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T Nishihara

Publications and source records attributed to T Nishihara.

At least 19 recordsLinked to original sources
PubMed1992

Identification of non heparin-binding endothelial cell growth factor from rat myofibroblasts.

Myofibroblasts (Mfs) from rat fat tissues produced a potent endothelial cell growth factor (Mf-ECGF). The growth factor activity found in the conditioned media from primary cultures of Mfs, was labile to heat (80 degrees C for 10 min) and proteinase (trypsin), and did not bind to heparin in the presence of 0.2 M NaCl. Mf-ECGF was partially purified 4760-fold with a recovery of 25% from serum-free conditioned media by sequential carboxymethyl (CM) ion-exchange column chromatography and gel filtration. This Mf-ECGF activity was recovered from the 40 kD region of a non-reducing SDS-PAGE, and from the pH region between 6.5 and 7 of isoelectric focusing, with recoveries of 20% and 65%, respectively. These results indicated that a major portion of ECGF activity in the conditioned media was clearly distinct from other well-known endothelial cell growth factors including fibroblast growth factors (FGFs).

Adipose Tissue↗
PubMed1992

Characterization of bovine liver cytosolic 3 alpha-hydroxysteroid dehydrogenase and its aldo-keto reductase activity.

1. 3 alpha-Hydroxysteroid dehydrogenase was purified to homogeneity from bovine cytosolic fraction, which was monomeric and its molecular weight was estimated to be about 35 kDa. 2. The enzyme had ability to catalyze NADP(H)-dependent oxidoreduction of position 3 alpha-hydroxy and keto group of steroids and also could catalyze the reduction of some ketones and quinones. 3. In addition, benzenedihydrodiol was one of the substrates of dehydrogenase activity with NADP+. 4. Indomethacin, synthetic steroids and SH-reagents were potent inhibitors for this enzyme. 5. Inactivation of the enzyme by GSSG-treatment was restored to its original activity by the addition of DTT. 6. The presence of coenzyme, 0.33 mM NADP+, completely protected from the DTNB-inactivation. 7. Bovine liver cytosolic enzyme immunologically crossreacted with rat liver 3 alpha-hydroxysteroid dehydrogenase.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

Purification and characterization of glutathione S-transferase isozymes in dog lens.

1. Two isozymes of glutathione S-transferase (GST-dl1 and GST-dl2) were purified to homogeneity from dog lens. 2. The subunit size and the isoelectric point were determined to be 24,000 and > pI 9.5 for GST-dl1 and 22,000 and pI 8.1 for GST-dl2. 3. It was judged that GST-dl1 is a class alpha enzyme and GST-dl2 belongs to class pi on the basis of their immunological properties and N-terminal amino acid sequences. 4. The expression pattern of glutathione S-transferase isoenzymes in dog lens is different from that in pig, rat and bovine lenses.

Amino Acid Sequence↗
PubMed1992

Study on human erythrocyte thioltransferase: comparative characterization with bovine enzyme and its physiological role under oxidative stress.

Thioltransferase, an enzyme which catalyzes the thiol/disulfide exchange reaction in the presence of GSH, was purified to homogeneity on 15% SDS-PAGE from human (36,000-fold purification) and bovine (23,000-fold) erythrocyte hemolysates. These enzymes had similar properties in their monomeric structures (M(r) = 11,000) and broad specificities for substrates ranging from low-molecular disulfides (S-sulfocysteine, cystamine, and cystine) to protein disulfides (trypsin and insulin). They were highly sensitive to SH-reagents (monoiodoacetic acid and mercuric chloride), but were protected from inactivation by the presence of disulfides (GSSG, cystamine, and cystine). Phosphofructokinase and pyruvate kinase that had been inactivated by disulfides were reactivated effectively by the addition of thioltransferase with GSH. In addition, disulfides in membrane proteins of human erythrocytes that have been oxidatively damaged by diamide treatment were reduced to the SH-free form more effectively by incubation with thioltransferase.

Amino Acids↗
PubMed1992

A novel dihydrodiol dehydrogenase in bovine liver cytosol: purification and characterization of multiple forms of dihydrodiol dehydrogenase.

Three enzymes (DD1, DD2, and DD3) having dihydrodiol dehydrogenase activity were purified to homogeneity from bovine cytosol. DD1 and DD2 were identified as 3 alpha-hydroxysteroid dehydrogenase and high-Km aldehyde reductase, respectively, as judged from their molecular weights, substrate specificities and inhibitor sensitivities. DD3 was a unique enzyme which could specifically catalyze the dehydrogenation of trans-benzenedihydrodiol and trans-naphthalenedihydrodiol without any activity toward the other tested alcohols, aldehydes, ketones, and quinones. The Km value of DD3 (0.18 mM) for benzenedihydrodiol was lower than those of other dihydrodiol dehydrogenases so far reported. DD3 immunologically crossreacted with DD1, but showed no crossreactivity with DD2. Additionally, DD3 was inhibited in a competitive manner, with a low Ki value of 1 microM, by androsterone, which was a good substrate for DD1. It was assumed that DD3 is a novel enzyme which is specific to dihydrodiols, exhibiting similarity to DD1 in immunological and structural properties.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

Biochemical defects of outermost layer deficient mutants during sporulation of Bacillus megaterium.

To determine the regulation of morphogenesis of the outermost layer, the thick layer outside the inner coat, of the Bacillus megaterium spore, we isolated 15 outermost layer deficient mutants of B. megaterium using transposon Tn917. Three mutant strains lacked both synthesis of the 48-kDa outermost layer protein and induction of two initial enzymes for galactosamine-6-phosphate polymer synthesis, evidence that these biochemical events are regulated in the cascade system during morphogenesis of the outermost layer.

Bacillus megaterium↗
PubMed1992

Characterization of multiple forms of carbonyl reductase from chicken liver.

Three enzyme forms (CR1, CR2 and CR3) of carbonyl reductase were purified from chicken liver with using 4-benzoylpyridine as a substrate. CR1 was a dimeric enzyme composed of two identical 25-kD subunits. CR2 and CR3 were monomeric enzymes whose molecular weights were both 32 kD. CR1 exhibited 17 beta-hydroxysteroid dehydrogenase activity as well as carbonyl reductase activity in the presence of both NADP(H) and NAD(H). CR2 and CR3 had similar properties with regard to substrate specificity and inhibitor sensitivity. They could exhibit the activity only with NADPH and had no hydroxysteroid dehydrogenase activity. CR2 and CR3 cross-reacted with anti-chicken kidney carbonyl reductase antibody, though CR1 did not. The results suggest that CR1 is a hydroxysteroid dehydrogenase, and CR2 and CR3 are similar to each other and to the kidney enzymes.

17-Hydroxysteroid Dehydrogenases↗
PubMed1992

Evidence for an autocrine/paracrine role for interleukin-6 in bone resorption by giant cells from giant cell tumors of bone.

Interleukin-6 (IL-6) is a multifunctional cytokine whose role in osteoclastic bone resorption has not been clearly defined. Therefore, we have used giant cells, which express many features of osteoclasts, from giant cell tumors of bone as a model to examine the role that IL-6 may play in human osteoclastic bone resorption. We found that conditioned medium from 24-h cultures of highly purified giant cells (10(6)/ml) contained large amounts of IL-6 (37.9 +/- 8.8 ng/ml), similar to the amount of IL-6 produced by tumor stromal cells (29.8 +/- 11.5 ng/ml). Giant cells and stromal cells from giant cell tumors expressed IL-6 mRNA, as indicated by polymerase chain reaction analysis and in situ hybridization studies, and immunohistochemical techniques demonstrated that the giant cells expressed IL-6 receptors. The addition of a neutralizing antibody to IL-6 significantly decreased the area of dentine resorbed by purified giant cells in a dose-dependent manner, and the addition of IL-6 to cultures of purified giant cells pretreated with anti-IL-6 restored the resorbing capacity of the giant cells. These data suggest that IL-6 may act as both an autocrine and a paracrine factor for human osteoclasts and play an important role in the bone-resorbing capacity of these cells.

Base Sequence↗
PubMed1992

Glutathione S-transferase isozymes in rat lens.

Rat lens contains two classes of glutathione S-transferase (GST) isozymes; one is class mu, Yb1-Yb1, and the other is class pi, Yp-Yp, judged from their molecular weights, immunological properties and N-terminal amino acid sequences. The expression pattern of GST isozymes in the rat lens is different from that in pig and bovine lenses which have only class pi and class mu isozymes, respectively.

Amino Acid Sequence↗
PubMed1991

6-Deoxy-D-talan and 6-deoxy-L-talan. Novel serotype-specific polysaccharide antigens from Actinobacillus actinomycetemcomitans.

Serotype-specific polysaccharide antigens from Actinobacillus actinomycetemcomitans ATCC 29523 (serotype a) and NCTC 9710 (serotype c) were extracted from whole cells by autoclaving and purified by ion-exchange chromatography and gel filtration. Analysis of component sugars by gas-liquid chromatography-mass spectrometry, high performance liquid chromatography, and NMR together with optical rotation data showed that the serotype a antigen was composed solely of 6-deoxy-D-talose, whereas the serotype c antigen consisted of 6-deoxy-L-talose. Structural analysis indicated that both of these antigens were composed of closely related repeating units, -3)-6-deoxy-alpha-D-Talp-(1-2)-6-deoxy-alpha-D-Talp-(1-(sero type a) and -3)-6-deoxy-alpha-L-Talp-(1-2)-6-deoxy-alpha-L-Talp-(1-(sero type c). 1H and 13C NMR analysis showed that both of these serotype antigens contained one acetyl group/2 sugar residues. These acetyl groups localized at the O-2 position of 3-linked 6-deoxy-D-talose (serotype a) or O-4 position of 3-linked 6-deoxy-L-talose residues (serotype c), respectively. These results coupled with our previous findings on the serotype b antigen (Amano, K., Nishihara, T., Shibuya, N., Noguchi, T., and Koga, T. (1989) Infect. Immun. 57, 2942-2946) showed that the serotype antigens from A. actinomycetemcomitans are a group of novel polysaccharides with structural features closely related biosynthetically.

Actinobacillus↗
PubMed1991

Pig lens glutathione S-transferase belongs to class Pi enzyme.

Class Pi glutathione S-transferase was purified to homogeneity from pig lens cytosol. This enzyme was composed of two identical 22 kDa subunits and had isoelectric point of 8.5 from the results of SDS gel electrophoresis, gel filtration, amino acid sequence analysis and isoelectric focusing. Amino acid sequence of N-terminal 15 residues was almost identical to class Pi enzymes from human, rat and mouse. Antibody against the pig enzyme crossreacted to human glutathione S-transferase-pi and anti-rat glutathione S-transferase-P antibody crossreacted to pig enzyme.

Amino Acid Sequence↗
PubMed1991

Transcriptional regulatory elements in the 5' upstream and first intron regions of the human smooth muscle (aortic type) alpha-actin-encoding gene.

We have determined the nucleotide (nt) sequence of 5.5 kb including the 5' flanking, first untranslated exon and first intron regions of the human smooth muscle (SM) (aortic type) alpha-actin-(Sm alpha A)- encoding gene. The promoter region and a part of the first intron show remarkably high sequence conservation with equivalent regions of the chicken gene, and contain multiple transcriptional regulatory elements. From transient chloramphenicol acetyltransferase gene (cat) expression assays in SM cells, a DNA fragment from nt -123 to +49 containing two CArG boxes showed strong positive promoter activity, whereas a far upstream region from nt -253 to -124 showed a negative effect. The conserved region in the first intron also contains the CArG box and showed an enhancer activity. Therefore, the human SM alpha A gene is controlled under positive and negative mechanisms.

Actins↗
PubMed1991

Inactivation of human placenta glutathione S-transferase by SH/SS exchange reaction with biological disulfides.

The oxidized glutathione inhibited the activity of glutathione S-transferase purified from human placenta just through competitive inhibition. On the other hand, cystine and cystamine inactivated the activity by pseudo first-order in low concentrations, accompanying the stoichiometric incorporation of the radioactivity of [14C]-cystine to the enzyme protein until a half mole per one subunit. This and the protective effect of glutathione analogues suggested that the SH/SS exchange reaction occurred between the disulfide and the SH group near the glutathione binding site of the enzyme to form a mixed disulfide.

Cystine↗
PubMed1991

Structure and function of the extracellular matrix of anuran eggs.

The extracellular matrix (ECM) surrounding the anuran egg is composed of jelly coat layers, an envelope, and the perivitelline space, which separates the envelope from the egg plasma membrane. Both the jelly coat layers and egg envelopes are required for fertilization in anurans. This paper reviews the current understanding of the structure-function relations of the ECM, with emphasis on the egg envelope. The fibrous egg envelope exists in four related forms. The envelope forms differ in their ultrastructures, macromolecular compositions, and cellular functions. After the oocyte is released from the ovary, conversion of one envelope form to another is brought about by factors secreted by the oviduct prior to fertilization and by factors released from the egg in the sperm-triggered cortical reaction. An additional extracellular matrix structure, located in the perivitelline space, has recently been identified in Xenopus laevis, as well as a previously undescribed reorganization of envelope fibers occurring at fertilization. The molecular changes in the ECM glycoproteins (limited proteolysis, lectin-ligand binding, and conformational changes) and the oviductal and egg macromolecules responsible for the conversion of envelope forms are discussed. New experimental evidence that supports the lectin-ligand hypothesis for the formation of the fertilization layer is presented. It is proposed that the molecular changes in the ECM are responsible for the ultrastructural alterations of the ECM and for modifications of the fertilization and developmental functions of the anuran egg ECM.

Animals↗
PubMed1991

Role of interleukin-1 and prostaglandin in in vitro bone resorption induced by Actinobacillus actinomycetemcomitans lipopolysaccharide.

Lipopolysaccharide (Y4 LPS) isolated from Actinobacillus actinomycetemcomitans strain Y4 induced bone resorption in BALB/c mouse calvaria organ culture. The calcium release from LPS-low responsive C3H/HeJ mouse calvaria by Y4 LPS was very low. Indomethacin almost completely inhibited prostaglandin E2 (PGE2) production by Y4 LPS-stimulated BALB/c mouse calvaria, but did not suppress interleukin-1 (IL-1) release from the calvaria, and partially suppressed the bone resorption. Dexamethasone strongly inhibited the PGE2 and IL-1 production by Y4 LPS-stimulated BALB/c mouse calvaria, as well as Y4 LPS-induced bone resorption. Dexamethasone inhibited expression of membrane IL-1 on osteoblastic cells stimulated with Y4 LPS, but indomethacin did not. Furthermore, anti-IL-1 serum partially suppressed the calcium release from Y4 LPS-stimulated BALB/c mouse calvaria. These results suggest that both PGE2 and IL-1 participate in Y4 LPS-induced bone resorption in vitro.

Actinobacillus↗
PubMed1991

Murine macrophage interleukin-1 release by capsularlike serotype-specific polysaccharide antigens of Actinobacillus actinomycetemcomitans.

Serotype-specific polysaccharide antigens (SPAs) were extracted from whole cells of Actinobacillus actinomycetemcomitans ATCC 29523 (serotype a), Y4 (serotype b), and NCTC 9710 (serotype c) by autoclaving and purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300 columns. Y4 SPA induced interleukin-1 (IL-1) release by P388D1 murine macrophages. Polymyxin B had virtually no effect on the release of IL-1. Rabbit anti-murine IL-1 serum strongly suppressed the proliferation of C3H/HeJ mouse thymocytes induced with the culture supernatants of Y4 SPA-stimulated P388D1 cells and a submitogenic dose of concanavalin A. Gel filtration of the culture supernatants of Y4 SPA-stimulated macrophages on Sephacryl S-200 showed that an IL-1 peak at a point corresponding to approximately 16.5 kDa was eluted. The ability of SPAs from strains ATCC 29523 and NCTC 9710 to induce the release of IL-1 was lower than that of Y4 SPA. The IL-1-releasing ability of serotype a and c antigens was enhanced by deacetylation of both polysaccharides, suggesting that acetyl groups of these antigens might hinder the interaction between the antigens and macrophages.

Actinobacillus↗