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Y Sakoda

Publications and source records attributed to Y Sakoda.

At least 19 recordsLinked to original sources
PubMed2006

Development of an immunochromatographic test kit for rapid detection of bovine viral diarrhea virus antigen.

An immunochromatographic test was developed for rapid diagnosis of bovine viral diarrhea virus (BVDV) infections using monoclonal antibodies against the nonstructural protein, NS3, of the virus. The kit detected specifically the NS3 of various BVDV strains. Using the kit, leukocyte extracts of cattle infected persistently with BVDV were found positive while those of healthy cattle were negative. The sensitivity and specificity of this kit in compared with virus isolation were 100% and 97.2%, respectively. Furthermore, the test also gave positive results for calves infected acutely with BVDV in experimental infection. The BVDV antigen was detected in 1 ml of blood using a relatively simple procedure. This test kit should be useful for rapid diagnosis of BVD.

Animals↗
PubMed2006

Pathogenicity of a highly pathogenic avian influenza virus, A/chicken/Yamaguchi/7/04 (H5N1) in different species of birds and mammals.

Outbreaks of highly pathogenic avian influenza (HPAI) have been occurring in domestic poultry in Asia since 1996. In the beginning of 2004, HPAI outbreaks were caused by H5N1 virus in two farms and a group of pet chickens in different areas of Japan. In the present study, the pathogenicity of A/chicken/Yamaguchi/7/04 (H5N1), which had been isolated from a dead chicken during the first outbreak in Japan, was assessed in chickens, quails, budgerigars, ducklings, mice, and miniature pigs by experimental infection. The virus was highly pathogenic to all the birds tested. Mice were susceptible to infection with a low mortality rate and miniature pigs were resistant to infection with the virus.

Animals↗
PubMed2006

Library of influenza virus strains for vaccine and diagnostic use against highly pathogenic avian influenza and human pandemics.

To prepare for the emergence of pandemic influenza in birds and mammals including humans, we have carried out global surveillance of avian influenza. Influenza A viruses of 48 combinations of 15 HA and 9 NA subtypes out of 135 theoretical combinations have been isolated from faecal samples of ducks in Alaska, Siberia, Mongolia, Taiwan, China and Japan. So far, viruses of 73 other combinations have been generated by genetic reassortment in chicken embryos. Thus, avian influenza viruses of 121 combinations of HA and NA subtypes have been stocked for use in vaccine and diagnosis. Their pathogenicity, antigenicity, genetic information, and yield in chicken embryo have been analysed and registered in the database.

Alaska↗
PubMed2005

Genetic recombination at different points in the Npro-coding region of bovine viral diarrhea viruses and the potentials to change their antigenicities and pathogenicities.

Cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strain KS86-1 cp was isolated from a cow persistently infected with non-cytopathogenic (ncp) BVDV strain KS86-ncp after development of mucosal disease by superinfection with cp BVDV strain Nose. cp BVDV strains 799cp and 839cp were also isolated from independent cattle that developed mucosal disease by superinfection with cp BVDV KS86-1cp. In the present study, genetic analysis revealed that the genes of cp BVDV strains 799cp and 839cp were chimeras between the genes of the persisting ncp BVDVs and that of superinfecting KS86-1cp. The genetic recombination that generates 799cp occurred between the identical points in the N(pro) gene region, whereas genetic recombination that generates 839cp occurred between different points in the N(pro) gene region. Both 799cp and 839cp were inherited Jiv gene of KS86-1cp strain and envelope protein genes of the persisting viruses. In addition, neutralization test disclosed that antigenicities of 799cp, 839cp, and KS86-1cp were also similar to each persisting virus. These findings indicate that exogenous cp BVDV containing insertion of Jiv gene in the 5 terminal region can induce genetic recombination with the original ncp BVDV at different points in the N(pro) gene region, and those viruses have high potential to change those antigenicities and pathogenicities by RNA recombination.

Animals↗
PubMed2005

Pathogenicity of H5 influenza viruses for ducks.

Four H5N1 highly pathogenic avian influenza (HPAI) viruses and an avirulent reassortant H5N1 virus were tested for their pathogenicity in domestic ducks. A/chicken/Yamaguchi/7/04 (H5N1) (Ck/Yamaguchi/04) isolated from a dead bird during the HPAI outbreak in Japan and A/duck/Yokohama/aq-10/03 (H5N1) (Dk/Yokohama/03) isolated from duck meat at a quarantine inspection for importation from China replicated in multiple organs including the brain of ducks. The ducks infected with Ck/Yamaguchi/04 did not show any clinical signs, while those infected with Dk/Yokohama/03 showed neurological signs. The ducks infected either with A/Hong Kong/483/97 (H5N1) or A/tern/South Africa/61 (H5N3), or with an avirulent H5N1 reassortant, did not show any clinical signs. Virus-specific antibodies were detected in the sera of the ducks infected with each of the five strains tested, indicating that all of the viral strains infected and replicated in the birds. Dk/Yokohama/03 grew in multiple organs more rapidly than did Ck/Yamaguchi/04. Considerable titers of virus were detected in the brain of the ducks infected with Dk/Yokohama/03 and these birds showed neurological signs. The present results demonstrate that the pathogenicity of influenza viruses for ducks does not correlate with that for chickens and that replication of the virus in the brain is critical for ducks to show neurological signs.

Animals↗
PubMed2004

Co-infection of Staphylococcus aureus or Haemophilus paragallinarum exacerbates H9N2 influenza A virus infection in chickens.

H9N2 influenza viruses are frequently isolated from chicken meat and bone marrow imported from China to Japan since 2001. These isolates were experimentally inoculated into specific pathogen-free chickens intranasally. Viruses were recovered from the meat and bone marrow of birds showing no overt signs. On the other hand, chickens co-infected with H9N2 virus and either Staphylococcus aureus or Haemophilus paragallinarum showed clinical signs severer than those shown by birds infected only with the virus alone or each of the bacteria alone. In addition, H9N2 viruses were more efficiently recovered from the chickens co-infected with S. aureus or H. paragallinarum than those from the birds infected with only the virus. The present results indicate that co-infection of H9N2 influenza virus with S. aureus or H. paragallinarum enhances the replication of the virus in chickens, resulting in exacerbation of the H9N2 virus infection.

Animals↗
PubMed2001

Genomic and serological diversity of bovine viral diarrhea virus in Japan.

Genomic properties of 62 field isolates of bovine viral diarrhea virus (BVDV) collected from 1974 to 1999 in Japan were investigated. The 5' untranslated region (UTR) was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) and the 244 to 247 base nucleotide sequences were determined. Serological properties were also characterized by the cross-neutralization test using antisera against the representative strain of the classified genotype. Using phylogenetic tree analysis, BVDV 1 was subdivided into two major clusters, BVDV-1a (29 isolates) and BVDV-1b (27 isolates). In group 1a, 3 differed from the other viruses, and were classified in a branch assigned as 1a'. However, 4 isolates (So CP/75, 190 CP, 190 NCP and KS86-1-NCP) could not be assigned to group 1a or 1b. In comparison with the published sequence data, KS86-1-NCP, 190 CP and 190 NCP were similar to the Southern Africa isolates that have recently been proposed as BVDV 1c. The 5' UTR sequence of So CP/75 was unique among those of BVDV 1, suggesting that the isolate should be classified into a new genotype. Only 2 out of 62 isolates collected in 1989 and 1990 were identified as BVDV 2. The results of the cross-neutralization test strongly supported these data, suggesting a close correlation between the 5' UTR sequence and the antigenicity of BVDV.

5' Untranslated Regions↗
PubMed2001

An attenuating mutation in the 2A protease of swine vesicular disease virus, a picornavirus, regulates cap- and internal ribosome entry site-dependent protein synthesis.

Virulent and avirulent strains of swine vesicular disease virus (SVDV), a picornavirus, have been characterized previously. The major determinants for attenuation have been mapped to specific residues in the 1D-2A-coding region. The properties of the 2A proteases from the virulent and avirulent strains of SVDV have now been examined. Both proteases efficiently cleaved the 1D/2A junction in vitro and in vivo. However, the 2A protease of the avirulent strain of SVDV was much less effective than the virulent-virus 2A protease at inducing cleavage of translation initiation factor eIF4GI within transfected cells. Hence the virulent-virus 2A protease is much more effective at inhibiting cap-dependent protein synthesis. Furthermore, the virulent-virus 2A protease strongly stimulated the internal ribosome entry sites (IRESs) from coxsackievirus B4 and from SVDV, while the avirulent-virus 2A protease was significantly less active in these assays. Thus, the different properties of the 2A proteases from the virulent and avirulent strains of SVDV in regulating protein synthesis initiation reflect the distinct pathogenic properties of the viruses from which they are derived. A single amino acid substitution, adjacent to His21 of the catalytic triad, is sufficient to confer the characteristics of the virulent-strain 2A protease on the avirulent-strain protease. It is concluded that the efficiency of picornavirus protein synthesis, controlled directly by the IRES or indirectly by the 2A protease, can determine virus virulence.

Animals↗
PubMed2001

Characterization of classical swine fever virus associated with defective interfering particles containing a cytopathogenic subgenomic RNA isolated from wild boar.

Classical swine fever virus (CSFV) strain WB82, isolated from a wild boar in 1982, induced a distinct cytopathic effect (CPE) in primary swine testicle cell culture and in most of the porcine cell lines. This strain of CSFV was found to be composed of two biotypes. cytopathogenic (cp) CSFV, as a minor population, and noncytopathogenic (noncp) CSFV, as a major population. The noncp CSFV (designated strain WB82/E+) was obtained by biological cloning, and it showed the exaltation of Newcastle disease virus phenomenon. In Northern blot analysis and RT-PCR assay, CSFV RNA with a subgenomic (sg) length was detected in addition to full-length viral RNA only in the cells in which a CPE had been revealed. These RNAs represent the genomes of typical defective interfering (DI) particles because of the strict dependence on a complementing helper virus and interference with replication of the helper virus. The sg RNA, which exhibits the genomes of the DI particles, lacked the nucleotides of the viral genomic region from Npro to NS2 (4764 bases). When extracted sg RNA was transfected to the cells infected with the WB82/E+ strain, a distinct CPE was observed. Interestingly, the CPE was observed in cells infected with other heterologous noncp CSFV ALD and GPE- strains by sg RNA transfection. The results suggested that these noncp CSFVs act as helper viruses for the replication of sg RNA (DI particles). It was also shown that the cytopathogenicity of strain WB82 is caused by apoptosis.

Animals↗
PubMed2000

Comparative immunohistopathology in pigs infected with highly virulent or less virulent strains of hog cholera virus.

Eight pigs were inoculated subcutaneously with a highly virulent hog cholera virus (HCV) strain ALD. The infected pigs developed severe illness and became moribund on postinoculation day (PID) 7 or PID 10. Histologic lesions were characterized by severe generalized vasculitis, necrosis of lymphocytes, and encephalitis. HCV antigen was detected in crypt tonsilar epithelial cells, macrophages, and reticular endothelial cells of lymphoid tissues. Antigen localization corresponded well with histologic lesions. Five pigs were inoculated with less virulent HCV Kanagawa/74 strain and were euthanatized on PID 30. All five infected pigs recovered from the illness but became stunted. They also had a slight follicular depletion of lymphocytes, histiocytic hyperplasia, and hematopoiesis in the spleen. Less virulent HCV antigen was observed in the tonsils, kidneys, pancreas, adrenal glands, and lungs. Although antigen localization was less associated with histologic lesions, immunoreactivity was stronger than that in the pigs infected with the ALD strain of HCV. An almost complete loss of B lymphocytes was recognized in pigs infected with the ALD strain and was correlated with follicular necrosis in lymphoid tissues. Loss of B lymphocytes was not prominent in the pigs infected with Kanagawa/74 strain. The number of CD4+ and CD8+ T lymphocytes was significantly higher than that in the noninfected control pigs.

Animals↗
PubMed1999

Induction of antibodies in mice by a recombinant baculovirus expressing pseudorabies virus glycoprotein B in mammalian cells.

The glycoprotein gB of pseudorabies virus (PrV) was expressed in various mammalian cells by a recombinant baculovirus carrying the PrV gB gene under the control of the CAG promoter. When the recombinant baculovirus was inoculated into the stable porcine kidney cell line CPK, expression of PrV gB was detected by immunofluorescent antibody analysis and a 155 kDa of protein, which has the same molecular mass as the native PrV gB, was detected by Western blotting. High levels of expression of PrV gB were observed in BHK-21, HmLu-1 and SK-H cell lines. Furthermore, anti-PrV gB-specific antibodies against PrV gB protein were detected by the enzyme-linked immunosorbent assay in mice inoculated the recombinant baculovirus. The recombinant baculovirus containing the PrV glycoprotein gB gene under the CAG promoter could be a candidate for a pseudorabies vaccine.

Animals↗
PubMed1999

Genetic heterogeneity of porcine and ruminant pestiviruses mainly isolated in Japan.

The genetic variability of porcine and ruminant pestiviruses was studied by comparative nucleotide sequence analysis of 73 isolates (42 porcine and 31 ruminant), including 65 Japanese isolates (35 porcine and 30 ruminant). The 5'-untranslated region (UTR) amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) was determined by direct sequencing and phylogenetic analysis was performed from the nucleotide sequence data. Most porcine isolates were divided into two major subgroups, classical swine fever virus (CSFV) subgroup 1 (CSFV-1, represented by Brecia strain) and subgroup 2 (CSFV-2, represented by Alfort strain). However, the Japanese Kanagawa/74, Okinawa/86, Okinawa/86-2 and Thai CBR/93 strains were the most distinct variants and these were assigned to another new disparate subgroup, CSFV-3 (represented by p97 strain). Most ruminant isolates were classified as the bovine viral diarrhoea virus (BVDV) genotype-I (BVDV-I) and subdivided into two subgroups, BVDV-Ia (represented by the NADL strain) and Ib (represented by the Osloss strain). Two bovine isolates (MS-1 and SY-89) and a contaminating strain (V/FLL) from an ovine cell line were classified as BVDV genotype-II (BVDV-II) on genetic characteristics. These data suggested that the detection and phylogenetic analysis of 5'-UTRs are useful for the rapid characterization of field isolates.

Animals↗
PubMed1998

Establishment and characterization of a porcine kidney cell line, FS-L3, which forms unique multicellular domes in serum-free culture.

A stable porcine kidney epithelial cell line, FS-L3, was established and maintained in Eagle's minimum essential medium containing 0.295% tryptose phosphate broth, 0.5% Bacto Peptone, and 10 mM N, N-Bis (2-hydroxyethyl)-2-aminoethanesulfonic acid without any serum. The mode of chromosomes is 37 to 38. The FS-L3 cells formed fluid-filled, multicellular, three-dimensional domes on a single monolayer. The number of domes increased markedly after further cultivation. The origin of this cell line was confirmed as porcine by hybridization using PRE-1, which can be detected as a specific sequence in the porcine genome. It was also found that FS-L3 cells were free from possible adventitious viruses and mycoplasmas.

Animals↗
PubMed1998

A new assay for classical swine fever virus based on cytopathogenicity in porcine kidney cell line FS-L3.

A new assay termed the dome disappearance method for classical swine fever virus (CSFV) using FS-L3 cells with serum-free culture medium was developed. The CSFV live vaccine GPE- strain grows well and shows a slight cytopathic effect (CPE) in FS-L3 cells. This CPE results in the disappearance of the unique fluid-filled multicellular domes on a single monolayer of FS-L3 cells. By using this phenomenon, dome disappearance, as a marker of infection, it was possible to determine the titers of CSFV and its neutralizing antibody. The virus titer determined by this method shows a good correlation with that determined by immunochemical and interference methods. Furthermore, the amount of neutralizing antibody measured by this method also correlated with that measured by the Exaltation of Newcastle Disease Virus (END) neutralizing method. The dome disappearance method developed in this experiment is a simple and safe procedure and has the great advantage that bovine serum, which may contain antibody against bovine viral diarrhea virus, is not necessary for the cultivation of FS-L3 cells.

Animals↗
PubMed1998

Establishment of a serum-free culture cell line, CPK-NS, which is useful for assays of classical swine fever virus.

A stable porcine kidney cell line, CPK-NS, was established and maintained in serum-free culture. A cytopathic effect (CPE) was observed clearly in CPK-NS cells infected with some classical swine fever virus (CSFV) strains which did not show the exaltation of Newcastle disease virus (END) phenomenon. Chromosome condensation and DNA fragmentation, a marker for apoptosis, were detected in cells infected with END phenomenon-negative CSFV strains. By using the CPE induced by infection with an END phenomenon-negative CSFV strain in CPK-NS cells, assays of CSFV were established. The virus titer determined in CPK-NS cells shows a high correlation with the usual peroxidase-linked assay, dome disappearance method and END method. Furthermore, the antibody titer by neutralizing test with CPK-NS cells also correlated with that measured by the usual neutralizing peroxidase-linked assay and dome disappearance method. These stable CPK-NS cells have the great advantage that a clear CPE was caused by infection with END phenomenon-negative CSFV strains and bovine serum is not necessary for cell culture and virus assays.

Animals↗
PubMed1998

Rare case of autoimmune hyperchylomicronemia during pregnancy.

A pregnant woman was found to have severe hypertriglyceridemia, fasting chylomicronemia, and low platelet count. The activities of serum lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) proved to be extremely low. The activities of the enzymes in normal plasma were completely inhibited by addition of the patient's plasma. We concluded that autoantibodies to lipases were responsible for this patient's hypertriglyceridemia.

Adult↗
PubMed1998

Retinal manifestations in mitochondrial diseases associated with mitochondrial DNA mutation.

PURPOSE: To scrutinize retinal involvement associated with distinct mitochondrial DNA (mtDNA) defects, we reviewed the records of a consecutive series of patients with various mitochondrial diseases. METHODS: Clinical, laboratory and mtDNA studies were performed in: five patients with Kearns-Sayre syndrome (KSS); six patients with chronic progressive external ophthalmoplegia (CPEO); three patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode (MELAS); three patients with myoclonic epilepsy and ragged-red fibers (MERRF); 20 patients with Leber's hereditary optic neuropathy (LHON); 30 patients with simple diabetes mellitus. RESULTS: All KSS patients with neurologic and cardiac symptoms associated with a deletion of mtDNA in muscle biopsy specimens showed widespread retinal pigmentary changes characterized by salt- and pepper-like appearance of the fundus. Three of six patients with CPEO, a mild variant of KSS, showed subtle defects at the level of retinal pigment epithelium of the posterior pole, although mtDNA deletion was similar to that in KSS. Of three patients with MELAS syndrome, one patient showed juvenile cataract and mild retinal pigmentary defect in the posterior pole. Of three patients with MERRF syndrome associated with a mtDNA mutation at nucleotide position (np) 8344, one patient showed mild pigment disorder in the posterior pole in addition to optic neuropathy. Two of 20 patients with LHON associated with a mtDNA mutation at np 11778 showed mild pigmentary defect in the macula together with typical optic neuropathy. In addition, two of 30 patients with isolated diabetes mellitus showed a mtDNA mutation at np 3243 (MELAS mutation), but they did not present with any other neurologic or multisystem disorder. CONCLUSION: The retina, in particular the retinal pigment epithelium, is highly vulnerable to be involved by mtDNA defect, and the retinopathy is phenotypically variable and frequently subclinical, depending to some extent on the type or site of mtDNA defect.

Adolescent↗