Bacterial polysaccharides have numerous clinical or industrial uses. Recombinant plants could offer the possibility of producing bacterial polysaccharides on a large scale and free of contaminating bacterial toxins and antigens. We investigated the feasibility of this proposal by cloning and expressing the gene for the type 3 synthase (cps3S) of Streptococcus pneumoniae in Nicotinia tabacum, using the pCambia2301 vector and Agrobacterium tumefaciens-mediated gene transfer. In planta the recombinant synthase polymerised plant-derived UDP-glucose and UDP-glucuronic acid to form type 3 polysaccharide. Expression of the cps3S gene was detected by RT-PCR and production of the pneumococcal polysaccharide was detected in tobacco leaf extracts by double immunodiffusion, Western blotting and high-voltage paper electrophoresis. Because it is used a component of anti-pneumococcal vaccines, the immunogenicity of the plant-derived type 3 polysaccharide was tested. Mice immunised with extracts from recombinant plants were protected from challenge with a lethal dose of pneumococci in a model of pneumonia and the immunised mice had significantly elevated levels of serum anti-pneumococcal polysaccharide antibodies. This study provides the proof of the principle that bacterial polysaccharide can be successfully synthesised in plants and that these recombinant polysaccharides could be used as vaccines to protect against life-threatening infections.
It is a truism that conceptual understanding of a hypothesis is required for its empirical investigation. However, the concept of recursion as articulated in the context of linguistic analysis has been perennially confused. Nowhere has this been more evident than in attempts to critique and extend Hauseretal's. (2002) articulation. These authors put forward the hypothesis that what is uniquely human and unique to the faculty of language—the faculty of language in the narrow sense (FLN)—is a recursive system that generates and maps syntactic objects to conceptual-intentional and sensory-motor systems. This thesis was based on the standard mathematical definition of recursion as understood by Gödel and Turing, and yet has commonly been interpreted in other ways, most notably and incorrectly as a thesis about the capacity for syntactic embedding. As we explain, the recursiveness of a function is defined independent of such output, whether infinite or finite, embedded or unembedded—existent or non-existent. And to the extent that embedding is a sufficient, though not necessary, diagnostic of recursion, it has not been established that the apparent restriction on embedding in some languages is of any theoretical import. Misunderstanding of these facts has generated research that is often irrelevant to the FLN thesis as well as to other theories of language competence that focus on its generative power of expression. This essay is an attempt to bring conceptual clarity to such discussions as well as to future empirical investigations by explaining three criterial properties of recursion: computability (i.e., rules in intension rather than lists in extension); definition by induction (i.e., rules strongly generative of structure); and mathematical induction (i.e., rules for the principled—and potentially unbounded—expansion of strongly generated structure). By these necessary and sufficient criteria, the grammars of all natural languages are recursive.
computability; FLN/FLB; Gödel; induction; recursion; syntax; Turing
Plant virus movement proteins compartmentalize replication complexes at plasmodesmata for localized RNA synthesis and directional trafficking of the virus between cells.
Plant viruses use movement proteins (MPs) to modify intercellular pores called plasmodesmata (PD) to cross the plant cell wall. Many viruses encode a conserved set of three MPs, known as the triple gene block (TGB), typified by Potato virus X (PVX). In this paper, using live-cell imaging of viral RNA (vRNA) and virus-encoded proteins, we show that the TGB proteins have distinct functions during movement. TGB2 and TGB3 established endoplasmic reticulum–derived membranous caps at PD orifices. These caps harbored the PVX replicase and nonencapsidated vRNA and represented PD-anchored viral replication sites. TGB1 mediated insertion of the viral coat protein into PD, probably by its interaction with the 5′ end of nascent virions, and was recruited to PD by the TGB2/3 complex. We propose a new model of plant virus movement, which we term coreplicational insertion, in which MPs function to compartmentalize replication complexes at PD for localized RNA synthesis and directional trafficking of the virus between cells.
This Review provides abstracts from a meeting held at the London School of Hygiene and Tropical Medicine, on April 11–12, 2013, to celebrate the legacy of John Snow. They describe conventional and unconventional applications of epidemiological methods to problems ranging from diarrhoeal disease, mental health, cancer, and accident care, to education, poverty, financial networks, crime, and violence. Common themes appear throughout, including recognition of the importance of Snow’s example, the philosophical and practical implications of assessment of causality, and an emphasis on the evaluation of preventive, ameliorative, and curative interventions, in a wide variety of medical and societal examples. Almost all self-described epidemiologists nowadays work within the health arena, and this is the focus of most of the societies, journals, and courses that carry the name epidemiology. The range of applications evident in these contributions might encourage some of these institutions to consider broadening their remits. In so doing, they may contribute more directly to, and learn from, non-health-related areas that use the language and methods of epidemiology to address many important problems now facing the world.
The early administration of tranexamic acid (TXA) to bleeding trauma patients reduces all-cause mortality without increasing the risk of vascular occlusive events. Indeed, the risk of arterial thrombosis appears to be reduced with TXA. In this commentary we hypothesize that TXA has an antithrombotic effect and explore potential mechanisms. These include inhibition of the inflammatory effects of plasmin, effects on platelets and effects on factors V and VIII. If proven, these antithrombotic effects would have major implications for the systemic use of TXA in surgical patients, where TXA has been clearly shown to reduce bleeding.
We aimed to determine to what extent covariate adjustment could affect power in a randomized controlled trial (RCT) of a heterogeneous population with traumatic brain injury (TBI).
Study Design and Setting
We analyzed 14-day mortality in 9497 participants in the Corticosteroid Randomisation After Significant Head Injury (CRASH) RCT of corticosteroid vs. placebo. Adjustment was made using logistic regression for baseline covariates of two validated risk models derived from external data (IMPACT) and from the CRASH data. The relative sample size (RESS) measure, defined as the ratio of the sample size required by an adjusted analysis to attain the same power as the unadjusted reference analysis, was used to assess the impact of adjustment.
Corticosteroid was associated with higher mortality compared to placebo (OR=1.25, 95% CI: 1.13, 1.39). RESS of 0.79 and 0.73 were obtained by adjustment using the IMPACT and CRASH models, respectively, which for example implies an increase from 80% to 88% and 91% power, respectively.
Moderate gains in power may be obtained using covariate adjustment from logistic regression in heterogeneous conditions such as TBI. Although analyses of RCTs might consider covariate adjustment to improve power, we caution against this approach in the planning of RCTs.
covariate adjustment; prognostic targeting; strict selection; relative sample size; power in clinical trials; traumatic brain injury
► Batch addition of paper waste in SSSF results in up to 11.6% (v/v) ethanol. ► Low overall enzyme loadings (3.7 FPU/g substrate). ► High cumulative substrate loadings (65% w/v). ► High ethanol concentrations will improve distillation efficiencies.
A fundamental goal of second generation ethanol production is to increase the ethanol concentration to 10% (v/v) or more to optimise distillation costs. Semi simultaneous saccharification and fermentations (SSSF) were conducted at small pilot scale (5 L) utilising fed-batch additions of solid shredded copier paper substrate. Early addition of Accellerase® 1500 at 16 FPU/g substrate and 30 U/g β-glucosidase followed by substrate only batch addition allowed low final equivalent enzyme concentrations to be achieved (3.7 FPU/g substrate) whilst maintaining digestion. Batch addition resulted in a cumulative substrate concentration equivalent to 65% (w/v). This in turn resulted in the production of high concentrations of ethanol (11.6% v/v). The success of this strategy relied on the capacity of the bioreactor to perform high shear mixing as required. Further research into the timing and number of substrate additions could lead to further improvement in overall yields from the 65.5% attained.
SSF, simultaneous saccharification and fermentation; SSSF, semi-simultaneous saccharification and fermentation; βG, beta-glucosidase (cellobiase); Simultaneous saccharification and fermentation (SSF); Cellulosic ethanol; Waste paper; Cellulase; Fermentation
Whilst mast cells participate in the immune defence against the intracellular bacterium Listeria monocytogenes, there is conflicting evidence regarding the ability of L. monocytogenes to infect mast cells. It is known that the pore-forming toxin listeriolysin (LLO) is important for mast cell activation, degranulation and the release of pro-inflammatory cytokines. Mast cells, however, are a potential source of a wide range of cytokines, chemokines and other mediators including osteopontin, which contributes to the clearing of L. monocytogenes infections in vivo, although its source is unknown. We therefore aimed to resolve the controversy of mast cell infection by L. monocytogenes and investigated the extent of mediator release in response to the bacterium. In this paper we show that the infection of bone marrow-derived mast cells by L. monocytogenes is inefficient and LLO-independent. LLO, however, is required for calcium-independent mast cell degranulation as well as for the transient and selective downregulation of cell surface CD117 (c-kit) on mast cells. We demonstrate that in addition to the key pro-inflammatory cytokines TNF-α and IL-6, mast cells release a wide range of other mediators in response to L. monocytogenes. Osteopontin, IL-2, IL-4, IL-13 and granulocyte macrophage colony-stimulating factor (GM-CSF), and chemokines including CCL2, CCL3, CCL4 and CCL5 are released in a MyD88-dependent manner. The wide range of mediators released by mast cells in response to L. monocytogenes may play an important role in the recruitment and activation of a variety of immune cells in vivo. The cocktail of mediators, however, is unlikely to skew the immune response to a particular effector response. We propose that mast cells provide a hitherto unreported source of osteopontin, and may provide an important role in co-ordinating the immune response during Listeria infection.
Vascular occlusive events can complicate recovery following trauma. We examined risk factors for venous and arterial vascular occlusive events in trauma patients and the extent to which the risk of vascular occlusive events varies with the severity of bleeding.
Methods and Findings
We conducted a cohort analysis using data from a large international, double-blind, randomised, placebo-controlled trial (The CRASH-2 trial) . We studied the association between patient demographic and physiological parameters at hospital admission and the risk of vascular occlusive events. To assess the extent to which risk of vascular occlusive events varies with severity of bleeding, we constructed a prognostic model for the risk of death due to bleeding and assessed the relationship between risk of death due to bleeding and risk of vascular occlusive events. There were 20,127 trauma patients with outcome data including 204 (1.01%) patients with a venous event (pulmonary embolism or deep vein thrombosis) and 200 (0.99%) with an arterial event (myocardial infarction or stroke). There were 81 deaths due to vascular occlusive events. Increasing age, decreasing systolic blood pressure, increased respiratory rates, longer central capillary refill times, higher heart rates and lower Glasgow Coma Scores (all p<0.02) were strong risk factors for venous and arterial vascular occlusive events. Patients with more severe bleeding as assessed by predicted risk of haemorrhage death had a greatly increased risk for all types of vascular occlusive event (all p<0.001).
Patients with severe traumatic bleeding are at greatly increased risk of venous and arterial vascular occlusive events. Older age and blunt trauma are also risk factors for vascular occlusive events. Effective treatment of bleeding may reduce venous and arterial vascular occlusive complications in trauma patients.
Infection with human papillomavirus type 16 (HPV-16) can lead to low- or high-grade squamous intraepithelial lesions (LSIL or HSIL). Here we show that these in vivo disease states can be replicated in raft cultures of early-pass HPV-16 episomal cell lines, at both the level of pathology and the level of viral gene expression. A reduced responsiveness to cell-cell contact inhibition and an increase in E6/E7 activity correlated closely with phenotype. Similar deregulation is likely to underlie the appearance of LSIL or HSIL soon after infection.
Traumatic brain injury (TBI) affects approximately 10 million people annually, of which intracranial hemorrhage is a devastating sequelae, occurring in one-third to half of cases. Patients in low and middle-income countries (LMIC) are twice as likely to die following TBI as compared to those in high-income countries. Diagnostic capabilities and treatment options for intracranial hemorrhage are limited in LMIC as there are fewer computed tomography (CT) scanners and neurosurgeons per patient as in high-income countries.
The Medical Research Council CRASH-1 trial was utilized to build this model. The study cohort included all patients from LMIC who received a CT scan of the brain (n = 5669). Prognostic variables investigated included age, sex, time from injury to randomization, pupil reactivity, cause of injury, seizure and the presence of major extracranial injury.
There were five predictors that were included in the final model; age, Glasgow Coma Scale, pupil reactivity, the presence of a major extracranial injury and time from injury to presentation. The model demonstrated good discrimination and excellent calibration (c-statistic 0.71). A simplified risk score was created for clinical settings to estimate the percentage risk of intracranial hemorrhage among TBI patients.
Simple prognostic models can be used in LMIC to estimate the risk of intracranial hemorrhage among TBI patients. Combined with clinical judgment this may facilitate risk stratification, rapid transfer to higher levels of care and treatment in resource-poor settings.
Neurosurgery; Trauma; Developing countries; Intracranial hemorrhage; Traumatic brain injury
Reliable identification of copy number aberrations (CNA) from comparative genomic hybridization data would be improved by the availability of a generalised method for processing large datasets. To this end, we developed swatCGH, a data analysis framework and region detection heuristic for computational grids. swatCGH analyses sequentially displaced (sliding) windows of neighbouring probes and applies adaptive thresholds of varying stringency to identify the 10% of each chromosome that contains the most frequently occurring CNAs. We used the method to analyse a published dataset, comparing data preprocessed using four different DNA segmentation algorithms, and two methods for prioritising the detected CNAs. The consolidated list of the most commonly detected aberrations confirmed the value of swatCGH as a simplified high-throughput method for identifying biologically significant CNA regions of interest.
The txt2stop trial has shown that mobile-phone-based smoking cessation support doubles biochemically validated quitting at 6 months. This study examines the cost-effectiveness of smoking cessation support delivered by mobile phone text messaging.
The lifetime incremental costs and benefits of adding text-based support to current practice are estimated from a UK NHS perspective using a Markov model. The cost-effectiveness was measured in terms of cost per quitter, cost per life year gained and cost per QALY gained. As in previous studies, smokers are assumed to face a higher risk of experiencing the following five diseases: lung cancer, stroke, myocardial infarction, chronic obstructive pulmonary disease, and coronary heart disease (i.e. the main fatal or disabling, but by no means the only, adverse effects of prolonged smoking). The treatment costs and health state values associated with these diseases were identified from the literature. The analysis was based on the age and gender distribution observed in the txt2stop trial. Effectiveness and cost parameters were varied in deterministic sensitivity analyses, and a probabilistic sensitivity analysis was also performed.
The cost of text-based support per 1,000 enrolled smokers is £16,120, which, given an estimated 58 additional quitters at 6 months, equates to £278 per quitter. However, when the future NHS costs saved (as a result of reduced smoking) are included, text-based support would be cost saving. It is estimated that 18 LYs are gained per 1,000 smokers (0.3 LYs per quitter) receiving text-based support, and 29 QALYs are gained (0.5 QALYs per quitter). The deterministic sensitivity analysis indicated that changes in individual model parameters did not alter the conclusion that this is a cost-effective intervention. Similarly, the probabilistic sensitivity analysis indicated a >90 % chance that the intervention will be cost saving.
This study shows that under a wide variety of conditions, personalised smoking cessation advice and support by mobile phone message is both beneficial for health and cost saving to a health system.
Smoking cessation aid; Economic evaluation; Text message; I18
We report here the identification and characterization of two zinc uptake systems, ZurAM and ZinABC, in the intracellular pathogen Listeria monocytogenes. Transcription of both operons was zinc responsive and regulated by the zinc-sensing repressor Zur. Deletion of either zurAM or zinA had no detectable effect on growth in defined media, but a double zurAM zinA mutant was unable to grow in the absence of zinc supplementation. Deletion of zinA had no detectable effect on intracellular growth in HeLa epithelial cells. In contrast, growth of the zurAM mutant was significantly impaired in these cells, indicating the importance of the ZurAM system during intracellular growth. Notably, the deletion of both zinA and zurAM severely attenuated intracellular growth, with the double mutant being defective in actin-based motility and unable to spread from cell to cell. Deletion of either zurAM or zinA had a significant effect on virulence in an oral mouse model, indicating that both zinc uptake systems are important in vivo and establishing the importance of zinc acquisition during infection by L. monocytogenes. The presence of two zinc uptake systems may offer a mechanism by which L. monocytogenes can respond to zinc deficiency within a variety of environments and during different stages of infection, with each system making distinct contributions under different stress conditions.
Worldwide, over 10 million people are killed or hospitalized because of traumatic brain injury each year. About 90% of deaths occur in low- and middle-income countries. The condition mostly affects young adults, and many experience long lasting or permanent disability. The social and economic burden is considerable. Tranexamic acid (TXA) is commonly given to surgical patients to reduce bleeding and the need for blood transfusion. It has been shown to reduce the number of patients receiving a blood transfusion by about a third, reduces the volume of blood transfused by about one unit, and halves the need for further surgery to control bleeding in elective surgical patients.
The CRASH-3 trial is an international, multicenter, pragmatic, randomized, double-blind, placebo-controlled trial to quantify the effects of the early administration of TXA on death and disability in patients with traumatic brain injury. Ten thousand adult patients who fulfil the eligibility criteria will be randomized to receive TXA or placebo. Adults with traumatic brain injury, who are within 8 h of injury and have any intracranial bleeding on computerized tomography (CT scan) or Glasgow Coma Score (GCS) of 12 or less can be included if the responsible doctor is substantially uncertain as to whether or not to use TXA in this patient. Patients with significant extracranial bleeding will be excluded since there is evidence that TXA improves outcome in these patients. Treatment will entail a 1 g loading dose followed by a 1 g maintenance dose over 8 h.
The main analyses will be on an ‘intention-to-treat’ basis, irrespective of whether the allocated treatment was received. Results will be presented as appropriate effect estimates with a measure of precision (95% confidence intervals). Subgroup analyses for the primary outcome will be based on time from injury to randomization, the severity of the injury, location of the bleeding, and baseline risk. Interaction tests will be used to test whether the effect of treatment differs across these subgroups. A study with 10,000 patients will have approximately 90% power to detect a 15% relative reduction from 20% to 17% in all-cause mortality.
Current Controlled Trials ISRCTN15088122; Clinicaltrials.gov NCT01402882
Antifibrinolytic; Clinical trial; Emergency care; Intracranial bleeding; Tranexamic acid; Traumatic brain injury
The energy requirement of species at each trophic level in an ecological pyramid is a function of the number of organisms and their average mass. Regarding human populations, although considerable attention is given to estimating the number of people, much less is given to estimating average mass, despite evidence that average body mass is increasing. We estimate global human biomass, its distribution by region and the proportion of biomass due to overweight and obesity.
For each country we used data on body mass index (BMI) and height distribution to estimate average adult body mass. We calculated total biomass as the product of population size and average body mass. We estimated the percentage of the population that is overweight (BMI > 25) and obese (BMI > 30) and the biomass due to overweight and obesity.
In 2005, global adult human biomass was approximately 287 million tonnes, of which 15 million tonnes were due to overweight (BMI > 25), a mass equivalent to that of 242 million people of average body mass (5% of global human biomass). Biomass due to obesity was 3.5 million tonnes, the mass equivalent of 56 million people of average body mass (1.2% of human biomass). North America has 6% of the world population but 34% of biomass due to obesity. Asia has 61% of the world population but 13% of biomass due to obesity. One tonne of human biomass corresponds to approximately 12 adults in North America and 17 adults in Asia. If all countries had the BMI distribution of the USA, the increase in human biomass of 58 million tonnes would be equivalent in mass to an extra 935 million people of average body mass, and have energy requirements equivalent to that of 473 million adults.
Increasing population fatness could have the same implications for world food energy demands as an extra half a billion people living on the earth.
The genome sequences of enterohaemorrhagic E. coli O157:H7 strains show multiple open-reading frames with collagen-like sequences that are absent from the common laboratory strain K-12. These putative collagens are included in prophages embedded in O157:H7 genomes. These prophages carry numerous genes related to strain virulence and have been shown to be inducible and capable of disseminating virulence factors by horizontal gene transfer. We have cloned two collagen-like proteins from E. coli O157:H7 into a laboratory strain and analysed the structure and conformation of the recombinant proteins and several of their constituting domains by a variety of spectroscopic, biophysical, and electron microscopy techniques. We show that these molecules exhibit many of the characteristics of vertebrate collagens, including trimer formation and the presence of a collagen triple helical domain. They also contain a C-terminal trimerization domain, and a trimeric α-helical coiled-coil domain with an unusual amino acid sequence almost completely lacking leucine, valine or isoleucine residues. Intriguingly, these molecules show high thermal stability, with the collagen domain being more stable than those of vertebrate fibrillar collagens, which are much longer and post-translationally modified. Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk. This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins. Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.
Some national guidelines recommend the use of water alone for napkin cleansing. Yet, there is a readiness, amongst many parents, to use baby wipes. Evidence from randomised controlled trials, of the effect of baby wipes on newborn skin integrity is lacking. We conducted a study to examine the hypothesis that the use of a specifically formulated cleansing wipe on the napkin area of newborn infants (<1 month) has an equivalent effect on skin hydration when compared with using cotton wool and water (usual care).
A prospective, assessor-blinded, randomised controlled equivalence trial was conducted during 2010. Healthy, term babies (n = 280), recruited within 48 hours of birth, were randomly assigned to have their napkin area cleansed with an alcohol-free baby wipe (140 babies) or cotton wool and water (140 babies). Primary outcome was change in hydration from within 48 hours of birth to 4 weeks post-birth. Secondary outcomes comprised changes in trans-epidermal water loss, skin surface pH and erythema, presence of microbial skin contaminants/irritants at 4 weeks and napkin dermatitis reported by midwife at 4 weeks and mother during the 4 weeks.
Complete hydration data were obtained for 254 (90.7 %) babies. Wipes were shown to be equivalent to water and cotton wool in terms of skin hydration (intention-to-treat analysis: wipes 65.4 (SD 12.4) vs. water 63.5 (14.2), p = 0.47, 95 % CI -2.5 to 4.2; per protocol analysis: wipes 64.6 (12.4) vs. water 63.6 (14.3), p = 0.53, 95 % CI -2.4 to 4.2). No significant differences were found in the secondary outcomes, except for maternal-reported napkin dermatitis, which was higher in the water group (p = 0.025 for complete responses).
Baby wipes had an equivalent effect on skin hydration when compared with cotton wool and water. We found no evidence of any adverse effects of using these wipes. These findings offer reassurance to parents who choose to use baby wipes and to health professionals who support their use.
Current Controlled Trials ISRCTN86207019
Listeria monocytogenes is a Gram-positive facultative intracellular bacterium responsible for the food borne infection listeriosis, affecting principally the immunocompromised, the old, neonates and pregnant women. Following invasion L. monocytogenes escapes the phagosome and replicates in the cytoplasm. Phagosome escape is central to L. monocytogenes virulence and is required for initiating innate host-defence responses such as the secretion of the cytokine interleukin-1. Phagosome escape of L. monocytogenes is reported to depend upon host proteins such as γ-interferon-inducible lysosomal thiol reductase and the cystic fibrosis transmembrane conductance regulator. The host cytosolic cysteine protease calpain is required in the life cycle of numerous pathogens, and previous research reports an activation of calpain by L. monocytogenes infection. Thus we sought to determine whether host calpain was required for the virulence of L. monocytogenes. Treatment of macrophages with calpain inhibitors blocked escape of L. monocytogenes from the phagosome and consequently its proliferation within the cytosol. This was independent of any direct effect on the production of bacterial virulence factors or of a bactericidal effect. Furthermore, the secretion of interleukin-1β, a host cytokine whose secretion induced by L. monocytogenes depends upon phagosome escape, was also blocked by calpain inhibition. These data indicate that L. monocytogenes co-opts host calpain to facilitate its escape from the phagosome, and more generally, that calpain may represent a cellular Achilles heel exploited by pathogens.
The CRASH-2 trial showed that early administration of tranexamic acid (TXA) safely reduces mortality in bleeding in trauma patients. Based on data from the CRASH-2 trial, global mortality data and a systematic literature review, we estimated the number of premature deaths that might be averted every year worldwide through the use of TXA.
We used CRASH-2 trial data to examine the effect of TXA on death due to bleeding by geographical region. We used WHO mortality data (2008) and data from a systematic review of the literature to estimate the annual number of in-hospital trauma deaths due to bleeding. We then used the relative risk estimates from the CRASH-2 trial to estimate the number of premature deaths that could be averted if all hospitalised bleeding trauma patients received TXA within one hour of injury, and within three hours of injury. Sensitivity analyses were used to explore the effect of uncertainty in the parameter estimates and the assumptions made in the model.
There is no evidence that the effect of TXA on death due to bleeding varies by geographical region (heterogeneity p = 0.70). Based on WHO data and our systematic literature review, we estimate that each year worldwide there are approximately 400,000 in-hospital trauma deaths due to bleeding. If patients received TXA within one hour of injury then approximately 128,000 (uncertainty range [UR] ≈ 72,000 to 172,000) deaths might be averted. If patients received TXA within three hours of injury then approximately 112,000 (UR ≈ 68,000 to 148,000) deaths might be averted. Country specific estimates show that the largest numbers of deaths averted would be in India and China.
The use of TXA in the treatment of traumatic bleeding has the potential to prevent many premature deaths every year. A large proportion of the potential health gains are in low and middle income countries.
Public objection to autopsy has led to a search for minimally invasive alternatives. Imaging has potential, but its accuracy is unknown. We aimed to identify the accuracy of post-mortem CT and MRI compared with full autopsy in a large series of adult deaths.
This study was undertaken at two UK centres in Manchester and Oxford between April, 2006, and November, 2008. We used whole-body CT and MRI followed by full autopsy to investigate a series of adult deaths that were reported to the coroner. CT and MRI scans were reported independently, each by two radiologists who were masked to the autopsy findings. All four radiologists then produced a consensus report based on both techniques, recorded their confidence in cause of death, and identified whether autopsy was needed.
We assessed 182 unselected cases. The major discrepancy rate between cause of death identified by radiology and autopsy was 32% (95% CI 26–40) for CT, 43% (36–50) for MRI, and 30% (24–37) for the consensus radiology report; 10% (3–17) lower for CT than for MRI. Radiologists indicated that autopsy was not needed in 62 (34%; 95% CI 28–41) of 182 cases for CT reports, 76 (42%; 35–49) of 182 cases for MRI reports, and 88 (48%; 41–56) of 182 cases for consensus reports. Of these cases, the major discrepancy rate compared with autopsy was 16% (95% CI 9–27), 21% (13–32), and 16% (10–25), respectively, which is significantly lower (p<0·0001) than for cases with no definite cause of death. The most common imaging errors in identification of cause of death were ischaemic heart disease (n=27), pulmonary embolism (11), pneumonia (13), and intra-abdominal lesions (16).
We found that, compared with traditional autopsy, CT was a more accurate imaging technique than MRI for providing a cause of death. The error rate when radiologists provided a confident cause of death was similar to that for clinical death certificates, and could therefore be acceptable for medicolegal purposes. However, common causes of sudden death are frequently missed on CT and MRI, and, unless these weaknesses are addressed, systematic errors in mortality statistics would result if imaging were to replace conventional autopsy.
Policy Research Programme, Department of Health, UK.
The fission yeast Schizosaccharomyces pombe has been widely used to study eukaryotic cell biology, but almost all of this work has used derivatives of a single strain. We have studied 81 independent natural isolates and 3 designated laboratory strains of Schizosaccharomyces pombe. Schizosaccharomyces pombe varies significantly in size but shows only limited variation in proliferation in different environments compared with Saccharomyces cerevisiae. Nucleotide diversity, π, at a near neutral site, the central core of the centromere of chromosome II is approximately 0.7%. Approximately 20% of the isolates showed karyotypic rearrangements as detected by pulsed field gel electrophoresis and filter hybridization analysis. One translocation, found in 6 different isolates, including the type strain, has a geographically widespread distribution and a unique haplotype and may be a marker of an incipient speciation event. All of the other translocations are unique. Exploitation of this karyotypic diversity may cast new light on both the biology of telomeres and centromeres and on isolating mechanisms in single-celled eukaryotes.
pombe; karyotype; diversity; fission yeast