T Shimamoto

Tokyo Medical University, Edo, Tōkyō, Japan

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Publications (62)241.02 Total impact

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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2010; 32(31).
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    ABSTRACT: We describe a patient with hepatosplenic 33 T-cell lymphoma who showed pancytopenia and myelodysplasia. A 35-year-old man was admitted with fever, pancytopenia, and hepatosplenomegaly but with no lymphadenopathy. We also found trilineage myelodysplasia in the bone marrow on his first admission. The patient had high fever and anemia but no evidence of infection and was tentatively treated with prednisolone. This treatment resulted in a transient improvement of the cytopenia and a reduction of spleen size. However, 10 months after the first manifestation, progression of the splenomegaly and fever became apparent, and a splenectomy was performed. The pathologic findings for the spleen showed diffuse and disseminated infiltration of medium- to large-sized T-lymphocytes in the splenic red pulp. These cells were immunohistochemically positive for CD3, CD5, CD7, CD8, CD16, CD56,T-cell receptor 33 (TCR33),T-cell intracellular antigen 1, and granzyme B but were negative for CD4, CD30, CD57, and TCR33. These data suggested a diagnosis of hepatosplenic 33 T-cell lymphoma. A Southern blot analysis revealed gene rearrangement of the TCR 3-chain gene but not the immunoglobulin heavy chain gene in the spleen cells. An in situ hybridization analysis for the Epstein-Barr virus revealed negative results. The patient received 8 courses of combination chemotherapy and achieved a partial remission; however, the dysplastic features of the marrow cells persisted after the partial remission was obtained. Additional treatment with allogeneic bone marrow transplantation resulted in a transient complete remission; however, the patient relapsed 11 months later. Because he had experienced no lymphadenopathy and showed dysplastic features in the bone marrow, the diagnosis was highly dependent on the pathologic findings for the resected spleen.
    International Journal of Hematology 09/2005; 82(2):143-7. · 1.68 Impact Factor
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    ABSTRACT: This study detected clonal T cells in patients with acquired pure red-cell aplasia (PRCA) by Southern blotting and polymerase chain reaction (PCR). Twenty-nine adult patients with acquired PRCA were enrolled in this study. Seventeen patients had primary acquired PRCA, while 12 patients had the secondary form. Twenty-two of 29 (76%) patients demonstrated TCR rearrangement by at least one method. We divided the patients into three groups depending on T-cell clonality. The CD4/8 ratio of patients who were positive on Southern blotting was significantly lower than that of other groups. Except for the CD4/8 ratio, other laboratory findings did not significantly differ among the three groups. The CD4/8 ratio should be a useful surrogate marker to detect T-cell clonality.
    American Journal of Hematology 09/2005; 79(4):332-3. · 4.00 Impact Factor
  • Leukemia and Lymphoma 06/2005; 46(5):789-91. · 2.61 Impact Factor
  • Takashi Shimamoto, Junko H Ohyashiki, Kazuma Ohyashiki
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    ABSTRACT: Hypermethylation of CpG islands is a common mechanism by which tumor suppressor genes are inactivated. The tumor suppressor gene p15(INK4b) is important component of cell cycles, whereas E-cadherin gene is often termed a metastasis suppressor gene. We have studied the feasibility of detecting tumor-associated aberrant p15(INK4b) and E-cadherin methylation in acute myeloid leukemia (AML) using methylation-specific PCR. Aberrant methylation of p15(INK4b) was detected in 31 of 61 (51%) AML patients. On the other hand, E-cadherin hypermethylation was detected in 36 of 61 (56%) AML patients. We have examined the methylation pattern of these genes and the prognosis in AML patients using a log-rank test. Methylation of p15(INK4b) gene significantly correlated with prognosis (p=0.0012), and methylation of E-cadherin gene more significantly correlated with prognosis (p=0.0004). When both were methylated, there was even more significant unfavorable prognosis compared to either of the methylated genes (p<0.0001). We interpret these data to mean that dysfunction of the cell cycle and/or the cell-cell adhesion molecule plays a role in the pathogenesis of acute myeloid leukemia and that analysis of the methylation of p15(INK4b) and E-cadherin genes can provide clinically important evidence on which to base treatment.
    Leukemia Research 06/2005; 29(6):653-9. · 2.76 Impact Factor
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    ABSTRACT: A 60-year-old male was referred to our hospital because of cervical lymphadenopathy and a left hilar abnormal shadow seen on chest X-ray in May 1999. The pathological findings of the cervical lymph nodes revealed that the patient had a malignant lymphoma, of the diffuse large B cell type, at clinical stage IIIB. Immunohistochemistry demonstrated that the lymphoma cells were positive for CD11a, CD19, CD20, CD23, CD25, CD45, IgM, IgD and lambda, but negative for CD5. Although a complete remission was obtained after 8 courses of CHOP therapy, the patient relapsed 32 months later. Two courses of a half dose of CHASE therapy consisting of CPM, ara-C, VP-16 and dexamethasone, followed by rituximab (600 mg/week x4) resulted in a transient re-induction of complete remission. However, multiple cutaneous tumors became apparent just 10 days after the last rituximab therapy. Immunohistochemistry of the cutaneous tumors revealed infiltration of CD20-negative lymphoma cells. A series of chemotherapy including high-dose MTX was ineffective, and the patient died in August 2003. Autopsy findings revealed the systemic intra-capillary infiltration of CD20 negative-lymphoma cells into multiple organs, including the lungs, liver, and kidneys. A CD20 negative-clone selected by rituximab therapy appeared to have expanded in this case.
    [Rinshō ketsueki] The Japanese journal of clinical hematology 11/2004; 45(10):1129-34.
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    ABSTRACT: E-cadherin gene is often termed a 'metastasis suppressor' gene and inactivation of this gene through promoter methylation occurs in various epithelial cancer. This study assessed the methylation status of p16INK4a and E-cadherin genes, correlated with clinical characteristics in lung cancer patients. Forty-five patients with non-small cell lung cancer (NSCLC) were evaluated for methylation status of p16INK4a and E-cadherin genes by using the methylation-specific PCR. E-cadherin expression in tumor samples was examined by immunohistochemistry. Overall duration of survival in different subsets of NSCLC with or without p16INK4a or E-cad methylation at diagnosis was compared by using the Kaplan-Meier method and log-rank test. We found the hypermethylation of p16INK4a gene in 38% (17/45) of our subjects. While the E-cadherin gene was hypermethylated in 62% (28/45) related with reduced E-cadherin expression, and methylation status of both p16INK4a and E-cadherin genes seemed to be independent. Seventy-six percent (34/45) of NSCLC patients had an abnormal methylation pattern in at least one gene. Although there was no difference in overall survival of patients between methylated p16INK4a and unmethylated p16INK4a, NSCLS patients with hypermethylation of both genes (concordant pattern) had a significantly good prognosis. In contrast, NSCLC patients with hypermethylated p16INK4a but un-methylated E-cadherin gene (discordant pattern) had a significantly poor prognosis. E-cadherin and p16INK4a are commonly methylated in NSCLC and the methylation pattern of p16INK4a and E-cadherin genes may have prognostic value for the outcome of NSCLC patients.
    Oncology Reports 09/2004; 12(2):389-95. · 2.30 Impact Factor
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    Leukemia 04/2004; 18(3):645-6. · 10.16 Impact Factor
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    ABSTRACT: The development of various kinds of autoimmune disease as a result of interferon-alpha (IFN-alpha) therapy has been reported among chronic myeloproliferative disorders(CMPD) including chronic myeloid leukemia(CML). Therefore, we investigated the frequency of autoimmune disorders in 33 patients with hematopoietic diseases treated with IFN-alpha in our department. Thirty-three patients (12 females, 21 males) included cases of CML (n = 23), essential thrombocythemia (ET) (n = 1), multiple myeloma (n = 8), and hypereosinophilic syndrome (HES) (n = 1). Autoantibodies (ANA, dsDNA, and RAPA), thyroid grand functions, and coagulant functions were examined. Twenty-five out of 33 patients were treated with natural IFN-alpha, and 8 patients were treated with recombinant IFN-alpha 2b (rIFN alpha-2b). Three patients were treated with IFN and anticancer agents. Antinuclear antibodies were detected in 2 of 33 patients. RAPA and anti-thyroglobulin antibody became positive in 3 and 4 patients, respectively. Ten patients showed low serum levels of either free T3 and/or free T4. However, none of them showed any clinical symptoms for developing autoimmune diseases. In addition, circulating anticoagulant antibodies were detected in 3 of 23 patients with CML treated with rIFN alpha-2b, but in no cases treated with natural IFN-alpha. Although none of the patients developed autoimmune diseases, we concluded that patients receiving IFN therapy should be carefully monitored for clinical signs and symptoms of autoimmune disorders.
    Gan to kagaku ryoho. Cancer & chemotherapy 12/2003; 30(12):1911-6.
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    ABSTRACT: The near-universal emergence of imatinib resistance in patients with acute forms of Philadelphia chromosome-positive leukemia highlights the need for additional therapy to control this disease. G3139 (Genasense, oblimersen; Genta Inc.), a Bcl-2 antisense oligonucleotide, has been shown to down-regulate the Bcl-2 protein and induce apoptosis in myeloid leukemia cells from treated patients. We tested G3139 for its ability to inhibit BCR-ABL-mediated transformation in mice. Nude mice (n = 5/group) were transplanted s.c. with imatinib-resistant BCR-ABL-transformed TF-1 cells (BCR-ABL-TF-1-R cells). Mice with established tumors (0.1 g) were treated for 14 days with G3139 (7 mg/kg/day i.p.), or with the reverse-sequence control oligonucleotide G3622 (7 mg/kg/day i.p.) or with imatinib (50 mg/kg/day i.p.). Mice treated with G3622 or imatinib died within 10-12 weeks. Nearly all of the mice treated with G3139 survived for >6 months and had reduced tumor volume. Three of the 5 mice showed complete tumor regression. A transient decrease in Bcl-2 protein was observed that correlated with histological evidence of apoptosis. In addition, we harvested BCR-ABL-TF-1-R tumor cells from mice treated with G3139 or control G3622 (7 mg/kg/day i.p., 7 days). Cells were then cultured with the antileukemic agents imatinib, daunorubicin, 1-beta-D-arabinofuranosylcytosine, or etoposide. G3139 pretreatment resulted in enhanced induction of apoptosis by all of the agents. These results suggest that G3139 is a promising candidate for treatment of patients with imatinib-resistant Ph-positive leukemia, and that combination of G3139 and imatinib may be useful to circumvent clinically acquired imatinib resistance.
    Clinical Cancer Research 09/2003; 9(11):4267-73. · 7.84 Impact Factor
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    ABSTRACT: We examined the efficacy of cyclosporin A (CsA) in 50 patients with myelodysplastic syndrome (MDS) consisting from 47 of RA, 1 of RARS, and 2 of RAEB. These patients showed various marrow cell types including hypo-, normo-, and hypercellularity. Patients belonged to the following International Prognostic Scoring System (IPSS) risk groups: 4 of low, 41 of intermediate-1, and 5 of intermediate-2. The median CsA dose was 4.58mg/kg, and treatment responses were classified according to the International Working Group (IWG) criteria. Hematological improvement (HI) was observed in 30 (60%) patients, and all of them were belonged to RA. In the patients with RARS or RAEB, no efficacy was observed. Four (8%) of the responders achieved partial remission (PR) with granulocytes > or = 1500microl(-1), Hb>11g/dl and platelets > or = 100,000microl(-1). Higher response rate (53%) was shown in erythroid lineage (HI-E) compared to platelet (HI-P, 36%) or neutrophil lineage (HI-N, 35%). When we analyzed the correlation between the response to CsA therapy and the karyotype or HLA type, there were significantly more responders with good karyotype or DRB1*1501 than with intermediate/poor karyotypes or with other HLA types. These results indicate the usefulness of CsA therapy for MDS patients with any marrow cellularity, especially for erythroid lineage and patients with good karyotype or DRB1*1501.
    Leukemia Research 09/2003; 27(9):783-8. · 2.76 Impact Factor
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    ABSTRACT: We examined the effects of a novel phenoxazine, 2-amino-4,4alpha-dihydro-4alpha,7-dimethyl-3H-phenoxazine-3-one (Phx), which was produced by the reaction of 2-amino-5-methyl-phenol with bovine hemoglobin on the proliferation of human endometrial adenocarcinoma cell lines, EN and KLE cells, and on induction of apoptosis and G2M arrest in these cells. Phx inhibited proliferation of these cell lines in a dose- and time-dependent manner, i.e., the inhibition rate of proliferation of EN and KLE cells was 43% and 40%, respectively, in the presence of 50 micro M Phx, and 75% and nearly 100%, in the presence of 100 micro M Phx, after 2 days. When these endometrial adenocarcinoma cells were incubated with a medium containing 100 micro M Phx for 24 h, accumulation of EN and KLE cells in the S and G2M phase and that of apoptotic cells were demonstrated by flow cytometry. Apoptosis of these cells caused by Phx was unlikely to be associated with p53, Bax, and Bcl-2, because the levels of these proteins were not altered regardless of the presence or absence of Phx. The present results suggest that Phx demonstrates antitumor activity against human endometrial adenocarcinoma cell lines EN and KLE cells, by inducing both cell cycle accumulation at S and G2M and apoptosis associated with p53, Bcl-2 and Bax insensitive pathways.
    Oncology Reports 09/2003; 10(5):1171-6. · 2.30 Impact Factor
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    ABSTRACT: A patient with myeloid/natural killer (NK) cell precursor acute leukemia who was also homozygous for protein C deficiency was treated and showed a complete remission while he simultaneously received low molecular weight heparin. He presented with fever spikes, lymphadenopathy, and a bulky tumor of the anterior mediastinum. A bone marrow aspirate showed the infiltration of immature lymphoblastoid cells. The patient's diagnosis was determined to be myeloid/NK cell precursor acute leukemia by morphologic and immunophenotypic analysis (CD7(+)CD33(+)CD34(+)CD56(+)). The patient developed a thrombosis in his jugular vein on cannulation of the internal jugular vein. An examination of the serum levels and the activities of proteins C and S demonstrated a slight decrease in the protein C level but an undetectable protein C activity. The patient received the diagnosis of homozygous protein C deficiency, because both parents were found to have heterozygous protein C activity. Treatment of the patient's leukemia included induction chemotherapy (Ara-C and idarubicin) with concomitant administration of low molecular weight heparin for his homozygous protein C deficiency. He achieved a complete remission without expressing any thrombosis during the course of chemotherapy. To our knowledge, this is the first case ever described in which acute myeloid leukemia was complicated with homozygous protein C deficiency.
    International Journal of Hematology 09/2003; 78(2):149-53. · 1.68 Impact Factor
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    ABSTRACT: The telomerase complex is responsible for telomere maintenance and represents a promising neoplasia therapeutic target. In order to determine whether G-quadruplex-interactive telomerase inhibitor, telomestatin (SOT-095), might have effects on telomere dynamics and to evaluate the clinical utility, we assessed the effects of telomestatin on BCR-ABL-positive human leukemia cells. We found that treatment with telomestatin reproducibly inhibited telomerase activity in the BCR-ABL-positive leukemic cell lines OM9;22 and K562, resulting in telomere shortening. Inhibition of telomerase activity by telomestatin disrupts telomere maintenance and ultimately results in telomere dysfunction. Telomestatin completely suppressed the plating efficiency of K562 cells at 1 microM; however, telomestatin had less effects on BFU-Es and CFU-GMs colony formation from normal bone marrow CD34-positive cells. Enhanced chemosensitivity toward imatinib and chemotherapeutic agents was also observed in telomestatin-treated K562 cells. Further, the combination of telomestatin plus imatinib more effectively inhibited hematopoietic colony formation by primary human chronic myelogenous leukemia cells. Last, telomestatin induced the activation of ATM and Chk2, and subsequently increased the expression of p21(CIP1) and p27(KIP1). These results demonstrate that telomere dysfunction induced by telomestatin activates the ATM-dependent DNA damage response. We conclude that telomerase inhibitors combined with the use of imatinib and other chemotherapeutic agents may be very useful for the treatment of human leukemia.
    Oncogene 09/2003; 22(34):5338-47. · 8.56 Impact Factor
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    ABSTRACT: Helicobacter pylori has recently been postulated to play a role in the pathogenesis of autoimmune diseases, including idiopathic thrombocytopenic purpura (ITP). We investigated the prevalence of H pylori infection and the effects of its eradication in 61 patients with ITP. H pylori infection was found in 50 patients (83%), an incidence significantly higher than not only healthy volunteers in Japan (60%) but also subjects in other reported ITP series (approximately 43%-71%). In our study, the mean age of H pylori-positive ITP patients (58.0 years) was significantly higher than that of H pylori-negative ITP patients (40.5 years). Bacterium eradication efforts were performed in 29 infected ITP patients and succeeded in 27 patients (93%). The 29 patients with eradicated H pylori infections showed significant increases in platelet counts compared with patients with uneradicated infections or who were H pylori-negative. During the follow-up period (median, 11.0 months), 16 (55%) of 29 patients achieved a major or a minor response. The patients who achieved a major response had not received previous prednisolone therapy, suggesting a relationship between prednisolone therapy and the response to eradication efforts. The assessment of H pylori infection and its eradication should be attempted in cases of ITP, because this approach may be a good new strategy for treating some ITP patients, especially elderly Japanese patients. Some regional factors have been suggested as causes of H pylori-associated ITP.
    International Journal of Hematology 05/2003; 77(3):239-44. · 1.68 Impact Factor
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    ABSTRACT: We determined T-cell receptor alpha-chain variable (TCRAV) and T-cell receptor beta-chain variable (TCRBV) region repertoires in peripheral bloods from patients with myelodysplastic syndrome (MDS) with erythroid hypoplasia. T-cells bearing TCR ADV14S1/BV5S2, AV21S1/BV21S4, and AV2S2/BV7S2 segments were markedly increased in three of four MDS patients, respectively. In addition, there was a positive relationship between the increase in the number of CD8-positive T-cells and the expression levels of these TCR transcripts. These findings suggest that CD8-positive T-cells monoclonally or oligoclonally expanded in the peripheral blood. We also determined the nucleotide and amino acid sequences of the complementarity-determining region 3 (CDR3) of TCR alpha- and beta-chains of the expanded T-cells. Unique sequences were detected in a high percentage of the respective CDR3 clones. The gene segment of the variable and joining regions, however, varied among the patients. The deduced amino acid sequences of CDR3 were heterogeneous among the patients, and there was no common motif. These results indicate there is monoclonal or oligoclonal proliferation of CD8-positive T-cells in MDS patients with erythroid hypoplasia, and suggest that these proliferating T-cells are responsible for the pathogenesis of the MDS entity.
    Leukemia Research 05/2003; 27(4):305-12. · 2.76 Impact Factor
  • Takashi Shimamoto, Kazuma Ohyashiki
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    ABSTRACT: The myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem cell disorders, while, immunological abnormalities are frequently observed in patients with MDS. Several reports revealed that about 10% of MDS patients have clinical autoimmune disorders like skin vasculitis, rheumatic disease, or autoimmune hemolytic anemia. Furthermore, serological immunological abnormalities like hyper- or hypogammaglobulinemia, positivities of antinuclear antibody, positivities of direct Coombs test, or inverted CD4/8 ratios were found in 18-65% of patients with MDS. Recently immunosuppressive therapies including prednisolone, antithymocyte globulin, and cyclosporin A (CsA) are used to treat cytopenia in some patients with MDS. We examined the efficacy of CsA in 50 patients with MDS. Hematologic improvement was observed in 30 (60%) patients especially for erythroid lineage. There were significantly more responders with good karyotype or DRB1*1501 than with intermediate/poor karyotypes or with other HLA types. MDS with erythroid hypoplasia is a rare form of MDS, and has not yet been clearly defined. We reported four patients with MDS with erythroid hypoplasia who had morphological evidence of myelodysplasia and low percentage of erythroid precursors. Rearrangements of the TCR-beta and -gamma genes were seen in these patients using Southern blot and PCR analysis. Also they had skewed TCR usages using TCR repertoire analysis. Their anemia drastically improved with CsA therapy. We have to establish the clinical usefulness of immunosuppressive therapy in MDS patients and simple tools for revealing T-cell mediated myelosuppression in the individual patients for decision-making.
    Leukemia and Lymphoma 05/2003; 44(4):593-604. · 2.61 Impact Factor
  • International Journal of Hematology 02/2003; 77(1):93-5. · 1.68 Impact Factor
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    ABSTRACT: Telomerase is a ribonucleoprotein enzyme that maintains protective structures at the ends of eukaryotic chromosomes. Earlier findings have supported an association between progressive telomere shortening in the chronic phase of chronic myelogenous leukemia and the up-regulation of telomerase activity occurring late in the evolution of the disease. We examined the impact of telomerase inhibition by dominant negative-human telomerase reverse transcriptase (DN-hTERT) on the biological features of BCR-ABL-transformed cells. We introduced vectors encoding DN-hTERT, wild-type (WT)-hTERT, or a control vector expressing only a drug-resistant marker into Philadelphia chromosome-positive K562 cells and OM9;22 cells and assessed the biological effect of telomerase inhibition on cellular immortality. Ectopic expression of DN-hTERT resulted in complete inhibition of telomerase activity and reduction of telomere length. The entire population of telomerase-inhibited K562 cells exhibited cytoplasmic blebbling and chromatin condensation, features of apoptosis. In contrast, K562 cells expressing WT-hTERT, which differ from the mutants by only two amino acids, exhibited normal morphology. The evidence of apoptosis in the telomerase-inhibited cells was determined by flow cytometric analysis with APO2.7 monoclonal antibody. We also observed enhanced induction of apoptosis by imatinib seen in DN-hTERT-expressing K562 cells, as compared with WT-hTERT-expressing cells. These results demonstrate that disruption of telomere maintenance limits the cellular life span of leukemia cells and show that the combined use of imatinib and telomere maintenance inhibition may be effective in the treatment of BCR-ABL-positive leukemia.
    Clinical Cancer Research 12/2002; 8(11):3341-7. · 7.84 Impact Factor
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    ABSTRACT: A 73-year-old woman with chronic myeloid leukemia was treated with interferon-alpha, hydroxyurea, and busulfan before imatinib mesylate treatment. The leukocyte count was 8,400/; hemoglobin concentration, 12.0 g/; and platelet count, 19.7 x 10(4)/. She received 400 mg of imatinib mesylate for 17 days before the agent was discontinued because of pancytopenia. A bone marrow biopsy on the 87th day after the last imatinib mesylate administration demonstrated severe hypocellularity. She needed many RBC and Plt transfusions and filgrastim administration. Grade 4 neutropenia continued for 35 days and Grade 3 thrombocytopenia continued for over 122 days. Imatinib mesylate, an agent targeting BCR-ABL, is expected to be useful as an effective therapeutic agent for chronic myeloid leukemia. However the present case suggests that its appropriate dose is individually variable and we should carefully consider the former treatment, and the clinical stage of the disease before initiating imatinib treatment.
    [Rinshō ketsueki] The Japanese journal of clinical hematology 10/2002; 43(9):868-70.

Publication Stats

821 Citations
241.02 Total Impact Points


  • 1999–2010
    • Tokyo Medical University
      • Department of Internal Medicine III
      Edo, Tōkyō, Japan
  • 1997–1999
    • State University of New York Downstate Medical Center
      • Department of Medicine
      Brooklyn, NY, United States