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Y Niitsu

Publications and source records attributed to Y Niitsu.

At least 145 records · Page 8Linked to original sources
PubMed1995

CMV viraemia demonstrated in the serum of a patient with cytomegalovirus pneumonia.

We attempted to demonstrate the expression of cytomegalovirus (CMV) particles in the serum of an acute lymphocytic leukaemia patient with CMV pneumonia. The serum sample was applied to an affinity column coupled with human monoclonal antibody C23 which recognizes the envelope glycoproteins of CMV virus and neutralizes the viral activity. The DNA obtained from each fraction was amplified by double polymerase chain reaction (PCR) and analysed by gel electrophoresis. Bands were clearly observed in the eluted fraction. These results strongly suggest that CMV particles exist in the sera of patients with CMV pneumonia.

Base Sequence↗
PubMed1995

Loss of E-cadherin-dependent cell-cell adhesion due to mutation of the beta-catenin gene in a human cancer cell line, HSC-39.

Detachment of cell-cell adhesion is indispensable for the first step of invasion and metastasis of cancer. This mechanism is frequently associated with the impairment of either E-cadherin expression or function. However, mechanisms of such abnormalities have not been fully elucidated. In this study, we demonstrated that the function of E-cadherin was completely abolished in the human gastric cancer cell line HSC-39, despite the high expression of E-cadherin, because of mutations in one of the E-cadherin-associated cytoplasmic proteins, beta-catenin. Although immunofluorescence staining of HSC-39 cells by using an anti-E-cadherin antibody (HECD-1) revealed the strong and uniform expression of E-cadherin on the cell surface, cell compaction and cell aggregation were not observed in this cell. Western blotting (immunoblotting) using HECD-1 exhibited a 120-kDa band which is equivalent to normal E-cadherin. Northern (RNA) blotting demonstrated a 4.7-kb band, the same as mature E-cadherin mRNA. Immunoprecipitation of metabolically labeled proteins with HECD-1 revealed three bands corresponding to E-cadherin, alpha-catenin, and gamma-catenin and a 79-kDa band which was apparently smaller than that of normal beta-catenin, indicating truncated beta-catenin. The 79-kDa band was immunologically identified as beta-catenin by using immunoblotting with anti-beta-catenin antibodies. Examination of beta-catenin mRNA by the reverse transcriptase-PCR method revealed a transcript which was shorter than that of normal beta-catenin. The sequencing of PCR product for beta-catenin confirmed deletion in 321 bases from nucleotides +82 to +402. Southern blotting of beta-catenin DNA disclosed mutation at the genomic level. Expression vectors of Beta-catenin were introduced into HSC-39 cells by transfection. In the obtained transfectants, E-cadherin-dependent cell-cell adhesiveness was recovered, as revealed by cell compaction, cell aggregation, and immunoflourescence staining. From these results, it was concluded that in HSC-39 cells, impaired cell-cell adhesion is due to mutations in beta-catenin which results in the dysfunction of E-cadherin.

Antibodies, Monoclonal↗
PubMed1995

[Dysfunction of E-cadherin due to mutation of beta-catenin in a scirrhous gastric cancer cell line].

E-cadherin is a calcium dependent cell-cell adhesion molecule. In cancer tissue, detachment of the adhesion system is indispensable for invasion and metastasis of cancer cells. We have investigated mechanism of the dysfunction of E-cadherin-dependent cell-cell adhesion system in gastric carcinoma cells. Although the high expression of E-cadherin in a scirrhous gastric cancer cell line HSC-39, the function of E-cadherin was completely abolished. Western blotting of beta-catenin in HSC-39 cells demonstrated that a truncated beta-catenin was detected. The truncation was due to partial deletion of beta-catenin DNA. It was concluded that in HSC-39 loss of E-cadherin dependent cell-cell adhesion was due to mutation of beta-catenin gene.

Adenocarcinoma, Scirrhous↗
PubMed1995

[Hematopoietic stem cell transplantation].

Recent development of chemotherapy enabled us to cure patients with malignancies including leukemia, malignant lymphoma, choriocarcinoma, ovarian cancer, breast cancer and so on. In order to obtain the definite effect, the quantities of chemotherapeutic agents should be increased and the major lethal side effect caused by bone marrow failure should be avoided. For this purpose, hematopoietic stem cells derived from either bone marrow or peripheral blood can be used for the rapid recovery of neutropenia and thrombocytopenia. We prepared stem cells both from bone marrow and peripheral blood by anti-CD34 monoclonal antibody bound on magnetic beads column and administered into severe combined immunodeficiency (SCID) mouse. Four and 20 weeks after transplantation, mononuclear cells bearing human hematopoietic antigens and human immunoglobulin G were appeared in the circulation, suggesting that stem cells from peripheral blood also possess long-standing capability of maturation as well as those from bone marrow. We next conducted clinical study of high dose chemotherapy combined with peripheral blood stem cell transplantation for patients with poor risk choriocarcioma. By this treatment, 4 complete response (CR) and 4 partial response (PR) were obtained, whereas 2 progressive disease (PD), 1 no change (NC) and 5 PR were obtained by the previous conventional chemotherapies. The results obtained were promising and this treatment regimen may become a good modality for the complete treatment of chemotherapy curable tumors.

Adolescent↗
PubMed1995

Detection and quantification of soluble asialoglycoprotein receptor in human serum.

We describe the first evidence that soluble asialoglycoprotein receptors (AGPR) are present in human serum and that they are quantifiable by an enzyme-linked immunosorbent assay (ELISA). An affinity chromatography gel immobilized with monoclonal antibodies (McAbs) against human liver AGPR was mixed with normal sera, and the bound fraction was analyzed both by sodium dodecyl sulfate polyacrylamide gel electrophoresis and by Western blot analysis. Immunoreactive bands corresponding to 35 to 40 kd were obtained, which were lower than those of liver AGPR (41 kd and 46 kd). Soluble AGPR in human serum was able to bind to D-galactose-immobilized beads, indicating that the soluble AGPR remained ligand-binding activity. In order to quantify soluble AGPR, we established an ELISA using a monoclonal antibody (30220 McAb)-immobilized microplate and horseradish peroxidase-labeled F(ab')2 of another monoclonal antibody (30201 McAb). Reproducibility of intra- and interassay of the ELISA were 4% to 14% and 7% to 14%, respectively. Analytical recoveries ranged from 93% to 99%. The detection limit was estimated to be 0.1 micrograms/L. By nonparametolic analysis, a median and a 90% tile of serum AGPR level obtained from 283 normal volunteers were 0.4 micrograms/L and 2.4 micrograms/L, respectively.

Antibodies, Monoclonal↗
PubMed1994

Endogenous tumor necrosis factor functions as a resistant factor against adriamycin.

One of the mechanisms of cytotoxicity by tumor necrosis factor (TNF) and heat is the induction of reactive oxygen molecules. Cells producing endogenous tumor necrosis factor (enTNF) show resistance to the cytotoxicity of exogenous TNF and heat by inducing manganous superoxide dismutase (MnSOD) to scavenge the reactive oxygen molecules. Intracellular hydroxyl radical production is also involved in adriamycin-induced cytotoxicity. In this study, we therefore examined the possibility that enTNF may act as a protective protein against adriamycin-induced cytotoxicity in a manner similar to that in which it protects against exogenous TNF and heat. Adriamycin-sensitive L-M (mouse tumorigenic fibroblast) cells, originally expressing no enTNF, were transfected with an expression vector which directs the synthesis of non-secretory-type human TNF (enTNF). The stable transformants became resistant to adriamycin with increased levels of MnSOD. Conversely, when HeLa (human uterine cervical cancer) cells, which originally produce an appreciable amount of enTNF, were transfected with an anti-sense TNF mRNA expression vector to inhibit enTNF synthesis, their intracellular MnSOD activity was suppressed and adriamycin sensitivity was enhanced. However, no alterations in expression of multidrug-resistant gene products--P-170 glycoprotein, glutathione S-transferase pi (GST-pi) and the intracellular concentrations of glutathione (GSH)--were observed in these transfectants as compared to their parent cells. These results indicate that enTNF exerts its intracellular protective effect against adriamycin-induced cytotoxicity by the same mechanism as that against exogenous TNF and heat, namely scavenging reactive oxygen with induced MnSOD.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Suppressive effect of recombinant human Cu, Zn-superoxide dismutase on lung metastasis of murine tumor cells.

The inhibitory effect of recombinant human Cu++Zn++superoxide dismutase (rhSOD) on metastasis of tumor cells in the mouse was investigated. In an experimental pulmonary metastasis model employing Meth A cells as inoculum, significant inhibition of metastasis was obtained by intravenous pre- and post-administration of rhSOD. An inhibitory effect of rhSOD was also observed in a spontaneous pulmonary metastasis model with 3LL cells as the inoculum. rhSOD was not observed to have any significant effects on the platelet-aggregating activity of tumor cells, the adhesiveness of tumor cells to vascular components (endothelial cells, laminin and type-IV collagen), or the growth of tumor cells either in vitro or in vivo. However, rhSOD suppressed invasion of Meth A and 3LL cells into Matrigel (an artificially reconstituted basement membrane of collagen, laminin and heparan sulfate) in the presence of hypoxanthine and xanthine oxidase, in vitro producers of superoxide. Thus, the present study shows that rhSOD is able to inhibit both experimental and spontaneous pulmonary metastasis, possibly through the suppression of tumor cell invasion into the extracellular matrix.

Animals↗