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N Fujii

Publications and source records attributed to N Fujii.

At least 163 records · Page 9Linked to original sources
PubMed1998

Poor induction of interferon-induced 2',5'-oligoadenylate synthetase (2-5 AS) in cells persistently infected with mumps virus is caused by decrease of STAT-1 alpha.

Poor induction of interferon-induced 2',5'-oligoadenylate synthetase (2-5AS) has been demonstrated in cells persistently infected with mumps virus as compared with uninfected cells. As for the number of interferon (IFN) receptors and the level of IFN regulatory factors (IRF-1 and IRF-2) mRNAs, there was little difference between them. Therefore, it is suggested that the IFN-alpha signaling system is ineffective in the persistently infected cells. Components of IFN-stimulating gene factor 3 alpha (ISGF-3 alpha), STAT-1 alpha (p91) and STAT-2 (p113), were investigated in human amnion (FL), human nasopharyngeal cancer (KB), human T-lymphoid (HUT 78), and human B-lymphoid (Akata) cells persistently infected with mumps virus. STAT-1 alpha, but not STAT-2, disappeared in these persistently infected cells, and this factor was not restored by treatment of these cells with IFN. However, no difference was observed between the levels of STAT-1 alpha mRNA transcript in persistently infected and uninfected control cells. It is reasonable to infer that the poor induction of 2-5AS activity is due to the decrease of STAT-1 alpha in correlation with the IFN-signal transduction pathway. Furthermore, induction of other IFN-stimulated genes (ds-RNA activated protein kinase, PKR, and MxA protein) was also reduced in the cells persistently infected with mumps virus.

2',5'-Oligoadenylate Synthetase↗
PubMed1998

Advanced glycation end products in Alzheimer's disease and other neurodegenerative diseases.

Advanced glycation end products (AGEs) have been implicated in the chronic complications of diabetes mellitus and have been reported to play an important role in the pathogenesis of Alzheimer's disease. In this study, we examined the immunohistochemical localization of AGEs, amyloid beta protein (A beta), apolipoprotein E (ApoE), and tau protein in senile plaques, neurofibrillary tangles (NFTs), and cerebral amyloid angiopathy (CAA) in Alzheimer's disease and other neurodegenerative diseases (progressive supranuclear palsy, Pick's disease, and Guamanian amyotrophic lateral sclerosis/Parkinsonism-dementia complex). In most senile plaques (including diffuse plaques) and CAA from Alzheimer's brains, AGE and ApoE were observed together. However, approximately 5% of plaques were AGE positive but A beta negative, and the vessels without CAA often showed AGE immunoreactivity. In Alzheimer's disease, AGEs were mainly present in intracellular NFTs, whereas ApoE was mainly present in extracellular NFTs. Pick's bodies in Pick's disease and granulovacuolar degeneration in various neurodegenerative diseases were also AGE positive. In non-Alzheimer neurodegenerative diseases, senile plaques and NFTs showed similar findings to those in Alzheimer's disease. These results suggest that AGE may contribute to eventual neuronal dysfunction and death as an important factor in the progression of various neurodegenerative diseases, including Alzheimer's disease.

Adult↗
PubMed1998

Overlapping epitopes of friend murine leukemia virus gag-encoded leader sequence recognized by single cytotoxic T-lymphocyte clones.

The leader signal sequence of the non-structural gag-encoded glycoprotein precursor, Pr75gag, of Friend murine leukemia virus (F-MuLV) contains overlapping epitopes, SIVLCCLCL (p71-79) and CCLCLTVFL (p75 83) that activate Friend virus (FV)-induced tumor (FBL-3)-specific cytotoxic T-lymphocytes (CTL) (Kondo et al., J. Virol., 69, 1995, 6735-6741; Chen et al., J. Virol., 70, 1996, 7773-7782). It was investigated whether these two peptides are recognized by a single CTL clone or by individual clones with different specificities. The results show that both hydrophobic and cysteine-containing peptides are bound to H-2Db class I major histocompatibility complex (MHC) molecules and cross-recognized by a single CTL clone as well as bulk-cultured CTL from the spleens of mice immunized with FBL-3. The peptide p71-79 was effective for sensitizing target cells to lysis by CTL in the concentration of common antigenic peptides. Moreover, peptide p75-83 was 1000-fold more potent than the peptide p71-79. Specific cytotoxicity assays with variant peptides with alanine- and serine-substitutions suggested a highly complex function of the disulfide bond-forming peptides potentially sensitive to small sequence differences. The dominance of CTL responses to the transmembrane region is discussed in light of the high affinity of a novel hydrophobic peptide to compete with other peptides for binding to MHC molecules.

Amino Acid Sequence↗
PubMed1998

Cloning and sequencing of BeS-1 gene encoding the immunogenic antigen of Streptococcus sanguis KTH-1 isolated from the patients with Behçet's disease.

In order to analyze the immunopathologic mechanisms of Behçet's disease, the gene (bes-1) encoding a streptococcal antigen correlated with the disease was cloned and sequenced, and protein produced by this clone was identified by Western immunoblotting using serum antibody from the patient. Cellular DNA of Streptococcus (S.) sanguis serotype KTH-1 (uncommon serotype 1, strain 113-20) from the patient was extracted and digested with EcoRI. The digested fragments were cloned into the cloning vector lambda gt11, and then the resulting DNA library was immunoscreened using the patient's serum antibody to serotype KTH-1. The immunopositive clone of the 1.5 kbp fragment was subcloned into pUC 118 plasmid (pU8BeS1-1) and sequenced. The sequence showed that the 3'-terminal half side region of this insert contained 962bp of open-reading frame (ORF) discontinued at the EcoRI restriction site, and the stop codon was not found. The nucleotide sequence of the remaining additional 3'-terminal region of this gene encoding whole BES-1 was determined by genome walking. The whole ORF of bes-1 consisted of 849 amino acid residues with a calculated molecular mass of 95 kDa. The residues in a portion of the amino acid sequence showed a 60% correspondence to those of the human intraocular peptide Brn-3b.

Amino Acid Sequence↗
PubMed1998

Effective lowly cytotoxic analogs of an HIV-cell fusion inhibitor, T22 ([Tyr5,12, Lys7]-polyphemusin II).

A tachyplesin peptide analog, T22 ([Tyr5,12, Lys7]-polyphemusin II), and its shortened congener, TW70 (des-[Cys8,13, Tyr9,12]-[D-Lys10, Pro11]-T22) have strong anti-human immunodeficiency virus (HIV) activity, comparable to that of 3'-azido-2', 3'-dideoxythymidine (AZT). T22 and TW70 are extremely basic peptides, containing 5 Arg residues and 3 Lys residues. The number of positive charges might be related in part to high collateral cytotoxicities of T22 and TW70. Here we have synthesized several analogs, in which the number of positive charges has been reduced through amino acid substitutions using Glu or L-citrulline. As a result, several effective compounds have been found which possess higher selectivity indexes (SIs, 50% cytotoxic concentration/50% effective concentration) than those of T22 and TW70. Higher SIs were attributed mainly to a decrease in cytotoxicity.

Amino Acid Sequence↗
PubMed1998

Downsizing of an HIV-cell fusion inhibitor, T22 ([Tyr5,12, Lys7]-polyphemusin II), with the maintenance of anti-HIV activity and solution structure.

T22 ([Tyr5,12,Lys7]-polyphemusin II) has been shown to have strong anti-human immunodeficiency virus (HIV) activity comparable to that of 3'-azido-2',3'-dideoxythymidine (AZT). T22, an 18-residue peptide amide, takes an antiparallel beta-sheet structure that is maintained by two disulfide bridges. Herein we synthesized several shortened analogs of T22 in order to search for a more suitable lead compound. A 14-residue analog having one disulfide bridge, TW70 (des-[Cys8,13, Tyr9,12]-[D-Lys10, Pro11]-T22), was found to have highly potent activity comparable to that of T22, and to take an antiparallel beta-sheet structure similar to that of T22. This indicates that the molecular size of T22 can be reduced without loss of activity or significant change in the secondary structure, and that TW70 may represent a novel lead compound. Furthermore, modifying the N-terminal alpha-amino group of TW70 with a fluoresceinthiocarbamoyl group, and the epsilon-amino group of D-Lys8 at the turn portion with a 5-aminopentanoyl group remarkably increased the selectivity index (50% cytotoxic concentration/50% effective concentration).

Amino Acid Sequence↗
PubMed1998

Pharmacophore identification of a chemokine receptor (CXCR4) antagonist, T22 ([Tyr(5,12),Lys7]-polyphemusin II), which specifically blocks T cell-line-tropic HIV-1 infection.

We have previously found that T22 ([Tyr(5,12), Lys7]-polyphemusin II) has strong anti-human immunodeficiency virus (HIV) activity, and that T22 inhibits T cell-line-tropic HIV-1 infection mediated by CXCR4/fusin. T22 is an 18-residue peptide amide, which takes an antiparallel beta-sheet structure that is maintained by two disulfide bridges. Structure-activity relationship (SAR) studies on T22 have disclosed the contributions of each region of T22 to activity or cytotoxicity, and have provided the following useful information to develop new CXCR4 antagonists: The number of Arg residues in the N-terminal and C-terminal regions of T22 is closely related to anti-HIV activity. Addition of a variety of functional groups at the N-terminal end results in increases in activity. Disulfide rings, especially the major disulfide loop, are indispensable for anti-HIV activity and maintenance of the beta-sheet structure. Trp3 can be replaced by other aromatic residues (Tyr, Phe and L-2-naphthylalanine). Between two repeats of Tyr-Arg-Lys, which are a characteristic structure in T22, Tyr-Arg-Lys in the N-terminal portion is more closely associated with anti-HIV activity and maintenance of the beta-sheet structure. A positive charge in the side chain at the (i + 1) position of the beta-turn region is necessary for strong activity. Through these studies, we have found several compounds having higher selectivity indexes (50% cytotoxic concentration/50% effective concentration) than that of T22.

Amino Acid Sequence↗
PubMed1998

Establishment of monoclonal antibody, gp21-34, against HTLV-II envelope protein (p20E).

A monoclonal antibody (MAb), gp21-34, specifically reactive with human T-lymphotropic virus type-II (HTLV-II) transmembranous envelope glycoprotein (p20E) was developed by immunization with a recombinant protein fused with thioredoxin moiety at the N-terminal portion. This MAb, which belongs to the IgG1 kappa subclass, reacted with HTLV-II infected cell lines (TON-1, C3-44, and Si-IIA) by IFA, but not with HTLV-I infected cell lines (TCL-Kan and MT-2). By Western blot analysis, this MAb reacted with p20E of HTLV-II lysates but not with HTLV-I lysates. Some epitope analyses with synthetic peptides were carried out to look for a plausible linear epitope in the C-terminal region of p20E.

Amino Acid Sequence↗
PubMed1998

Induction of cross-reactivity in an endogenous viral peptide non-reactive to FBL-3 tumor-specific helper T-cell clones.

We previously reported a helper T-cell (Th) epitope (peptide i) which corresponded to the sequence ranging from positions 462 to 479 from the N-terminus of the Friend-murine leukemia virus (F-MuLV) envelope protein (env462-479). Homologous sequences exist in both Moloney-murine leukemia (M-MuLV env452-469) and endogenous AKV (AKV env453-470) viruses, which differ from F-MuLV env462-479 in 5 and 7 amino acids, respectively. However, peptide i-specific Th clones did not respond to either of the corresponding exogenous or endogenous peptides. One amino acid substitution in M-MuLV env452-469 (Asn to Tyr at position 465: N465Y) and three amino acids in AKV env453-470 (H460S, A466Y and Y468H) endowed both peptides with the reactivity to one of the Th clones, F5-5, almost to the same degree as peptide i. However, the other Th clones responded differently to each of the modified endogenous peptides substituted by one to three amino acids. The cells responsive to the cross-reactive peptides occupied only a minor portion, if any, of the bulk cultured lymph node cells from peptide i-immune mice, and in particular, no significant response to the modified endogenous peptides was observed in repeated experiments. The exchange of at least 3 residues was necessary for the endogenous peptide to acquire sufficient cross-reactivity to two of the three Th clones. However, it was noticeable that a single substitution of alanine by tyrosine at the dominant T-cell receptor (TCR) contact position of the peptide i(e) generated a weak but significant cross-reactivity to one of the three Th clones in this study. Thus, peptides of endogenous retroviral origin that would be modified by mutational events might become 'non-self' and prime Th cells leading to auto-antibody production and resulting in autoimmune disease.

Amino Acid Sequence↗
PubMed1998

Utilization of proteinase K-treated cells as lipopolysaccharide antigens for the serodiagnosis of Helicobacter pylori infections.

We have evaluated the use of proteinase K (PK)-treated cells isolated from Helicobacter pylori as lipopolysaccharide (LPS) antigens in an immunoblot assay and an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of H. pylori infection. The sera from patients with chronic gastritis, gastric ulcer, duodenal ulcer or gastric cancer, and from healthy adults with or without H. pylori infection were assayed with three commercial serodiagnostic kits (HM-CAP, Helico-G, and G.A.P. II) and novel methods relying on the use of PK-treated cells. The PK-treated cells used in these assays were selected on the basis of their possibility to possess a common epitope in the O-polysaccharides of H. pylori, which is known to be highly immunogenic in humans. Of the sera from these patients, 71-94% were positive with the commercial kits, 97% with immunoblot assay, and 90% with ELISA. On the other hand, of the healthy adults infected with H. pylori, 72-97% were positive with the commercial kits, 86% with immunoblot assay, and 72% with ELISA. PK-treated cells that did not contain the common epitope were unsuitable as an antigen for immunoblot assay or ELISA. Furthermore, the reactivity of these sera reacted specifically with H. pylori PK-treated cells but not with LPSs from other gram-negative bacteria, such as Campylobacter, Proteus, Bordetella, and Salmonella. These results demonstrate that the serological assays relying on the use of H. pylori PK-treated cells possessing a highly antigenic epitope are potentially useful as a serodiagnostic test for H. pylori infection.

Adult↗
PubMed1998

Apoptosis of lymphocytes in mice administered lipopolysaccharide from Leptospira interrogans.

We report that administration of leptospiral lipopolysaccharide (LPS) in mice results in massive surface marker changes in the lymphocytes of the spleen. It appears that many of these changes relate to the large number of cells undergoing apoptosis. It is also shown that tumor necrosis factor-alpha (TNF-alpha) induces similar effects and is produced in large quantities after injection of leptospiral LPS. It is likely that cytokines such as TNF-alpha are involved in apoptosis.

Animals↗
PubMed1998

[Enterohemorrhagic Escherichia coli O157 outbreak in Obihiro-City--study on antibiotic susceptivity and plasmid profiles].

The drug-resistance patterns and plasmid profiles of 147 isolates (patient origin 142 and food origin 5 isolates) from the outbreak of enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection in Obihiro-city Hokkaido in late October, 1996, were examined. Thirty-six isolates were resistant to tetracycline (TC) (24.5%), 15 of which were resistant to both streptomycin and TC. The minimal growth inhibitory concentration (MIC) of fosfomycine (FOM) was examined, confirming that MIC changed by the cultivation conditions, that is 12.5 micrograms/ml at the aerobic condition, 1.6 micrograms/ml at the anaerobic condition and 3.2 micrograms/ml on blood agar plates. Furthermore, though E. coli O157 could not be detected once by the FOM medication, FOM sensitivity of the patient origin O157 isolates who became O157-positive again was examined. Any changes in FOM sensitivity were not observed. Plasmid profiles of all isolates were divided by 4 patterns from A to D. The most dominant pattern was type A, and plasmid profiles of food origin O157 belonged to pattern A. In 9 examples of the person-to-person infection in the family, plasmid patterns of O157 isolates were the same to each other, even though drug-resistant patterns were different. In 13 patients developing the duration of excretion of EHEC, the changes of the drug-resistance patterns were correlated with the changes of plasmid profiles. By comparing plasmid profiles and TC resistance, it was suggested that TC resistance was controlled on a plasmid. Since food origin O157 isolates were sensitive to all drugs and presenting the same plasmid profiles, demonstrating that TC resistance and plasmid are newly added to the bacterial cells while food origin O157 isolates passe inside the human body.

Adolescent↗
PubMed1998

Effect of rebamipide, a novel antiulcer agent, on Helicobacter pylori adhesion to gastric epithelial cells.

Helicobacter pylori is a major etiological agent in gastroduodenal disorders. The adhesion of H. pylori to human gastric epithelial cells is the initial step of H. pylori infection. Inhibition of H. pylori adhesion is thus a therapeutic target in the prevention of H. pylori infection. Experiments were performed to evaluate the effect of rebamipide, a novel antiulcer agent, on H. pylori adhesion to gastric epithelial cells. MKN-28 and MKN-45 cells, derived from human gastric carcinomas, were used as target cells. Ten H. pylori strains isolated from patients with chronic gastritis and gastric ulcer were used in the study. We evaluated the effect of rebamipide on H. pylori adhesion to MKN-28 and MKN-45 cells quantitatively using our previously established enzyme-linked immunosorbent assay. The adhesion of H. pylori to MKN-28 and MKN-45 cells was significantly inhibited by pretreatment of these cells with 100 microg of rebamipide per ml. However, the adhesion was not affected by the pretreatment of H. pylori with rebamipide. On the other hand, the viabilities of H. pylori, MKN-28 cells, and MKN-45 cells were not affected by rebamipide. Our studies suggest that rebamipide inhibits the adhesion of H. pylori to gastric epithelial cells.

Alanine↗
PubMed1998

Analysis of immunoglobulin A antibodies to Helicobacter pylori in serum and gastric juice in relation to mucosal inflammation.

Helicobacter pylori is a major etiologic agent in gastroduodenal disorders. In this study, immunoglobulin A (IgA) antibodies to H. pylori antigens were evaluated in serum and gastric juice specimens obtained from patients with gastritis or peptic ulcers by utilizing antibody capture enzyme-linked immunosorbent assays (ACELISAs). Urease alpha subunit (UA), urease beta subunit (UB), the 66-kDa heat shock protein (HSP), and the 25-kDa protein (25K) were used as antigens for the ACELISAs. The antibody titers of the ACELISAs reflect the ratio of H. pylori-specific IgA to total IgA. The ratio is stable, although the antibody concentration fluctuates in gastric juice. By using ACELISAs it was possible to evaluate quantitatively not only serum IgA antibodies but also gastric juice secretory IgA (S-IgA) antibodies. In both serum IgA and gastric juice S-IgA ACELISAs, the titers of antibody to HSP and 25K were remarkably correlated with the histologic grade of gastritis, whereas those to UA and UB were not strongly correlated with histologic grade. Thus, it is useful for estimating the histologic grade of gastritis to quantify serum IgA and gastric juice S-IgA antibodies to HSP and 25K.

Adolescent↗
PubMed1998

Role of tumor necrosis factor alpha in gnotobiotic mice infected with an Escherichia coli O157:H7 strain.

Gnotobiotic mice inoculated with an enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain developed a flaccid paresis, usually culminating in death. The bacteria colonized feces at 10(9) to 10(10) CFU per g (inoculum size: 2.0 x 10(9) CFU/mouse), and Shiga-like toxins (SLTs) were detected in the feces. A microscopic examination of colons showed mild inflammatory cell infiltration, thinning of the intestinal wall, or necrotic foci. Necrosis of tubular cells was noted in these symptomatic mice. Microhemorrhage, thrombosis, and edematous changes of the brain were also seen. Inflammatory cytokines, tumor necrosis factor alpha (TNF-alpha), interleukin 1alpha (IL-1alpha), and IL-6, were detected in the kidney after EHEC infection, but not in the serum. In the brain, only TNF-alpha was detected. When 2.0 x 10(2) CFU of EHEC O157:H7 was fed to germ-free mice, the number of bacteria began to rise rapidly on day 1 and was maintained at 10(8)to 10(9) CFU/g of feces. SLTs were detected in the feces of the mice. However, the mice showed no histological changes and no cytokine responses, similar to what was found for controls. Treatment with TNF-alpha modified the clinical neural signs, histopathological changes, and cytokine responses; mice treated with TNF-alpha developed severe neurotoxic symptoms and had higher frequencies of systemic symptoms and glomerular pathology. Strong cytokine responses were seen in the kidney and brain. Serum cytokines were also detected in this group. In contrast, a TNF-alpha inhibitor (protease inhibitor) inhibited these responses, especially in the brain. However, local synthesis of the cytokines was observed in the kidney. Thus, TNF-alpha and the other proinflammatory cytokines could be important in modifying the disease caused by EHEC.

Animals↗
PubMed1998

Human antibody response to Helicobacter pylori lipopolysaccharide: presence of an immunodominant epitope in the polysaccharide chain of lipopolysaccharide.

We have examined the antibody response to Helicobacter pylori lipopolysaccharides (LPS) in humans. We used sera from patients with gastroduodenal diseases and healthy adults infected or not infected with H. pylori. Data from the experiments for antibody binding to LPS suggested that the polysaccharide chains from many H. pylori strains showed high immunogenicity in humans. Sera from most (above 70%) H. pylori-infected individuals contained immunoglobulin G (IgG) antibodies against the polysaccharide region highly immunogenic H. pylori LPS. The IgG titers of individual serum samples that reacted strongly with highly immunogenic LPS were quite similar (r2 = 0.84 to 0.98). The results suggest wide distribution among H. pylori strains of a highly antigenic epitope in the polysaccharide moieties of their LPS. Also, the similarity in the titers of individual serum samples against highly immunogenic LPS points to the existence of epitopes sharing a common structural motif. However, some strains showed low antigenicity, even those with polysaccharide-carrying LPS. The dominant subclass of IgG that reacted with the highly immunogenic LPS was IgG2, which was preferentially raised against polysaccharide antigens. Recently, a structure that mimics that of the Lewis antigens was identified in the O-polysaccharide fraction of H. pylori LPS; however, no correlation between antigenicity of the polysaccharide chain in humans and the presence of Lewis antigens was found. The IgA and IgM titers against H. pylori LPS seemed to be mostly nonspecific and directed against lipid A. In a few cases, however, sera from individuals infected with H. pylori gave strong IgA and IgM titers against the highly immunogenic polysaccharide. In conclusion, the LPS of many H. pylori strains possess an antigenic epitope in their polysaccharide regions that is immunogenic in humans. However, our results show that the antigenic epitope is unlikely to be immunologically related to structures mimicking Lewis antigens.

Adult↗
PubMed1998

Beta-adrenergic receptor number in human lymphocytes is inversely correlated with aerobic capacity.

In the present study, the relationships between beta-adrenergic receptor (beta-AR) expression and aerobic capacity evaluated by maximal oxygen consumption (.VO2max) and oxygen consumption level at ventilatory threshold (.VO2@VT) were investigated. Seventeen physically untrained and 25 trained men participated in the study. After supine resting, the peripheral blood was sampled for preparation of lymphocytes, the model cell used to analyze the beta-AR state. The total number of beta-AR in lymphocytes (beta-ARtotal) was inversely correlated with the VO2 max (r = -0. 368; P < 0.05) and the VO2@VT (r = -0.359; P < 0.05). Similar relationships were also observed between the number of beta-AR in cell surface and both VO2 max (r = -0.491; P < 0.05) and VO2@VT (r = -0.498; P < 0.05). However, no correlation was obtained between the number of beta-AR in intracellular compartments and either VO2 max or VO2@VT. The beta2-AR mRNA level quantified by the use of competitive reverse transcription-polymerase chain reaction was inversely correlated with VO2@VT (r = -0.567; P < 0.05) and positively correlated with beta-ARtotal (r = 0.521; P < 0.05). These findings suggest that the beta-AR number in lymphocytes is inversely correlated with aerobic capacity. This relationship may be explained by downregulation of beta-AR, including internalization with subsequent degradation of the receptors and inhibition of the beta-AR biosynthesis.

Adolescent↗