[Idiopathic thrombocytopenic purpura, associated with deep vein thrombosis induced by tranexamic acid].
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Aged↗
Biomedical subjects
Y Endo
Publications and source records attributed to Y Endo.
[A case of arrhythmogenic right ventricular dysplasia with abnormal Q waves in ECG].
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Adult↗
Production of human thyroid-stimulating hormone in Chinese hamster ovary cells.
Human thyroid-stimulating hormone (hTSH) has been produced in Chinese hamster ovary (CHO) cells co-transformed with two plasmids: one carrying the alpha subunit cDNA with mouse dihydrofolate reductase gene and the other carrying hTSH beta subunit cDNA. Each cDNA was driven to expression under the control of SV40 early promoter. hTSH and its alpha subunit were secreted into culture media, and their secretion increased with exposure of the cells to increasing concentrations of methotrexate. Gel filtration analysis revealed that the molecular size of the hTSH was the same as that of natural hTSH. Furthermore, the CHO cell-produced hTSH elevated the cyclic AMP level in the rat thyroid cell line FRTL-5 in the same manner as natural hTSH does.
Animals↗
GFA-protein gene expression on the astroglia in cow and rat brains.
The distribution of messenger RNA for glial fibrillary acidic protein (GFA-protein) of cow and rat brains was studied by an in situ hybridization technique using a tritium-labeled cDNA probe and autoradiography. The results were compared to the findings of GFA-protein immunohistochemistry. The signals of GFA-protein mRNA were detected on the perikaryal cytoplasm of astroglia observed in the following areas: the subpial area and the white matter of the cerebrum and cerebellum of the cow and the rat; gray matter of cow spinal cord; the thalamus, pontine reticular formation and white matter of the rat brainstem. All of these areas contain astroglia which are strongly positive for GFA-protein immunohistochemistry. On the other hand, we could detect no GFA-protein mRNA-positive glial cells in the areas where astroglia are negative for this immunostaining. These results indicate that the regional differences in the amount of GFA-protein in astroglia depend primarily on the degree of expression of their GFA-protein gene.
Animals↗
Electron microscopic study on S-100 protein-immunoreactive cells in the guinea pig duodenum, with special reference to the interstitial cells of Cajal.
S-100 protein-immunoreactive cells were studied in the nervous system of the guinea pig duodenum by pre-embedding immunoelectron microscopic cytochemistry. Immunoreactivity of S-100 protein was found diffusely in the cytoplasm of enteroglial cells in the ganglia, nerve strands and autonomic ground plexus. There were fibroblast-like cells containing no S-100 protein immunoreactivity around the ganglia and nerve bundles. Relationship between the fibroblast-like cells and the interstitial cells of Cajal was discussed.
Animals↗
RNA N-glycosidase activity of ricin A-chain. Mechanism of action of the toxic lectin ricin on eukaryotic ribosomes.
The modification reaction of 28 S rRNA in eukaryotic ribosomes by ricin A-chain was characterized. To examine whether ricin A-chain release any bases from 28 S rRNA, rat liver ribosomes were incubated with a catalytic amount of the toxin, and a fraction containing free bases and nucleosides was prepared from the postribosomal fraction of the reaction mixture by means of ion-exchange column chromatography. Thin-layer chromatographic analysis of this fraction revealed a release of 1 mol of adenine from 1 mol of ribosome. When the ribosomes or naked total RNAs were treated with ricin A-chain in the presence of [32P] phosphate, little incorporation of the radioactivity into 28 S rRNA was observed, indicating that the release is not mediated by phosphorolysis. Thus, considering together with the previous result (Endo, Y., Mitsui, K., Motizuki, M., and Tsurugi, K. (1987) J. Biol. Chem. 262, 5908-5912), the results in the present experiments demonstrated that ricin A-chain inactivates the ribosomes by cleaving the N-glycosidic bond of A4324 of 28 S rRNA in a hydrolytic fashion.
Animals↗
The mechanism of action of ricin and related toxic lectins on eukaryotic ribosomes. The site and the characteristics of the modification in 28 S ribosomal RNA caused by the toxins.
Ricin is a potent cytotoxic protein derived from the higher plant Ricinus communis that inactivates eukaryotic ribosomes. In this paper we have studied the mechanism of action of ricin A-chain on rat liver ribosomes in vitro. Our findings indicate that the toxin inactivates the ribosomes by modifying both or either of two nucleoside residues, G4323 and A4324, in 28 S rRNA. These nucleotides are located close to the alpha-sarcin cleavage site and become resistant to all ribonucleases tested. The examination of the lability of phosphodiester bonds of these nucleotides to both mild alkaline digestion and aniline treatment at acidic pH suggests that the base of A4324 is removed by the toxin. This unique activity of ricin A-chain was also observed when naked 28 S rRNA is used as a substrate, indicating that the toxin directly acts on the RNA. Similar activity on 28 S rRNA is also exhibited by abrin and modeccin, ricin-related toxins, suggesting a general mechanistic pathway for ribosome inactivation by lectin toxins.
Animals↗
Oncostatic and immunomodulatory effects of a glycoprotein fraction from water extract of abalone, Haliotis discus hannai.
The liquid from heat-treatment of an abalone, Haliotis discus hannai, which is normally discarded as waste, was found to contain a new glycoprotein antineoplastic agent. A fraction of the liquid obtained from chromatography that was 22% carbohydrate and 44% protein was injected locally or systemically into ICR mice or BALB/c mice inoculated s.c. with allogeneic sarcoma 180 or syngeneic Meth-A fibrosarcoma, and growth of the tumors was strongly inhibited. There was an optimum dose range for the inhibition of the growth of sarcoma 180, and optimum timing. The fraction did not have antitumor activity in T cell-deficient nude mice (CD-1 nu/nu or BALB/c nu/nu mice), and administration of carrageenan in vivo decreased its activity in ICR mice. This fraction activated the cytostatic activity of peritoneal and alveolar macrophages in vivo. These results suggest that the antitumor activity is not due to a direct toxic effect but to stimulation of a host-mediated response.
Adjuvants, Immunologic↗
A new radioimmunoassay of free thyroxine using 125I-labelled thyroxine-protein complex uninfluenced by albumin and thyroxine-binding globulin.
We describe a double-antibody solid phase radioimmunoassay for free thyroxine (FT4) in serum with use of 125I-labelled thyroxine-human chorionic gonadotropin conjugate. Since the labelled conjugate does not bind to thyroxine binding globulin (TBG) and albumin because of its large molecular weight, the method is uninfluenced by TBG or albumin. The measurable range of FT4 in serum was 2.0 to 128 ng/l. The mean coefficients of variation within and between assays were 4.6-8.6% and 6.3-11.6%, respectively. The FT4 values determined by the proposed method correlated well with those determined by commercial radioimmunoassay in subjects with normal albumin concentration (r = 0.98). The FT4 concentrations in serum as determined by this method were 9 to 17 ng/l for healthy adult subjects; high for patients with hyperthyroidism; low for patients with hypothyroidism; and within normal limits for pregnant women, and patients with high or low concentrations of thyroxine-binding globulin.
Albumins↗
Effects of phorbol esters and a diacylglycerol on mouse eggs: inhibition of fertilization and modification of the zona pellucida.
Sperm penetration of the zona pellucida and fertilization are inhibited in mouse eggs treated with phorbol esters and the diacylglycerol, sn-1,2-dioctanoyl glycerol. The effect appears mediated by the zona pellucida, since zona-free eggs treated with these compounds are fertilized to the same extent as untreated eggs. Moreover, the binding of sperm to isolated zonae incubated in the absence or presence of biologically active phorbol esters is similar. Last, sperm treated with phorbol esters or sn-1,2-dioctanoyl glycerol bind to eggs and undergo the acrosome reaction to the same extent as untreated sperm. The inhibitory effect on fertilization is correlated with an egg-induced modification of at least ZP2, as manifested by a change in its electrophoretic mobility in polyacrylamide gels. In addition, changes in the biological properties of the treated zonae occur, such that sperm binding is not altered, but that the final stage(s) of the zona-induced acrosome reaction is inhibited. Zonae obtained from phorbol ester- or diacylglycerol-treated eggs should provide a system to study both the structural modifications of the zona proteins that are involved in induction of the acrosome reaction, as well as, delineating the sequence of events that comprise the acrosome reaction.
Acrosome↗
Evidence for the role of a guanine nucleotide-binding regulatory protein in the zona pellucida-induced mouse sperm acrosome reaction.
Recently, it has been demonstrated that mouse sperm contain a protein with properties similar to the inhibitory guanine nucleotide-binding regulatory protein, Gi (Kopf, G. S., Woolkalis, M. J., and Gerton, G. L. 1986. J. Biol. Chem. 261, 7327-7331). Since sperm-zona pellucida interaction represents a specialized form of intercellular communication and signal transduction we examined the role of the mouse sperm Gi-like protein in the zona pellucida-induced acrosome reaction using mechanically isolated, structurally intact zonae pellucidae. Sperm capacitated for 90 min in the presence of increasing concentrations of islet-activating protein (IAP) bind to the zona pellucida to a similar extent as control sperm incubated in the absence of this toxin. The zona pellucida-induced acrosome reaction, however, is inhibited in a concentration dependent manner by IAP, with half-maximal effects at 0.1-1.0 ng/ml IAP. IAP does not affect the ability of the sperm to become capacitated, but inhibits the cells from progressing into an intermediate stage prior to the completion of the acrosome reaction. When sperm are capacitated in the presence of 100 microM guanosine-5'-O-(3-thiotriphosphate) for 60 min prior to the addition of IAP during the final 30 min, the IAP-induced inhibition of the zona pellucida-induced acrosome reaction is abolished; capacitation in the presence of 100 microM guanosine-5'-O-(2-thiodiphosphate) does not abolish the inhibitory effects of IAP. The target of the IAP effect on intact sperm appears to be at the level of the Gi-like protein since IAP-catalyzed 32P-ADP-ribosylation of the Mr = 41,000 substrate in detergent extracts of sperm is reduced when intact sperm are preincubated with IAP during capacitation. These data suggest that the mouse sperm Gi-like protein plays an intermediary role in the zona pellucida-induced acrosome reaction.
Acrosome↗
Effects of a phorbol ester on mouse eggs: dissociation of sperm receptor activity from acrosome reaction-inducing activity of the mouse zona pellucida protein, ZP3.
Biologically active phorbol esters or a diacylglycerol induce mouse eggs to modify the zona pellucida such that sperm receptor activity is retained but the ability of bound sperm to undergo a complete acrosome reaction is lost (Y. Endo, R.M. Schultz, and G.S. Kopf. 1987. Dev. Biol. 119, 199-209). We now show that purified ZP3 from 12-O-tetradecanoyl phorbol-13-acetate (TPA)-treated eggs possesses full sperm receptor activity but has lost its ability to induce a complete acrosome reaction. The modification of the acrosome reaction-inducing activity of ZP3 from these TPA-treated eggs differs from ZP3 isolated from two-cell embryos, which cannot initiate the acrosome reaction. These results demonstrate the dissociation of the two biological activities of ZP3 and may provide a system to assess the components of ZP3 involved in the acrosome reaction.
Acrosome↗
Inhibitory effect of acupuncture on the finger flexion reflex induced by finger tip vibration.
The effect of acupuncture on finger flexion reflex, caused by mechanical vibration applied to the finger tip, was studied by using the cross-correlation function. A stainless steel acupuncture needle was inserted into the acupuncture point called "Wai-Kuan" for 10 min. Acupuncture inhibited the reflex and suppressed the two modes seen in the cross-correlogram between unitary EMG activity of the muscle flexor digitorum superficialis and finger tip vibration with random frequency. The recovery of the primary mode, which may be via the spinal monosynaptic reflex loop, was significantly earlier than the recovery of the secondary mode, which may be via the supraspinal reflex long loop. This suggests that the distinct inhibitory effect of acupuncture takes place on the reflex at spinal and supraspinal levels.
Action Potentials↗
Newly synthesized analogues of the spider toxin block the crustacean glutamate receptor.
Effects of synthetic compounds similar to the structure of a spider toxin were studied on the glutamate receptors in crustacean neuromuscular synapses. Two kinds of analogues, 2,4-dihydroxyphenylacetyl-asparaginyl cadaverine (C-1) and 2,4-dihydroxyphenylacetyl-asparaginyl spermine (C-2), suppressed the excitatory postsynaptic potentials in a manner similar to natural spider toxin (JSTX). The dose-response relationship showed that the relative potency of the compounds is C-1 less than C-2 less than JSTX. While the effect of JSTX was irreversible, those of C-1 and C-2 were reversible. These synthetic compounds may serve as important tools in studying the structure and function of glutamate receptors.
Animals↗
Characterization of a novel acidic protein of 38 kDa, A0, in yeast ribosomes which immunologically cross-reacts with the 13 kDa acidic ribosomal proteins, A1/A2.
A new ribosomal protein of 38 kDa, named A0, was detected in yeast ribosomes on immunoblotting. The antibody used here was that against A1/A2, 13 kDa acidic ribosomal proteins which cross-reacted with A0. Although A0 and A1/A2 share common antigenic determinants, they differ in the following biochemical properties. While A1/A2 could be extracted from ribosomes with ethanol and ammonium sulfate, A0 could not. A0 gave two protein spots in a less acidic region than for A1/A2 on two-dimensional gel electrophoresis. The heterogeneity observed for A0 was ascribable to phosphorylation because one spot disappeared after treatment of the ribosomes with phosphatase. The syntheses of A0 and A1/A2 are directed by different mRNA species, as judged with a cell-free translation system, ruling out the possibility that A0 is a precursor of A1/A2. Although a mammalian ribosomal protein equivalent to A0 has been shown to be associated with 13 kDa acidic proteins in the cytoplasm, essentially no A0 was detected on immunoblotting in the yeast cytosol, while a small but detectable amount of A1/A2 was present. The possibility that A0 is a eukaryotic equivalent of L10 of Escherichia coli is discussed.
Cytosol↗
Suppression and potentiation of 5-hydroxytryptophan-induced hypoglycaemia by alpha-monofluoromethyldopa: correlation with the accumulation of 5-hydroxytryptamine in the liver.
Experiments were done to examine whether the accumulation of 5-hydroxytryptamine (5-HT) in the liver is responsible for the hypoglycaemia induced in mice by 5-hydroxytryptophan (5-HTP) and lipopolysaccharides (LPS). (+/-)-alpha-Monofluoromethyldopa (FMD), a potent irreversible inhibitor of aromatic amino acid decarboxylase, suppressed the 5-HTP-induced accumulation of 5-HT in the liver at a dose of 2 mg kg-1 or more, but potentiated the accumulation at lower dose of 0.4 mg kg-1. Corresponding to these effects, the hypoglycaemic response was prevented by the higher doses of FMD and potentiated by the lower dose. These contrasting effects of FMD were explicable by the amounts of 5-HTP entering the liver. In contrast, FMD did not prevent either the hypoglycaemia or the accumulation of 5-HT in the liver induced by LPS. These results further support the hypothesis that the accumulation of 5-HT in the liver is causally related to the hypoglycaemia induced by 5-HTP and indicate that the LPS-induced 5-HT accumulation in the liver is not derived from stimulation of 5-HT synthesis. It is still not clear whether the accumulation of 5-HT in the liver is involved in the hypoglycaemic response to LPS.
5-Hydroxytryptophan↗
Antimicrobial activity of tertiary amine covalently bonded to a polystyrene fiber.
Tertiary amine was covalently bonded to a polystyrene fiber and examined for antibacterial activity. The tertiary amine covalently bonded to a polystyrene fiber (TAF) showed a high antimicrobial activity against Escherichia coli. TAF exhibited a stronger antibacterial activity against gram-negative bacteria (E. coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhimurium, and Serratia marcescens) than against gram-positive bacteria (Staphylococcus aureus and Streptococcus faecalis) or Candida albicans. This activity against E. coli was accentuated by 0.1% deoxycholate or 10 mg of actinomycin D per ml, to which E. coli is normally not susceptible. This implies that TAF causes an increase of the bacterial outer membrane permeability. On the other hand, the antimicrobial activity was inhibited by adding Mg2+ or by lowering the pH. This suggest an electrostatic interaction between the bacterial cell wall and TAF. Scanning electron microscopy showed that E. coli cells were initially attached to TAF, with many projections on the cell surface, but then were apparently lysed after contact for 4 h. Taken together, these results imply that bacteria initially interact with TAF by an electrostatic force between the anionic bacterial outer membrane and the cationic tertiary amine residues of TAF and that longer contact with TAF damages the bacterial outer membrane structure and increases its permeability.
Anti-Bacterial Agents↗
An unclassified platelet function disorder associated with bleeding tendency.
A 7-year-old boy with a history of bleeding tendency showed a prolongation of bleeding time and a decrease in platelet adhesiveness. The platelets of the patient, however, had a normal reaction to ADP, collagen, epinephrine, arachidonic acid, bovine fibrinogen, ristocetin, A-23187 and thrombin-induced aggregation, and their shape was determined by electron microscopy to be normal. Therefore, this disorder could not be thought to belong to any known platelet dysfunction. On the other hand, an increase in clot retraction, a reversal of ATP/ADP, a decrease in beta-thromboglobulin and platelet factor 4 in the platelets, and an elevation of plasma levels of released beta-thromboglobulin from the platelets were observed in the patient. We don't know any cases with such an association of hypo- and hyperfunction of platelets.
Adenosine Diphosphate↗