Cerebral angiography is an invasive procedure associated with a small, but definite risk of neurological morbidity. In this study we sought to establish the nature and rate of complications at our ...institution among a large prospective cohort of consecutive patients. Also, the data were analysed in an attempt to identify risk factors for complications associated with catheter angiography.
Data were prospectively collected for a consecutive cohort of patients undergoing diagnostic cerebral angiography between January 2001 and May 2006. A total of 2,924 diagnostic cerebral angiography procedures were performed during this period. The following data were recorded for each procedure: date of procedure, patient age and sex, clinical indication, referring specialty, referral status (routine/emergency), operator, angiographic findings, and the nature of any clinical complication or asymptomatic adverse event (arterial dissection).
Clinical complications occurred in 23 (0.79%) of the angiographic procedures: 12 (0.41%) significant puncture-site haematomas, 10 (0.34%) transient neurological events, and 1 nonfatal reaction to contrast agent. There were no permanent neurological complications. Asymptomatic technical complications occurred in 13 (0.44%) of the angiographic procedures: 3 groin dissections and 10 dissections of the cervical vessels. No patient with a neck dissection suffered an immediate or delayed stroke. Emergency procedures (P = 0.0004) and angiography procedures performed for intracerebral haemorrhage (P = 0.02) and subarachnoid haemorrhage (P = 0.04) were associated with an increased risk of complications.
Neurological complications following cerebral angiography are rare (0.34%), but must be minimized by careful case selection and the prudent use of alternative noninvasive angiographic techniques, particularly in the acute setting. The low complication rate in this series was largely due to the favourable case mix.
Knowledge of exact properties of the exchange-correlation (xc) functional is important for improving the approximations made within density functional theory. Features such as steps in the exact xc ...potential are known to be necessary for yielding accurate densities, yet little is understood regarding their shape, magnitude, and location. We use systems of a few electrons, where the exact electron density is known, to demonstrate general properties of steps. We find that steps occur at points in the electron density where there is a change in the 'local effective ionization energy' of the electrons. We provide practical arguments, based on the electron density, for determining the position, shape, and height of steps for ground-state systems, and extend the concepts to time-dependent systems. These arguments are intended to inform the development of approximate functionals, such as the mixed localization potential (MLP), which already demonstrate their capability to produce steps in the Kohn-Sham potential.
To determine predictors of inability to return to work due to health six-months after intensive care admission; and compare functional recovery between patients who had not returned to work and ...employed patients.
Participants were working adults admitted to ICU who received >24 h of mechanical ventilation. Outcomes included inability to return to work due to health at six-months post-ICU admission, disability, health status, anxiety, depression and post-traumatic stress.
Of 107 patients, 31 (29%) were unable to return to work due to health at six-months after ICU admission. Predictors of inability to return to work included longer hospital stay (odds ratio OR, 1.05; 95% confidence interval CI, 1.02–1.08; P = .004); lower Glasgow Coma Scale (GCS) at admission (OR, 0.86; CI, 0.75–0.99; P = .03); and admission due to major trauma (OR, 8.83; CI, 2.57–30.38; P < .001). Compared to employed patients, those who had not returned to work reported higher levels of disability and psychological distress, and poorer health-related quality of life.
Major trauma, lower GCS and increased hospital length of stay predicted inability to return to work due to health at six-months post-ICU admission. Compared to employed patients, those who had not returned to work reported poorer functional recovery.
•One third of patients mechanically ventilated for >24 h had not returned to work at six months due to their health.•Predictors of being unable to return to work due to poor health included increased hospital length of stay, major trauma and lower Glasgow Coma Scale.•Inability to return to work due to health was associated with anxiety, depression, post-traumatic stress and reduced health related quality of life.
Adults with cystic fibrosis (CF) have been reported to be at five to ten-fold risk (25 to 30 fold risk after solid organ transplant) of colorectal cancer (CRC) than the general population. Limited ...publications to date have reported on practical aspects of achieving adequate colonic cleanse producing good visualisation. In this study, we compared two bowel preparation regimens, standard bowel preparation and a modified CF bowel preparation.
A non-randomised study of adults with CF attending a single centre, requiring colonoscopy investigation were selected. Between 2001 and 2015, 485 adults with CF attended the clinic; 70 adults with CF had an initial colonoscopy procedure. After five exclusions, standard bowel preparation was prescribed for 27 patients, and modified CF bowel preparation for 38 patients. Demographic and clinical data were collected for all consenting patients.
There was a significant difference between modified CF bowel preparation group and standard bowel preparation group in bowel visualisation outcomes, with the modified CF bowel preparation group having a higher proportion of "excellent/good" GI visualisation cleanse (50.0% versus 25.9%) and lower rates of "poor" visualisation cleanse (10.5% versus 44.5%) than standard bowel preparation (p = 0.006). Rates of "fair" GI cleanse visualisation were similar between the two groups (39.4% versus 29.6%) (Additional file 1: Table S1). Detection rates of adenomatous polyps at initial colonoscopy was higher in modified CF bowel preparation cohort than with standard preparation group (50.0% versus 18.5%, p < 0.01). Positive adenomatous polyp detection rate in patient's age > 40 years of age was higher (62.5%) than those < 40 years of age (24.3%) (p = 0.003). Colonic adenocarcinoma diagnosis was similar in both groups.
This study primarily highlights that standard colonoscopy bowel preparation is often inadequate in patients with CF, and that colonic lavage using modified CF bowel preparation is required to obtain good colonic visualisation. A higher rate of polyps in patients over 40 years of age (versus less than 40 years) was evident. These results support adults with CF considered for colonoscopy screening at 40 years of age, or prior to this if symptomatic; which is earlier than CRC screening in the non-CF Australian population.
Biologists commonly compare variances among samples, to test whether underlying populations have equal spread. However, despite warnings from statisticians, incorrect testing is rife. Here we show ...that one of the most commonly employed of these tests, the F test, is extremely sensitive to deviations from normality. The F test suffers greatly elevated false positive errors when the underlying distributions are heavy tailed, a distribution feature that is very hard to detect using standard normality tests. We highlight and assess a selection of parametric, jackknife and permutation tests, consider their performance in terms of false positives, and power to detect signal when it exists, then show correct methods to compare measures of variation among samples. Based on these assessments, we recommend using Levene's test, Box–Anderson test, jackknifing or permutation tests to compare variances when normality is in doubt. Levene's and Box–Anderson tests are the most powerful at small sample sizes, but the Box–Anderson test may not control type I error for extremely heavy-tailed distributions. As noted previously, do not use F tests to compare variances.
•Behaviourists often wish to compare variances.•F tests are frequently used to make these comparisons, but should not be.•Levine's test is probably the best way to compare variance equality.
The European lobster Homarus gammarus is a marine crustacean prized for seafood, but populations across its range are threatened by fishery overexploitation. The species’ larval stages are ...planktonic, suggesting considerable dispersal among populations. The potential threats of overexploitation and erosion of population structure due to hatchery releases or inadvertent introductions make it important to understand the genetic structuring of populations across multiple geographic scales. Here we assess lobster population structure at a fine scale in Cornwall, southwestern UK, where a hatchery-stocking operation introduces cultured individuals into the wild stock, and at a broader European level, in order to compare the spatial scale of hatchery releases with that of population connectivity. Microsatellite genotypes of 24 individuals from each of 13 locations in Cornwall showed no fine-scale population structure across distances of up to ~230 km. Significant differentiation and isolation by distance were detected at a broader scale, using 300 additional individuals comprising a further 15 European samples. Signals of genetic heterogeneity were evident between an Atlantic cluster and samples from Sweden. Connectivity within the Atlantic and Swedish clusters was high, although evidence for isolation by distance and a transitional zone within the eastern North Sea suggested that direct gene exchange between these stocks is limited and fits a stepping-stone model. We conclude that hatchery-reared lobsters should not be released where broodstock are distantly sourced but, using Cornwall as a case study, microsatellites revealed no evidence that the normal release of hatchery stock exceeds the geographic scale of natural connectivity.
Selfish Genetic Elements Promote Polyandry in a Fly Price, T.A.R; Hodgson, D.J; Lewis, Z ...
Science (American Association for the Advancement of Science),
11/2008, Letnik:
322, Številka:
5905
Journal Article
Recenzirano
It is unknown why females mate with multiple males when mating is frequently costly and a single copulation often provides enough sperm to fertilize all a female's eggs. One possibility is that ...remating increases the fitness of offspring, because fertilization success is biased toward the sperm of high-fitness males. We show that female Drosophila pseudoobscura evolved increased remating rates when exposed to the risk of mating with males carrying a deleterious sex ratio-distorting gene that also reduces sperm competitive ability. Because selfish genetic elements that reduce sperm competitive ability are generally associated with low genetic fitness, they may represent a common driver of the evolution of polyandry.
•Coffee is one of the most widely consumed beverages in the Western world.•Coffee intake has been associated with reduced risk of many chronic diseases, including cardiovascular disease.•Green coffee ...bean extract did not protect against features of the metabolic syndrome in mice fed a high-fat diet.
We have investigated the effects of the major polyphenol in coffee, chlorogenic acid (CGA), on obesity, glucose intolerance, insulin resistance, systemic oxidative stress and endothelial dysfunction in a mouse model of the metabolic syndrome. Thirty C57BL6 mice were randomly divided into (n=10/group) (i) normal diet (ND), (ii) high fat diet (HFD), or (iii) high fat diet supplemented with 0.5% w/w green coffee bean extract (GCE) rich in chlorogenic acid (HFD+GCE). The high fat diet consisted of 28% fat and all animals were maintained on their diets for 12weeks. The mice fed a HFD and HFD+GCE displayed symptoms of the metabolic syndrome compared to their normal fed counterparts, although no endothelial dysfunction was detected in the abdominal aortas after 12weeks. GCE did not attenuate HFD-induced obesity, glucose intolerance, insulin resistance or systemic oxidative stress. Furthermore, GCE did not protect against ex vivo oxidant (hypochlorous acid)-induced endothelial dysfunction.
Treatment for medulloblastoma during childhood impairs neurocognitive function in survivors. While those diagnosed at younger ages are most vulnerable, little is known about the long-term ...neurocognitive, functional, and physical outcomes in survivors as they approach middle age. In this retrospective cohort study, we assessed 20 adults who were treated with surgery and radiotherapy for medulloblastoma during childhood (median age at assessment, 21.9 years range, 18-47 years; median time since diagnosis, 15.5 years range, 6.5-42.2 years). Nine patients also underwent chemotherapy. Cross-sectional analyses of current neurocognitive, functional, and physical status were conducted. Data from prior neuropsychological assessments were available for 18 subjects; longitudinal analyses were used to model individual change over time for those subjects. The group was well below average across multiple neurocognitive domains, and 90% had required accommodations at school for learning disorders. Longer time since diagnosis, but not age at diagnosis, was associated with continued decline in working memory, a common sign of aging. Younger age at diagnosis was associated with lower intelligence quotient and academic achievement scores, even many years after treatment had been completed. The most common health complications in survivors were hearing impairment, second cancers, diabetes, hypertension, and endocrine deficiencies. Adult survivors of childhood medulloblastoma exhibit signs of early aging regardless of how young they were at diagnosis. As survival rates for brain tumors continue to improve, these neurocognitive and physical sequelae may become evident in survivors diagnosed at different ages across the lifespan. It will become increasingly important to identify factors that contribute to risk and resilience in this growing population.
The NASA Magnetospheric Multiscale mission has made in situ diffusion region and kinetic‐scale resolution measurements of asymmetric magnetic reconnection for the first time, in the Earth's ...magnetopause. The principal theoretical tool currently used to model collisionless asymmetric reconnection is particle‐in‐cell simulations. Many particle‐in‐cell simulations of asymmetric collisionless reconnection start from an asymmetric Harris‐type magnetic field but with distribution functions that are not exact equilibrium solutions of the Vlasov equation. We present new and exact equilibrium solutions of the Vlasov‐Maxwell system that are self‐consistent with one‐dimensional asymmetric current sheets, with an asymmetric Harris‐type magnetic field profile, plus a constant nonzero guide field. The distribution functions can be represented as a combination of four shifted Maxwellian distribution functions. This equilibrium describes a magnetic field configuration with more freedom than the previously known exact solution and has different bulk flow properties.
Plain Language Summary
Magnetic reconnection is a fundamental phenomenon in space science and is currently a subject of intense study. During a reconnection event, stored energy that had been bound up in stressed electromagnetic fields is released in the form of heat and the kinetic energy of particles. The NASA MMS mission is currently making measurements of these phenomena in the Earth's Magnetosphere, with unprecedented levels of accuracy and resolution. Our work presents a theoretical model of a structure in space known as an asymmetric current sheet such as the MMS mission encounters during a reconnection event. The model can be implemented into computer simulations, with which to compare to the results from MMS satellite data. This will help us understand the fundamental physics of asymmetric magnetic reconnection.
Key Points
New exact Vlasov‐Maxwell equilibria for 1D asymmetric current sheets
Written as a combination of four shifted Maxwellian distribution functions
Self‐consistent with asymmetric magnetic field, temperature, density, and pressure profiles
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