Search PubMed⌕ Search

Biomedical subjects

T Koike

Publications and source records attributed to T Koike.

At least 721 records · Page 40Linked to original sources
PubMed1985

Specificity of mouse hybridoma antibodies to DNA. III. Antigenic determinants of nucleic acids recognized by poly(dG) specific monoclonal antibodies.

Immunochemical properties of monoclonal autoantibodies to single stranded DNA (ssDNA), which were derived from systemic lupus erythematosus (SLE) prone mice and were specific for poly(dG), were studied using a hapten inhibition assay with oligo- and mononucleotides. Deoxyguanosine monophosphate (dGMP) completely inhibited the ssDNA binding of poly(dG) specific monoclonal antibodies. The affinity to deoxyguanosine was approximately 70% of dGMP, and to guanosine monophosphate (GMP) and to guanosine was 38% and 24%, respectively. In contrast, other purine monomers such as deoxyadenosine monophosphate (dAMP), adenosine monophosphate (AMP) and adenosine exhibited virtually no inhibitory effect on the ssDNA binding of these monoclonal hybridoma autoantibodies. By the same competitive inhibition enzyme immunoassay using deoxyguanosine oligonucleotides of various chain lengths, the minimal antigenic size of ssDNA encompassed by the combining site of the Fab portion of anti-ssDNA monoclonal autoantibodies was determined to be the tetra- or pentanucleotide.

Animals↗
PubMed1985

Anti-IgE autoantibody in patients with atopic dermatitis.

The anti-IgE autoantibody in the IgG class was detected in 39/45 (86.7%) patients with atopic dermatitis by using a newly established solid-phase enzyme immunoassay. The epsilon-chain specificity of the anti-IgE autoantibody was confirmed by competitive inhibition by using human IgG, IgA, IgM, IgD, IgE, and heat-denatured IgE protein. Significant correlations were observed between the levels of the anti-IgE autoantibody and the serum IgE. Gel filtration studies indicated that the anti-IgE autoantibody in sera from atopic dermatitis was mainly present in the form of an immune complex with self IgE. The role of the IgE-anti-IgE immune complex and the role of the anti-IgE autoantibody in the modulation of the IgE-mediated immune system in atopic dermatitis are discussed.

Antibodies, Anti-Idiotypic↗
PubMed1984

Temperature and pH dependence of nerve growth factor-mediated neurite outgrowth of PC12 pheochromocytoma cells.

Nerve growth factor-mediated neurite outgrowth of PC12 pheochromocytoma cells was dependent on medium pH and temperature. Optimal pH was 6.8-7.1. No neurites were formed below 25 degrees C, and the number of cells having neurites increased upon elevating temperature. In contrast, the cells pretreated with nerve growth factor in suspension culture developed neurites even at 25 degrees C when they were transferred to monolayer culture. Temperature dependence of rates of the neurite formation indicates that apparent activation energy for this process is 44.6 kJ/mol.

Adrenal Gland Neoplasms↗
PubMed1984

Nucleosidediphosphate kinase from Ehrlich ascites tumor cells.

A phosphate-incorporating protein has been highly purified from the cytosol of Ehrlich ascites tumor cells (EAT cells). The nitrocellulose membrane method was used to follow the progress of the purification by quantitation of the [32P]phosphorylated form of the protein. The purified protein was identified as an NDP-kinase since it exhibited NDP-kinase activity and had enzyme characteristics in common with other NDP-kinases from various mammalian cells. The purified NDP-kinase was found to have a molecular weight of approximately 76,000 daltons. Moreover, the enzyme appears to consist of two distinct polypeptides (18,000 and 20,000 daltons). This enzyme contained 19 amino acids, with high levels of glycine (9.8%) and lysine (9.0%). The enzyme rapidly formed a [32P]phosphoenzyme when incubated with [gamma-32P]ATP in the presence of Mg2+ (1 mM) at the optimum pH of 7.5 even at low temperature (below 4 degrees C). This phosphoenzyme is an enzyme-bound, high-energy-phosphate intermediate, because ATP was formed from it on incubation with ADP in the presence of Mg2+ (1 mM). This finding suggests that the phosphoenzyme functions as an intermediate in NDP-kinase action.

Amino Acids↗
PubMed1984

Clonal variability of PC12 pheochromocytoma cells with respect to catecholamine biosynthesis.

Clonal variants of PC12 cells with respect to catecholamine biosynthesis were isolated, and the catecholamine content was measured by high performance liquid chromatography with electrochemical detection. The dopamine content of 13 subclones, which were selected and isolated in tyrosine-free medium, was substantially higher than the control level: 0.91 +/- 0.10 nmol/mg protein (mean +/- SEM; n = 3). In contrast, the noradrenaline content showed a marked heterogeneity: only two subclones contained noradrenaline levels similar to or higher than the control level: 0.40 +/- 0.05 (n = 5). The rest of them contained below the level of 0.20, and only negligible amounts of noradrenaline were found in four subclones. Thus, the noradrenaline-to-dopamine ratio varied widely between 0.003:1 and 0.53:1. This divergence of the noradrenaline content appears to be related to differing levels of dopamine beta-monooxygenase activity. The administration of ascorbate to the medium alone, however, did not restore the level of noradrenaline to the normal level in a subclone. Heterogeneity of the response to applied glucocorticoid was also demonstrated.

Adrenal Gland Neoplasms↗
PubMed1984

Megakaryoblastic leukemia: the characterization and identification of megakaryoblasts.

This article describes three patients with megakaryoblastic leukemia, in whom the blast cells were identified as megakaryoblasts by the platelet peroxidase (PPO) reaction. More than 70% of the blasts in these patients were positive for the PPO reaction. Ultrastructurally, acid phosphatase activity in the megakaryoblasts was detected in the nuclear envelope, the endoplasmic reticulum, and in a few granules, but not in the Golgi cisternae. Some blast cells were identified by immunofluorescence or immunoalkaline phosphatase, using monoclonal antiplatelet glycoprotein IIb/IIIa antibody. In one patient, most of the blasts were positive for anti-HLA-DR monoclonal antibody. The possible order of the appearance of markers in the maturation of the megakaryocytic cell lineage is postulated, based on the data from the present cases and those previously reported. PPO activity appears in very immature cells, which retain Ia-like antigens. Platelet-specific glycoprotein IIb/IIIa is seen in immature cells that are only recognized by PPO activity.

Acute Disease↗
PubMed1984

Nucleosidediphosphate kinase in Escherichia coli: its polypeptide structure and reaction intermediate.

A nucleosidediphosphate kinase (NDP-kinase) has been highly purified from E. coli. The purified enzyme was found to have a molecular weight of approximately 64,000 daltons and be a 16,000 dalton polypeptide tetramer. The enzyme rapidly formed a phosphoenzyme when incubated with ATP in the presence of divalent cations such as Mg2+ and Ca2+ (1 mM) even at low temperatures (below 4 degrees C). The available evidence suggests that the phosphoenzyme is an enzyme-bound high energy phosphate intermediate, which functions as an intermediary in NDP-kinase action.

Amino Acids↗