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Kazutaka Ozeki

Publications and source records attributed to Kazutaka Ozeki.

10 recordsLinked to original sources
PubMed2006

Establishment of a myeloid leukemia cell line, TRL-01, with MLL-ENL fusion gene.

We established a leukemia cell line derived from therapy-related acute myeloid leukemia with the t(11;19) by xenotransplantation into the NOD/SCID mouse with IL-2Rgamma(c)-/- (NOG mouse). The cell line, TRL-01, could be serially transplanted from mouse to mouse and also grown in an adherence-dependent manner on a murine bone marrow stroma cell line, HESS-5. TRL-01 had the same immunophenotype as the original leukemia cells: positive for CD13, CD33, CD11a, CD18, CD29, CD49d, CD49e, CD54, CD62L, and CD117, and negative for CD3, CD4, CD8, CD19, CD34, CD41a, CD41b, CD135, and myeloperoxidase. Translocation (11;19)(q23;p13) in both the original sample and TRL-01 generated MLL-ENL chimeric transcripts joining exon 6 and exon 4, respectively, which has a novel isoform. In cultures of TRL-01, addition of GM-CSF, SCF, and G-CSF and adhesion to fibronectin-coated plates promoted transient proliferation and survival, although they did not support long-term culture. Subcutaneous injection caused a tumor to form only when HESS-5 was coinjected at the same site. These results suggest that TRL-01 is a useful cell line for studying not only the leukemia-related biology of MLL-ENL but also the intercellular association between leukemia and stroma.

Adult↗
PubMed2006

Low-dose cyclosporin A with short-term methotrexate for graft-versus-host disease prophylaxis in allogeneic bone marrow transplantation from human leukocyte antigen-identical siblings: a prospective phase II study in Japanese patients.

We hypothesized that reducing the dosage of prophylaxis for graft-versus-host disease (GVHD) would reduce the risk of relapse and toxicity after bone marrow transplantation (BMT) from human leukocyte antigen (HLA)-identical siblings. In a prospective phase II trial, 21 patients with leukemia and myelodysplastic syndrome underwent BMT from HLA-identical siblings and received GVHD prophylaxis consisting of low-dose (1.5 mg/kg per day) cyclosporin A (CSP) with short-term methotrexate (MTX) treatment. This low-dose group was compared with a group of retrospective control patients (n = 22) who received a standard CSP dosage (3.0 mg/kg per day) and MTX. One patient died of transplantation-related causes within 100 days. The regimen-related toxicity was quite tolerable. Although acute GVHD of grades II to III was more frequent in the low-dose group (47.6%) than in the control group (22.7%), the increase in acute GVHD did not significantly contribute to morbidity or mortality. There were no differences between the groups in the incidence and severity of chronic GVHD. The probabilities of relapse and survival of the groups were similar according to the risk for relapse at the time of transplantation. A prospective randomized study is required to determine whether low-dose or standard-dose CSP in combination with MTX is optimal for Japanese patients who undergo allogeneic BMT from HLA-identical siblings.

Adolescent↗
PubMed2006

Establishment of a stroma-dependent human acute myelomonocytic leukemia cell line, NAMO-2, with FLT3 tandem duplication.

We have established a stroma-dependent myelomonocytic cell line, NAMO-2, with FLT3 internal tandem duplication (FLT3/ITD). Leukemia cells from a patient with acute myelomonocytic leukemia were administered to form subcutaneous tumors in nude mice, which were maintained successively, although we failed to establish continuously growing cells from the original leukemia cell culture. In the cultures of cells from subcutaneous tumors, there were stroma cells that had originated from the nude mice and showed continuous growth. The leukemia cells showed continuous growth dependent on this stroma, and this cell line was named NAMO-2. Detection of FLT3/ITD by the reverse transcriptase polymerase chain reaction (PCR) and genomic PCR showed that NAMO-2 was homozygous for FLT3/ITD. Constitutive activation of FLT3 was detected by Western blotting, and the phosphorylation of Akt, MEK, and STAT5 was also observed. FLT3 kinase inhibitor AG1296 specifically inhibited cell growth. NAMO-2 provides a useful tool to analyze adherence-dependent survival signaling of leukemia with FLT3/ITD and a model for the screening of FLT3 kinase inhibitors.

Animals↗
PubMed2005

Clinical characteristics and prognostic implications of NPM1 mutations in acute myeloid leukemia.

Recently, somatic mutations of the nucleophosmin gene (NPM1), which alter the subcellular localization of the product, have been reported in acute myeloid leukemia (AML). We analyzed the clinical significance of NPM1 mutations in comparison with cytogenetics, FLT3, NRAS, and TP53 mutations, and a partial tandem duplication of the MLL gene (MLL-TD) in 257 patients with AML. We found NPM1 mutations, including 4 novel sequence variants, in 64 of 257 (24.9%) patients. NPM1 mutations were associated with normal karyotype and with internal tandem duplication (ITD) and D835 mutations in FLT3, but not with other mutations. In 190 patients without the M3 French-American-British (FAB) subtype who were treated with the protocol of the Japan Adult Leukemia Study Group, multivariate analyses showed that the NPM1 mutation was a favorable factor for achieving complete remission but was associated with a high relapse rate. Sequential analysis using 39 paired samples obtained at diagnosis and relapse showed that NPM1 mutations were lost at relapse in 2 of the 17 patients who had NPM1 mutations at diagnosis. These results suggest that the NPM1 mutation is not necessarily an early event during leukemogenesis or that leukemia clones with NPM1 mutations are sensitive to chemotherapy.

Adolescent↗
PubMed2004

Usefulness of bone marrow aspiration for definite diagnosis of Asian variant of intravascular lymphoma: four autopsied cases.

The Asian variant of intravascular lymphoma (AIVL) is characterized by hemophagocytic syndrome, pancytopenia and hepatosplenomegaly but usually lacks any neurological abnormality and skin lesions, which are typical features of classical intravascular lymphoma (IVL). An ante-mortem diagnosis of AIVL is difficult due to the absence of visible lymphoma lesions and unspecific clinical manifestations. A definite diagnosis relies on the presence of neoplastic B cells in the lumina of small vessels. Paraffin block samples of aspirated bone marrow clots were obtained from 4 patients with clinically suspected IVL and subjected to immunohistopathological analysis. All samples exhibited CD 20+ or CD 79a+ lymphoma cells proliferating intravascularly as well as erythrocytic hemophagocytosis. The distribution of neoplastic cells in the structure of the bone marrow allowed IVL to be distinguished from bone marrow invasions due to other types of lymphoma. We demonstrated the successful establishment of a definite ante-mortem diagnosis of AIVL in 3 of 4 patients by the rapid and simple method of using aspirated bone marrow samples.

Aged↗
PubMed2004

Conditioning regimen of melphalan, fludarabine and total body irradiation in unmanipulated HLA haploidentical stem cell transplantation based on feto-maternal tolerance.

Unmanipulated hematopoietic stem cell transplantation from haploidentical family donors is frequently associated with graft failure and severe graft-versus-host disease (GVHD). We employed a myeloablative conditioning regimen consisting of 125 mg/m2 of fludarabine, 140 mg/m2 of melphalan and TBI of 10 to 12 Gy for three patients. The donor in each case was a haploidentical two-loci HLA mismatch mother or son. Engraftment failure was observed in one patient. In the other two patients, engraftment was confirmed within 15 days after transplantation. Acute and chronic GVHD was observed, but was controllable in both cases. HLA mismatched transplantation based on feto-maternal tolerance may provide an alternative option for patients who do not have HLA-matched donors.

Adult↗
PubMed2003

Biologic and clinical significance of the FLT3 transcript level in acute myeloid leukemia.

Although FLT3 mutations are essentially found in myeloid-lineage leukemia cells, a high level of FLT3 expression was recently observed in MLL gene-rearranged acute lymphoblastic leukemia without FLT3 mutations. Here, we analyzed the biologic and clinical significance of the FLT3 transcript level in comparison with several gene alterations in 181 de novo acute myeloid leukemia (AML) cases. The mean expression level in AML was higher than that in normal mononuclear cells, whereas the range varied widely. A high level of FLT3 is related to internal tandem duplication of the FLT3 gene (FLT3/ITD), the mutations within the activation loop of FLT3 (FLT3/D835Mt), and tandem duplication of the MLL gene (MLL-TD) but not to p53 or N-RAS gene mutations. Furthermore, a high expression level in AML cases with FLT3 mutations was not related to MLL-TD. Overexpressed FLT3 revealed autophosphorylation and had the same sensitivity to the FLT3 inhibitor as FLT3/ITD. Overexpression of FLT3 (more than 200,000 copies/microgRNA) was an unfavorable prognostic factor for overall survival in 91 AML cases without FLT3/ITD. These results indicated that FLT3 overexpression may distinguish a novel disease entity in AML without FLT3 mutations and serve as a therapeutic target for FLT3 inhibitors.

Adult↗
PubMed2003

Primary cutaneous diffuse large B cell lymphoma: a clinically aggressive case.

An 80-year-old woman was diagnosed with primary cutaneous B cell lymphoma. She had multifocal cutaneous tumors, but no nodal lymphadenopathy or bone marrow involvement. Histopathological examination of a biopsy specimen showed diffuse large B cell lymphoma without a bcl-2 expression. Complete resolution of hypercalcemia and disappearance of tumors were achieved with CHOP therapy, but a rapidly progressive skin lesion was observed soon after the completion of the therapy. The clinical manifestation of primary cutaneous diffuse large B cell lymphoma is diverse and the treatment strategy is not entirely clarified. This case represents another example of this rare lymphoma.

Aged↗
PubMed2003

[Systemic infection of Aspergillus flavus in a patient with acute lymphoblastic leukemia].

A 57-year-old woman with acute lymphoblastic leukemia (ALL) developed an antibiotics-resistant fever after remission induction therapy. Chest X-ray and computed tomography scan revealed multiple consolidations and cavities. Successively, numerous subcutaneous nodules and a thyroid mass emerged. Aspergillus flavus (A. flavus) was cultured from both sites. Despite the patient's granulocyte recovery, the fever persisted and multiorgan function deteriorated rapidly. However, she was successfully treated with intensive supportive therapy including continuous hemodialysis and filtration. Prolonged use of amphoterin B and itraconazole failed to cure her aspergillosis, but the illness remained indolent thereafter.

Amphotericin B↗