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Biomedical subjects

T Takegami

Publications and source records attributed to T Takegami.

At least 55 records · Page 3Linked to original sources
PubMed1990

Enzyme immunoassay for measuring antibodies against skeletal muscle in patients with myasthenia gravis.

We developed a highly sensitive enzyme immunoassay (EIA) for measuring IgG and IgM antibodies against human skeletal muscle (SM) component and tested sera from 100 patients with myasthenia gravis (MG), 59 with thymoma and 41 without thymoma. We found that the frequency of anti-SM IgG antibodies was significantly higher in MG patients with (81%) than without (37%) thymoma. The titers of the anti-SM IgG antibodies measured by EIA correlated well with those measured by RIA (r = 0.81, P less than 0.01). We also found that 12% of the myasthenic patients with thymoma and 15% without it had anti-SM IgM antibodies. There was no correlation between the titers of the IgG and IgM antibodies. Our EIA provides a measure of anti-SM antibodies that is of comparable sensitivity to that of RIA.

Antibodies, Anti-Idiotypic↗
PubMed1990

[A case of cranial polyneuropathy presenting with prominent facial diplegia, elevated serum Borrelia burgdorferi antibody and lymphocytic pleocytosis].

A 54 year-old male patient developed acute cranial polyneuropathy including prominent facial diplegia and radicular++-neuritis. He was proven to have lymphocytic pleocytosis, and elevated serum Borrelia burgdorferi antibody to X800 (normal; less than X200). A diagnosis of typical early neuro-borreliosis was made after these clinical and laboratory findings. This case is the first neuro-borreliosis showing the triad of neurological manifestations (meningitis, cranial neuritis, radicular++-neuritis) in Japan. It is concluded that neuro-borreliosis should be considered to be a cause of acute cranial polyneuropathy, particularly of facial diplegia, even if the patient has no apparent history of a tick bite.

Antibodies, Bacterial↗
PubMed1989

A temperature-sensitive defect of enterovirus 70 is located at the uridylylation of the genome-linked protein VPg in vitro.

The temperature-sensitive phenotype of enterovirus 70 (EV70) was examined by use of an in-vitro RNA replication system derived from a membrane fraction (crude replication complex, CRC) of EV70-infected HeLa cells. This system was capable of synthesizing the nucleotidyl proteins VPg-pU and VPg-pUpU. Formation of these nucleotidyl proteins was completely abolished when the in-vitro reaction was performed at the nonpermissive temperature for virus replication. Considering our previous observation that the defective stage of the temperature-sensitive growth of EV70 resides in the initiation step of RNA transcription in vivo, it is most likely that the lack of uridylylation of VPg at the restricted temperature in vitro is directly involved in the temperature-sensitive defect of virus growth in vivo.

Amino Acid Sequence↗
PubMed1989

In vitro synthesis of Japanese encephalitis virus (JEV) RNA: membrane and nuclear fractions of JEV-infected cells possess high levels of virus-specific RNA polymerase activity.

Japanese encephalitis virus (JEV)-specific RNAs (including 42S RNA) were synthesized in subcellular fractions prepared from infected C6/36 cells. This in vitro RNA synthesis essentially required Mg2+ and four ribonucleotides, and it was enhanced by K+. The amounts of RNA synthesized in vitro (in extracts from JEV-infected cells) increased as a function of time after infection. The RNA-synthetic activity in nuclear fractions was the highest among three kinds of subcellular fractions. Our data showed that nonstructural proteins NS3 and NS5 were membrane-associated proteins. In particular, NS3 was found almost exclusively in the nuclear and membrane fractions. Our results suggest that NS5 and NS3 may play specific role(s) in flavivirus RNA replication.

Animals↗
PubMed1989

[Reproduction of Japanese encephalitis virus in human glioma cells, 118MGC: inhibitory effect of host factor(s)].

Japanese encephalitis viruses (JEV) were well propagated in human glioma cells, 118MGC until the first 24 hrs after virus infection. However, after 24 hrs, virus growth rate was quickly reduced. This unusual pattern of virus growth was different from the cases in others cells, e.g. IMR-32, Vero and C6/36 cells. The fact that actinomycin-D retained the high yields of JEV in 118MGC cells suggests that some suppressing factors against JEV replication are produced in MGC cells. Interestingly, culture fluids of 118MGC cells indicated inhibitory effect to JEV reproduction, but other culture fluids from several cell lines had no effect. This inhibitory effect of the MGC-culture fluids was lost by heat-treatment at 60 C. In addition, the infectivity of JEV was rapidly decreased by the incubation with MGC-culture fluids. These findings suggest that 118MGC cells produce and secret some inhibitory factors against JEV replication.

Antiviral Agents↗
PubMed1988

Molecular cloning and complete nucleotide sequence of the genome of Japanese encephalitis virus Beijing-1 strain.

The genomic RNA of the Japanese encephalitis virus (JEV) Beijing-1 strain was reversely transcribed and the synthesized cDNA was molecularly cloned. Six continuous cDNA clones that cover the entire virus genome were established and sequenced to determine the complete nucleotide sequence of the JEV RNA. The precise genomic size was estimated as 10,965 bases long. With flanking 95 bases at the 5' and 583 bases at the 3' non-coding regions, one long open reading frame (ORF) was revealed encoding a virus polyprotein with 3,429 amino acid residues. Because of sequence homologies observed between JEV and other flaviviruses, the genome organization of JEV appears to be identical with other flaviviruses. Genetic variation detected among flavivirus genomes is consistent with the established serological relatedness between JEV and other members of flaviviruses. The secondary structure of the JEV genome is deduced and discussed concerning its involvement in genome replication.

Base Sequence↗
PubMed1986

Nucleotide sequence at the 3' end of Japanese encephalitis virus genomic RNA.

Japanese encephalitis (JE) virus genomic RNAs were purified from virions. Two hundred nucleotides at the 3' end of JE virus genomic RNA were directly sequenced by using reverse transcriptase. The nucleotide sequence at the 3' end of the viral RNA was conserved among four kinds of JE virus strains. The sequence has no AU-rich region that is present at the 3' termini of alphavirus RNAs. We also compared the nucleotide sequences at the 3' ends of RNAs from three different flaviviruses and found several common sequence elements. A secondary structure at the 3' end of JE virus genomic RNA was proposed that may be common among flavivirus genomic RNAs. Such structures and other common stretches of nucleotide sequences may be related to the biological properties of flaviviruses.

Base Sequence↗
PubMed1986

Initiation of poliovirus plus-strand RNA synthesis in a membrane complex of infected HeLa cells.

An in vitro poliovirus RNA-synthesizing system derived from a crude membrane fraction of infected HeLa cells was used to analyze the mechanism of initiation of poliovirus plus-strand RNA synthesis. This system contains an activity that synthesizes the nucleotidyl proteins VPg-pU and VPg-pUpU. These molecules represent the 5'-terminal structure of nascent RNA molecules and of virion RNA. The membranous replication complex is also capable of synthesizing nucleotidyl proteins containing nine or more of the poliovirus 5'-proximal nucleotides as assayed by the formation of the RNase T1-resistant oligonucleotide VPg-pUUAAAACAGp or by fingerprint analysis of the in vitro-synthesized RNA. Incubation of preformed VPg-pUpU with unlabeled nucleoside triphosphates resulted in the formation of VPg-pUUAAAACAGp. This reaction, which appeared to be an elongation of VPg-pUpU, was stimulated by the addition of a soluble fraction (S-10) obtained from uninfected HeLa cells. Preformed VPg-pU could be chased into VPg-pUpU in the presence of UTP. Our data are consistent with a model that VPg-pU can function as a primer for poliovirus plus-strand RNA synthesis in the membranous replication complex and that the elongation reaction may be stimulated by a host cellular factor.

Cell Membrane↗
PubMed1985

[Anti-triiodothyronine antibodies in patients with rheumatoid arthritis associated with Hashimoto's thyroiditis].

Anti-triiodothyronine antibody was found in a case of rheumatoid arthritis associated with Hashimoto's thyroiditis. The patient was a 40 year-old woman who had complained of polyarthralgia, joint-swelling and stiffness for seven years. She had a rheumatoid nodule and showed a positive RA test. Radiographic changes of hands and wrists showed osteoporosis, erosions and narrowing of joint space. Nonsteroidal anti-inflammatory drugs had been used for seven years. The diagnosis of Hashimoto's thyroiditis had been made by open biopsy of the thyroid gland seven years before. Serum T4, TSH, TBG, free T4, free T3 and r-T3 were all normal. On the other hand, serum T3 level was almost unmeasurable by radioimmunoassay. Binding of 125I-T3 to the patient's serum was studied by using polyethylene glycol (PEG) and column chromatography. By using the PEG method, the binding of 125I-T3 to the patient's serum was tenfold compared to control serum. Sephadex G-25 column chromatography (0.9 X 1.5 cm) of 125I-T3 with the patient's serum in the presence of 0.1% ANS showed an early radioactive peak, while control serum did not show an early peak. In the next experiments, the patient's serum was labelled with 125I-T3, mixed with human anti-IgG, IgM, IgA, lambda, kappa, incubated at 4 degrees C for 20 hours and centrifuged for 20 min. Strong binding to the anti-IgG and anti-lambda was detected. The presence of this abnormal T3-binding globulin in the patient's serum may have produced an undetectable T3 level.

Adult↗
PubMed1983

Membrane fractions active in poliovirus RNA replication contain VPg precursor polypeptides.

The poliovirus specific polypeptide P3-9 is of special interest for studies of viral RNA replication because it contains a hydrophobic region and, separated by only seven amino acids from that region, the amino acid sequence of the genome-linked protein VPg. Membraneous complexes of poliovirus-infected HeLa cells that contain poliovirus RNA replicating proteins have been analyzed for the presence of P3-9 by immunoprecipitation. Incubation of a membrane fraction rich in P3-9 with proteinase leaves the C-terminal 69 amino acids of P3-9 intact, an observation suggesting that this portion is protected by its association with the cellular membrane. These studies have also revealed two hitherto undescribed viral polypeptides consisting of amino acid sequences of the P2 and P3 regions of the polyprotein. Sequence analysis of stepwise Edman degradation show that these proteins are 3b/9 (Mr 77,000) and X/9 (Mr 50,000). 3b/9 and X/9 are membrane bound and are turned over rapidly and may be direct precursors to proteins P2-X and P3-9 of the RNA replication complex. P2-X, a polypeptide void of hydrophobic amino acid sequences but also found associated with membranes, is rapidly degraded when the membraneous complex is treated with trypsin. It is speculated that P2-X is associated with membranes by its affinity to the N-terminus of P3-9.

Amino Acid Sequence↗
PubMed1983

Membrane-dependent uridylylation of the genome-linked protein VPg of poliovirus.

A small nucleotidyl-protein has been synthesized in vitro in a membrane fraction of poliovirus-infected HeLa cells. Analyses of the nucleotides and polypeptide have shown that the nucleotidyl-protein is VPg-pUpU: the genome-linked protein of poliovirion RNA covalently bound to the first two 5'-terminal nucleotides of poliovirus RNA. Synthesis of VPg-pUpU in vitro was sensitive to nonionic detergent. We suggest that VPg-pUpU is part of the initiation complex in poliovirus RNA replication in a membranous environment.

Genes↗
PubMed1982

Biological activities of the structural proteins of Japanese encephalitis virus.

Structural proteins V1, V2 and V3 of Japanese encephalitis virus (JEV) were isolated and purified by means of polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS) and extracted from the sliced gel. The purified and renatured V3 envelope protein was found to bind to receptors for JEV on red blood cells. V3 also bound to haemagglutination inhibition (HI) antibodies from anti-JEV sera. In addition, V3 protein induced neutralizing antibodies against JEV when injected into mice. These facts strongly suggest that V3 protein carries the antigenic epitope(s) that elicit neutralizing antibodies and react with HI antibodies. We conclude the V3 plays an important role in virus infection. V2 protein did not exhibit these biological activities, but antibody against V1 protein, not contaminated with V3 protein, showed slight virus neutralizing activity. Possible implications of these results are discussed.

Animals↗
PubMed1982

Differences in biological activity of the V3 envelope protein of two Japanese encephalitis virus strains.

Two stains Nakayama-NIH and JaGAr-01 of Japanese encephalitis virus (JEV) distinctly differ in their virulence. Amino acid analysis of the V3 viral protein revealed different serine and tyrosine contents in JaGAr-01 V3 as compared to Nakayama -NIH V3. SDS-PAGE purified renatured JaGAr- and Nakayama-V3 proteins could absorb cross-reactive neutralizing antibodies present in anti-nakayama and anti-JaGAr hyperimmune sera. They also absorbed strain specific antibodies of anti-JaGAr and anti-Nakayama sera, respectively. These observations clearly suggest that both JEV strain specific and cross reactive antigenic determinants are present on V3 protein molecules. Antibody against purified Nakayama V3 protein neutralized Nakayama-NIH virus, but had little neutralizing activity against JaGAr-01 virus. The phenomenon is less pronounced when antibodies against Nakayama-NIH virions are used rather than those against purified homologous V3. This suggests that the antigenicity of the purified V3 protein differs from that of the intact virus envelope.

Amino Acids↗
PubMed1981

Binding of [35S]saccharin to a protein fraction of rat tongue epithelia.

The binding of [35S]saccharin to ammonium sulfate fractions from homogenates of rat tongue epithelia was measured by equilibrium dialysis. The 40--60% saturated ammonium sulfate fraction from the buffer-soluble fraction had the highest saccharin-binding activity. Binding of [35S]saccharin to the 40--60% ammonium sulfate fraction was inhibited by unlabeled saccharin sodium salt. The inhibition increased with increasing unlabeled saccharin concentration and was nearly complete above 10 mM. [35S]Saccharin binding to the 40--60% ammonium sulfate fraction extracted from the tongue epithelia was inhibited by glucose, lactose and sucrose, while binding to similar fractions from tongue muscle was not affected by these sugars. The inhibition of binding of labeled saccharin to the epithelial fraction increased with increasing glucose concentrations. About 35% of the binding was inhibited by 1 M glucose. No significant difference in the amount of inhibition was seen among the three sugars at 0.1 M. The 40--60% ammonium sulfate fraction from tongue epithelium devoid of taste buds bound much less [35S]saccharin than did a similar fraction from epithelium with taste buds. Binding of [35S]saccharin by the preparation from epithelium devoid of taste buds was not inhibited by glucose. The results provide evidence that the 40--60% ammonium sulfate fraction from tongue epithelia with taste buds contains a protein which binds saccharin and sugars. We hypothesize that it is a sweet taste receptor protein.

Animals↗
PubMed1981

A silent period in sural muscle occurring prior to the voluntary forward inclination of the body.

A silent period lasting for 300-500 msec was observed in triceps surae muscle when the subject inclined forward from the normal standing. This silent period preceded 100 msec or more the beginning of the body inclination and was terminated by an abrupt refiring in the midst of the body swing. The silence was not preceded by the increase in activity of the sural muscle itself or any other leg muscles studied. H-reflex in soleus was strongly inhibited or disappeared during the silent period, indicating that the excitability of the spinal motoneurons was greatly decreased during this period. These findings suggest that the silent period was not induced by some reflex activity in the spinal cord, but was caused by the inhibitory activity based on a central program on the spinal motoneurons.

Adult↗