Fractures of the talus are rare in children.A high index of suspicion is needed to avoid missing such an injury,which is not an uncommon occurrence especially with undisplaced fractures.We present an unusual case of a...Fractures of the talus are rare in children.A high index of suspicion is needed to avoid missing such an injury,which is not an uncommon occurrence especially with undisplaced fractures.We present an unusual case of an undisplaced talar neck fracture in a five-year-old child leading to a delayed presentation of a symptomatic osteochondral loose body in the ankle joint.To our knowledge there are no reports in the literature of osteochondral loose bodies occurring in conjunction with an associated undisplaced talar neck fracture in either children or adults.The loose body was removed using anterior ankle arthroscopy.The child had an uneventful post operative recovery and regained full range of movement and function of his ankle joint and was discharged at one year follow-up.We aim to highlight the need to have a low threshold to further evaluate symptomatic children after fracture healing of an undisplaced talar neck fracture for a possible associated loose bodyin the ankle joint.展开更多
Rabies is a disease caused following infection of the brainby the rabies virus(RABV). The principle mechanism of transmission is through a bite wound. The virus infects peripheral nerves and moves to the central nervo...Rabies is a disease caused following infection of the brainby the rabies virus(RABV). The principle mechanism of transmission is through a bite wound. The virus infects peripheral nerves and moves to the central nervous system(CNS). There appears to be little involvement of other organ systems and little detectable immune stimulation prior to infection of the CNS. This failure of the mammalian immune system to respond to rabies virus infection leads, in the overwhelming majority of cases, to death of the host. To some extent, this failure is likely due to the exclusive replication of RABV in neurons and the limited ability to generate, sufficiently rapidly, an anti-viral antibody response in situ. This is reflected in the ability of post-exposure vaccination, when given early after infection, to prevent disease. The lack of immune stimulation during RABV infection preceding neural invasion is the Achilles heel of the immune response. Whilst many viruses infect the brain, causing encephalitis and neuronal deficit, none are as consistently fatal to the host as RABV. This is in part due to prior replication of many viruses in peripheral, non-neural tissue by other viruses that allows timely activation of the immune response before the host is overwhelmed. Our current understanding of the correlates of protection for rabies suggests that it is the action of neutralising antibodies that prevent infection and control spread of RABV. Furthermore, it tells us that the induction of immunity can protect and understanding how and why this happens is critical to controlling infection. However, the paradigm of antibody development suggests that antigen presentation overwhelmingly occurs in lymphoid tissue(germinal and non-germinal centres) and these are external to the CNS. In addition, the blood-brain-barrier may provide a block to the delivery of immune effectors(antibodies/plasma B-cells) entering where they are needed. Alternatively, there may be insufficient antigen exposure after natural infection to mount an effective response or the virus actively suppresses immune function. To improve our ability to treat this fatal infection it is imperative to understand how immunity to RABV develops and functions so that parameters of protectionare better defined.展开更多
Aims Variation in precipitation strongly influences plant growth,species distributions and genetic diversity.intraspecific variation in pheno-typic plasticity,the ability of a genotype to alter its growth,morphol-ogy ...Aims Variation in precipitation strongly influences plant growth,species distributions and genetic diversity.intraspecific variation in pheno-typic plasticity,the ability of a genotype to alter its growth,morphol-ogy or physiology in response to the environment,could influence species responses to changing precipitation and climate change.Despite this,the patterns and mechanisms of intraspecific varia-tion in plasticity to variable precipitation,and the degree to which genotype responses to precipitation are influenced by variation in edaphic conditions,remain poorly understood.Thus,we determined whether genotypes of a widespread C_(4) grass(Panicum virgatum L.,switchgrass)varied in aboveground productivity in response to changes in precipitation,and if site edaphic conditions modified genotype aboveground productivity responses to precipitation.We also determined if genotype productivity responses to precipitation are related to plasticity in underlying growth and phenological traits.Methods Nine P.virgatum genotypes originating from an aridity gradient were grown under four treatments spanning the 10th to the 90th percentiles of annual precipitation at two sites in central Texas:one site with deep,fine-textured soils and another site with shallow,coarse-textured soils.We measured volumetric soil water content(VWC),aboveground net primary productivity(ANPP),tiller pro-duction(tiller number),average tiller mass,canopy height,leaf area index(LAi)and flowering time on all plants at both sites and examined genotype responses to changes in precipitation.Important Findings Across precipitation treatments,VWC was 39%lower and more variable at the site with shallow,coarse-textured soils compared to the site with deep,fine-textured soils.ANPP averaged across genotypes and precipita-tion treatments was also 103%higher at the site with deep,fine-textured soils relative to the site with shallow,coarse-textured soils,indicating substantial differences in site water limitation.Where site water limi-tation was higher,ANPP of most genotypes increased with increasing precipitation.Where site water limitation was less,genotypes expressed variable plasticity in response to precipitation,from no change to almost a 5-fold increase in ANPP with increasing precipitation.Genotype ANPP increased with greater tiller mass,LAi and later flowering time at both sites,but not with tiller number at either site.Genotype ANPP plasticity increased with genotype tiller mass and LAi plasticity at the site with deep,fine-textured soils,and only with genotype tiller mass plasticity at the site with shallow,coarse-textured soils.Thus,variation in genotype ANPP plasticity was explained primarily by variation in tiller and leaf growth.Genotype ANPP plasticity was not associated with temperature or aridity at the genotype’s origin.Edaphic factors such as soil depth and texture may alter genotype ANPP responses to precipitation,and the underlying growth traits contributing to the ANPP response.Thus,edaphic factors may contribute to spatial variation in genotype performance and success under altered precipitation.展开更多
文摘Fractures of the talus are rare in children.A high index of suspicion is needed to avoid missing such an injury,which is not an uncommon occurrence especially with undisplaced fractures.We present an unusual case of an undisplaced talar neck fracture in a five-year-old child leading to a delayed presentation of a symptomatic osteochondral loose body in the ankle joint.To our knowledge there are no reports in the literature of osteochondral loose bodies occurring in conjunction with an associated undisplaced talar neck fracture in either children or adults.The loose body was removed using anterior ankle arthroscopy.The child had an uneventful post operative recovery and regained full range of movement and function of his ankle joint and was discharged at one year follow-up.We aim to highlight the need to have a low threshold to further evaluate symptomatic children after fracture healing of an undisplaced talar neck fracture for a possible associated loose bodyin the ankle joint.
基金Supported by The European Union Seventh Framework Programme through project ANTIGONE:Anticipating the global onset of novel epidemics,No.278976
文摘Rabies is a disease caused following infection of the brainby the rabies virus(RABV). The principle mechanism of transmission is through a bite wound. The virus infects peripheral nerves and moves to the central nervous system(CNS). There appears to be little involvement of other organ systems and little detectable immune stimulation prior to infection of the CNS. This failure of the mammalian immune system to respond to rabies virus infection leads, in the overwhelming majority of cases, to death of the host. To some extent, this failure is likely due to the exclusive replication of RABV in neurons and the limited ability to generate, sufficiently rapidly, an anti-viral antibody response in situ. This is reflected in the ability of post-exposure vaccination, when given early after infection, to prevent disease. The lack of immune stimulation during RABV infection preceding neural invasion is the Achilles heel of the immune response. Whilst many viruses infect the brain, causing encephalitis and neuronal deficit, none are as consistently fatal to the host as RABV. This is in part due to prior replication of many viruses in peripheral, non-neural tissue by other viruses that allows timely activation of the immune response before the host is overwhelmed. Our current understanding of the correlates of protection for rabies suggests that it is the action of neutralising antibodies that prevent infection and control spread of RABV. Furthermore, it tells us that the induction of immunity can protect and understanding how and why this happens is critical to controlling infection. However, the paradigm of antibody development suggests that antigen presentation overwhelmingly occurs in lymphoid tissue(germinal and non-germinal centres) and these are external to the CNS. In addition, the blood-brain-barrier may provide a block to the delivery of immune effectors(antibodies/plasma B-cells) entering where they are needed. Alternatively, there may be insufficient antigen exposure after natural infection to mount an effective response or the virus actively suppresses immune function. To improve our ability to treat this fatal infection it is imperative to understand how immunity to RABV develops and functions so that parameters of protectionare better defined.
基金USDA is an equal opportunity provider and employer.D.B.L.acknowledges support from USDA-NIFA postdoctoral fellowship(2011-67012-30696)P.A.F.acknowledges support from USDA-NIFA(2010-65615-20632)Funding.the National Science Foundation Plant Genome Research Program(IOS-0922457)to T.E.J.,C.V.H.and P.A.F.Conflict of interest statement.None declared。
文摘Aims Variation in precipitation strongly influences plant growth,species distributions and genetic diversity.intraspecific variation in pheno-typic plasticity,the ability of a genotype to alter its growth,morphol-ogy or physiology in response to the environment,could influence species responses to changing precipitation and climate change.Despite this,the patterns and mechanisms of intraspecific varia-tion in plasticity to variable precipitation,and the degree to which genotype responses to precipitation are influenced by variation in edaphic conditions,remain poorly understood.Thus,we determined whether genotypes of a widespread C_(4) grass(Panicum virgatum L.,switchgrass)varied in aboveground productivity in response to changes in precipitation,and if site edaphic conditions modified genotype aboveground productivity responses to precipitation.We also determined if genotype productivity responses to precipitation are related to plasticity in underlying growth and phenological traits.Methods Nine P.virgatum genotypes originating from an aridity gradient were grown under four treatments spanning the 10th to the 90th percentiles of annual precipitation at two sites in central Texas:one site with deep,fine-textured soils and another site with shallow,coarse-textured soils.We measured volumetric soil water content(VWC),aboveground net primary productivity(ANPP),tiller pro-duction(tiller number),average tiller mass,canopy height,leaf area index(LAi)and flowering time on all plants at both sites and examined genotype responses to changes in precipitation.Important Findings Across precipitation treatments,VWC was 39%lower and more variable at the site with shallow,coarse-textured soils compared to the site with deep,fine-textured soils.ANPP averaged across genotypes and precipita-tion treatments was also 103%higher at the site with deep,fine-textured soils relative to the site with shallow,coarse-textured soils,indicating substantial differences in site water limitation.Where site water limi-tation was higher,ANPP of most genotypes increased with increasing precipitation.Where site water limitation was less,genotypes expressed variable plasticity in response to precipitation,from no change to almost a 5-fold increase in ANPP with increasing precipitation.Genotype ANPP increased with greater tiller mass,LAi and later flowering time at both sites,but not with tiller number at either site.Genotype ANPP plasticity increased with genotype tiller mass and LAi plasticity at the site with deep,fine-textured soils,and only with genotype tiller mass plasticity at the site with shallow,coarse-textured soils.Thus,variation in genotype ANPP plasticity was explained primarily by variation in tiller and leaf growth.Genotype ANPP plasticity was not associated with temperature or aridity at the genotype’s origin.Edaphic factors such as soil depth and texture may alter genotype ANPP responses to precipitation,and the underlying growth traits contributing to the ANPP response.Thus,edaphic factors may contribute to spatial variation in genotype performance and success under altered precipitation.
