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T Kurata

Publications and source records attributed to T Kurata.

At least 127 records · Page 7Linked to original sources
PubMed1998

Comparison of the ability of viral protein-expressing plasmid DNAs to protect against influenza.

The ability of plasmid DNA encoding various influenza viral proteins from the A/PR/8/34 (H1N1) virus to protect against influenza was compared in BALB/c mice. The plasmid DNA encoded hemagglutinin (HA), neuraminidase (NA), matrix protein (M1), nucleoprotein (NP) or nonstructural protein (NS1) in a chicken beta-actin-based expression vector (pCAGGS). Each DNA was inoculated twice 3 weeks apart at a dose of 1 microgram per mouse by particle-mediated DNA transfer to the epidermis (gene gun). Seven days after a second immunization, mice were challenged with the homologous virus and the ability of each DNA to protect mice from influenza was evaluated by decreased lung virus titers and increased survival. Mice, given HA- or NA-expressing DNA, induced a high level of specific antibody response and protected well against the challenge virus. On the other hand, mice given M1-, NP-, or NS1-DNA failed to provide protection, although M1- and NP-DNAs did induce detectable antibody responses. These results indicate that both HA- and NA-expressing DNAs for the surface glycoproteins are most protective against influenza from among the various viral protein-expressing DNAs used here.

Animals↗
PubMed1998

IgA antibody-forming cell responses in the nasal-associated lymphoid tissue of mice vaccinated by intranasal, intravenous and/or subcutaneous administration.

Effects of a single intranasal (i.n.), subcutaneous (s.c.) or intravenous (i.v.) vaccination and their combined vaccination of priming and boosting on a primary and a secondary IgA antibody forming cell (AFC) response were examined in the nasal associated lymphoid tissue (NALT), spleen and popliteal lymph nodes (pLNs) of BALB/c mice. Mice were primed with the vaccine prepared from A/Yamagata/120/86 (H1N1) together with a cholera toxin-adjuvant and boosted with the same vaccine 3 weeks later. Three days after boosting, IgA-AFC responses in each lymphoid tissue were measured as an index of the immunological memory that mediates a secondary IgA-AFC response. Single i.n. vaccination induced a greater primary IgA-AFC response in the NALT not only than that in the spleen or pLNs, but also than that induced by single i.v. or s.c. vaccination. The combination of i.n. priming and i.n. boosting afforded a greater anamnestic IgA-AFC response in the NALT not only than that in the spleen or pLNs, but also than that induced by any other combinations of priming and boosting (i.n.-i.v., i.n.-s.c., s.c.-i.n., s.c.-i.v., and s.c.-s.c.). These results showed that i.n. priming induced a greater primary IgA-AFC response in the NALT and simultaneously induced the immunological memory that mediated a greater secondary-type AFC response following i.n. boosting in the NALT.

Administration, Intranasal↗
PubMed1998

Constitutive association of EGF receptor with the CrkII-23 mutant that inhibits transformation of NRK cells by EGF and TGF-beta.

Crk belongs to the adapter proteins that participate in many signalling pathways from cell surface receptors. We have characterised the CrkII-23 mutant that inhibits the transformation of NRK cells induced by epidermal growth factor (EGF) and transforming growth factor (TGF)-beta. To study the biochemical difference, cDNAs of the wild-type CrkII and the CrkII-23 mutant were introduced stably into NIH 3T3 cells expressing EGF receptor (EGFR). Both CrkII and CrkII-23 were phosphorylated on tyrosine upon EGF simulation with similar time course and dose dependency. Whereas the wild-type CrkII bound to EGFR only after EGF stimulation, CrkII-23 bound to EGFR from before stimulation. Mutation in the Src homology (SH) 2 or amino-terminal SH3 domain did not abolish the binding of CrkII-23 to EGFR in the quiescent cells, suggesting that the binding is mediated by a novel mechanism. These CrkII-23-derived mutants, however, did not suppress transformation of NRK cells by EGF and TGF-beta. Hence, both the SH2 and amino-terminal SH3 domains are required to inhibit transformation of NRK cells. These results suggest that persistent signalling from CrkII-23 bound to EGFR suppresses transformation by EGF and TGF-beta in NRK23 cells.

3T3 Cells↗
PubMed1998

Induction of interleukin-10 on activation of Epstein-Barr virus in EBV-infected B-cell lines.

Human (h) interleukin-10 (IL-10) exhibits a strong DNA and amino acid sequence homology to the Epstein-Barr virus (EBV) BCRF1 genome, viral (v) IL-10. We analyzed the production of IL-10 for EBV activation in B-cell lines. The latent EBV in Akata cells was activated by the cross-linking of surface immunoglobulin G (IgG) with anti-human IgG. The levels of IL-10(h+v) and vIL-10 in the culture fluids were measured by a specific enzyme-linked immunosorbent assay (ELISA). IL-10(h+v) was detected at the same time for EBV immediate early gene BZLF1 product ZEBRA and early gene BMRF1 product EA-D. This was more than 4 hours prior to the appearance of vIL-10, and late gene products gp 350/220 and viral capsid antigen. The induction of hIL-10 and vIL-10 mRNAs were detected in anti-IgG-treated Akata cells by reverse transcription-polymerase chain reaction. The induction of IL-10(h+v) and vIL-10 was inhibited with a tyrosine kinase inhibitor, herbimycin, or with an inhibitor of herpesvirus DNA polymerase, phosphonoacetic acid, or acyclovir. IL-10(h+v) and vIL-10 were also detected in the supernatants of Akata and Daudi but not Ramos cells infected with P3HR-1 EBV. These results show the IL-10 induction on EBV activation in EBV-carrying B-cell lines.

Acyclovir↗
PubMed1998

Enhancement of human immunodeficiency virus type 1 infectivity by Nef is producer cell-dependent.

The growth kinetics of wild-type and nef mutant viruses of human immunodeficiency virus type 1 were comparatively analysed in several human CD4+ cell lines. Delayed replication of nef mutant virus was observed in all cell lines examined. To determine the stage in the virus replication cycle that is affected by Nef, a single-round replication assay was performed. Initially, the expression of marker genes in transfected cells was examined in order to study the role of Nef in the late phase of infection. The results obtained indicated that Nef is dispensable during the transcription to virion production stage. Next, the effect of Nef on the early phase was investigated with a single-round infection. It was demonstrated that Nef is required in the early phase of the virus replication cycle, from virion adsorption to integration. Finally, the infectivity of virus stocks prepared from four cell lines was determined. The relative infectivity of the nef mutant from the four cell lines differed. Taken together, we conclude that Nef acts via modulation of viral particles to enhance virus infectivity in a cell-dependent manner.

Gene Products, nef↗
PubMed1998

Binding of human cytomegalovirus to sulfated glucuronyl glycosphingolipids and their inhibitory effects on the infection.

Interactions between human cytomegalovirus (HCMV) and various carbohydrate structures were analysed using sulfated glucuronyl glycosphingolipids (SGGLs) and the structurally related glycosphingolipids (GLs). A thin-layer chromatography-overlay assay and a solid-phase binding assay revealed that HCMV strongly bound to sulfated glucuronyl lactosaminylparagloboside, one of the SGGLs having the repeating lactosamine structure (3Gal beta1-4GlcNAc1-)2 in addition to the 3-O-sulfated glucuronyl moiety. The virus bound less strongly to other 3-O-sulfated GLs, which included sulfated glucuronyl paragloboside and cerebroside sulfate ester, and also to (3Gal beta1-4GlcNAc1-)2-containing GLs that included nLc6Cer. Thus, a (3Gal beta1-4GlcNAc1-)2 and a 3-O-sulfated saccharide seem to be important structures for the binding by HCMV. When virus particles were preincubated with these GLs, inhibitory effects were observed both on expression of the viral immediate-early gene and on plaque formation by HCMV. These effects were very well correlated with the abilities of the GLs to bind to the virus. Pretreatment of host cells with HNK-1 monoclonal antibody, which specifically recognizes SGGLs, resulted in partial inhibition of plaque formation by HCMV. These results clearly show that HCMV recognizes and binds to the sulfated carbohydrate structure in SGGL and also suggest that binding of HCMV to the specific sugar structure may play an important role in HCMV infection.

Animals↗
PubMed1998

Antibody-forming cells in the nasal-associated lymphoid tissue during primary influenza virus infection.

Antibody-forming cell (AFC) responses in the nasal-associated lymphoid tissue (NALT) of BALB/c mice were examined following intranasal infection, mainly of the upper respiratory tract, with a small volume of influenza virus. The infection induced significant accumulation of T and B cells in NALT, peaking around day 7 post-infection. Virus-specific IgA, IgG and IgM AFC responses were induced, developing from day 5 and peaking at day 7; responses were predominantly IgA and IgG, followed by IgM. At peak, NALT contained the greatest number of IgA AFCs per total cells of the lymphoid tissues examined in the upper respiratory tract. The IgM AFC responses were induced in NALT cell cultures from uninfected mice following in vitro culture with influenza virus, indicating that at least a part of the AFCs in infected mice may have originated from specific B cell precursors in NALT. In parallel with the detection of AFCs in infected mice, virus-specific IgA antibodies appeared in the nasal wash and their appearance correlated well with virus clearance from the nasal area. These results suggest that virus-specific IgA antibodies, produced by IgA AFCs in NALT, play an important role in recovery from infection.

Animals↗
PubMed1998

The BglII-N fragment of herpes simplex virus type 2 contains a region responsible for resistance to antiviral effects of interferon.

Double infection with two interferon (IFN)-sensitive strains of herpes simplex virus (HSV), HSV-1(17syn) and HSV-2(UW268), showed reduced inhibition of virus growth by IFN. Intertypic recombinants with IFN resistance were obtained from the doubly infected cultures. These results indicate that HSV IFN resistance is controlled by at least two genetic regions. Restriction endonuclease analysis demonstrated that the recombinants were similar to HSV-2 in their genomic structure but the BamHI-A, BglII-I and BglII-N fragments of HSV-2 were commonly lost in the recombinants, suggesting that any of these fragments could be associated with HSV-2 IFN resistance. We cloned these fragments and BamHI-E, which overlaps BglII-N, from an IFN-resistant HSV-2 strain, HSV-2(G), and examined each fragment for its ability to rescue IFN resistance of HSV-2(UW268) by co-transfecting with the HSV-2(UW268) genome. Of the HSV-2(G) fragments, only BglII-N increased plating efficiency of progeny viruses in IFN-treated cells. An IFN-resistant HSV-2 clone was obtained from the BglII-N of HSV-2(G) and HSV-2(UW268) genome co-transfected culture, and a part of BglII-N of HSV-2(UW268) was replaced with that of HSV-2(G) in the HSV-2 clone. Thus, it was concluded that one of the HSV regions encoding IFN resistance is located on the BglII-N fragment of HSV-2.

Animals↗
PubMed1998

petit1, a conditional growth mutant of Arabidopsis defective in sucrose-dependent elongation growth.

The hypocotyl of Arabidopsis is well suited for the analysis of cell elongation because it elongates without cell division. We have isolated a new class of recessive mutants, petit1 (pet1), which are defective in aspects of hypocotyl elongation. The short-hypocotyl phenotype of pet1 is caused by shortened cells. The cells of the elongation zone of the hypocotyl are often deformed. pet1 also shows defects in elongation of the roots, flower stalk, leaves, petals, pedicels, and siliques, and these defects cannot be repaired by the application of auxin, gibberellin, brassinolide, or an inhibitor of ethylene biosynthesis. The short-hypocotyl phenotype of pet1 is pronounced only in growth medium supplemented with sucrose, which has promotive effects on hypocotyl elongation. In pet1 this effect is much reduced, causing the sucrose-dependent short-hypocotyl phenotype of pet1. pet1 accumulates more soluble sugars than the wild type and also shows more intensive iodo-starch staining in the cotyledon and hypocotyl. These results indicate that PETIT1 is involved in a sugar-dependent elongation process that may include correct assembly of expanding cell wall architecture.

Arabidopsis↗
PubMed1998

Pretreatment with restriction enzyme or bovine serum albumin for effective PCR amplification of Epstein-Barr virus DNA in DNA extracted from paraffin-embedded gastric carcinoma tissue.

An association between Epstein-Barr virus (EBV) and gastric carcinoma has been studied through the EBV genome present in the carcinoma cells. Recently, we found that EBV DNA in paraffin-embedded gastric carcinoma tissue was detected effectively by PCR after pretreatment of the extracted DNA with a restriction enzyme, BamHI or EcoRI. Here, we show that the PCR amplification was also enhanced by pretreatment of the DNA with other restriction enzymes or with bovine serum albumin and several other proteins. Treatment with these proteins may remove a PCR inhibitor(s) in the DNA samples extracted from the paraffin blocks.

Animals↗
PubMed1998

Inhibition of human immunodeficiency virus type 1 virion entry by dominant-negative Hck.

To study the role of Src family tyrosine kinases in infection with human immunodeficiency virus type 1 (HIV-1), we constructed an Hck mutant, HckN, that hinders signaling from wild-type Hck. HIV-1 produced in HckN-expressing cells was significantly less infectious to HeLa-CD4-LTR-beta-gal (MAGI) cells than HIV-1 produced in mock-transfected cells. The inhibitory effect of HckN was compensated for by the expression of vesicular stomatitis virus G protein. Finally, we found that the HIV-1 produced in the HckN-expressing cells entered into the cells less efficiently than did the control HIV-1. These results suggest that the Src family tyrosine kinases regulate entry of HIV-1 into target cells.

Gene Products, nef↗
PubMed1998

Evaluation of antibodies to the Epstein-Barr virus immediate early gene product ZEBRA by a new enzyme-linked immunosorbent assay.

For the serodiagnosis of Epstein-Barr virus (EBV) infections, we have developed a new enzyme-linked immunosorbent assay (ELISA) for antibodies to the ZEBRA product of EBV immediate early gene BZLF1. ZEBRA protein fused with glutathione-S-transferase (GST) was expressed in Escherichia coli and purified by affinity chromatography with glutathione-Sepharose 4B. An ELISA sandwich capture system was constructed with the GST-ZEBRA immobilized on plastic microtiter plates which had been coated with a mouse monoclonal antibody to GST. ZEBRA-IgG antibodies in patients' sera with chronic active EBV infection (CAEBV) and infectious mononucleosis (IM) had, respectively, very high and high titers. Anti-ZEBRA antibodies were also detected at low titers in sera of some healthy controls. ZEBRA-IgM antibodies were detected in sera of patients with IM and CAEBV but not in sera of healthy controls. In sera of patients with CAEBV, the titers of IgG antibodies to ZEBRA correlated with the antibody titers to early antigens obtained with an immunofluorescence assay, but not to EBV nuclear antigens. This ELISA is a useful diagnostic and prognostic test for EBV infection.

Adolescent↗
PubMed1998

Physiological role of L-ascorbic acid in rats exposed x887p6arette smoke.

This study clarifies the effect of exposure to cigarette smoke on L-ascorbic acid (AsA) metabolism and on the activities of drug-metabolizing enzymes. Male Wistar rats were used. The test rats (group T) were exposed to side-stream smoke from cigarette for 2 h every day for 25 days. During the experimental period, the excreted amount of AsA in the urine from group T was higher than that from the control group (group C). At the end of the experimental period, the AsA content of the plasma and tissues, the liver cytochrome P-450 content and the activities of drug-metabolizing enzymes in group T were each higher than those in group C.

Animals↗
PubMed1998

Contents of erythorbic acid in the tissues of guinea pigs intraperitoneally administered erythorbic acid.

The contents of ascorbic acid (AsA) and erythrobic acid (ErA) in the tissues of guinea pigs intraperitoneally injected with AsA and/or ErA were determined to learn the difference in their retention in the tissues. After 10 d of AsA depletion, the guinea pigs were intraperitoneally injected with 5 mg of AsA, or 5 mg of ErA, or 5 mg of each. At day 5 of repletion, the guinea pigs were killed and liver, adrenal glands, spleen, and kidneys were removed. AsA and ErA in these tissues were measured by using HPLC. The contents of AsA in the tissues of only the AsA-injected guinea pigs were similar to those of the AsA- + ErA-injected guinea pigs. The contents of ErA in the tissues of the ErA-injected guinea pigs were higher than those of the AsA- + ErA-injected guinea pigs, but apparently lower than the contents of AsA in the AsA-injected guinea pigs. ErA was scarcely retained in the tissues of guinea pigs.

Adrenal Glands↗
PubMed1998

[Pathology of human cytomegalovirus infection in immunocompromised hosts].

We reviewed the histopathological diagnosis of human cytomegalovirus (HCMV) and the pathology of HCMV infection in immunocompromised hosts. For histological diagnosis, routine staining of paraffin sections of formalin fixed tissue obtained at biopsy and autopsy is important to detect cytomegalic inclusion (owl's eye). For confirmation of HCMV diagnosis, immunohistological detection of immediate early and structural proteins of HCMV is valuable. Cytomegalic inclusion contains a Cowdry A inclusion consisting nucleocapsid and electron dense networks in the nucleus and sometime many dense bodies in the cytoplasm. In situ hybridization for viral transcripts and genome and immunohistological detection of immediate early proteins occasionally reveal HCMV-infected cells not showing cytomegalic inclusion. HCMV infections in immunocompromised hosts are not always associated with apparent clinical manifestations. Among these infections, gastrointestinal and retinal infections are frequently associated with serious outcomes.

Biomarkers↗
PubMed1998

Modulation of select immune responses by dietary capsaicin.

Capsaicin (CAP) is the spicy principle of hot peppers that has been used as a food additive, preservative, and medicine. In this study, we investigated the effect of dietary CAP on immune status and selected immune responses. BALB/c mice were divided into 5 groups and fed diets with either 0, 5, 20, 50 or 100 ppm CAP for 3 weeks. The parameters measured with lymphocytes included mitogen-induced proliferation, plaque-forming cell number, and total serum immunoglobulin levels. In spleen cells of mice fed 20 ppm CAP there was a greater T-cell mitogen induced, lymphocyte proliferative response. In addition, the number of antibody-producing B cells and serum IgG and IgM levels increased in mice fed 20 ppm CAP as compared to the control with no CAP. The effect of dietary CAP on macrophage activity was assessed by phagocytosis and tumor necrosis factor-alpha (TNF alpha) production. Dietary CAP had no effect on phagocytic activity by peritoneal macrophages, but the levels of secreted TNF alpha increased in the groups fed 20 ppm CAP compared to the control. These results suggest that dietary CAP may differentially enhance immune status as well as select immune functions. That is in contrast with previous studies that show immunosuppression observed after CAP injection.

Animals↗
PubMed1998

Amino-reductones. Formation mechanisms and structural characteristics.

Various types of amino-reductones are known to be involved in process-induced chemical changes in foods. Since most amino-reductones, especially enaminol compounds are unstable reaction intermediates and are difficult to isolate, their structural characteristics are still unclear. In order to obtain more precise structural information about amino-reductones, the structures of the enaminol form of fructoseglysine (D-fructoseglycine = FG) and scorbamic acid (L-scorbamic acid = SCA), a relatively stable cyclic enaminol compound were examined by the use of a semi-empirical molecular orbital method. Optimized structures, heat of formations and charge distributions of various enol forms of FG were obtained. Heat of formations of the non-dissociated, mono-anion, and di-anion forms of FG were estimated to be about -302, -347 and -308 kcal/mol, respectively. Optimized structures of non-dissociated, anion, and dipolar ion forms of SCA were also obtained and their heat of formations were estimated to be about -197, -204 and -248 kcal/mol, respectively. The nitrogen atom of the enaminol group in the SCA molecule was found to be positively charged.

Ascorbic Acid↗