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111.
Biochemistry and expression of bacterial capsules. 总被引:2,自引:0,他引:2
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114.
Astrid Thomas Birgitte Hanel Jacob L. Marott Frederik Buchvald Jann Mortensen Kim G. Nielsen 《PloS one》2014,9(12)
Rationale
The diffusing capacity (DL) of the lung can be divided into two components: the diffusing capacity of the alveolar membrane (Dm) and the pulmonary capillary volume (Vc). DL is traditionally measured using a single-breath method, involving inhalation of carbon monoxide, and a breath hold of 8–10 seconds (DL,CO). This method does not easily allow calculation of Dm and Vc. An alternative single-breath method (DL,CO,NO), involving simultaneous inhalation of carbon monoxide and nitric oxide, and traditionally a shorter breath hold, allows calculation of Dm and Vc and the DL,NO/DL,CO ratio in a single respiratory maneuver. The clinical utility of Dm, Vc, and DL,NO/DL,CO in the pediatric age range is currently unknown but also restricted by lack of reference values.Objectives
The aim of this study was to establish reference ranges for the outcomes of DL,CO,NO with a 5 second breath hold, including the calculated outcomes Dm, Vc, and the DL,NO/DL,CO ratio, as well as to establish reference values for the outcomes of the traditional DL,CO method, with a 10 second breath hold in children.Methods
DL,CO,NO and DL,CO were measured in healthy children, of European descent, aged 5–17 years using a Jaeger Masterscreen PFT. The data were analyzed using the Generalized Additive Models for Location Scale and Shape (GAMLSS) statistical method.Measurements and Main Results
A total of 326 children were eligible for diffusing capacity measurements, resulting in 312 measurements of DL,CO,NO and 297 of DL,CO, respectively. Reference equations were established for the outcomes of DL,CO,NO and DL,CO, including the calculated values: Vc, Dm, and the DL,NO/DL,CO ratio.Conclusion
These reference values are based on the largest sample of children to date and may provide a basis for future studies of their clinical utility in differentiating between alterations in the pulmonary circulation and changes in the alveolar membrane in pediatric patients. 相似文献115.
Silvana Romio Daniel Weibel Jeanne P. Dieleman Henning K. Olberg Corinne S. de Vries Cormac Sammon Nick Andrews Henrik Svanstr?m Ditte M?lgaard-Nielsen Anders Hviid Maryse Lapeyre-Mestre Agnès Sommet Christel Saussier Anne Castot Harald Heijbel Lisen Arnheim-Dahlstr?m Par Sparen Mees Mosseveld Martijn Schuemie Nicoline van der Maas Bart C. Jacobs Tuija Leino Terhi Kilpi Jann Storsaeter Kari Johansen Piotr Kramarz Jan Bonhoeffer Miriam C. J. M. Sturkenboom 《PloS one》2014,9(1)
Background
The risk of Guillain-Barré syndrome (GBS) following the United States'' 1976 swine flu vaccination campaign in the USA led to enhanced active surveillance during the pandemic influenza (A(H1N1)pdm09) immunization campaign. This study aimed to estimate the risk of GBS following influenza A(H1N1)pdm09 vaccination.Methods
A self-controlled case series (SCCS) analysis was performed in Denmark, Finland, France, Netherlands, Norway, Sweden, and the United Kingdom. Information was collected according to a common protocol and standardised procedures. Cases classified at levels 1–4a of the Brighton Collaboration case definition were included. The risk window was 42 days starting the day after vaccination. Conditional Poisson regression and pooled random effects models estimated adjusted relative incidences (RI). Pseudo likelihood and vaccinated-only methods addressed the potential contraindication for vaccination following GBS.Results
Three hundred and three (303) GBS and Miller Fisher syndrome cases were included. Ninety-nine (99) were exposed to A(H1N1)pdm09 vaccination, which was most frequently adjuvanted (Pandemrix and Focetria). The unadjusted pooled RI for A(H1N1)pdm09 vaccination and GBS was 3.5 (95% Confidence Interval (CI): 2.2–5.5), based on all countries. This lowered to 2.0 (95% CI: 1.2–3.1) after adjustment for calendartime and to 1.9 (95% CI: 1.1–3.2) when we accounted for contra-indications. In a subset (Netherlands, Norway, and United Kingdom) we further adjusted for other confounders and there the RI decreased from 1.7 (adjusted for calendar month) to 1.4 (95% CI: 0.7–2.8), which is the main finding.Conclusion
This study illustrates the potential of conducting European collaborative vaccine safety studies. The main, fully adjusted analysis, showed that the RI of GBS was not significantly elevated after influenza A(H1N1)pdm09 vaccination (RI = 1.4 (95% CI: 0.7–2.8). Based on the upper limits of the pooled estimate we can rule out with 95% certainty that the number of excess GBS cases after influenza A(H1N1)pdm09 vaccination would be more than 3 per million vaccinated. 相似文献116.
Background
Rapid pre-clinical evaluation of chemotherapeutic agents against brain cancers and other neurological disorders remains largely unattained due to the presence of the blood-brain barrier (BBB), which limits transport of most therapeutic compounds to the brain. A synthetic peptide carrier, K16ApoE, was previously developed that enabled transport of target proteins to the brain by mimicking a ligand-receptor system. The peptide carrier was found to generate transient BBB permeability, which was utilized for non-covalent delivery of cisplatin, methotrexate and other compounds to the brain.Approach
Brain delivery of the chemotherapeutics and other agents was achieved either by injecting the carrier peptide and the drugs separately or as a mixture, to the femoral vein. A modification of the method comprised injection of K16ApoE pre-mixed with cetuximab, followed by injection of a ‘small-molecule’ drug.Principal findings
Seven-of-seven different small molecules were successfully delivered to the brain via K16ApoE. Depending on the method, brain uptake with K16ApoE was 0.72–1.1% for cisplatin and 0.58–0.92% for methotrexate (34-50-fold and 54–92 fold greater for cisplatin and methotrexate, respectively, with K16ApoE than without). Visually intense brain-uptake of Evans Blue, Light Green SF and Crocein scarlet was also achieved. Direct intracranial injection of EB show locally restricted distribution of the dye in the brain, whereas K16ApoE-mediated intravenous injection of EB resulted in the distribution of the dye throughout the brain. Experiments with insulin suggest that ligand-receptor signaling intrinsic to the BBB provides a natural means for passive transport of some molecules across the BBB.Significance
The results suggest that the carrier peptide can non-covalently transport various chemotherapeutic agents to the brain. Thus, the method offers an avenue for pre-clinical evaluation of various small and large therapeutic molecules against brain tumors and other neurological disorders. 相似文献117.
118.
Australia's tropical grasslands are dominated by C4grasses,characterized by their unique biochemistry and anatomy. Twonaturalized C4grasses (Panicum coloratum and Cenchrus ciliaris)were used to investigate whether high CO2partial pressure [p(CO2)] influences photosynthetic nitrogen use efficiency andplant nitrogen use efficiency (PNUE and NUE respectively). Plantswere grown for 30 d with four levels of N at p(CO2) of 38 or86 Pa. PNUE was calculated from leaf CO2assimilation rates (A)and leaf N concentrations, and NUE from total leaf N contentand plant dry mass. At each p(CO2), PNUE and NUE were greaterfor C. ciliaris than for P. coloratum due to higher A and drymass combined with lower leaf N concentrations. Elevatedp (CO2)increased PNUE of C. ciliaris only. This effect was due to lowerleaf N concentrations (area basis). At high p(CO2), NUE of C.ciliaris was also greater. This resulted from a 1.6-fold stimulationof dry mass by high p(CO2). Although dry mass of P. coloratumwas increased 1.2-fold by elevated p(CO2), its NUE was unaffected.Leaf transpiration rates were halved at elevated p(CO2), andwe suggest that this factor plays a major role in the growthresponse of C4grasses to high p(CO2). Copyright 2001 Annalsof Botany Company Panicum coloratum, Cenchrus ciliaris, nitrogen use efficiency, elevated CO2, leaf N concentration, growth, photosynthesis 相似文献
119.
Craig V.M. Barton Remko A. Duursma Belinda E. Medlyn David S. Ellsworth Derek Eamus David T. Tissue Mark A. Adams Jann Conroy Kristine Y. Crous Marion Liberloo Markus Löw Sune Linder Ross E. McMurtrie 《Global Change Biology》2012,18(2):585-595
Rising atmospheric concentrations of CO2 (Ca) can reduce stomatal conductance and transpiration rate in trees, but the magnitude of this effect varies considerably among experiments. The theory of optimal stomatal behaviour predicts that the ratio of photosynthesis to transpiration (instantaneous transpiration efficiency, ITE) should increase in proportion to Ca. We hypothesized that plants regulate stomatal conductance optimally in response to rising Ca. We tested this hypothesis with data from young Eucalyptus saligna Sm. trees grown in 12 climate‐controlled whole‐tree chambers for 2 years at ambient and elevated Ca. Elevated Ca was ambient + 240 ppm, 60% higher than ambient Ca. Leaf‐scale gas exchange was measured throughout the second year of the study and leaf‐scale ITE increased by 60% under elevated Ca, as predicted. Values of leaf‐scale ITE depended strongly on vapour pressure deficit (D) in both CO2 treatments. Whole‐canopy CO2 and H2O fluxes were also monitored continuously for each chamber throughout the second year. There were small differences in D between Ca treatments, which had important effects on values of canopy‐scale ITE. However, when Ca treatments were compared at the same D, canopy‐scale ITE was consistently increased by 60%, again as predicted. Importantly, leaf and canopy‐scale ITE were not significantly different, indicating that ITE was not scale‐dependent. Observed changes in transpiration rate could be explained on the basis that ITE increased in proportion to Ca. The effect of elevated Ca on photosynthesis increased with rising D. At high D, Ca had a large effect on photosynthesis and a small effect on transpiration rate. At low D, in contrast, there was a small effect of Ca on photosynthesis, but a much larger effect on transpiration rate. If shown to be a general response, the proportionality of ITE with Ca will allow us to predict the effects of Ca on transpiration rate. 相似文献
120.
Quantitative analyses of relevant molecules in faeces may have potential as future non-invasive measures of stress. This study examined levels of faecal corticosterone and immunoglubulin A (IgA) in young adult rats and how these levels varied according to age, gender and time of day. Faecal samples were collected from 40 young adult rats (7 weeks old, n = 20 and 10 weeks old, n = 20) of both sexes from two time windows: day and night. The concentrations of corticosterone and IgA were measured by ELISAs following organic solvent extraction and aqueous extraction, respectively, of the molecules from faecal pellets. The production of faeces per time unit was higher in males than in females, and linear correlations were found between the faecal concentrations of corticosterone and IgA and total amounts of the respective molecules excreted in faeces per kg body weight per hour. In all further analyses the levels of the two molecules were calculated as amounts secreted per kg of body weight per hour. There was no gender difference between females and males in the production of corticosterone and IgA, but 7-week-old animals excreted significantly higher amounts of both molecules than did 10-week-old rats. The levels of IgA excreted by female rats were higher in the evening than in the morning, and male rats excreted higher concentrations of corticosterone in the morning than in the evening. 相似文献