Biomedical subjects

T Maekawa

Publications and source records attributed to T Maekawa.

At least 19 recordsLinked to original sources

PubMed1992

Transcriptional regulation by a point mutant of adenovirus-2 E1a product lacking DNA binding activity.

The adenovirus E1a protein (E1A) regulates transcription through interaction with transcription factors bound to DNA, like cAMP response element BP1/ATF2, or through dissociating E2F transcription factor complex. However, it was also reported that E1A can bind to DNA (Chatterjee, P. K., Bruner, M., Flint, S. J., and Harter, M. L. (1988) EMBO J. 7, 835-841), and it is not clear whether DNA binding of E1A is involved in a part of the process of transcriptional regulation by E1A. In this paper, the small region of E1A that is responsible for DNA binding was identified and a point mutant lacking DNA binding activity was constructed. Analysis of deletion mutants of E1A proteins expressed in bacteria showed that a basic region between amino acids 201 and 216 of E1A is essential for DNA binding. Point mutation of arginines at amino acid numbers 205 and 206 to aspartic acids completely abolished the DNA binding activity of E1A. Using this mutant, the requirement of the E1A DNA binding for E1A-dependent transcriptional regulation was examined. trans-Activation of the adenovirus E4 promoter and trans-repression of the human c-erbB-2 promoter by this point mutant were examined by cotransfection experiments. Mutations of the E1A DNA-binding domain affected neither the E1A-induced trans-activation nor trans-repression at all. These results give complete proof that the DNA binding activity of E1A is not required for transcriptional regulation by E1A.

Adenovirus E1A Proteins↗

PubMed1992

c-Jun represses the human insulin promoter activity that depends on multiple cAMP response elements.

Glucose is known to increase the cAMP concentration in pancreatic beta cells. To determine the mechanism by which cAMP augments insulin gene expression, we first identified the cAMP response elements (CREs) of the human insulin gene. In DNase I footprint analysis, the bacterially synthesized CRE-binding protein, CRE-BP1, protected four sites: two sites in the region upstream from the insulin core promoter, one site in the first exon, and one site in the first intron. To examine the roles of those four sites, we constructed a series of DNA plasmids in which the wild-type and mutant insulin promoters were linked to the chloramphenicol acetyl-transferase gene. Studies of the transcriptional activity of these plasmids after transfection into hamster insulinoma (HIT) cells showed that these four sites contributed additively to the cAMP inducibility of the insulin promoter. Surprisingly, the c-jun protooncogene product (c-Jun) repressed the cAMP-induced activity of the insulin promoter in a cotransfection assay with the c-Jun expression plasmid. Northern blot analysis demonstrated that the level of c-jun mRNA was dramatically increased by glucose deprivation in HIT cells. These results suggest that glucose may regulate expression of the human insulin gene through multiple CREs and c-Jun.

Animals↗

PubMed1992

Human interleukin-9 supports formation of a subpopulation of erythroid bursts that are responsive to interleukin-3.

We have investigated the biological activities of recombinant human interleukin-9 (IL-9) on enriched hematopoietic progenitors, alone or in combination with other cytokines, including Epo, G-CSF, IL-3, and GM-CSF, under serum-containing and serum-free cultures. IL-9 alone did not support colony formation. However, IL-9 plus Epo induced erythroid burst (BFU-E) formation derived from peripheral blood (PB) progenitors. Delayed addition experiments demonstrated that a part of bone marrow (BM) derived BFU-E, which seems to be immature, only responded to IL-9 and formed erythroid bursts. The burst-promoting activity (BPA) of IL-9 was confirmed using neutralizing aIL-3, aGM-CSF, and aIL-9 antisera and serum-free culture. IL-9 supported a part of BFU-E population that respond to IL-3, which was almost identical to the number of BFU-E supported by GM-CSF. IL-9 had no additive effect on erythroid and mixed colony formation supported by IL-3. In contrast, IL-9 showed an additive effect on erythroid burst formation supported by GM-CSF in serum-free culture. These data suggest that IL-9 and GM-CSF act on distinct IL-3-responsive BFU-E population. In addition, delayed addition experiment clearly demonstrated that IL-9 supports survival and the early stage of proliferation of BFU-E. These results led us to propose that IL-9 possibly acts as a BPA and selectively supports a subpopulation of early class of BFU-E that respond to IL-3.

Cell Division↗

PubMed1992

Phosphorylation of a 225-kDa centrosomal component in mitotic CHO cells and sea urchin eggs.

Components of centrosomes are those among cellular proteins that are phosphorylated at the transition from interphase to mitosis. Using an anti-phosphoprotein antibody (CHO3) directed against isolated mitotic CHO spindles, we identified a 225-kDa centrosomal phosphocomponent in mitotic CHO cells and in cleaving sea urchin eggs. The 225-kDa protein is tightly attached to the centrosome, which allowed us to separate it from other spindle-associated factors by high salt extraction. Phosphorylation of the 225-kDa protein occurred during mitosis. This was shown by isotope labeling on gels as well as by visualization of thiophosphorylated centrosomes with an anti-thiophosphoprotein antibody (M. Cyert, T. Scherson, and M. W. Kirschner, 1988, Dev. Biol. 129, 209) after preincubation with ATP-gamma-S in vivo and in vitro. Mitotic spindles isolated from CHO cells retained their ability to phosphorylate the centrosomal component, whereas sea urchin spindles did not, possibly due to loss or inactivation of protein kinase(s) during spindle isolation. The enzyme associated with isolated CHO spindles was extractable by high salt treatment and was capable of phosphorylating many spindle components, including the 225-kDa centrosomal protein of CHO cells and sea urchin embryos. Such high salt extracts contain protein kinases, including cell cycle control protein kinase p34cdc2, suggesting that the enzyme responsible for centrosomal phosphorylation could be p34cdc2 or other downstream mitotic kinases activated by the action of p34cdc2.

Animals↗

PubMed1992

A new myeloblastic leukemia cell line with double minute chromosomes. Induction of methotrexate resistance and dihydrofolate reductase gene amplification.

To test the relationship between DMs and drug resistance in newly established AML cell lines, KY821, and its clone KY821A3, the latter had lost DMs during cloning, were cultured in increasing concentrations of MTX. KY821 became resistant against 2 x 10(-4) M MTX, whereas KY821A3 did against 2 x 10(-5) M MTX in a same period. Enhanced enzyme activities of DHFR were correspondent to the increased DMs numbers and DHFR gene amplification in both resistant clones. The amplified DHFR gene was located on DMs by in situ hybridization. These data indicated that the presence of DMs in KY821 would facilitate the acquisition of drug resistance.

Chromosome Aberrations↗

PubMed1992

Clinical features of long-term survivors of refractory myelodysplastic anemias. A Japanese cooperative study.

Eighty-one of 473 patients with refractory myelodysplastic anemias registered by the Japanese Cooperative Study Group prior to January 1987 survived more than 5 years. At presentation, most patients had mild cytopenia, a less aggressive form of the disease (48 with refractory anemia, 23 with refractory anemia with ring sideroblasts, 10 with refractory anemia with excess of blasts), less blast cells in the marrow and blood, and onset at younger ages. Their clinical profiles 5 years after presentation showed no significant improvement. The results suggest that the long-term survivors were found in a subpopulation of patients with a favorable prognosis and that it is a part of the natural course rather than the results of treatment.

Adolescent↗

PubMed1992

Thrombolytic therapy of synthetic graft occlusions before vascular reconstructive procedures.

The objective of this study was to evaluate the impact of thrombolysis of synthetic grafts before urgent vascular reconstruction. In 29 patients, 41 thrombosed synthetic grafts that underwent intraarterial thrombolysis were studied. The cases were divided into three groups: group I--complete thrombolysis followed by reconstruction; group II--complete thrombolysis alone; and group III--incomplete lysis requiring reconstruction or sympathectomy. Follow-up ranged from 1 to 556 days (mean: 149 days). Kaplan-Meier analysis was used to determine patency and limb salvage rates. One-year patency and limb salvage rates were 53% and 95%, 34% and 67%, and 38% and 48%, respectively, for groups I, II, and III. Eighteen complications occurred in 16 of the 41 (39%) episodes. One patient died of intracranial hemorrhage. The best results were achieved when complete lysis was followed by appropriate reconstruction. Patency was equally poor in complete thrombolysis alone and reconstructions required by incomplete thrombolysis. Limb salvage was better after complete thrombolysis, regardless of the appropriate reconstruction.

Aged↗

PubMed1992

Bilineage response in refractory aplastic anemia patients following long-term administration of recombinant human granulocyte colony-stimulating factor.

5 patients with refractory aplastic anemia (AA) received long-term administration (2-11 + months) of recombinant human G-CSF (rhG-CSF) in doses from 250-500 micrograms/body/day by intravenous infusion or 75-300 micrograms/body/d by subcutaneous injection. All 5 evaluable patients showed a substantial increase in absolute neutrophil count (ANC) with a recovery of myeloid components in the bone marrow after 1 to 2 months of treatment. Interestingly, 2 out of the 5 patients showed a dramatic improvement in severe anemia after 2 to 4 months of treatment accompanying a recovery of erythroid components in the bone marrow. In addition, there was no serious infection before or during therapy. Long-term administration of rhG-CSF was well tolerated because of its minimal toxicity. Clonal assay revealed a recovery of myeloid progenitors in all patients and a recovery of erythroid progenitors in 3 out of the 5 patients. These results suggest that long-term administration of rhG-CSF at least mobilizes residual myeloid as well as erythroid progenitor cells and induces a bilineage response in severe refractory AA.

Adult↗

PubMed1992

Effect of ciclosporin on cardiac output and regional blood flow in rats: ciclosporin-induced nephropathy and its prevention with calcium channel blocker.

The effect of ciclosporin (CS) on cardiac output (CO) and regional blood flow was studied using the microsphere method in heminephrectomized rats with and without renal arterial clamping prior to the administration of CS. The effect of a calcium (Ca) channel blocker, verapamil, was also examined on CS-induced nephropathy. CS at a dose of 40 mg/kg per day was given orally using a gastric tube for 7 days. Verapamil was given in the drinking water for 7 days. Significant increases in blood urea nitrogen (BUN) and serum creatinine (sCr) with a significant decrease in renal inulin clearance (CIn) were noted after 7 days of CS administration in both intact and ischemic-kidney groups, indicating the development of CS-induced nephropathy. The ischemic-kidney group showed a significantly severe nephropathy as compared with the intact-kidney group. As for change in CO and regional blood flow, CS caused a significant decrease in CO, renal blood flow (RBF) and brain blood flow, while hepatic arterial blood flow and muscular blood flow significantly increased. The renal outer cortical blood flow decreased markedly while the inner cortical blood flow remained unchanged. Although verapamil slightly but significantly decreased mean arterial blood pressure in CS-treated rats, CO and its distribution did not change. BUN and sCr were not significantly ameliorated in the intact-kidney group. However, in the ischemic-kidney group, verapamil caused a significant improvement in RBF, ameliorating CS-induced elevation of BUN and sCr, and a decrease in CIn.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Hyperbaric oxygen therapy for control of intractable cyclophosphamide-induced hemorrhagic cystitis.

We report a case of intractable hemorrhagic cystitis due to cyclophosphamide therapy for Wegener's granulomatosis. Conservative treatment, including bladder irrigation with physiological saline and instillation of prostaglandin F2 alpha, failed to totally control hemorrhage. We then used hyperbaric oxygen at an absolute pressure of 2 atm, 5 days a week for 8 consecutive weeks. The bleeding ceased completely by the end of treatment and the patient remained free of hematuria thereafter. No side effect was noted during the course of therapy. In future, this form of therapy can offer a safe alternative in the treatment of cyclophosphamide-induced hemorrhagic cystitis.

Cyclophosphamide↗

PubMed1992

[Subcapsular orchiectomy using the ultrasonic surgical aspirator in patients with advanced prostatic cancer].

We report a technique for performing subcapsular orchiectomy using the ultrasonic surgical aspirator (USA). The procedure was simple and safe, and was completed within one hour in 2 patients on whom it was carried out. Operative complications such as bleeding, postoperative pain and wound swelling were minimal, and compression dressings were not necessary. Postoperatively, the serum testosterone value was lowered to the castrate level. We conclude that subcapsular orchiectomy using USA is superior to conventional bilateral scrotal orchiectomy, and will be a useful option.

Humans↗

PubMed1992

[Effects of isosorbide dinitrate on regional cerebral blood flow and intracranial pressure in cats].

The effects of isosorbide dinitrate (ISDN) on regional cerebral blood flow (rCBF) and intracranial pressure (ICP) were examined in cats. A low dose of ISDN (2.5 micrograms/kg/min) infusion did not show any changes in cerebral hemodynamics. During high dose of ISDN (5.0 micrograms/kg/min) or NTP (5.0 micrograms/kg/min) infusion, mean blood pressure (mBP) decreased by 10 to 20% accompanied by decreased cerebral perfusion pressure (CPP: mBP-ICP), however, rCBF or ICP did not change. It is concluded that intravenous administrations of ISDN in a dose of 2.5-5.0 micrograms/kg/min that produce slight decrease in blood pressure did not influence on cerebral hemodynamics.

Animals↗

PubMed1992

[Nicergoline, an ergot alkaloid, improves ischemic brain damage by ameliorating the decreased cerebral blood flow and metabolism in spontaneously hypertensive rats].

Effects of ergot alkaloids, nicergoline (NIC), on survival rate, brain water content, local cerebral blood flow (LCBF: 14C-iodoantipyrine) and glucose utilization (LCGU: 14C-2-deoxyglucose) were examined after bilateral carotid artery occlusion (BCAO) in spontaneously hypertensive rats. Two series of study were performed; the permanent BCAO and 3-hr-BCAO study. After permanent BCAO, the survival rate at 24 hrs of 32% (8 mg/kg, i.p.) or 38% (16mg/kg) in NIC group was higher than that in non-treated group (12%). At the end of 3-hr-BCAO, the increase in water content (dry-wet) in di-mesencephalon was less in NIC (100 micrograms/kg/min, i.v.) group than that in non-treated group. The decrease in LCBF in caudate-putamen (CP), parietal cortex (PC), thalamus (TH), hypothalamus (HT), and substantia nigra (SN) were less in NIC group than those in non-treated group. At the 2-hr-reperfusion after 3-hr-BCAO, the decrease in LCBF in TH and HT were less in NIC group than those in non-treated group. The LCGU in sensory motor cortex, CP, PC, HT, inferior colliculus and pons-reticular were higher in NIC group than those in non-treated group. From these results, it is concluded that nicergoline may have ameliorative effects on survival rate related to the prevention of decreased cerebral blood flow and metabolism following brain ischemia.

Animals↗

PubMed1992

Synergistic suppression of the clonogenicity of U937 leukemic cells by combinations of recombinant human interleukin 4 and granulocyte colony-stimulating factor.

The actions and interactions of purified recombinant human (rh) interleukin 4 (IL-4) and granulocyte colony-stimulating factor (G-CSF) on the clonogenicity of human leukemic cell line U937 were studied in vitro. Parameters analyzed were the suppression of stem cell generation using sequential clonal cultures, alterations of surface antigen expression, and morphological changes. IL-4 alone (10 U/ml) and G-CSF alone (1000 U/ml) only slightly reduced colony numbers (80% +/- 7% and 87% +/- 7% of control colonies, respectively). However, IL-4 interacted synergistically with G-CSF to further reduce the colony number (46% +/- 8% of control colonies) and suppress the self-renewal ability (clonogenicity) of U937 cells. This synergistic effect was not eliminated by cultures containing neutralizing concentrations of anti-granulocyte-macrophage colony-stimulating factor (anti-GM-CSF), anti-interleukin 6 (anti-IL-6), anti-interferon-alpha (anti-IFN-alpha), anti-IFN-gamma, anti-transforming growth factor-beta (anti-TGF-beta) serum, and anti-tumor necrosis factor-alpha (anti-TNF-alpha) serum. The coexistence of IL-4 and G-CSF was required for at least 48 h to reveal the synergistic action as assessed by preincubation and delayed addition experiments. Combinations of IL-4 and G-CSF showed a significant increase in CD11b expression on U937 cells. This action was not observed with HL60, K562, ML-1, or KG-1 leukemic cell lines, and IL-4 did not show any synergistic suppression of clonogenicity of U937 leukemic cells in combination with other cytokines tested in this study. These results suggest that IL-4 in combination with G-CSF may have some capacity to synergistically suppress human leukemic cells of specific types with loss of clonogenicity.

Antibodies↗

PubMed1992

[Giant epidermoid cyst of the scrotum: a case report].

A 74-year-old male with the chief complaint of painless enlargement of a mass in the scrotum was diagnosed as having a giant epidermoid cyst on July 8, 1991. He had no past history of injury or pain of the scrotum. Magnetic resonance imaging (MRI) of the scrotum demonstrated a well-circumscribed homogeneous mass, and was distinguished from both normal testes. Under the diagnosis of intrascrotal epidermoid cyst, the mass was resected surgically. The mass measured 23 x 15 x 15 cm, and it contained liquids. The pathological diagnosis was epidermoid cyst of the scrotum.

Aged↗

PubMed1992

[Thrombelastography as a bedside monitor of coagulation and fibrinolysis during surgery--a report of three cases].

Three patients with abnormal hemostasis during surgery were reported. They were monitored by thrombelastography (TEG). The first case was a 48 year old male who underwent extravivo hepatectomy. TEG showed hypo-coagulability during anhepatic phase. After reperfusion to the liver, the coagulability determined by TEG returned to a normal pattern. The second patient was a 32 year old female who underwent laparotomy to stop bleeding for cervico-vaginal laceration after delivery. The patient had been in severe hemorrhagic shock, and massive blood transfusion and fluid administration were performed. TEG showed remarkable hypocoagulability probably due to blood dilution and consumption coagulopathy. When TEG returned to a normal pattern after administration of fresh frozen plasma and fresh whole blood, the abnormal bleeding stopped. The third patient was a 48 year old male who underwent resection of metastatic brain tumor. He had hepatocellular carcinoma and liver cirrhosis. During surgery, abnormal bleeding was seen at surgical field, when TEG revealed remarkable hyper-fibrinolysis. After antifibrinolytic therapy coupled with replacement therapy, TEG returned to a normal pattern and the abnormal bleeding ceased. We conclude that TEG is a useful bed side monitor for the diagnosis of coagulopathy and hyper-fibrinolysis during surgery.

Adult↗

PubMed1992

A multicenter prospective study on the treatment of chronic idiopathic thrombocytopenic purpura.

A multicenter prospective study on the treatment of chronic idiopathic thrombocytopenic purpura (ITP) was conducted by the Idiopathic Disorders of Hematopoietic Organs Research Committee (IDHORC), the Ministry of Health and Welfare of Japan. The aim of the study was to establish an improved therapeutic guide for chronic ITP. Of the 247 eligible patients 175 have been followed up to the present time, 16 patients have died, and 56 have been lost to follow-up. The median follow-up time was 55 months (range: 1 to 91 months). Of the 206 patients treated with corticosteroids, 13.1% achieved sustained complete remission. Splenectomy produced remissions in 52.5% of 72 patients evaluated 12 months after operation. Eighty-five patients were treated with immunosuppressive agents, but the response rates were low and the effect was transient in most cases. In the patients followed up without any specific treatment, the mean platelet counts showed slight improvement. Of the 16 patients who died during the observation period, only one died of bleeding; the remaining 15 died of causes unrelated to thrombocytopenia. It is noteworthy that five patients who were treated with corticosteroids or immunosuppressive agents died of infection.

Adolescent↗

PubMed1992

[Aplastic anemia].

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Anemia, Aplastic↗