Mayumi Yoshimi

The University of Tokyo, Tokyo, Tokyo-to, Japan

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Publications (7)16.31 Total impact

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    ABSTRACT: We report a case of myeloid/natural killer cell precursor acute leukemia. A 68-year-old man was diagnosed as having lymphoma in his neck, and was referred to our department for further examination and treatment. After admission, blastoid-cells appeared and increased rapidly in his peripheral blood. Cell marker analysis revealed that the blastoid-cells expressed CD7, CD56, CD33, and CD34. He was then diagnosed with myeloid/natural killer cell precursor leukemia. This form of leukemia was recently established as a distinct disease entity. Further clinicopathological evaluation and the establishment of treatment are necessary.
    [Rinshō ketsueki] The Japanese journal of clinical hematology 01/2013; 54(6):579-583.
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    ABSTRACT: RUNX1 is essential for definitive hematopoiesis and T-cell differentiation. It has been shown that RUNX1 is phosphorylated at specific serine and threonine residues by several kinase families. However, it remains unclear whether RUNX1 phosphorylation is absolutely required for its biological functions. Here, we evaluated hematopoietic activities of RUNX1 mutants with serine (S)/threonine (T) to alanine (A), aspartic acid (D), or glutamic acid (E) mutations at phosphorylation sites using primary culture systems. Consistent with the results of knockin mice, RUNX1-2A, carrying two phospho-deficient mutations at S276 and S293, retained hematopoietic activity. RUNX1-4A, carrying four mutations at S276, S293, T300, and S303, showed impaired T-cell differentiation activity, but retained the ability to rescue the defective early hematopoiesis of Runx1-deficient cells. Notably, RUNX1-5A, carrying five mutations at S276, S293, T300, S303, and S462, completely lost its hematopoietic activity. In contrast, the phospho-mimic proteins RUNX1-4D/E and RUNX1-5D/E exhibited normal function. Our study identifies multiple phosphorylation sites that are indispensable for RUNX1 activity in hematopoiesis.
    European Journal of Immunology 04/2012; 42(4):1044-50. · 4.97 Impact Factor
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    ABSTRACT: Spermatic cord lymphoma is a rare lethal disease. It has a poor prognosis even in stage I or II disease when treated locally, therefore, multidisciplinary treatment for early stage is recommended. On the other hand, the treatment of choice for stage III or IV spermatic cord lymphoma remains to be determined. It is said that spermatic cord lymphoma is clinicopathologically similar to primary testicular lymphoma, therefore the treatment of spermatic cord lymphoma has often been determined by reference to the recommended treatment for primary testicular lymphoma. Here we report a new case of spermatic cord lymphoma, which was found in stage IV disease. We also review thirty-three cases which have been reported as spermatic cord lymphoma to date, and discuss treatment options.
    Case Reports in Medicine 01/2012; 2012:513707.
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    ABSTRACT: The vascular endothelial growth factor (VEGF)-C system was analyzed in two cases of acute lymphocytic leukemia (ALL) with TCF3/PBX1 fusion to determine whether the VEGF-C system influences the growth of these ALL blasts. Bone marrow non-adherent mononuclear cells were prepared from the patients, and expressions of VEGFs and VEGF receptors (VEGFRs) were analyzed based on RNA and protein levels. Cell proliferation was also assayed with or without neutralizing antibodies to VEGFs. The patients' leukemic blasts expressed a significant amount of VEGF-C and VEGFR type-3. When anti-VEGF-C antibody was added to the blast cell cultures, cell proliferation was suppressed. These observations indicate that, in our ALL cases with TCF3/PBX1 fusion, VEGF-C autocrine stimulation plays an important role in the proliferation of ALL.
    International journal of hematology 08/2011; 94(2):203-8. · 1.17 Impact Factor
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    ABSTRACT: Acute eosinophilic pneumonia (AEP) is an acute febrile illness with respiratory impairment, diffuse pulmonary infiltrates, and eosinophilia in bronchoalveolar lavage (BAL) fluid. We report an adult male who developed severe cough and dyspnea with slight fever on day 78 after allogeneic hematopoietic stem transplantation. The symptoms coexisted with skin and gut GVHD. The imaging test demonstrated interstitial infiltrates and BAL analysis revealed marked increase of eosinophils and no sign of infection. We made a diagnosis of AEP and steroid was started. AEP remitted with other GVHD symptoms but exacerbated partially when steroid was decreased. This case suggests a potential link between AEP and GVHD.
    International journal of hematology 02/2009; 89(2):244-8. · 1.17 Impact Factor
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    ABSTRACT: Evi-1 is a zinc-finger transcriptional factor whose inappropriate expression leads to leukemic transformation in mice and humans. Recently, it has been shown that Evi-1 regulates proliferation of hematopoietic stem/progenitor cells at embryonic stage via GATA-2 up-regulation; however, detailed mechanisms underlying Evi-1-mediated early hematopoiesis are not fully understood. We therefore evaluated hematopoietic potential of Evi-1 mutants using a cultivation system of murine para-aortic splanchnopleural (P-Sp) regions, and found that both the first zinc finger domain and the acidic domain were required for Evi-1-mediated hematopoiesis. The hematopoietic potential of Evi-1 mutants was likely to be related to its ability to up-regulate GATA-2 expression. We also showed that the decreased colony forming capacity of Evi-1-deficient P-Sp cells was successfully recovered by inhibition of TGF-b signaling, using ALK5 inhibitor or retroviral transfer of dominant-negative-type Smad3. Our findings suggest that Evi-1 promotes hematopoietic stem/progenitor expansion at the embryonic stage through up-regulation of GATA-2 and repression of TGF-beta signaling.
    Cancer Science 08/2008; 99(7):1407-13. · 3.48 Impact Factor
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    ABSTRACT: Intrathymic development of CD4/CD8 double-negative (DN) thymocytes can be tracked by well-defined chronological subsets of thymocytes, and is an ideal target of gene expression profiling analysis to clarify the genetic basis of mature T cell production, by which differentiation of immature thymocytes is investigated in terms of gene expression profiles. In this study, we show that development of murine DN thymocytes is predominantly regulated by largely repressive rather than inductive activities of transcriptions, where lineage-promiscuous gene expression in immature thymocytes is down-regulated during their differentiation. Functional mapping of genes showing common temporal expression profiles implicates previously uncharacterized gene regulations that may be relevant to early thymocytes development. A small minority of genes is transiently expressed in the CD44(low)CD25(+) subset of DN thymocytes, from which we identified a novel homeobox gene, Duxl, whose expression is up-regulated by Runx1. Duxl promotes the transition from CD44(high)CD25(+) to CD44(low)CD25(+) in DN thymocytes, while constitutive expression of Duxl inhibits expression of TCR beta-chains and leads to impaired beta selection and greatly reduced production of CD4/CD8 double-positive thymocytes, indicating its critical roles in DN thymocyte development.
    The Journal of Immunology 11/2007; 179(8):5335-45. · 5.52 Impact Factor