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Y Komada

Publications and source records attributed to Y Komada.

At least 19 recordsLinked to original sources
PubMed1999

Comparative mechanism and toxicity of tetra- and dithiomolybdates in the removal of copper.

Tetrathiomolybdate (TTM) can be used as a specific chelator to remove copper (Cu) accumulating in the form bound to metallothionein (MT) in the livers of Wilson disease patients and Long-Evans rats with a cinnamon-like coat color (LEC rats). However, an adverse effect, hepatotoxicity, was observed occasionally on its clinical application. The mechanism underlying the adverse effect of TTM has been studied in comparison with dithiomolybdate (DTM), and a safer and more effective therapy by TTM was proposed based on the mechanism. The activity of glutamic-pyruvic transaminase (GPT) in serum was shown to increase significantly on the treatment of Wistar rats with sulfide produced through hydrolytic degradation of TTM and DTM, the latter being more easily degraded. The hydrolytic degradation of TTM was enhanced under acidic conditions. Cu in Cu-containing enzymes such as Cu,Zn-superoxide dismutase (SOD) in liver and ceruloplasmin (Cp) in plasma was decreased by excessive thiomolybdates, the Cu being found in the plasma in the form of a Cu/thiomolybdate/albumin complex. The decreased amounts of Cu in SOD and Cp were explained by the sequestration of Cu from their chaperones by thiomolybdates rather than the direct removal of Cu from the enzymes. Although both TTM and DTM remove Cu from MT, DTM is not appropriate as a therapeutic agent for Wilson disease due to its easy hydrolysis and production of sulfide.

Animals↗
PubMed1999

mRNA expression of variant Fas molecules in acute leukemia cells.

Fas (Apo-1/CD95) is a cell membrane receptor involved in apoptotic cell death. Soluble variant forms (sFas) lacking the transmembrane domain due to alternative splicing have been identified. Up-regulation of sFas expression is reportedly implicated in prereceptorial blockage of Fas-induced apoptosis in a dose-dependent manner. We examined mRNA expression of Fas and sFas in fresh leukemia cells. All leukemia cells expressed both mRNAs of full-length Fas (FasFull) and sFas with deletion of exon6 (FasDel6). The ratio of FasFull/FasDel6 mRNA expression was not always correlated with Fas-mediated growth inhibition. Interestingly, in a 6-year-old boy with acute myelogenous leukemia, blast cells obtained at onset and at the time of bone marrow relapses expressed distinct amounts of FasDel6 mRNA. Furthermore, the level of FasDel6 expression appeared to be correlated with Fas-resistance in leukemia blasts. In addition, sFas protein levels were elevated in patients' sera at onset with subsequent return to normal levels after complete remission. These results indicated that sFas could be synthesized and released by leukemia blasts and suggested that up-regulation of Fas variant transcript might render leukemia blasts resistant to Fas-mediated growth inhibition in certain cases.

Acute Disease↗
PubMed1999

Expression of homing-associated cell adhesion molecule (H-CAM/CD44) on human CD34+ hematopoietic progenitor cells.

We investigated the expression of CD44 molecule on CD34+ hematopoietic progenitor cells. Significantly lower expression of CD44 was observed on bone marrow (BM) CD34+ cells compared with circulating CD34+ cells in cord blood and peripheral blood. Using fluorescence-activated cell sorting, human CD34+ BM cells were fractionated into CD44+ and CD44- populations. Immunofluorescence analysis revealed that the majority of CD34+CD44- cells expressed B-lymphocyte-associated CD10 and CD19 antigens, whereas only a part of CD34+CD44+ cells were positive for CD19. Myeloid and erythroid progenitor cells were found predominantly in CD34+ CD44+ cell fractions. In short-term suspension cultures, cell proliferation and G1-->S transition in the cell cycle were enhanced in CD34+CD44+ cells. In contrast, a large part of CD34+CD44- cells underwent apoptotic cell death. Although co-culture with BM stromal cells could partially prevent CD34+CD44- cells from undergoing apoptosis, significant increase of apoptotic cells was consistently observed. Furthermore, CD34+CD44- cells plated on BM stromal cells could differentiate into CD34-CD44-CD10-CD19+ cells. These findings suggest that CD34+CD44- cells expressing CD19 would represent unique B-lymphocyte-committed precursors in BM, which might undergo apoptotic cell death in the early steps of B-cell differentiation.

Adult↗
PubMed1999

A randomised dose-comparison trial of granisetron in preventing emesis in children with leukaemia receiving emetogenic chemotherapy.

This randomised study was performed to assess the anti-emetic efficacy and tolerability of two-dose regimens of granisetron in children with leukaemia. 49 children with leukaemia were treated with three consecutive courses of high-dose methotrexate or cytarabine regimen. During the first course, patients were evaluated regarding the emetogenicity of each regimen. They were randomised in a crossover manner to receive 20 or 40 micrograms/kg of granisetron before the second and third course of chemotherapy. Neither emesis nor severe appetite loss were observed in over 80% of patients within the first 24 h in all treatment groups. There was no significant difference in the anti-emetic efficacy between the two-dose regimens of granisetron. However, complete protection was achieved less frequently on days 2 and 3. Older children and girls appeared to be less well protected. No adverse events attributable to granisetron were observed. Granisetron dose regimens of 20 and 40 micrograms/kg are, comparably, well tolerated and effective in controlling chemotherapy-induced emesis in the first 24 h, though this protection fails thereafter, particularly in older patients and girls.

Adolescent↗
PubMed1999

Human dendritic cells express the thrombopoietin receptor, c-Mpl.

Human thrombopoietin (TPO) is a haemopoietic growth factor that is essential for the growth and development of megakaryocytes. However, c-Mpl, the TPO receptor, has been detected in human leukaemic cell lines with a myelomonocytic phenotype. These results raise the possibility that dendritic cells (DC), a putative myeloid lineage cell, may also express c-Mpl and respond to TPO. In haemopoietic stem cell transplantation, DC could induce graft-versus-host disease by its strong antigen-presenting capacity. In this study we have examined the effect of TPO on differentiation and the antigen-presenting capacity of DC. To differentiate DC, cord blood CD34+ cells were cultured in the presence of a cytokine cocktail either in serum-free medium or RPMI1640 containing 10% fetal bovine serum. Flow cytometric analysis and immunocytochemical staining demonstrated that c-Mpl was expressed on DC. Furthermore, the expression of c-Mpl mRNA was detected in DC by RNase protection assay. However, when TPO was added to the culture system there were no significant changes in the differentiation and mixed leucocyte-stimulating capacity of DC. These findings suggest that TPO may be administered following cord blood transplantation without significant augmentation of antigen presentation mediated by DC.

Cell Division↗
PubMed1999

Possible involvement of bcl-2 in regulation of cell-cycle progression of haemopoietic cells by transforming growth factor-beta1.

Transforming growth factor-beta1 (TGF-beta1) acts directly on haemopoietic progenitor cells to regulate their growth. To investigate a possible link between the action of TGF-beta1 and cell death regulators such as bcl-2, we utilized Ba/F3 cells, the interleukin-3 (IL-3)-dependent growth of which could be modulated by TGF-beta1, as well as haemopoietic progenitor cells. We demonstrate here that up-regulation of bcl-2 protein (Bcl-2) as well as that of an inhibitor of cyclin/cyclin-dependent kinase complex, p27, was associated with TGF-beta1-induced deceleration of the cell-cycling of haemopoietic progenitor cells and Ba/F3 cells. The data from cell-cycle analysis of Ba/F3 cells showed that TGF-beta1 retarded the G1 to S phase transition. Analysis of cells with the potential to express Bcl-2 in an inducible manner indicated that up-regulation of Bcl-2 was sufficient for not only an increase in the level of p27 but also to inhibit the cell growth. Using c-kit-overexpressing cells, we observed that the potential of TGF-beta1 to up-regulate the expression of Bcl-2 and p27 could be counteracted by the c-kit ligand, stem cell factor. These results demonstrate that Bcl-2 exerts an essential function in the regulation of G1 to S phase transition of haemopoietic cells by TGF-beta1.

Animals↗
PubMed1999

[Smooth muscle myosin of SM1 and SM2 isoforms expressing human neuroblastoma cell line of MP-N-MS].

Human neuroblastoma (NB) cell lines have at least three morphological appearance of neuroblastic (N-type), substrate-adhessive (S-type) and intermediate(I) cells. Our previous study revealed S-type cells expressed alpha-smooth muscle actin, desmin and/or basic-calponin, indicating the plausible smooth muscle cell characteristics of S-type cells. In this study, a new human NB cell line, MP-N-MS, was established from bone marrow metastasis of a one year and six-month old girl with advanced NB, originating from right adrenal gland. Morphology of this cell line is composed of S-type cells. MP-N-MS was identified as a NB cell line by surface membrane antigen analysis and MYCN gene amplification. EWS-FLI1 and EWS-ERG chimeric products, observed in Ewing family tumors, were not detected by RT-PCR (reverse transcriptase-polymerase chain reaction). In cytoskeletal protein analysis, alpha-smooth muscle actin and basic calponin of smooth muscle cell markers were detected. Furthermore, smooth myosin of SM1 isoform was identified in MP-N-MS cell line by immunofluorescence, Western blot and RT-PCR, whereas smooth myosin of SM2 was detected by RT-PCR. MP-N-MS is the first cell line, showing SM1 and SM2 isoforms. The presence of smooth muscle myosin of SM1 and SM2 isoforms in MP-N-MS demonstrated the mature smooth muscle phenotype of this NB cell line, and the ability of NB cells to differentiate into smooth muscle cell.

Cell Differentiation↗
PubMed1998

Down-regulation of Fas-associated phosphatase-1 (FAP-1) in interleukin-2-activated T cells.

Peripheral T cells are resistant to Fas receptor (FasR/CD95)-mediated apoptosis. After prolonged treatment with interleukin-2 (IL-2), these T cells develop a Fas-sensitive phenotype. To clarify the molecular mechanism of apoptosis susceptibility, mRNA expression of FasR-associated proteins [Fas-associating protein with death domain (FADD), receptor-interacting protein (RIP), and Fas-associated phosphatase-1 (FAP-1)] has been investigated in IL-2 activated T cells. Competitive reverse transcriptase-polymerase chain reaction analysis revealed that FADD and RIP mRNA were equally expressed in freshly isolated resting T cells and IL-2-activated T cells. In contrast, FAP-1 mRNA was produced more abundantly by Fas-resistant resting T cells than by Fas-sensitive activated T cells. These findings suggested that sensitivity to FasR-mediated apoptosis in T cells could be correlated with down-regulation of FAP-1 expression. Additionally, CD45RO+ memory T cells expressed a larger amount of FAP-1 mRNA than did CD45RA+ naive T cells.

Adaptor Proteins, Signal Transducing↗
PubMed1998

CD4+ and CD8+ cell cytokine profiles in neonates, older children, and adults: increasing T helper type 1 and T cytotoxic type 1 cell populations with age.

The growing body of evidence suggestive of T helper types 1 and 2 (Th1/Th2) including their counterparts T cytotoxic types 1 and 2 (Tc1/Tc2) cell responses during various human disease states necessitates determination of normal T cell subsets' cytokine profiles. We show here, using intracellular cytokine staining and flow cytometry, that in healthy subjects interferon (IFN)-gamma producing CD4+ (Th1) and CD8+ (Tc1) cell populations progressively increase with age with strong correlation to CD45RO surface antigen expression. Meanwhile populations of cells capable of producing IL-4 (Th2 and Tc2) are comparably minimal across all age groups. Collectively, these results may reflect the maturation and expansion of Th1 and Tc1 cell populations from the neonatal period to adulthood, most probably dependent on antigen exposure.

Adolescent↗
PubMed1998

Flow cytometric analysis of peripheral blood and bone marrow for tumor cells in patients with neuroblastoma.

BACKGROUND: Several sensitive surveillance tests reportedly have been used to detect occult neuroblastoma (NB) cells in peripheral blood (PB) and bone marrow (BM). They may be useful in monitoring minimal residual tumor cells. The authors report the feasibility and clinical usefulness of a sensitive flow cytometric assay that has been newly developed and evaluated to detect NB cells. METHODS: Nine NB patients and 15 healthy donors were included in the current study. Primary tumor tissues, BM, and PB were examined for the detection of NB cells using a triple-color flow cytometric assay. Tumor cells in PB and BM, isolated by fluorescence-activated cell sorting, were used for morphologic studies and differential polymerase chain reaction analysis of N-myc gene amplification. RESULTS: Neuroblastoma cells consistently showed CD9+/CD56+/CD45- phenotype. Flow cytometric analysis could detect NB cells at a level of 1 per 10(4-5) cells. The CD9+/CD56+/CD45- cell population was absent in normal PB and BM. This assay identified occult NB cells, which were not detected by conventional cytology, in PB and BM obtained from six patients (one of two with Stage II and all five with advanced disease) at diagnosis. Residual NB cells also were detected in PB and BM during therapy. Neuroblast-like morphology and N-myc gene amplification of sorted cells confirmed that CD9+/CD56+/CD45- cells were truly NB cells. CONCLUSIONS: A triple-color flow cytometric assay was a sensitive and specific method to detect occult NB cells in PB and BM. This assay could be an additional component of surveillance testing for NB patients.

Antigens, CD↗
PubMed1998

Thymic B-cell non-Hodgkin's lymphoma in a child.

A 13-year-old male developed thymic non-Hodgkin's lymphoma. Microscopically, the tumor was composed of large cells, resembling centroblasts. Immunohistochemically, the tumor demonstrated leukocyte common antigen+, L26 (B-cell)+, UCHL1 (T-cell)-, suggesting the B-cell phenotype. In contrast to the terminally differentiated phenotype (CD10-, surface immunoglobulin-) observed in adult cases, flow cytometric analysis showed that they were relatively immature: CD10+, CD19+, HLA-DR-, IgM+/-, kappa+. He was successfully treated with intensive chemotherapy. Since childhood thymic lymphomas are exclusively small non-cleaved cell lymphoma with T-cell phenotype, this case represents a unique entity in children.

Adolescent↗
PubMed1998

Thrombopoietin level is inversely related to blast count, not platelet number, in Down syndrome neonates with transient myeloproliferative disorder.

Transient myeloproliferative disorder (TMD) in neonates with Down syndrome is characterized by increased megakaryoblastic cells in the peripheral blood. Despite their spontaneous regression in weeks, prognosis is not always favorable because of fatal hepatic fibrosis. In this study, blood thrombopoietin (TPO) levels were measured by ELISA in six TMD patients and the expression of c-Mpl, a ligand for TPO, was examined on the blast cells from four patients by flow cytometer. At the onset, TPO level was undetectable in one patient and significantly lower in five patients than six neonatal controls (mean 0.52 fmol/ml, range 0.30-0.93 vs. 3.70, 1.38-8.33, P < 0.001), although platelet counts were similar (mean 321 x 10(9)/l, range 42-1,040 vs. 253 x 10(9)/l, 124-381). Two patients died of hepatic failure. TPO levels were measured in five patients after regression of the blast cells. With regression of blast cells, TPO levels were remarkably increased in four survived patients. In one patient with hepatic failure, TPO level was poorly elevated and relatively lower compared to the others. TPO levels were inversely correlated with blast numbers (r = -0.85, P < 0.001), but not with platelet counts (r = 0.426). Blast cells from four patients were all positive for c-Mpl. Our findings suggest that megakaryocyte mass is a major regulator of TPO levels and hepatic failure may affect the TPO level because liver is a major source of TPO production.

Cell Count↗
PubMed1998

CD4+ T-lymphocytopenia in long-term survivors following intensive chemotherapy in childhood cancers.

BACKGROUND: It is generally believed the effects of short intensive courses of therapy are rapidly reversible in childhood cancers, and immunologic function following years of maintenance treatment with chemotherapy usually returns to normal by 6 months or less when treatment is terminated. However, we previously demonstrated that dysregulation of immunoglobulins, especially IgD, was observed in long-term survivors following intensive chemotherapy in cancer patients. With regard to cellular immunity, investigators reported that antineoplastic chemotherapy significantly reduces the number of CD4+ T-lymphocytes, and production of newly developing CD4+ T-lymphocytes was inversely related to the patients' age. However, the incidence of CD4+ lymphocytopenia in long-term survivors of childhood cancers is not known. PROCEDURE: Here, we report the flow cytometric analysis of peripheral blood from long-term survivors who continue complete remission off chemotherapy for more than 5 years. RESULTS: Six out of 74 long-term survivors (8.1%), showed low CD4+ T-lymphocyte count (<300/mm3). Three of six patients showed continued CD4+ T-lymphocytopenia over a year. In spite of the persistent low levels of CD4+ T cells, these three patients were not susceptible to severe infections. COMMENT: Intriguingly, in patients with CD4+ T-lymphocytopenia there has been a tendency toward increased numbers of natural killer cells or gamma delta T cells that may be operating as a thymus-independent compensatory mechanism to defend the hosts.

Adolescent↗
PubMed1998

Suppression of alloreactivity with gamma delta T-cells: relevance to increased gamma delta T-cells following bone marrow transplantation.

Several reports have shown that an increase in T-cell receptor gamma/delta-positive T-cells (gamma delta T-cells) have been observed following bone marrow transplantation. gamma delta T-cells expanded from peripheral blood mononuclear cells from normal volunteers were used to investigate the function of gamma delta T-cells in vitro. Peripheral blood mononuclear cells were cultured with synthetic ligand of gamma delta T-cells, monoethyl phosphates (MEP), for 7 days. MEP specifically expanded gamma delta T-cells. Expanded gamma delta T-cells from subject "B" were added to an A anti-B or A anti-C mixed lymphocyte culture (MLC) containing responder cells from subject "A" and irradiated stimulator cells from subjects "B" or "C". The cultures were harvested on day 6 and tested for cytotoxicity against stimulator-type Con A blasts. gamma delta T-cells from subject "B" specifically inhibit generation of allospecific cytotoxic T lymphocytes (CTL) in A anti-B MLC. The results indicate that gamma delta T-cells exhibit veto-type suppression of alloreaction. If the current experiments are also applicable in vivo, gamma delta T-cells originating from the donor after bone marrow transplantation may inhibit graft rejection by suppressing recipient anti-donor reactivity. gamma delta T-cells may be involved in the suppression of allogeneic reaction in vivo following allogeneic bone marrow transplantation.

Bone Marrow Transplantation↗
PubMed1998

Late-onset unilateral renal dysfunction combined with non-insulin-dependent diabetes mellitus and bronchial asthma following allogeneic bone marrow transplantation for acute lymphoblastic leukemia in a child.

We report a child with T cell acute lymphoblastic leukemia who developed late-onset multiple complications after allogeneic bone marrow transplantation from an HLA-matched sibling. The preparative regimen consisted of total body irradiation (TBI, 12 Gy), splenic irradiation (6 Gy) and cytosine arabinoside (3 g/m2 x 10). Splenic irradiation was added because of persistent splenomegaly in spite of intensive chemotherapy. He developed bronchial asthma 1 1/2 years post transplant. He presented with microhematuria and proteinuria 4 1/2 years post-transplant, which were due to unilateral left renal dysfunction. He developed type II, non-insulin-dependent diabetes mellitus 8 years post-transplant. A biopsy from the left kidney was not compatible with diabetic nephropathy. All these complications appear to be independently related to BMT, particularly TBI and/or splenic irradiation.

Adolescent↗
PubMed1998

Cytokine-enhanced mixed lymphocyte reaction (MLR) in cord blood.

Although in cord blood (CB) transplantation graft-versus-host disease (GVHD) is reported to be less severe, GVHD may occur even in patients with HLA-identical sibling donors. This result shows that HLA typing can not entirely predict GVHD. The standard MLR with CB cells was either normal or slightly reduced compared with adult peripheral blood (PB) cells. We used two manipulations to increase the responses of CB cells to allo-antigens. The first was to treat the stimulator cells with cytokines, and the second to amplify weak proliferative responses by adding exogenous cytokines to MLR cultures (modified MLR). The stimulator cells were treated with both interferon-gamma (IFN-gamma) and IL-4. The responder cells were treated with both IL-2 and tumour necrosis factor-alpha (TNF-alpha). It is still to be determined whether or not this cytokine-enhanced MLR could be a possible predictor of GVHD. However, using these cytokines, 90% of CB could recognize allo-antigens, even if the standard MLR was negative.

Adult↗
PubMed1998

Surface marker patterns of T cells and expression of interleukin-2 receptor in measles infection.

The surface marker patterns of T cells of Ghanaian children during measles infection were studied and an attempt was made to demonstrate T cell activation and viability in vitro after activation in vivo by measles virus. The frequencies of CD4+ and CD8+ naive T cells in measles patients were high while their memory T cells were remarkably reduced with no sign of proliferation even at the acute phase of the illness. The reduction of memory T cells was prolonged during the convalescent phase (2 months after onset). The anti-CD3 monoclonal antibody-induced expression of interleukin-2 receptor alpha chain (IL-2R/CD25) was significantly suppressed; however, the addition of phorbol 12-myristate 13-acetate or ionomycin caused a remarkable recovery of CD25 expression. On simple culture, an appreciable proportion of T cells from measles patients died rapidly in contrast with only a few T cells from healthy controls doing so. The suppression of CD25 expression was still demonstrated during the convalescent phase of the disease. Taken together these results suggest unresponsiveness and activation-induced cell death of T cells during severe measles infection in Ghanaian children. Furthermore the prolonged abnormalities of T cells (i.e. decreased memory T cells and inhibition of CD25 expression during the convalescent phase) might be related to post-measles infection immunosuppressive status.

Antigens, Surface↗