Search PubMed⌕ Search

Biomedical subjects

H Mizoguchi

Publications and source records attributed to H Mizoguchi.

At least 127 records · Page 7Linked to original sources
PubMed1998

Transcription factor NF-E2 is essential for the polyploidization of a human megakaryoblastic cell line, Meg-J.

Transcription factors regulating the process of megakaryocyte development remain largely unclarified. To clarify them further, we used a human megakaryoblastic cell line, Meg-J, which showed prominant polyploidization and augmented platelet glycoprotein (GP) Ib expression after incubation with thrombopoietin (TPO, c-mpl ligand) and K252a (an indolocarbasole derivative). Under these conditions, we analyzed the expression of the transcription factors and observed that the expression of NF-E2 p45, but not those of GATA-1, GATA-2, Tal-1/SCL, Evi-1, and MafK, was increased after TPO and K252a stimulation. Gel-shift assay confirmed the enhanced binding activity to the NF-E2 site. The abolishment of NF-E2 p45 with NF-E2 antisense oligomers inhibited TPO plus K252a-induced polyploidization. These findings suggest that NF-E2 p45 is essential for the polyploidization of megakaryocytic cells.

Basic Helix-Loop-Helix Proteins↗
PubMed1998

Inhibition of P-glycoprotein and recovery of drug sensitivity of human acute leukemic blast cells by multidrug resistance gene (mdr1) antisense oligonucleotides.

To overcome the problem of multidrug resistance, we investigated the effectiveness of phosphrothioate antisense oligonucleotides (MDR1-AS) in suppressing multidrug resistance gene (mdr1) expression in drug-resistant acute myelogenous leukemia (AML) blast cells and the K562 adriamycin-resistant cell line K562/ADM. The percentage of cells with the mdr1 gene product P-glycoprotein (P-gp) was decreased from 100% to 26% by 20 micromol/L MDR1-AS in the K562/ADM cells, and from 48.1% to 10.2% by 2.5 micromol/L MDR1-AS in the AML blast cells. Western blot analysis also showed a decrease in the amount of P-gp in the MDR1-AS-treated K562/ADM cells. This effect was specific to MDR1-AS, and not observed with sense or random control oligonucleotides. The expression of mdr1 mRNA in K562/ADM and AML blast cells treated with MDR1-AS was decreased compared with the random control. Intracellular rhodamine retention and [3H]daunorubicin also increased after antisense treatment. Chemosensitivity to daunorubicin increased in MDR1-AS-treated blast cells up to 5.9-fold in the K562/ADM cells and 3.0- to 6.4-fold in the AML blast cells. The expression of mdr1 mRNA derived from colony cells decreased in the MDR1-AS-treated groups. No inhibitory effect of the oligonucleotides on normal bone marrow progenitors was observed. These findings suggest that MDR1-AS is useful to overcome multidrug resistance in the treatment of leukemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Large granular lymphocyte leukemia with pure red cell aplasia in a renal transplant recipient.

Neoplastic disorders sometimes accompany a renal transplant. Herein, we report a large granular lymphocyte (LGL) leukemia patient with pure red cell aplasia (PRCA) after renal transplantation. A 36-year-old female was presented to our department with anemia in February 1996. She had undergone hemodialysis because of pregnancy in December 1981. She received a renal transplantation from her mother in April 1986. After the transplantation, she received cyclosporin A (CyA) at 2 mg/kg/day, mizoribine at 1 mg/kg/day, and methylprednisolone at 0.1 mg/kg/day for 8 years. In July 1995, her hemoglobin level dropped to 9.3 g/dl, and anemia developed gradually. In January 1996, her hemoglobin was 5.8 g/dl, and she was given a red blood cell transfusion. Laboratory findings were as follows: RBC 1.46 x 10(12)/L; hemoglobin 5.8 g/dl; hematocrit 17.8%; leucocytes 5.2 x 10(9)/L with 62.4% neutrophils, 34.1% lymphocytes, 2.6% monocytes; platelets 50.8 x 10(10)/L; reticulocytes 0.4%. Bone marrow aspirate smears and biopsy sections revealed normal myeloid and megakaryocyte differentiation with few erythroid precursors. The lymphocytes were of medium size with granules in the cytoplasm. More than 90% of lymphocytes were of the LGL type. Surface markers of peripheral blood mononuclear cells demonstrated increases in the CD2+, CD3+, CD4-, and CD8+ populations. A monoclonal rearrangement of T-cell receptor (TCR)-beta chain gene was found by Southern blot analysis of the mononuclear cells in peripheral blood. A diagnosis of LGL leukemia with PRCA was made. During the next 4 months, she received six red blood cell transfusions, a total of 12 U. In March 1996, the patient was treated with cyclophosphamide (1 mg/kg/day). After 1 month of treatment, serum GPT levels increased to 60 IU/l. The dose of cyclophosphamide was reduced to 0.5 mg/kg/day. Two months after initiation of the therapy, the patient developed reticulocytosis and blood transfusion was not needed thereafter. During remission, the number of CD2+, CD3+, CD4-, and CD8+ lymphocytes decreased. Large granular lymphocytes decreased to less than 10% of peripheral blood. The monoclonal rearrangement of the TCR-beta chain gene in peripheral blood disappeared.

Adult↗
PubMed1998

Clinical and cytogenetic remission induced by interferon-alpha in a patient with chronic eosinophilic leukemia associated with a unique t(3;9;5) translocation.

A patient with chronic eosinophilic leukemia and a unique complex chromosomal translocation 46,XY,t(3;9;5)(q25;q34;q33) who had elevated blood interleukin-5 is reported. Complete cytogenetic remission was induced by interferon-alpha after treatment failure with corticosteroids and cytotoxic drugs. Severe cardiopulmonary symptoms due to hypereosinophilia and thromboembolic complication improved dramatically in the first 6 months of interferon therapy. Since it is known that the gene encoding for interleukin-5 resides on the long arm of chromosome 5, it may be possible that the chromosomal translocation in our patient resulted in overproduction of this cytokine, and our findings may be helpful for understanding the pathogenesis of this disorder.

Adult↗
PubMed1998

Down-regulation of telomerase activity is an early event of cellular differentiation without apparent telomeric DNA change.

With the use of three different hematopoietic cell lineages, the downregulation of telomerase activity was found to be a general response to the induction of differentiation. The decrease in telomerase activity occurred as early as 24 h when HL-60 and K562 cells were cultured in the presence of 1alpha, 25 dihydroxyvitamin D3 (VD3), all-trans-retinoic acid (ATRA) and hemin, and completely disappeared after 3 days. On the other hand, MEG-01 cells showed a marked inhibition of telomerase activity after 6 days of culture with 12-0-tetradecanoylphorbal 13-acetate (TPA). The analysis of telomeric DNA in the HL-60 cells and K562 cells demonstrated no detectable loss of telomeric DNA with cellular differentiation, with a loss of telomerase activity. The repression of telomerase is a common molecular event during leukemic cell differentiation.

Base Sequence↗
PubMed1998

A long term follow-up of a randomized trial comparing interferon-alpha with busulfan for chronic myelogenous leukemia. The Kouseisho Leukemia Study Group.

To evaluate the long-term effectiveness of interferon-alpha (IFN-alpha) therapy in patients with chronic myelogenous leukemia (CML) in chronic phase, we examined the updated outcomes of 159 patients who had been enrolled between 1988 and 1991 into a randomized trial comparing IFN-alpha with busulfan. At a median follow-up of 73 months, the median survival was 71 months in the IFN-alpha group and 55 months in the busulfan group (P=0.0563), and the median time of remaining in chronic phase was 58 months in the IFN-alpha group and 39 months in the busulfan group (P=0.4676). Landmark analysis showed a significant advantage in survival (P=0.009) and duration of chronic phase (P=0.0001) in patients with any cytogenetic response among the IFN-alpha group. About half patients were discontinued IFN-alpha administration in spite of cytogenetic response in this study. It appears that continuation of IFN-alpha might possibly confer a survival advantage. Pretreatment factors associated with cytogenetic response included high hemoglobin level, low percentage of peripheral basophils and low leukocyte counts. Multivariate analysis identified lower percentage of bone marrow basophilia (P=0.007) for survival advantage. If a group with a very good prognosis is predicted by a new prognostic model, it might be an option to wait for bone marrow transplantation.

Adult↗
PubMed1998

Pregnancy among long-term survivors of acute leukemia. A second nationwide survey.

A second nationwide survey was conducted to determine the outcome of pregnancy in long-term survivors of acute leukemia and to clarify the influence of treatment on the offspring of long-term survivors. In July 1996, 336 survey responses were received from the 498 Japanese institutions surveyed. A total of 89 cases (39 spouses of male patients and 50 female patients) who had babies during their first remission were analyzed, including 43 patients from the first survey in 1991. Median age at the birth of first baby was 30.7 years for male patients and 28.6 years for female patients. A total of 109 of the 117 pregnancies resulted in live births and eight resulted in abortions. A total of 58 cases had single children and 23 cases had two or more, generally from separate pregnancies, but including two pairs of twins. The infant was male in 59 cases, female in 37 and gender was not reported in 13 cases. Ages of children ranged from 2 months to 20 years at the time of this study and all children were in good health. There were two minor anomalies, both of which were surgically corrected. Of the 81 parents bearing live infants, 75 remained in complete remission. Five fathers died (four of relapse and one of another disease). In conclusion, there was no apparent increase in pregnancy complications or congenital anomalies in the children of long-term survivors with acute leukemia.

Acute Disease↗
PubMed1998

Dual action of CD30 antigen: anti-CD30 antibody induced apoptosis and interleukin-8 secretion in Ki-1 lymphoma cells.

CD30 is a member of the tumor necrosis factor superfamily. In this study, we examined the effect of four anti-CD30 (aCD30) antibodies (Abs) on CD30-positive anaplastic large cell lymphoma-derived cell line, Ki-JK. The aCD30 Abs suppressed [3H]thymidine (TdR) incorporation. With a TdT mediated dUTP-biotin nick end labeling method, apoptosis was detected in Ki-JK cells at day 5 after the addition of aCD30 Ab to the culture. Genistein, an inhibitor of protein tyrosine kinase, had no effect on aCD30 Ab-induced apoptosis. The aCD30 Ab simultaneously induced interleukin-8 (IL-8) secretion in the Ki-JK cells. In culture of the Ki-JK cells with aCD30 Ab for 5 days, the IL-8 concentration of the cell free-supernatant increased to 240 +/- 16 pg/ml, though the concentration was < 12.5 pg/ml without aCD30 Ab. In combination with aCD30 Ab, genistein decreased the concentration of IL-8 in day 5 supernatants. Although, doxorubicin and herbimycin-A suppressed [3H]TdR incorporation and induced apoptosis in the Ki-JK cells, they did not induce IL-8 secretion. Only aCD30 Ab-induced apoptosis was accompanied by IL-8 secretion. IL-8 mRNA was not detected in the Ki-JK cells by reverse transcription-polymerase chain reaction assay. IL-8 mRNA was detected 5 days after adding aCD30 Ab to the culture.

Antibodies↗
PubMed1998

Changes of telomere length in children after hematopoietic stem cell transplantation.

Telomeres are responsible for keeping the stability not only of chromosomes but also of genes. To investigate the effect of hematopoietic stem cell transplantation (HSCT) on telomeres, we studied telomere length in the peripheral blood mononuclear cells of 31 children who received HSCT. In the auto-HSCT groups telomere length ranged from 8.6 to 12.0 kb and in the allo-HSCT groups from 8.4 to 12.0 kb. Comparison of the telomere length between before and after auto-HSCT showed shorting up to 1.0 kb. Moreover, comparison between donors and recipients in allo-HSCT revealed that telomeres of recipients were up to 1.0 kb shorter than those of the donors. Patients who received allo-HSCT from donors older than 18 years had significantly shorter telomeres than those transplanted from donors under 18 years old (P < 0.05), indicating that donor age is an important factor for recipient's telomere length. These findings suggest that the effects which might be induced by shortening of telomeres in recipients are within the biologically tolerable range. However, if hematopoietic stem cells from elderly donors are transplanted into younger patients, the telomere length may become too short for acceptable lifetime risks of genetic instability in the recipient.

Adolescent↗
PubMed1998

Clonal T-cell proliferation causing pure red cell aplasia in chronic B-cell lymphocytic leukaemia: successful treatment with cyclosporine following in vitro abrogation of erythroid colony-suppressing activity.

Clonal T cells that cause pure red cell aplasia were demonstrated in a patient with chronic B-cell lymphocytic leukaemia. The T-cell fraction was enriched by the immunomagnetic method and shown to have T-cell receptor-beta gene rearrangement. Cryopreserved T cells, obtained during the period of anaemia, suppressed autologous erythroid progenitor cell growth from remission marrow. The colony-suppressing activity was markedly improved by the addition of cyclosporine to the culture medium. The patient achieved haematological remission by cyclosporine monotherapy. Cyclosporine treatment may improve erythropoiesis in both a T-cell-dependent and a T-cell-independent manner.

Blotting, Southern↗
PubMed1998

K-252a-induced polyploidization and differentiation of a human megakaryocytic cell line, Meg-J: transient elevation and subsequent suppression of cyclin B1 and cdc2 expression in the process of polyploidization.

Megakaryocytes are unique haemopoietic cells which undergo DNA replication, giving rise to polyploid cells. However, little is known about the mechanism of megakaryocytic polyploidization. To address this issue, we used the human megakaryocytic cell line Meg-J. In the presence of K-252a (an indolocarbasole derivative), Meg-J cells stopped proliferation and exhibited additional megakaryocytic features, including morphological changes, polyploidization, and increases in the levels of surface expression of platelet glycoprotein (GP) IIb/IIa and GPIb. Thrombopoietin (TPO) promoted the K-2 52a-induced polyploidization and megakaryocytic differentiation. In the process of K-252a-induced polyploidization, levels of expression of both cdc2 and cyclin B1 were elevated transiently and subsequently decreased. This suggested that the polyploidization process in Meg-J cells was at least in part associated with a transient elevation and subsequent decrease in the expression of cdc2/cyclin B1 complex, a critical kinase involved in G2/M cell cycle transition.

CDC2 Protein Kinase↗
PubMed1998

Arsenic induces apoptosis in B-cell leukaemic cell lines in vitro: activation of caspases and down-regulation of Bcl-2 protein.

We showed that arsenic inhibited the cell growth of four B-cell leukaemia cell lines of 11 various cell lines in vitro. In two of these four lines, KOCL44 and LyH7, apoptosis was identified by morphological and nucleosomal DNA fragmentation studies. Three of the four B-cell lines that were growth inhibited were acute infantile leukaemia with t(11;19)(q23;p13) translocations involving the MLL gene that encodes the transcriptional factor Drosophila trithorax. The arsenic-induced apoptosis in KOCL44 and LyH7 cells was found to be linked to caspases by Western blot and enzymological analyses. The amount of Bcl-2 was reduced during apoptosis in LyH7 as judged by Western blot analysis. We concluded that combined activation of the caspases and down-regulation of Bcl-2 could determine the fate of B-cell leukaemic cells in response to arsenic.

Animals↗
PubMed1998

Growth, pigmentation, and expression of the puf and puc operons in a light-responding-repressor (SPB)-disrupted Rhodobacter sphaeroides.

We previously cloned a trans-repressor, SPB, for the puf operon of Rhodobacter sphaeroides (Shimada et al. 1996) and revealed that SPB was a putative genetic counterpart to HvrA in Rhodobacter capsulatus, a trans-activator for the puf and puh operons (Mizoguchi et al. 1997). In this study we constructed a spb-disrupted R. sphaeroides, strain L-7, to elucidate the function of SPB. This disruption of the spb gene increased the photosynthetic growth rate and the cellular levels of photopigments under low-intensity light conditions. The disruption also derepressed the expression of the puf and puc operons under high-intensity light conditions. In strain L-7, however, strong illumination still reduced the cellular levels of photopigments as it did in the wild strain, suggesting that SPB did not directly affect the formation of photopigments. These results support our previous suggestion that SPB functions as a high-light repressor for puf operon in R. sphaeroides in striking contrast to HvrA, which is a low-light activator for puf and puh operons in R. capsulatus, even though SPB and HvrA are highly homologous. Disruption of spb gene had no effect on the oxygen-mediated regulation of the pigmentation or the expression of puf and puc operons.

Bacterial Proteins↗
PubMed1998

Diversity in protein synthesis and viability of Helicobacter pylori coccoid forms in response to various stimuli.

The viability of the coccoid forms of Helicobacter pylori was evaluated by assessing protein synthesis. Metabolic labeling studies showed the synthesis of proteins and the specific protein profiles of H. pylori coccoids produced under various conditions. Harsh conditions such as aerobiosis and starvation (lack of horse serum) in the culture did not affect the synthesis of proteins in the coccoids. Lowering of the pH to that of gastric secretions induced expression of several proteins in the coccoids. However, the coccoids produced under prolonged microaerobic conditions exhibited a profile of acid stress-induced protein expression different from that induced by aerobiosis or starvation. Our data suggest that coccoid H. pylori exhibits diversity in viability following exposure to different stresses and that the response to acid stress of coccoid H. pylori could be involved in infection of the host stomach.

Acids↗
PubMed1998

Cyclooxygenase-2 selective and nitric oxide-releasing nonsteroidal anti-inflammatory drugs and gastric mucosal responses.

Occurrence of gastrointestinal damage and delayed healing of pre-existing ulcer are commonly observed in association with clinical use of nonsteroidal antiinflammatory drugs (NSAIDs). We examined the effects of NS-398, the cyclooxygenase (COX)-2 selective inhibitor, and nitric oxide (NO)- releasing aspirin (NCX-4016) on gastric mucosal ulcerogenic and healing responses in experimental animals, in comparison with those of nonselective COX inhibitors such as indomethacin and aspirin. Indomethacin and aspirin given orally were ulcerogenic by themselves in rat stomachs, while either NS-398 or NCX-4016 was not ulcerogenic at the doses which exert the equipotent antiinflammatory action with indomethacin or aspirin. Among these NSAIDs, only NCX-4016 showed a dose-dependent protection against gastric lesions induced by HCl/ethanol in rats. On the other hand, the healing of gastric ulcers induced in mice by thermal-cauterization was significantly delayed by repeated administration of these NSAIDs for more than 7 days, except NCX-4016. Gastric mucosal prostaglandin contents were reduced by indomethacin, aspirin and NCX-4016 in both normal and ulcerated mucosa, while NS-398 significantly decreased prostaglandin generation only in the ulcerated mucosa. Oral administration of NCX-4016 in pylorus-ligated rats and mice increased the levels of NO metabolites in the gastric contents. In addition, both NS-398 and NCX-4016 showed an equipotent anti-inflammatory effect against carrageenan-induced paw edema in rats as compared with indomethacin and aspirin. These results suggest that both indomethacin and aspirin are ulcerogenic by themselves and impair the healing of pre-existing gastric ulcers as well. The former action is due to inhibition of COX-1, while the latter effect may be accounted for by inhibition of COX-2 and mimicked by NS-398, the COX-2 selective NSAID. NCX-4016, despite inhibiting both COX-1 and COX-2, protects the stomach against damage and preserves the healing response of gastric ulcers, probably because of the beneficial action of NO.

Animals↗
PubMed1998

[Telomere and telomerase in the differentiation of leukemic cell lines].

By using three hematopoietic cell lineages including myelomonocytic, erythroblastic and megakaryocytic differentiation, downregulation of telomerase activity was found to be a general response to the induction of differentiation. The decrease in telomerase activity occurred as early as 24h when HL-60 and K562 cells were cultured in the presence of VD3, ATRA and hemin and completely disappeared after 3 days. On the other hand MEG-01 cells showed dramatic inhibition of telomerase activity after 6 days of culture with TPA. Analysis of telomeric DNA in HL-60 cells and K562 cells demonstrated no remarkable loss of telomeric DNA with cellular differentiation while loosing telomerase activity. The repression of telomerase is one of many molecular events during the complex process of cellular differentiation, and testing of additional cell lines that are capable of differentiation will be helpful for understanding the mechanisms of telomerase control.

HL-60 Cells↗
PubMed1998

All-trans retinoic acid modulates Fas antigen expression and affects cell proliferation and apoptosis in combination with anti-Fas monoclonal antibody in the human myeloma cell line, U266B1.

All-trans retinoic acid (ATRA) is a vitamin A derivative that induces the differentiation of myeloid leukemia cells in vitro and in vivo. Several investigators have recently reported that ATRA downregulates the production of interleukin-6 (IL-6) and the expression of IL-6 receptor (IL-6R) and also inhibits the proliferation of myeloma cells. It has also been reported that myeloma cells express Fas antigen, and in some of these cells apoptosis was induced by treatment with anti-Fas monoclonal antibody (mAb). In the present study, we demonstrated that ATRA increased Fas expression in the human myeloma cell line, U266B1. We observed that both apoptosis induction and growth inhibition were enhanced in cells exposed to a combination of anti-Fas mAb and ATRA compared with cells exposed to either treatment alone. We also examined whether ATRA modulated bcl-2, an anti-apoptosis protein, in U266B1 cells. Flow cytometry analysis revealed that the mean fluorescence intensity of bcl-2 protein was slightly decreased in cells treated with ATRA. These results indicate that in U266B1 cells, combined treatment with anti-Fas mAb and ATRA enhances the induction of apoptosis by modulating the expression of Fas and bcl-2 by ATRA.

Antibodies, Monoclonal↗