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T Shimokawa

Publications and source records attributed to T Shimokawa.

At least 91 records · Page 5Linked to original sources
PubMed1995

The molecular mechanism of the induction of the low density lipoprotein receptor by chenodeoxycholic acid in cultured human cells.

In a cultured human hepatoblastoma cell line, Hep G2, chenodeoxycholic acid (CDCA) induced LDL receptor mRNA levels approximately 4 fold and mRNA levels for HMG-CoA reductase and HMG-CoA synthase two fold. In contrast, the mRNA levels for mevalonate kinase, farnesyl pyrophosphate synthase and squalene synthase were not changed significantly. The pattern of the induction of the sterol-sensitive genes was similar to the induction by N-acetyl-leucyl-leucyl-norleucinal (ALLN), an SREBP degradation inhibitor, suggesting that CDCA may increase mature SREBPs. CDCA could inhibit the 25-hydroxycholesterol mediated inactivation of SREBP without affecting mRNA levels of SREBPs. These results suggest that CDCA can affect sterol metabolism by a novel mechanism involving the inhibition of the oxysterol-mediated inactivation of SREBP.

Alkyl and Aryl Transferases↗
PubMed1995

Cosmid assembly and anchoring to human chromosome 21.

A human chromosome 21-specific cosmid library from the Lawrence Livermore National Laboratory has been analyzed by two complementary methods, fingerprinting and hybridization; 40% coverage of the entire chromosome 21 has been achieved. To prepare a contig pool, approximately 9300 cosmid clones randomly selected from the library were fingerprinted and automatically assembled into 467 overlapping sets by the fluorescence-tagged restriction fragment method. The average size of the overlapping sets was 9.5 cosmids with minimal tiling paths consisting of 5.4 cosmids with a 10-kb extension each. However, as many as 10% of overlaps within members were estimated to be false. For regional localization, we hybridized gridded arrays of cosmids with inter-Alu-PCR probes obtained from YAC clones and somatic cell hybrids and assigned 592 cosmids to 26 subregions of 21q. Of these, 371 clones were incorporated into 139 contigs, anchoring the total 1864 cosmids to the subregion. The remaining 221 clones were mapped as orphans. To correlate the cytogenetic, YAC, and cosmid maps on 21q, the translocation breakpoints of the chromosomes contained in the somatic cell hybrids were mapped with respect to the STS content of the YACs. From the gene cluster regions, 176 ribosomal and 25 alphoid clones were isolated by hybridization. Together, these sets of anchored contigs and cosmids will provide a valuable resource for construction of a high-resolution map and for isolation of genes of interest from chromosome 21.

Animals↗
PubMed1995

Quantitative and qualitative comparative analysis of gradient-separated hematopoietic cells from cord blood and chemotherapy-mobilized peripheral blood.

Some of the uncertainty regarding the use of cord blood (CB) in transplant settings includes the suspected relative rarity of hematopoietic stem cells (SC) in CB and the feasibility of incorporating a cell separation protocol to remove red blood cells, which may result in an unacceptable loss of SC. To address this uncertainty, we isolated a SC fraction by Percoll or Ficoll gradients from CB and peripheral blood (PB), which had been mobilized by chemotherapy. The frequencies of mononuclear cells (MNC), CD34+ cells, colony-forming units granulocyte-macrophage (CFU-GM), and the output of colony-forming cells (CFC) after five weeks in long-term culture (LTC) assay were then evaluated. The mean numbers of these cells per ml of CB sample before gradient separation were, respectively, 4.9 x 10(6), 13.8 x 10(4), 3.0 x 10(3) and 681 (n = 37). In the recovery phase of PB, these numbers were, respectively, 2.0 x 10(6), 14.9 x 10(4), 3.5 x 10(3) and 270 per ml of processed blood at apheresis (n = 35). After Percoll separation, the recovery rates of these cells were, respectively, 29%, 92%, 97% and 95% in CB, and 65%, 87%, 123% and 102% in PB. After Ficoll separation of CB, the rates were, respectively, 55%, 107%, 92% and 105%. These results suggest that CB contains an adequate number of more immature progenitors which can be retained after cell separation with Percoll or Ficoll, thereby making it feasible to incorporate a cell processing procedure into a CB transplant protocol. Percoll separation provided a greater enrichment of cells than Ficoll.

Adolescent↗
PubMed1995

[Quantitative autoradiographic analysis of the binding of mosapramine to dopamine D3-receptors].

The affinity of mosapramine, an iminodibenzyl antipsychotic, to dopamine D3-receptors in rat brain was investigated by quantitative autoradiography of [3H]-7-OH-DPAT, a selective D3-ligand. Autoradiograms showed restricted distribution of [3H]7-OH-DPAT binding sites, with very high levels on the islands of Calleja (ICj), olfactory tubercle (Tu) and nucleus accumbens, while low but distinct labeling was observed in the molecular layer of lobule 10 of the cerebellum and caudate putamen (CPu). Binding of [3H]7-OH-DPAT completely disappeared when 1 microM dopamine was added, and it was reduced by the addition of mosapramine in a concentration-dependent manner. The displacing effect of mosapramine was more potent than that of haloperidol or clozapine in the brain regions examined. Mosapramine showed more potent affinity to receptors in Tu and ICj than those in CPu. On the other hand, haloperidol and clozapine did not show such regional differences. These results suggest that the high affinity of mosapramine to D3-receptors participates in, at least in part, the development of the clinical effects of mosapramine.

Animals↗
PubMed1995

[Study on peripheral blood stem cells mobilized by different chemotherapies with granulocyte-colony stimulating factor in ovarian cancer].

A new therapeutic strategy for advanced ovarian cancer is to administer ultra-high doses of anticancerous drugs, followed by peripheral blood stem cell transplantation (PBSCT) to recover normal marrow functions. There are, however, no clear regimens to induce mobilization of peripheral blood stem cells (PBSCs). We therefore used three different chemotherapies and granulocyte colony-stimulating factor (G-CSF) to produce a rebound increase in PBSCs during myelosuppression by apheresis. Eleven patients with advanced ovarian cancer (FIGO Stage; IIc-1, IIIc-5, IV-4, Recurrence-1) received chemotherapy with CEP (cyclophosphamide: 500-750mg/m2, epirubicin: 50-70mg/m2, cisplatin: 70mg/m2), CEE (cyclophosphamide: 2,000mg/m2, epirubicin: 50mg/m2, etoposide: 300mg/m2, and PEC salvage (cisplatin: 75mg/m2, etoposide: 300mg/m2, cyclophosphamide: 1,000mg/m2) followed by lenograstim (G-CSF; 2 micrograms/kg subcutaneous injection daily for 14-18 days) to mobilize PBSCs. A range of 0-38.2 x 10(4) (mean +/- S.D.; 11.1 +/- 5.0 x 10(4) colony forming unit granulocyte-macrophage (CFU-GM)/kg in the CEP regimen (n = 15), 1.6-40.8 x 10(4) (mean +/- S.D.; 12.3 +/- 3.6 x 10(4) CFU-GM/kg in the CEE regimen (n = 11), and 8.6-11.4 x 10(4) (mean +/- S.D.; 10.0 +/- 2.0 x 10(4) CFU-GM/kg in the PEC salvage regimen (n = 2) were recruited by a single apheresis. Although the CEE regimen to mobilize PBSCs was much more efficient than the CEP regimen, a large number of PBSCs showing 38.2 x 10(4) CFU-GM/kg were mobilized by the CEP regimen with a dose-escalation of cyclophosphamide 750mg/m2 and epirubicin 70mg/m2. The number of CFU-GM/kg correlated well with that of CD34+ (r = 0.693).(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

[Horner syndrome due to mediastinal neurinoma--a case report].

Horner syndrome due to mediastinal neurinoma has been reported rare cases so far. We experienced a 55-year-old woman who developed Hornor syndrome due to mediastinal neurinoma and the patient received operation with no major complication. She was admitted to our hospital because of the left shoulder pain and the dilatation of the mediastinum on chest X-ray. She was found to have the left mild ptosis and CT scan showed left upper mediastinal tumor (12 cm in diameter) with tracheal compression. Aortography showed a 8.6 cm tumor stein and lower deviation of aortic arch. The feeding artery was branch of thyrocervical artery. Mediastinal neurinema was found by biopsy. During the operation, we found the origin was the left sympathetic nerve. The post operative course was uneventful however horner syndrome was progressed due to radical resection of the tumor.

Disease Progression↗
PubMed1995

Determination of mRNA levels of cholesterol biosynthesis enzymes and LDL receptor using ribonuclease protection assay.

We designed a rapid method for determining mRNA content of cholesterol biosynthesis enzymes and LDL receptor (LDLR) using a ribonuclease protection assay (RPA). 32P-labeled cRNA fragments for genes of human LDLR and the enzymes HMG-CoA synthase (HMGS), HMG-CoA reductase (HMGR), mevalonate kinase (MK), farnesyl pyrophosphate synthase (FPPS), and squalene synthase (SQS) were prepared by in vitro transcription. Total RNA prepared from HepG2 cells was hybridized with the cRNA probe and the hybridized mRNA was determined under protection from RNase digestion. Probe content used in this assay was excess in determining the desired mRNA in total RNA, and surplus probes were completely digested using RNase under standard conditions. When cells were cultured in DMEM supplemented with 10% fetal calf serum (FCS), mRNA levels of FPPS, SQS, and LDLR were about 4- to 7-fold higher than those of HMGS, HMGR, and MK. On incubation with DMEM supplemented with 10% lipoprotein-deficient serum (LPDS) for 8 h, all messenger RNA levels increased 1.5- to 3.5-fold. In addition, when the HMG-CoA reductase inhibitor compactin was added to 10% LPDS-DMEM, these levels increased even further and the change in mRNA level seemed to differ between the enzymes and LDLR. From these results, we conclude that RPA is a useful method for determining the very small amount of mRNA level of cholesterol biosynthesis enzymes and LDLR in the cell.

Base Sequence↗
PubMed1995

[Marked bone marrow necrosis preceding acute monoblastic leukemia].

Bone marrow necrosis is rarely diagnosed during life but is more often seen at autopsy by accident. The prognosis of patients with bone marrow necrosis secondary to neoplastic disease is extremely poor. We described a 53-year-old man with bone marrow necrosis preceding acute monoblastic leukemia. He was admitted in June, 1994, for continuous back pain and marked elevation of serum lactate dehydrogenase. After admission, a hematologic examination showed progressive pancytopenia in peripheral blood and bone marrow necrosis. He was diagnosed as AML (M5) from the sudden appearance of leukemic blasts in the peripheral blood two months later. Induction therapy was immediately administered according to JALSG-92 protocol. The patient suffered from tumor lysis syndrome after chemotherapy, but complete remission was achieved by dialysis.

Bone Marrow↗
PubMed1994

Isolation of human chromosome 21-specific cosmids and their uses in mapping of cosmid contigs on chromosomal subregions.

A cosmid library of 3 x 10(5) clones has been constructed from a human x hamster hybrid cell line, 153E9a3, which contains human chromosome 21 (HC21) as the only human chromosome. From 56,500 clones of this library, 229 HC21-specific cosmids have been isolated by their hybridization to total human DNA and by their failure to hybridize to total Chinese hamster DNA. The cosmids isolated were then characterized, of these, 28 cosmids (12.2% of those tested) contained Not1 site(s), and 41 cosmids were localized on the eight subregions of HC21 by differential hybridization with Alu-PCR products obtained from a hybrid mapping panel. The cosmids localized were further integrated into the existing contigs using the end-specific probes of the clone insert. Therefore, they provided useful anchor points for contig mapping and walking.

Animals↗
PubMed1994

[A clinical study of sixteen polycythemia vera cases--acute myeloblastic leukemia in patients with polycythemia vera].

The clinical course of 16 patients with polycythemia vera (PV), treated in the period 1982 to 1993, was shown. Splenomegaly occurred in three fourths of these patients (75%), and hypertension was a major symptom. Thrombosis such as myocardial infarction and cerebral infarction was noted. Eight patients was treated with myelosuppressive agents and the 8 other patients were treated with phlebotomy. A 70-year-old male who was treated with mitobronitol (DBM) developed acute myeloblastic leukemia (AML) 11 years later. He was treated with multi-combination chemotherapy (BHAC-DMP), and entered complete remission, followed by early relapse. He became refractory to chemotherapy and died of acute pneumonia 6 months later. Median survival of 16 cases of PV was more than 10 years, and long-term treatment and care are necessary.

Adult↗
PubMed1994

[A case of essential thrombocythemia with clonal evolution in the terminal phase].

This 50-year-old male was admitted to the hospital on April 1983 with complaints of severe chest pain attacks 2 weeks previously. Laboratory data: On admission the blood findings were Hb 14.3 Gm/dl of blood, RBC 4.70 million/mm3, WBC 11,600/mm3 and a platelet count of 1.1 million/mm3. ECG showed elevation of ST-T in V1 to V4. Serum LDH and CPK levels were high. He was diagnosed as acute myocardial infarction with thrombocythemia. Three days after admission he abruptly fell into a semicomatose state and left hemiplesia. Head computed tomography showed a large, low-density lesion in the right mid-cerebral artery area, and we also diagnosed cerebral infarction. He was given nimustine (ACNU) 100 mg/week three times as remission induction therapy. For maintenance chemotherapy, at first we administered mitobronitol (DBM) 150 mg/day then changed to intermittent administration of ACNU 100 mg. On September 1991, the patient was admitted to the hospital with progressive anemia and uncontrollable thrombocythemia. Bone marrow chromosome analysis revealed aneuploidy. The patient received interferon alpha 3 million unit/day. The thrombocythemia could be controlled but his general condition deteriorated. On April 1992, he died of interstitial pneumonia.

Aneuploidy↗
PubMed1993

Isolation of multiple activities from mouse FM3A cells which promote homologous pairing of DNA molecules.

We describe the detection and partial purification of three homologous pairing activities from extracts of mouse mammary carcinoma FM3A cells. These activities, designated MHP1a, 1b, and 1c, form joint molecules between circular single-stranded DNA and homologous linear duplex DNA and are distinguished from one another by their chromatographic behaviors or isoelectric properties. The reactions promoted by these activities require homologous substrates but not ATP. All the reactions also show Mg2+ dependence in the absence of exogenous ATP. Analysis of the reaction products has revealed that strand exchange proceeds for lengths of up to at least 271 bp during the homologous pairing reaction. The finding of multiple types of homologous pairing and strand exchange activity in mouse cells may facilitate the elucidation of the mechanism of homologous recombination in somatic mammalian cells.

Ammonium Sulfate↗
PubMed1993

Pharmacokinetics of cisplatin instilled into the pleural cavity following panpleuropneumonectomy in patients with malignant pleurisy due to lung cancer.

The pharmacokinetics of cisplatin instilled into the pleural cavity in patients with malignant pleurisy due to lung cancer were studied. Higher concentrations of total and free platinum in pleural effusion have been maintained for longer than 72 hours in patients who were subjected to panpleuropneumonectomy than in those who received simple drainage. Early rapid drop of total platinum within 6 hours was significant in the drainage group. Total platinum level in the serum of the panpleuropneumonectomy group gradually increased during 1-72 hours, however, that of the drainage group was highest at 1 hour after instillation and declined gradually with time. Free platinum in the serum was also present at lower concentrations in the panpleuropneumonectomy group than in the drainage group. These facts may be ascribed to the absorptive activity of parietal pleura which is present in the drainage group but absent in the panpleuropneumonectomy group. In summary, removal of the parietal pleura by panpleuropneumonectomy could cause cisplatin to be not only more active but also less toxic in patients with malignant pleurisy due to lung cancer.

Adenocarcinoma↗
PubMed1993

[A case of ALL complicated with acute pancreatitis and pancreatic pseudocyst caused by L-asparaginase ].

We reported a case of ALL complicated with acute pancreatitis caused by L-asparaginase (L-Asp). The patient was a 42-year-old man, who showed eosinophilia in peripheral blood and an increase of lymphoblast in bone marrow. He was diagnosed as ALL (L2) and treated by JALSG '87 protocol. Remission induction chemotherapy including L-Asp was administered by 5,000 IU i.v. for 10 days. The day after giving all dose of L-Asp, slight epigastralgia developed and then became severe. After two days, s-amylase was markedly elevated, and the patient was diagnosed as acute pancreatitis caused by L-Asp. He was treated conservatively, but hyperglycemia occurred. The epigastrial tumor was palpable and gradually grew in size. CT-scan and abdominal ultrasonography revealed pancreatic pseudocyst, so he was treated by percutaneous cyst drainage. The patient died of a relapse of ALL. The prophylaxis and early diagnosis of the pancreatitis and hyperglycemia caused by L-Asp are very difficult. We have to examine more cases and pay greater attention to the chemotherapy, including L-Asp.

Acute Disease↗
PubMed1992

Identification of two types of homologous DNA pairing activity in mouse cells.

We have identified two types of homologous DNA pairing activity in mouse cell extracts by a strand-transfer assay. Both activities are separated from each other by anion-exchange chromatography; neither of them needs ATP. One requires magnesium ion and is stimulated by Escherichia coli single-stranded DNA binding protein, whereas the other does not require the ion and shows a higher affinity for a left-handed Z-DNA.

Adenosine Triphosphate↗
PubMed1992

Prostaglandin endoperoxide synthase. The aspirin acetylation region.

Aspirin selectively acetylates Ser-530 of prostaglandin endoperoxide (PGH) synthase-1. This causes inactivation of the cyclooxygenase activity of the enzyme, but does not appreciably affect its peroxidase activity. Although the aspirin-acetylated enzyme is inactive, we found that PGH synthase-1 in which Ser-530 had been replaced with an alanine was catalytically active; accordingly, we proposed that aspirin inhibits cyclooxygenase activity by placing a larger than normal side chain at position 530 thereby interfering with arachidonate binding (DeWitt, D.L., El-Harith, E. A., Kraemer, S. A., Andrews, M. J., Yao, E. F., Armstrong, R. L., and Smith, W. L. (1990) J. Biol. Chem. 265, 5192-5198). As a further test of this hypothesis we have used site-directed mutagenesis and transient expression in cos-1 cells to prepare and characterize five additional substitutions of Ser-530. Consistent with our proposal, the presence of amino acids with bulky side chains at position 530 inhibited cyclooxygenase activity and decreased the apparent affinity of the enzyme for arachidonate. In related work, we characterized a series of mutant PGH synthases-1 having substitutions at residues adjoining Ser-530, including Phe-529, Leu-531, Lys-532, and Gly-533, in order to evaluate the contributions of each residue to cyclooxygenase catalysis. The most significant conclusion of this part of the study is that residues 529-533 all are important for the peroxidase activity as well as the cyclooxygenase activity of PGH synthase-1. Phe-529, in particular, was found to be critical for PGH synthase-1 structure and catalysis; some substitutions at this position led to the production of proteins lacking about 100 amino acids from their COOH termini.

Acetylation↗
PubMed1992

Expression of prostaglandin endoperoxide synthase-1 in a baculovirus system.

A cDNA coding for ovine prostaglandin endoperoxide (PGH) synthase-1 was used to construct a recombinant baculovirus which was expressed in Spodoptera frugiperda (Sf9) insect cells. Two proteins reactive with anti-PGH synthase antibody were produced. A larger protein (Mr = 72,000) coelectrophoresed with native enzyme; a smaller, more abundant protein (Mr = 66,000) was unglycosylated enzyme. About 90% of both the immunoreactivity and the cyclooxygenase activity were present in a low speed (10(5) g x min) pellet; variable but low peroxidase activities were observed in this fraction. The specific cyclooxygenase activity of solubilized PGH synthase-1 from Sf9 cells was 56 units/mg versus 112 units/mg for the same cDNA expressed in cos-1 cells. The baculovirus-insect cell system is not ideal for generating large amounts of active PGH synthase-1 apparently because of inefficient N-glycosylation.

Animals↗