Search PubMed⌕ Search

Biomedical subjects

T Endo

Publications and source records attributed to T Endo.

At least 901 records · Page 50Linked to original sources
PubMed1988

Carbohydrate binding specificity of immobilized Allomyrina dichotoma lectin II.

The carbohydrate binding specificity of Allomyrina dichotoma lectin II was investigated by analyzing the behavior of various complex type oligosaccharides and human milk oligosaccharides on an A. dichotoma lectin II-agarose column. Basically, the lectin interacts with the Gal beta 1----4GlcNAc group. Substitution of their terminal galactose residues by Neu5Ac alpha 2----6 will enhance their affinity to the lectin. By contraries, substitution at the C-2 or C-3 position of their terminal galactose with other sugars including sialic acid deprives their affinity to the lectin. With this characteristic, the immobilized lectin column can be used to separate complex type oligosaccharides with the Neu5Ac alpha 2----6Gal beta 1----4GlcNAc group from their isomeric oligosaccharides with the Neu5Ac alpha 2----3Gal beta 1----4GlcNAc group, where Neu5Ac is N-acetylneuraminic acid.

Animals↗
PubMed1988

Immunochemical characterization of adenocarcinoma-associated antigen YH206.

The antigen recognized by MAb YH206 is mainly expressed in adenocarcinomas and is also detected in the sera of cancer patients (Hinoda et al., 1987). This antigen (antigen YH206) was chemically characterized and purified by column chromatography. SDS-PAGE analysis revealed a broad component in the high-molecular-weight range which was clearly detectable by carbohydrate (PAS) but not by protein (silver) stain. Agarose gel electrophoresis and immunoblotting of antigen YH206 indicated that it consists of a high-molecular-weight component (more than 2,000 kDa). Treatment of antigen YH206 with alkali suggested that the antigenic determinant consists of carbohydrate chains of mucin type. Density gradient ultracentrifugation revealed that the activity of antigen YH206 is localized at a density of 1.45 g/ml, suggesting that antigen YH206 is a mucin. Neuraminidase treatment of antigen YH206 indicated that the epitope is cryptic and contains an asialocarbohydrate chain. Once antigen YH206 has been purified by affinity chromatography, neither CA19-9 antigen nor DU-PAN-II antigen can be detected, although they were present at very high levels in the crude ascitic starting material; these last two are representative carbohydrate antigens which are widely used for serodiagnosis to detect adenocarcinomas.

Adenocarcinoma↗
PubMed1988

[Effect of prostaglandins(PGs) on progesterone production by human cultured luteal cells and their ability of PGs production].

The present study was designed to investigate whether or not prostaglandins(PGs) were produced by human luteal cells(HLC) and their effects on the luteal cells by monolayer culture. The following results were obtained. Cultured HLC secreted progesterone(P), prostaglandin F(PGF) and prostaglandin E(PGE) into a medium at concentrations of 276.6 +/- 38.6, 1.95 +/- 0.36, 2.44 +/- 0.45 ng/ml/1 X 10(5) cells/day (mean +/- SE), respectively. Cultured HLC was able to convert 14C-arachidonic acid to 14C-PGF2 alpha, 14C-PGE2. These two results indicated that HLC had the ability to produce PGF and PGE. Cultures were carried out in the presence of indomethacin (Ind), PGF2 alpha and PGE2 alone as well as in a combination. P production by HLC was reduced in the presence of Ind. P production in the presence of Ind+PGE2 was more than that in the presence of Ind alone. There was no significant difference in P production between the presence of Ind and Ind+PGF2 alpha. It was concluded that HLC had the ability to produce PGs and that PGE2 significantly stimulated P production in as low concentrations as HLC could produce physiologically while PGF2 alpha did not.

Adult↗
PubMed1988

Immunohistochemical demonstration of S-100 protein in the brain neurosecretory cells of invertebrates (insects and earthworms).

This immunohistochemical study demonstrated the presence of S-100 protein (-like substance) in the nervous systems of some invertebrate animals. The immunoreactivity of S-100 protein was detected in some neurosecretory cells, but not in glial cells in the brains (cerebral ganglia) of silkworms, cockroaches and earthworms. The immunoreactive nerve fibers extended to the neurohemal organs. These results suggested the possibility that S-100 protein (-like substance) may act as a neurohormone or carrier protein in invertebrate animals.

Animals↗
PubMed1988

Substructure and higher structure of chicken smooth muscle alpha-actinin molecule.

Substructure of chicken gizzard smooth muscle alpha-actinin molecule was deduced by domainal mapping of the proteolytic fragments with alpha-chymotrypsin. There were three chymotryptic cleavage sites (Sites I, II, and III, from the amino terminus). Cleavage at Site I generated two fragments, i.e. an NH2-terminal 36-kDa fragment and a COOH-terminal 70-kDa fragment. The 70-kDa fragment generated either a 55-kDa fragment by cleavage at Site II or a 65-kDa fragment by cleavage at Site III. Purified NH2-terminal 36-kDa fragment bound to F-actin, whereas the 55-kDa fragment formed a dimeric molecule. Circular dichroism and electron microscopic experiments demonstrated that the alpha-helical content of the 55-kDa fragment was 14% higher than that of native gizzard alpha-actinin, coinciding with the apparently rod-shaped configuration of this fragment. A 110-kDa product was generated from two 55-kDa fragments in a cross-linking study with the zero-length cross-linker 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. Two cross-linkable sites in the 55-kDa, A- and B-site, were shown to be involved in this reaction. Further, it was demonstrated by using N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide labeling and immunoblotting analyses that the A-site on one 55-kDa fragment was cross-linked to the B-site on the other. These results suggest that smooth muscle alpha-actinin formed an antiparallel dimeric molecule in which the 55-kDa fragments connected the two actin-binding domains composed of the 36-kDa fragments.

Actinin↗
PubMed1988

Proton NMR resonance assignments and surface accessibility of tryptophan residues of a dimeric phospholipase A2 from Trimeresurus flavoviridis.

Proton NMR spectra of a dimeric phospholipase A2 from Trimeresurus flavoviridis have been recorded. N-1 proton resonances of the tryptophan indole rings have been detected and assigned to specific positions, Trp-3/Trp-30, Trp-68 and Trp-108, by comparing the spectra of the enzyme derivatives with tryptophans oxidized to differing extents. Photo-CIDNP experiments have revealed that Trp-68 and Trp-108 are exposed while Trp-3 and Trp-30 are buried in the molecule. This is consistent with the X-ray crystal structure of a homologous phospholipase A2 from Crotalus atrox where residues 3 and 30 are located at a dimer interface, but inconsistent with the results of stepwise oxidation of tryptophan residues.

Macromolecular Substances↗
PubMed1988

Latent membrane perturbation activity of a mitochondrial precursor protein is exposed by unfolding.

We have purified milligram amounts of an importable mitochondrial precursor protein [the presequence of yeast cytochrome oxidase subunit IV fused to mouse dihydrofolate reductase (DHFR)]. This has made it possible, for the first time, to perform detailed studies on the conformation of a precursor protein and its interaction with lipid membranes. The precursor protein closely resembled authentic mouse DHFR with respect to secondary structure (measured by CD spectra) and stability towards urea (measured by tryptophan fluorescence and enzyme activity). With this precursor protein, the presequence thus does not significantly alter the folding of the attached 'passenger protein'. In contrast to the corresponding presequence peptide, the native precursor exhibited only weak ability to disrupt vesicles with a low mol% of negatively charged lipids, suggesting that the passenger protein masks the amphiphilic properties of the presequence. The membrane-perturbing properties of the precursor were greatly enhanced by increasing the vesicles' content of negatively charged lipid or by denaturing the precursor in 5 M urea. Interaction with vesicles rich in acidic phospholipid was accompanied by partial unfolding of the precursor, suggesting that such a conformational change may also be involved in the interaction of the precursor with the mitochondrial membranes.

Animals↗
PubMed1988

Detection and localization of actin in Toxoplasma gondii.

The immunological cross-reactivity of the protein from whole-cell extracts of Toxoplasma gondii with antisera against actins from chicken-gizzard smooth muscle and from Ascaris body-wall muscle was demonstrated by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis (SDS-PAGE) and immunofluorescence studies. A protein of about 42 kDa, with the same mobility as that of rabbit smooth-muscle actin in SDS-PAGE showed cross-reactivity with anti-actin antisera on the electroblotted nitrocellulose sheet. Indirect fluorescent antibody staining of the parasites clearly showed that actin localized strongly in the anterior third of the organism in both extra- and intrahost cellular stages. From both a biochemical as well as structural point of view, the results obtained in the present experiments might explain the locomotive features of the parasite such as twirling and sliding, with most of the activity at the anterior end.

Actins↗
PubMed1988

Immunocytochemical localization of actin in Toxoplasma gondii.

The localization of actin in the trophozoites of Toxoplasma gondii was examined by means of immunogold staining for electron microscopy. The thin-sectioned specimens were incubated with the IgG fraction of polyclonal antibodies raised against Ascaris body-wall smooth-muscle actin following colloidal gold-conjugated protein A. Electron-dense gold particles were confined to the anterior polar region in the trophozoites: they were found in the conoid, preconoidal rings, possibly in the polar ring, and in the space between the anterior terminal of the inner membrane complex and conoid. The present experiments also suggest interactions of actin with subpellicular microtubules, leading to speculation that the association of actin with microtubules provides a link to myosin, a potential source of power for microtubule-dependent movements.

Actins↗
PubMed1988

Immunohistochemical localization of parvalbumin in rat and monkey autonomic ganglia.

The cellular distribution of parvalbumin-like immunoreactivity in autonomic ganglia such as superior cervical sympathetic ganglia, paravertebral sympathetic chain ganglia (T6), ciliary ganglia and enteric ganglia was investigated by immunohistochemical peroxidase-antiperoxidase methods using an antiserum against rat skeletal muscle parvalbumin. We detected parvalbumin-like immunoreactivity in almost all neurons of rat superior cervical sympathetic ganglia and other paravertebral sympathetic chain ganglia, where the antigen was located in the cytoplasm but the nuclei were not labelled. No neurons positive for parvalbumin-like immunoreactivity were observed in rat ciliary ganglia or enteric ganglia. In monkey, almost all neurons of the superior cervical sympathetic ganglia contained parvalbumin-like immunoreactivity, but none of the neurons of the ciliary ganglia were labelled with the antiserum to parvalbumin. These results suggest that parvalbumin-like immunoreactivity exists in a specific subpopulation of the neurons of the autonomic nervous system.

Animals↗
PubMed1988

Structural differences found in the sugar chains of eutopic and ectopic free alpha-subunits of human glycoprotein hormone.

Free alpha-subunits of human glycoprotein hormone were purified from the urine of a healthy pregnant woman and from that of a patient with adenocarcinoma. Comparative study of their sugar moieties revealed that they have different numbers and different sets of asparagine-linked sugar chains, which are also different from those of alpha-subunit obtained by dissociation of whole hCG molecule. The eutopic free alpha-subunit contained biantennary complex-type sugar chains only. In contrast, the ectopic free alpha-subunit contained tri- and tetraantennary complex-type sugar chains in addition.

Adenocarcinoma↗
PubMed1988

Evidence for a preferential iodination site within the thyroglobulin molecule.

Mouse 330 kDa thyroglobulin labeled in vivo was analyzed using a tryptic peptide mapping technique and high performance liquid chromatography (HPLC). 30 min after Na125I injection, one peptide spot (spot 7) on a silica gel plate was the only prominent labeled peptide, followed by other labeled peptide spots after 1 h. HPLC showed that spot 7 was rich in monoiodotyrosine. The ratios between the iodoamino acids were strictly maintained from 1 to 6 h after Na125I injection. Spot 7 was again the first spot that appeared from the samples of iodine-deficient mice. These data indicate that there is some preferential iodination site(s) within the thyroglobulin molecule and also that their iodoamino acid composition is predetermined.

Amino Acids↗
PubMed1988

Generation of multiple troponin T isoforms is a common feature of the muscles in various chordate animals.

1. Troponin T (TNT) expressed in various vertebrate skeletal and ascidian smooth muscles was examined by two-dimensional electrophoresis in combination with immunoblotting. 2. A monoclonal anti-TNT antibody, NT-302, exhibited binding ability to various TNT variants in the vertebrate and protochordate animals. 3. TNT isoform pattern differed among the animals, but the existence of multiple TNT isoforms in a single muscle tissue was the general feature of all the animals examined.

Animals↗
PubMed1988

A case of early cancer in the gallbladder: immunohistological analysis with monoclonal antibodies.

A case of early cancer in the gallbladder is reported. The tumor was disclosed as an echogenic nodular lesion with irregular margin by ultrasonography and endoscopic retrograde cholangiography. Among several tumor markers, CA19-9 showed a slightly higher level (51 U/ml). An operation was carried out because of the tumor size (over 10 mm) and the coexistence of a gallstone. The tumor was a well differentiated tubular adenocarcinoma. In the carcinoma tissue, CA19-9 and YH206 antigens showed different staining patterns, the latter antigen being detected by the monoclonal antibody, YH206, established in our laboratory. Although CA19-9 was strongly positive in the non-cancerous gallbladder epithelial cells, the YH206 antigen was negative. A slight elevation of the CA19-9 level in the patient's serum was probably caused by a diffusion of the CA19-9 antigen from the gallbladder epithelial cells to the serum, due to inflammation. On the other hand, it is interesting to note that the YH206 antigen was not demonstrated in the non-cancerous gallbladder epithelial cells but was in the cancer tissue.

Adenocarcinoma↗
PubMed1988

Structural study on the carbohydrate moiety of human placental alkaline phosphatase.

Alkaline phosphatase purified from human placenta contains a single asparagine-linked sugar chain in one molecule. The sugar chain was quantitatively liberated as radioactive oligosaccharides from the polypeptide moiety by hydrazinolysis followed by N-acetylation and NaB3H4 reduction, and separated by paper electrophoresis into one neutral and two acidic fractions. By a combination of sequential exoglycosidase digestion and methylation analysis, the structures of oligosaccharides in the neutral fraction were confirmed to be as follows: Gal beta 1----4GlcNAc beta 1----2Man alpha 1----6(Gal beta 1----4GlcNAc beta 1----2Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4(+/- Fuc alpha 1----6)GlcNAc. The acidic oligosaccharide fractions were mixtures of mono- and disialyl derivatives of the neutral fraction. All the sialic acid residues of the sugar chains occur as the NeuAc alpha 2----3Gal group. In the case of monosialyl derivatives, the N-acetylneuraminic acid was exclusively linked to the Man alpha 1----3 arm.

Alkaline Phosphatase↗
PubMed1988

Altered glycosylation is induced in both alpha- and beta-subunits of human chorionic gonadotropin produced by choriocarcinoma.

The two subunits of human chorionic gonadotropin (hCG) purified from the urine of a patient with choriocarcinoma were successfully separated by SDS-polyacrylamide gel electrophoresis. A comparative study of the oligosaccharides released from the two subunits by hydrazinolysis revealed that altered glycosylation occurs in both subunits and possibly at all four asparagine sites of the choriocarcinoma hCG molecule.

Asparagine↗