Search PubMed⌕ Search

Biomedical subjects

T Taki

Publications and source records attributed to T Taki.

At least 109 records · Page 6Linked to original sources
PubMed1997

Immunohistochemically detected expression of motility-related protein-1 (MRP-1/CD9) in lung adenocarcinoma and its relation to prognosis.

Motility-related protein-1 (MRP-1)/CD9 is a trans-membrane glycoprotein closely associated with suppression of cell motility and reduced metastatic potential of some tumor cells. We currently report that, according to the RT-PCR method for MRP-1/CD9 gene expression, patients with low expression of MRP-1/CD9 in non-small-cell lung cancer, especially the adenocarcinoma type, showed short overall survival. Then, to determine accurately the prognostic value of MRP-1/CD9 product levels in lung-adenocarcinoma cells, we immunohistochemically investigated its expression in 132 lung-adenocarcinoma patients undergoing potentially curative surgery. Of these patients, 44 (33%) showed reduced expression of MRP-1/CD9 in cancer cells, and an inverse association was observed between its expression and factors associated with tumor progression, such as nodal involvement (p = 0.029) or stage (p = 0.028). Patients with reduced expression of MRP-1/CD9 showed a significantly worse prognosis in overall survival (p = 0.005) and disease-free survival (DFS; p < 0.0001) than those with stronger expression; and even among patients with stage-I disease, similar results were obtained (overall survival, p = 0.038; DFS, p = 0.012). In a multivariate analysis, immunohistochemical MRP-1/CD9-expression level was an independent prognostic factor for DFS (p = 0.021), but not for overall survival (p = 0.572). Thus, immunohistochemical MRP-1/CD9-expression level solely in lung-adenocarcinoma cells within the tumor tissue appears to be a prognostic factor for DFS, and may be useful for detecting a high-risk sub-group of recurrence during the post-operative clinical course of the disease.

Adult↗
PubMed1997

Microsatellite instability and mutated type II transforming growth factor-beta receptor gene in gliomas.

Microsatellite instability has been reported in familial cancer syndrome and in various kinds of human sporadic tumors. We investigated the replication error (RER) and mutation rate of the transforming growth factor-beta type II receptor (TGF-beta RII) gene to determine the frequency of the RER+ phenotype and elucidate the relation between the mutation of the TGF-beta RII gene and RER in the tumorigenesis of glioma. We screened genomic DNA from 40 gliomas, comprised from 24 glioblastomas (GB), 11 anaplastic astrocytomas (AA) and five astrocytomas (AS) and compared the results with DNA from corresponding leukocytes. Seven of the 40 (18%) gliomas had the RER+ phenotype: five (21%) of 24 GB and two (18%) of 11 AA. In six gliomas we detected mutation of the TGF-beta RII gene. Five (71%) of seven RER+ and one (3%) of 33 RER-tumors had one A deletion in the (A)10 repeat of the TGF-beta RII gene. No mutations were detected in the (GT)3 repeat area of the TGF-beta RII gene. As the normal cells of these glioma patients had no mutations, we concluded that the mutations were somatic. We posit that the observed mutations inactivate the receptor through a frameshift mutation resulting in protein truncation. Our data suggest that the TGF-beta RII (A)10 repeat may be one area of genomic instability in the early stages of malignant glioma tumorigenesis.

Astrocytoma↗
PubMed1997

Detection of chimeric mRNAs by reverse transcriptase-polymerase chain reaction for diagnosis and monitoring of acute leukemias with 11q23 abnormalities.

Recurrent translocations involving chromosome band 11q23 are often found in human acute leukemias. Recently, the MLL gene on 11q23 and 10 partner genes involved in these translocations have been cloned and characterized. We performed a reverse transcriptase-polymerase chain reaction (RT-PCR) to detect the resultant der(11) chimeric mRNAs of the 3 types of 11q23 translocations including t(4;11), t(9;11), or t(11;19), in 14 leukemia patients with MLL gene rearrangements. At diagnosis or relapse, chimeric mRNA could be detected in all of the 4 patients with t(4;11), 2 of 3 with t(9;11), 2 of 3 with t(11;19), and 1 of 4 with unsuccessful karyotype. In 5 patients, we could monitor minimal residual disease (MRD) serially through the clinical course. One patient, in whom chi-meric mRNA was detected during complete remission (CR) just after the induction chemotherapy, relapsed within 2 months and died, while 2 patients in which chimeric mRNA was not detected remained in CR from 10-23 months. These findings suggest that RT-PCR is a useful approach for detecting which partner gene is involved in the translocation and monitoring MRD in patients with MLL gene rearrangement. Nonetheless, the clinical relevance of MRD evaluation by RT-PCR monitoring remains controversial. Long-term and prospective investigation of a larger series of patients is needed to confirm the clinical significance of monitoring MRD by RT-PCR method.

Acute Disease↗
PubMed1997

Fibronectin-mediated cell migration promotes glioma cell invasion through chemokinetic activity.

In order to investigate the biological role of fibronectin in glioma cell invasion, we studied the relation between migratory responses or adhesiveness of glioma cells to fibronectin and the in vitro invasion in three human malignant glioma cell lines, A172, T98G and U373MG. All these cell lines chemotactically migrated in a dose-dependent manner to fibronectin in concentrations ranging from 0.5 to 10 microg/ml, with A172 cells showing the strongest migration and U373 cells the weakest. Checkerboard analyses demonstrated that A172 and T98G cells showed much stronger chemokinetic responses to fibronectin than U373MG cells. In contrast to the migratory responses, A172 and U373MG cells showed an almost equally high adhesion to fibronectin and T98G cells a low adhesion. The degree of expression of the integrin alpha5 subunit correlated well with the strength of glioma cell adhesion to fibronectin rather than that of migration to the molecule. Furthermore, the cell adhesion to fibronectin was almost completely inhibited by arginine-glycine-aspartic acid (RGD)-containing peptides, but the fibronectin-stimulated cell migration was only partially inhibited. An in vitro invasion assay disclosed that U373MG cells invaded the artificial basement membrane barrier the most and A172 cells the least. However, addition of fibronectin to the glioma cells markedly enhanced the invasive activity of A172 and T98G cells but had little effect on that of U373MG cells. These results indicate that fibronectin-stimulated migration can be one of the factors promoting invasiveness of glioma cells and that the chemokinetic activity of fibronectin may play a crucial role in glioma invasion through conferring motor-driving force on the glioma cells.

Cell Adhesion↗
PubMed1997

Alterations of p16 and p15 genes in acute leukemia with MLL gene rearrangements and their correlation with clinical features.

p16 and p15 genes are putative tumor suppressor genes located on chromosome 9p21. In acute leukemias, alterations of p16 and p15 genes have been reported to occur exclusively in lymphoid lineage. We analyzed alterations of p16 and p15 genes in 46 acute leukemias with MLL gene rearrangements by Southern blot analysis, and investigated the association with clinical characteristics. We identified homozygous deletion of p16 and p15 genes in five (19%) of 27 acute lymphoblastic leukemias (ALLs) and in two (11%) of 19 acute myeloid leukemias (AMLs). Patients with homozygous deletion of p16 and p15 genes showed higher average leukocyte counts (343 x 10(9)/l vs 271 x 10(9)/l) and lower estimated 2-year survival rates than those with normal p16 and p15 genes (14.3 vs 30.7%), although the differences were not statistically significant. In addition, we investigated mutation of p16 gene by polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) in 31 patients, but no mutation was found in the patients tested. Our results suggest that alterations of p16 and p15 genes are involved in a subset of acute leukemias with MLL gene rearrangement not only of lymphoid but also of myeloid phenotype. Homozygous deletion of p16 and p15 genes may be a possible adverse prognostic factor, although further analysis would be needed to confirm it.

Adolescent↗
PubMed1997

gp49B1, an inhibitory signaling receptor gene of hematopoietic cells, is induced by leukemia inhibitory factor in the uterine endometrium just before implantation.

Leukemia inhibitory factor (LIF) is a cytokine involved in hematopoiesis, neuropoiesis, and embryogenesis. Transcriptional activation of various genes occurs subsequent to LIF signal transduction in its target cells. Using the mRNA differential display method, a LIF-inducible gene was isolated from LIF-stimulated M1 murine myeloid leukemia cells. By DNA sequencing, this gene turned out to be gp49B1, which has been reported as an inhibitory signaling receptor to attenuate mast cell activation. Because gp49B1 expression was limited to the uterus of a pregnant mouse, its uterine expression was examined especially in relation to LIF expression during pregnancy. gp49B1 was expressed specifically on day 4.0 of pregnancy, as was LIF, and the site of the most abundant expression of LIF and gp49B1 mRNA was the luminal epithelium of the uterine endometrium. These findings suggest that the gp49B1 expression in the uterine endometrium is induced just before implantation by paracrine and/or autocrine effects of LIF. Considering its function as an inhibitory signaling receptor on mast cells, a possible role for gp49B1 on the surface of the uterine endometrium as an immunoreceptor that allows blastocyst attachment is proposed.

Animals↗
PubMed1997

Intraductal ultrasonography of the pancreas: development and clinical potential.

Intraductal ultrasound (IDUS) probes mounted with 30 MHz or 20 MHz transducers were evaluated in the diagnosis of 239 patients with pancreatic disease (including 48 cancers, 90 mucin-producing tumors, seven islet-cell tumors, two metastatic pancreatic tumors, seven serous cystadenomas, one pancreatic teratoma, three solid cystic tumors, 49 cases of chronic pancreatitis, 25 cases of focal pancreatitis, and seven cases of pancreatolithiasis). The probe was inserted via the papilla into the main pancreatic duct. In terms of resolution, IDUS at 20 MHz was able to image cystic lesions of less than 30 mm in diameter and solid lesions of less than 20 mm in diameter. With regard to vessels, IDUS was able to image the entire cross-section of the portal vein and other large veins. IDUS was useful in detecting carcinoma in situ and small tumors, in assessing the intraductal spread of the tumor and its pancreatic parenchymal invasion in mucin-producing tumors of the main duct, and in assessing the indications for surgery by revealing mural nodules in mucin-producing tumors of the ductal branches. IDUS was also useful in evaluating the feasibility of partial resection of the tumor in mucin-producing tumors of the ductal branches and pancreatic islet-cell tumors, in accurately locating multiple lesions in pancreatic islet-cell cancer, and in differentiating benign from malignant cases of localized stenosis of the main pancreatic duct related to pancreatic stenting. With IDUS, the site of pancreatic stones could be identified in order to assess the need for endoscopic treatments such as stenting of the pancreatic duct and the bile duct, and the use of pulsed-dye laser treatment under pancreatoscopy for pancreatic stones. Acute pancreatitis as a complication occurred in one of the 239 patients who underwent IDUS (0.4%). An awareness of the limitations and usefulness of IDUS in evaluating pancreatic diseases can contribute to the treatment of these conditions.

Aged↗
PubMed1997

Diagnosis of mucin-producing tumor of the pancreas with an intraductal ultrasonographic system.

The purpose of this study is to examine the usefulness of intraductal ultrasonography at a frequency of 20 or 30 MHz in the diagnosis of mucin-producing tumor. The subjects were 66 patients with mucin-producing tumor (10 with main pancreatic duct type tumor and 56 with branch type tumor) who had also undergone endoscopic ultrasonography. In main pancreatic duct type tumors, we could diagnose the extent of the tumor and evaluate the invasion of the tumor into the pancreatic parenchyma in all seven patients who had undergone resection (three invasive tumors, four noninvasive tumors). Sixteen of 32 resected branch type tumors showing mural nodules with intraductal sonography were carcinoma or adenoma. On comparing intraductal and endoscopic ultrasonography in the rate of detecting nodules, in five tumors (one carcinoma and four adenomas), nodules were detected only with intraductal ultrasonography. In conclusion, intraductal ultrasonography is very useful for the diagnosis in the main pancreatic duct type tumor and in the detection of mural nodules in the branch type tumor.

Adenoma↗
PubMed1997

[Identification of impaired cholesterol biosynthesis in a Japanese patient of Smith-Lemli-Opitz syndrome].

We reported the decreased level of cholesterol as well as the elevated levels of 7- and 8-dehydrocholesterol in the serum and erythrocytes of a Japanese patient with Smith-Lemli-Opitz syndrome. These findings suggested that the detection of these precursors of cholesterol synthesis should become an important biochemical parameter for this syndrome in which clinical features are not always obvious.

Adult↗
PubMed1996

Fusion of the MLL gene with two different genes, AF-6 and AF-5alpha, by a complex translocation involving chromosomes 5, 6, 8 and 11 in infant leukemia.

We analysed a complex translocation involving chromosomes 5, 6, 8 and 11 in a case of infant leukemia. Molecular analysis of the MLL gene revealed that MLL was fused with two different genes, AF-6 on chromosome 6q27 and AF-5alpha. AF-5alpha, the 11th partner gene fused with MLL, is a novel gene mapped to chromosome 5q12, which encodes a 31 kDa protein of 269 amino acids and contains a possible nuclear targeting sequence, a potential leucine zipper dimerization motif and an alpha-helical coiled-coil domain. In situ hybridization and molecular cloning analyses demonstrated that two different types of chromosomal recombination had occurred in the cells. One was a three-way translocation among chromosomes 6, 8 and 11, and the other was an insertion of a chromosome 5-derived segment into the breakpoint of chromosomes 8 and 11. Accordingly, the karyotype was defined as del(5)(q11.2q12), der(6)t(6;8) (q27;q11.2), der(8)(8pter-->8q11.2::5q11.2-->5q12::11q23-->++ +11qter), der(11)t(6;11) (q27;q23). Thus, the MLL gene created two different fusion mRNAs, since the chromosome 11 split into two different chromosomes 5 and 6. This is the first report demonstrating fusion of the MLL gene with two different genes by a complex translocation.

Base Sequence↗
PubMed1996

Antisense inhibition of the RAD51 enhances radiosensitivity.

The mammalian RAD51 gene is a homologue of the yeast RAD51 and E. coli RecA genes, which are involved in recombination and DNA repair. We examined the role of RAD51 protein in mouse cells using RAD51 antisense phosphorothioate oligonucleotides (ODNs). The extraluminal delivery of 50 nM or 100 nM of antisense ODNs with lipofection to mouse cells resulted 90% suppression of RAD51 protein expression. The antisense ODNs significantly inhibited the cell growth and the treated cells became more sensitive to gamma-irradiation than the control groups. These results indicate mouse RAD51 plays an essential role in cell proliferation and radioresistant activity.

Animals↗
PubMed1996

Cell cycle-dependent expression of the mouse Rad51 gene in proliferating cells.

The mouse Rad51 gene is a mammalian homologue of the Escherichia coli recA and yeast RAD51 genes, both of which are involved in homologous recombination and DNA repair in mitosis and meiosis. The expression of mouse Rad51 mRNA was examined in synchronized mouse m5S cells. The Rad51 transcript was observed from late G1 phase through to M phase. During the period of late G1-S-G2, the RAD51 proteins were observed exclusively in nuclei. Activation by mitogens of T cell and B cell proliferation in spleen induced the expression of Rad51 mRNA. By immunohistochemical analyses, in mouse RAD51 protein was detected in proliferating cells: spermatogonia in testis, immature T cells in thymus, germinal center cells of the secondary lymphatic nodules of spleen and intestine, follicle cells in ovary and epithelial cells in uterus and intestine. It was also expressed in spermatocytes during early and mid-prophase of meiosis and in resting oocytes before maturation. Thus, mouse Rad51 expression is closely related to the state of cell proliferation and is presumably involved in DNA repair coupled with DNA replication, as well as in meiotic DNA recombination in spermatocytes.

Animals↗
PubMed1996

Correlation of KAI1/CD82 gene expression with good prognosis in patients with non-small cell lung cancer.

As part of our evaluation of members of the transmembrane 4 super-family as possible prognostic predictors, we performed a retrospective study on the expression of the recently identified KAI1 gene by tumors of the lung. This gene, which is identical to CD82, suppresses tumor metastasis of prostate cancer, and its decreased expression may be involved in malignant progression. We used reverse transcription-PCR to analyze tumor tissues from 151 lung cancer patients; 74 tumors were stage I, 17 were stage II, and 60 were stage III. Our results indicate that while 35 patients had tumors in which the KAI1/CD82 gene was conserved (positive), 116 patients had tumors with reduced gene expression (negative). The overall survival rate of patients with KAI1/CD82-positive tumors was significantly higher than that of patients with KAI1/CD82-negative tumors (77.4% versus 38.5%; P=0.002). Furthermore, the overall survival rate of patients with KAI1/CD82-positive adenocarcinoma was also much higher than that of individuals whose adenocarcinoma had reduced KAI1/CD82 expression (73.4% versus 27.1%;P=0.009). Multivariate analysis with the Cox regression model indicated that KAII/CD82 positivity correlated best with the overall survival rate, except for lymph node status. Our data suggest that high KAII/CD82 gene expression by tumors of the lung may be associated with a good prognosis. These findings complement our earlier studies on MRP-1/CD9, another member of the transmembrane 4 superfamily, whose reduced expression in non-small cell lung cancer appears to be a factor of poor prognosis. This set of observations suggests that assessment of the expression status of KAI1/CD82 and MRP-1/CD9 by tumors may provide prognostic information on the clinical behavior of lung cancer.

Age Factors↗
PubMed1996

A simple assay method for bacterial binding to glycosphingolipids on a polyvinylidene difluoride membrane after thin-layer chromatography blotting and in situ mass spectrometric analysis of the ligands.

A simple assay method for bacterial binding to glycosphingolipids on a polyvinylidene difluoride (PVDF) membrane has been developed. Glycosphingolipids were separated on a high-performance thin-layer chromatography (HPTLC) plate and transferred onto a PVDF membrane by TLC blotting [Taki, T., Handa, S., and Ishikawa, D. (1994) Anal. Biochem. 221, 312-316]. The PVDF membrane was blocked with phosphate-buffered saline containing 4% casein and 0.1% methionine and overlaid with 35S-labeled Escherichia coli possessing K99 fimbriae (E. coli K99) at 37 degrees C for more than 2 h. Binding of the 35S-labeled E. coli K99 was detected with a bioimaging analyzer. Radioactivities were located on the bands corresponding to N-glycolylneuraminic acid containing glycosphingolipids such as sialylparagloboside, GM2, and GM3 with hydroxy fatty acid in ceramide moiety, and a weak binding was detected on the band of N-acetylneuraminylparagloboside. Furthermore, an in situ mass spectrometric analysis of the ligand glycosphingolipids on the membrane was demonstrated. The present method has several advantages compared with the overlay binding assay on the HPTLC plate as follows: (i) the method is simple and rapid; (ii) the membrane is easy to handle; (iii) binding is clear with low background; (iv) a small amount of [35S]methionine is required; and (v) sensitive ligand characterization can be done by in situ mass spectrometric analysis.

Bacterial Adhesion↗