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Biomedical subjects

M Eguchi

Publications and source records attributed to M Eguchi.

At least 73 records · Page 4Linked to original sources
PubMed1999

WASP is involved in proliferation and differentiation of human haemopoietic progenitors in vitro.

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disorder characterized by thrombocytopenia, immunodeficiency and eczema. X-linked thrombocytopenia (XLT) is a mild form of WAS with isolated thrombocytopenia. Both phenotypes are caused by mutation of the Wiskott-Aldrich syndrome protein (WASP) gene. In this study we investigated the role of WASP in the differentiation of CD34-positive (CD34+) cells isolated from the bone marrow of patients with WAS (n = 5) or with XLT (n = 4). Megakaryocyte colony formation was significantly decreased in patients with WAS when compared with normal controls. The formation of granulocyte-macrophage colonies and erythroid bursts were also decreased in WAS patinets. In contrast, in XLT patients, formation of all these colonies was normal. However, in vitro proplatelet formation of megakaryocytes induced by thrombopoietin was markedly decreased in both XLT and WAS. Electron microscopic examination revealed that megakaryocytes obtained from WAS or XLT patients grown in vitro had abnormal morphologic features, which seemed to be caused by defective actin cytoskeletal organization, including labyrinth-like structures of the demarcation membrane system and deviated distribution of the alpha-granules and demarcation membrane system. These observations indicate that WASP is involved in the proliferation and differentiation of CD34+ haemopoietic progenitor cells probably by its participation in signal transduction and in the regulation of the cytoskeleton.

Blood Platelets↗
PubMed1999

Protein expression of cell cycle regulator, p27Kip1, correlates with histopathological grade of non-Hodgkin's lymphoma.

The protein p27Kip1 is one of the cyclin-dependent kinase inhibitors that are known to play important roles in the regulation of cell-cycle progression. Low levels of p27 expression in malignant cells are associated with poor prognosis in patients with breast, lung, colorectal and gastric cancers. To determine the relation of cyclin-dependent kinase inhibitors to histopathological grades of B-cell non-Hodgkin's lymphomas, the expression of p27, cyclin D1 and cyclin E in lymph node tissues was investigated in 56 patients with B-cell non-Hodgkin's lymphomas by western blotting and immunohistochemical techniques. High levels of p27 expression were observed in most lymph node tissue samples (93%) obtained from patients with low grade B-cell non-Hodgkin's lymphomas, while expression was low in lymph node tissue taken from all patients with intermediate and high grade B-cell non-Hodgkin's lymphomas. The difference in p27 expression in lymphoma tissues was significant among the different histopathological grades of B-cell non-Hodgkin's lymphomas (P<0.01). The analysis of the survival time of patients showed that the reduction of p27 expression correlated with poor prognosis. Cyclin D1, showed a high level of expression in mantle cell lymphomas and high grade B-cell non-Hodgkin's lymphomas. Cyclin E showed limited expression in 18 of 31 lymphoma tissues. Both cyclin D1 and E protein expression were not significantly different among the grades of B-cell non-Hodgkin's lymphomas. These results demonstrate that the level of p27 expression in lymphoma tissue is an important parameter in the classification of B-cell non-Hodgkin's lymphomas and in the prediction of prognosis.

Blotting, Western↗
PubMed1999

Soluble methane monooxygenase gene clusters from trichloroethylene-degrading Methylomonas sp. strains and detection of methanotrophs during in situ bioremediation.

The soluble MMO (sMMO) gene clusters from group I methanotrophs were characterized. An 8.1-kb KpnI fragment from Methylomonas sp. strain KSWIII and a 7.5-kb SalI fragment from Methylomonas sp. strain KSPIII which contained the sMMO gene clusters were cloned and sequenced. The sequences of these two fragments were almost identical. The sMMO gene clusters in the fragment consisted of six open reading frames which were 52 to 79% similar to the corresponding genes of previously described sMMO gene clusters of the group II and group X methanotrophs. The phylogenetic analysis of the predicted amino acid sequences of sMMO demonstrated that the sMMOs from these strains were closer to that from M. capsulatus Bath in the group X methanotrophs than to those from Methylosinus trichosporium OB3b and Methylocystis sp. strain M in the group II methanotrophs. Based on the sequence data of sMMO genes of our strains and other methanotrophs, we designed a new PCR primer to amplify sMMO gene fragments of all the known methanotrophs harboring the mmoX gene. The primer set was successfully used for detecting methanotrophs in the groundwater of trichloroethylene-contaminated sites during in situ-biostimulation treatments.

Amino Acid Sequence↗
PubMed1999

Development of a PCR test for rapid diagnosis of contagious equine metritis.

In order to establish a rapid diagnostic method for contagious equine metritis (CEM), we developed and evaluated a polymerase chain reaction (PCR) test. Species-specific PCR primer sets were derived from the DNA sequence of a cloned DNA fragment of Taylorella equigenitalis that did not hybridize with the genome of a taxomonically related species, Oligella urethralis. Single step PCR with primer set P1-N2 and two-step semi-nested PCR with primer sets P1-N2 and P2-N2 detected as low as 100 and 10 CFU of the bacteria, respectively. Single-step PCR detected T. equigenitalis from genital swabs of experimentally infected mares with sensitivity comparable to that of bacterial isolation. Furthermore, two-step PCR was more sensitive than the culture method. Upon examination of field samples, 12 out of 3,123 samples were positive by single-step PCR while only 2 were positive by bacterial culture. The 12 PCR-positive samples originated from 5 mares, of which 3 animals were considered to be carriers based on previous bacteriologic and serologic diagnoses for CEM. The PCR test described in this study would provide a specific and highly sensitive tool for the rapid diagnosis of CEM.

Animals↗
PubMed1999

Neurenteric cyst of the craniocervical junction--case report.

A 60-year-old female presented with occipital headache and limitation of neck movement. Neurological examination showed weakness of the right sternocleidomastoid muscle. Magnetic resonance imaging revealed a cystic lesion at the craniocervical junction and posterior compression of the brain stem. The lesion was totally removed through the transcondylar approach. The histological diagnosis was neurenteric cyst. The transcondylar approach provides a direct operative view of the clivus and anterior craniovertebral junction.

Craniotomy↗
PubMed1999

Instability of chromosome 7 in colony forming cells of patients with aplastic anemia.

Monosomy 7 in isolated bone marrow mononuclear cells and colony forming cells from patients with aplastic anemia who later developed myelodysplastic syndrome/leukemia with monosomy 7 were examined by fluorescence in situ hybridization. Colonies derived from bone marrow mononuclear cells of the aplastic anemia patients consisted of a mixture of cells of normal karyotype and monosomy 7, ranging from 0 to 97.2%. This result suggests that colony forming cells initially had a normal karyotype but then lost chromosome 7 during growth in the semisolid culture. This finding suggests the genetically unstable condition of chromosome 7 in colony forming cells in aplastic anemia patients. This chromosome instability of colony forming cells may lead to malignant transformation.

Anemia, Aplastic↗
PubMed1998

Defective control of apoptosis, radiosensitivity, and spindle checkpoint in ataxia telangiectasia.

We examined the regulation of apoptosis, radiosensitivity, and spindle checkpoint in response to DNA-damaging agents in ataxia telangiectasia (AT)-derived lymphoblastoid cell lines (AT-LCLs), which lack AT mutated (ATM) protein expression. In addition to the previous findings that AT-LCLs are defective in regulation of cell cycle at the G1, S, and G2-M checkpoints in response to X-ray irradiation (X-IR) and are highly sensitive to X-IR (J. Biol. Chem., 271: 20486-20493, 1996), we showed for the first time that AT-LCLs were defective in X-IR-associated spindle checkpoint control. The cells were also resistant to early apoptosis as much as LCLs derived from patients with Li-Fraumeni syndrome (LFS-LCLs). Terminal deoxynucleotidyl transferase-mediated nick end labeling assay of LCLs, however, demonstrated a significant increase in apoptotic cells among AT-LCLs cultured over a longer period after X-IR. These findings were in contrast to those of LFS-LCL, which showed very little increase in terminal deoxynucleotidyl transferase-mediated nick end labeling-positive population, even in cells with hyperploidy. Thus, although early apoptosis and cell cycle controls in response to DNA damage are disrupted in both ATM and p53 mutations, cells from AT patients are much more susceptible to late-onset apoptosis than those of LFS. These differences may depend on the level of accumulation of DNA damage and/or threshold that triggers late-onset cell death in ATM or p53 mutations. Our findings allow a better understanding of the role of ATM in p53-dependent and independent signal transduction pathways in response to DNA damaging agents.

Apoptosis↗
PubMed1998

Interleukin-4 promotes the development of tryptase and chymase double-positive human mast cells accompanied by cell maturation.

Human cultured mast cells (HCMCs) grown from cord blood mononuclear cells in the presence of stem cell factor (SCF) and interleukin-6 (IL-6) expressed tryptase but no or low chymase in their cytoplasm. The addition of IL-4 to these cells strikingly increased chymase expression. Consequently, the activity of chymase was significantly higher in IL-4-treated mast cells than that in IL-4-nontreated mast cells, whereas the activity of tryptase and histamine content were comparable in both cells. Electron microscopic immunocytochemistry also showed that secretary granules containing chymase increased in IL-4-treated mast cells. Interestingly, the IL-4-induced increase of chymase expression in HCMCs was accompanied by morphological maturation of the cells. Cytoplasmic projections were few in IL-4-nontreated HCMCs, and a small number of secretary granules were observed, most of which were empty or partially filled with discrete scrolls with rough particles showing immaturity. In contrast, IL-4-treated HCMCs had extremely abundant cytoplasmic projections and had many secretary granules filled with electron-dense crystal materials. Taken together, immature HCMCs grown only with SCF and IL-6 expressed tryptase with no or a low amount of chymase, and addition of IL-4 promoted cell maturation together with the expression of both tryptase and a high amount of chymase. Our findings will raise a possibility of a linear pathway of human mast cell development from tryptase single positive mast cells into tryptase and chymase double positive mast cells as the cells mature and will suggest that this maturation process is promoted by IL-4.

Cell Differentiation↗
PubMed1998

Analysis of C-KIT, TIE and HTK expression on leukemic cells using flow cytometry: a preliminary report.

C-KIT, TIE and HKT expression on leukemic cells from patients were simultaneously analyzed using flow cytometry. Consistent with previous reports, leukemic cells from most patients with de novo acute myeloid leukemia (AML) were C-KIT-positive (28/35), while those from patients with B-lineage acute lymphoid leukemia (B-ALL) were C-KIT-negative (0/9). In the B-ALL patients, leukemic cells trom seven patients had one or more myeloid antigen such as CD13, CD15 and CD33. In contrast to C-KIT expression, leukemic cells from only one patient with acute monocytic leukemia were TIE-positive. Similarly, leukemic cells from only two patients (one, B-ALL with t(4;11)(q21;q23) and one, essential thrombocythemia in myeloblastic transformation (ET-MBT)) were HTK-positive. These results suggest that among the three receptor tyrosine kinases, C-KIT is the most useful marker for identifying AML.

Antibodies, Monoclonal↗
PubMed1998

Establishment of a novel cell line (TS-2) of pre-B acute lymphoblastic leukemia with a t(1;19) not involving the E2A gene.

The t(1;19)(q23;p13) translocation involving the E2A gene on chromosome 19p13.3 is a nonrandom translocation that is often seen in childhood pre-B-cell acute lymphoblastic leukemia (ALL). However, recent studies have demonstrated the presence of immunophenotypic and molecular heterogeneity among patients with the cytogenetically identical chromosome translocation. Here we report a novel pre-B ALL cell line, TS-2, with t(1;19) translocation not involving the E2A gene. The breakpoint of t(1;19) in TS-2 was demonstrated to be at 19p13.3, a region indistinguishable from the locus of the E2A gene, by cytogenetic study and fluorescence in situ hybridization. However, rearrangement of the E2A gene was not detected in TS-2 by Southern blot analysis. Moreover, the expressions of PBX1 or E2A/PBX1 fusion genes were not detected by an extensive study with Northern blot analysis and reverse transcription-polymerase chain reaction. These findings suggest that TS-2 may have a genetic abnormality involving uncharacterized gene(s) at 19p13.3 distinct from the E2A gene and, therefore, may be useful for investigating the heterogeneity of molecular pathogenesis in leukemias with t(1;19)(q23;p13) translocation.

Adenovirus E2 Proteins↗
PubMed1998

High frequency of fusion transcripts of exon 11 and exon 4/5 in AF-4 gene is observed in cord blood, as well as leukemic cells from infant leukemia patients with t(4;11)(q21;q23).

The MLL gene located on chromosome 11q23 and its translocation to the AF-4 gene located on chromosome 4q21 play a pivotal role in leukemogenesis in infancy. Studies of identical leukemic twins have provided evidence of the MLL rearrangement as a fetal event during pregnancy. We analyzed the presence and frequency of the MLL/AF-4 rearrangement in normal cord blood. Although no chimeric mRNA of MLL or AF-4 was detected in 65 cord blood samples, in-frame fusion transcripts of exon 11 and exon 4 or 5 of the AF-4 gene were detected in three of the samples by a nested polymerase chain reaction. When primers of exon 11 and exon 5 of the AF-4 gene were used, two forms of fusion transcripts (AF-4 exon 11/4 or exon 11/5) were detected in 20 of the 65 cord blood samples (31%) and also four of six leukemic cell samples with t(4;11) (67%), whereas such transcripts were not observed in any of 21 peripheral blood samples nor in fetal fibroblasts. These findings suggest that the in-frame fusion of exon 11 and exon 4 or 5 of the AF-4 gene frequently occurs in hematopoietic cells during the intrauterine period, even in a healthy fetus. Although it is unknown whether the proteins of the AF-4 fusion transcripts have some functions, the instability of the AF-4 gene may be associated with the leukemogenesis of infant leukemia.

Chromosomes, Human, Pair 11↗
PubMed1998

Establishment of a novel human myeloid leukaemia cell line (FKH-1) with t(6;9)(p23;q34) and the expression of dek-can chimaeric transcript.

Translocation t(6:9)(p23;q34), resulting in a dek-can gene fusion, is a recurrent chromosomal abnormality mainly associated with specific subtypes of acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS). Patients with this type of chromosomal change are usually young and their prognosis is poor. The role of fusion protein generated from dek-can chimaeric transcript on the leukaemogenesis oft(6;9) AML or MDS is as yet unknown. We have established the first permanent cell line (FKH-1) with t(6;9). derived from the peripheral blood of a patient with t(6:9) AML transformed from Philadelphia chromosome (Ph1)-negative chronic myelocytic leukaemia (CML). The FKH-1 expressed myelomonocytic markers and dek-can chimaeric transcript. In the presence of 10 ng/ml recombinant human granulocyte colony-stimulating factor (G-CSF), the cells doubled every 54 h and showed multilineage myeloid differentiation, resulting in heterogenous morphologies such as macrophages, basophils, eosinophils and neutrophils. Thus, this cell line may be derived from a pluripotent myeloid stem cell and should be a useful tool for biomolecular studies on the pathogenesis of t(6;9) myeloid malignancies which have rarely been investigated because of the lack of continuously proliferating cells.

Cell Division↗
PubMed1998

Fluorescence in situ hybridization analysis of 12;21 translocation in Japanese childhood acute lymphoblastic leukemia.

Fluorescence in situ hybridization (FISH) analysis was applied to detect t(12;21) using two yeast artificial chromosome probes and cosmid probes covering the TEL(ETV6) and the AML1 gene to clarify the incidence of abnormality of t(12;21) in Japanese childhood acute lymphoblastic leukemia (ALL). We detected seven TEL/AML1 fusion positive patients (9.5%), all of whom were diagnosed as B-lineage ALL, among 74 childhood ALL. On the other hand, no TEL/AML1 fusion positive patients were found among 37 adult ALL. The incidence among Japanese seemed to be lower than that among other nations. Of the seven patients with the TEL/AML1 fusion, five exhibited normal karyotype, one was t(8;12)(q11;p13), i(21q) and the remaining one exhibited a near-triploid karyotype in conventional G-banding. The FISH method clearly demonstrated that all patients with the TEL/AML1 fusion had subpopulations of leukemic cells with deletion of the normal TEL allele, which is significant for understanding the progression of leukemia with t(12;21).

Blotting, Southern↗
PubMed1998

Recurrent hepatosplenomegaly and peripheral blood cytopenia, persistent Epstein-Barr virus infection and central nervous system manifestation in a patient with lymphadenopathy and low serum uric acid.

We describe a 27-month-old boy who was first admitted to our hospital on 7 January 1995 with nasal bleeding. From 6 months of age he has had lymphadenopathy, low levels of serum uric acid, increased levels of serum lactate dehydrogenase and hyper gamma-globulinemia. From the age of 18 months he has had persistent Epstein-Barr virus (EBV) infection (target cells; B cells), recurrent episodes of thrombocytopenia, anemia and hepatosplenomegaly. Dysmobility of the left leg and arm from a central nervous system complication during a relapse with pancytopenia on March 1995, was also observed. Relapses of thrombocytopenia with increases of platelet-associated immunoglobulin G and hepatosplenomegaly have been observed approximately every 2 months, and two relapses of pancytopenia were accompanied with weak positivity of Coombs test and low level of haptoglobin. These recurrent episodes were improved with prednisolone. However, now in June 1997 we have not been able to diagnose what underlies the above clinical symptoms, except that the patient has a persistent EBV infection.

Central Nervous System Diseases↗
PubMed1998

[Therapy-related MDS/leukemia carrying dup(11) (q21q23) with MLL gene tandem duplication].

A 42-year-old woman had been given a diagnosis of malignant lymphoma, follicular, small cleaved cell. She had undergone chemotherapy including etoposide (1,500 mg/total) and was in her second complete remission. Four years and 4 months later, refractory anemia with excess of blasts (RAEB) with dup(11) (q21q23) x 2 developed in the patient and progressed to acute myeloid leukemia (AML-M5b). Despite regression of the AML to RAEB, a clone with the additional abnormality of del(20) (q11q13.1) appeared and transformed the RAEB into AML-M6. Rearrangement of the MLL gene was observed, and FISH analysis demonstrated that the signal sequences from the gene's 5' and 3'-terminal regions had detached. RT-PCR techniques detected a tandem duplication of MLL gene exons 2 through 8. This was considered to be one of the mechanisms behind the formation of the 11q23 abnormality observed in this patient.

Adult↗
PubMed1998

GATA-1 and erythropoietin receptor genes are highly expressed in erythroleukemia.

We examined expression of the erythroid-associated genes GATA-1 and erythropoietin receptor (EPOR) in primary leukemia using the reverse transcriptase-polymerase chain reaction (RT-PCR). GATA-1 and EPOR mRNAs were detectable in all cases of erythroleukemia (French-American-British classification: M6) or early erythroblastic leukemia. In all other leukemia cases, including M2 through M5, stem cell leukemia, and adult T-cell leukemia, these gene transcripts were undetectable. GATA-2 was detectable in all the cases of primary leukemias examined in this study, except one case of M5. In one case, the phenotype switched from myeloid (M2) to erythroid (M6) and then back to myeloid. Northern blotting and RT-PCR revealed that GATA-1 and EPOR mRNAs were significantly upregulated at the M6 stage compared with the M2 stage. GATA-1 may be involved in the expression of an erythroid phenotype in acute leukemia. We generated HL-60 transfectants exogenously expressing GATA-1. The majority of HL-60 cells expressing GATA-1 lacked azurophilic granules, and electron microscopic analysis revealed that myeloperoxidase activity was negative. Platelet peroxidase activity, which was detectable in both megakaryoblasts and erythroid progenitors, was positive. However, EPOR and glycophorin A mRNAs were undetectable by RT-PCR. These findings suggest that besides GATA-1, a third factor may be required for the expression of mature erythroid phenotypes. In addition, our results indicate that GATA-1 is involved in inactivation of myeloperoxidase and activation of the platelet peroxidase.

Cell Size↗