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T Nakahata

Publications and source records attributed to T Nakahata.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Stem cell and self-renewal].

Stem cells are defined as cells with the ability for self-renewal and differentiation. Hematopoietic stem cells are well known, and their application is useful for the treatment of various kinds of diseases. Recently, neural stem cells have been identified even in the adult brain, which has up to now been considered to be a tissue with no regenerative capacity. In addition, it has emerged that tissue stem cells can differentiate into various kinds of cells beyond their original characteristics. Here, we discuss the self-renewal mechanisms of embryonic stem (ES) cells, hematopoietic stem cells and neural stem cells.

Animals↗
PubMed2001

[Hematopoietic stem cell transplantation with busulfanthiotepa-cyclophosphamide conditioning for pediatric patients with high-risk acute lymphoblastic leukemia].

Twelve children with high-risk acute lymphoblastic leukemia underwent stem cell transplantation (SCT) with a conditioning regimen consisting of busulfan, cyclophosphamide and thiotepa. Eight of them underwent SCT while in complete remission (CR) and the other 4 while not in CR. Three children underwent HLA-matched related bone marrow transplantation (BMT), 7 HLA-matched unrelated BMT, 1 HLA one-locus-mismatched unrelated cord blood cell transplantation, and 1 autologous peripheral blood stem cell transplantation. Grade II-IV acute GVHD was observed in 3 of the 11 allo-SCT cases, while chronic GVHD was seen in 3 of 9 evaluable cases. None of the 12 cases showed thrombotic microangiopathy, and veno-occlusive disease (VOD) was observed in 3. Nine of the patients are alive and disease-free 6-45 months after diagnosis. The event-free survival rate at 3 years was 72.2% for the 12 patients, including 8 of the 9 who received SCT during CR, and 2 of the 4 who did so while not in CR. The other 3 patients died: 2 of disease progression and 1 of VOD with pneumonia. All of those who died had undergone unrelated BMT.

Adolescent↗
PubMed2001

[Diagnosis and treatment of juvenile myelomonocytic leukemia(JMML)].

Juvenile myelomonocytic leukemia(JMML) is a rare myeloproliferative disorder of early childhood. It is usually characterized by peripheral monocytosis, increased level of HbF, and hypersensitivity of hematopoietic progenitors to granulocyte-macrophage colony-stimulating factor and hepatosplenomegaly. The pathogenesis of JMML has been associated with deregulated signal transduction and growth factor hypersensitivity. Allogeneic stem cell transplantation is the only curative approach but the roles of pretransplant chemotherapy, conditioning regimen and graft-versus-host disease are still unclear. Graft-versus-leukemia effect may play an essential role because withdrawal of immunosuppressive therapy and donor lymphocyte infusion was successful in the relapsed patients after transplantation.

Child↗
PubMed2000

Cloning and expression of human B cell-specific transcription factor BACH2 mapped to chromosome 6q15.

The transcription factor Bach2, a member of the BTB-basic region leucine zipper (bZip) factor family, binds to a 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive element and the related Maf-recognition element (MARE) by forming homodimers or heterodimers with Maf-related transcription factors. Bach2 regulates transcription by binding to these elements. To understand the function in hematopoiesis, we isolated a cDNA clone for human Bach2 (BACH2) encoding a protein of 841 amino acid residues with a deduced amino acid sequence having 89.5% identity to mouse homolog. Among human hematopoietic cell lines, BACH2 is expressed abundantly only in some B-lymphocytic cell lines. RT-PCR analysis of hematopoietic cells revealed that BACH2 mRNA is expressed in primary B-cells. Enforced expression of BACH2 in a human Burkitt cell line, RAJI that does not express endogenous BACH2, resulted in marked reduction of clonogenic activity, indicating that BACH2 possesses an inhibitory effect on cell proliferation. By fluorescent in situ hybridization, the BACH2 gene was localized to chromosome 6q15. Because deletion of the long arm of chromosome 6 (6q) is one of the commonest chromosomal alterations in human B-cell lymphoma, we examined for the loss of heterozygosity (LOH) of the BACH2 gene in human B-cell non-Hodgkin's lymphomas (NHL). Among 25 informative cases, five (20%) showed LOH. These results indicate that BACH2 plays important roles in regulation of B cell development.

Adult↗
PubMed2000

A method to identify cDNAs based on localization of green fluorescent protein fusion products.

We previously established a high-efficiency, retrovirus-mediated expression cloning method. Using this system, we now have developed an expression cloning method (FL-REX; fluorescence localization-based retrovirus-mediated expression cloning) in which cDNAs can be isolated based on the subcellular localization of their protein products. Complementary DNAs generated from mRNA using random hexamers were fused to the cDNA of green fluorescent protein (GFP) in the pMX retrovirus vector. The resulting cDNA-GFP fusion library was transfected into retrovirus-packaging cells, and the derived retroviruses were used to infect NIH 3T3 cells. Infected cells then were screened to identify cDNAs of interest through the subcellular localization of the GFP-fusion products. Using FL-REX, we have identified 25 cDNAs, most of which showed reasonable subcellular localization as GFP-fusion proteins, indicating that FL-REX is useful for identification of proteins that show specific intracellular localization.

3T3 Cells↗
PubMed2000

The IVS4 + 4 A to T mutation of the fanconi anemia gene FANCC is not associated with a severe phenotype in Japanese patients.

Fanconi anemia (FA) is an autosomal recessive disease characterized by congenital anomalies, aplastic anemia, and a susceptibility to leukemia. There are at least 8 complementation groups (A through H). Extensive analyses of the FA group C gene FANCC in Western countries revealed that 10% to 15% of FA patients have mutations of this gene. The most common mutation is IVS4 + 4 A to T (IVS4), a splice mutation in intron 4, which has been found only in patients of Ashkenazi Jewish ancestry. When we screened 29 Japanese patients (20 unrelated patients and 4 families) using polymerase chain reaction-single strand conformation polymorphism, we found 8 unrelated patients homozygous for IVS4. This is apparently the first non-Ashkenazi-Jewish population for whom this mutation has been detected. The Ashkenazi Jewish patients homozygous for IVS4 have a severe phenotype, in comparison with other FA patients. Our analyses of Japanese patients indicate no significant difference between IVS4 homozygotes and other patients with regard to severity of a clinical phenotype. Thus, ethnic background may have a significant effect on a clinical phenotype in FA patients carrying the same mutation. (Blood. 2000;95:1493-1498)

Adolescent↗
PubMed2000

SN-1, a novel leukemic cell line with t(11;16)(q23;p13): myeloid characteristics and resistance to retinoids and vitamin D3.

The MLL gene is fused with the cAMP-responsive element binding protein-binding protein (CBP) gene in t(11;16)(q23;p13), which has been reported to be associated with therapy-related acute leukemia. We established a novel myeloid cell line, SN-1, from a patient with T-cell acute lymphoblastic leukemia with t(11;16)(q23;p13) having in-frame MLL-CBP fusion transcripts. The majority of the SN-1 cells were positive for myeloperoxidase when examined using an electron microscope and expressed CD13, CD33, CD56, and HLA-DR antigens, but not CD7, CD10, CD19, CD34, or CD41 antigens, suggesting that these cells are of myeloid origin. SN-1 cells underwent functional and morphological differentiation when treated with actinomycin D or sodium butyrate, but not with all-trans-retinoic acid (ATRA) or 1alpha,25-dihydroxyvitamin D3 (VD3). Exposure of SN-1 cells to ATRA hardly affected cell growth and differentiation, whereas the growth of HL-60 and NB4 cells treated with ATRA was effectively inhibited, and differentiation into mature granulocytes was induced. SN-1 cells were relatively insensitive to VD3 with respect to inhibiting the cell growth and inducing the ability to reduce nitroblue tetrazolium, lysozyme activity, and morphological differentiation, although the expression of CD11b was slightly induced by VD3. These results suggest that the cell line was impaired in the signal transduction systems of ATRA and VD3. This cell line should be useful for the study of the role of CBP as a transcriptional regulator in leukemia differentiation and for the functional analysis of the MLL-CBP fusion gene, which will provide new insights into leukemogenesis caused by 11q23 translocations.

Amino Acid Sequence↗
PubMed2000

Peroxisome proliferator-activated receptors are expressed in mouse bone marrow-derived mast cells.

We examined the expression of peroxisome proliferator-activated receptors (PPARs) and the role of PPARs in cytokine production in mouse bone marrow-derived mast cells (mBMMCs). mBMMCs expressed PPARbeta strongly and gamma slightly, but not alpha. Activation of mBMMCs with antigen or calcium ionophore resulted in the increased expression of PPARgamma mRNA specifically. 15-Deoxy-Delta(12, 14)-prostaglandin J(2) (15d-PGJ(2)) and troglitazone, all PPARgamma ligands, attenuated the antigen-induced cytokine production by mBMMCs. Carbaprostacyclin, a PPARbeta ligand, also inhibited cytokine production, whereas PPARalpha ligands did not. These results suggest that PPARbeta and gamma might be included in the negative regulation of mast cell activation.

Animals↗
PubMed2000

Peroxisome proliferator-activated receptors are expressed in human cultured mast cells: a possible role of these receptors in negative regulation of mast cell activation.

We investigated the expression of peroxisome proliferator-activated receptors (PPAR) in human cultured mast cells (HCMC) by using the reverse transcription-polymerase chain reaction. HCMC expressed mRNA of PPARbeta, gamma1, and gamma2 constitutively, whereas PPARalpha was not detected. Though PPARgamma2 was expressed weakly, activation of HCMC with anti-IgE after IgE sensitization or with calcium ionophore plus phorbol ester resulted in increased expression of PPARgamma2 specifically. These stimuli did not influence the expression of PPARalpha and beta. In addition, provocation of HCMC with IgE or with IL-4 increased the mRNA level of PPARgamma2, and a synergistic effect was observed with the combination of IgE plus IL-4. To investigate a possible role of PPAR in mast cells, we examined the effects of PPAR agonists on cytokine production by HCMC. Prostaglandin (PG) D(2), Delta(12)-PGJ(2), 15deoxy-Delta(12, 14)-PGJ(2) (15d-PGJ(2)), and troglitazone, all of which are PPARgamma agonists, attenuated the production of granulocyte-macrophage colony-stimulating factor by anti-IgE-stimulated HCMC. A similar effect was observed with carbaprostacyclin, a PPARbeta agonist, but not with PPARalpha agonists. Anti-IgE-induced expression of cytokine mRNA, such as TNF-alpha, IL-5 and macrophage inflammatory protein-1alpha mRNA, was also reduced by the treatment with these PPARgamma agonists. Though only Delta(12)-PGJ(2) and 15d-PGJ(2) revealed an inhibitory effect on histamine release, leukotriene C(4) release from HCMC was suppressed by all tested PPARgamma agonists. These results indicate that HCMC express PPARbeta and gamma1/2, which might negatively regulate the activation of HCMC.

Antibodies, Anti-Idiotypic↗
PubMed2000

Molecular and clinical analysis of Japanese patients with 3-hydroxy-3-methylglutaryl CoA lyase (HL) deficiency.

Deficiency of mitochondrial 3-hydroxy-3-methylglutaryl CoA lyase (HL, EC4.1.3.4.) is an autosomal recessive genetic disorder characterized by acute episodes of vomiting, hypotonia, and lethargy in the neonatal period or in infancy. Except in Saudi Arabia, where HL deficiency is the most common organic acidemia, the disorder is quite rare with only 41 cases being reported in the English literature, and only five known cases among Japanese. In this study, we present the results of a molecular analysis of all five Japanese patients together with their clinical phenotypes. Five different mutations in the HL gene were identified: one large deletion, one nonsense mutation, one missense mutation, and two splice mutations. Except for G835A (E279K) with its relatively common occurrence among Japanese, these mutations were unique to each family. The results of expression studies with mutated HL cDNAs confirmed the pathogenicity of these mutations and supported the importance of previously identified functional domains of the HL molecule, i.e., the putative catalytic site or dimerization site. In addition, we identified an alternative splicing event that resulted in the skipping of exons 5 and 6. This alternatively spliced product did not show HL activity and was present in various tissues of normal subjects. Clinically, all patients presented with similar symptoms, except that the timing of the initial presentation varied considerably, from 1 day to 1 year 3 months. In general, patients with null-activity mutations presented earlier in life, whereas those with residual activities presented later.

Age of Onset↗
PubMed2000

Interstitial cystitis and ileus in pediatric-onset systemic lupus erythematosus.

A girl aged 11 years presented with autoimmune hemolytic anemia with thrombocytopenia, and subsequently developed severe abdominal pain, vomiting, and pollakiuria. X-ray findings of her abdomen demonstrated paralytic ileus with intestinal wall thickening. Intravenous pyelography revealed bilateral hydroureter with mild hydronephrosis and contracted bladder. Pathological examination of her bladder revealed interstitial cystitis, with evidence of focal deposition of IgG and C3 in a granular pattern on small blood vessel walls. She was diagnosed as having systemic lupus erythematosus (SLE) associated with paralytic ileus and chronic interstitial cystitis. Although initiation of high-dose prednisolone therapy resulted in a gradual improvement in clinical symptoms, reducing the dosage of prednisolone caused a relapse. To our knowledge, the combination of paralytic ileus and chronic interstitial cystitis is quite uncommon in pediatric-onset SLE.

Child↗
PubMed2000

Partial seizures in leukoencephalopathy with swelling and a discrepantly mild clinical course.

We report a patient with 'Leukoencephalopathy with swelling and a discrepantly mild clinical course', an entity of leukoencephalopathy recently clarified. Our patient presented with complex partial seizures in addition to characteristic radiological findings and clinical course. A review of the literature revealed that this new neurodegenerative disease complicates epilepsy in more than half of the patients, and that partial components in the seizure symptomatology are not infrequent.

Adolescent↗
PubMed2000

Extensive brain hemorrhage and embryonic lethality in a mouse null mutant of CREB-binding protein.

CREB-binding protein (CBP) is a transcriptional co-activator which is required by many transcription factors. Rubinstein-Taybi syndrome (RTS), which is an autosomal dominant syndrome characterized by abnormal pattern formation, is associated with mutations in the human CBP gene. Various abnormalities occur at high frequency in the skeletal system of heterozygous Cbp-deficient mice, but some features of RTS such as cardiac anomalies do not, suggesting that some symptoms of RTS are caused by a dominant-negative mechanism. Here we report the characterization of homozygous Cbp-deficient mice. Homozygous mutants died around E10.5-E12.5, apparently as a result of massive hemorrhage caused by defective blood vessel formation in the central nervous system, and exhibited apparent developmental retardation as well as delays in both primitive and definitive hematopoiesis. Cbp-deficient embryos exhibited defective neural tube closure which was similar to those observed in twist-deficient embryos. However, a decrease in the level of twist expression was not observed in Cbp-deficient embryos. Anomalous heart formation, a feature of RTS patients and mice mutated in the CBP-related molecule, p300, was not observed in Cbp-deficient embryos. Since both Cbp and p300 are ubiquitously expressed in embryonic tissues including the developing heart, these results suggest that cardiac anomalies observed in RTS patients may be caused by a dominant negative effect of mutant CBP.

Animals↗
PubMed2000

Improvement in bronchiolitis obliterans organizing pneumonia in a child after allogeneic bone marrow transplantation by a combination of oral prednisolone and low dose erythromycin.

We report a 13-year-old boy who developed dyspnea at rest 1 year after the occurrence of cGVHD following an allogeneic bone marrow transplant (BMT). Pulmonary function data, imaging studies, lung biopsy, and bronchoalveolar lavage were consistent with the diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP). Although reports suggest that oral methylprednisolone or methylprednisolone pulse therapies improve BOOP after BMT, we treated our patient with a combination of oral prednisolone (1 mg/kg) and low dose erythromycin (10 mg/kg) to avoid the side-effects of high-dose steroids. With this therapy, our patient showed clinical and radiological improvements within 1 week. The steroids were tapered off 12 months later and erythromycin was given for 14 months. We conclude that therapy consisting of a combination of oral prednisolone and low-dose erythromycin for BOOP after BMT may minimize the dose and duration of steroid use.

Administration, Oral↗
PubMed2000

Natural killer cell depletion by anti-asialo GM1 antiserum treatment enhances human hematopoietic stem cell engraftment in NOD/Shi-scid mice.

The scid mutation was backcrossed on to the NOD/Shi mouse background, resulting in the development of NOD/Shi-scid mice, which showed lack of mature lymphocytes, macrophage dysfunction and absence of circulating complement, but were not as impaired in natural killer (NK) cell activity as NOD/LtSz-scid mice. We then examined the effect of recipient NK cell depletion by anti-asialo GM1 antiserum on the repopulation of human cord blood (CB) hematopoietic stem cells (HSC) in NOD/Shi-scid mice to clarify the role of recipient NK cells in human HSC engraftment. The anti-asialo GM1 antiserum treatment significantly enhanced the engraftment of CB CD34+ cells, but did not affect the differentiation of the engrafted HSC into each hematopoietic lineage. The NK cell depletion was effective at early stages of the engraftment, but not 3 weeks after the transplantation. The anti-asialo GM1 antiserum treatment did not improve the engraftment by human HSC in scid mice which lack mature lymphocytes, but show neither macrophage dysfunction nor a reduction in circulating complement, indicating that macrophages and/or complement also have roles in HSC graft rejection. The present study indicates that the preconditioning targeting of recipient NK cells in addition to T cell suppression and myeloablation might prevent HSC graft failure, and that NOD/Shi-scid mice treated with anti-asialo GM1 antiserum could provide a useful tool for evaluating the repopulating ability of transplantable human HSC.

Animals↗
PubMed2000

Exclusive expression of G-CSF receptor on myeloid progenitors in bone marrow CD34+ cells.

Although granulocyte colony-stimulating factor (G-CSF) has been reported to act on cells of neutrophilic lineage, the administration of G-CSF to induce the mobilization of various haematopoietic progenitors into the circulation. We analysed the expression of receptors for G-CSF (G-CSFR) on human bone marrow and G-CSF-mobilized peripheral blood CD34+ cells, and examined the proliferation and differentiation capabilities of sorted CD34+G-CSFR+ and CD34+G-CSFR- cells using methylcellulose clonal culture. Flow cytometric analysis showed that G-CSFR was expressed on 14.9 +/- 4.9% of bone marrow CD34+ cells, most of which were included in CD34+CD33+ and CD34+CD38+ cell fractions. In clonal cultures, CD34+G-CSFR+ cells produced only myeloid colonies, whereas CD34+G-CSFR- cells produced erythroid bursts, megakaryocyte and multilineage colonies. When incubated with the cytokine cocktail for 5 d, CD34+G-CSFR- cells generated CD34+G-CSFR+ myeloid progenitors. In G-CSF-mobilized peripheral blood, CD34+ cells contained 10.8 +/- 5.8% of G-CSFR+ cells, most of which were also myeloid progenitors, although CD34+G-CSFR- cells contained a substantial number of myeloid progenitors. These results indicated that the expression of G-CSFR on CD34+ cells is restricted to myeloid progenitors, suggesting that the specific activity of G-CSF on myelopoiesis depends on the exclusive expression of its receptor on myeloid progenitors, and that the mobilization of various haematopoietic progenitors is not a direct effect of G-CSF in humans.

Adult↗
PubMed2000

Cytokine requirement for the development of T-lymphoid lineage potential in clonal lymphohaematopoietic progenitors in vitro.

The early process of T-cell development prior to thymic colonization has been poorly investigated because of the lack of a sensitive assay. We have developed a two-step in vitro culture system by combining a clonal culture with a fetal thymus organ culture (FTOC) and analysed the early development of T cells from lymphohaematopoietic progenitors. Cells of immature colonies derived from bone marrow cells of 5-fluorouracil (5FU)-treated mice using various combinations of early acting cytokines were transferred into a FTOC. All the combinations of stem cell factor (SCF), interleukin (IL)-3 and IL-6 capable of inducing colony formation supported T-cell generation. IL-11 and the Flt3 ligand possessed T-lineage promotional effects similar to IL-6 and SCF respectively. However, there were some quantitative differences in the final T-cell yield among cytokine combinations. Thus, the commitment towards T lineage in lymphohaematopoietic progenitors may be an event determined intrinsically rather than induced by specific stimuli, but there may be a hierarchy between the activity of cytokines in further development. Furthermore, we examined the T-lineage potential of individual colonies derived from Lin(-)c-Kit(+)Sca-1(+) cells clone-sorted from post-5FU marrow cells. No colonies that contained only myelocytic progenitors showed T-lineage potential, but 23.3% of colonies with a haematopoietic multipotentiality did. Therefore, the divergence of the T lineage from other lineages such as myeloid potential may occur at an early stage of the hierarchy of haematopoiesis. The proposed method should prove valuable for exploring the molecular and cellular changes that occur during early T-cell development before thymic colonization.

Animals↗