Biomedical subjects

R Ueda

Publications and source records attributed to R Ueda.

At least 19 recordsLinked to original sources

PubMed2000

Aberrant overexpression of 53BP2 mRNA in lung cancer cell lines.

The p53-binding protein 2 (53BP2) was identified as a binding protein to a tumor suppressor p53. We examined the genetic aberrations of 53BP2 gene in various human cancer cell lines. Although no gross genomic alteration or mutation of 53BP2 gene was observed, 53BP2 mRNA levels were highly variable. There was no association between the 53BP2 mRNA level and the p53 status. When we examined sensitivities of these cell lines to DNA-damaging agents including UV irradiation, X-ray irradiation and cis-diamine-dichloroplatinum (CDDP), we found that higher 53BP2 mRNA expression was correlated with the sensitivity to these agents.

Apoptosis Regulatory Proteins↗

PubMed2000

In vivo treatment of mutant FLT3-transformed murine leukemia with a tyrosine kinase inhibitor.

Somatic mutation of the FLT3 gene, in which the juxtamembrane domain has an internal tandem duplication, is found in 20% of human acute myeloid leukemias and causes constitutive tyrosine phosphorylation of the products. In this study, we observed that the transfection of mutant FLT3 gene into an IL3-dependent murine cell line, 32D, abrogated the IL3-dependency. Subcutaneous injection of the transformed 32D cells caused leukemia in addition to subcutaneous tumors in C3H/HeJ mice. To develop a FLT3-targeted therapy, we examined tyrosine kinase inhibitors for in vitro growth suppression of the transformed 32D cells. A tyrosine kinase inhibitor, herbimycin A, remarkably inhibited the growth of the transformed 32D cells at 0.1 microM, at which concentration it was ineffective in parental 32D cells. Herbimycin A suppressed the constitutive tyrosine phosphorylation of the mutant FLT3 but not the phosphorylation of the ligand-stimulated wild-type FLT3. In mice transplanted with the transformed 32D cells, the administration of herbimycin A prolonged the latency of disease or completely prevented leukemia, depending on the number of cells inoculated and schedule of drug administration. These results suggest that mutant FLT3 is a promising target for tyrosine kinase inhibitors in the treatment of leukemia.

Animals↗

PubMed2000

MUM1/IRF4 expression as a frequent event in mature lymphoid malignancies.

MUM1/IRF4 is a myeloma-associated oncogene transcriptionally activated as a result of t(6;14)(p25,q32) chromosomal translocation and by virtue of its juxtaposition to the immunoglobulin heavy chain gene (IgH) locus. When this oncogene becomes non-functional, no activated B/T lymphocytes and Ig secreting plasma cells are observed, suggesting that MUM1/IRF4 is crucial for lymphoid development. Its expression was analyzed in both reactive lymphoid and lymphoma tissues by means of an immunohistochemical technique using specific goat antiserum against MUM1/IRF4. This analysis detected a 50 kDa MUM1 product whose localization was restricted to the nuclei of the lymphocytes. The MUM1+ cells in reactive lymph nodes were found to consist of plasma cells and a small fraction (approximately 7.9%) of B cells harboring CD20+CD38+, which were located in the light zone of the germinal center. MUM1 expression in peripheral blood B/T lymphocytes was upregulated by mitogenic stimuli, suggesting that MUM1 positivity represents the activated state of the B/T cells. In B cell non-Hodgkin's lymphoma (NHL), MUM1 expression was observed in 73.2% (30/41) of diffuse large B cell lymphoma (DLBCL), 20% (1/5) of marginal zone lymphoma (MZL) and 43% (3/7) of small lymphocytic lymphoma (SLL) cases, whereas it was not seen in any cases of mantle cell lymphoma (MCL) or follicle center lymphoma (FCL). Also, MUM1 was stained at high intensity in various types of T cell lymphomas including adult T cell leukemia/lymphoma (ATL/L) and anaplastic large cell lymphoma (ALCL) and in the majority of Hodgkin's diseases. Our results suggest that a major proportion of lymphomas comprise either physiologically or aberrantly activated neoplastic lymphocytes expressing the MUM1 protein.

B-Lymphocytes↗

PubMed2000

Quantitative expression of erythropoietin receptor (EPO-R) on acute leukaemia cells: relationships between the amount of EPO-R and CD phenotypes, in vitro proliferative response, the amount of other cytokine receptors and clinical prognosis. Japan Adult Leukaemia Study Group.

Expression of erythropoietin (EPO) receptor (EPO-R) was analysed in leukaemia cells from 150 patients with acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL). EPO-R was expressed in 81 (60%) out of 136 AML, and in vitro treatment with EPO led to proliferation of leukaemia cells in 13 (16%) out of 81 AML examined. EPO-R expression and in vitro response to EPO were observed in all subtypes of AML according to the French-American-British (FAB) classification. All eight patients with FAB-M6 expressed EPO-R, and one out of four showed an in vitro response to EPO. Although there was no significant correlation (r = 0.2522) between the amount of EPO-R and the in vitro response to EPO, all of the AML patients who showed in vitro response expressed EPO-R. Stem cell factor significantly enhanced both EPO-R expression and in vitro response to EPO. Interleukin-3 tended to increase in vitro response to EPO. CD phenotypes, the amount of granulocyte colony-stimulating factor (G-CSF) receptors and the amount of TPO receptors had no significant relationship with the amount of EPO-R. Patients with both EPO-R expression and in vitro response to EPO had shorter duration of complete remission than those without EPO-R (P = 0.0053). EPO-R was expressed in four (29%) out of 14 ALL, and none out of five ALL showed in vitro response to EPO.

Acute Disease↗

PubMed2000

Development of a TT virus DNA quantification system using real-time detection PCR.

Although TT virus (TTV) was isolated from a cryptogenic posttransfusion hepatitis patient, its pathogenic role remains unclear. It has been reported that the majority of the healthy population is infected with TTV. To elucidate the differences between TTV infection in patients with liver diseases and TTV infection in the healthy population, a quantification system was developed. TTV DNA was quantified by a real-time detection PCR (RTD-PCR) assay on an ABI Prism 7700 sequence detector. With this system, TTV DNA was quantified in 78 hepatitis C virus (HCV)-infected patients (63 with elevated serum alanine aminotransferase [ALT] levels and 15 with normal ALT levels) and in 70 voluntary blood donors (BDs). The quantification range was 2.08 to 7.35 log copies/ml. The intra-assay and interassay coefficients of variation were 0.37 to 6.33% and 0.60 to 7.07%, respectively. The mean serum TTV DNA levels in the HCV-infected patients with both elevated and normal ALT levels and BDs were 3.69 +/- 0.89, 3.45 +/- 0.76, and 3.45 +/- 0.67 log copies/ml, respectively. Comparison of the serum TTV DNA levels among the HCV-infected patients revealed that they were not related to the serum ALT and HCV core protein levels or to the histopathological score on liver biopsy. This study showed that (i) the RTD-PCR assay for the detection of TTV was accurate and had a high degree of sensitivity, (ii) the mean serum TTV DNA level was similar among HCV-infected patients, irrespective of their ALT level, and also among BDs, and (iii) a high serum TTV DNA level does not affect the serum ALT and HCV levels or liver damage in HCV-infected patients.

Blood Donors↗

PubMed2000

[Chemotherapy based on EBM in the field of hematological malignancies].

In the field of hematology/oncology, there are reasonable number of chemotherapy-related reports with level 1 evidences based on the analysis of the evidence based medicine (EBM). Following reasons may be pointed out; the first is that the history of chemotherapy has been initiated in the field of in hematology/oncology so it has more than 50 years' experience. The second is that leukemia and lymphoma are very chemosensitive diseases to compare with solid tumor, so the ultimate goal of their therapy is increase of the cure rate. The third is hematologists with high specialty only can manage such serious patients. Thus they have proposed plenty well-designed and well-organized clinical protocols and have performed some of them in this field. We have learned several recommended therapy of some hematological malignancies with level 1 evidences. It is not so easy, however, to treat all patients according to the best recommended therapy for Japanese patients, because of some limitations of using Japanese health insurance. This is very crucial problem for the patients. We should settle the issue from the scientific and social aspects as soon as possible.

Clinical Trials as Topic↗

PubMed2000

Therapy-related leukemia and myelodysplastic syndrome: a large-scale Japanese study of clinical and cytogenetic features as well as prognostic factors.

It is known that alkylating agents and topoisomerase II inhibitors can cause distinct forms of therapy-related leukemia and myelodysplastic syndrome (TRL/MDS). Although several reports have been made on each of these agents separately, no study has yet been conducted to evaluate the effect of these two types of agents in the same population. In a nationwide, large-scale population study, the clinical and cytogenetic features as well as the prognostic factors in 256 patients with TRL/MDS were assessed. Median age was 61 years, and the median period of latency from primary malignancies was 47.9 months. The latency period was significantly shorter in patients undergoing chemotherapy, especially that of topoisomerase II inhibitors, for primary cancer. The morphological diagnosis of TRL/MDS was acute myeloid leukemia in 59% and MDS in 41% of patients. Chromosome abnormalities that frequently involved chromosomes 5, 7 or 11 were documented in 77% of the 189 patients examined. MLL gene rearrangements were detected in 11 of 58 subjects and were correlated with a borderline significance (P = 0.072) with topoisomerase II inhibitor administration. Overall median survival was only 9.7 months. Survival was similar in cases with or without MLL gene rearrangement. Multivariate analysis identified chromosome 5 abnormalities, hypoproteinemia, poor therapy outcomes for primary cancer, C-reactive protein, and thrombocytopenia as being significantly poor prognostic factors (P < 0.05). This large-population study provided a comprehensive update of TRL/MDS status in Japan, identified significant prognostic factors, and enabled the clinical significance of MLL gene rearrangement to be assessed.

Adult↗

PubMed1999

Quantitative determination of a potent lipopolysaccharide antagonist, E5564, in rat and dog plasma by high-performance liquid chromatography with fluorescence detection.

The assay method was established for the quantification of a potent lipopolysaccharide (LPS) antagonist, E5564, in rat and dog plasma using HPLC. E5564 and the I.S. (an analogue of E5564) were extracted and derivatized with 9-Anthryldiazomethane (ADAM reagent) to be given fluorescence. LC-MS analysis indicated that single molecule of E5564 was coupled with two molecules of ADAM reagent at one on each of the phosphorus groups. After solid-phase extraction, ADAM derivatives of E5564 and the I.S. were separated on an ODS column using methanol/ethanol containing sodium acetate as a mobile phase at 1.2 ml/min (gradient elution), and detected by a fluorescence detector (excitation: 254 nm, emission: 415 nm). The intra-day and inter-day precision were less than 14.4%, and accuracy were within +/-13.0% in the concentration range of 30 to 20,000 ng/ml plasma in both species. E5564 was stable for at least 13 days in rat and dog plasma at -20 degrees C, and the processed sample was stable for up to 14 days at 4 degrees C. This validated method was successfully applied to the evaluation of the pharmacokinetics of E5564 in rats and dogs after single bolus intravenous doses.

Animals↗

PubMed1999

Workplace exposure to environmental tobacco smoke and high density lipoprotein cholesterol among nonsmokers.

There are few epidemiologic studies among adult nonsmokers on the effects of workplace environmental tobacco smoke on high density lipoprotein cholesterol (HDL-C). The authors investigated this relation, using data from health examinations conducted in 1995 on 3,062 Japanese nonsmokers in a total of 27 municipal offices with few smoking restrictions. Multiple regression analysis with adjustments for age, body mass index, alcohol drinking, and sports activities showed that in women, and in men lacking both alcohol consumption and sports activities characteristics, there were inverse linear relations between workplace smoking indices and HDL-C levels. Multivariate logistic regression showed that nonsmoking women in the upper two thirds of offices ranked by smoking intensity had an increased risk of low HDL-C levels (<45 mg), taking those in the lowest third of offices as reference (the medium third: odds ratio = 1.7; 95% confidence interval: 1.2, 2.5; the highest third: odds ratio = 1.6; 95% confidence interval: 1.1, 2.4). The results indicated that workplace environmental tobacco smoke exposure is associated with HDL-C among nonsmokers. However, the lack of data on home exposure limits causal inferences about the effects of workplace exposure.

Adult↗

PubMed1999

Mutation patterns for two flaviviruses: hepatitis C virus and GB virus C/hepatitis G virus.

We studied the mutation patterns of hepatitis C virus (HCV) and GB virus C/hepatitis G virus (HGV). Although the mutation patterns of the two viruses were similar to each other, they were quite different from that of HIV. In particular, the similarity of the patterns between HCV or HGV and human nuclear pseudogenes was statistically significant whereas there was no similarity between HIV and human nuclear pseudogenes. This finding suggests that the mutation patterns of HCV and HGV are similar to the patterns of spontaneous substitution mutations of human genes, implying that nucleotide analogues which are effective against HCV and HGV may have a side effect on the normal cells of humans.

Flaviviridae↗

PubMed1999

Prognostic implication of FLT3 and N-RAS gene mutations in acute myeloid leukemia.

Internal tandem duplication of the FLT3 gene and point mutations of the N-RAS gene are the most frequent somatic mutations causing aberrant signal-transduction in acute myeloid leukemia (AML). However, their prognostic importance is unclear. In this study, their prognostic significance was analyzed in 201 newly diagnosed patients with de novo AML except acute promyelocytic leukemia. Three patients had mutations in both genes, 43 had only the FLT3 gene mutation, 25 had only the N-RAS gene mutation, and 130 had neither. These mutations seemed to occur independently. Both mutations were related to high peripheral white blood cell counts, and the FLT3 gene mutation was infrequently observed in the French-American-British (FAB)-M2 type. AML cases with wild FLT3/mutant N-RAS had a lower complete remission (CR) rate than those with wild FLT3/wild N-RAS, whereas the presence of mutant FLT3 did not affect the CR rate. Univariate analysis showed that unfavorable prognostic factors for overall survival were age 60 years or older (P =.0002), cytogenetic data (P =.002), FAB types other than M2 (P =.002), leukocytosis over 100 +/- 10(9)/L (P =.003), and the FLT3 gene mutation (P =.004). However, the N-RAS gene mutation was only a marginal prognostic factor (P =.06). For the subjects under 60 years old, multivariate analysis showed that the FLT3 gene mutation was the strongest prognostic factor (P =.008) for overall survival. The FLT3 gene mutation, whose presence is detectable only by genomic polymerase chain reaction amplification and gel electrophoresis, might serve as an important molecular marker to predict the prognosis of patients with AML.

Acute Disease↗

PubMed1999

Phosphorylation and dephosphorylation of the B subunit of DNA polymerase alpha-primase complex in the early embryogenesis of Drosophila.

In the early embryos of Drosophila, the B subunit of the DNA polymerase alpha-primase complex was found to migrate more slowly during the first 13 mitotic cycles than that from cycle 14 using SDS-polyacrylamide gel electrophoresis. Lambda phosphatase treatment showed that the reduced migration was caused by phosphorylation of the B subunit. Detailed analysis using the partially purified B subunit indicated that most of the B subunit until cycle 13 was a phosphorylated form while the B subunit of cycle 14 was a dephosphorylated form.

Animals↗

PubMed1999

A new genotype of TT virus (TTV) infection among Colombian native Indians.

Serum TTV DNA was assayed in 140 native Indians and 40 members of the general population in Colombia to determine the prevalence of TT virus (TTV) infection among Colombian native Indians. Of the 140 native Indians, 23 (16.4%) were positive for TTV DNA, compared to 4 (10.0%) of 40 from the general population (P = not significant). The prevalence of TTV DNA among native Indians was much higher than that of HBsAg and anti-HCV. Comparison of subjects with and without TTV DNA revealed no significant differences in all characteristics between the two groups. A phylogenetic tree, using the open reading frame 1 sequence (222 bp), indicated that the virus could be classified into four different genotypes, including three previously reported ones. The results show that TTV infection is common in Colombian native Indians without liver disease and also indicate the existence of a novel genotype of TTV.

Adolescent↗

PubMed1999

Amino acid substitutions in NS5A region of GB virus C and response to interferon therapy.

GB virus C (GBV-C) is related to hepatitis C virus (HCV) and has a similar genomic structure. Some predictors for the efficacy of interferon (IFN) therapy on HCV have been reported: genotype, viral load, IFN dose, and the amino acid substitutions in the NS5A region, designated as the interferon sensitivity determining region (ISDR). To evaluate the correlation between the amino acid substitutions in the GBV-C NS5A region and the response to IFN therapy, single-strand conformation polymorphism (SSCP) analysis was performed in the 12 concomitantly GBV-C-and HCV-infected patients who received IFN therapy at three time points: before, end-point, and after the IFN therapy. The region in the GBV-C NS5A studied includes the amino acids that exhibit some homology to the ISDR and the various substitutions. By SSCP analysis, amplicons were separated into 1-4 bands, which indicated the existence of heterogeneity in each host. However, the deduced amino acid sequences in these bands exhibited no characteristic differences among these strains irrespective of response to IFN therapy. Of the 32 strains separated by SSCP, 7 strains were responders, and 25 were nonresponders. The mean amino acid substitution, compared with the consensus sequence of nonresponders, was 1.00+/-0.93 among responders, and 1.40+/-0.85 among non-responders (P= NS). No correlation between the amino acid sequence in the GBV-C NS5A region and response to IFN therapy was found, indicating that the GBV-C NS5A region dose not act as the ISDR.

Adult↗

PubMed1999

Association of cyclin D1 expression with factors correlated with tumor progression in human hepatocellular carcinoma.

The amplification and/or rearrangement of the cyclin D1 gene, a positive regulatory element of the G1 to S phase of the cell cycle, has been reported in various human tumors, suggesting an oncogenic role of this gene. In this study, we investigated the expression of cyclin D1 in the formalin-fixed and paraffin-embedded human hepatocellular carcinoma (HCC) tissues of 25 patients, using monoclonal antibody 5D4 raised against cyclin D1. Two distinct patterns of staining were observed in HCC cells, nuclear and cytoplasmic. The nuclear staining pattern of cyclin D1 was detected in the tissues of only 2 of the 25 HCC patients (8%) examined and no particular clinicopathological characteristics were found in these patients. In contrast, the cytoplasmic staining pattern, without nuclear staining, was detected in 8 of the 25 patients with HCC (32%). A significant correlation was found between the expression of cytoplasmic cyclin D1 and patients with tumor thrombus in the portal vein (Vp), as well as those with intrahepatic metastasis (IM). These results indicate that the cytoplasmic cyclin D1 expression appears to be related to the prognosis of HCC. The Ag nucleolar organizer regions (NORs) counts in cyclin D1-positive and -negative patients were not significantly different, suggesting that immunostaining for cyclin D1 has the potential to be a unique prognostic marker in human HCC. Simultaneous immunohistochemical study with p53 antibody in the same series of HCC revealed that 88% of the patients positive for cyclin D1 also expressed p53 and that in 91% of the patients negative for p53, cyclin D1 was not expressed. These results suggest that cyclin D1 is expressed later than the alteration of p53 in the progression of human HCC.

Adult↗

PubMed1999

High prevalence and phylogenetic analysis of TT-virus infection in Mongolia.

A novel DNA virus, TT-virus (TTV), was isolated from a post-transfusion hepatitis patient in Japan. The prevalence of TTV infection was investigated among patients with chronic liver disease and normal alanine aminotransferase (ALT) volunteers as controls in Mongolia. Polymerase chain reaction (PCR) was employed to detect TTV DNA using specific primers derived from open reading frame 1 (ORF1) of the TTV genome. Nucleotide sequences of samples positive for TTV DNA were determined. The sequences were analyzed by a molecular evolutionary method. Fifty (60.2%) hepatitis patients and 12 (42.9%) volunteers were positive for TTV DNA. The serum ALT levels did not differ significantly between patients with single TTV infection and without TTV, HBV and HCV infection. Similarly, the serum ALT levels did not differ significantly between controls with and without TTV infection. Dual infection of TTV with either HBV or HCV did not affect the ALT levels of hepatitis patients. The molecular evolutionary tree showed that TTV was a heterogeneous virus and all strains could be divided into three genotypes in Mongolia. A new genotype was identified that was distinct from those previously reported.

Adult↗

PubMed1999

Microsatellite instability associated with hepatocarcinogenesis.

BACKGROUND/AIMS: The biological and clinicopathological significance of microsatellite instability in hepatocellular carcinoma still remains to be determined. The aim of this study was to assess the role of microsatellite instability in hepatocarcinogenesis. METHODS: Genomic DNA extracted from 38 fresh samples of hepatocellular carcinoma was amplified by polymerase chain reaction using 29 fluorescence-labeled microsatellite markers and analyzed using a semi-automated laser scanning system. Associations between the incidence of replication error and the clinicopathological features of hepatocellular carcinoma were evaluated. Since reference DNA was extracted from corresponding fresh samples of non-cancerous liver tissue, the incidence of microsatellite instability in non-cancerous liver tissues was not assessed in this study. RESULTS: Four (11%) hepatocellular carcinomas had a replication error in one or two microsatellite markers; they were all poorly differentiated hepatocellular carcinomas. The incidence of replication error correlated significantly with the histological differentiation of the tumor (p<0.05) and with portal vein involvement (p<0.05). All four hepatocellular carcinomas with replication errors showed loss of heterozygosity in one or more of the 29 markers we examined. No replication errors were detected in six markers in the coding regions of the BAX, insulin-like growth factor II receptor, transforming growth factor-beta type II receptor, E2F-4, hMSH3 and hMSH6 genes. CONCLUSIONS: The results of this study indicate that: (1) microsatellite instability is a rare event during hepatocarcinogenesis and may be specifically associated with progression of hepatocellular carcinoma; and (2) frame-shift mutation in the above six genes is not a common mechanism involved in progression of this cancer.

Aged↗

PubMed1999

High prevalance of TT virus infection in Japanese patients with liver diseases and in blood donors.

BACKGROUND/AIMS: Although a novel DNA virus, TT virus (TTV), has been isolated from a patient with cryptogenic post-transfusion hepatitis, its pathogenic role remains unclear. To elucidate its prevalence and clinical impact in patients with liver diseases, the presence of TTV DNA was assessed in patients with liver diseases and blood donors (BDs) in Japan using two primer sets, one conventional and the other new and highly sensitive. METHODS: We studied 261 samples, 72 with chronic hepatitis associated hepatitis C virus (HCV-CH), 57 with hepatocellular carcinoma associated HCV (HCV-HCC), 12 with HCC without either HCV or hepatitis B virus (NBNC-HCC), and 120 of BDs. RESULTS: Using two primer sets, TTV DNA was detected in 68 (94.4%), 53 (93.0%), 12 (100%), and 98 (81.7%) HCV-CH, HCV-HCC, NBNC-HCC, and BDs, respectively. The prevalence was not significantly different between HCV-CH and HCV-HCC, or between HCV-HCC and NBNC-HCC. Comparison between patients with and without TTV revealed no significant differences in backgrounds or biochemical findings. Histopathological findings in patients with HCV-CH, and number, maximum diameter, and histological differentiation of HCC also did not demonstrate any relation to TTV infection. TTV strains can be divided into five groups using phylogenetic analysis, but no disease-specific group appears to exist. CONCLUSIONS: Our data suggest that: 1) TTV is very prevalent among patients with liver diseases and even among BDs in Japan, 2) TTV infection does not impact on liver damage with HCV infection, and 3) TTV infection also does not affect the development or progression of HCC.

Adult↗