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M Shiozaki

Publications and source records attributed to M Shiozaki.

At least 37 records · Page 2Linked to original sources
PubMed1992

Evidence for the participation of endogenous activin A/erythroid differentiation factor in the regulation of erythropoiesis.

Activin A/erythroid differentiation factor (EDF) is a human protein that induces differentiation of a murine erythroleukemia cell (the Friend cell). In this study, we demonstrate that endogenous activin A/EDF activity is present in murine bone marrow and spleen. In addition, this activity is secreted by bone marrow and spleen cells in primary culture. Administration of follistatin (a specific binding protein for activin A/EDF) to mice results in a decrease of erythroid progenitors in the bone marrow and spleen. These findings support the concept that activin A/EDF and follistatin have opposing actions in the regulation of erythropoiesis.

Activins↗
PubMed1992

The existence of activin A/erythroid differentiation factor and its inhibitor in human serum: comparison of normal and chronic renal failure sera.

Activin A/EDF, initially found as a differentiation inducer of murine Friend erythroleukemia, also has a stimulatory effect on erythropoiesis in vitro and in vivo. Here we proved activin A/EDF activity in human serum. The activin A/EDF level in 18 normal human serum samples was measured by a specific bioassay and was found to be 8.3 +/- 4.6 ng/ml, indicating that there exists sufficient activity to affect erythropoiesis in normal serum. In contrast, activin A/EDF activity was reduced in the chronic renal failure patients and 23/26 serum samples examined showed levels below 1.2 ng/ml. Further analysis using HPLC revealed that chronic renal failure serum actually contained as much activin A/EDF as normal serum, and that the difference between normal and patient serum existed in the content of a specific inhibitor of activin A/EDF. This observation suggests the possibility that the inhibitor is participating in the regulation of activin A/EDF activity in vivo in chronic renal failure patients and also the possibility of activin A/EDF could be utilized in the therapy of the anemia of such patients.

Activins↗
PubMed1992

Intercellular junctions in embryonic chick cardiac muscle revealed by rapid freezing and freeze-substitution.

Using the method of rapid freezing and freeze-substitution, the embryonic chick cardiac muscle was investigated by transmission electron microscopy. Initially, the intercellular junctional complexes (fasciae adherentes and desmosomes) were formed in close proximity to each other along a nearly straight line. Subsequently, the separation of fasciae from desmosomes took place to form intercalated discs. The cell membranes of fasciae adherentes were reinforced with highly interwoven fine fibrils at which myofibrils terminated. The intercellular space of fasciae was bridged with fine fibrillar structures seemingly connected by a thin line at their middle portions. In the intercellular space of desmosomes, central lamina and traversing filaments were clearly observed. The outer and inner leaflets of the desmosomal plasmalemma were asymmetrically differentiated; the outer leaflet was thinner than the inner leaflet. On the inner side of the cell membrane, an electron-lucent layer and a dense desmosomal plaque were observed. The latter structure had protrusions with less electron density towards the cytoplasmic side. Further inside, a meshwork of fine fibrils was seen along and toward which bundles of intermediate filaments ran. The results obtained with freeze-substitution appeared to provide more information than those with thin sections after conventional fixation or with replicas of chemically fixed/glycerinated or physically fixed/deep-etched materials.

Animals↗
PubMed1992

[Function, molecular structure and gene expression regulation of erythroid differentiation factor (EDF/activin A)].

Erythroid differentiation factor (EDF), initially found as a differentiation inducer of murine erythroleukemia cells, also acts on normal erythroid progenitors in vitro and in vivo. Furthermore, it is produced endogenously and supporting in vivo erythropoiesis. EDF is structurally identical to activin A, a gonadal protein with follicle stimulating hormone releasing activity, and belongs to TGF beta superfamily. Its activity could be regulated by follistatin, a binding protein with neutralizing activity against EDF/activin A. Molecular cloning of EDF/activin A receptor cDNA has revealed its domain structure characteristic to serine/threonine kinase.

Activin Receptors↗
PubMed1991

Effect of erythroid differentiation factor on megakaryocytic differentiation of L8057, a murine megakaryoblastic leukemia cell line.

To assess the potent effect of erythroid differentiation factor (EDF) on megakaryocytopoiesis, effect of EDF on megakaryocytic differentiation of L8057, a murine megakaryoblastic cell line, was examined. EDF potentiated AchE induction of L8057 in a dose dependent manner. The potency of EDF on megakaryocytic differentiation is comparable to that on erythroid differentiation reported previously. The present results suggest that EDF may play a regulatory role in megakaryocytopoiesis as well as in erythropoiesis.

Acetylcholinesterase↗
PubMed1991

Synthesis of a 3-ether analogue of lipid A.

Lipid A 3-ether analogues were synthesized from allyl 2-deoxy-4,6-O-isopropylidene-2-trifluoroacetamido-alpha-D-glucopyr anoside and 3,4,6-tri-O-acetyl-2-trifluoroacetamido-alpha-D-glucopyranosyl bromide. The compound lost completely the endotoxic activity.

Animals↗
PubMed1991

Synthesis of 2-deoxy-2-[(2,2-difluoro-3-hydroxytetradecanoyl)amino]-3-O- [(R)-3-(tetradecanoyloxy)tetradecanoyl]-D-glucopyranose 4-phosphate.

2-Deoxy-2-[(2,2-difluoro-3-hydroxytetradecanoyl)amino]-3-O-[(R)-3- (tetradecanoyloxy)tetradecanoyl]-D-glucopyranose 4-phosphates (9H,L) were synthesized from allyl 2-amino-2-deoxy-4,6-O- isopropylidene-beta-D-glucopyranoside (1), (+/-)-3-[(benzyloxycarbonyl)oxy]-2,2-difluorotetradecanoic acid, and (R)-3- (tetradecanoyloxy)tetradecanoic acid. Both compounds 9H and 9L were more active than GLA-60 for the prostaglandin D2 releasing test on macrophages.

Animals↗
PubMed1990

Differentiation-inducing and growth-inhibitory activities of erythroid differentiation factor (EDF/activin A) toward mouse erythroleukemic cells in vivo.

The in vivo differentiation-inducing activity of a purified human erythroid differentiation factor (EDF) toward mouse erythroleukemic cells (MEL cells) was examined. BDF1 mice with diffusion chambers implanted in the peritoneal cavity were treated with continuous i.p. administration of EDF. MEL cells within a diffusion chamber differentiated into hemoglobin-positive cells when treated with EDF, the percentage of the positive cells being 32.3 +/- 28.3 on day 5 as compared to 0.2 +/- 0.3 in the controls. The anti-tumor activity of EDF was also examined in a nude mouse MEL solid tumor model. Daily intra-tumor treatment with EDF for 10 days resulted in 73% suppression of tumor growth on day 25. A histological study revealed that EDF-treated solid tumor cells became hemoglobin-positive, indicating the anti-tumor activity of EDF through induction of differentiation in vivo. EDF could induce in vitro the differentiation of human erythroleukemic cell lines K562 and HEL, as well as the murine cell line. These results indicate the possibility of differentiation therapy for erythroleukemia using EDF.

Activins↗
PubMed1990

Proliferation and differentiation of erythroleukemia cell line (ELM-I-1) in response to erythropoietin and interleukin 3.

Here we describe the characterization of Epo-responsive mouse erythroleukemia cell line ELM-I-1. ELM-I-1 cells possess Epo binding sites on their membranes and differentiate into hemoglobin-positive cells when cultured in the presence of Epo. About 20% of the cells were hemoglobin-positive after a 3- to 4-day exposure to recombinant human Epo in liquid culture. Supplementation of recombinant mouse IL-3 during culture had an augmentative effect on Epo-mediated differentiation, although IL-3 alone did not induce differentiation. Both Epo and IL-3 stimulated the growth of ELM-I-1 cells, and their effects were a slightly additive. These findings indicate that ELM-I-1 cells are suitable for studying the interaction between Epo and IL-3 in erythroid differentiation at a subcellular level. ELM-I-1 may also offer a valuable bioassay system for Epo.

Animals↗
PubMed1990

Three-dimensional structure of intracellular membranous organelles in embryonic chick skeletal muscle cells in vitro revealed with scanning electron microscope.

Using the freeze-polishing and osmium-maceration procedures, the ultrastructure of intracellular membranous organelles in embryonic chick skeletal muscle cells in vitro was investigated three-dimensionally with the scanning electron microscope (SEM). T-system tubules followed a tortuous course and possessed many warts. Some of these tubules could be traced to the sarcolemma. The sarcoplasmic reticulum (SR) had elaborate structures of a hexagonal pattern. By comparing the SEM images with those of ultrathin sections of myotubes impregnated with ferritin particles, the distinction between the T-system and SR was confirmed. Late in the culture, these two intracellular membranous systems were arranged periodically at right angles to the longitudinal axis of the myotubes. Round-shaped mitochondria were often arranged in chains connected with slender rods. Long rod-shaped mitochondria exhibited occasional branchings.

Animals↗
PubMed1989

In vivo treatment with erythroid differentiation factor (EDF/activin A) increases erythroid precursors (CFU-E and BFU-E) in mice.

The in vivo effect of human EDF on erythroid precursors (CFU-E and BFU-E) was investigated in normal and bled mice. In anemic (bled) mice, EDF treatment led to significant dose-dependent rises in the CFU-E and BFU-E levels of bone marrow. An elevation in the level of CFU-E was also seen in the spleen. In normal mice, a significant elevation in the level of bone marrow BFU-E was observed. Thus, EDF has an effect on erythropoiesis in anemic and normal mice in vivo.

Activins↗
PubMed1989

Formation of lambda transducing phage in vitro: involvement of DNA gyrase.

We found that transducing phages carrying the gal or bio regions of the Escherichia coli genome were formed during in vitro packaging of endogenous lambda DNA. Structural analysis of the transducing phage genomes indicated that they were formed by abnormal excision of lambda prophage. Formation of transducing phages was stimulated by oxolinic acid, an inhibitor of DNA gyrase, implying that DNA gyrase participates in the abnormal excision of lambda prophage. When pBR322 DNA was added to the reaction mixture, transducing phages into which pBR322 had been inserted were produced at a high frequency. This reaction was also stimulated by oxolinic acid. Sequence analyses revealed that pBR322 is inserted into the sites of abnormal excision of the prophage. These results show that transducing phages can be formed by DNA gyrase-dependent illegitimate recombination in an in vitro system and that secondary recombination takes place frequently at the site where the first recombination occurs.

Bacteriophage lambda↗
PubMed1987

The complete amino acid sequence of rice bran trypsin inhibitor.

The complete amino acid sequence of a double-headed trypsin inhibitor (RBTI) from rice bran was determined by a combination of limited proteolysis of the native inhibitor with Streptomyces griseus trypsin at pH 3 and conventional methods. RBTI consists of 133 amino acid residues including 18 half-cystine residues which are involved in 9 disulfide bridges in the molecule. The limited proteolysis at pH 3 produced a major split of Lys(83)-Met(84) and a minor split of Arg(107)-Val(108) together with a non-enzymatic hydrolysis of Asp(19)-Pro(20) in the molecule. The established sequence showed that RBTI is composed of 4 domains, domains I and III, and domains II and IV being homologous to the first and the second domains of soybean Bowman-Birk inhibitor, respectively, indicating that RBTI has a duplicated structure of the Bowman-Birk type inhibitor.

Amino Acid Sequence↗
PubMed1987

Myogenesis in vitro as seen with the scanning electron microscope.

In this paper, we review our recent observations by scanning electron microscopy (SEM) on the differentiation of the cell surface and cytoplasmic organelles in embryonic chick skeletal muscle cells in vitro. The changes of the surface structures of myoblasts during mitosis were essentially similar to those of other cell types, but the characteristic spindle shape of myoblasts did not change throughout most of this period. Cytoskeletal structures under the sarcolemma were examined by Triton extraction and metal coating. Cells in S, G2 and M possessed a dense, and those in G1 a loose filament network under the membrane. Myotubes possessed a dense network under the sarcolemma. In the fusion area between a myoblast and a myotube, the cytoskeletal domain of the former could be distinguished from the latter because of the mosaic appearance of the subsarcolemmal cytoskeletal network. This network was composed predominantly of 10-13 nm filaments; they were identified as actin filaments because of their decoration with myosin subfragment-1. Triton treatment and thiocarbohydrazide-osmium staining allowed us to visualize myofibrils. They ran in the direction of inferred stress lines brought about by elongation and adhesion of the cells to substrate. Intracellular membranous organelles could be seen by the freeze-polishing and osmium-maceration procedure. Mitochondria exhibited complex irregular branchings. T system tubules ran a tortuous course. Sarcoplasmic reticula with occasional dilatations were connected to each other. The results are of sufficient promise to encourage more extensive analysis of myogenesis by SEM.

Animals↗