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Ichiro Kurane

Publications and source records attributed to Ichiro Kurane.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Evaluation of mouse brain-derived, inactivated Japanese encephalitis vaccine].

Japanese encephalitis (JE) is a serious encephalitis caused by JE virus. Approximately 20% of JE patients die and 50% patients recover with neuro-psychiatric sequelae. In Japan, the number of JE patients was over 1000 per year in 1960s; however, the number decreased dramatically and has been less than 10 since 1990. Ministry of Health, Labour and Welfare suspended the strong recommendation for vaccination with the mouse brain-derived JE vaccine, because of cases who developed acute disseminated encephalomyelitis (ADEM) after vaccination with JE vaccine. However, it has not been fully confirmed on scientific bases that ADEM was caused by mouse brain-derived JE vaccine. Tissue culture derived-JE vaccine is under development. It is expected that this new vaccine will come to the market soon and that the recommendation of universal vaccination with JE vaccine will be implemented at the earliest occasion.

Animals↗
PubMed2005

[West Nile fever/encephalitis as one of the arboviral infections].

West Nile virus maintains natural infection cycle between birds and mosquitoes. It has been known that about 200 species of birds are infected with West Nile virus and the virus is isolated from more than 40 species of mosquitoes. This suggests that West Nile virus has an ability to be transmitted by many species of mosquitoes and infect many kinds of animals. Approximately 20% of infected humans develop symptoms. West Nile fever, an acute febrile illness, is the main disease, and meningitis and encephalitis (meningoencephalitis) occasionally occur. Cases with flaccid paralysis or polyneuritis have been recently reported. Thus, West Nile virus causes multiple types of symptoms in humans. The endemic area has expanded in North America and Siberia. West Nile virus may enter Japan in the near future; therefore, we should keep paying attention to the endemic and epidemic situations in the world.

Animals↗
PubMed2005

Japanese encephalitis virus in meningitis patients, Japan.

Cerebrospinal fluid specimens from 57 patients diagnosed with meningitis were tested for Japanese encephalitis virus. Total RNA was extracted from the specimens and amplified. Two products had highest homology with Nakayama strain and 2 with Ishikawa strain. Results suggest that Japanese encephalitis virus causes some aseptic meningitis in Japan.

Child↗
PubMed2005

Immunological detection of severe acute respiratory syndrome coronavirus by monoclonal antibodies.

In order to establish immunological detection methods for severe acute respiratory syndrome coronavirus (SARS-CoV), we established monoclonal antibodies directed against structural components of the virus. B cell hybridomas were generated from mice that were hyper-immunized with inactivated SARS-CoV virion. By screening 2,880 generated hybridomas, we established three hybridoma clones that secreted antibodies specific for nucleocapsid protein (N) and 27 clones that secreted antibodies specific for spike protein (S). Among these, four S-protein specific antibodies had in vitro neutralization activity against SARS-CoV infection. These monoclonal antibodies enabled the immunological detection of SARS-CoV by immunofluorescence staining, Western blot or immunohistology. Furthermore, a combination of monoclonal antibodies with different specificities allowed the establishment of a highly sensitive antigen-capture sandwich ELISA system. These monoclonal antibodies would be a useful tool for rapid and specific diagnosis of SARS and also for possible antibody-based treatment of the disease.

Animals↗
PubMed2005

Detection of Japanese encephalitis (JE) virus-specific IgM in cerebrospinal fluid and serum samples from JE patients.

Detection of Japanese encephalitis virus (JEV)-specific IgM by IgM-capture enzymed-linked immunosorbent assay (IgM-capture ELISA) has been accepted as the standard for serological diagnosis. In the present study, we analyzed the time course of the positive rate of JEV-specific IgM in serum and cerebrospinal fluid (CSF) specimens from confirmed JE patients. Serum and CSF samples were obtained from 155 JE cases for diagnostic purposes at hospitals in Thailand from 2002 to 2004. The levels of specific IgM were assessed by IgM-capture ELISA in the 171 serum and 156 CSF samples. Anti-JEV IgM was detected in 26 of 44 serum samples collected on days 1-4 of the disease period, in 31 of 44 samples collected on days 5-8, in 23 of 26 samples collected on days 9-12, and in all the samples collected on day 13 or later. Specific IgM was detected in 60 of 66 CSF samples collected on days 1-4 of illness, and in all the CSF samples but one collected on day 7 or later. The results indicate that the detection of JEV-specific IgM in CSF by IgM-capture ELISA is a reliable laboratory diagnostic method for confirmation of JE throughout the disease period, while the detection of IgM in serum samples is a reliable method on day 9 or later.

Antibodies, Viral↗
PubMed2005

[Molecular epidemiology of Xinjiang hemorrhagic fever viruses].

BACKGROUND: To study the molecular biology of Xinjiang hemorrhagic fever (XHF) viruses, to explore its relationship with other Crimean-Congo hemorrhagic fever viruses, analyzing the epidemic origin and the tendency of geographic distribution of XHF. METHODS: The S partial segment from the patient and tick samples collected in 2001 and 2002 was tested by RT-PCR, the positive samples were sequenced directly. The nucleotide homology of S partial segment as well as the whole segments were analyzed and the phylogenetic tree of S and M gene segments was drawn by computer. RESULTS: All compared sequences of S partial segments from the patient and tick samples showed a high homology of nucleotide sequences. Phylogenetic tree divided all the analyzed viruses into three groups; Europe, African and Asian group. The Asian group can be divided further into another two branches: the middle Asian branch and the Chinese branch. All the Chinese isolates were clustered into one single group and was easy to be discriminated from the other isolates. The dividing of M segments seemed not completely related to the geographic origin of the viruses. CONCLUSION: M segment classification was not consistent to the geographic distribution of the viruses. S segments analysis showed the close relationship of genetic background between the patient isolates and the tick isolates. Besides, all the Chinese isolates have the common evolution route and the gene structure characteristics displayed the regional distribution pattern.

Animals↗
PubMed2005

[West Nile fever and West Nile encephalitis].

West Nile virus is a mosquito-borne flavivirus, and maintained in mosquito-bird cycle in nature. Humans are a dead-end host in West Nile virus infection. Symptoms are developed in approximately 20% of West Nile virus-infected humans. Encephalitis and meningitis are developed in about 1 out of 150 infected humans, especially in elderly populations. It has recently been reported that West Nile virus causes polio-like, acute flaccid paralysis and polyneuritis. These symptoms occur in patients without central nervous system symptoms as well as in those with encephalitis. Thus, West Nile virus causes various types of illness in humans. West Nile virus has not entered Japan yet. However, West Nile virus should be considered to be one of the causative agents for patient with a febrile illness, meningitis, encephalitis or acute flaccid paralysis who came back from West Nile endemic or epidemic areas of the world.

Encephalitis, Viral↗
PubMed2004

Tyrosine dephosphorylation of STAT3 in SARS coronavirus-infected Vero E6 cells.

Severe acute respiratory syndrome (SARS) has become a global public health emergency. p38 mitogen-activated protein kinase (MAPK) and its downstream targets are activated in SARS coronavirus (SARS-CoV)-infected Vero E6 cells and activation of p38 MAPK enhances the cytopathic effects of SARS-CoV infection. In addition, weak activation of Akt cannot prevent SARS-CoV infection-induced apoptosis in Vero E6 cells. In the present study, we demonstrated that signal transducer and activator of transcription (STAT) 3, which is constitutively phosphorylated at tyrosine (Tyr)-705 and slightly phosphorylated at serine (Ser)-727 in Vero E6 cells, was dephosphorylated at Tyr-705 on SARS-CoV infection. In addition to phosphorylation of p38 MAPK in virus-infected cells, other MAPKs, i.e., extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK), were phosphorylated. Although inhibitors of ERK1/2 and JNK (PD98059 and SP600125) had no effect on phosphorylation status of STAT3, inhibitors of p38 MAPK (SB203580 and SB202190) partially inhibited dephosphorylation of STAT3 at Tyr-705. Tyr-705-phosphorylated STAT3 was localized mainly in the nucleus in mock infected cells, whereas STAT3 disappeared from the nucleus in virus-infected cells. As STAT3 acts as an activator of transcription in the nucleus, these results suggest that STAT3 lacks its activity on transcription in SARS-CoV-infected Vero E6 cells.

Animals↗
PubMed2004

Importance of Akt signaling pathway for apoptosis in SARS-CoV-infected Vero E6 cells.

Severe acute respiratory syndrome (SARS) is an acute respiratory tract infectious disease that is associated with a new coronavirus (SARS-CoV). Our recent study indicated that SARS-CoV infection induces activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway and the p38 MAPK inhibitor partially inhibited its cytopathic effect in Vero E6 cells. The results of the present study indicated that before cell death, Akt, which is an inhibitor of apoptosis, was also activated in response to viral replication. Phosphorylation of a serine residue on Akt was detected at least 8 h postinfection (hpi), which declined after 18 hpi. Thus, the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is activated in virus-infected Vero E6 cells. However, a threonine residue was not phosphorylated. A downstream target of Akt, glycogen synthase kinase 3beta (GSK-3beta), was slightly phosphorylated, indicating that the level of activation of Akt was very low. PKCzeta, which is downstream of the PI3K pathway, was also phosphorylated in virus-infected cells. These results suggested that weak activation of Akt cannot prevent apoptosis induced by SARS-CoV infection in Vero E6 cells.

Animals↗
PubMed2004

Phosphorylation of p38 MAPK and its downstream targets in SARS coronavirus-infected cells.

Severe acute respiratory syndrome (SARS) has become a global public health emergency. Understanding the molecular mechanisms of SARS-induced cytopathic effects (CPEs) is a rational approach for the prevention of SARS, and an understanding of the cellular stress responses induced by viral infection is important for understanding the CPEs. Polyclonal antibodies, which recognized nucleocapsid (N) and membrane (M) proteins, detected viral N and M proteins in virus-infected Vero E6 cells at least 6 and 12 h post-infection (h.p.i.), respectively. Furthermore, detection of DNA ladder and cleaved caspase-3 in the virus-infected cells at 24h.p.i. indicated that SARS-CoV infection induced apoptotic cell death. Phosphorylation of p38 MAPK was significantly up-regulated at 18 h.p.i. in SARS-CoV-infected cells. The downstream targets of p38 MAPK, MAPKAPK-2, HSP-27, CREB, and eIF4E were phosphorylated in virus-infected cells. The p38 MAPK inhibitor, SB203580, inhibited effectively phosphorylation of HSP-27, CREB, and eIF4E in SARS-CoV-infected cells. However, viral protein synthesis was not affected by treatment of SB203580.

Activating Transcription Factor 1↗
PubMed2004

Generation and characterization of P gene-deficient rabies virus.

Rabies virus (RV) deficient in the P gene was generated by reverse genetics from cDNA of HEP-Flury strain lacking the entire P gene. The defective virus was propagated and amplified by rescue of virus, using a cell line that complemented the functions of the deficient gene. The P gene-deficient (def-P) virus replicated its genome and produced progeny viruses in the cell lines that constitutively expressed the P protein, although it grew at a slightly retarded rate compared to the parental strain. In contrast, no progeny virus was produced in the infected host when the def-P virus-infected cells that did not express the P protein. However, we found that the def-P virus had the ability to perform primary transcription (by the virion-associated polymerase) in the infected host without de novo P protein synthesis. The def-P virus was apathogenic in adult and suckling mice, even when inoculated intracranially. Inoculation of def-P virus in mice induced high levels of virus-neutralizing antibody (VNA) and conferred protective immunity against a lethal rabies infection. These results demonstrate the potential utility of gene-deficient virus as a novel live attenuated rabies vaccine.

Animals↗
PubMed2004

Analysis of specific IgM responses in secondary dengue virus infections: levels and positive rates in comparison with primary infections.

BACKGROUND: Dengue viruses are a serious cause of illness in tropical and subtropical areas of the world. Laboratory diagnosis is essential for confirmation of dengue virus infections. Detection of specific IgM by IgM-capture enzymed-linked immunoassay (ELISA) has been widely used as a main serological diagnostic technique. OBJECTIVES: The levels of specific IgM in secondary dengue virus infections were compared with those in primary infections. STUDY DESIGN: A total of 1780 samples collected from 924 confirmed dengue cases were tested for anti-dengue IgM by IgM-capture ELISA. RESULTS AND CONCLUSIONS: Specific IgM was detected in all the cases with primary dengue virus infection on disease day 9 or later. However, specific IgM cannot be detected in 28% (204/716) of the cases in secondary infections. The average titers of IgM were higher in primary infections than in secondary infections. The results confirmed that IgM detection is a reliable serological diagnostic test in primary dengue virus infections. Although IgM detection is also a useful test, other serological diagnostic tests or tests for dengue virus detection are necessary for confirmation of all the secondary dengue virus infections.

Acute Disease↗
PubMed2004

In vitro assessment of human endothelial cell permeability: effects of inflammatory cytokines and dengue virus infection.

Electrical resistance across human umbilical vein endothelial cells (HUVECs) was measured using an electrical cell sensor system. The transendothelial electrical resistance (TEER) value was used to estimate the permeability through endothelial cells in vitro. Decrease in the TEER value was associated with increase in the passage of albumin through endothelial cells in the albumin permeability assay. The effects of cytokines and dengue virus infection on the permeability of HUVECs were examined by measuring the TEER value. Tumor necrosis factor alpha (TNF-alpha) at 1 and 0.1 microg/ml decreased the TEER value, but TNF-alpha at lower dose did not. Interferon-gamma (IFN-gamma) at 1 microg/ml also decreased the TEER value. In contrast, interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10) or interferon-beta (IFN-beta) did not decrease the TEER value. The decrease in the TEER value was associated with the morphological changes of HUVECs. Dengue virus infection at a multiplicities of infection (m.o.i.) of 5 pfu/cell decreased the TEER value. Infection at an m.o.i. of 0.5 pfu/cell did not decrease the TEER value; however, addition of 0.01 microg/ml of TNF-alpha to these infected endothelial cells decreased the TEER value. The results suggest that TNF-alpha and dengue virus infection decrease synergistically the TEER value of endothelial cells. The TEER method is easy, reliable and can be applicable to further analysis of the increase in the permeability of endothelial cells in vitro induced by inflammatory cytokines and dengue virus infection.

Cell Membrane Permeability↗
PubMed2004

Rabies virus stimulates nitric oxide production and CXC chemokine ligand 10 expression in macrophages through activation of extracellular signal-regulated kinases 1 and 2.

Macrophages represent an essential part of innate immunity, and the viral infection of macrophages results in the release of multiple proinflammatory mediators, such as nitric oxide (NO), cytokines, and chemokines. This study was undertaken to define the molecular mechanism of macrophage activation in response to rabies virus (RV) infection. In RAW264 murine macrophage cells, a well-characterized macrophage model, RV replication was strictly restricted, whereas cell proliferation was significantly enhanced upon RV inoculation. Transcriptional analyses for the expression of inducible forms of NO synthase (iNOS), cytokines, and chemokines revealed that RV virions potentiate the gene expression of iNOS and CXC chemokine ligand 10 (CXCL10), a major chemoattractant of T helper cell type 1. However, RV stimulation had little or no effect on the expression profiles of proinflammatory cytokines and other types of chemokines. In macrophages stimulated with UV-inactivated RV virions, as well as infectious viruses, the phosphorylation of extracellular signal-regulated kinase (ERK) 1 and 2, members of the mitogen-activated protein kinase family, was significantly induced. Specific inhibitors of MAPK/ERK kinase reduced the RV-induced production of NO and CXCL10. Furthermore, the RV-induced activation of the ERK1/2 pathway was severely impaired by the neutralization of the endosomal and lysosomal pH environment with lysosomotropic agents, indicating that endocytosis is a key step leading to the activation of ERK1/2 signaling. Taken together, these results suggest that the ERK1/2-mediated signaling pathway plays a cardinal role in the selective activation of macrophages in response to RV virions, thereby regulating cellular functions during virus infection.

Animals↗
PubMed2004

Genetic characterization of rabies viruses isolated from frugivorous bat (Artibeus spp.) in Brazil.

In Latin America, rabies cases related to frugivorous bats have been reported since 1930's. Recently, two viruses isolated from Artibeus lituratus were proved to be vampire bat variants by monoclonal antibodies panels [2], but their genetic information is not well known. In this report, four rabies viruses were isolated from frugivorous bats (Artibeus spp.) in Brazil and their nucleoprotein gene sequences were determined. These isolates were found to be genotype 1 of lyssavirus and showed the maximum nucleotide sequence homology of 97.6-99.4% with vampire bat-related viruses in Brazil [6]. These results indicate that the Brazilian frugivorous bat rabies viruses in this study are closely related to vampire bat-related viruses that play a main role in rabies virus transmission to livestock in Brazil.

Animals↗