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Y Okimoto

Publications and source records attributed to Y Okimoto.

At least 37 records · Page 2Linked to original sources
PubMed1999

Clinical and biological aspects of acute lymphoblastic leukemia in 62 infants: retrospective analysis of the Tokyo Children's Cancer Study Group.

BACKGROUND: As a first step to formulate a new treatment strategy for refractory acute lymphoblastic leukemia (ALL) in infants, clinical results and immunophenotypic and cytogenetic data were analyzed and compared with those from overseas. METHODS: There were 62 infants with ALL who were treated between 1977 and 1995 at 30 institutions affiliated with the Tokyo Children's Cancer Study Group. Clinical and laboratory data obtained from these infants (all under 1 year of age) were retrospectively studied. RESULTS: The morphological diagnoses were FAB-L1 for 51 patients (82.2%) and FAB-L2 for 11 patients (17.8%). Hepatomegaly and splenomegaly were found in 40 (70.0%) and 40 patients (68.3%), respectively. The mean (+/- SEM) leukocyte count at diagnosis was 205,900 +/- 35,700/microL. The involvement of the central nervous system was evident in nine of 36 patients who were subjected to lumbar puncture, while three of these nine patients were free of neurological symptoms at diagnosis. Thirty-one patients (55.4%) were CD10 negative and 14 (25.0%) were CD10 positive. Thirty-one of 47 patients (65.9%) exhibited chromosomal abnormalities, including 28 patients (59.6%) with 11q23 abnormalities. Rearrangements in the MLL gene were found in nine of 13 infants (69.2%) examined. Translocation of 11q23 and/or MLL gene rearrangement (11q23/MLL) was significantly associated with the absence of the CD10 antigen. Hyperleukocytosis of more than 50,000/microL and 11q23/MLL gene rearrangements were related to a poor prognosis. The probability of an event-free survival in 62 infants was 13.1 +/- 4.8% at 48 months. CONCLUSIONS: New therapeutic strategies and large-scale cooperative prospective trials are needed to improve the prognosis of ALL in infants.

Chromosomes, Human, Pair 11↗
PubMed1998

Cord blood transplantation from sibling donors in Japan. Report of the national survey.

A joint national survey on cord blood transplantation (CBT) was conducted in Japan and 18 sibling CBTs were reported. Diseases of the patients were leukemia (ten), neuroblastoma (one), bone marrow failure (four) and inborn errors of metabolism (three). A volume of 50-141 ml of cord blood containing 27-197 x 10(7) nucleated cells was collected from sibling infants soon after delivery. HLA antigens were identical in 14 and one to three antigens mismatched in four. Engraftment of donor cord blood was achieved in 17 cases. Autologous hematopoiesis was recovered in one case. Days of engraftment were 13-29 days (median 19 days) for neutrophils (500/microliter), 18-67 days (median 30 days) for reticulocytes (2%) and 21-96 days (median 46 days) for platelets (50 x 10(3)/microliter). Acute GVHD was grade 0 in seven cases, grade I in five cases and grade II in one case in HLA-identical pairs, but became grade II in two cases and grade III in two cases in HLA-mismatched pairs. Chronic GVHD of limited type developed in two out of 17 evaluable cases, however both responded to immunosuppressive therapy. Altogether, 14 out of 18 patients are currently surviving 4-27 months following transplantation. Probabilities of overall survival and disease free survival were estimated to be 77.0 and 71.8% using Kaplan-Meier tests. These findings suggest the feasibility of cord blood transplantation from sibling donors and the possibility of unrelated cord blood transplantation. A cord blood banking system is necessary for the universal use of cord blood stem cells from unrelated donors.

Anemia, Aplastic↗
PubMed1998

Establishment of a new human megakaryoblastic cell line, CMY, with chromosome 17p abnormalities.

A new megakaryoblastic cell line CMY was established from a Down's syndrome patient suffering from acute megakaryoblastic leukemia. The karyotypes of CMY showed deletion of chromosome 17 or the translocation of 17p, whereas the blasts of the patient did not reveal these abnormalities of chromosome 17 by conventional karyotype analysis. Blasts of the patient failed to respond to chemotherapy and complete remission could not be attained. The abnormalities of 17p became progressively predominant in the patient. These results suggest that the blasts of a minor clone which had the abnormalities of chromosome 17p might have existed in the patient from the beginning and CMY was established from the minor clone. Investigation of p53 gene by PCR-SSCP analysis revealed that blasts of the patient showed normal patterns, while CMY showed an abnormally migrating band in exon 5 alone. This result suggests that another novel oncogenic factor(s) besides p53 might be present on chromosome 17p and other tumor suppresser genes need to be studied.

Cell Differentiation↗
PubMed1997

Inhibition of oxidation of low-density lipoprotein by a novel antioxidant, BO-653, prepared by theoretical design.

2,3-Dihydro-5-hydroxy-2,2-dipentyl-4,6-di-tert-butyl-benzofuran (BO-653) is a novel antioxidant synthesized by theoretical designing based on the previous experimental findings and consideration. The antioxidant activities of BO-653 against the oxidative modification of low-density lipoprotein (LDL) induced by free radicals were studied. BO-653 was consumed faster than endogenous alpha-tocopherol and inhibited the formation of lipid hydroperoxides, which was observed during the consumption of alpha-tocopherol. Doxyl stearic acids incorporated into LDL as spin probes competed with the antioxidants in scavenging radicals. It was found that the efficacy of radical scavenging by alpha-tocopherol became smaller as the radical went deeper into the interior of LDL particle, whereas that by BO-653 did not change. Ascorbic acid in the aqueous phase spared alpha-tocopherol efficiently during oxidation. On the other hand, the sparing effect of ascorbic acid for BO-653 was not remarkable, unlike that for alpha-tocopherol, which implied different locations of radicals derived from BO-653 and alpha-tocopherol within the LDL particle. It was concluded that BO-653 protected LDL from oxidative modification efficiently by scavenging peroxyl radicals and by reducing alpha-tocopheroxyl radicals and that this novel antioxidant might act as a potent inhibitor of development of atherosclerosis.

Amidines↗
PubMed1997

Detection of chimeric mRNAs by reverse transcriptase-polymerase chain reaction for diagnosis and monitoring of acute leukemias with 11q23 abnormalities.

Recurrent translocations involving chromosome band 11q23 are often found in human acute leukemias. Recently, the MLL gene on 11q23 and 10 partner genes involved in these translocations have been cloned and characterized. We performed a reverse transcriptase-polymerase chain reaction (RT-PCR) to detect the resultant der(11) chimeric mRNAs of the 3 types of 11q23 translocations including t(4;11), t(9;11), or t(11;19), in 14 leukemia patients with MLL gene rearrangements. At diagnosis or relapse, chimeric mRNA could be detected in all of the 4 patients with t(4;11), 2 of 3 with t(9;11), 2 of 3 with t(11;19), and 1 of 4 with unsuccessful karyotype. In 5 patients, we could monitor minimal residual disease (MRD) serially through the clinical course. One patient, in whom chi-meric mRNA was detected during complete remission (CR) just after the induction chemotherapy, relapsed within 2 months and died, while 2 patients in which chimeric mRNA was not detected remained in CR from 10-23 months. These findings suggest that RT-PCR is a useful approach for detecting which partner gene is involved in the translocation and monitoring MRD in patients with MLL gene rearrangement. Nonetheless, the clinical relevance of MRD evaluation by RT-PCR monitoring remains controversial. Long-term and prospective investigation of a larger series of patients is needed to confirm the clinical significance of monitoring MRD by RT-PCR method.

Acute Disease↗
PubMed1997

[Treatment of acute lymphoblastic leukemia of young adults (15-22 years of age): results of co-operative study with internal medicine and pediatrics].

Ten young adults (15-22 years of age) with acute lymphoblastic leukemia were treated with the protocol of internal medicine and pediatrics co-operative study group since 1989. All patients had complete remission within 5 weeks. Four of 6 patients of low risk group (less than 30,000/microliter of WBC count at diagnosis) and 1 of 4 patients of high risk group have continued the complete remission. Three patients relapsed in bone marrow (BM), and 2 patients in both BM and central nervous system (CNS). All patients could be treated without serious complications except for infection. We obtained the good results of treatment for the low risk group, but did not for the high risk group in this study. Little is known about acute lymphoblastic leukemia in young adults because these individuals are at the borderline age between internal medicine and pediatrics. Taken together with the psychologically distinct age of these patients, it is necessary to establish a closer relationship between internal medicine and pediatrics.

Adolescent↗
PubMed1995

Expression of MDR-1/P-glycoprotein in childhood acute megakaryoblastic leukemia cells.

Multidrug resistance is a major clinical problem in chemotherapy of malignant disease. Acute megakaryoblastic leukemia (AMKL) is a rare form of childhood leukemia, and is often more resistant to many anticancer chemotherapeutic drugs compared to other types of childhood leukemia. There have been reports of the increased expression in hematologic malignancy of multidrug resistant (mdr-1) gene, which encodes for a transmembrane glycoprotein P-glycoprotein that acts as an efflux pump for structurally unrelated chemotherapeutic drugs. We investigated the malignant cells of 15 newly diagnosed childhood AMKL patients by immunocytochemical analysis and found P-glycoprotein expression in all samples from these patients. RNA prepared from five patients at the time of presentation confirmed the expression of mdr-1 specific message in all cases by Northern blot analysis. These results imply that malignant cells from all childhood AMKL might express the mdr-1/P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Treatment for B-cell-type lymphoma in a girl associated with Bloom's syndrome.

A 12-year-old girl suffering from Bloom's syndrome developed B-cell-type lymphoma in the epipharynx. She was identified as having Bloom's syndrome at the age of 3. While the tumor was eradicated completely by induction chemotherapy, the bone marrow suppression was severe and persistent. For this reason, we modified subsequent chemotherapy to a milder form. Thus the remaining therapy could be safely completed. This is the first case clearly diagnosed as having epipharyngeal B-cell-type lymphoma in the Bloom's Syndrome Registry.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

[The penetration of cefpiramide into the skin].

To investigate the skin penetration of cefpiramide (CPM, SM-1652), a broad-spectrum and long acting cephem antibiotic, 1 g of CPM was administered by single bolus intravenous injection to patients under general anesthesia during operations for full-thickness skin grafting. The CPM levels in both the serum and the skin were determined by bioassay at specified time intervals, and the following results were obtained. 1. Peak CPM concentrations in the serum (mean: 292.78 micrograms/ml) were observed 10 minutes after administration, and declined very slowly thereafter. 2. Peak CPM concentrations in the skin (mean: 23.05 micrograms/g) were observed 2 hours after administration, and then also declined very slowly. 3. The ratio of skin to serum concentrations was 16% when the peak CPM concentrations in the skin were obtained (2 hours after the administration). These results show that effective CPM concentrations were maintained in the skin for a long period, indicating a good therapeutic action against skin infections.

Adult↗
PubMed1992

[Hyperkalemia in a cyclosporine A-treated allogeneic bone marrow transplant recipient].

A 9-year-old boy was admitted with the diagnosis of myelodysplastic syndrome (FAB RAEB in T). The patient was treated with busulfan and cyclophosphamide and transplanted with bone marrow cells from an HLA identical sister. Cyclosporin A (CyA) and short term methotrexate (MTX) was given for prophylaxis against graft versus host disease (GvHD). The serum potassium value was observed to increase to 6.3 mEq/l during the period of CyA therapy. The serum potassium value returned to 4 mEq/l when CyA treatment was decreased to a serum concentration of less than 50 ng/ml (FPIA). On day 90 post transplantation the patient was diagnosed as relapsed. The patient was preconditioned with cyclophosphamide and total body irradiation and a second bone marrow transplantation was performed using cells from the same donor. He was treated again with CyA and short term MTX for the prevention of GvHD. Once again the patient became hyperkalemic with 6.8 mEq/l. The serum creatinine level was 0.9 mg/dl, the GFR was 52.1 ml/min, FEK was 7.1%. Pseudohypoaldosteronism or hyporeninemic hypoaldosteronism was suspected. To investigate this possibility a renin/aldosterone stimulation test was performed. We speculate that an idiosyncratic response to CyA resulted in pseudohypoaldosteronism and produced a defect in potassium secretion.

Bone Marrow Transplantation↗
PubMed1987

The c-sis gene expression in cells from a patient with acute megakaryoblastic leukemia and Down's syndrome.

The c-sis gene expression in leukemia cells from a patient with acute megakaryoblastic leukemia and Down's syndrome was studied. The leukemia blasts were identified as megakaryoblasts by the platelet peroxidase reaction and the reactivity against antiplatelet monoclonal antibodies. Leukemia cells obtained from peripheral blood or bone marrow specimens before and after initiation of chemotherapy were analyzed for c-sis gene expression by the RNA-DNA dot blot hybridization. Although the level varied, the mRNA of the c-sis gene was detected in all megakaryoblastic leukemia cells obtained at different clinical stages. The c-sis mRNA level in cells obtained after relapse was higher than that obtained before the initiation of therapy. The 25S c-sis mRNA was detected in a megakaryoblastic leukemia cell line established from this patient. The role of the expression of the c-sis gene in acute megakaryoblastic leukemia cells is discussed.

Acute Disease↗