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Biomedical subjects

F Takaku

Publications and source records attributed to F Takaku.

At least 181 records · Page 10Linked to original sources
PubMed1990

[Clinical effect of recombinant human G-CSF on neutropenia induced by chemotherapy for non-Hodgkin's lymphoma].

A clinical trial of recombinant human granulocyte colony-stimulating factor (rG-CSF), produced by Chinese hamster ovary cells, was conducted in 66 patients receiving intensive chemotherapy for non-Hodgkin's lymphoma. Each patient received 2 cycles of CHOP therapy, and one cycle of them was performed with rG-CSF treatment and another one without rG-CSF treatment, in a cross-over fashion. rG-CSF (0.4, 2, 5, 10 micrograms/kg/day) was given intravenously or subcutaneously to each patient for 14 days from 2 days after initiation of the chemotherapy. rG-CSF increased the absolute neutrophil counts (ANC) at nadir, and reduced the period of neutropenia with ANC less than 1,000/mm3 and also the period for restoration to ANC greater than or equal to 2,000/mm3 after initiation of chemotherapy. These effects were remarkable at doses of more than 5 micrograms/kg/day intravenously and 2 micrograms/kg/day subcutaneously. Fourteen infective episodes were observed during the cycles of chemotherapy without rG-CSF treatment, while 7 infective episodes were observed during the cycles with rG-CSF treatment. rG-CSF was well tolerated. These results demonstrated that rG-CSF was effective in neutropenia induced by cancer chemotherapy at a intravenous dose of 5 micrograms/kg/day and a subcutaneous does of 2 micrograms/kg/day.

Adult↗
PubMed1990

Implantation of genetically manipulated fibroblasts into mice as antitumor alpha-interferon therapy.

Long-term parenteral administration of human alpha-interferon (HuIFN-alpha) is effective in the treatment of several malignancies, including chronic myelocytic leukemia. In the present study, a model for fibroblast-mediated HuIFN-alpha gene therapy for the treatment of chronic myelocytic leukemia is described. Human IFN-alpha 5 complementary DNA was inserted into a bovine papilloma virus plasmid vector (BMGNeo) containing a neomycin resistance gene. The recombinant plasmid (BMGNeo-IFN) was transfected into NIH/3T3 fibroblasts by the calcium phosphate coprecipitation method, and stably transformed cells were isolated by G418 selection. A fibroblast clone secreting a large amount of HuIFN into the culture supernatant was selected by radioimmunoassay using anti-HuIFN-alpha monoclonal antibodies. Southern blot analysis revealed that the transformed cells contained approximately ten copies of the BMGNeo-IFN plasmid per cell, and Northern blot analysis demonstrated high expression of HuIFN-alpha mRNA in the cells. This fibroblast clone strongly suppressed proliferation of a HuIFN-alpha-sensitive chronic myelocytic leukemia cell line (KU812) during cocultivation in vitro. When the HuIFN-alpha-producing fibroblasts were implanted into nude mice bearing KU812 tumors by the subcutaneous diffusion chamber method, tumor growth in vivo was also significantly suppressed. This study suggests the clinical potential of fibroblast-mediated gene therapy in the future.

Animals↗
PubMed1990

Human monocyte colony-stimulating factor enhances the clearance of lipoproteins containing apolipoprotein B-100 via both low density lipoprotein receptor-dependent and -independent pathways in rabbits.

To investigate the effects of recombinant human monocyte colony-stimulating factor (M-CSF) on plasma cholesterol metabolism, we injected M-CSF intravenously into New Zealand White rabbits (n = 13) at a dose of 100 micrograms/day for 7 days. After the treatment, the plasma cholesterol levels fell by 33.2% from 61.4 +/- 25.9 to 41.0 +/- 10.2 mg/dl (mean +/- S.D.). We also injected a large dose of M-CSF (500 micrograms/day) for 6 days into Watanabe Heritable Hyperlipidemic rabbits, which are deficient in low density lipoprotein (LDL) receptors. Again, there was a significant reduction in plasma cholesterol levels by 36.2% from 730.5 +/- 176.4 to 466.0 +/- 104.9 mg/dl (n = 4). In the kinetic studies in New Zealand White rabbits with very low density lipoprotein, LDL, and methylated LDL, the removal rates of those lipoproteins were increased 1.9-, 1.7-, and 2.0-fold, respectively, after the treatment. Immunoblot analysis of LDL receptors in the treated rabbits showed no significant changes in LDL receptor proteins in livers but a great increase in spleens and bone marrows compared with the controls. Messenger RNA was also estimated by Northern blotting in both groups, and the results were compatible with those from the immunoblot. The data suggest that M-CSF stimulates the clearance of lipoproteins containing apolipoprotein B-100 via both LDL receptor-dependent and -independent pathways in target cells of M-CSF and reduces plasma cholesterol.

Animals↗
PubMed1990

Insulin enhancer binding protein has helix-loop-helix structure.

Insulin gene expression is restricted to pancreatic B cells and the 5' flanking region is responsible for the tissue specificity. The GCCATCTG motif in this region of the rat insulin 1 gene functions as an enhancer for insulin transcription. A cDNA coding for a GCCATCTG motif-binding protein (IEBP1) was isolated from a rat pancreatic B cell tumor lambda gt11 library. The IEBP1 protein was found to be the rat counterpart of the immunoglobulin (Ig) enhancer binding protein E12/47 having a helix-loop-helix domain. This result indicates that the Ig gene and insulin gene employ the same (or a similar) binding protein as a part of their transcriptional apparatus.

Amino Acid Sequence↗
PubMed1990

C-terminal truncated glucose transporter is locked into an inward-facing form without transport activity.

The facilitated glucose transporters comprise a structurally related family of proteins predicted to have 12 membrane-spanning domains, with the amino terminus, a relatively large middle loop and the carboxy-terminus all oriented towards the cytoplasm. An alternating conformation model has been proposed to explain the mechanism of facilitated glucose transport. To understand the structure-function relationships, especially the role of the intracellular C-terminal domain, we have modified the rabbit equivalent of the erythroid-type transporter, GLUT1 (ref. 18), using complementary DNA to code for a deletion mutant that lacks most (37 out of 42 amino acids) of the intracellular C-terminal domain. This deletion mutant is expressed at the cell surface of Chinese hamster ovary (CHO) cells, but is functionally inactive, probably because it has lost its capacity to alternate in conformation and so is locked into an inward-facing form.

Animals↗
PubMed1990

Immunological quantitation and immunohistochemical localization of leukotriene A4 hydrolase in guinea pig tissues.

We prepared a highly specific polyclonal antibody against leukotriene (LT) A4 hydrolase using a recombinant human enzyme. Using this antibody, we quantified LTA4 hydrolase protein content in the cytosols of guinea pig tissues. The enzyme protein content correlated well with the enzyme activity with a correlation coefficient of 0.87. However, the enzyme activity per mg of the enzyme in the cytosols was low, particularly in the liver and adrenal gland, compared with the specific activity of the purified enzyme. These observations suggest the presence of inhibitory substances and/or inactive enzymes in the cytosols of these tissues. To determine the cellular localization of LTA4 hydrolase in tissues other than blood cells, we carried out immunohistochemical examinations of guinea pig tissues. We identified epithelial cells in the tracheobronchial system and gastrointestinal tract, smooth muscle cells in the bronchi and aorta, vascular endothelial cells, and the intestinal plexus as novel cellular sources of the enzyme in the parenchyme of the tissue. Thus, LTA4 hydrolase was widely distributed in various types of parenchymal cells in the tissues, and this observation warrants further investigations on the biological activities of LTB4 in these cells and tissues.

Animals↗
PubMed1990

Concanavalin A-induced receptor aggregation stimulates the tyrosine kinase activity of the insulin receptor in intact cells.

Concanavalin A (ConA) stimulated the phosphorylation of the beta-subunit of the insulin receptor and an Mr-185,000 protein on serine and tyrosine residues in intact H-35 rat hepatoma cells. This Mr-185,000 protein whose phosphorylation was stimulated by ConA was identical to pp185, a protein reported previously to be a putative endogenous substrate for the insulin receptor tyrosine kinase in rat hepatoma cells. In Chinese hamster ovary (CHO) cells transfected with cDNA of the human insulin receptor, tyrosine-phosphorylation of pp185 was strongly enhanced by ConA compared with the controls, suggesting that the induction of tyrosine-phosphorylation of pp185 was due to stimulation of the insulin receptor kinase by ConA. Moreover, monovalent ConA only slightly induced the tyrosine-phosphorylation of pp185, which was enhanced by the addition of anti-ConA IgG, suggesting that ConA stimulated the insulin receptor kinase mainly by the receptor cross-linking or aggregation in intact cells. These data suggest that the insulin-mimetic action of ConA is related to the autophosphorylation and activation of the insulin receptor tyrosine kinase, as well as the subsequent phosphorylation of pp185 in intact cells.

Animals↗
PubMed1990

Atrial natriuretic peptide and vasopressin during percutaneous transvenous mitral valvuloplasty and relation to renin-angiotensin-aldosterone system and renal function.

To study the relation between plasma atrial natriuretic peptide (ANP) and cardiac pressure, and to assess the pathophysiologic significance of ANP in water and electrolyte metabolism, the changes in plasma levels of ANP and arginine vasopressin (AVP) were examined in 11 patients with mitral stenosis who underwent percutaneous transvenous mitral valvuloplasty, and compared with the changes in the renin-angiotensin-aldosterone system and renal function. Immediately after valvuloplasty, plasma ANP levels decreased significantly with a concomitant decrease in mean pressures in the left atrium, the pulmonary artery and the right atrium. Plasma ANP levels decreased to the normal range in 4 of the 6 patients with normal sinus rhythm, while all 5 patients with atrial fibrillation had higher levels despite a similar degree of decrease in atrial pressure. There were significant positive correlations between plasma ANP levels and the mean left atrial pressure (r = 0.61, p less than 0.01), the mean pulmonary arterial pressure (r = 0.49, p less than 0.01) and the mean right atrial pressure (r = 0.54, p less than 0.01). The mean plasma AVP levels, on the other hand, showed a transient increase after valvuloplasty from 0.5 +/- 0.1 to 1.2 +/- 0.4 pg/ml (p less than 0.05). The mean plasma renin activity (1.3 +/- 0.3 vs 2.7 +/- 0.8 ng/ml/hr, p less than 0.05) and plasma aldosterone concentration (8.6 +/- 2.3 vs 17.2 +/- 5.2 ng/dl, p less than 0.05) also increased significantly 30 minutes after valvuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Stretching cardiac myocytes stimulates protooncogene expression.

Recently cellular protooncogenes have been found to be induced as an early response to pressure overload in cardiac hypertrophy. To examine whether mechanical stimuli directly induce specific gene expression in the heart, we cultured rat neonatal cardiocytes in elastic silicone dishes and stretched these adherent cells. Myocyte stretching stimulated expression of the protooncogene, c-fos, in a stretch length-dependent manner, followed by an increase in amino acid incorporation into proteins. c-fos mRNA levels were enhanced within 15 min by cardiocyte stretching, peaked at 30 min, and declined to undetectable levels by 240 min. In the presence of cycloheximide, a greater increase in c-fos mRNA was seen by stretching. The transfected chloramphenicol acetyltransferase gene linked to upstream sequences of the fos gene including its promoter was also activated by stretching cardiac myocytes. These results suggest that mechanical loading directly regulates gene transcription without the participation of humoral factors in cardiocytes.

Animals↗
PubMed1990

Latent form of transforming growth factor-beta 1 acts as a potent growth inhibitor on a human erythroleukemia cell line.

Recombinant latent form of transforming growth factor-beta 1 (L-TGF-beta 1) is activated by various chemical treatments, including acidification and heating. However, cellular mechanisms that release transforming growth factor-beta (TGF-beta) in an active form have not been fully elucidated. Investigated herein are the effects of L-TGF-beta 1 on various leukemic cell lines. Heat-activated L-TGF-beta 1 inhibited colony formation of U937, KG-1 and HL-60, whereas untreated L-TGF-beta 1 had only a marginal effect on these cells. In contrast, colony formation of human erythroleukemia cell line (HEL) was markedly inhibited by both heat-activated and untreated L-TGF-beta 1. In vitro incubation of L-TGF-beta 1 with HEL cells did not release the active form in the culture supernatants. These results suggest that HEL cells are capable of activating L-TGF-beta 1, but only in a cell-associated manner. Since HEL cells produce L-TGF-beta 1, it may act as an autocrine negative growth factor on these cells.

Animals↗
PubMed1990

Apolipoprotein E and lipoprotein lipase secreted from human monocyte-derived macrophages modulate very low density lipoprotein uptake.

We investigated the roles of lipoprotein lipase and apolipoprotein E (apoE) secreted from human monocyte-derived macrophages in the uptake of very low density lipoproteins (VLDL). ApoCII-deficient VLDL were isolated from a patient with apoCII deficiency. The lipolytic conversion to higher density and the degradation of the apoCII-deficient VLDL by macrophages were very slight, whereas the addition of apoCII enhanced both their conversion and degradation. This suggests that the lipolysis and subsequent conversion of VLDL to lipoproteins of higher density are essential for the VLDL uptake by macrophages. VLDL incubated with macrophages obtained from subjects with E3/3 phenotype (E3/3-macrophages) showed a 17-fold greater affinity in inhibiting the binding of 2 micrograms/ml 125I-low density lipoprotein (LDL) to fibroblasts than native VLDL, whereas the incubation of VLDL with macrophages obtained from a subject with E2/2 phenotype (E2/2-macrophages) did not cause any increase in their affinity. Furthermore, 3 micrograms/ml 125I-VLDL obtained from a subject with E3/3 phenotype were degraded by E3/3-macrophages to a greater extent than by E2/2-macrophages (2-fold), indicating that VLDL uptake is influenced by the phenotype of apoE secreted by macrophages. From these results, we conclude that both lipolysis by lipoprotein lipase and incorporation of apoE secreted from macrophages alter the affinity of VLDL for the LDL receptors on the cells, resulting in facilitation of their receptor-mediated endocytosis.

Apolipoprotein C-II↗
PubMed1990

Susceptibility of human erythropoietic cells to B19 parvovirus in vitro increases with differentiation.

B19 human parvovirus is the etiologic agent of transient aplastic crisis. To better understand B19 virus-induced hematopoietic suppression, we studied the host cell range of the virus using in vitro bone marrow cultures. First, B19 virus replication was examined in the presence of various purified cytokines using DNA dot blot analysis. Replication was detected only in erythropoietin-containing cultures. The other cytokines (granulocyte/macrophage colony-stimulating factor [GM-CSF], G-CSF, M-CSF, interleukin-1 [IL-1], IL-2, IL-3, and IL-6) did not support virus replication, indicating the restriction of B19 virus replication to the erythroid cell lineage. Second, hematopoietic progenitor cells were serially assayed in B19-infected and uninfected bone marrow cultures. At initiation, B19 virus infection caused marked and moderate reduction in colony-forming unit erythroid (CFU-E) and burst-forming unit erythroid (BFU-E) numbers, respectively, without affecting CFU-Mix and CFU-GM numbers. Interestingly, the recovery of the erythroid progenitor numbers was observed at a late stage of cultures despite the sustained reduction in erythroblasts. The cells in the bursts derived from such reappearing BFU-E did not contain the virus genome. Although infectious virus was detected in the culture supernatants, the cultured CFU-E harvested at day 5 was relatively resistant to B19 virus infection compared with the CFU-E in fresh bone marrow. These findings suggest that pluripotent stem cells escaped B19 virus infection and restored the erythroid progenitor cells later in infected cultures. We conclude that the target cells of B19 virus are in the erythroid lineage from BFU-E to erythroblasts, with susceptibility to the virus increasing along with differentiation. Furthermore, the suppression of erythropoiesis and the subsequent recovery of the erythroid progenitor numbers in B19-infected liquid cultures may be analogous in part to the clinical features of B19 virus-induced transient aplastic crisis.

Biological Factors↗
PubMed1990

Interleukin 1 increases the production of endothelin-1 by cultured endothelial cells.

We examined the effect of human recombinant interleukin 1 (IL-1) on the production of endothelin-1 by cultured porcine endothelial cells. The induction of endothelin-1 mRNA began within 1 hr of exposure to IL-1, showed twin peaks at 4 and 24 hr, and declined thereafter. Enzyme-linked immunosorbent assay revealed that the amount of endothelin-1 peptide in conditioned media was also increased by IL-1 in a dose- and time-dependent manner. Our results suggested that IL-1, a macrophage-derived cytokine, may affect the contraction and proliferation of vascular smooth muscle cells by stimulating the production of endothelin by endothelial cells.

Animals↗
PubMed1990

Granulocyte colony-stimulating factor stimulates human mature neutrophilic granulocytes to produce interferon-alpha.

Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein hormone that specifically stimulates both production and functional activation of neutrophils, while interferon-alpha (IFN-alpha) is known to suppress myelopoiesis, including neutrophil production in vivo and in vitro. On a possibility that IFN-alpha may operate as one of the inhibitory feedback factors in neutropoiesis, we examined whether neutrophils produce IFN-alpha in response to G-CSF. Northern blot analysis showed that messenger RNA (mRNA) for human IFN-alpha 1 became detectable time-dependently in highly purified human neutrophils incubated with purified recombinant human G-CSF (rhG-CSF). But such transcription was not observed either in neutrophils incubated with other neutrophil activators, such as formyl-methionyl-leucyl-phenylalanine (fMLP) or lipopolysaccharides (LPS), or in blood mononuclear cells incubated with rhG-CSF. In addition, radioimmunoassay for human IFN-alpha showed that its levels in culture medium of the rhG-CSF-treated neutrophils rose markedly (up to approximately 100 IU/mL/1 x 10(7) cells) in a time-dependent way, compared with those of nonstimulated neutrophils. These findings suggest that the G-CSF/IFN-alpha system may participate in the feedback regulatory loop of neutropoiesis.

Blotting, Northern↗
PubMed1990

Patient with pyruvate kinase deficiency developed acute myelogenous leukemia.

A 44-year-old previously healthy male was diagnosed as anemic and treated at a nearby hospital. A year later, he was admitted to our hospital for precise examination of the progression of refractory anemia. Blood examination showed hemolytic anemia and more detailed examination of this hemolysis revealed pyruvate kinase deficiency. The activity was 15.1% of a normal control. Pyruvate kinase activities of his family members were normal or slightly decreased. Ten months after admission to our hospital, 2% of blast cells with Auer's body in the peripheral blood were noted which increased progressively. The bone marrow contained 17.3% of blast cells with a subsequent diagnosis of acute myelogenous leukemia being made. Although intensive chemotherapy was performed, the patient achieved a brief remission and died 2 years after admission to our hospital.

Adult↗
PubMed1990

Intracellular assembly of newly synthesized canine cardiac myosins.

To investigate how newly synthesized cardiac myosins are assembled into myofilaments, we analysed the distribution of newly produced alpha-myosin heavy chain isozyme in sarcomeres by immunoelectron microscopy using a monoclonal antibody (CMA19), which is specific for alpha-myosin heavy chain. Isozymic changes in myosin heavy chains from beta to alpha type were induced in canine ventricular muscles and cultured ventricular myocytes by administration of 1-thyroxine. We incubated the glycerinated ventricular muscles or cultured ventricular myocytes with the enzyme (horseradish peroxidase) labelled Fab fragment of CMA19. After the reaction with 3, 3'-diaminobenzidine and osmification, we prepared ultrathin sections of the ventricular muscles or cultured ventricular myocytes and analysed their staining patterns by electron microscopy. There was apparent heterogeneity in the staining intensity of the myofilaments among different cells, among different myofibrils and even intramyofibrillarly. Higher magnification revealed that there were scattered foci of strong reaction which appeared to be foci of assembly of the newly synthesized alpha-myosin heavy chain. Immunocytochemical study also showed heterogeneous reactions within myofilaments and that there were scattered foci of myofilament assembly, which were closely associated with polyribosomes producing newly induced alpha-myosin heavy chain. These data suggest that newly synthesized cardiac myosins are assembled into myofilaments from the sites of synthesis, that is polyribosomes. This may explain the heterogeneity of the assembly pattern of newly synthesized cardiac myosins at the subcellular level.

Actin Cytoskeleton↗
PubMed1990

Frequent expression of receptors for granulocyte-macrophage colony-stimulating factor on human nonhematopoietic tumor cell lines.

Receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF) were identified on 9 of 35 (26%) human nonhematopoietic tumor cell lines including non-small cell lung cancer, stomach cancer, colon cancer, and osteosarcoma cells. GM-CSF receptors distributed on these human tumor cells were low affinity types with an equilibrium dissociation constant of 1.5-10.0 nM. Cross-linking studies revealed that the molecular weights of the low affinity GM-CSF receptors were 65-85 kilodaltons. The high affinity receptors identified on hematopoietic cells were not detected on human nonhematopoietic tumor cells which we studied, and we could detect no effects of GM-CSF on cell growth of these tumor cells.

Carcinoma, Non-Small-Cell Lung↗