Search PubMed⌕ Search

Biomedical subjects

Y Yokomizo

Publications and source records attributed to Y Yokomizo.

At least 55 records · Page 3Linked to original sources
PubMed1999

Isolation of parapoxvirus from a cow treated with interferon-gamma.

A virus was isolated from peripheral blood leukocytes of a cow which was kept in an isolated pen after it was injected with recombinant bovine interferon-gamma. The virus was identified as a member of genus Parapoxvirus in the family Poxviridae on the basis of electron microscopic observations and serological tests. Parapoxvirus has seldom been isolated other than from papular lesions, the characteristic sign of parapoxvirus infection. This is the first report of parapoxvirus isolation from the peripheral blood of a cow without any clinical signs. These results show that parapoxviruses are capable of causing persistent infection in cattle without clinical signs and can be activated by stress factors that induce modification of immune reactions. Relationships between the isolated virus and other parapoxviruses isolated previously from cattle in Japan were investigated and discussed.

Animals↗
PubMed1999

Molecular cloning of porcine interleukin-1beta converting enzyme and differential gene expression of IL-1beta converting enzyme, IL-1beta, and IL-18 in porcine alveolar macrophages.

We have cloned and sequenced a cDNA that contains the coding sequence of porcine interleukin-1beta (IL-1beta) converting enzyme (ICE). Using degenerate oligonucleotide primers based on the amino acid sequences of the human, murine, and rat ICE, we performed the reverse transcription polymerase chain reaction (RT-PCR) with total RNA prepared from porcine alveolar macrophages stimulated with lipopolysaccharide (LPS) to clone the cDNA of porcine ICE. The open reading frame (ORF) of the porcine ICE cDNA is 1215 base pairs (bp) in length and encodes 404 amino acids. The predicted amino acid sequence is 72.5%, 62.6%, and 64.1% homologous to the human, murine, and rat amino acid sequences, respectively. The kinetics of mRNA expression of ICE, IL-1beta, and IL-18 in porcine alveolar macrophages after LPS stimulation revealed that ICE transcripts were weakly expressed in nonstimulated condition and upregulated after LPS stimulation. Moreover, IL-1beta and IL-18 transcripts were differently expressed after LPS stimulation.

Amino Acid Sequence↗
PubMed1999

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors. III.

In order to improve the biological characteristics of DA-3934 (5), a novel gastrin/cholecystokinin (CCK)-B receptor antagonist, phenoxyacetic acid derivatives replacing the N-methyl-N-phenylcarbamoylmethyl moiety of 5 with various alkyl chains have been synthesized and their biological activity evaluated. The relationship between the structure of these compounds and their human gastrin receptor binding affinity showed that there should be the optimal size among the various N-alkyl chains. Also a significant increase in the receptor binding affinity was achieved by several compounds. Among those compounds, 2-[3-[3- [N-cyclohexylmethyl-N-[2-(N-methyl- N-phenylcarbamoylmethoxy)phenyl]carbamoylmethyl]ureido]pheny l]acetic acid (22c) and (+/-)-2-[3-[3-[N-[2-(N-methyl-N- phenylcarbamoylmethoxy)phenyl]-N-(3-methylpentyl)carbamoy lmethyl]ureido] phenyl]acetic acid (22h) exhibited high affinity for human gastrin receptors and were also more potent inhibitors in a pentagastrin-induced gastric acid secretion model than the parent compound, 5. The ED50 values of these compounds when administered intraduodenally to rats were 0.12 and 0.63 mg/kg, respectively.

Acetates↗
PubMed1999

Effects of recombinant bovine granulocyte-macrophage colony-stimulating factor on bovine peripheral blood neutrophil functions in vitro and in vivo.

Effects of recombinant bovine granulocyte-macrophage colony-stimulating factor (rboGM-CSF) on bactericidal activity of bovine peripheral blood neutrophils in vitro and in vivo were studied. In in vitro experiment, bovine blood neutrophils were cultured for 9 hr in media containing 0.005, 0.05 or 0.5 microg/ml of rboGM-CSF. Neutrophils treated with rboGM-CSF showed significantly higher luminol-dependent chemiluminescence (LDCL) than control cells. In in vivo experiment, neutrophils isolated from cows injected 5.0 microg/kg of rboGM-CSF showed significantly higher Nitrobluetetrazolium (NBT) reduction value than that from control cows 24 hr post injection. Total leukocyte counts of cows injected rboGM-CSF sharply decreased 6 hr post injection and recovered to normal level 2 days post injection. Body temperature of these cows rose 6 hr post injection and back to normal level at 24 hr post injection. It was suggested that rboGM-CSF enhanced bactericidal activity of bovine neutrophils both in vitro and in vivo.

Animals↗
PubMed1999

Effects of lipopolysaccharide on production of interleukin-1 and interleukin-6 by bovine mammary epithelial cells in vitro.

This investigation was performed to determine the effect of lipopolysaccharide (LPS) on production of interleukin (IL)-1 and IL-6 by bovine mammary epithelial cells in vitro. After confluence, the cells were stimulated with LPS (0.1, 1.0 or 10 micrograms/ml) for 4, 8, 24, and 48 hr. LPS increased production of both IL-1 and IL-6 production from mammary cells in a dose dependent manner. The expression of mRNA for IL-1 receptor antagonist (IL-1ra) was demonstrated by reverse transcription-polymerase chain reaction in bovine mammary epithelial cells.

Animals↗
PubMed1999

Effects of isoprothiolane on cell growth of cultured bovine mammary epithelial cells.

This study was performed to investigate the effects of isoprothiolane on cell growth and the production of interleukin (IL)-1 and IL-6 by bovine mammary epithelial cells in vitro. Isoprothiolane increased proliferation of mammary epithelial cells in a dose-dependent manner at the concentration of 0.05 to 5 microM when cultured either with or without serum-supplemented medium. In contrast, isoprothiolane (0.0005-5 microM) significantly inhibited the production of IL-1 and IL-6 by mammary epithelial cells. Moreover, the cytokines, IL-1alpha, IL-1beta, IL-6, and tumor necrosis factor (TNF)-alpha tended to inhibit the proliferation of mammary epithelial cells in a dose-dependent manner. These results indicated that isoprothiolane regulated mammary epithelial cell growth in vitro possibly by modulating the production of cytokines.

Animals↗
PubMed1999

Pathological and immunological findings of athymic nude and congenic wild type BALB/c mice experimentally infected with Neospora caninum.

Neospora is a cyst-forming coccidian parasite that causes abortions and neuromuscular disorders in a wide variety of mammals. Japanese bovine isolate JPA1 was inoculated intraperitoneally into BALB/c nu/ nu (athymic nude) and BALB/c (congenic wild type) female mice to examine the distribution of parasites and resistance mechanisms to Neospora infection. All the athymic nude mice died within 28 days after intraperitoneal injection of 2 x 10(5) JPA1 tachyzoites, whereas all the congenic wild type mice survived without exhibiting any clinical signs. Tachyzoites were identified in the uterus and pancreas and later spread to many other organs. Most tachyzoites identified in the necrotic foci were localized in the epithelium of the venules and capillaries. Nude mice developed high level of serum interferon-gamma and interleukin-6 as infection proceeded. Inflammatory response to Neospora infection might be mediated by Th1-type dependent cellular immunity.

Animals↗
PubMed1998

Development of maternal IgG-free chick obtained from surgically bursectomized hen.

IgG-free eggs and chicks were developed, so as to study the role of maternal IgG in the development of the immune system. Surgical bursectomy on the 18th day of incubation deprived chickens of B cells and eliminated IgG synthesis. Bursectomized chickens are usually dead before sexual maturity under conventional conditions. When surgically bursectomized chickens were housed in an isolated clean room and antibiotics were administered to them, they could survive to sexual maturity. Finally, we succeeded in obtaining IgG-free fertilized eggs and maternal IgG-free chicks from surgically bursectomized hens. The amount of yolk IgG in IgG-free eggs was one-ten thousandth less than that in normal eggs. The level of IgM in the serum of maternal IgG-free chicks reached six times higher than that of normal chicks 5 days after hatching.

Animals↗
PubMed1998

A comparative study of germinal center: fowls and mammals.

The mammalian germinal center is organized into a dark zone containing proliferating centroblasts and a light zone filled with nondividing B cells (called centrocytes), follicular dendritic cells and a few scattered T cells. We clarified these two zones in the chicken germinal center with immunohistology. Proliferating cells and immunoglobulin negative cells were detected in the circumference ring of the chicken germinal center. The central part of the chicken germinal center contained B cells expressing immunoglobulin, follicular dendritic cells and a few T cells. Most of the B cells in the central part of the chicken germinal center did not enter into the S phase. These results suggest that the chicken germinal center is also organized into the dark zone (the circumference ring of germinal center) and the light zone (the central part of germinal center).

Animals↗
PubMed1998

Construction and vaccine potential of acapsular mutants of Erysipelothrix rhusiopathiae: use of excision of Tn916 to inactivate a target gene.

We previously showed that acapsular transposon Tn916 mutants of Erysipelothrix rhusiopathiae are avirulent for mice. In this study, we constructed nonreverting acapsular mutants and examined the vaccine potential of the mutants in mice. A representative acapsular transposon mutant, 33H6, was plated on selective agar containing autoclaved chlortetracycline and quinaldic acid, and two tetracycline-sensitive mutants were obtained. Sequence analysis of chromosomal regions of the mutants in which Tn916 had flanked revealed that Tn916 had spontaneously excised from the region and that the six new nucleotides, which were presumably inserted with Tn916 into 33H6 chromosome, substituted for those present at the insertion site. The mutants were confirmed to be devoid of capsular antigen by Western immunoblotting and were nonvirulent for mice (subcutaneous 50% lethal dose [LD50], >10(9) CFU). The safety and efficacy of acapsular mutants for live vaccines was further studied by using one mutant strain, named YS-1. The YS-1 bacteria were cleared from the skin sites of inoculation, livers, and spleens of the inoculated mice by 7 days after subcutaneous (s.c.) inoculation. Mice immunized s.c. with doses ranging from 2 x 10(4) to 2 x 10(8) CFU of strain YS-1 were completely protected against challenge with 100 LD50 of the homologous, highly virulent strain Fujisawa-SmR 21 days postimmunization, and protective immunity conferred by immunization with 2 x 10(8) CFU of the strain lasted for as long as the 3 months of the observation period. In passive immunization experiments, sera collected from mice immunized with strain YS-1 at days 14 and 21 postimmunization provided protection against challenge with Fujisawa-SmR, whereas sera collected at days 4 and 7 did not. Furthermore, specific spleen cell responses to E. rhusiopathiae antigens were observed in mice immunized with strain YS-1, and cross-protection against the antigenically heterologous bacterium Listeria monocytogenes was observed at 7 days after immunization in the mice, suggesting that cell-mediated immunity had been induced. These results suggest that E. rhusiopathiae YS-1 may be a suitable choice for further studies of vaccine efficacy in swine.

Animals↗
PubMed1998

Use of an enrichment broth cultivation-PCR combination assay for rapid diagnosis of swine erysipelas.

We have previously described the creation by Tn916 mutagenesis of avirulent transposition mutants from a highly virulent strain of Erysipelothrix rhusiopathiae, the causative agent of swine erysipelas. In this study, we cloned a 2.2-kb DNA fragment which flanked the Tn916 insertion in an avirulent mutant (strain 33H6) and evaluated the possibility that this region could be used for the specific detection of E. rhusiopathiae. According to the sequences of this region, oligonucleotide primers were designed to amplify a 937-bp fragment of the E. rhusiopathiae chromosome by PCR. The specificity of the PCR was investigated by analyzing 64 strains of Erysipelothrix species and 27 strains of other genera different from Erysipelothrix. A 937-bp DNA fragment could be amplified from all E. rhusiopathiae strains tested, and no amplification was observed by using DNAs from the other species tested. To make a rapid and definite diagnosis of swine erysipelas in slaughterhouses, we developed an enrichment broth cultivation-PCR combination assay, which used a commercially available DNA extraction kit, to identify E. rhusiopathiae in the specimens from swine with arthritis. After samples were enriched in selective broth culture, detection of E. rhusiopathiae was tested by either conventional methods or the PCR. Of 102 samples tested, 15 samples were positive by conventional methods and 12 of the 15 samples were positive by the PCR. The detection limit of the PCR was 10(3) CFU per reaction mixture for the PCR-positive samples. These results indicate that this PCR technique could be used as a first-line screening technique for the specific detection of E. rhusiopathiae in specimens.

Animals↗
PubMed1998

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors.

A novel series of phenoxyacetic acid derivatives was synthesized based on considerations of the three-dimensional structural similarity of YM022 and RP72540. The gastrin/cholecystokinin (CCK)-B and CCK-A receptor antagonist activities of these compounds were evaluated by investigation of their affinities for human gastrin/CCK-B receptors and human CCK-A receptors, respectively. It was found that N-methyl-N-phenyl-2-[2-[N-(N-methyl-N-phenyl-carbamoylmethyl)-N-[2 -[3-(3- methylphenyl)ureido]acetyl]amino]phenoxy]acetamide (20k, DZ-3514) exhibited high affinity for gastrin/CCK-B receptors and high selectivity over CCK-A receptors.

Acetamides↗
PubMed1998

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors. II.

A series of phenoxyacetanilide derivatives was synthesized and their antagonist activities for human gastrin/cholecystokinin (CCK)-B and CCK-A receptors were evaluated. Among the compounds synthesized, 2-[3-[3-[N-[2-(N-methyl-N-phenylcarbamoylmethoxy)phenyl]-N-(N-meth yl-N- phenylcarbamoylmethyl)carbamoylmethyl]-ureido]phenyl]acetic acid (20i, DA-3934) exhibited high affinity for gastrin/CCK-B receptors and high selectivity over CCK-A receptors. DA-3934 and its methyl ester derivative inhibited pentagastrin-induced gastric acid secretion in rats in a dose-dependent manner.

Acetates↗
PubMed1998

Production of recombinant porcine tumor necrosis factor alpha in a baculovirus expression system.

Porcine tumor necrosis factor alpha (TNF-alpha) was produced using a baculovirus system in Spodoptera frugiperda (SF21AE) cells. Cytotoxic activity was detected in supernatant of sonicated SF21AE cells infected with recombinant viruses. The recombinant protein was also demonstrated to be functionally active by its ability to cause apoptosis in Wehi 164 cells. Three distinct bands of 26, 17 and 14 kDa were revealed by Western blot analysis using anti-human TNF-alpha antibody. Moreover, the anti-human TNF-alpha antiserum significantly neutralized the cytotoxic activity of the supernatant of sonicated SF21AE cells infected with recombinant viruses.

Animals↗
PubMed1998

Anti-viral effect of interferon-alpha on bovine viral diarrhea virus.

To get basic information to control persistent virus infection among domestic animals by cytokines, the antiviral activity of four natural human cytokines against bovine viral diarrhea virus (BVDV) was evaluated. Normal bovine peripheral blood mononuclear leukocytes (PBML) and fetal bovine muscular cells (FBMC) were treated with varying doses of human interferon (IFN)-alpha, IFN-gamma, tumor necrosis factor (TNF)-alpha and TNF-beta. The antiviral activity in treated cells was measured by the titration of virus infectivity in comparison with non-treated controls. IFN-alpha significantly suppressed virus growth in both PBML and FBMC. The growth of two cytopathogenic and two noncytopathogenic strains was suppressed in the presence of more than 10(3) u/ml of IFN-alpha. Addition of either TNF-alpha or TNF-beta to IFN-alpha did not potentiate the suppressive effect. IFN-alpha also suppressed the replication of BVDV in PBML from cattle persistently infected with BVDV.

Animals↗