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Biomedical subjects

T Furusawa

Publications and source records attributed to T Furusawa.

At least 37 records · Page 2Linked to original sources
PubMed1999

A novel stromal cell-dependent hematopoietic cell line established from temperature-sensitive SV40 T-antigen transgenic mice.

A novel primitive hematopoietic cell line, THS119, was established from lineage marker negative (Lin-)/Sca-1+ cells from bone marrow of temperature-sensitive (ts) SV40 T-antigen transgenic mice after lengthy passaging by coculture with TBR59 bone marrow stromal cells. THS119 cells exhibited immature primitive hematopoietic cells such as forming cobblestones underneath the stromal cell layers. They retained properties of hematopoietic stem cells as shown by expression of c-Kit, Sca-1 and CD34low, but lacked hematopoietic lineage surface markers of differentiated hematopoietic cells (Gr-1, TER119, Mac-1, CD3, B220). RT-PCR analysis showed that THS119 cells exhibited multiple expression of both earlier developmental markers of myeloid, lymphoid and the hematopoietic cell specific transcription factors. THS119 cells showed temperature-dependent growth reflecting ts T-antigen, and their maintenance was TBR59 stromal cell-dependent. The requirement of stromal cells could not be replaced by cytokines, however, an IL-3 or IL-7 dependent cell line was generated after prolonged culture of THS119 cells on the stromal cells in the presence of these cytokines, and these cytokine-dependent cell lines exhibited phenotypes similar to the parental cells in their gene expression. SCF/c-Kit interaction is one factor required for their maintenance, but involvement of other factor(s) in the conditioned medium of TBR59 stromal cells was suggested. A novel immature hematopoietic cell line, THS119, may provide an appropriate experimental system to resolve how hematopoietic cells are kept in a primitive phase within a hematopoietic microenvironment.

Animals↗
PubMed1999

Cloning and sequence of a cDNA for a highly basic protease from the digestive juice of the silkworm, Bombyx mori.

A serine protease of the silkworm, Bombyx mori, with an isoelectric point of pH 10-11 and a pH optimum for succinyl-Leu-Leu-Val-Tyr-MCA degrading activity of about 10, was found in a 0.33 M NaCl-eluted fraction obtained from cation-exchange chromatography of digestive juice. The activity of the enzyme was strongly inhibited by chymostatin and PMSF, indicating that the protease is a chymotrypsin-like serine protease. The N-terminal amino acid sequence of the protease was determined, and a full-length cDNA clone (0.92 kbp) which was isolated from a midgut cDNA library was sequenced. The cDNA encodes a pre-proenzyme of 284 amino acids with a pro-segment of 50 amino acids and mature protein of 234 amino acids. From its primary structure, the predicted molecular mass of the mature protein is 24.5 kDa. A sequence comparison of the Bombyx highly basic protease with other serine proteases revealed that this enzyme is a mammalian-type serine protease with a catalytic triad consisting of His45, Asp92 and Ser186. A large number of Arg residues are encoded by the cDNA which may be responsible for its stability and/or function in the alkaline condition, by remaining charged at high pH.

Amino Acid Sequence↗
PubMed1999

Identification of CtBP1 and CtBP2 as corepressors of zinc finger-homeodomain factor deltaEF1.

deltaEF1, a representative of the zinc finger-homeodomain protein family, is a transcriptional repressor which binds E2-box (CACCTG) and related sequences and counteracts the activators through transrepression mechanisms. It has been shown that the N-proximal region of the protein is involved in the transrepression. Here we demonstrate that deltaEF1 has a second mechanism of transrepression recruiting CtBP1 or CtBP2 as its corepressor. A two-hybrid screen of mouse cDNAs with various portions of deltaEF1 identified these proteins, which bind to deltaEF1 in a manner dependent on the PLDLSL sequence located in the short medial (MS) portion of deltaEF1. CtBP1 is the mouse orthologue of human CtBP, known as the C-terminal binding protein of adenovirus E1A, while CtBP2 is the second homologue. Fusion of mouse CtBP1 or CtBP2 to Gal4DBD (Gal4 DNA binding domain) made them Gal4 binding site-dependent transcriptional repressors in transfected 10T1/2 cells, indicating their involvement in a transcriptional repression mechanism. When the MS portion of deltaEF1 was used to Gal4DBD and used to transfect cells, a strong transrepression activity was generated, but this activity was totally dependent on the PLDLSL sequence which served as the site for interaction with endogenous CtBP proteins, indicating that CtBP1 and -2 can act as corepressors. Exogenous CtBP1/2 significantly enhanced transcriptional repression by deltaEF1, and this enhancement was lost if the PLDLSL sequence was altered, demonstrating that CtBP1 and -2 act as corepressors of deltaEF1. In the mouse, CtBP1 is expressed from embryo to adult, but CtBP2 is mainly expressed during embryogenesis. In developing embryos, CtBP1 and CtBP2 are expressed broadly with different tissue preferences. Remarkably, their high expression occurs in subsets of deltaEF1-expressing tissues, e.g., cephalic and dorsal root ganglia, spinal cord, posterior-distal halves of the limb bud mesenchyme, and perichondrium of forming digits, supporting the conclusion that CtBP1 and -2 play crucial roles in the repressor action of deltaEF1 in these tissues.

Alcohol Oxidoreductases↗
PubMed1998

Nuclear receptor binding factor-1 (NRBF-1), a protein interacting with a wide spectrum of nuclear hormone receptors.

To identify the proteins which may modulate the functions of peroxisome proliferator-activated receptor (PPAR), a rat liver cDNA library was screened by a yeast two-hybrid system, using the mouse PPARalpha as a bait. A protein named nuclear receptor binding factor-1 (NRBF-1) was identified, which interacts not only with PPARalpha, but also with various nuclear hormone receptors in the presence of the respective ligands. Both the hinge and ligand-binding domains of PPARalpha are required for the interaction. NRBF-1 seems to be translocated to the nucleus by a piggyback mechanism, together with PPARalpha. NRBF-1 has a significant homology to the yeast protein MRF1, a putative transcription factor regulating the expression of mitochondrial respiratory proteins. NRBF-1 might be another type of nuclear receptor co-operator.

Amino Acid Sequence↗
PubMed1998

MRI of enlarged endolymphatic sacs in the large vestibular aqueduct syndrome.

We studied ten inner ears of five patients with a bilateral large vestibular aqueduct syndrome, using CT and MRI. Although the large vestibular aqueduct varied in size, a markedly dilated endolymphatic sac extending to the sigmoid sinus was demonstrated bilaterally on MRI in all patients. The cause of hearing loss in this syndrome is unclear. However, it is suggested that reflux of the protein-rich, hyperosmolar endolymph from the enlarged endolymphatic sac (EES) into the cochlea through a widely patent endolymphatic duct may damage the neuroepithelium. CT density and spin-echo MRI signal intensity of the endolymph in EES were markedly higher than those of CSF in eight inner ears of four patients. Increased density and high signal may indicate protein-rich, hyperosmolar endolymph. In some patients with sensorineural hearing loss and EES, the vestibular aqueduct may not appear dilated on CT. MRI is therefore necessary for correct diagnosis of this syndrome, which should more correctly be termed "large endolymphatic duct and sac syndrome". Prominent EES may predict poor prognosis in this syndrome.

Adolescent↗
PubMed1998

Integrin-associated protein (IAP, also termed CD47) is involved in stroma-supported erythropoiesis.

Erythropoiesis is regulated by the hematopoietic microenvironment of the spleen, fetal liver, and bone marrow in mice. We previously showed that established stromal cells from these organs selectively support erythropoiesis in vitro. To identify the cell surface molecule(s) on the stromal cells involved in erythropoiesis, we raised monoclonal antibodies (MAbs) to MSS62 stromal cells derived from newborn spleen and obtained MAb100.1, which partially inhibited the stroma-supported erythropoiesis in vitro. Using an expression cDNA library of MSS62 cells, we cloned a gene encoding the protein recognized by MAb100.1 and identified it as integrin-associated protein (IAP, also termed CD47), which may play a general role in integrin-mediated signal transduction. IAP/CD47 is expressed in the stromal cells of spleen, fetal liver, and bone marrow, and in a variety of hematopoietic cells including erythroblasts. Thus, IAP may be partly involved in the erythropoietic supporting ability of the stromal cells.

Amino Acid Sequence↗
PubMed1998

Reversible hyperintensity of the anterior pituitary gland on T1-weighted MR images in a patient receiving temporary parenteral nutrition.

We report a patient with severe anorexia nervosa, treated with temporary total parenteral nutrition (TPN), in whom reversible hyperintensity of the anterior pituitary gland was seen on T1-weighted MR images. The anterior pituitary was isointense with white matter before TPN therapy and became markedly hyperintense after 3 months of treatment. The intensity normalized after TPN therapy was discontinued. The transient hyperintensity was also seen in the basal ganglia and dorsal brain stem. We believe the hyperintensity of the anterior pituitary may be attributed to the TPN therapy.

Adolescent↗
PubMed1998

Focal orbital amyloidosis presenting as rectus muscle enlargement: CT and MR findings.

We report a case of focal orbital amyloidosis involving rectus muscles, which is an extremely rare clinical condition. CT scans showed rectus muscle enlargement with punctate calcifications. Heterogeneous hypointensity was present on T2-weighted MR images, and homogeneous enhancement was seen on fat-saturated contrast-enhanced images of the muscles. These imaging findings seem to be suggestive of amyloidosis. Focal amyloidosis should be included in the differential diagnosis of extraocular muscle enlargement.

Amyloidosis↗
PubMed1997

An orphan nuclear receptor lacking a zinc-finger DNA-binding domain: interaction with several nuclear receptors.

The yeast two-hybrid screening was applied to cloning cDNAs of proteins that interact with peroxisome proliferator-activated receptor alpha (PPAR alpha). We obtained from a rat liver cDNA library a clone encoding a protein related to the ligand-binding domain of the members of nuclear hormone receptor superfamily, whereas apparently lacking the zinc-finger DNA-binding domain. This protein interacted with the activated forms of several nuclear receptors, and thus is a novel type of heterodimer-forming nuclear receptor.

Amino Acid Sequence↗
PubMed1997

Solitary plasmacytomas of the occipital bone: a report of two cases.

The radiological appearances of two cases of solitary plasmacytoma in the occipital bone are described. One arose in the lateral part and the other in the squama. They showed characteristic radiological features on CT, MRI and angiography. Bone scintigraphy and gallium scintigraphy were also available. Solitary plasmacytoma of the skull is a rare condition and usually occurs in the calvarium. The skull base is an extremely rare site and only four cases have been reported. The literature of solitary plasmacytoma of the skull is reviewed.

Aged↗
PubMed1997

Osteoconductive properties and efficacy of resorbable bioactive glass as a bone-grafting material.

The height of the available bone between the alveolar ridge and the sinus is often insufficient for placing endosseous implants in the posterior maxilla. Subantral augmentation after sinus elevation can be performed using bone-grafting materials such as autogenous bone, allografts, and alloplasts. The properties and performance of a recently developed resorbable bioactive glass (BioGran) were investigated with regard to bioactivity and bone-forming capability. The bioactive glass was grafted into the sinus cavities of 25 patients and biopsies were taken after 7 months. The samples were examined by conventional histologic techniques, elemental composition and distribution assayed by an electron probe microanalyzer, and comparative biomechanical data for BioGran and bone tissue gathered. Histologic and biomechanical examination indicated bone formation in all cases, with biomechanical properties of the regenerated bone close to those of bone tissue. The results of this study suggest that BioGran exhibits osteoconductive properties and efficacy as an alloplastic bone-grafting material.

Biocompatible Materials↗
PubMed1997

Bone remodeling with resorbable bioactive glass and hydroxyapatite.

Particulate resorbable bioactive glass and resorbable hydroxyapatite did not inhibit the growth of periodontal ligament cells and osteoblasts in cultures. Both cell types promoted the activation of alkaline phosphatase around the surface of bioactive glass particles. When bioactive glass and hydroxyapatite were cultured with peripheral blood lymphocytes/monocytes, the number of nonadherent and adherent cells was the same as observed with a control. Resorbable bioactive glass activated the cells necessary for bone formation better than hydroxyapatite and suppressed the formation of osteoclasts for bone resorption. Resorbable bioactive glass and resorbable hydroxyapatite were found to be harmless to periodontium cells and lymphocytes/monocytes.

Absorption↗
PubMed1997

Large vestibular aqueduct syndrome with high CT density and high MR signal intensity.

We report a case of large vestibular aqueduct syndrome with a markedly dilated endolymphatic sac bilaterally. The density and signal intensity of the extraosseous portion of the sac were higher than those of cerebrospinal fluid on CT and MR studies. The findings may represent protein-rich and hyperosmolar fluid within the endolymphatic sac.

Adult↗
PubMed1997

[Open heart surgery without homologous blood transfusion for tetralogy of Fallot--use of hydroxyethyl starch diminishes the necessity of protein transfusion].

To avoid any blood or protein transfusions, we employed 6% hydroxyethyl starch in 0.9% saline (saline HES) during cardiopulmonary bypass (CPB) for intracardiac repair in 24 consecutive patients with Tetralogy of Fallot (TF). The postoperative course has been satisfactory (central venous pressure 9.5 +/- 1.2 cmH2O, duration of intubation after surgery 4.4 +/- 1.5 hours), and all patients but one did not require transfusion therapy during their hospital stay. We conclude that intracardiac repair without transfusions is feasible in almost all patients with TF, when substituting saline HES for blood or proteins.

Blood Proteins↗
PubMed1996

Development of fat within a meningioma.

We report a tentorial meningioma containing fat. Multiple areas of fatty density or intensity in the tumour were seen on CT and MRI, which corresponded histologically to lipomatous components. CT 10 years previously had demonstrated a smaller tumour without evidence of fatty components. We found only five cases in the literature in which fatty density was demonstrated within a meningioma on CT and a lipomatous component histologically proved. Xanthomatous change, with lipid in tumour cells, causes decrease in density on CT, but not to the levels of fat. As both lipomatous components and xanthomatous change show similar intensity on MRI, CT can be helpful in differentiating these two conditions. To our knowledge, our case is the only one in which the advent of fatty tissue was confirmed during follow-up.

Adipose Tissue↗