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Biomedical subjects

Y Mitsui

Publications and source records attributed to Y Mitsui.

At least 253 records · Page 14Linked to original sources
PubMed1989

Crystallization of a complex between ribonuclease Ms and 3'-guanylic acid.

The crystals of a complex between ribonuclease Ms, the extracellular ribonuclease from Aspergillus saitoi, and 3'-guanylic acid were obtained from 2-methyl-2,4-pentanediol solution by vapor diffusion technique in the hanging drop mode. The crystals belong to orthorhombic space group P2(1)2(1)2(1) with dimensions a = 47.0 A, b = 62.8 A, c = 37.9 A. The crystals diffract strongly up to at least 2.0 A resolution.

Aspergillus↗
PubMed1989

Differential activities of two distinct endothelin family peptides on ileum and coronary artery.

A synthesized mouse vasoactive intestinal contractor peptide, which belongs to a novel member of the endothelin family, induced a prolonged contraction in mouse ileum as well as porcine coronary artery in vitro. Studies comparing the effects of vasoactive intestinal contractor and endothelin on different tissues revealed that the maximum ileum contraction of vasoactive intestinal contractor was much higher than that of endothelin in both guinea pig and mouse systems, but that the vasoconstriction activity of vasoactive intestinal contractor was weaker than that of endothelin in porcine artery. These results show that vasoactive intestinal contractor might be a novel gastrointestinal hormone.

Animals↗
PubMed1989

Crystallization of a new class of microbial ribonuclease from Rhizopus niveus.

Crystals of ribonuclease Rh, a new class of microbial ribonuclease from Rhizopus niveus, were obtained from polyethylene glycol 8000 solution by a vapour diffusion technique in the hanging drop mode. Two crystal forms, type I and type II, were obtained from the same droplet solution. Both forms belong to the space group P2(1)2(1)2(1), but their cell dimensions are markedly different: a = 68.3 A, b = 73.0 A, c = 50.0 A for type I and a = 67.5 A, b = 72.3 A, c = 44.2 A for type II. The type I crystals diffract beyond 2.0 A resolution and are suitable for X-ray structure analysis at high resolution.

Crystallization↗
PubMed1989

A decrease in hyaluronic acid synthesis by aging human fibroblasts leading to heparan sulfate enrichment and growth reduction.

Cultured normal human fibroblasts during in vitro aging exhibited increased proportions of heparan sulfate (HS; a glycosaminoglycan (GAG) species) in the cell-associated GAG pool, coincident with decreased cell growth activity. An analysis of GAG metabolism demonstrated that human fibroblasts during aging became relatively rich in HS due to an alteration in the profile of GAG synthesis. HS became relatively enriched and hyaluronic acid (HA) relatively depleted through a decrease in HA synthase activity. An experimental enrichment of human fibroblast cultures with exogenous HS brought about an arrest of the cells in the G0/G1 phase and a decrease in the rate of S phase entry, coincident with aged cell growth behaviour. These results suggest that the change in HA synthesis is responsible, at least to some extent, for the growth reduction during aging of normal human fibroblasts.

Cell Division↗
PubMed1989

The human preproendothelin-1 gene: possible regulation by endothelial phosphoinositide turnover signaling.

Preproendothelin-1 (ppET-1) mRNA has previously been demonstrated to be markedly induced in cultured endothelial cells (EC) by the addition to the medium of thrombin, an agent known to stimulate phosphoinositide turnover in EC. In this study, the mechanism of regulation of ppET-1 mRNA expression was investigated in cultured human umbilical vein EC by RNA blot analysis with cloned ppET-1 gene as a probe. The mRNA for ppET-1 was rapidly upregulated by O-tetradecanoylphorbol-13-acetate (TPA) (0.5 microM) and by ionomycin (5 microM) within 10 min of addition to the medium, but not by forskolin (50 microM). The rapid induction of ppET-1 mRNA by TPA or ionomycin occurred even in the presence of cycloheximide, indicating that the mRNA induction does not require de novo protein synthesis. The ppET-1 mRNA was an extremely unstable species of mRNA with an apparent half-life of about 15 min. However, the half-life of ppET-1 mRNA was not appreciably affected by TPA or ionomycin, suggesting that the mRNA induction by these agents is mostly due to an activation of the transcription of the mRNA. These observations indicate that the production of ET-1 in human EC can be controlled by a transcriptional gene regulation directly coupled to the intracellular signals from the phosphoinositide-turnover pathway, i.e., activation of protein kinase C and increase in intracellular Ca2+. These mechanisms are discussed in relation to information on the primary structure of cloned ppET-1 gene.

Blotting, Northern↗
PubMed1989

[Temporary restoration using light-cured resin].

In spite of various problems involved in chemically cured resin (self-curing resin), e.g., irritability, and heat and shrinkage at polymerization, it has traditionally been the material of choice in the production of temporary restorations. However, light-cured resin, which does not have the disadvantages of chemically cured resin, has recently been developed and applied to clinical treatment. The present study was conducted to examine the clinical application of light-cured resin to temporary crowns. Two types of light-cured resin and one type of chemically cured resin were examined for their mechanical properties. The properties involved in handling and setting, and the methods of producing crowns were also studied. The results were as follows: 1) In the tensile strength test, there was no significant difference between the two types of light-cured resin, i.e., Triad and Unifast LC. The tensile strength of Unifast, a chemically cured resin, was slightly greater than the others, the difference being significant. 2) The Vickers hardness test showed no significant differences between the three types of resin. 3) The mechanical properties of Triad were not influenced by differences in the curing unit (the unit for general oral use or exclusive use) used for polymerization. 4) The test of setting properties revealed that Unifast LC needed longer than Unifast from the 2nd through the 4th clinical stage. In particular, Unifast LC required about 2.5 times the duration needed by Unifast at the 2nd stage in the tray method. 5) The heat generation test showed that the exothermic temperature in Unifast was significantly higher than in the two types of light-cured resin. 6) Heat generation associated with light curing was noted during the use of a light-curing unit for oral use.

Dental Restoration, Temporary↗
PubMed1988

Purification of basic FGF receptors from rat brain.

Receptor molecules for basic fibroblast growth factor (bFGF) were isolated from rat brain by a novel and rapid procedure and characterized. Purification was performed by wheatgerm agglutinin (WGA) gel affinity chromatography in combination with bFGF gel affinity chromatography, utilizing a novel elution method involving heparin. The eluted proteins were active in binding bFGF and were separated as two bands with respective molecular masses of 140 kDa and 110 kDa on SDS-PAGE. More than half of this bFGF-binding activity was lost after 16 h at 4 degrees C. Thus, bFGF receptors were purified as labile glycoconjugates.

Animals↗
PubMed1988

A novel growth factor in rat spleen which promotes proliferation of hepatocytes in primary culture.

We have identified a factor from adult rat spleen which stimulates the proliferation of rat hepatocytes. The activity was found in the spleen soluble matrix fraction (1,300xg supernatant of inter-cellular fraction). No activity was found in the spleen cell homogenate, in the spleen insoluble matrix fraction or rat serum. After 4 days of incubation with the spleen factor, the cell number increased 4-fold higher than that at inoculation. The growth stimulation were observed in both fetal bovine serum supplemented medium and hormonally defined medium which contains insulin, epidermal growth factor, glucagon, growth hormone and prolactin. The level of activity in the spleen soluble matrix was not affected by partial hepatectomy or trypsinization. These data indicate that the spleen factor is different from previously characterized effectors of hepatocyte proliferation. The novel factor has been named spleen derived growth factor (SDGF).

Animals↗
PubMed1988

Cloning and sequence analysis of cDNA encoding the precursor of a human endothelium-derived vasoconstrictor peptide, endothelin: identity of human and porcine endothelin.

A cDNA encoding a human endothelium-derived vasoconstrictor peptide, endothelin, was isolated from a human placenta cDNA library. The nucleotide sequence of this cDNA clone showed that the primary structure of the human preproendothelin has 212 amino acid residues and is highly homologous to porcine preproendothelin, and that human endothelin is identical with porcine endothelin.

Amino Acid Sequence↗
PubMed1988

A novel potent vasoconstrictor peptide produced by vascular endothelial cells.

An endothelium-derived 21-residue vasoconstrictor peptide, endothelin, has been isolated, and shown to be one of the most potent vasoconstrictors known. Cloning and sequencing of preproendothelin complementary DNA shows that mature endothelin is generated through an unusual proteolytic processing, and regional homologies to a group of neurotoxins suggest that endothelin is an endogenous modulator of voltage-dependent ion channels. Expression of the endothelin gene is regulated by several vasoactive agents, indicating the existence of a novel cardiovascular control system.

Amino Acid Sequence↗
PubMed1988

Evaluation of long-term cultured endothelial cells as a model system for studying vascular ageing.

Long-term cultures of human umbilical endothelial cells were examined for changes in cell growth, cell density, cell volume, occurrence of multinucleated cells, prostacyclin production and negative charge of the cell surface during in vitro cellular ageing. The changes observed were consistent with the previously described changes in vascular endothelial cells during in vivo ageing. Therefore, we conclude that cumulative cell division is deeply involved in in vivo ageing of endothelial cells and that this in vitro system is suitable for investigating in vivo ageing of vascular endothelial cells.

Aging↗
PubMed1988

hst-1 transforming protein: expression in silkworm cells and characterization as a novel heparin-binding growth factor.

A protein encoded by an hst-1 transforming gene was expressed in silkworm-derived BmN cells and secreted into the culture medium using a recombinant baculovirus vector. The strong affinity for heparin of the secreted protein made it possible to purify the hst-1 protein to homogeneity in a two-step procedure. The purified hst-1 protein has a molecular weight of 18,000 and stimulates both DNA synthesis in NIH3T3 cells and human umbilical vein endothelial cell proliferation. In addition, morphological changes and anchorage-independent growth of NIH3T3 cells are induced by this product. These results show that the hst-1 transforming protein is a novel heparin-binding growth factor as predicted by nucleotide sequence analysis.

Animals↗
PubMed1987

Crystallization and preliminary X-ray studies of human recombinant interleukin-2.

Two different forms of crystals (potentially) suitable for x-ray structure analysis were obtained for recombinant human interleukin-2 (IL-2) using ammonium sulfate as a precipitant in the pH range of 6.3-7.3 (in the case of hexagonal bipyramidal crystals) and 4.5-5.5 (in the case of plate crystals). The hexagonal bipyramidal crystal belongs to a hexagonal space group P6(2)22 or P6(4)22 with a = b = 105.8 A and c = 122.2 A. The crystal diffracts up to 3.4 A resolution and contains 2 or 3 IL-2 molecules in an asymmetric unit. The plate crystal belongs to an orthorhombic space group P2(1)2(1)2 with a = 47.9 A, b = 79.6 A, and c = 31.9 A. The crystal diffracts up to 2.5 A resolution and contains only 1 IL-2 molecule in an asymmetric unit. These facts reconfirmed crystallographically the high homogeneity of the present preparation of human recombinant IL-2.

Cloning, Molecular↗