In the 'dance language' of honeybees, the dancer generates a specific, coded message that describes the direction and distance from the hive of a new food source, and this message is displaced in ...both space and time from the dancer's discovery of that source. Karl von Frisch concluded that bees 'recruited' by this dance used the information encoded in it to guide them directly to the remote food source, and this Nobel Prize-winning discovery revealed the most sophisticated example of non-primate communication that we know of. In spite of some initial scepticism, almost all biologists are now convinced that von Frisch was correct, but what has hitherto been lacking is a quantitative description of how effectively recruits translate the code in the dance into flight to their destinations. Using harmonic radar to record the actual flight paths of recruited bees, we now provide that description.
Methicillin‐resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant enterococcus (VRE) infections cause significant morbidity and mortality among liver transplant candidates and recipients. ...To assess rates of MRSA and VRE colonization, we obtained active surveillance cultures from 706 liver transplant candidates and recipients within 24 h of admission to an 11‐bed liver transplant ICU from October 2000 to December 2005. Patients were followed prospectively to determine the cumulative risk of MRSA or VRE infection or death by colonization status. Outcomes were assessed by Kaplan–Meier survival analysis and Cox regression and multivariate logistic regression adjusting for covariates. The prevalence of newly detected MRSA nasal and VRE rectal colonization was 6.7% and 14.6%, respectively. Liver transplant candidates and recipients with MRSA colonization had an increased risk of MRSA infection (adjusted OR = 15.64, 95% CI 6.63–36.89) but not of death (adjusted OR = 1.00, 95% CI 0.43–2.30), whereas those with VRE colonization had an increased risk both of VRE infection (adjusted OR = 3.61, 95% CI 2.01–6.47) and of death (adjusted OR = 2.12, 95% CI 1.27–3.54) compared with noncolonized patients. Prevention and control strategies, including use of active surveillance cultures, should be implemented to reduce the rates of both MRSA and VRE colonization in this high‐risk patient population.
Liver transplant candidates and recipients who are colonized with methicillin resistant Staphylococcus aureus or vancomycin resistant enterococcus are at significantly increased risk of infection with these multiple‐resistant organisms compared to patients who are not, while the impact of colonization on mortality is variable.
Delirium is common after surgery, although the aetiology is poorly defined. Brain-derived neurotrophic factor (BDNF) is a neurotrophin important in neurotransmission and neuroplasticity. Decreased ...levels of BDNF have been associated with poor cognitive outcomes, but few studies have characterized the role of BDNF perioperatively. We hypothesized that intraoperative decreases in BDNF levels are associated with postoperative delirium.
Patients undergoing spine surgery were enrolled in a prospective cohort study. Plasma BDNF was collected at baseline and at least hourly intraoperatively. Delirium was assessed using rigorous methods, including the Confusion Assessment Method (CAM) and CAM for the intensive care unit. Associations of changes in BDNF and delirium were examined using regression models.
Postoperative delirium developed in 32 of 77 (42%) patients. The median baseline BDNF level was 7.6 ng ml−1 interquartile range (IQR) 3.0–11.2 and generally declined intraoperatively median decline 61% (IQR 31–80). There was no difference in baseline BDNF levels by delirium status. However, the percent decline in BDNF was greater in patients who developed delirium median 74% (IQR 51–82) vs in those who did not develop delirium median 50% (IQR 14–79); P=0.03. Each 1% decline in BDNF was associated with increased odds of delirium in unadjusted {odds ratio OR 1.02 95% confidence interval (CI) 1.00–1.04; P=0.01}, multivariable-adjusted OR 1.02 (95% CI 1.00–1.03); P=0.03, and propensity score–adjusted models OR 1.02 (95% CI 1.00–1.04); P=0.03.
We observed an association between intraoperative decline in plasma BDNF and delirium. These preliminary results need to be confirmed but suggest that plasma BDNF levels may be a biomarker for postoperative delirium.
A complete sample of 96 faint (S > 0.5 mJy) radio galaxies is selected from the Tenth Cambridge (10C) survey at 15.7 GHz. Optical spectra are used to classify 17 of the sources as high-excitation or ...low-excitation radio galaxies (HERGs and LERGs, respectively), for the remaining sources three other methods are used; these are optical compactness, X-ray observations and mid-infrared colour–colour diagrams. 32 sources are HERGs and 35 are LERGs while the remaining 29 sources could not be classified. We find that the 10C HERGs tend to have higher 15.7-GHz flux densities, flatter spectra, smaller linear sizes and be found at higher redshifts than the LERGs. This suggests that the 10C HERGs are more core dominated than the LERGs. Lower-frequency radio images, linear sizes and spectral indices are used to classify the sources according to their radio morphology; 18 are Fanaroff and Riley type I or II sources, a further 13 show some extended emission, and the remaining 65 sources are compact and are referred to as FR0 sources. The FR0 sources are sub-divided into compact, steep-spectrum sources (13 sources) or gigahertz-peaked spectrum sources (10 sources) with the remaining 42 in an unclassified class. FR0 sources are more dominant in the subset of sources with 15.7-GHz flux densities <1 mJy, consistent with the previous result that the fainter 10C sources have flatter radio spectra. The properties of the 10C sources are compared to the higher-flux density Australia Telescope 20 GHz (AT20G) survey. The 10C sources are found at similar redshifts to the AT20G sources but have lower luminosities. The nature of the high-frequency selected objects changes as flux density decreases; at high flux densities the objects are primarily quasars, while at low flux densities radio galaxies dominate.
Approximately 1700 Pg of soil carbon (C) are stored in the northern circumpolar permafrost zone, more than twice as much C than in the atmosphere. The overall amount, rate, and form of C released to ...the atmosphere in a warmer world will influence the strength of the permafrost C feedback to climate change. We used a survey to quantify variability in the perception of the vulnerability of permafrost C to climate change. Experts were asked to provide quantitative estimates of permafrost change in response to four scenarios of warming. For the highest warming scenario (RCP 8.5), experts hypothesized that C release from permafrost zone soils could be 19–45 Pg C by 2040, 162–288 Pg C by 2100, and 381–616 Pg C by 2300 in CO
2
equivalent using 100-year CH
4
global warming potential (GWP). These values become 50 % larger using 20-year CH
4
GWP, with a third to a half of expected climate forcing coming from CH
4
even though CH
4
was only 2.3 % of the expected C release. Experts projected that two-thirds of this release could be avoided under the lowest warming scenario (RCP 2.6). These results highlight the potential risk from permafrost thaw and serve to frame a hypothesis about the magnitude of this feedback to climate change. However, the level of emissions proposed here are unlikely to overshadow the impact of fossil fuel burning, which will continue to be the main source of C emissions and climate forcing.
In patients with a particular disease or health condition, stratified medicine seeks to identify those who will have the most clinical benefit or least harm from a specific treatment. In this ...article, the fourth in the PROGRESS series, the authors discuss why prognosis research should form a cornerstone of stratified medicine, especially in regard to the identification of factors that predict individual treatment response
Little is known about Clostridioides difficile infection (CDI) in patients with cystic fibrosis (CF). The aim of this study was to investigate the prevalence, molecular epidemiology and risk factors ...for CDI in asymptomatic and symptomatic adults with CF in Western Australia.
Faecal samples from symptomatic and asymptomatic patients were prospectively collected and tested for the presence of C. difficile by toxigenic culture. Ribotyping was performed by established protocols. Logistic regression analysis was performed to analyse the risk factors for C. difficile colonization and infection. Extensive environmental sampling was performed within the CF clinic in Perth.
The prevalence rates of asymptomatic toxigenic and non-toxigenic C. difficile colonization were 30% (14/46 patients) and 24% (11/46 patients), respectively. Fifteen ribotypes (RTs) of C. difficile were identified, of which non-toxigenic RT 039 was the most common. Among the symptomatic patients, the prevalence of toxigenic CDI was 33% (11/33 patients). Impaired glucose tolerance/diabetes mellitus and duration of intravenous antibiotic use in the past 12 months were significantly associated with increased risk of asymptomatic toxigenic C. difficile carriage and CDI. A trend towards higher CF transmembrane conductance regulator modulator treatment was observed in the CDI group. Extensive environmental sampling showed no evidence of toxigenic C. difficile contamination within the CF clinic.
A high prevalence of asymptomatic carriage of toxigenic C. difficile was observed in adults with CF, comparable with that observed in the symptomatic CF population. There was no evidence of direct person-to-person transmission.
Death receptor activation triggers recruitment of FADD, which via its death effector domain (DED) engages the DEDs of procaspase 8 and its inhibitor FLIP to form death-inducing signalling complexes ...(DISCs). The DEDs of FADD, FLIP and procaspase 8 interact with one another using two binding surfaces defined by α1/α4 and α2/α5 helices, respectively. Here we report that FLIP has preferential affinity for the α1/α4 surface of FADD, whereas procaspase 8 has preferential affinity for FADD's α2/α5 surface. These relative affinities contribute to FLIP being recruited to the DISC at comparable levels to procaspase 8 despite lower cellular expression. Additional studies, including assessment of DISC stoichiometry and functional assays, suggest that following death receptor recruitment, the FADD DED preferentially engages FLIP using its α1/α4 surface and procaspase 8 using its α2/α5 surface; these tripartite intermediates then interact via the α1/α4 surface of FLIP DED1 and the α2/α5 surface of procaspase 8 DED2.
PDF
