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Biomedical subjects

T Takegami

Publications and source records attributed to T Takegami.

At least 19 recordsLinked to original sources
PubMed1997

Theiler's murine encephalomyelitis virus subgroup strain-specific infection in a murine macrophage-like cell line.

We compared infection of a murine macrophage-like cell line, J774-1, with two Theiler's murine encephalomyelitis virus subgroup strains. The GDVII strain, which is highly virulent and produces acute polioencephalomyelitis in mice, did not actively replicate in J774-1 cells, although there was a significant inhibition in cellular protein synthesis. In contrast, the DA strain, which is less virulent and causes demyelination with a persistent virus infection, productively infected J774-1 cells; however, there was less virus produced than in BHK-21 cells, and there was little if any cellular protein shutoff. These in vitro data may provide some explanation for the biological activities that are observed between both subgroup strains.

Actins↗
PubMed1995

Japanese encephalitis virus nonstructural protein NS3 has RNA binding and ATPase activities.

Sequence data suggest that Japanese encephalitis virus (JEV) protein NS3 is a multifunctional protein with sequence motifs characteristic of a protease and a helicase. To examine the functions of JEV-NS3, a fusion protein of NS3 in Escherichia coli was generated. Analysis by Western blot using monospecific rabbit antisera generated against the fusion protein (anti-MBJEN3) showed that NS3 was localized in the membrane fraction of JEV-infected cells and the particulate fraction of bacteria extracts. The addition of anti-MBJEN3 sera reduced JEV-specific RNA synthesis activity in a in vitro system. In addition, NS3 was shown to exhibit RNA binding and ATPase activities, suggesting this protein has an important role in viral RNA replication in virus-infected cells.

Adenosine Triphosphatases↗
PubMed1995

Hepatitis C virus nonstructural protein NS3 transforms NIH 3T3 cells.

Clinical evidence suggests that hepatitis C virus (HCV) is etiologically involved in hepatic cancer and liver cirrhosis. To investigate whether the HCV nonstructural protein NS3 has oncogenic activity, NIH 3T3 cells were transfected with an expression vector containing cDNA for the 5'- or 3'-half sequence of the HCV genome segment encoding NS3. Only cells transfected with the 5'-half cDNA rapidly proliferated, lost contact inhibition, grew anchorage independently in soft agar, and formed tumors in nude mice. PCR analysis confirmed the presence of the 5'-half DNA in the transfectants. These results suggest that the 5' region of the HCV genome segment encoding NS3 is involved in cell transformation.

3T3 Cells↗
PubMed1994

Different antibody response to a neutralizing epitope of human cytomegalovirus glycoprotein B among seropositive individuals.

The amino-terminal portion of human cytomegalovirus glycoprotein B (HCMV-gB) was expressed as a fusion protein to analyze the neutralizing epitope recognized by human monoclonal antibody C23 and the humoral immune response to this epitope. The linear neutralizing epitope was further localized to the peptide within 17 amino acids (position 68-84) which were conserved between two HCMV laboratory strains. Ten out of 17 HCMV-seropositive human sera contained the antibody against this epitope. Although seven sera were negative for reacting with the fusion protein, the viruses isolated from the same patients retained the epitope. The immunogenicity of the epitope and the possible application of C23 human monoclonal antibody for passive immunization against HCMV infections are discussed.

Amino Acid Sequence↗
PubMed1994

Detection of human cytomegalovirus genome in uterus tissue.

To analyze persistent infection by human cytomegalovirus (HCMV) in vivo, specimens obtained from various sources and autopsied organs were examined for the presence of HCMV DNA, mRNA transcripts and antigens by polymerase chain reaction, in situ hybridization and immunostaining. The HCMV genome was detected in lung, liver, kidney, and blood vessels at an average positive rate of 15%. The highest PCR-positive rate was observed with cervical smears. Subsequent examination of uterus tissues from patients with myoma revealed HCMV transcripts and antigens in glandular epithelial cells, leukocytes, endothelial cells, and others, indicating productive HCMV infection of cervical tissue.

Adrenal Glands↗
PubMed1994

Molecular comparison of dengue type 1 Mochizuki strain virus and other selected viruses concerning nucleotide and amino acid sequences of genomic RNA: a consideration of viral epidemiology and variation.

Dengue-1 (D1) Mochizuki strain was examined for its nucleotide and amino acid sequences of genomic RNA and the data obtained were compared with those of other selected virus strains reported previously. Genomic regions corresponding to C, preM and M proteins were the major subjects of study. Parts of E protein were additionally examined. Among the D1 viruses investigated, the Mochizuki virus which was isolated in 1943 in Japan was shown to be close to Philippine 836-1 strain isolated in 1984 and Nauru Island strain isolated in 1974 at the respective places, in contrast with Thai AHF 82-80 strain isolated in 1980 and Caribbean CV1636/77 strain isolated in 1977. At the same time, a difference was noted between the Mochizuki and Philippine/Nauru strains at the cleavage site of preM/M junction: Mochizuki possessed RRGKR/S sequence whereas the Philippine/Nauru had RRDKR/S. The glycosylation site in preM and hydrophobic regions at the carboxyl termini of M and E were well conserved. Significances of the data are discussed in connection with viral epidemiology and variation.

Amino Acid Sequence↗
PubMed1994

Immunoadsorption therapy for myasthenia gravis.

The results of a multicentre trial were analysed to evaluate the efficacy of immunoadsorption therapy for severe generalised myasthenia gravis. Twenty patients with myasthenia gravis who were concurrently receiving high dose prednisolone and azathioprine therapy were treated with an affinity-type adsorbent, using tryptophan-linked polyvinyl alcohol gel (IM-TR), according to a standardised treatment protocol. The 20 patients received five adsorption treatments within a period of 10 days. In 11, pronounced improvement of myasthenic weakness was seen and long-term remission was maintained. The treatment was especially effective in patients with thymic hyperplasia. Circulating acetylcholine receptor (AChR) antibodies were reduced by about 60% by treating one plasma volume. There was no difference in the rate of removal of the AChR antibodies between patients with thymic hyperplasia and patients with thymoma. No serious complications occurred during 100 procedures. It was concluded that the immunoadsorption therapy with IM-TR is useful in controlling symptoms in patients with severe myasthenia gravis who are otherwise unresponsive.

Adolescent↗
PubMed1993

Localization and functions of Japanese encephalitis virus nonstructural proteins NS3 and NS5 for viral RNA synthesis in the infected cells.

Recently it has been reported that Japanese encephalitis virus (JEV)-specific RNAs can be synthesized in vitro in the subcellular fraction including outer-nuclear membrane (Takegami and Hotta, 1989). The results of Western blot analysis and indirect immunofluorescence test using two kinds of monospecific antisera against JEV nonstructural proteins NS3 and NS5 showed that NS3 and NS5 were membrane-associated proteins and formed the complex at the perinuclear site in the infected cells. Both antisera against NS3 and NS5 inhibited in vitro RNA synthesis. These results suggest that NS5 and NS3 play important role(s) in flavivirus RNA replication.

Animals↗
PubMed1993

Remission of myasthenia gravis: clinical, electrophysiological and immunological studies.

The prognosis of 142 patients with myasthenia gravis (MG) was clinically investigated. Forty-nine (35%) had clinical remission (CR) and 23 (16%) good improvement (GI), while 70 (49%) remained in poor condition. Favorable clinical factors for CR were the onset of MG before the age of 20 years, a pre-thymectomy period of less than one year, and a post-thymectomy period of six years or more. Single-fiber electromyography (SFEMG) showed abnormal jitter in nine (47%) of the 19 CR patients, while abnormal jitter was shown in 13 (81%) of the 16 GI patients. Abnormal jitter in CR patients was correlated with the following clinical factors: complication with the thymoma, a period of three or more years from thymectomy to remission, and a remission period of less than six years. An anti-acetylcholine receptor (anti-AChR) antibody was positive in 12 CR patients (63%) as well as in 13 GI patients (81%). Based upon these facts, we point out that true remission seldom occurs in MG patients, and that there exist clinical features that may favorably induce clinical remission. We would like to postulate that electrophysiological and immunological follow-up is indispensable even in CR patients to predict recurrence.

Adult↗
PubMed1993

[A form of dopa-responsive dystonia of late onset with diurnal fluctuations].

We report a case of a 67-year-old woman who had dopa-responsive dystonia of late onset with diurnal fluctuations. She was well until the age of 65 years, when she noted the insidious onset of involuntary movements mainly involving the neck and trunk. She had no family history of movement disorders and had never received neuroleptics. Two years after her symptoms began, she visited our clinic. Neurological examination revealed slow repetitive extension and flexion movements of the neck and trunk, and irregular slow movements involving the mouth, tongue and limbs. The cranial nerves, cerebellar function, muscle strength, deep reflexes and sensory function were intact. Clinically and electromyographically, dystonia was characteristic of her involuntary movements. No parkinsonian features were present. The involuntary movements showed diurnal fluctuations that improved after sleep and the administration of L-DOPA and trihexyphenidyl. Dopamine receptor blocking agents aggravated her condition. Routine blood chemistry including copper metabolism, cerebrospinal fluid findings, and brain CT scan were all normal. Dopa-responsive dystonia is characterized by onset in childhood or adolescence and is frequently associated with parkinsonian features. Our patient had non-hereditary neck and trunk dystonia of late onset that responded to L-DOPA. Her disorder may constitute a specific form of dopa-responsive dystonia.

Age Factors↗
PubMed1990

The poliovirus receptor protein is produced both as membrane-bound and secreted forms.

Both genomic and complementary DNA clones encoding poliovirus receptors were isolated from genomic and complementary DNA libraries prepared from HeLa S3 cells, respectively. Nucleotide sequence analysis of these cloned DNAs revealed that the poliovirus receptor gene is approximately 20 kb long and contains seven introns in the coding region, and that at least four mRNA isoforms referring to the coding sequence are generated by alternative splicing and appear to encode four different molecules, that is, PVR alpha, PVR beta, PVR gamma and PVR delta. The predicted amino acid sequences indicate that PVR alpha and PVR delta, corresponding to the previously described cDNA clones H20A and H20B, respectively, are integral membrane proteins while the other two molecules described here for the first time lack a putative transmembrane domain. Mouse cell transformants carrying PVR alpha were permissive for poliovirus infection, but those carrying PVR beta were hardly permissive. In contrast to PVR alpha, PVR beta was not detected on the surface of the mouse cell transformants but was detected in the culture fluid by an immunological method using a monoclonal antibody against poliovirus receptor. Three types of splicing products for PVR alpha, PVR beta and PVR gamma were detected by polymerase chain reactions using appropriate primers in poly(A)+ RNAs of the brain, leukocyte, liver, lung and placenta of humans; the choice of primers used did not permit detection of PVR delta. In situ hybridization using a cDNA fragment as a probe demonstrated that the PVR gene is located at the band q13.1----13.2 of human chromosome 19.

Amino Acid Sequence↗
PubMed1990

Synthesis and localization of Japanese encephalitis virus RNAs in the infected cells.

Synthesis and localization of virus-specific RNA in cells infected with Japanese encephalitis virus (JEV) were examined. To prepare specific RNA probes, we constructed four kinds of plasmids which contained DNA fragments corresponding to JEV genomic RNA. Minus probes, JT18V and JT19III, transcribed by T7 RNA polymerase were able to recognize a negative strand of JEV-specific RNA synthesized in cells as early as 6 hr postinfection (p.i.). In the experiments using a plus-strand probe JT19V to hybridize the 3' end of JEV-RNA, not only full-length 42S(+) RNA but also 10S(+) RNA were detected in the infected cells at 24 hr p.i. The positive-strand 42S RNA was found in much greater abundance in the membrane fraction than in the supernatant fraction of the infected cells. In contrast, larger amounts of the negative-strand RNAs existed in the supernatant fraction. It is suggested from the data that the JEV-specific negative- and positive-strand RNAs accumulate at different sites in the infected cells.

Animals↗
PubMed1990

[A case report of an acute myelogenous leukemia (FAB M1) with Klinefelter's syndrome].

Reported is the second documented case in Japan of acute leukemia with Klinefelter's syndrome. The patient, a 52-year-old male, was admitted to hospital on July 9, 1983, after complaining of a fever and general malaise. The hematological examinations revealed a WBC count of 14,300/cmm with 32% being leukemic cells. Bone marrow aspiration disclosed a nucleated cell count of 687,000/cmm with 41.6% being leukemic cells consisting of myeloblasts. The endocrinic laboratory data showed a high level of urine gonadotropin and chromosomal studies revealed a 47,XXY karyotype. A diagnosis of acute myelogenous leukemia (M1) with Klinefelter's syndrome thus was derived from these findings.

Humans↗
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↗