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11.
Lydia Tan Frank E. J. Coenjaerts Lieselot Houspie Marco C. Viveen Grada M. van Bleek Emmanuel J. H. J. Wiertz Darren P. Martin Philippe Lemey 《Journal of virology》2013,87(14):8213-8226
Genomic variation and related evolutionary dynamics of human respiratory syncytial virus (RSV), a common causative agent of severe lower respiratory tract infections, may affect its transmission behavior. RSV evolutionary patterns are likely to be influenced by a precarious interplay between selection favoring variants with higher replicative fitness and variants that evade host immune responses. Studying RSV genetic variation can reveal both the genes and the individual codons within these genes that are most crucial for RSV survival. In this study, we conducted genetic diversity and evolutionary rate analyses on 36 RSV subgroup B (RSV-B) whole-genome sequences. The attachment protein, G, was the most variable protein; accordingly, the G gene had a higher substitution rate than other RSV-B genes. Overall, less genetic variability was found among the available RSV-B genome sequences than among RSV-A genome sequences in a comparable sample. The mean substitution rates of the two subgroups were, however, similar (for subgroup A, 6.47 × 10−4 substitutions/site/year [95% credible interval {CI 95%}, 5.56 × 10−4 to 7.38 × 10−4]; for subgroup B, 7.76 × 10−4 substitutions/site/year [CI 95%, 6.89 × 10−4 to 8.58 × 10−4]), with the time to their most recent common ancestors (TMRCAs) being much lower for RSV-B (19 years) than for RSV-A (46.8 years). The more recent RSV-B TMRCA is apparently the result of a genetic bottleneck that, over longer time scales, is still compatible with neutral population dynamics. Whereas the immunogenic G protein seems to require high substitution rates to ensure immune evasion, strong purifying selection in conserved proteins such as the fusion protein and nucleocapsid protein is likely essential to preserve RSV viability. 相似文献
12.
Lieselot Houspie Sarah De Coster Els Keyaerts Phouthalack Narongsack Rikka De Roy Ive Talboom Maura Sisk Piet Maes Jannick Verbeeck Marc Van Ranst 《Virology journal》2011,8(1):1-7
Background
Human enterovirus 71 (EV71) has emerged as a significant cause of acute encephalitis and deaths in young children. The clinical manifestations caused by EV71 varied from mild hand, foot and mouth disease to severe neurological complications and deaths, but its pathogenesis remains elusive. Antibody dependent enhancement (ADE) infection has been reported in various viruses and has been shown to contribute to disease severity.Results
In this study, the presence of sub-neutralizing antibody was demonstrated to enhance EV71 infection in THP-1 cells and increase the mortality of EV71 infection in a suckling mouse model. Further, a secondary infection model was established to characterize the correlation between ADE and disease severity, and primary asymptomatic EV71 infection was shown to increase the mortality of the secondary EV71 infection in suckling mice.Conclusions
Together, these in vitro and in vivo experiments strongly supported the hypothesis of ADE infection of EV71. The present findings indicate ADE might contribute to the pathogenesis of severe EV71 infection, and raise practical issues of vaccine development and antibody-based therapy. 相似文献13.
Liesbeth?Van WesenbeeckEmail author Hanne?Meeuws David?D’Haese Gabriela?Ispas Lieselot?Houspie Marc?Van Ranst Lieven?J?Stuyver 《Virology journal》2014,11(1):233
Background
With the clinical development of several antiviral intervention strategies for influenza, it becomes crucial to explore viral load shedding in the nasal cavity as a biomarker for treatment success, but also to explore sampling strategies for sensible and reliable virus collection.Findings
In this study, 244 patients suffering from Influenza like Illness and/or acute respiratory tract infection were enrolled. Sampling was done using mid-turbinate flocked swabs and two swabs per patient were collected (one swab per nostril). The influenza A viral loads of two mid-turbinate flocked swabs (one for each nostril) per patient were compared and we have also assessed whether normalization for human cellular DNA in the swabs could be useful. The Influenza mid-turbinate nasal swab testing resulted in considerable sampling variability that could not be normalized against co-isolated human cellular DNA.Conclusions
Influenza viral load monitoring in nasal swabs could be very valuable as virological endpoints in clinical trials to monitor treatment efficacy, in analogy to HIV, HBV & HCV viral load monitoring. However, the differences between left and right nostrils, as observed in this study, highlight the importance of proper sampling and the need for standardized sampling procedures.14.
Lydia Tan Philippe Lemey Lieselot Houspie Marco C. Viveen Nicolaas J. G. Jansen Anton M. van Loon Emmanuel Wiertz Grada M. van Bleek Darren P. Martin Frank E. Coenjaerts 《PloS one》2012,7(12)
Human respiratory syncytial virus (RSV) is an important cause of severe lower respiratory tract infections in infants and the elderly. In the vast majority of cases, however, RSV infections run mild and symptoms resemble those of a common cold. The immunological, clinical, and epidemiological profile of severe RSV infections suggests a disease caused by a virus with typical seasonal transmission behavior, lacking clear-cut virulence factors, but instead causing disease by modifying the host’s immune response in a way that stimulates pathogenesis. Yet, the interplay between RSV-evoked immune responses and epidemic behavior, and how this affects the genomic evolutionary dynamics of the virus, remains poorly understood. Here, we present a comprehensive collection of 33 novel RSV subgroup A genomes from strains sampled over the last decade, and provide the first measurement of RSV-A genomic diversity through time in a phylodynamic framework. In addition, we map amino acid substitutions per protein to determine mutational hotspots in specific domains. Using Bayesian genealogical inference, we estimated the genomic evolutionary rate to be 6.47×10−4 (credible interval: 5.56×10−4, 7.38×10−4) substitutions/site/year, considerably slower than previous estimates based on G gene sequences only. The G gene is however marked by elevated substitution rates compared to other RSV genes, which can be attributed to relaxed selective constraints. In line with this, site-specific selection analyses identify the G gene as the major target of diversifying selection. Importantly, statistical analysis demonstrates that the immune driven positive selection does not leave a measurable imprint on the genome phylogeny, implying that RSV lineage replacement mainly follows nonselective epidemiological processes. The roughly 50 years of RSV-A genomic evolution are characterized by a constant population size through time and general co-circulation of lineages over many epidemic seasons – a conclusion that might be taken into account when developing future therapeutic and preventive strategies. 相似文献
15.
Cerebral fat embolism induced by facial fat injection 总被引:2,自引:0,他引:2
Thaunat O Thaler F Loirat P Decroix JP Boulin A 《Plastic and reconstructive surgery》2004,113(7):2235-2236
16.
Bruno Verschuere Geert Crombez Lieselot Smolders Armand De Clercq 《Applied psychophysiology and biofeedback》2009,34(3):237-244
Using physiological measures, concealed information can be validly assessed. Orienting theory has been proposed to account
for concealed information testing. As orienting is characterized by heart rate deceleration, one would expect this type of
heart rate response to concealed information. However, with some exceptions, an initial heart rate acceleration to concealed
information is typically observed. In the present paper, we examine the role of verbalization to explain the mixed pattern
of heart rate changes. Using a within-subjects design, 30 participants were asked to either remain silent or to give an overt
verbal response (“yes”/”no”) to concealed autobiographical and control information. The results indicate that verbalization
accounts for the initial heart rate acceleration. In line with the orienting theory, initial heart rate deceleration is observed
when participants remained silent.
Bruno Verschuere is a postdoctoral fellow of the Scientific Research Foundation (FWO). 相似文献