA-MB-231, SK-BR-3 and BT-20) and 9 cancer tissue samples were applied to reverse transcnptionalpolymerase chain reaction (RT-PCR) for screening of novel genetic alterations. RESULTS: Two spots were identified on the RLGS profiles of cancerous tissue that differed from those of normal tissue. Nucleotide sequencing and homology search analysis showed that these spots represented the voltage-dependent calcium channel alpha1H subunit gene (CACNA1H gene) and a locus immediately downstream of the growth factor receptor-binding protein 7 (GRB7) gene. Expression of the CACNA1H gene was confirmed by RT-PCR. CONCLUSION: Two genes, Grb7 and CACNA1H, were identified by RLGS. The expression of CACNA1H in breast cancer was confirmed for the first time.

Adult↗

PubMedDate not supplied

Mechanisms of the growth-inhibitory effect of the RNase-EGF fused protein against EGFR-overexpressing cells.

BACKGROUND: We previously showed the usefulness of a fused protein of human pancreatic ribonuclease1 (hRNase1) with human epidermal growth factor (hEGF) for molecular targeting of EGF receptor (EGFR)-overexpressing cells. In this study, the mechanisms underlying the inhibition of cell growth by RNase-EGF fused proteins was confirmed. MATERIALS AND METHODS: Des.1-7 hRNase1 was genetically fused to hEGF. The fused proteins were expressed and isolated from Escherichia coli. The internalization of hRNase1-hEGF was confirmed by confocal fluorescence microscopy. The growth-inhibitory effect of the fused proteins was evaluated by MTT assay. RESULTS: FITC-labelled hRNase1-hEGF was internalized into EGFR-overexpressing A431 cells. The internalization was not observed in A431 cells pre-treated with hEGF and EGFR-deficient H69 cells. The growth-inhibitory effect of des.1-7 hRNase1-hEGF against A431 cells was statistically significantly more pronounced than that of hRNase1-hEGF. CONCLUSION: RNase-EGF fused proteins are internalized through EGFR and inhibit cell growth by exerting their ribonucleolytic activity in the cytosol.

Amino Acid Sequence↗