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Biomedical subjects

N Taniguchi

Publications and source records attributed to N Taniguchi.

At least 577 records · Page 32Linked to original sources
PubMed1985

Purification and properties of rat liver globotriaosylceramide synthase, UDP-galactose:lactosylceramide alpha 1-4-galactosyltransferase.

The enzyme which catalyzes the transfer of galactose from UDP-galactose to lactosylceramide (LacCer) was obtained in a 32,000-fold purified and apparently homogeneous form from rat liver by a procedure involving affinity chromatography on UDP-hexanolamine-Sepharose and LacCer-Sepharose. The enzyme is composed of two nonidentical subunits whose apparent molecular weights are 65,000 and 22,000. Methylation and hydrolysis of the product formed by incubation of the enzyme with UDP-galactose and [3H]LacCer yielded 2,3,6-tri-O-methyl-[3H]galactose, indicating that a galactose residue was introduced to position C-4 of the terminal galactose of the LacCer. The product also specifically reacted with monoclonal antibody directed to globotriaosylceramide (Gal alpha 1-4Gal beta 1-4Glc beta 1-1Cer). This indicates that the purified enzyme is exclusively alpha 1-4-galactosyltransferase. Studies on substrate specificity indicate that the purified enzyme is highly specific for the synthesis of GbOse3Cer and is clearly distinct from the enzymes responsible for the formation of iGbOse3Cer (Gal alpha 1-3Gal beta 1-4Glc-Cer) and blood group-B substance, which possess alpha 1-3 galactosidic linkages at the nonreducing termini. The enzyme is also distinct from the alpha 1-4-galactosyltransferase which catalyzes the formation of galabiaosylceramide (Gal alpha 1-4Gal beta 1-1Cer) and IV4Gal-nLacOse4 (P1 antigen). These studies represent the first report of the properties of a highly purified alpha-galactosyltransferase catalyzing the transfer of sugar residues to glycolipids.

Animals↗
PubMed1985

Protein phosphorylation of beta-glucuronidase in human lung cancer--identification of serine- and threonine-phosphates.

Slices of human lung cancer tissue were incubated with [32P]-orthophosphoric acid, and the radiolabeled beta-glucuronidase was isolated by a procedure including immunoaffinity chromatography on anti-human liver beta-glucuronidase IgG Sepharose. Following removal of endo-beta-N-acetyl-glucosaminidase H-releasable carbohydrate portions of the enzyme, the protein moiety was acid-hydrolyzed. Two-dimensional separation of the hydrolysate identified phosphoserine and phosphothreonine. This is the first demonstration of protein phosphorylation in lysosomal beta-glucuronidase.

Adenocarcinoma↗
PubMed1985

A study of zinc distribution in erythrocytes of normal humans.

The assignment of zinc bound to carbonic anhydrase isoenzymes (CA-I and CA-II) and Cu2 Zn2 superoxide dismutase (SOD1) was investigated in the hemolysates from 21 normal male subjects. Sufficient care was taken to remove leukocytes and platelets. The following values of zinc distribution were obtained: total zinc, 113.8 +/- 22.7 (mean +/- S.E.) micrograms X 100 ml-1; CA-I-derived zinc, 866.6 +/- 26.2 micrograms X 100 ml-1; CA-II-derived zinc, 99.9 +/- 3.9 micrograms X 100 m-1; SOD1-derived zinc, 60.3 +/- 1.9 micrograms X 100 ml-1; the other zinc, 87.0 +/- 12.6 micrograms X 100 ml-1. Namely, 7.6% of the zinc in human erythrocytes is not bound to the carbonic anhydrases and Cu2Zn2 superoxide dismutase, but present in available form or attached to other enzymes.

Adult↗
PubMed1985

Some evidence for the in vivo functional activation of suppressor T cells in asymptomatic patients with hemophilia A receiving Factor VIII concentrates.

Of 14 asymptomatic hemophilia A patients receiving factor VIII concentrates, 11 severe hemophilia patients had an inverted T-helper/suppressor ratio but 3 moderate patients had a normal ratio. Most hemophilia patients showed poor lymphocyte proliferative responses to mitogens and diminished in vitro immunoglobulin-producing ability of lymphocytes. One important finding was that most patients were found to have increased numbers of Ia-like antigen-positive suppressor T cells, suggesting that circulation activated suppressor T cells. In addition, OKT8+ suppressor T cells from severe hemophilia patients showed strong suppressor activity on B-cell differentiation in a Nocardia delipidated cell mitogen-driven system, whereas those from normal age-matched controls showed no suppressor function. These results suggested that suppressor T cells in hemophilia patients treated with factors might be already activated in vivo by undetermined mechanisms, implying the presence of a peculiar immunoregulatory status in this disease.

Adolescent↗
PubMed1985

Impaired natural killer cell activity in Bloom's syndrome could be restored by human recombinant IL-2 in vitro.

Natural killer (NK) activity against K562 tumor cells was evaluated in peripheral blood nonadherent mononuclear cells (PBMNC) obtained from four patients with Bloom's syndrome. NK activity of PBMNC from all patients was found to be depressed to less than half of age-matched control values. However, all patients showed the normal percentages of large granular lymphocytes and of cells expressing the NK-cell-associated determinants (OKM1, Leu-7, and Leu-11). Although recombinant interferon-beta or -gamma augmented NK activity of patients' PBMNC in a manner similar to their effects on NK activity of normal individuals, impaired NK activity of PBMNC from Bloom's patients could be restored to normal ranges only by recombinant interleukin 2 (IL-2). These results suggested that IL-2 and interferons might participate in boosting NK activity of Bloom's syndrome in different ways.

Adolescent↗
PubMed1985

The p-nitrophenyl phosphatase activity of ubiquitin from bovine erythrocytes.

Ubiquitin, a unique protein with esterase and carbonic anhydrase activity, has been found to have also a p-nitrophenyl phosphatase activity. This phosphomonoesterase activity of ubiquitin has an acidic pH optimum; its true substrate appears to be the phosphomonoanion, with a Km of 1.8 X 10(-3) M. It is competitively inhibited by the typical acid phosphatase inhibitors, arsenate (Ki = 1.3 X 10(-3) M), molybdate (Ki = 1.2 X 10(-6) M), and phosphate (Ki = 1.4 X 10(-3) M). These inhibitors have no effect on the CO2 hydration and p-nitrophenyl acetate esterase activities of the ubiquitin. Acetazolamide slightly inhibited the p-nitrophenyl phosphatase activity.

4-Nitrophenylphosphatase↗
PubMed1985

A monoclonal antibody against gamma-glutamyltransferase from human primary hepatoma: its use in enzyme-linked immunosorbent assay of sera of cancer patients.

A monoclonal antibody, gamma-120, was raised against a highly purified gamma-glutamyltransferase (gamma GT) from human primary hepatoma. The antibody preferentially bound to the small subunit of gamma GT from human hepatoma and kidney as evidenced by immunoblot analysis. Weak binding to the normal liver enzyme could be detected by solid-phase enzyme-linked immunosorbent assay (ELISA). With the use of this antibody, an ELISA was developed for the quantitation of immunoreactive gamma GT in human serum. Sera of 188 normal control subjects displayed a low level (9.4 micrograms/ml) of immunoreactive gamma GT. Highly elevated levels of immunoreactive gamma GT were detected in the sera of patients with primary hepatoma, metastatic liver cancer, pancreatic cancer, and certain types of lung cancer. Slightly elevated levels of immunoreactive gamma GT were seen in the sera of patients with liver cirrhosis. The levels of gamma GT were within a normal range in the sera of patients with gastrointestinal cancers and patients with nonmalignant diseases such as hepatitis and gallstones. The antibody has been shown to be useful for the diagnosis of some of the neoplastic diseases.

Antibodies, Monoclonal↗
PubMed1985

Purification and properties of galactosylceramide sulfatase activator from human liver.

Activator protein for galactosylceramide sulfatase (GSase) was purified from human liver. The activator has an approximate molecular weight of 22,000, is glycoprotein in nature, and is most probably a trimer consisting of an 8,000 dalton monomer. Monospecific rabbit antiserum raised against the activator strongly inhibited the activity of the activator. In the presence of a 10-fold or more excess of galactosylceramide sulfate (GS) on a molar basis, GS binding to the GSase activator occurred, and was saturated at an equimolar ratio. Binding studies on the GSase activator were conducted using affinity chromatography on derivatives of GS as ligands, and gel filtration of mixtures containing glycolipids and the activator. A "GS-acid" derivative, which was prepared by oxidative cleavage of sphingosine moiety in GS, and a sulfonamide derivative of GS as ligands still retained affinity for the GSase activator, while a hydrophobic ligands, an aminohexyl group did not bind completely the activator. A ligand of "galactosylceramide-acid" had weak affinity for GSase activator. These results suggest that the sulfate group and one of the two hydrocarbon chains in GS are not essential for the binding of the activator. The affinity of galactosylceramide for the GSase activator was confirmed by the detection of the lipid-protein complex on gel filtration. The activator weakly stimulated porcine GM1-beta-galactosidase activity.

Antigen-Antibody Complex↗
PubMed1985

Increased generation of leukotriene C4 from eosinophils in asthmatic patients.

Human eosinophils with a density of over 1.095 were isolated from peripheral blood by dextran sedimentation, centrifugation with Lymphoprep and density gradients with Percoll. After the cells (1 X 10(5)/ml) were incubated with 1 microgram/ml calcium ionophore A23187 for 20 min, leukotriene C4 (LTC4) content in the supernatant was measured by radioimmunoassay. The generation of LTC4 was significantly higher in the cells from extrinsic asthmatics (23.5 +/- 14.8 ng/10(6) cells, mean +/- SD, n = 26, P less than 0.01) and intrinsic asthmatics (24.6 +/- 20.6 ng/10(6) cells, n = 27, P less than 0.01 as compared with normal healthy subjects (8.3 +/- 7.7 ng/10(6) cells, n = 10). There was no significant difference in the generation of LTC4 between intrinsic and extrinsic asthmatics. These observations indicate that eosinophils from asthmatic patients have increased ability to release LTC4.

Adult↗
PubMed1985

Exercise-induced changes in blood zinc and related proteins in humans.

Effects of cycle ergometer exercise (approximately 75% maximum ventilatory O2 consumption for 30 min) on the concentrations of zinc and related proteins in erythrocytes and/or plasma were studied on 11 sedentary male students. Lower concentrations of total zinc and of zinc derived from carbonic anhydrase I type (CA-I) in erythrocytes were observed immediately after exercise, but they disappeared after 30 min of rest. The change in total zinc concentration in erythrocytes correlated well with that in CA-I concentration immediately after exercise, as well as after rest. The concentration of carbonic anhydrase II type (CA-II)-derived zinc did not vary substantially at any time. On the other hand, there were significant increases in the plasma concentrations of total zinc and of alpha 2-macroglobulin (alpha 2-MG)-bound zinc immediately after exercise, whereas no such effect was noted in albumin-bound zinc. A positive correlation was found between total zinc and alpha 2-MG concentrations in plasma immediately after exercise. In addition, the change in the activity of alkaline phosphatase, a zinc metalloenzyme, correlated well with that in the total zinc concentration in plasma. These results suggest that a brief physical exercise induces the movement of zinc into plasma.

Adult↗
PubMed1985

Release of leukotriene C4 from human eosinophils and its relation to the cell density.

Human eosinophils and neutrophils were isolated from 20 ml of peripheral blood by dextran sedimentation, centrifugation with lymphoprep, and density gradient centrifugation with Percoll. The incubation of neutrophils of purity higher than 99% (density: 1.080-1.085 g/ml) with calcium ionophore A23187 for 20 min resulted in the release of a little amount of leukotriene C4 (2.3 +/- 0.6 ng/10(6) cells) as measured with a commercial radioimmunoassay kit. On the other hand, the release from eosinophils was over 10 times that from neutrophils. When the releasability of leukotriene C4 from eosinophils was examined in relation to the cell density, the eosinophils with lower density were observed to produce greater amounts of leukotriene C4.

Biological Assay↗
PubMed1985

Distribution of zinc and copper in maternal and cord blood at delivery.

For 17 normal births, the concentrations of trace metals (zinc and copper) and related metalloenzymes, i.e., carbonic anhydrase isoenzymes (CA-I and CA-II) and Cu2Zn2 superoxide dismutase (SOD1) were simultaneously determined in maternal and cord blood at delivery. Eleven healthy nonpregnant women served as controls. CA-I concentration in maternal erythrocytes was higher than in controls (p less than 0.05), whereas the concentrations of both CA isoenzymes in cord erythrocytes were in the range of one seventh to one ninth of those in controls. On the other hand, the erythrocyte SOD1 concentration was constant. A very low total zinc concentration was noted in cord erythrocytes, and this was due to the low concentrations of both CA isoenzymes. Total copper concentration in maternal erythrocytes was significantly lower than in controls (p less than 0.05); in contrast, that in cord erythrocytes was significantly higher than in controls (p less than 0.05). Thus, variations in erythrocyte copper concentrations are due to changes in other forms of copper (not SOD1-derived). Copper concentration in maternal plasma was about three times higher than in controls, while copper concentration in cord plasma was less half of that in control plasma. Conversely, zinc concentration in cord plasma was significantly higher than in controls (p less than 0.05). The concentrations of these metals in maternal erythrocytes and plasma were significantly different from the respective concentrations in cord erythrocytes and plasma. Likewise, the concentrations of these metals in maternal and cord erythrocytes contrasted with the corresponding concentrations in their plasma.

Carbonic Anhydrases↗
PubMed1985

Measurement of human serum immunoreactive gamma-glutamyl transpeptidase in patients with malignant tumors using enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay for human immunoreactive gamma-glutamyl transpeptidase (gamma-GTP) was developed. This assay was found to be simple, reproducible, and sensitive to 10 ng of the enzyme. Serum immunoreactive gamma-GTP content was significantly elevated in patients with various malignant tumors including liver cell cancer, lung cancer, gastric cancer, esophageal cancer, and colorectal cancer. On the other hand, in sera of patients with nonneoplastic diseases, the immunoreactive gamma-GTP content was not significantly elevated. No correlation was found between the serum levels of gamma-GTP determined by enzymatic assay and enzyme-linked immunosorbent assay, which indicates that, due to the presence of endogenous inhibitors and/or activators in sera, the enzyme activity may not reflect the true amount of enzyme protein. The measurement of immunoreactive gamma-GTP protein in sera appears to be useful for the detection and monitoring of certain malignant tumors.

Cross Reactions↗
PubMed1985

Globoside and Forssman synthases in human lymphocytes exposed to Epstein-Barr virus and mitogens.

The activities of two glycolipid synthetases, globoside synthase or UDP-N-acetylgalactosamine-trihexosylceramide beta-N-acetylgalactosaminyltransferase (beta-GalNAc transferase; EC 2.4.1.79) and Forssman synthase or UDP-N-acetylgalactosamine-globoside-alpha-N-acetylgalactosaminyltransfer ase (alpha-GalNAc transferase; EC 2.4.1.88), were assayed in various human lymphoblastic cell lines. The activity of beta-GalNAc transferase was much higher than that of alpha-GalNAc transferase except in Molt 3 and Molt 4 lines, which were derived from T-cells. In cultivated human peripheral lymphocytes concanavalin A (Con A), lipopolysaccharide (LPS), and Epstein-Barr virus (EBV) stimulated the activities of alpha- and beta-GalNAc transferases in addition to having their known stimulative effect on thymidine incorporation. Characteristic differences between alpha- and beta-GalNAc transferases were noted in the responses to the above mitogens, but activities of both enzymes were greatly increased by exposure of the lymphocytes to EBV. Treatment of lymphocytes with either dactinomycin (actinomycin D) or cycloheximide 24 hours after the addition of Con A, LPS, or EBV decreased the activities of the transferases. This observation suggests that stimulation of alpha- and beta-GalNAc transferases requires transcriptional and translational processes.

Cell Line↗
PubMed1985

Phosphotyrosine phosphatase activity in human placenta.

A phosphotyrosine phosphatase was enriched 9-fold from human placenta homogenates using ammonium sulfate fractionation and chromatographies on P-cellulose and Phenyl Sepharose. The enzyme preparation hydrolyzed phosphotyrosine, p-nitrophenyl phosphate, as well as phosphoenol-pyruvate. The enzyme was unstable, and its Km value for phosphotyrosine increased during the purification procedure. The optimum pH for phosphotyrosine was found to be pH 7.0. The phosphotyrosine phosphatase activity was completely inhibited at 2.6 mM Cu2+. Zn2+ was slightly inhibitory to the phosphatase activity. The effects of several inhibitors on the phosphotyrosine phosphatase activity were different from those on the p-nitrophenyl phosphatase activity. These results suggest that the phosphotyrosine phosphatase activity from human placenta is different from previously reported acid and alkaline phosphatases.

Cations, Divalent↗