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Biomedical subjects

I Nagata

Publications and source records attributed to I Nagata.

At least 343 records · Page 19Linked to original sources
PubMed1978

Anti-thyroxine and anti-triiodothyronine antibodies in three cases of Hashimotos thyroiditis.

Antibodies against thyroxine (T4) and/or triiodothyronine (T3) were detected in 3 patients with Hashimoto's thyroiditis. One of the patients had both anti-T4 and anti-T3 antibodies and the other 2 patients had only anti-T3 antibody. Serum T4 or T3 antibodies and the other 2 patients had only anti-T3 antibody. Serum T4 or T3 values measured by the single antibody radioimmunoassay (RIA), were low or nil in these patients. One patient was mildly hypothyroid. The other 2 patients were clinically euthyroid, but they were considered latent hypothyroid because of a slight elevation in serum TSH. On extraction of the sera with ethanol, high or normal values of T3 were obtained in all cases. Recovery of T4 or T3 added to the patients' sera determined by RIA was significantly low. The binding of [125I]T4 or [125I]T3 to the patients' sera was demonstrated by the polyethylene glycol method and by using RIA kits without adding the antibody provided. The binding activity was localized in the IgG fraction by column chromatography and by immunoprecipitation. T4- or T3-binding protein in two sera migrated in the gammaglobulin region on paper electrophoresis and was found in 7S fraction on Sephadex G-200 chromatography. In one serum containing both anti-T4 and anti-T3 antibodies, the association constants (Ka) for binding of T4 and T3 were 3.8 x 10(8) l/mol and 1.7 x 10(8) l/mol, respectively. The binding capacities in the serum were 8.2 microgram of T4 and 1.9 microgram of T3 per 100 ml of serum. For two sera containing anti-T3 antibody, Ka were 5.5 x 10(8) l/mol and 7.4 x 10(10) l/mol, and the binding capacities were 0.6 microgram/100 ml serum and 0.7 microgram/100 ml serum respectively. The clinical significance of these antibodies is discussed.

Adult↗
PubMed1978

Suprasellar germinoma.

The clinical features of 18 cases of suprasellar germinoma were reviewed, and the following points stressed: 1) The incidence of intracranial germinoma and teratoma seems to be much higher in Japan than elsewhere. 2) Germinomas in the pineal region, the third ventricle, and the lateral ventricle were observed to be predominant in males. In suprasellar germinoma, however, males were not affected predominantly and the male:female ratio was 1:1. 3) Suprasellar germinomas caused three symptoms: diabetes insipidus, visual disturbances, and pituitary dysfunctions. 4) Pituitary functions were disturbed to various degrees. Some cases showed hypopituitarism but some showed an elevation of plasma concentrations of cortisol or luteinizing hormone and follicle stimulating hormone. 5) Some abnormalities showing a suprasellar mass were usually found on neuroradiological examination. 6) Suprasellar germinomas were very sensitive to radiotherapy and some of them rapidly disappeared on follow-up computerized tomography scanning after irradiation with as little as 1200 rads.

Adolescent↗
PubMed1977

Comparative studies on cytopathic effects induced by vesicular stomatitis virus in two cell types.

Infection of mouse L cells with vesicular stomatitis virus (VSV) leads to an extensive cell fusion, while porcine kidney stable (PS) cells infected with VSV show only cell rounding. Therefore, comparative morphological studies on the infection of the two cell lines were carried out using a transmission or scanning electron microscope and an immunofluorescence microscope. PS cells infected with VSV contrasted to L cells infected with the same virus in the following two points; (1) the principal site of VSV maturation was the intracytoplasmic vacuolar membrane in PS cells and the plasma membrane in L cells. However, it was found that viral glycoprotein was present on the cell surface of infected PS cells; (2) the morphological changes at the cell surface of infected PS cells occurred much earlier and were severer than those at the cell surface of infected L cells. From these observations, we discuss the possibility that the surfaceembrane of PS cells is too sensitive to the VSV-induced cell damage to cause cell fusion.

Animals↗
PubMed1977

Affinity of Sendai virus for the inner ear of mice.

The direct immunofluorescent antibody method revealed that Sendai virus, which was thought to be most prevalent in respiratory diseases in mice, infected the inner ear of mice when the virus was injected intracerebrally. Specific immunofluorescence that indicated the presence of antigens of Sendai virus was observed in both perilymphatic and endolymphatic structures. The routes of virus spread are discussed. This experimental study, using newborn mice and Sendai virus, may be useful for the investigation of the pathogenesis of viral labyrinthitis not only because of the high frequency of inner ear infection, but also because of long-time survivors which facilitate prolonged observation.

Animals↗
PubMed1976

Surface antigens on HeLa cells persistently infected with HVJ (Sendai virus).

Surface antigens of HeLaHVJ cells, a cell line persistently infected with HVJ, were studied by fluorescent antibody staining. After absorption with concentrated HVJ virions and HeLa cells, anti-HeLaHVJ antiserum was able to demonstrate specific surface fluorescence on HeLaHVJ cells, while this serum no longer reacted with original HeLa cells nor with HVJ virions. During cytolytic infection of HeLa cells with HVJ, this specific surface antigen appeared at an early stage of infection prior to the appearance of newly synthesized HVJ viral antigens and moreover appeared in spite of the inhibition of viral protein synthesis. This antigen was detected neither on HeLa cells infected with other myxoviruses except HVJ nor on various other kinds of cells infected with HVJ. The specific surface antigen was still found on the HeLaHVJ cell surface after incubation at 38 degrees C for two days, while HVJ structural antigens on the cell surface no longer could be detected. Mild short-term treatment of HeLa cells with trypsin, neuraminidase from vibrio cholerae, phospholipase-C and hyaluronidase failed to expose specific antigen. The antigen was distinguishable from the Forssman and human blood type antigens. The mechanism of appearance of a new antigen on the surface of HeLaHVJ cells remains unclear.

Antigens↗
PubMed1976

Relationship between establishment of persistent infection of haemagglutinating virus of Japan and the properties of the virus.

The infectious virus (HVJ-pi) obtained from BHK cells persistently infected with haemagglutinating virus of Japan was found to be temperature-sensitive as well as causing little or no cytopathic effect (c.p.e.) and leading to establishment of carrier cultures in several cell lines at both permissive (32 degrees C) and non-permissive (38 degrees C) temperature. In order to obtain information about the role of HVJ-pi in the establishment of persistent infection, comparative studies were made of some phenotypic properties of HVJ-pi and HVJ-38 which was obtained by passing wild-type HVJ in eggs at 38 degrees C and was proved to be highly cytopathic. HVJ-pi differed from HVJ-38 in (1) temperature sensitivity in its ability to produce virus progeny, (2) infectivity for embryonated eggs, (3) neuraminidase activity, (4) the thermal stability of HA and neuraminidase activity, and (5) the polypeptide composition of BHK-grown viruses. B cells infected with HVJ-pi release haemagglutinin more efficiently, and less HA was accumulated on the cell membrane. In considering these results, it was concluded that the difference of envelope proteins might be involved in the striking difference in c.p.e. between HJV-pi and HVJ-38.

Cell Line↗
PubMed1976

Polykaryocyte formation induced by VSV in mouse L cells.

Infection of mouse L cells with VSV leads to the formation of polykaryocytes about 4 to 12 h p.i. When anti-VSV immune serum was added during the course of infection, progression of cell fusion was soon suppressed. Cycloheximide completely suppressed the cell fusion when the drug was added within 1 h p.i., while the cell fusion was not suppressed at all when the drug was added at and after 3 h. Early polykaryocyte formation, 'fusion from without', was observed only at a low level in cells infected at very high multiplicities. The development of cell fusion induced by VSV was found to be different in several cell types, although all these cells produced a rather high yield of virus: L and C-243-3 mouse cell lines showed a high level of polykaryocytosis (80 to 100%), BHK and RK-13 cells responded at low level, and PS and Vero cells showed no cell fusion in response to VSV infection. In PS cells, however, cell fusion occurred when VSV-infected L cells were co-cultivated. From these observations, the mechanism of cell fusion induced by VSV was discussed.

Animals↗
PubMed1976

The effects of cytochalasin and colchicine on interferon production.

The present study was undertaken to investigate the mechanism of interferon production by mouse spleen cells co-cultivated with BHK-HVJ cells, i.e. baby hamster kidney cells persistently infected with the HVJ (or Sendai) strain of para-influenza I virus. Cytochalasin B appears to inhibit an early stage in the process and colchicine a relatively late stage. It is suggested that microfilaments and microtubules may play in important role at an initial stage of interferon production in this system.

Animals↗
PubMed1976

Homologous interference induced by a temperature-sensitive mutant derived from an HVJ (Sendai virus) carrier culture.

Homologous interference between a temperature-sensitive small plaque mutant (HVJ-pB) derived from an HVJ (haemagglutinating virus of Japan - the Sendai strain of parainfluenza I virus) carrier culture of BHK cells and the original wild-type virus (HVJ-W) has been investigated. Prior infection of LLCMK2, HeLa, BHK or mouse L cells with HVJ-pB, both at permissive and non-permissive temperatures, for 24 h resulted in a reduced yield of superinfecting HVJ-W, reflecting a smaller number of cells capable of producing the superinfecting virus. However, HVJ-pB did not interfere with the replication of vesicular stomatitis virus, Sindbis virus or Newcastle disease virus. Interference in this system seems to be due to inhibition of the attachment of superinfecting HVJ-W as a result of intracellular mechanisms operating at a late stage in the replication of the interfering virus. There is also blocking or destruction of cellular receptors by extra-cellular particles of the interfering virus. Protein synthesis coded for by the complete virus genome is required to establish and maintain the interference, and treatment with actinomycin D has no effect on the interference phenomenon.

Adsorption↗
PubMed1976

Interferon-producing capacity of germfree mice.

The general capacity of germfree mouse spleen cells to produce interferon in vitro in response to various stimuli was investigated. The interferon response of germfree mouse spleen cells in vitro, when compared with that of the conventionals, appears to be lower to some inducers. Interferon production in vitro stimulated by hemagglutinating virus of Japan (HVJ) or BHK-HVJ cells (BHK cells persistently infected with HVJ) was apparently suppressed in germfree mouse spleen cells as compared with the corresponding conventionals, whereas no difference of interferon production was observed between germfree and conventional mouse spleen cells in response to Newcastle disease virus, Escherichia coli endotoxin, poly(I:C), and phytohemagglutinin. Although monocontamination with HVJ had no enhancing effect on the interferon-producing ability of germfree mouse spleen cells in response to HVJ, conventionalization for 2 weeks greatly enhanced interferon-producing capacity.

Animals↗
PubMed1976

Pathogenesis of Sendai virus infection in the central nervous system of mice.

The present study was aimed to clarify the pathogenesis of Sendai virus infection to the central nervous system (CNS) of mice. One-to 2-day-old suckling and 4-week-old mice were inoculated intracerebrally with the virus. The virus multiplied higher in suclings than in adults. Immunofluorescent studies in sucklings revealed that the viral antigens appeared initially in ependyma, choroid plexus epithelium, and meninges. Subsequently they spread to subependymal cells and finally were found in neurons of hippocampus for as long as 4 months postinfection. In adults, however, the viral antigens rapidly disappeared in the early stage. Most mice inoculated intracerebrally with Sendai virus appeared healthy, although hydropcephalus developed in a few mice. Virus-specific antibody and interferon production seemed to have no influence on the persistent infection of Sendai virus in the CNS of mice. One of the most significant findings may be that the viral antigens persist in the brain for as long as 4 months in a latent form. This may offer a useful model for the study of latent CNS infection of paramyxoviruses.

Aging↗
PubMed1976

Effects of thyroxine on T-cell counts and tumour cell rejection in mice.

In an attempt to study the effect of thyroxine on peripheral T-cell (thymus derived lymphocyte) counts or immunological functions, inbred C3H/He mice (8-10 weeks old) were injected subcutaneously with thyroxine for more than 3 months. After treatment for 3 months the mice were examined for peripheral T-cell counts, thymic incorporation of tritiated thymidine and rejection of tumour transplants. The number of T-cells was counted by the indirect immunoflourescence method using anti-thetaC3H serum after separation of lymphocytes on "Ficoll-Conray". It was revealed that the peripheral counts of both lymphocytes and T-cells were increased in the thyroxine treated group as compared with the control group, as was reported in the patients with Graves' disease. Thymic incorporation of tritiated thymidine was also found to be significantly increased in the thyroxine treated group. In addition, in order to study T-cell activity of the host, thyroxine treated and control mice were challenged with Ehrlich carcinoma cells at several concentrations (10(2), 10(4) and 2 x 10(6) per mouse). It was found that rejection of tumour transplants was significantly enhanced in the T-cell rich mice. Thus, it is possible that throxine affects peripheral T-cell counts and enhances immunological functions of the host.

Animals↗
PubMed1975

Development of mitochondrial membranes in anaerobically grown yeast cells.

Biochemical analyses of mitochondrial marker substances, especially cardiolipin and oligomycin-sensitive ATPase [EC 3.6.1.3], as well as electron microscopic observations were carried out to eludicate the process of mitochondrial development in annaerobic yeast cells. Cardiolipin was found to be localized in the mitochondria in anaerobic cells. Its cellular content was a little higher in the stationary phase than in the exponential phase in glucose-grown cells and increased further in galactose-grown cells. The lipid content of the mitochondrial preparation obtained from glucose-grown stationary cells was nearly as high as that from galactose-grown cells. It was also comparable to that of aerobic cells in the stationary phase, where mitochondria are fully developed. Both cellular and mitochondrial levels of oligomycin-sensitive ATPase activity were also found to rise markedly in galactose-grown anaerobic cells, although not in stationary phase cells grown anaerobically on glucose. These high levels of the mitochondrial markers indicate a developmental change in mitochondrial structure even in anaerobically grown cells, which lack mitochondrial cytochromes. In the process of aerobic adaptation, respiratory system formation was observed to occur much faster in galactose-grown cells than in glucose-grown cells, and not to be inhibited by chloramphenicol and high concentrations of glucose structure in anaerobic cells. The developmental change was also corroborated by electron microscopic observations, which revealed the occurrence of two types of mitochondria in anaerobic cells. One was found in glucose-repressed cells and was characterized by the presence of numerous electron-dense granules in the matrix. In contrast, the other type, found in glucose-derepressed cells, had an electron-lucent matrix. No crista membrane was seen in either type of mitochondria in anaerobic cells, although the infoldings of the inner membrane, which partition the matrix into two parts and therefore are called "septum membranes," appeared frequently in the stationary phase cells. On the basis of these results, the process of mitochondrial development in yeast cells is discussed.

Adenosine Triphosphatases↗
PubMed1975

Iterferon induction in mice by BHK cells persistently infected with HVJ.

Intraperitoneal injection into mice of BHK-HVJ cells (BHK cells persistently infected with HVJ) induced considerable amounts of circulating interferon. Sonication of BHK-HVJ cells almost totally abolished their interferon inducing capacities. This result suggests that a certain native organized structure of virus infected cells might be essential for production of interferon in this system, as is suggested in the in vitro sytem.

Animals↗