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Biomedical subjects

F Takaku

Publications and source records attributed to F Takaku.

At least 145 records · Page 8Linked to original sources
PubMed1991

Erythroid differentiation of K-562 cells induced by ethidium bromide.

The exposure of K-562 cells to ethidium bromide or acridine orange as DNA-intercalating agents induced their differentiation to hemoglobin-producing cells. The addition of L-ethionine or dimethylsulfoxide induced neither such differentiation nor changes in poly(A) polymerase activity of K-562 cells, though the addition of ethidium bromide, acridine orange, hydroxyurea, or 1-beta-arabinofuranosylcytosine induced erythroid differentiation and decreases in poly(A) polymerase activity. These results suggest that DNA-intercalation is one of the pathways triggering differentiation of K-562 cells and the decrease in poly(A) polymerase activity may be an important change associated with differentiation of K-562 cells.

Acridine Orange↗
PubMed1991

Enhancing effect of ubenimex (bestatin) on proliferation and differentiation of hematopoietic progenitor cells, and the suppressive effect on proliferation of leukemic cell lines via peptidase regulation.

Ubenimex (Bestatin) significantly enhanced the G- and GM-CSF-induced colony formation of human bone marrow cells at concentrations of 0.001, 0.01, 0.1 and 1.0 microgram/ml (21-61% enhancement), but not at 10 micrograms/ml. Ubenimex did not influence the EPO-induced erythroid colony and burst formation between 0.0001-100 micrograms/ml. Against human and mouse leukemic cell lines, the growth-inhibitory activities of ubenimex were dose-dependently observed. Aminopeptidase activities on U937 and TF-1 cells were almost inhibited with 10 and 100 micrograms/ml of ubenimex, respectively. Cross-linking studies of 125I-GM-CSF binding to TF-1 cells demonstrated that the 150-kDa band of 2 major bands was enhanced after incubation with 0.01 microgram/ml ubenimex but decreased after that with 100 micrograms/ml, and that the 95-kDa band was not changed at any concentration of ubenimex. Change in density of the 150-kDa band on ubenimex-treated TF-1 cells was correlated with that in expression of CD10 (neutral endopeptidase) on them, whereas that in expression of CD13 (aminopeptidase N) was not changed at any concentration. These results suggest that one possible mechanism of ubenimex action in hematopoietic progenitor cells is the up-regulation of the high affinity receptor for GM-CSF and that in leukemic cell lines is suppression of amino acid incorporation via peptidase regulation.

Aminopeptidases↗
PubMed1991

IL-1 up-regulates the expression of cytokine receptors on a factor-dependent human hemopoietic cell line, TF-1.

A factor-dependent human hemopoietic cell line, TF-1, requires interleukin 3 (IL-3) or granulocyte/macrophage colony-stimulating factor (GM-CSF) for its long-term growth. We have found that IL-4, IL-5, and IL-6 also support the growth of TF-1 and that IL-1 enhances the proliferative effect of these cytokines. Augmentation by IL-1 is associated with up-regulation of the receptors for IL-3, IL-5, GM-CSF, and erythropoietin (Epo). IL-1 increased the number of binding sites for IL-3 and Epo without changing their affinities. In contrast, IL-1 increased the number of high affinity binding sites for GM-CSF and IL-5, whereas the total number of binding sites was unchanged. Chemical crosslinking experiments indicated that the receptors for IL-3, IL-5, and GM-CSF were composed of two components and that the molecular masses of the larger components of these cytokine receptors were quite similar (120 kd). The enhanced expression of the larger components of the IL-3, IL-5, and GM-CSF receptors by IL-1 may be responsible for IL-1-induced up-regulation of these receptors. These observations are consistent with the model that the receptors for IL-3 and GM-CSF share a common component.

Cell Line↗
PubMed1991

Ki-ras activation in pancreatic carcinomas of Syrian hamsters induced by N-nitrosobis(2-hydroxypropyl)amine.

Five pancreatic carcinomas induced by N-nitrosobis(2-hydroxypropyl)amine in Syrian golden hamsters were analyzed for activation of Ki-ras at codons 12 and 13, using the polymerase chain reaction and direct sequencing. The Ki-ras gene was shown to be activated in four of the five carcinomas, and the results were further confirmed by subcloning and sequencing. All the mutations involved a G-to-A transition at the second position of codon 12, which resulted in a change at the amino acid level from glycine to aspartic acid. This mutation is identical with that reported for pancreatic tumors of Syrian hamsters induced by N-nitrosobis(2-oxopropyl)amine.

Animals↗
PubMed1991

A phase II trial of recombinant human granulocyte colony-stimulating factor in the myelodysplastic syndromes.

We conducted a phase II study of the intravenous administration of a glycosylated recombinant human granulocyte colony-stimulating factor (rhG-CSF) for 7-14 d in 41 patients with the myelodysplastic syndromes (MDS). Administration of rhG-CSF elicited striking rises in both leucocyte and neutrophil counts in the majority of the patients irrespective of the FAB subtypes of MDS. The rises in neutrophil counts were dose dependent and 5 micrograms/kg/d of rhG-CSF yielded approximately an 8-fold increase in neutrophil counts. Leucocytes and neutrophil counts started to increase shortly after the first injection of 5 micrograms/kg, was maintained at significantly elevated levels during 14 d of treatment, and returned to the pretreatment levels within several days following discontinuation of rhG-CSF. The action of rhG-CSF was specific for neutrophils since leucocytosis was due exclusively to neutrophilic increase associated with an increased marrow myeloid maturation. There were no consistent changes in the monocyte, eosinophil, lymphocyte, platelet or reticulocyte counts. After treatment, the percentage of marrow blast cells was reduced in eight of 13 evaluable patients with refractory anaemia with an excess of blasts (RAEB) or RAEB in transformation (RAEB-t). No patients developed acute leukaemia during the treatment or in the immediate follow-up period. The treatment was well tolerated with only minimal toxicity. The results suggest that rhG-CSF is a safe and effective way to promptly improve neutropenia in MDS patients.

Adolescent↗
PubMed1991

Unregulated expression of the erythropoietin receptor gene caused by insertion of spleen focus-forming virus long terminal repeat in a murine erythroleukemia cell line.

A murine erythroleukemia (MEL) cell line, F5-5, expressed 10,000 binding sites for erythropoietin (EPO) per cell, 10-fold more than was expressed by other murine erythroleukemia cell lines and normal erythroid progenitors. Northern (RNA) and Southern blot analyses revealed overexpression of mRNA for the EPO receptor (EPOR) and rearrangement of one of the EPOR gene alleles in F5-5 cells, respectively. Molecular cloning of F5-5-derived cDNA encoding EPOR revealed that the 5' noncoding region of the EPOR cDNA corresponds to the 3' long terminal repeat sequence of the polycythemic strain of Friend spleen focus-forming virus (F-SFFVP). The aberrant EPOR transcripts containing the 3' long terminal repeat sequence were mainly expressed in F5-5 cells. The same integration upstream of the EPOR gene was also observed in other subclones and the parent cell line. It is possible that overexpression of EPOR by viral promoter insertion will confer growth advantage to an F-SFFVP-infected erythroid progenitor cell, leading to positive clonal selection through further leukemogenic steps.

Amino Acid Sequence↗
PubMed1991

Organization and chromosomal localization of the human platelet-derived endothelial cell growth factor gene.

Human platelet-derived endothelial cell growth factor (hPD-ECGF) is a novel angiogenic factor which stimulates endothelial cell growth in vitro and promotes angiogenesis in vivo. We report here the cloning and sequencing of the gene for hPD-ECGF and its flanking regions. This gene is composed of 10 exons dispersed over a 4.3-kb region. Its promoter lacks a TATA box and a CCAAT box, structures characteristic of eukaryotic promoters. Instead, six copies of potential Sp1-binding sites (GGGCGG or CCGCCC) were clustered just upstream of the transcription start sites. Southern blot analysis using genomic DNAs from several vertebrates suggested that the gene for PD-ECGF is conserved phylogenetically among vertebrates. The gene for hPD-ECGF was localized to chromosome 22 by analysis of a panel of human-rodent somatic cell hybrid lines.

Animals↗
PubMed1991

Expression of perforin in infiltrating cells in murine hearts with acute myocarditis caused by coxsackievirus B3.

BACKGROUND: Cell-mediated autoimmunity has been strongly implicated in the pathogenesis of viral myocarditis. METHODS AND RESULTS: Using a murine model of acute myocarditis caused by coxsackievirus B3, we analyzed the phenotypes and morphology of the infiltrating cells in the hearts by immunofluorescence and electron microscopy. We also examined the expression of a cytolytic factor, perforin, in the infiltrating cells by immunoperoxidase and in situ hybridization. We found that the dominant population of the infiltrating cells were asialo GM1 positive, were negative for T-cell markers, and had electron-dense cytoplasmic granules, which is consistent with a morphology of large granular lymphocytes. Perforin was found in the cytoplasmic granules of the infiltrating cells expressing perforin messenger RNA. These findings provide for the first time the direct evidence that the first wave of cell infiltration in hearts mainly consists of killer cells and strongly suggests that perforin plays, in part, an important role in myocardial cell damage involved in acute viral myocarditis. T-helper cells and cytotoxic T lymphocytes made up the second wave of cell infiltration. CONCLUSIONS: As we previously reported, the expression of major histocompatibility complex class I antigen on cardiac myocytes induced by the infiltrating cells, such as killer cells, may facilitate the interaction between cardiac myocytes and cytotoxic T lymphocytes, and may lead to further myocardial cell damage in a later phase.

Acute Disease↗
PubMed1991

Heterogeneous mutations in the human lipoprotein lipase gene in patients with familial lipoprotein lipase deficiency.

The DNA sequences were determined for the lipoprotein lipase (LPL) gene from five unrelated Japanese patients with familial LPL deficiency. The results demonstrated that all five patients are homozygotes for distinct point mutations dispersed throughout the LPL gene. Patient 1 has a G-to-A transition at the first nucleotide of intron 2, which abolishes normal splicing. Patient 2 has a nonsense mutation in exon 3 (Tyr61----Stop) and patient 3 in exon 8 (Trp382----Stop). The latter mutation emphasizes the importance of the carboxy-terminal portion of the enzyme in the expression of LPL activity. Missense mutations were identified in patient 4 (Asp204----Glu) and patient 5 (Arg243----His) in the strictly conserved amino acids. Expression study of both mutant genes in COS-1 cells produced inactive enzymes, establishing the functional significance of the two mis-sense mutations. In these patients, postheparin plasma LPL mass was either virtually absent (patients 1 and 2) or significantly decreased (patients 3-5). To detect these mutations more easily, we developed a rapid diagnostic test for each mutation. We also determined the DNA haplotypes for patients and confirmed the occurrence of multiple mutations on the chromosomes with an identical haplotype. These results demonstrate that familial LPL deficiency is a heterogeneous genetic disease caused by a wide variety of gene mutations.

Adolescent↗
PubMed1991

Platelet-derived endothelial cell growth factor: structure and function.

Platelet-derived endothelial cell growth factor (PD-ECGF) is a 45-kDa single chain polypeptide, which stimulates the growth and chemotaxis of endothelial cells in vitro and angiogenesis in vivo. Purification from human platelets and cDNA cloning of PD-ECGF disclosed that it is a novel type of angiogenic factor without sequence similarity to hitherto known proteins. PD-ECGF is present in human platelets as well as in placenta. Amino acid sequencing of PD-ECGF from human placenta revealed that the placental form has an additional 5 amino acids at the N-terminus. In cultured cells, it is produced by normal fibroblasts as well as some transformed cell lines. PD-ECGF lacks a hydrophobic signal sequence and remains inside the producer cells. PD-ECGF may act at sites of injury as a wound hormone and thus play an important role under several physiological and pathological conditions.

Blood Platelets↗
PubMed1991

Mechanisms of cardiac hypertrophy and injury--possible role of protein kinase C activation.

To examine the molecular mechanisms by which mechanical stimuli induced cardiac hypertrophy and injury, we cultured rat neonatal cardiocytes in deformable dishes and imposed an in vitro mechanical load by stretching the adherent cells. Myocyte stretching increased total cell RNA content and mRNA levels of c-fos. Marked accumulation of c-fos mRNA followed increases in intracellular Na+ and protein kinase C activation. The accumulation of c-fos mRNA by cardiocyte stretching was suppressed by protein kinase C inhibitors but not by stretch channel blockers. Moreover, myocyte stretching increased inositol phosphate levels, and activation of protein kinase C by phorbolesters stumulated the expression of c-fos. We also examined TGF beta expression in the heart. TGF beta is known to be stimulated by protein kinase C activation, and the mRNA level of TGF beta was increased in in vivo heart by pressure overload. Furthermore, collagen synthesis was stimulated by TGF beta in cultured fibroblasts from hearts. These findings suggest that hemodynamic overload may stimulate cardiac hypertrophy and induce cardiac injury (fibrosis) through protein kinase C activation.

Animals↗
PubMed1991

Growth stimulating activity secreted by human anaplastic thyroid carcinoma cells.

In order to clarify the mechanism of rapid growth of anaplastic thyroid carcinoma, growth stimulating activity produced by the cancer cells in culture was studied. A cell line (HTh7) established from a biopsy specimen of anaplastic thyroid carcinoma was used throughout the study. Growth stimulating activity was determined as an activity to increase 3H-thymidine incorporation in rat thyroid cell line (FRTL5). Conditioned medium of HTh7 cells contained significant growth stimulating activity for FRTL5 cells. The activity was separated into two fractions with heparin agarose gel: heparin-binding and heparin-non-binding. In the medium, the heparin-non-binding activity was much greater than the heparin-binding one. The heparin-non-binding activity was acid stable. It was partially purified with gel filtration in an acidic condition followed by reverse phase HPLC. In gel filtration with a Sephacryl S-200 column, the activity was eluted later than the elution volume of cytochrome c (MW 12400) as several separated peaks. In reverse phase HPLC, however, the activity in these peaks was eluted as a single peak. The retention time of the active peak was almost the same as that of recombinant IGF-I. When measured by specific RIAs, the conditioned media concentrated 20 times contained both 0.35 ng/ml of IGF-I and 5.21 ng/ml of IGF-II. As for the heparin-binding mitogenic activity, when applied to heparin affinity HPLC column and eluted with a linear gradient of NaCl, the activity came out as one major peak with approximately 1.0 M NaCl.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma↗
PubMed1991

Peptide-based radioimmunoassay specific for GLUT1 glucose transporter.

A radioimmunoassay for the GLUT1 glucose transporter was developed with a synthesized peptide based on the sequence of the cDNA for GLUT1. A peptide corresponding to the COOH-terminal domain of the GLUT1 glucose transporter (Thr-Pro-Glu-Glu-Leu-Phe-His-Pro-Leu-Gly-Ala-Asp-Ser-Gln-Val) was synthesized and conjugated to keyhole limpet hemocyanin through the NH2-terminal of the peptide. An antibody was raised against this complex and affinity purified with the immobilized peptide. A second peptide, with tyrosine residue added to the NH2-terminal of the above peptide, was synthesized and used as a standard and iodinated for preparation of the radioactive ligand. The assay is highly reproducible, sensitive, and specific for the COOH-terminal domain of the GLUT1 glucose transporter. It has no cross-reactivity with the other glucose-transporter isoforms GLUT2 and GLUT4. Furthermore, the results obtained with this radioimmunoassay on the number of glucose transporters in human erythrocytes were in good agreement with previous studies based on cytochalasin B binding, suggesting that this radioimmunoassay is able to quantify the number of glucose transporters. The assay is completed within 4 h and can be used for simultaneous measurement of GLUT1 in many samples. In addition, it can be applied to the measurement of GLUT1 in several types of tissue.

Amino Acid Sequence↗
PubMed1991

Specificity of autoantibodies to histone H1 in SLE: relationship to DNA-binding domains.

Autoantibodies in the sera of patients with systemic lupus erythematosus were examined with respect to their specificity for proteolytic fragments of histone H1 that retain, or do not retain, DNA-binding domains. 16 of 31 sera contained IgG and IgM antibodies to histone H1. IgM antibodies to H1 in 8 sera (50%) were directed at 18 kD and 20 kD alpha-chymotrypic H1 fragments that bore binding sites for DNA, as identified by staining immunoblots containing the fragments with ssDNA plus 6/0, a mouse monoclonal antibody against ssDNA, IgM with this type of histone H1 specificity did not react with comparably-sized V8 protease fragments of H1. IgM antibodies to H1 in the other patients were directed against entirely different epitopes which were preserved in V8 protease digests of H1. In serial studies of three patients during different phase of their SLE, the level of antibodies against the 18 kD and 20 kD histone H1 fragments varied in parallel with the level of anti-ssDNA antibodies in one and varied inversely in the other two. The data suggest that a significant proportion of autoantibodies to histone H1 are directed at a limited number of epitopes localized to H1 fragments containing DNA-binding sites.

Animals↗
PubMed1991

[The effect of recombinant human granulocyte colony-stimulating factor (rG-CSF) on childhood neutropenias].

The clinical effect of recombinant human granulocyte colony-stimulating factor (rG-CSF), produced by Chinese hamster ovary cells, was studied in 27 patients with childhood neutropenias. The sample consisted of 8 patients with congenital neutropenia (Kostmann type), 9 with neutropenia with miscellaneous causes (5 chronic benign, 2 associated with hypogammaglobulinemia, 1 drug-induced, and 1 hypoplastic type), 3 with cyclic neutropenia, and 7 with severe aplastic anemia. The rG-CSF was given subcutaneously (or in a few cases intravenously) at a dose of 2 micrograms/kg/day for 7 days and 5 micrograms/kg/day for additional 7 to 28 days in cases with poor response. The rG-CSF was effective in 18 of 27 cases (67%). Patients with congenital neutropenia and aplastic anemia responded less frequently and poorly. The mean level of absolute neutrophil counts of 8 congenital neutropenia cases increased from 88/microliters to 2,718/microliters. That of 9 miscellaneous cases changed from 189/microliters to 7,224/microliters at a dose of 2 micrograms/kg/day. In 7 aplastic anemia cases pretreatment level of 220/microliters rose to 851/microliters, usually after increasing the dose up to 5 micrograms/kg/day. The rG-CSF was apparently effective in 3 cases of cyclic neutropenia. In any type of neutropenia, the effect was largely transient; after the discontinuation of rG-CSF, the absolute neutrophil counts tended to decrease to pretreatment levels within 1 to 2 weeks. The G-CSF was well tolerated, and only one case with mild lumbago and another with minimal elevation of transaminases were observed. We conclude that the rG-CSF can be effective for treating various types of childhood neutropenia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Clinical evaluation of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in autologous bone marrow transplantation].

We administered recombinant human granulocyte colony-stimulating factor (rhG-CSF) at 5 micrograms/kg/day by intravenous drip infusion for 21 consecutive days in autologous bone marrow transplanted patients. The period of posttransplant neutropenia was markedly shortened by the rhG-CSF treatment; mean days required for neutrophil recovery (greater than 500/mm3) of 14.3 days in the rhG-CSF group (n = 21) versus 27.8 days in the historical control group (n = 11). More importantly, the numbers of febrile days between day 15 and day 28 were found to be fewer in the rG-CSF group than in control group. These effects were obtained without delay in the recovery of other blood cell series and without any side effect. We conclude that the posttransplant use of the rhG-CSF is beneficial for prevention and treatment of infectious complications after autologous bone marrow transplantation.

Adolescent↗
PubMed1991

[Hematological effect of 14 days treatment of recombinant human granulocyte colony-stimulating factor for neutropenia in myelodysplastic syndromes].

Nineteen patients with myelodysplastic syndromes (MDS) were treated with a glycosylated recombinant granulocyte colony-stimulating factor (rG-CSF) for improvement of neutropenia. rG-CSF was administrated intravenously at a dose of 5 micrograms/kg/day for 14 consecutive days. Most of patients responded to rG-CSF and an approximately 10 fold increase of the peak neutrophil counts was observed. The neutrophil counts were maintained at high level during the treatment period and returned to pretreatment levels several days after stopping rG-CSF. Consistent with the recovery of neutrophil, infectious complications improved in many cases. Effects of rG-CSF were confined to neutrophils, sparing blast cells and other blood cells. Eruption was observed in one patient as toxicity. We conclude that rG-CSF therapy is effective in improving neutropenia with MDS patients.

Adult↗