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Y Inoue

Publications and source records attributed to Y Inoue.

At least 829 records · Page 46Linked to original sources
PubMed1996

Identification of the structural gene for glyoxalase I from Saccharomyces cerevisiae.

The structural gene for glyoxalase I (GLO1) of Saccharomyces cerevisiae was identified. The GLO1 gene contained an open reading frame with 326 amino acids, and the molecular weight of the gene product (Glo1p) deduced from the DNA sequence was calculated to be 37,207.06. Glyoxalase I activity increased approximately 95-fold when the GLO1 gene was introduced into the yeast cell with a multicopy plasmid, and the resultant transformant showed the increased resistance against methylglyoxal. Since the knockout mutant of the GLO1 gene of haploid strain of S. cerevisiae was still viable, the GLO1 gene was thought to be unnecessary for growth of the yeast. The GLO1 gene was overexpressed in two kinds of glutathione-deficient mutants, gamma-glutamylcysteine synthetase-deficient (gsh1(-)) and glutathione synthetase-deficient (gsh2(-)), respectively, and the sensitivites to methylglyoxal were compared. The gsh1-deficient mutant, which could not produce glutathione at all, was hypersensitive to methylglyoxal, and overproduction of the Glo1p did not restore the growth arrest caused by exogenously added methylglyoxal. The gsh2-deficient mutant, which accumulates gamma-glutamylcysteine (an intermediate of glutathione biosynthesis), was also sensitive to methylglyoxal compared with the isogenic wild type strain, although the growth arrest caused by methylglyoxal was partially restored by overexpression of the GLO1 gene. Purified glyoxalase I from yeast could use gamma-glutamylcysteine as a substrate (kcat/Km = 1.89 x 10(7) M-1 s-1, glutathione; 3.47 x 10(4) M-1 s-1, gamma-glutamylcysteine).

Amino Acid Sequence↗
PubMed1996

Identification of 2-keto-3-deoxy-D-glycero--galactonononic acid (KDN, deaminoneuraminic acid) residues in mammalian tissues and human lung carcinoma cells. Chemical evidence of the occurrence of KDN glycoconjugates in mammals.

Since the discovery of KDN glycoprotein in 1986, the occurrence of KDN (= 2-keto-3-deoxy-D-glycero-D-galactonononic acid) glycan chains has been reported for different organisms ranging from bacteria to lower vertebrates, including amphibians and fish. Recently, the presence of alpha2-->8-linked oligo/polyKDN groups in mammalian tissues was shown by immunohistochemical and immunoblotting methods. In this communication we report the detection and quantitation of the KDN residues in glycoprotein and glycolipid fractions of rat tissues and human lung cancer cell lines by a highly sensitive fluorometric high-performance liquid chromatography (HPLC) method. We now provide unequivocal chemical proof of the occurrence of KDN in mammals by isolation of KDN from pig submaxillary gland and by structural assignment using chemical methods including fast atom bombardment-mass spectrometry, fluorescence-assisted HPLC analysis, gas-liquid chromatography, and 1H NMR spectroscopy.

Adenocarcinoma↗
PubMed1996

The prognostic significance of vascular invasion by endometrial carcinoma.

BACKGROUND: Recently, invasion of vascular spaces by endometrial carcinoma has received particular attention as a prognostic factor. The goal of the current investigation was to re-examine the effect of vascular invasion on tumor recurrence and survival in patients with endometrial carcinoma. METHODS: Surgical specimens from 238 patients with endometrial carcinoma were examined for the presence of vascular invasion by tumor cells. Vascular invasion was compared with clinicopathologic features and postoperative survival. Survival curves by vascular invasion were evaluated by the Kaplan-Meier method. RESULTS: In a histopathologic review of 238 cases of endometrial carcinoma, 82 neoplasms demonstrated vascular invasion. Vascular invasion significantly correlated with the extension of primary tumor, depth of myometrial invasion, and histologic grade. Patients with lymph node metastasis had a significantly higher incidence of vascular invasion. Survival at 5 years for patients with vascular invasion was 73.4%. This was significantly lower than the survival rate of 91.5% for women without this finding (P < 0.001). Among patients with lymph node metastasis, 80.2% of the patients with vascular invasion survived for 5 years compared with 95.3% of the patients without vascular invasion (P < 0.05). Ten of 47 patients with no lymph node metastasis but with vascular invasion developed recurrent carcinoma. Nine of these ten patients apparently had extrapelvic recurrences. CONCLUSIONS: The presence of vascular invasion is a reliable prognostic indicator. Recording of tumor recurrence pattern may lead to a better selection of patients for adjuvant systemic therapy after surgery.

Endometrial Neoplasms↗
PubMed1996

Cost-effectiveness of interferon-alpha and conventional chemotherapy in chronic myelogenous leukemia.

OBJECTIVE: To compare the cost-effectiveness of interferon-alpha with that of hydroxyurea as initial therapy for patients with chronic myelogenous leukemia (CML) in the chronic phase. DESIGN: A decision analysis and Markov model that described the natural history of the therapeutic process. The Markov model contained two treatment arms (interferon-alpha and hydroxyurea) and eight states of health (complete hematologic remission with cytogenetic response, complete hematologic remission without cytogenetic response, partial hematologic remission, chronic phase without hematologic remission, accelerated phase, blast crisis, bone marrow transplantation, and death). Probabilities, costs, and utilities were obtained from published clinical studies and clinical investigators. MEASUREMENT: Quality-adjusted years of life saved and costs and qualities discounted at 5% per year. SETTING: University medical centers in North America and Europe. PATIENTS: Meta-analysis of results from patients studied in clinical trials. RESULTS: The model's predictions of median survival (69 months with interferon-alpha therapy and 58 months with hydroxyurea therapy) were derived from data in the recent literature. In patients 50 years of age, interferon-alpha improved life expectancy over hydroxyurea by approximately 18 months. The marginal cost-effectiveness of interferon-alpha (incremental discounted cost of interferon-alpha compared with that of conventional therapy) was $34800 per quality-adjusted year of life saved. The model was sensitive to the monthly cost of interferon-alpha therapy (if the cost of interferon-alpha is reduced by one third, the cost-effectiveness becomes $19300 per quality-adjusted year of life saved) but was not particularly sensitive to the costs associated with blast crisis or bone marrow transplantation. The other significant variable was quality of life during therapy with interferon-alpha; when this measure was varied from 70% to 100% of the quality of life during hydroxyurea therapy, cost-effectiveness changed from $123200 to $25620 per quality-adjusted year of life saved. When the quality of life associated with interferon-alpha was less than 62% of the quality of life associated with hydroxyurea, the discounted quality-adjusted life expectancy with interferon-alpha was less than that with hydroxyurea. CONCLUSION: Compared with hydroxyurea, interferon-alpha is, in most clinical scenarios, a cost-effective initial therapy for patients with chronic-phase CML who can tolerate the drug.

Antineoplastic Agents↗
PubMed1996

Overexpression of either liver type or pancreatic beta cell type glucokinase via recombinant adenovirus enhances glucose oxidation in isolated rat hepatocytes.

To elucidate a role of glucokinase in hepatic glucose metabolism, we overexpressed hexokinase I (HKI), liver type glucokinase (LGK), or beta cell type glucokinase (beta GK) in primary rat hepatocytes using a recombinant adenovirus vector system. Overexpression of HKI and LGK induced a 34- and 25-fold increase, respectively, in glucose phosphorylation activity measured in cell homogenates. While HKI overexpression induced only a 1.3-fold increase in glucose oxidation, LGK overexpression increased glucose oxidation by 2.9-fold. Overexpression of beta GK had essentially the same effect as LGK. The results indicate that glucokinase does indeed regulate the rate of hepatic glucose oxidation and that the liver-specific sequence of this enzyme is not essential for this function.

Adenoviruses, Human↗
PubMed1996

EAAT4 is a post-synaptic glutamate transporter at Purkinje cell synapses.

To study cellular and subcellular localizations of the glutamate transporter EAAT4, antibody was raised against the N-terminal peptide. On immunoblotting the antibody recognized a band in membrane extracts from the cerebellum, but not from the forebrain. Immunohistochemistry revealed that its distribution was restricted to the cerebellar molecular layer, where the immunoreactivity was observed as numerous punctate stainings. Electron microscopy showed the antibody to label dendritic spines of the Purkinje cells. EAAT4 is, therefore, a Purkinje cell-specific, postsynaptic transporter. Together with dense localization of other transporter subtypes in Bergmann astrocytic membranes, Purkinje cell synapses are thus provided with distinct glutamate transporter subtypes at discrete synaptic elements, which would play important roles in regulating excitability of the Purkinje cells and protecting against excitotoxicity.

ATP-Binding Cassette Transporters↗
PubMed1996

Occupation of the QB-binding pocket by a photosystem II inhibitor triggers dark cleavage of the D1 protein subjected to brief preillumination.

The D1 protein of the photosystem (PS) II reaction center turns over very rapidly in a light-dependent manner initiated by its selective and specific cleavage. The cleavage of D1 was studied by using a PS II inhibitor, N-octyl-3-nitro-2,4,6-trihydroxybenzamide (PNO8), as a molecular probe. The following results were obtained. (i) D1 was selectively cleaved into 23-kDa N-terminal and 9-kDa C-terminal fragments in complete darkness by PNO8 at a single site in a D-E loop connecting membrane-spanning helices D and E. (ii) The cleavage was markedly enhanced when PS II was illuminated for a brief period before the addition of PNO8 in darkness. (iii) The effect of preillumination was slowly lost during incubation in the dark, with a decay half-time of approximately 1 h at 25 degrees C. (iv) The light intensity of preillumination required for the cleavage was much lower than that required for O2 evolution. (v) The light-triggered cleavage of D1 was observed in thylakoids, PS II membranes, and PS II core particles, but not in purified PS II reaction centers. More than 60% of D1 was cleaved into the two fragments with no other by-products. (vi) The cleavage reaction revealed a marked pH dependence that was considerably different from that for inhibition of PS II activity. The results are interpreted as indicating that the binding of PNO8 to the QB-binding pocket triggers proteolytic cleavage of D1 that has been previously modified during illumination.

Benzamides↗
PubMed1996

Occurrence and structural analysis of highly sulfated multiantennary N-linked glycan chains derived from a fertilization-associated carbohydrate-rich glycoprotein in unfertilized eggs of Tribolodon hakonensis.

This study represents the first detailed investigation of the nature of highly sulfated (keratan-sulfate-like) complex-type asparagine-linked glycans having a tetraantennary core structure and shows the effectiveness of fast-atom-bombardment mass spectrometric (FAB-MS) methods incorporating derivatization and mild methanolysis for analyzing such complex types of sulfated glycans. The structure of the N-glycan chains was unambiguously established by a combination of compositional analysis, methylation analysis, mild methanolysis for desulfation, hydrazinolysis/nitrous acid deamination, enzymatic (endo-beta-galactosidase and peptide:N-glycosidase F) digestions, and instrumental analyses (1H-NMR spectroscopy and FAB-MS) which revealed the novel repeating sulfated carbohydrate sequences, +/- Gal beta 1-->4Gal beta 1[-->(HSO3-->6)GlcNAc beta 1-->3(+/- Gal beta 1-->4)Gal beta 1]n--> (see Structure I; p + q + r + s approximately 14). This sequence is unique in: (a) the skeletal structure is similar to that of keratan sulfate but is completely devoid of 6-O-sulfated Gal residues and (b) the presence of branched Gal residues in the sequence -->4GlcNAc beta 1-->3(Gal beta 1-->4)Gal beta 1-->. [formula: see text]

Animals↗
PubMed1996

Developmental changes in expression and distribution of the glutamate receptor channel delta 2 subunit according to the Purkinje cell maturation.

The glutamate receptor (GluR) channel delta 2 subunit is considered to be a functional molecule involved in motor coordination, Purkinje cell synapse formation and cerebellar long-term depression. We examined developmental changes in expression and distribution of the GluR delta 2 in the mouse cerebellum by in situ hybridization and immunohistochemistry. The GluR delta 2 mRNA was detected as early as embryonic day 15 (E15) in a cell mass consisting of Purkinje neuroblasts in the posterior cerebellum. During late embryonic and postnatal periods, the GluR delta 2 mRNA was expressed abundantly and specifically in Purkinje cells. By immunohistochemistry, immunoreactivity of the GluR delta 2 was found in both shafts and spines of Purkinje dendrites at early postnatal period. By P21, however, the intense immunoreactivity became restricted to the dendritic spines, especially along the postsynaptic membrane in contact with parallel fiber terminals. These findings suggested that the transcription of the GluR delta 2 subunit occurs in the Purkinje cells from fetal through adult stage, but the intracellular localization of the protein products undergoes an alteration from non-synaptic to synaptic site when active synaptogenesis takes place.

Animals↗
PubMed1996

Location of the non-heme iron center on the alpha subunit of photoreactive nitrile hydratase from Rhodococcus sp. N-771.

Nitrile hydratase (NHase) from Rhodococcus sp. N-771, which possesses a non-heme iron center binding nitric oxide (NO), is activated by light irradiation. To localize the iron center in the protein, we quantified Fe atoms and performed FTIR measurements of the isolated alpha and beta subunits. The native NHase and the isolated alpha subunit contained about 1.0 and 0.8 mol Fe per mol protein, respectively, whereas the beta subunit contained only a trace of Fe. An NO stretching band was observed at 1852 cm-1 in the FTIR spectrum of the alpha subunit, but not in that of the beta subunit. Upon light irradiation of the alpha subunit, the affinity of the Fe atom decreased and the NO band disappeared from the FTIR spectrum. These observations indicate that the non-heme iron center, which is responsible for the photoreaction, is present in the alpha subunit.

Amino Acid Sequence↗
PubMed1996

Occurrence of poly(alpha2,8-deaminoneuraminic acid) in mammalian tissues: widespread and developmentally regulated but highly selective expression on glycoproteins.

In tissues of higher organisms homopolymers of alpha2,8-linked N-acetylneuraminic acid can be found as a posttranslational modification on selected proteins. We report here the discovery of homopolymers of alpha2,8-linked deaminoneuraminic acid [poly(alpha2,8-KDN)] in various tissues derived from all three germ layers in vertebrates including mammals. The monoclonal antibody kdn8kdn in conjunction with a bacterial KDNase permitted the detection of poly(alpha2,8-KDN) by immunohistochemistry and immunoblotting. Further evidence for the existence of poly(alpha2,8-KDN) was obtained by gas/liquid chromatography. The poly(alpha2,8-KDN) glycan was detectable in all tissues studied with the exception of mucus-producing cells present in various organs, the extracellular matrix, and basement membranes. However, in certain organs such as muscle, kidney, lung, and brain its expression was developmentally regulated. Despite its widespread tissue distribution, the poly(alpha2,8-KDN) glycan was detected on a single 150-kDa glycoprotein except for a single >350-kDa glycoprotein in kidney, which makes it most distinctive among polysialic acids. The ubiquitous yet selective expression may be indicative of a general function of the poly(alpha2,8-KDN)-bearing glycoproteins.

Animals↗
PubMed1996

Two-dimensional crystallization and cryo-electron microscopy of photosystem II.

Two dimensional (2D) crystals of photosystem II (PSII) were obtained from n-heptyl-beta-D-thioglucoside-solubilized monomers of spinach PSII complex by conventional detergent dialysis. The 2D crystals were either large cylindrical vesicles (1 to 2 micrometer by 4 to 6 micrometer as flattened vesicles) or large monolayer sheets (ca. 1 micrometer X 1 micrometer), both suitable for cryo-electron microscopy. Images of unstained crystals embedded in ice were recorded using low-dose microscopy and analyzed by digital image processing. Both types of crystals had the same unit cell size and the same packing arrangement of PSII particles. The plane group was p22(1)2(1) and the unit cell was rectangular with dimensions of 16.7 nm X 15.3 nm containing four monomers (two face-up and two face-down). SDS-PAGE and immunoblot analyses of the 2D crystal indicated that the constituent subunits of particles in the 2D were CP47, D1, D2, cytochrome b-559 and psbI protein. A projection map of 20 A resolution revealed that each monomer has asymmetrical shape with a length of 8.1 nm and a maximal width of 7.5 nm consisting of four areas of density. Two high-density areas with similar sizes were located close to each other to form a roughly rectangular core of 4.0 nm X 6.5 nm. From its size similarity to the size of the L/M heterodimer of the bacterial reaction center, this high density core area was tentatively assigned to the D1/D2 heterodimer. The remaining large and small areas were also tentatively assigned to CP47 and cytochrome b-559 plus psbI protein respectively.

Crystallization↗
PubMed1996

Synthesis and hypolipidemic activities of novel 2-[4-[diethoxyphosphoryl)methyl]phenyl]quinazolines and 4(3H)-quinazolinones.

The novel compound NO-1886, 4-[(diethoxyphosphoryl)methyl]-N-(4-bromo-2-cyanophenyl)-ben zamide, is a hypolipidemic agent, which appears to increase lipoprotein lipase activity in rats. Various analogs of NO-1886 were synthesized to study the structure-activity relationship of this hypolipidemic drug. A novel series of quinazolines and 4(3H)-quinazolinones were prepared by cyclization of NO-1886 derivatives. Derivatives bearing a 4-[(diethoxyphosphoryl)-methyl]phenyl] group at the 2-position were found to lower triglyceride and total cholesterol levels. In accord with the decrease in log P*, quinazolines and 4(3H)-quinazolinones showed good absorption and hypolipidemic activity. When the quinazolinone ring system is substituted at positions 6 and 7 with methoxy groups, increased hypolipidemic activity was observed. The highest hypolipidemic activity was observed when the 3-position was substituted by a methyl or benzyl group.

Animals↗
PubMed1996

The occurrence of novel 9-O-sulfated N-glycolylneuraminic acid-capped alpha2-->5-Oglycolyl-linked oligo/polyNeu5Gc chains in sea urchin egg cell surface glycoprotein. Identification of a new chain termination signal for polysialyltransferase.

We report the isolation and structural characterization of an oligo/polysialic acid-containing glycopeptide fraction (designated ESP-Sia) prepared from the egg cell surface complex of the sea urchin, Hemicentrotus pulcherrimus, by exhaustive pronase treatment. The carbohydrate chains isolated from ESP-Sia were shown to consist of O-linked oligo/polysialic acid-containing glycan units and N-linked carbohydrate chains. The present studies have revealed that the O-linked oligo/polysialic acid-containing glycan chains derived from the ESP-Sia were similar to those present in egg jelly coat polysialylated glycoprotein in being composed of tandem repeats of N-glycolylneuraminic acid (Neu5Gc) glycosidically linked in a novel fashion through the glycolyl group, (-->5-OglycolylNeu5Gcalpha2-->)n. However, they differ from the egg jelly coat in two key respects. First, the average degree of polymerization of the oligo/polysialic acid chains of ESP-Sia is only 3; a value far lower than that found in the jelly coat glycoprotein (average degree of polymerization was about 20). Second, ESP-Sia is uniquely characterized by the presence of 9-O-sulfated N-glycolylneuraminic acid (Neu5Gc9HSO3) residues at the nonreducing termini of the (-->5-OglycolylNeu5Gcalpha 2-->)n chains. The terminal sialyl residues in the Neu5Gc9HSO3 alpha2-->(-->5-OglycolylNeu5Gcalpha2-->)n chains were totally resistant to exosialidases. The discovery of Neu5Gc9HSO3 as the nonreducing terminal residue of oligo/poly(-->5-OglycolylNeu5Gcalpha 2-->) group is especially noteworthy in that Neu5Gc9HSO3 appears to be of limited distribution among glycoconjugates. Following the earlier discovery of oligo/polysialic acid chains capped with KDN, i.e. KDN alpha2-->(-->8Neu5Gcalpha2-->)n, found in rainbow trout egg polysialoglycoproteins, it now appears that the sulfated Neu5Gc can serve a similar capping function.

Acetylation↗
PubMed1996

Studies on selectin blocker. 1. Structure-activity relationships of sialyl Lewis X analogs.

As part of our studies of selectin blockers, we prepared 1-deoxy-3'-O-sulfo LeX analogs (1-3), 1-deoxy-3'-O-phosphono LeX analogs (4), and 1-deoxy sLeX analogs (5-7), and examined their inhibitory activities against natural ligand (sLeX) binding to E-selectin, P-selectin, and L-selectin. The 1-deoxy sLeX 5 was up to 20 times more potent an inhibitor than the sLeX tetrasaccharide toward P- and L-selectin binding. This indicates that the modification of the 1 or 2 position of sLeX is useful in the design of a more potent selectin blocker.

E-Selectin↗
PubMed1996

Substrate specificity of rainbow trout testis CMP-3-deoxy-D-glycero-D-galacto-nonulosonic acid (CMP-Kdn) synthetase: kinetic studies of the reaction of natural and synthetic analogues of nonulosonic acid catalyzed by CMP-Kdn synthetase.

In this report we present kinetic data of the activation reaction of several synthetic 3-deoxy-D-glycero-D-galacto-nonulosonic acid (Kdn) and N-acetylneuraminic acid (Neu5Ac) analogues catalyzed by the rainbow trout testis CMP-Kdn synthetase. This enzyme showed broad substrate specificity in terms of substitutions at C4 or C5 position of Kdn and Neu5Ac. In contrast, calf brain CMP-N-acylneuraminic acid synthetase had narrow substrate specificity, being active only on various N-acyl analogues of Neu5Ac and only slightly active on Kdn derivatives. Usefulness of the trout testis enzyme for synthesis of various CMP-sialate analogues, which could be donor substrates for sialyltransferases, was demonstrated.

Animals↗
PubMed1996

Dynamic changes in expression of glutamate transporter mRNAs in developing brain.

Developmental changes in gene expression for three glutamate transporter subtypes in the mouse brain were analysed by in situ hybridization. During embryonic stages, GluT-1 and GLT-1 mRNAs were expressed at high levels in the ventricular zone, whereas EAAC1 mRNA was not detected in the zone. In the mantle zone, transcription levels of three transporter mRNAs were low during embryonic stages, and these levels, especially those of the GluT-1 and GLT-1 mRNAs, displayed remarkable increases postnatally to reach maximal levels at 14 days of age. These dynamic developmental regulations suggest that the glutamate transporter not only regulates the excitatory synaptic transmission at mature stages, but might also be intimately involved in the brain development.

ATP-Binding Cassette Transporters↗