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Timo Otonkoski - One of the best experts on this subject based on the ideXlab platform.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus induced damage to human pancreatic beta cells
The Journal of Clinical Endocrinology and Metabolism, 2000Co-Authors: Merja Roivainen, Suvi Rasilainen, Petri Ylipaasto, Decio L Eizirik, Tapani Hovi, Riikka Nissinen, J Ustinov, Luc Bouwens, Timo OtonkoskiAbstract:Enteroviruses may be involved in the pathogenesis of insulin-dependent diabetes mellitus, either through direct β-cell infection or as triggers of autoimmunity. In the present study we investigated the patterns of infection in adult human islet cell preparations (consisting of 56 ± 14% β-cells) by several Coxsackieviruses. The cells were infected with prototype strains of Coxsackievirus B (CBV) 3, 4, and 5 as well as Coxsackievirus A9 (CAV-9). The previously characterized diabetogenic strain of Coxsackievirus B4 (CBV-4-E2) was used as a reference. All viruses replicated well in β-cells, but only CBVs caused cell death. One week after infection, the insulin response of the β-cells to glucose or glucose plus theophyline was most severely impaired by CBV-3 and CBV-5 infections. CBV-4 also caused significant functional impairment, whereas CAV-9-infected cells responded like uninfected controls. After 2 days of infection, about 40% of CBV-5-infected cells had undergone morphological changes characteristic of p...
Merja Roivainen - One of the best experts on this subject based on the ideXlab platform.
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Differential cell autonomous responses determine the outcome of Coxsackievirus infections in murine pancreatic α and β cells.
eLife, 2015Co-Authors: Laura Marroquí, Fabio Arturo Grieco, Miguel Lopes, Reinaldo Sousa Dos Santos, Anne Op De Beeck, Sarah J Richardson, Merja Roivainen, Noel G. Morgan, Decio L EizirikAbstract:Type 1 diabetes is caused by a person's immune system attacking the cells in their pancreas that produce insulin. This eventually kills off so many of these cells—known as beta cells—that the pancreas is unable to make enough insulin. As a result, individuals with type 1 diabetes must inject insulin to help their bodies process sugars. One of the mysteries of type 1 diabetes is why the beta cells in the pancreas are killed by the immune system while neighboring alpha cells, which produce the hormone glucagon, are spared. Scientists suspect a combination of genetic and environmental factors contributes to type 1 diabetes. Certain viruses, including one called Coxsackievirus, appear to trigger type 1 diabetes in susceptible individuals. Other factors may also make these individuals more likely to develop the disease. For example, they may ‘express’ genes that are thought to increase the risk of type 1 diabetes, many of which control how the immune system responds to viral infections. These genes may make susceptible individuals experience excessive inflammation, because inflammation is what ultimately kills off the beta cells. Now, Marroqui, Lopes, dos Santos et al. provide evidence that suggests why the alpha cells are spared the immune onslaught in type 1 diabetes. In initial experiments, clusters of cells—known as islets—from the human pancreas were either exposed to small proteins that cause inflammation or infected with the Coxsakievirus. Both events caused a similar increase in the expression of particular immune response genes in the islets. This indicates that these islet cells are able to react to the virus and trigger a first line of defense, which will be further boosted when the immune system is subsequently called into action. Islets contain both alpha and beta cells, and so further experiments on alpha and beta cells from rats investigated whether the two cell types respond differently when infected by the Coxsakievirus. The results revealed that alpha cells boost the expression of the genes needed to clear the virus to a greater extent than the beta cells, and so respond more efficiently to the virus. Therefore, an infection is more likely to establish itself in the beta cells and consequently trigger inflammation and the immune system's attack on the cells. These observations explain one of the puzzling questions in the diabetes field and reinforce the possibility that a long-standing viral infection in beta cells—which seem to have a limited capacity to clear viral infections—may be one of the mechanisms leading to progressive beta cell destruction in type 1 diabetes. This knowledge will help in the search for ways to protect beta cells against both viral infections and the consequent immune assault.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus induced damage to human pancreatic beta cells
The Journal of Clinical Endocrinology and Metabolism, 2000Co-Authors: Merja Roivainen, Suvi Rasilainen, Petri Ylipaasto, Decio L Eizirik, Tapani Hovi, Riikka Nissinen, J Ustinov, Luc Bouwens, Timo OtonkoskiAbstract:Enteroviruses may be involved in the pathogenesis of insulin-dependent diabetes mellitus, either through direct β-cell infection or as triggers of autoimmunity. In the present study we investigated the patterns of infection in adult human islet cell preparations (consisting of 56 ± 14% β-cells) by several Coxsackieviruses. The cells were infected with prototype strains of Coxsackievirus B (CBV) 3, 4, and 5 as well as Coxsackievirus A9 (CAV-9). The previously characterized diabetogenic strain of Coxsackievirus B4 (CBV-4-E2) was used as a reference. All viruses replicated well in β-cells, but only CBVs caused cell death. One week after infection, the insulin response of the β-cells to glucose or glucose plus theophyline was most severely impaired by CBV-3 and CBV-5 infections. CBV-4 also caused significant functional impairment, whereas CAV-9-infected cells responded like uninfected controls. After 2 days of infection, about 40% of CBV-5-infected cells had undergone morphological changes characteristic of p...
Suvi Rasilainen - One of the best experts on this subject based on the ideXlab platform.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus induced damage to human pancreatic beta cells
The Journal of Clinical Endocrinology and Metabolism, 2000Co-Authors: Merja Roivainen, Suvi Rasilainen, Petri Ylipaasto, Decio L Eizirik, Tapani Hovi, Riikka Nissinen, J Ustinov, Luc Bouwens, Timo OtonkoskiAbstract:Enteroviruses may be involved in the pathogenesis of insulin-dependent diabetes mellitus, either through direct β-cell infection or as triggers of autoimmunity. In the present study we investigated the patterns of infection in adult human islet cell preparations (consisting of 56 ± 14% β-cells) by several Coxsackieviruses. The cells were infected with prototype strains of Coxsackievirus B (CBV) 3, 4, and 5 as well as Coxsackievirus A9 (CAV-9). The previously characterized diabetogenic strain of Coxsackievirus B4 (CBV-4-E2) was used as a reference. All viruses replicated well in β-cells, but only CBVs caused cell death. One week after infection, the insulin response of the β-cells to glucose or glucose plus theophyline was most severely impaired by CBV-3 and CBV-5 infections. CBV-4 also caused significant functional impairment, whereas CAV-9-infected cells responded like uninfected controls. After 2 days of infection, about 40% of CBV-5-infected cells had undergone morphological changes characteristic of p...
Yong Zhang - One of the best experts on this subject based on the ideXlab platform.
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Additional file 1: of Two Coxsackievirus B3 outbreaks associated with hand, foot, and mouth disease in China and the evolutionary history worldwide
2019Co-Authors: Zhenzhi Han, Jianxing Wang, Yong Zhang, Keqiang Huang, Huifang Tian, Yang Song, Qian Yang, Dongmei Yan, Shuangli Zhu, Mingxiao YaoAbstract:Figure S1. The result of date-randomization tests (DRTs). The temporal signal of CV-B3 datasets was tested using the Tip Dating Beast package. Based on 20 random replicates of the sampling dates produced by this package and the real datasets, the CV-B3 datasets are assured to have sufficient temporal signals for next assessment of evolutionary timescale. Table S1. The information of 236 Coxsackievirus B3 (CV-B3) strains used in this analysis, including 25 isolates first reported in this study. Table S2. Evolutionary characteristics of Coxsackievirus B3 (CV-B3) groups based on the entire VP1 gene. (DOCX 165 kb
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seroprevalence of enterovirus a71 and Coxsackievirus a16 in healthy people in shandong province china
PLOS ONE, 2016Co-Authors: Jianxing Wang, Xianjun Wang, Wenbo Xu, Jing Wang, Yong Zhang, Shujun DingAbstract:BACKGROUND: Hand, foot, and mouth disease has become very common in mainland of China in recent years, and enterovirus A71 and Coxsackievirus A16 are its major etiologic factors. Here we investigated the seroprevalence of enterovirus A71 and Coxsackievirus A16 based on a large group of healthy individuals in Shandong province, China. METHODS: A total of 1378 healthy individuals were tested for serum neutralizing antibodies against enterovirus A71 and Coxsackievirus A16 using a micro neutralization test. RESULTS: The overall seroprevalence of enterovirus A71 neutralizing antibodies was 74.75%. It increased significantly from 48.84% in children aged 0-1 years old to 88.64% in those aged 20-29 years (p 40 years old with a significant gender-specific difference (p 40 years without a gender-specific difference. Nearly 50% of the children <1 year were susceptible to enterovirus A71 infection versus 40% to Coxsackievirus A16 infection. Sample collection time and place also played a role in the enterovirus A71 and Coxsackievirus A16 positive rates. The overall rates in January were significantly lower than those in April and August (p < 0.01); enterovirus A71 positive rates in Jinan city (capital city of Shandong province) were lower than those in Jining city and Zibo city (p < 0.05); and oxsackievirus A16 positive rates in Jining city were significantly higher than those in Jinan city and Zibo city (p < 0.01). CONCLUSION: There were significant differences among age groups, locations, and time points in the seroprevalence rates of enterovirus A71 and Coxsackievirus A16 neutralizing antibodies in healthy people in Shandong province.
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evaluation of a direct reverse transcription loop mediated isothermal amplification method without rna extraction for the detection of human enterovirus 71 subgenotype c4 in nasopharyngeal swab specimens
PLOS ONE, 2012Co-Authors: Kai Nie, Yong Zhang, Le Luo, Yun Xie, Mengjie Yang, Yi Zhang, Hongwei ShenAbstract:Human enterovirus 71 (EV71) is the major causative agent of hand, foot, and mouth disease (HFMD) worldwide and has been associated with neurological complications which resulted in fatalities during recent outbreak in Asia pacific region. A direct reverse transcription loop-mediated isothermal amplification (direct RT-LAMP) assay using heat-treated samples without RNA extraction was developed and evaluated for the detection of EV71 subgenotype C4 in nasopharyngeal swab specimens. The analytical sensitivity and specificity of the direct RT-LAMP assay were examined. The detection limit of the direct RT-LAMP assays was 1.6 of a 50% tissue culture infective dose (TCID50) per reaction and no cross-reaction was observed with control viruses including Cosackievirus A (CVA) viruses (CVA2,4,5,7,9,10,14,16, and 24), Coxsackievirus B (CVB) viruses (CVB1,2,3,4, and 5) or ECHO viruses (ECHO3,6,11, and 19). The direct RT-LAMP assay was evaluated and compared to both RT-LAMP and quantitative real-time PCR (qRT-PCR) in detecting EV71 infection with 145 nasopharyngeal swab specimens. The clinical performance demonstrated the sensitivity and specificity of direct RT-LAMP was reported to be 90.3% and 100% respectively, compared to RT-LAMP, and 86.83% and 100% respectively, compared to qRT-PCR. These data demonstrated that the direct RT-LAMP assay can potentially be developed for the point of care screening of EV71 infection in China.
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visual detection of human enterovirus 71 subgenotype c4 and Coxsackievirus a16 by reverse transcription loop mediated isothermal amplification with the hydroxynaphthol blue dye
Journal of Virological Methods, 2011Co-Authors: Yong Zhang, Mengjie Yang, Xiumei Hu, Miao Wang, Wenbo XuAbstract:Abstract A sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for rapid visual detection of human enterovirus 71 subgenotype C4 (EV71-C4) and Coxsackievirus A16 (CVA16) infection, respectively. The reaction was performed in one step in a single tube at 65 °C for 60 min with the addition of the hydroxynaphthol blue (HNB) dye prior to amplification. The detection limits of the RT-LAMP assay were 0.33 and 1.58 of a 50% tissue culture infective dose (TCID50) per reaction based on 10-fold dilutions of a titrated EV71 or CVA16 strain, respectively. No cross-reaction was observed with Coxsackievirus A (CVA) viruses (CVA2, 4, 5, 7, 9, 10, 14, and 24), Coxsackievirus B (CVB) viruses (CVB1,2,3,4, and 5) or ECHO viruses (ECHO3, 6, 11, and 19). The assay was further evaluated with 47 clinical stool specimens diagnosed previously with EV71, CVA16 or other human enterovirus infections. Virus isolates from stool samples were confirmed by virus neutralization testing and sequencing. RT-LAMP with HNB dye was demonstrated to be a sensitive and cost-effective assay for rapid visual detection of human EV71-C4 and CVA16.
Tapani Hovi - One of the best experts on this subject based on the ideXlab platform.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus b5 mediated β cell death depend on the multiplicity of infection
Journal of Medical Virology, 2004Co-Authors: Suvi Rasilainen, Risto Lapatto, Merja Roivainen, Petri Ylipaasto, Tapani Hovi, Timo OtonkoskiAbstract:Coxsackievirus infections may trigger and accelerate pancreatic β-cell death, leading to type I diabetes. Unrestricted Coxsackievirus B5 replication in cultured β-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of β-cell death during high versus low multiplicity of Coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with Coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of γ-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of β-cell death after low multiplicity of Coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of Coxsackievirus B5 infection induced β-cell death depend on the MOI. J. Med. Virol. 72:586–596, 2004. © 2004 Wiley-Liss, Inc.
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mechanisms of Coxsackievirus induced damage to human pancreatic beta cells
The Journal of Clinical Endocrinology and Metabolism, 2000Co-Authors: Merja Roivainen, Suvi Rasilainen, Petri Ylipaasto, Decio L Eizirik, Tapani Hovi, Riikka Nissinen, J Ustinov, Luc Bouwens, Timo OtonkoskiAbstract:Enteroviruses may be involved in the pathogenesis of insulin-dependent diabetes mellitus, either through direct β-cell infection or as triggers of autoimmunity. In the present study we investigated the patterns of infection in adult human islet cell preparations (consisting of 56 ± 14% β-cells) by several Coxsackieviruses. The cells were infected with prototype strains of Coxsackievirus B (CBV) 3, 4, and 5 as well as Coxsackievirus A9 (CAV-9). The previously characterized diabetogenic strain of Coxsackievirus B4 (CBV-4-E2) was used as a reference. All viruses replicated well in β-cells, but only CBVs caused cell death. One week after infection, the insulin response of the β-cells to glucose or glucose plus theophyline was most severely impaired by CBV-3 and CBV-5 infections. CBV-4 also caused significant functional impairment, whereas CAV-9-infected cells responded like uninfected controls. After 2 days of infection, about 40% of CBV-5-infected cells had undergone morphological changes characteristic of p...
