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Kazunori Ohnishi

Publications and source records attributed to Kazunori Ohnishi.

At least 19 recordsLinked to original sources
PubMed2006

Pharmacokinetics of arsenic species in Japanese patients with relapsed or refractory acute promyelocytic leukemia treated with arsenic trioxide.

PURPOSE: To investigate the pharmacokinetics of arsenic species in Japanese patients with relapsed or refractory acute promyelocytic leukemia (APL) treated with arsenic trioxide (ATO) at a daily dose of 0.15 mg/kg. METHODS: Inorganic arsenic (AsIII and AsV) and the major metabolites monomethylarsonic acid (MAA(V)) and dimethylarsinic acid (DMAA(V)) in plasma and urine collected from 12 Japanese patients were quantified by HPLC/ICP-MS. RESULTS: The plasma concentrations of AsIII and AsV on day 1 reached the similar Cmax (12.4 +/- 8.4 and 10.2 +/- 3.9 ng/ml) immediately after completion of administration followed by a biphasic elimination. The AUC(0-infinity) of AsV was about twice that of AsIII. The appearance of methylated metabolites in the blood was delayed. During the repeated administration, the plasma concentrations of inorganic arsenic reached the steady state. In contrast, the MAA(V) and DMAA(V) concentrations increased in relation to increased administration frequency. The mean total arsenic excretion rate including inorganic arsenic and methylated arsenic was about 20% of daily dose on day 1 and remained at about 60% of daily dose during week 1-4. CONCLUSIONS: This study demonstrates that ATO is metabolized when administered intravenously to APL patients and methylated metabolites are promptly eliminated from the blood and excreted into urine after completion of administration, indicating no measurable accumulation of ATO in the blood.

Adult↗
PubMed2006

Role for interleukin-6 and insulin-like growth factor-I via PI3-K/Akt pathway in the proliferation of CD56- and CD56+ multiple myeloma cells.

OBJECTIVES: Several studies including ours have suggested that lack of CD56 in multiple myeloma (MM) defines a unique patient subset with poorer prognosis. However, the mechanism underlying this aggressive behavior of CD56(-) MM has not been well elucidated. Interleukin-6 (IL-6) or insulin-like growth factor I (IGF-I) induce proliferation of MM cells. In this study, we report about the relationship between CD56 expression and responsiveness to these cytokines. METHODS: We sorted out both CD56(-) and CD56(+) fractions from MM cell lines such as KMS-21-BM and U-266, and investigated their different responsiveness to IL-6 or IGF-I. Furthermore, we compared the effects of these cytokines on the regulation of cell-cycle distribution between CD56(-) and CD56(+) cells. RESULTS: Although CD56(-) cells in both KMS-21-BM and U-266 cells responded significantly to IL-6, CD56(+) cells did not. Ki-67(+) cells in the CD56(-) cells were significantly increased by IL-6. Western blotting showed that IL-6 phosphorylated Akt, and upregulated and downregulated the level of cyclin D1 and p27 protein in the CD56(-) KMS-21-BM cells, respectively. LY-294002 completely blocked these effects of IL-6. On the other hand, Ki-67(+) cells in the CD56(+) cells did not respond to IL-6. Anti-IGF-I mAb significantly reduced Ki-67(+) cells only in the CD56(+) cells. IGF-I phosphorylated Akt and upregulated cyclin D1 in the CD56(+) KMS-21-BM cells, which was completely blocked by LY294002. CONCLUSIONS: These results suggest that CD56(-) and CD56(+) MM cells could be stimulated by IL-6 and IGF-I, respectively, via PI3-K/Akt pathway, and provide useful information for anticytokine therapies.

Antibodies, Monoclonal↗
PubMed2006

Clinicopathological and prognostic characteristics of CD33-positive multiple myeloma.

There have been few reports about the CD33 expression on multiple myeloma (MM) cells so far, showing that only a few patients expressed CD33 homogenously on their MM cells. However, in these reports, neither detailed clinical information nor its prognostic significance was described. Therefore, we analyzed the CD33 expression on MM cells from 63 newly diagnosed patients by flow cytometry and the correlation with other clinical parameters to determine the clinicopathological significance of this molecule. Fourteen (22%) patients were positive for CD33. Of the 14 patients with CD33+ MM, >80% of MM cells were positive in six (9.5%). The CD33+ patients had higher beta 2 microglobulin and lactate dehydrogenase levels and higher incidence of anemia and thrombocytopenia than did CD33- patients. The estimated 3-yr overall survival in CD33+ patients was significantly lower than in the CD33- ones (31% and 50%, respectively, P = 0.042). Especially, mortality within a year from diagnosis in the CD33+patients was higher than that in CD33- patients (43% and 10%, respectively, P = 0.005). Serial evaluation of CD33 expression showed that the amount of CD33 significantly increased after a variety of treatment including melphalan and steroid in individual patients. These results suggest that the CD33 expression might be associated with drug resistance to these conventional agents, and CD33 might be a useful target for the development of new therapeutic agents in MM.

Adult↗
PubMed2006

Arrhythmogenic effects of arsenic trioxide in patients with acute promyelocytic leukemia and an electrophysiological study in isolated guinea pig papillary muscles.

BACKGROUND: Arsenic trioxide (As(2)O (3)) is a new promising regimen for patients with a relapse of acute promyelocytic leukemia (APL), but causes life-threatening arrhythmias. This study aimed to investigate the incidence and mechanism of arrythmogenesis caused by As(2)O(3). METHODS AND RESULTS: Standard 12-lead ECGs were monitored throughout As(2)O(3) therapy in 20 APL patients. As(2)O (3) (0.15 mg/kg) significantly prolonged the corrected QT interval (QTc: 445+/-7 to 517+/-17 ms, means+/-SE, p<0.01), and also increased the QTc dispersion and transmural dispersion of repolarization. Non-sustained ventricular tachycardias and torsades de pointes occurred in 4 and 1 patients, respectively. The action potentials and isometric contraction were measured in guinea pig papillary muscles during As(2)O (3) perfusion (350 micromol/L). The action potential duration was prolonged (APD(90): 150+/-11 to 195+/-12 ms at 60 min, p<0.01, n=5) and perfusion of As(2)O(3) in a low K(+) solution with a low stimulation rate augmented the prolongation of APD, and provoked early after-depolarizations and triggered activities. The prolonged exposure to As(2)O(3) induced muscle contracture, aftercontractions, triggered activities and electromechanical alternans. Tetrodotoxin or butylated hydroxytoluene partially prevented the As(2)O(3)-induced prolongation of APD. CONCLUSIONS: The prolonged QTc and spatial heterogeneity are responsible for the As(2)O(3)-induced ventricular tachyarrhythmias. In addition to prolongation of the APD, cellular Ca(2+) overload and lipid peroxidation might contribute to the electrophysiological abnormalities caused by As(2)O(3).

Action Potentials↗
PubMed2006

Two cases of acute promyelocytic leukemia complicated by torsade de pointes during arsenic trioxide therapy.

We describe 2 patients with acute promyelocytic leukemia (APL) in whom torsade de pointes (TdP) developed during treatment with arsenic trioxide. Patient 1 was a 23-year-old woman with second-relapse APL. Ventricular premature beat bigeminy developed on day 27 of treatment, and episodes of TdP developed on day 28. Patient 2 was a 51-year-old woman with second-relapse APL who had cardiomyopathy due to prior anthracycline treatment. TdP developed on day 17 of treatment. Arsenic trioxide is known to cause electrocardiographic abnormalities, such as ventricular tachycardia and prolongation of QT interval. Patient 1 was given fluconazole as a concomitant drug. Patient 2 had cardiomyopathy and hypokalemia. Careful management is needed during arsenic trioxide therapy because this treatment prolongs the QT interval, possibly inducing episodes of TdP.

Adult↗
PubMed2005

Etodolac induces apoptosis and inhibits cell adhesion to bone marrow stromal cells in human myeloma cells.

OBJECTIVES: Cyclooxygenase-2 (COX-2) is reported to regulate apoptosis and to be an important cellular target for therapy. METHODS: We examined whether etodolac, meloxicam, and thalidomide inhibited proliferation and induced apoptosis in myeloma cell lines (RPMI 8226 and MC/CAR cells). RESULTS: Etodolac induced apoptosis more strongly compared with thalidomide or meloxicam. Etodolac induced down-regulation of Bcl-2 protein and mRNA, activation of Caspase-9, -7 and -3, cIAP-1 and Survivin, and loss of mitochondrial membrane potential in a dose-dependent manner. In addition, when myeloma cells were coincubated with 50 microM etodolac on bone marrow stromal cells (BMSCs), myeloma cell adhesion to BMSCs was significantly inhibited compared with thalidomide or meloxicam coincubation, and the adhesion molecules VLA-4, LFA-1 (CD11a), CXCX4, and CD44 were suppressed on myeloma cells treated with etodolac. Moreover, 50-100 microM racemate of etodolac significantly inhibited the proliferation of myeloma cells compared to 100 microM R-etodolac or S-etodolac. CONCLUSIONS: Etodolac induced loss of mitochondrial membrane potential and apoptosis via a COX-2-independent pathway, suppressed the expression of adhesion molecules, and inhibited myeloma cell adhesion to BMSCs compared with thalidomide or meloxicam. The activities of etodolac potentially extend to the treatment of patients with myeloma resistant to standard chemotherapy, including thalidomide.

Apoptosis↗
PubMed2005

Etodolac inhibits EBER expression and induces Bcl-2-regulated apoptosis in Burkitt's lymphoma cells.

Cyclooxygenase-2 (COX-2) is reported to be an important cellular target for therapy in malignancies. The growth inhibitory effects of COX-2 inhibitors on malignancies have been demonstrated to be through not only COX-2 dependent, but also independent mechanisms. In this study, we showed that etodolac, COX-2 inhibitor, induced apoptosis via COX-2 independent pathway, and investigated the molecular details of etodolac-induced apoptosis in Burkitt's lymphoma cells. In Daudi and Raji Burkitt's lymphoma cell lines, which expressed no COX-2 enzyme, etodolac more strongly induced apoptosis compared to meloxicam. Moreover, etodolac did not induce apoptosis to normal B-lymphocytes. For the pathway of etodolac-induced apoptosis, reduction of anti-apoptotic bcl-2 mRNA and Bcl-2 protein, activation of Caspase-9 and -3, down-regulation of caspase inhibitors, c-IAP-1 and Survivin were involved. Moreover, EBER-1 and -2 expression in Epstein-Barr virus positive Daudi and Raji cells were reduced to result in down-regulation of Bcl-2 by treatment with etodolac. It has been reported that etodolac has stereoisomers, R- and S-etodolac. We found that racemate of etodolac more strongly induced apoptosis in Daudi and Raji cells compared to R- or S-etodolac. In conclusion, our findings indicated etodolac inhibited EBERs expression and induced apoptosis via a Bcl-2-regulated pathway. Moreover, racemate of etodolac more effectively induced apoptosis than R- and/or S-etodolac. Therefore, these activities of etodolac potentially extend to the treatment of patients with Burkitt's lymphoma resistant to chemotherapy.

Apoptosis↗
PubMed2005

Arsenic trioxide therapy in relapsed or refractory Japanese patients with acute promyelocytic leukemia: updated outcomes of the phase II study and postremission therapies.

Recently, arsenic trioxide (ATO) has been proved to induce complete remission (CR) at a high rate in patients with acute promyelocytic leukemia (APL). We prospectively investigated the safety and efficacy of ATO therapy in patients with relapsed and refractory APL and examined the duration of CR and the postremission therapies. Initially, 0.15 mg/kg ATO was administered until bone marrow remission to a maximum of 60 days. After the patient achieved CR, 1 additional ATO course at the same dosage was administered for 25 days. Of 34 patients, 31 (91%) achieved CR. PML-RAR3 messenger RNA was not detected in the bone marrow of 18 (72%) of the 25 patients evaluated by reverse transcriptase-polymerase chain reaction analysis. At a median follow-up of 30 months, the estimated 2-year overall survival rate was 56%, and the estimated 2-year event-free survival rate was 17%. During the ATO therapy, QTc prolongation was observed in most cases. Fifteen patients developed ventricular tachycardia, and 1 of them showed torsades de pointes. Other adverse events were nausea, water retention, APL differentiation syndrome, skin eruption, liver dysfunction, and peripheral neuropathy, all of which were quite tolerable. ATO therapy was remarkably effective for relapsed APL; however, postremission therapies were necessary to maintain a durable remission.

Adolescent↗
PubMed2005

Two patients with all-trans retinoic acid-resistant acute promyelocytic leukemia treated successfully with gemtuzumab ozogamicin as a single agent.

Acute promyelocytic leukemia (APL) cells express a considerable level of CD33, which is the target of gemtuzumab ozogamicin (GO), and a significantly lower level of P-glycoprotein (P-gp). Therefore, GO is predicted to be a successful treatment for APL. In this article, we report on the GO treatment of 2 patients with APL, who had fully relapsed after induction therapy with all-trans retinoic acid (ATRA) following chemotherapy. Both patients had relapsed 3 times and were resistant to reinduction therapy with ATRA. GO (9 mg/m2) was administered on days 1 and 15. After GO treatment, both patients achieved complete hematologic and molecular remission. GO may be another promising agent for the treatment of ATRA-resistant relapsed APL when given as salvage chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Delayed recovery of normal hematopoiesis in arsenic trioxide treatment of acute promyelocytic leukemia: a comparison to all-trans retinoic acid treatment.

OBJECTIVE: To examine laboratory data including total blood cell count, leukocyte morphology and coagulation parameters during treatment for acute promyelocytic leukemia (APL) at a single institute, and compare the precise differences between all-trans retinoic acid (ATRA) and arsenic trioxide (As2O3) treatment. PATIENTS AND METHODS: Sixteen patients with APL who were treated with ATRA or As2O3 alone and achieved complete remission (CR) were analyzed. ATRA 45 mg/m2/day was given orally until CR. As2O3 0.15 mg/kg/day was given intravenously until leukemic blasts and promyelocytes were eliminated from the bone marrow. RESULTS: All 7 patients in the ATRA-treated group were primary cases and all 9 patients in the As2O3-treated group were relapsed cases after the achievement of CR with the ATRA. There was no difference in the data before treatment between these two groups. The duration of leukocytopenia and neutropenia during As2O3 treatment was significantly longer than those of ATRA treatment. The nadir of leukocyte and neutrophil counts was observed later in the As2O3-treated group. Terminal neutrophil differentiation was observed more obviously in the ATRA-treated group. The red blood cell count and hemoglobin concentration decreased significantly at the end of As2O3 treatment and were lower than those of ATRA treatment. Platelets recovered earlier in the ATRA-treated group. Coagulation parameters were not significantly changed between the two groups. CONCLUSION: In comparison with ATRA treatment, the recovery of several components in the peripheral blood cells was delayed in As2O3 treatment. Therefore we should pay more and longer attention in As2O3 treatment.

Antineoplastic Agents↗
PubMed2005

High dose chemotherapy and stem cell support in a patient of light- and heavy-chain deposition disease with abnormal marrow cell surface antigens and no monoclonal protein.

A 53-year-old man with nephrotic syndrome and severe renal failure was diagnosed with light- and heavy-chain deposition disease (LHCDD) by renal biopsy. The patient had no monoclonal protein and mild marrow plasmacytosis (6%), but marrow plasma cells expressed CD19(-)CD56+ and predominant monoclonal kappa-chain, indicating plasma cell dyscrasia. Conventional chemotherapy was ineffective and did not improve renal failure. High dose chemotherapy/peripheral blood stem cell transplantation (HDC/PBSCT) was introduced even after hemodialysis to eliminate aberrant clone and normalization of bone marrow cell surface markers. Immunophenotypic analysis of marrow cells facilitates clinical decision making regarding the use of HDC/PBSCT for LHCDD patients without monoclonal protein.

Antigens, CD19↗
PubMed2005

The impact of the combination of baseline risk group and cytogenetic response on the survival of patients with chronic myeloid leukemia treated with interferon alpha.

BACKGROUND AND OBJECTIVES: This study was aimed at examining major cytogenetic response (MCR) as a valid predictor of the course of chronic myeloid leukemia (CML) and at assessing the survival of CML patients treated with interferon alpha (IFN) in dependence on the combination of MCR (yes or no) with the baseline risk group of the New CML score. MCR was defined as a reduction of Philadelphia chromosome-positive bone marrow cells to <or= 35%. The New CML score discriminated three risk groups with significantly different survival probabilities. DESIGN AND METHODS: Data from individual patients with a confirmed diagnosis of Philadelphia chromosome-positive CML treated with IFN were collected from 10 prospective studies in Europe and Japan. Stratified for baseline risk group, patients with a major cytogenetic response by 21 months after the start of therapy (n=171) were compared with patients achieving a minor response or less (n=487). Survival probabilities after the landmark at 21 months were compared by using the two-sided log-rank test. RESULTS: MCR was a major predictor for low- and intermediate-risk patients (log-rank test, p <or= 0.0001), but not for high-risk patients. Ten-year survival probabilities for the low- and intermediate-risk patients who had a MCR were 75% (95 CI: 65-86%) and 56% (95 CI: 37-75%), respectively. The corresponding probabilities for patients who did not achieve a MCR were 21% (95 CI: 6-35%) and 16% (95 CI: 6-25%). INTERPRETATION AND CONCLUSIONS: Cytogenetic response per se is not a valid surrogate marker, as it is dependent on the baseline prognostic profile. The combination of risk group and cytogenetic response does, however, provide useful clinical information. The survival data presented here can serve as a benchmark for the assessment of the long-term effectiveness of imatinib.

Adult↗
PubMed2005

[Current and new therapeutic strategies in acute myeloid leukemia].

Seventy to 80% of patients with acute myeloid leukemia (AML) achieve complete remission (CR) by chemotherapy, but more than 50% of them then relapse. Phase III clinical trials in the treatment of patients with previously untreated AML and acute promyelocytic leukemia (APL) are ongoing in Japan (JALSG AML 201, APL 204). And continuous efforts are being made to improve the efficacy of chemotherapy. We discussed six topics in the treatment of AML. (1) To determine whether adding the MDR-1 modulator to chemotherapy provided clinical benefits to patients with AML and high-risk myelodysplastic syndrome (MDS), a phase III randomized study was performed using PSC 833. CR rates and overall survival (OS) were not improved by using PSC 833 compared to chemotherapy alone. (2) A large randomized study selectively focused on the G-CSF priming was performed. Among patients in this study attaining CR, the probability of relapse was reduced when they had been assigned to treatment with G-CSF along with induction chemotherapy. The benefit of chemotherapy-sensitization by G-CSF was particularly evident among the intermediate-risk. (3) Fludarabine in addition to Ara-C increases the accumulation of Ara-CTP, which is responsible for the cytotoxic effect in leukemic blasts. In a randomized phase III trial, patients with high-risk MDS or patients with AML were randomized to receive 2 induction courses consisting of Ara-C and G-CSF during and after chemotherapy with or without fludarabine (FLAG versus AG). Although Ara-CTP accumulation in leukemic cells after FLAG was enhanced, the clinical outcome in terms of CR rate, OS, event-free survival, and disease-free survival was not significantly improved by combining fludarabine with Ara-C. (4) Calicheamicin-conjugated humanized anti-CD 33 mouse monoclonal antibody, mylotarg, has recently been introduced. In combined phase II studies of 277 patients with CD 33-positive AML in their first relapse, the overall response rate was 26%. (5) Arsenic trioxide (ATO) has been established as a highly effective therapy for patients with APL, even for those with disease refractory to ATRA. ATO was recently approved in Japan. (6) There has been great interest in developing FLT 3 inhibitors because of the high frequency and poor prognosis of AML patients with mutant FLT 3. Some compounds are currently under development.

Acute Disease↗
PubMed2005

[Clinical course of the disease and the level of WT1 mRNA in 191 patients with acute myeloid leukemia (AML): joint research by 23 institutions in Japan].

We evaluated the clinical course of acute myeloid leukemia (AML) and the levels of WT1 mRNA in 191 AML patients. Of 114 previously untreated patients with AML, 107 cases were positive for WT1 mRNA (93.9% : 107/114). WT1 mRNA expression-levels declined to below 50 copies/microg RNA ("negative") after remission was achieved in all 66 patients who achieved remission and 84.8% (47/54) cases were "negative" at the end of the follow-up periods. On the other hand, WT1 mRNA was expressed in 87.0% of non-remission cases (47/54), maintaining 50 copies/microg of RNA or higher ("positive"). In all 29 cases who relapsed during the follow-up observation period after achieving remission, WT1 mRNA levels declined transiently approximately around the time of achieving remission and then rose again when the disease relapsed. Moreover, we determined the time of elevation of WT1 mRNA in 29 relapsed cases. In 79.3% of relapsed cases (23/29), WT1 mRNA levels rose above 200 copies/microg RNA, 43 days (median) before the diagnosis of "relapse". Given the percent of the correct diagnosis, WT1 mRNA at 200 copies/microg RNA appeared to be a reasonable cut-off level for early detection of AML-relapse. The WT1 mRNA level reflected the clinical condition. Taken together, these findings indicate that WT1 mRNA levels allow us to detect the presence of so-called "minimal residual disease" (leukemic cells) that cannot be detected by morphological examination. Besides these promising data, this kit is suitable for routine monitoring of AML because this kit utilizes peripheral blood as a test specimen, reducing the patient's burden at the time of collection of clinical samples as compared with bone marrow aspirate.

Adult↗
PubMed2004

Disease-related potential of mutations in transcriptional cofactors CREB-binding protein and p300 in leukemias.

CREB-binding protein (CBP) and highly related p300 protein are transcriptional co-activators that play an essential role in chromatin remodeling through histone acetyltransferase activity and interaction with other transcriptional regulators. In this study, various hematological malignancies, including nine cell lines and 45 clinical samples (32 acute myeloid leukemias (AML), nine acute lymphoblastic leukemias (ALL), two cases of myelodysplastic syndrome (MDS), one multiple myeloma, and one chronic myelogenous leukemia in blast crisis), were examined to ask whether mutation of the CBP and p300 genes could be involved in leukemogenesis. The answer was approached by employing the reverse transcription-polymerase chain reaction and single-strand conformation polymorphism (RT-PCR/SSCP) technique and subsequent sequence analysis. A T-lymphoblastic cell line, CEM had an in-frame 21-base-pair deletion within the bromodomain of its p300 cDNA. Genomic DNA analysis revealed aberrant splicing caused by mutation of the acceptor site of intron 17 from ag to gg, which should interfere with catalytic step II of the pre-mRNA splicing reaction. In 1 MDS patient, a missense mutation was detected, which caused a replacement from Ser to Gly at codon 507 of p300. This is the first report of CBP/p300 mutations in leukemias, which might be relatively rare but nonetheless contribute to pathogenesis in some fraction of cases.

Acetyltransferases↗