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911.
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913.
Alan Soo David G. Healy Hatim El-Bashier Sandra Shaw Alfred E. Wood 《Cell and tissue banking》2011,12(3):185-190
Human donor heart valves remain essential for many reconstructive heart procedures. Heart valve donations are a scarce resource
which must be used efficiently and safely. Infection transmission remains a potential risk with homograft valve use. Early
experience with homograft valves identified high rates of microbial contamination at collection and initiated the practise
of immersion in an antibiotic cocktail. Many centres rely on the microbiology screening after exposure to the antibiotic cocktail.
We in our centre accept or reject valves on the basis of the microbiology screening at the time of collection prior to immersion
in antibiotic solution. We wanted to compare our rate of valve discard and the rate of microbial contamination at implant
with other centres. Valves are collected for the Irish Heart Valve Tissue Bank through partnership between the National Centre
for Cardiothoracic Surgery and the Irish Blood Transfusion Service. Valves are collected in a surgical theatre setting and
processed in dedicated section of the Irish Blood Transfusion Board. Tissues are screening for microbiology at collection
and also at implantation. A total of 564 human heart valves and valve conduits were processed through the service during the
study period. 167 (29.6%) were discarded during the processing and storage stages. The major reason for this in 117 cases
was unsatisfactory microbiology on initial tissue screening. Repeat screening of accepted valves at the time of implantation
identified positive cultures in only 0.9%. Optimal use of these limited resources is clearly important. However recipient
safety remains paramount. One-fifth of collected valves are discarded at the processing stage due to positive microbiology
screening. This is a higher rate of discard then other centres which reject 5.6–10% due to positive microbiology. However
our rate of contamination at time of implant is lower then the 3% rate reported elsewhere. We are satisfied that our current
discard rate, although significant, reflects rigorous quality control and the optimal balance between valve availability and
patient safety. 相似文献
914.
Graham NA Chabanet P Evans RD Jennings S Letourneur Y Aaron Macneil M McClanahan TR Ohman MC Polunin NV Wilson SK 《Ecology letters》2011,14(4):341-348
With rapidly increasing rates of contemporary extinction, predicting extinction vulnerability and identifying how multiple stressors drive non-random species loss have become key challenges in ecology. These assessments are crucial for avoiding the loss of key functional groups that sustain ecosystem processes and services. We developed a novel predictive framework of species extinction vulnerability and applied it to coral reef fishes. Although relatively few coral reef fishes are at risk of global extinction from climate disturbances, a negative convex relationship between fish species locally vulnerable to climate change vs. fisheries exploitation indicates that the entire community is vulnerable on the many reefs where both stressors co-occur. Fishes involved in maintaining key ecosystem functions are more at risk from fishing than climate disturbances. This finding is encouraging as local and regional commitment to fisheries management action can maintain reef ecosystem functions pending progress towards the more complex global problem of stabilizing the climate. 相似文献
915.
Marja Simpson Geoff M. Gurr Aaron T. Simmons Steve D. Wratten David G. James Gary Leeson Helen I. Nicol 《Agricultural and Forest Entomology》2011,13(1):45-57
- 1 Plants produce natural enemy‐attracting semiochemicals known as herbivore‐induced plant volatiles (HIPV) in response to herbivore damage. Deployment of synthetic HIPV in crops could enhance the biological control of pests. To test this, six HIPV [methyl salicylate (MeSA), methyl anthranilate (MeA), methyl jasmonate (MeJA), benzaldehyde (Be), cis‐3‐hexenyl acetate (HA), cis‐hexen‐1‐ol (He)] in three concentrations (0.5%, 1.0% and 2.0% v/v) mixed with a vegetable oil adjuvant, Synertrol® (Organic Crop Protectants Pty Ltd, Australia), were sprayed onto winegrape, broccoli and sweet corn plants.
- 2 The relative abundance of insects within treated plots was assessed with non‐attracting, transparent sticky traps at varying time intervals up to 22 days after spraying.
- 3 In the vineyard experiment, Trichogrammatidae responded to Be and MeA (0.5%) and Be (1.0%); Encyrtidae and Bethylidae responded to MeA (1.0%); Scelionidae responded to all compounds at 1.0% and 2.0%; and predatory insects responded to MeA. In sweet corn, parasitoids as a group and Encyrtidae responded to MeA (0.5%); Braconidae responded to all compounds at 0.5% and Synertrol‐only; thrips responded to all compounds at 0.5% and 1.0%; while all parasitoids responded to all compounds at 0.5% and 1.0% and Synertrol‐only. In broccoli, parasitoids as a group and Scelionidae responded to Be, HA, He and Synertrol‐only; Trichogrammatidae responded to Be (0.5%), He (0.5% and 1.0%), MeJA (1.0%) and MeSA (0.5%); and thrips responded to all compounds at to 0.5% and 1.0%.
- 4 Significant attraction of insects occurred up to 6 days after the HIPV application, suggesting that plants may have been induced to produce endogenous volatiles that attracted insects over an extended period.
- 5 The results obtained are discussed in relation to the potential utility of synthetic HIPV to enhance the biological control of pests.
916.
Rapid and efficient clathrin-mediated endocytosis revealed in genome-edited mammalian cells 总被引:1,自引:0,他引:1
Doyon JB Zeitler B Cheng J Cheng AT Cherone JM Santiago Y Lee AH Vo TD Doyon Y Miller JC Paschon DE Zhang L Rebar EJ Gregory PD Urnov FD Drubin DG 《Nature cell biology》2011,13(3):331-337
Clathrin-mediated endocytosis (CME) is the best-studied pathway by which cells selectively internalize molecules from the plasma membrane and surrounding environment. Previous live-cell imaging studies using ectopically overexpressed fluorescent fusions of endocytic proteins indicated that mammalian CME is a highly dynamic but inefficient and heterogeneous process. In contrast, studies of endocytosis in budding yeast using fluorescent protein fusions expressed at physiological levels from native genomic loci have revealed a process that is very regular and efficient. To analyse endocytic dynamics in mammalian cells in which endogenous protein stoichiometry is preserved, we targeted zinc finger nucleases (ZFNs) to the clathrin light chain A and dynamin-2 genomic loci and generated cell lines expressing fluorescent protein fusions from each locus. The genome-edited cells exhibited enhanced endocytic function, dynamics and efficiency when compared with previously studied cells, indicating that CME is highly sensitive to the levels of its protein components. Our study establishes that ZFN-mediated genome editing is a robust tool for expressing protein fusions at endogenous levels to faithfully report subcellular localization and dynamics. 相似文献
917.
Akhtar A Fuchs E Mitchison T Shaw RJ St Johnston D Strasser A Taylor S Walczak C Zerial M 《Nature reviews. Molecular cell biology》2011,12(10):669-674
Nature Reviews Molecular Cell Biology celebrated its 10-year anniversary during this past year with a series of specially commissioned articles. To complement this, here we have asked researchers from across the field for their insights into how molecular cell biology research has evolved during this past decade, the key concepts that have emerged and the most promising interfaces that have developed. Their comments highlight the broad impact that particular advances have had, some of the basic understanding that we still require, and the collaborative approaches that will be essential for driving the field forward. 相似文献
918.
In the 40 years since Aaron Beck first proposed his cognitive model of depression, the elements of this model--biased attention, biased processing, biased thoughts and rumination, biased memory, and dysfunctional attitudes and schemas--have been consistently linked with the onset and maintenance of depression. Although numerous studies have examined the neural mechanisms that underlie the cognitive aspects of depression, their findings have not been integrated with Beck's cognitive model. In this Review, we identify the functional and structural neurobiological architecture of Beck's cognitive model of depression. Although the mechanisms underlying each element of the model differ, in general the negative cognitive biases in depression are facilitated by increased influence from subcortical emotion processing regions combined with attenuated top-down cognitive control. 相似文献
919.
ObjectivesTo evaluate the prevalence and predictors of vitamin D insufficiency (VDI) in children In Great Britain.DesignA nationally representative cross-sectional study survey of children (1102) aged 4–18 years (999 white, 570 male) living in private households (January 1997–1998). Interventions provided information about dietary habits, physical activity, socio-demographics, and blood sample. Outcome measures were vitamin D insufficiency (<50 nmol/L).ResultsVitamin D levels (mean = 62.1 nmol/L, 95%CI 60.4–63.7) were insufficient in 35%, and decreased with age in both sexes (p<0.001). Young People living between 53–59 degrees latitude had lower levels (compared with 50–53 degrees, p = 0.045). Dietary intake and gender had no effect on vitamin D status. A logistic regression model showed increased risk of VDI in the following: adolescents (14–18 years old), odds ratio (OR) = 3.6 (95%CI 1.8–7.2) compared with younger children (4–8 years); non white children (OR = 37 [95%CI 15–90]); blood levels taken December-May (OR = 6.5 [95%CI 4.3–10.1]); on income support (OR = 2.2 [95%CI 1.3–3.9]); not taking vitamin D supplementation (OR = 3.7 [95%CI 1.4–9.8]); being overweight (OR 1.6 [95%CI 1.0–2.5]); <1/2 hour outdoor exercise/day/week (OR = 1.5 [95%CI 1.0–2.3]); watched >2.5 hours of TV/day/week (OR = 1.6[95%CI 1.0–2.4]).ConclusionWe confirm a previously under-recognised risk of VDI in adolescents. The marked higher risk for VDI in non-white children suggests they should be targeted in any preventative strategies. The association of higher risk of VDI among children who exercised less outdoors, watched more TV and were overweight highlights potentially modifiable risk factors. Clearer guidelines and an increased awareness especially in adolescents are needed, as there are no recommendations for vitamin D supplementation in older children. 相似文献
920.