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Context. Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are the most important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a direct comparison with observational data. Aims. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. Methods. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a millimetre VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects, compared to the addition of thermal noise only. Using synthetic data based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M 87, we performed case studies to assess the image quality that can be obtained with the current and future EHT array for different weather conditions. Results. Our synthetic observations show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of our GRMHD source models can be recovered robustly with the EHT2017 array after performing calibration steps, which include fringe fitting, a priori amplitude and network calibration, and self-calibration. With the planned addition of new stations to the EHT array in the coming years, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images. © 2020 ESO., This work is supported by the ERC Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (Grant 610058). I. Natarajan and R. Deane are grateful for the support from the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa. The authors of the present paper further thank the following organizations and programmes: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comision Nacional de Investigacio Cientifica y Tecnologica (CONICYT, Chile, via PIA ACT172033, Fondecyt 1171506, BASAL AFB-170002, ALMAconicyt 31140007); Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Direccion General de Asuntos del Personal Academico-Universidad Nacional Autonoma de Mexico (DGAPA-UNAM, project IN112417); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177; the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the GenT Program (Generalitat Valenciana) under project CIDEGENT/2018/021; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJ-SSW-SLH057, QYZDJ-SSW-SYS008); the Leverhulme Trust Early Career Research Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119-M-001027, 107-2119-M-001-017, 107-2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649); NASA through the NASA Hubble Fellowship grant #HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. , for NASA, under contract NAS5-26555; the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1312651, AST-1337663, AST-1440254, AST-1555365, AST-1715061, AST-1615796, AST-1716327, OISE-1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11933007); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, 2015-R1D1A1A01056807, the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Princeton/Flatiron Postdoctoral Prize Fellowship; the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economia y Competitividad (grants AYA2015-63939-C21-P, AYA2016-80889-P); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell'Istruzione Universita e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Union's Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; the Academia Sinica; Chandra TM6-17006X. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI1743442. XSEDE Stampede2 resource at TACC was allocated through TGAST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario.ca), Calcul Quebec (http://www. calculquebec.ca) and Compute Canada (http://www.computecanada.ca).We thank the sta ff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2017.1.00841.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. APEX is a collaboration between the Max-Planck-Institut fur Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key R&D Program (No. 2017YFA0402700) of China. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrofisica, Optica, y Electronica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany) and IGN (Instituto Geografico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. The SPT is supported by the National Science Foundation through grant PLR-1248097. Partial support is also provided by the NSF Physics Frontier Center grant PHY-1125897 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation and the Gordon and Betty Moore Foundation grant GBMF 947. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended staff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are located, has for the indigenous Hawaiian people. The software presented in this work makes use of the Numpy (van derWalt et al. 2011), Scipy (Jones et al. 2001), Astropy (Astropy Collaboration 2013, 2018) libraries and the KERN software bundle (Molenaar & Smirnov 2018).

The relationship between socioeconomic status (SES) and inflammatory bowel disease (IBD) is controversial. To date, research has focused on effects on incidence and prevalence, disease management and clinical outcomes; however, conclusions remain uncertain. This review examines current evidence, identifies what remains to be understood and explores the practical implications this has for today. A structured literature search in Ovid, Medline, the Cochrane library, Google Scholar and clinicaltrials.gov was performed using defined key words, including all articles up until 5 October 2016 assessing SES as a primary or secondary outcome measure. Twenty-one studies were identified, investigating incidence and prevalence (n=13), disease outcomes (n=5) and mortality (n=3). Data linking SES with IBD incidence are conflicting, with studies citing both positive and negative trends. Patients with low SES, particularly those with Crohn's disease, show higher rates of hospitalization, service usage and IBD-associated mortality. On the basis of the available study data, it is difficult to relate SES with the risk of IBD. For Crohn's disease, in particular, the link between deprivation and increased hospitalization and mortality observed from world-wide studies is alarming. It seems most likely that the cause links to well-documented behavioural, materialistic, psychosocial and life-course models used to explain social class inequalities in other diseases.

BackgroundCardiopulmonary exercise testing helps prognosticate and guide treatment in adults with pulmonary hypertension. Concerns regarding its feasibility and safety limit its use in children with pulmonary hypertension. We aimed to assess the feasibility and safety of cardiopulmonary exercise testing in a large paediatric pulmonary hypertension cohort.MethodsWe reviewed all consecutive cardiopulmonary exercise tests performed between March, 2004 and November, 2013. The exclusion criteria were as follows: height 2 saturation.ResultsA total of 98 children underwent 167 cardiopulmonary exercise tests. The median age was 14 years (inter-quartile range 10–15 years). Peak oxygen uptake was 20.4±7.3 ml/kg/minute, corresponding to 51.8±18.3% of the predicted value. Peak respiratory quotient was 1.08±0.16. All the tests except two were maximal, being terminated prematurely for clinical reasons. Baseline Oxygen saturation was 93.3±8.8% and was 81.2±19.5% at peak exercise. A drop in arterial O2 saturation >20% was observed in 23.5% of the patients. Moreover, five patients (3.0%) experienced dizziness, one requiring termination of cardiopulmonary exercise testing; five children (3.0%) experienced chest pain, with early cardiopulmonary exercise test termination in one patient. No significant arrhythmias or electrocardiogram changes were observed.ConclusionExercise testing in non-severely symptomatic children with pulmonary hypertension is safe and practical, and can be performed in a large number of children with pulmonary hypertension in a controlled environment with an experienced team. Side-effects were not serious and were resolved promptly with test termination.

BACKGROUND: Heart rate variability (HRV) analysis is uncommonly undertaken in patients with atrial fibrillation (AF) due to an assumption that ventricular response is random. We sought to determine the effects of head-up tilt (HUT), a stimulus known to elicit an autonomic response, on HRV in patients with AF; we contrasted the findings with those of patients in sinus rhythm (SR). METHODS: Consecutive, clinically indicated tilt tests were examined for 207 patients: 176 in SR, 31 in AF. Patients in AF were compared to an age-matched SR cohort (n = 69). Five minute windows immediately before and after tilting were analyzed using time-domain, frequency-domain and nonlinear HRV parameters. Continuous, noninvasive assessment of blood pressure, heart rate and stroke volume were available in the majority of patients. RESULTS: There were significant differences at baseline in all HRV parameters between AF and age matched SR. HUT produced significant hemodynamic changes, regardless of cardiac rhythm. Coincident with these hemodynamic changes, patients in AF had a significant increase in median [quartile 1, 2] DFA-α2 (+0.14 [-0.03, 0.32], p

Background Kawasaki disease (KD), or mucocutaneous syndrome, is the leading cause of childhood-acquired heart disease in the developed world. There is much controversy on how best to treat children with KD and in particular who may benefit from additional treatment beyond the standard intravenous immunoglobulin (IVIG) and aspirin, such as the addition of corticosteroids. Objectives To assess the impact of corticosteroid use on the incidence of coronary artery abnormalities in KD as either first-line or second-line treatment. Corticosteroids may be given alone or in conjunction with other accepted KD treatments. Secondary objectives include the effect of steroids on mortality, the time taken for laboratory parameters to normalise, the duration of acute symptoms (such as fever), the long-term impact of steroid use and evaluating their safety in KD and their efficacy in relevant population subgroups. Search methods The Cochrane Vascular Information Specialist searched Cochrane Vascular's Specialised Register (25 November 2016) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 10) in the Cochrane Library (searched 25 November 2016). Trial registries were also searched for details of ongoing or unpublished studies. Selection criteria We selected randomised trials involving children with all severities of KD who were treated with corticosteroids, including different types of corticosteroid and different durations of treatment. Data collection and analysis MJS and GMC independently selected studies, assessed evidence quality and extracted data. This process was overseen by AJW. Main results Seven trials consisting of 922 participants were included in this analysis. Trials ranged from 32 to 242 participants. On pooled analysis, corticosteroids reduced the subsequent occurrence of coronary artery abnormalities (odds ratio (OR) 0.29, 95% confidence interval (CI) 0.18 to 0.46; 907 participants; 7 studies; I² = 55%) without resultant serious adverse events (no events, 737 participants) and mortality (no events, 915 participants). In addition, corticosteroids reduced the duration of fever (mean difference (MD) −1.65 days, 95% CI −3.31 to 0.00; 210 participants; 2 studies; I² = 88%), time for laboratory parameters (erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)) to normalise (MD −2.80 days, 95% CI −4.38 to −1.22; 178 participants; 1 study) and length of hospital stay (MD −1.41 days, 95% CI −2.36 to −0.46; 39 participants; 1 study). No studies detailed outcomes beyond 24 weeks. Subgroup analysis showed some potential groups that may benefit more than others; however, further randomised controlled trials are required before this can be the basis for clinical action. Evidence quality was graded according to the GRADE system. Evidence was considered high quality for the incidence of serious adverse events, mortality and time for laboratory parameters to normalise. Evidence was considered moderate for the incidence of coronary artery abnormalities due to potential inconsistencies in data geography and patient benefits according to grouping. Evidence was moderate for duration of clinical symptoms (fever, rash) due to potential subjectivity in measurement. Evidence was moderate for length of hospital stay as only one study recorded this outcome. This means that we are reasonably confident that the true effect is close to that estimated in this work. Authors' conclusions Moderate-quality evidence shows that use of steroids in the acute phase of KD can be associated with improved coronary artery abnormalities, shorter duration of hospital stay and a decreased duration of clinical symptoms. High-quality evidence shows reduced inflammatory marker levels. There were insufficient data available regarding incidence of adverse effects attributable to steroids, mortality and long-term (> 1 year) coronary morbidity. Certain groups, including those based in Asia, those with higher risk scores, and those receiving longer steroid treatment may have greater benefit from steroid use, especially with decreasing rates of heart problems, but more tests are needed to answer these questions. Evidence presented in this study suggests that treatment with a long course of steroids should be considered for all children diagnosed with KD until further studies are performed.

In recent times, paediatric pulmonary arterial hypertension management has been transformed to focus on disease modifying strategies that improve both quality of life and survival, rather than just symptom palliation. Sildenafil, a phosphodiesterase-V inhibitor, has been at the centre of this. Despite controversial beginnings, its success in treating pulmonary arterial hypertension has led to its consideration for related pathologies such as persistent pulmonary hypertension of the newborn and bronchopulmonary dysplasia, as well as the development of a range of alternative formulations. However, this has caused its own controversy and confusion regarding the use of sildenafil in younger patients. In addition, recent data regarding long-term mortality and the repeal of US drugs approval have complicated the issue. Despite such setbacks, sildenafil continues to be a major component of the contemporary care of paediatric pulmonary hypertension in a variety of contexts, and this does not seem likely to change in the foreseeable future.

Known single-nucleotide polymorphisms (SNPs) explain 50% heritability from twin and family studies, a phenomenon termed ‘missing heritability’. Using DNA alone for unrelated individuals, a novel method (in a software package called Genome-wide Complex Trait Analysis, GCTA) estimates the total additive genetic influence due to common SNPs on whole-genome arrays. GCTA has made major inroads into explaining the ‘missing heritability’ of BMI in adults. This study provides the first GCTA estimate of genetic influence on adiposity in children. Participants were from the Twins Early Development Study (TEDS), a British twin birth cohort. BMI s.d. scores (BMI-SDS) were obtained from validated parent-reported anthropometric measures when children were about 10 years old (mean=9.9; s.d.=0.84). Selecting one child per family (n=2269), GCTA results from 1.7 million DNA markers were used to quantify the additive genetic influence of common SNPs. For direct comparison, a standard twin analysis in the same families estimated the additive genetic influence as 82% (95% CI: 0.74–0.88, P

Background Pulmonary hypertension is a condition of complex aetiology that culminates in right heart failure and early death. Soluble guanylate cyclase (sGC) stimulators are a promising class of agents that have recently gained approval for use. Objectives To evaluate the efficacy of sGC stimulators in pulmonary hypertension. Search methods We searched CENTRAL (Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE and the reference lists of articles. Searches are current as of 12 February 2016. Selection criteria We selected randomised controlled trials (RCTs) involving participants with pulmonary hypertension of all ages, severities and durations of treatment. Data collection and analysis AW, MS and RW independently selected studies, assessed evidence quality and extracted data. This process was overseen by RT and SG. All included studies were sponsored by the drug manufacturer. Main results Five trials involving 962 participants are included in this review. All trials were of relatively short duration (< 16 weeks). Due to the heterogenous aetiology of pulmonary hypertension in participants, results are best considered according to each pulmonary hypertension subtype. Pooled analysis shows a mean difference (MD) increase in six-minute walking distance (6MWD) of 30.13 metres (95% CI 5.29 to 54.96; participants = 659; studies = 3). On subgroup analysis, for pulmonary arterial hypertension (PAH) there was no effect noted (6MWD; MD 11.91 metres, 95% CI −44.92 to 68.75; participants = 398; studies = 2), and in chronic thromboembolic pulmonary hypertension (CTEPH) sGC stimulators improved 6MWD by an MD of 45 metres (95% CI 23.87 to 66.13; participants = 261; studies = 1). Data for left heart disease-associated PH was not available for pooling. Importantly, when participants receiving phosphodiesterase inhibitors were excluded, sGC stimulators increased 6MWD by a MD of 36 metres in PAH. The second primary outcome, mortality, showed no change on pooled analysis against placebo (Peto odds ratio (OR) 0.57, 95% CI 0.18 to 1.80). Pooled secondary outcomes include an increase in World Health Organization (WHO) functional class (OR 1.53, 95% CI 0.87 to 2.72; participants = 858; studies = 4), no effect on clinical worsening (OR 0.45, 95% CI 0.17 to 1.14; participants = 842; studies = 3), and a reduction in mean pulmonary artery pressure (MD −2.77 mmHg, 95% CI −4.96 to −0.58; participants = 744; studies = 5). There was no significant difference in serious adverse events on pooled analysis (OR 1.12, 95% CI 0.66 to 1.90; participants = 818; studies = 5) or when analysed at PAH (MD −3.50, 95% CI −5.54 to −1.46; participants = 344; studies = 1), left heart disease associated subgroups (OR 1.56, 95% CI 0.78 to 3.13; participants = 159; studies = 2) or CTEPH subgroups (OR 1.29, 95% CI 0.65 to 2.56; participants = 261; studies = 1). It is important to consider the results for PAH in the context of a person who is not also receiving a phosphodiesterase-V inhibitor, a contra-indication to sGC stimulator use. It should also be noted that CTEPH results are applicable to inoperable or recurrent CTEPH only. Evidence was rated according to the GRADE scoring system. One outcome was considered high quality, two were moderate, and eight were of low or very low quality, meaning that for many of the outcomes the true effect could differ substantially from our estimate. There were only minor concerns regarding the risk of bias in these trials, all being RCTs largely following the original protocol. Most trials employed an intention-to-treat analysis. Authors' conclusions sGC stimulators improve pulmonary artery pressures in people with PAH (who are treatment naive or receiving a prostanoid or endothelin antagonist) or those with recurrent or inoperable CTEPH. In these settings this can be achieved without notable complication. However, sGC stimulators should not be taken by people also receiving phosphodiestase-V inhibitors or nitrates due to the risks of hypotension, and there is currently no evidence supporting their use in pulmonary hypertension associated with left heart disease. There is no evidence supporting their use in children. These conclusions are based on data with limitations, including unavailable data from two of the trials.

Monocrotaline (MCT) is a naturally occurring hepatotoxic pyrrolizidine alkaloid found in plants. This investigation is aimed at furthering the understanding of the role of blood in mediating the transport of MCT and its reactive metabolites in humans. Reactions of monocrotaline and its metabolites, dehydromonocrotaline (DHM), retronecine (RET) and dehydroretronecine (DHR) with human blood plasma, red blood cells (RBCs), and whole blood were studied in vitro by proton nuclear magnetic resonance spectroscopy. In plasma MCT remained intact and weakly associated with plasma proteins, and DHM was rapidly hydrolyzed releasing necic and lactone acids, and the reactive pyrrolic metabolite. MCT and its metabolite DHM were internalized in RBCs to the extent of 46.0% and 48.9% respectively in 30 min. No polymerization of DHR was observed when incubated with plasma and RBCs. The data clearly showed that both human plasma and RBCs could be the carriers for the transportation of MCT and its metabolites, DHM, RET and DHR between organs and could stabilise the reactive MCT metabolite DHR.

We show in this work that disruption of the hfq gene in Escherichia coli causes a large increase in IS10 transposition when IS10 is present on a multi-copy plasmid. Hfq is an RNA-binding protein that regulates the expression of a large number of genes at the post-transcriptional level by promoting the pairing of mRNAs with partially complementary short RNAs. As the translation of IS10 transposase mRNA (RNA-IN) is inhibited by an IS10-encoded anti-sense RNA (RNA-OUT), it seemed likely that Hfq would negatively regulate Tn10/IS10 transposition by promoting anti-sense inhibition of RNA-IN translation. Consistent with this, we show that Hfq promotes pairing of RNA-IN and RNA-OUT in vitro and downregulates RNA-IN expression in vivo. However, we also show that Hfq negatively regulates Tn10 transposition when no functional anti-sense RNA is produced. Taken together, the results suggest that Hfq acts at two distinct steps to inhibit Tn10/IS10 transposition. This is the first example of Hfq regulating a bacterial transposition reaction.

The development of O-phosphotyrosine (pTyr) analogues is reviewed, along with their application in peptidomimetic ligands to proteins implicated in disease-states arising from dysfunctional intracellular signal transduction pathways. Salient features of chemical syntheses are critiqued, including those of established mimetics such as 4'-(phosphonomethyl)phenylalanine (Pmp), 4'- (phosphono)phenylalanine (Ppp) and 4'-(phosphonodifluoromethyl)phenylalanine (F2Pmp), their respective (?-methyl)phenylalanine analogues and “preorganised” side-chain cyclised pTyr mimetics. Syntheses of 4'-(phosphinomethyl)phenylalanines are also described, as are “bone-directing” residues such as 4'-(diphosphonomethyl)phenylalanine (dpmF), 3',4'-(diphosphono)phenylalanine and 4'- carboxymethyloxy-3'-(phosphono)phenylalanine (CPP), capable of eliciting additional interactions with pTyr-binding subsites of specified proteins. The utility of [(4'-phosphonomethyl)phenyl]propenoic acid in current developments is also discussed as a route to a range of ?- and ?-substituted pTyr mimetics, and to pTyr mimetics bearing the requisite ?-vinyl functionality to facilitate macrocyclisation via olefin metathesis - of interest in the development of structures exhibiting global conformational constraint. Finally, developments in prodrug presentation of pTyr mimetics are also discussed.

Background: The use of complementary and alternative medicine has attracted much attention and debate in recent years. The objective of this critical review is to examine the evidence base on use of complementary products and therapies during pregnancy. It examines an important but neglected issue in maternity care. Methods: A database search was conducted in MEDLINE, CINAHL, AMED, and Maternity and Infant Care. A total of 24 papers published between 1999 and 2008 met the selection criteria and were included in the review. Results: Findings of these 24 papers were extracted and reported under four themes: "user prevalence and profile," "motivation and condition of use," "perception and self-reported evaluation," and "referral and information sources." Conclusions: This review highlights four research gaps in the literature, a lack of: large representative samples; in-depth understanding of user experiences and risk perceptions; research comparing consumption patterns across cultures and over time; and work exploring the nature of the therapeutic encounter with complementary practitioners in this area of women's health care. © 2009, Wiley Periodicals, Inc.

Research (1970–1975) on oyster culture utilizing a petroleum platform six kilometers offshore from High Island, Texas is summarized. Growth of oysters held offshore was comparable to that of oysters held in the estuary. Growth of oysters offshore was equal to depths of eight meters. Growth of juvenile oysters in terms of length was less for oysters held in wire trays compared to plastic mesh bags and less for oysters from which fouling was removed monthly compared to oysters not brushed to remove fouling. Oysters suspended during the fall showed best condition during the following June and estuarine oysters were in better condition than offshore oysters. Mortality of oysters infected with the fungus Labyrinthomyxa marina was high (30–65%), while mortality of uninfected oysters was low (0–29%) both offshore and in the estuary. Oyster loses were primarily attributed to vandalism in the estuary and mechanical failure offshore. Oysters from the bay completely depurated fecal coliforms within seven days after transfer offshore. Oysters cultured offshore were found to be as acceptable as oysters from the bay in an organoleptic evaluation by a ten member panel.

Literature publications reporting the development of organophosphorus compounds, targeting aspects of signal transduction to the titled therapeutic ends, are reviewed. With respect to extracellular targets, the development of ligands to purinergic (P2), and endothelial differentiation-gene receptors (of S1P- and LPA-receptor subtypes) is charted, along with inhibitors of the production and release of tumour necrosis factor-alpha (TNF-alpha). Reported also are inhibitors of the ectoenzymes aminopeptidase N, aminopeptidase A and dipeptidyl peptidase IV, the proteolytic enzyme thrombin, ligands to "apoptosis-receptors" and gammadelta T-cell activators. In addition, disruption of intracellular signalling chains mediated through reversible coupling of proteins via phosphorylation of Tyr residues and docking of pTyr residues in SH2-binding domains is covered. In particular, the development of ligands to SH2-binding domains in tyrosine kinases Src and lck, adaptor protein Grb2, and also ZAP70 protein are reported along with inhibitors to relevant phosphatases. SAR studies of ligands to Ins(1,4,5)-P3- and ryanodine-type receptors of intracellular Ca2+-storage organelles are described including analogues to secondary messengers cyclic-ADP-ribose (cADPR) and myo-inositol-1,4,5-triphosphate. Inhibitors of phosphatidyl inositol 3-kinase (PI3K) and sphingomyelinase are also reported, as are inhibitors of farnesyl transferase, the enzyme involved in protein-prenylation.

The haemiglobincyanide (HiCN) method for measuring haemoglobin is used extensively worldwide; its advantage is the ready availability of a stable and internationally accepted reference standard/calibrator. However, its use may create a problem, especially in automated analysers, as the waste disposal of large volumes of reagent containing cyanide may constitute a potential toxic hazard. As an alternative, conversion of haemoglobin to a sulphate derivative by nontoxic sodium lauryl sulphate has been proposed and is available as a commercial product from Toa Medical Electronics Co. Ltd., Japan. This evaluation has shown it to be as reliable and reproducible as HiCN for measuring haemoglobin at all concentrations, by both spectrophotometry and automated analyser. Maximum absorbance is at 534 nm. Total conversion occurs almost instantaneously, and includes methaemoglobin but not sulphaemoglobin. HbF is also measured. The only disadvantage is that solutions of haemoglobin-sulphate are stable for only a few hours at room temperature and up to three weeks at 4 degrees C. Thus, for standardization and calibration of instruments it is necessary to use a sample of blood or lysate the haemoglobin value of which has been assigned initially by the HiCN method.

Dissemination of the bacterial transposon Tn10 is limited by target site channeling, a process wherein the transposon ends are forced to interact with and insert into a target site located within the transposon. Integration host factor (IHF) promotes this self-destructive event by binding to the transpososome and forming a DNA loop close to one or both transposon ends; this loop imposes geometric and topological constraints that are responsible for channeling. We demonstrate that a second 'host' protein, histone-like nucleoid structuring protein (H-NS), acts as an anti-channeling factor to limit self-destructive intramolecular transposition events in vitro. Evidence that H-NS competes with IHF for binding to the Tn10 transpososome to block channeling and that this event is relatively insensitive to the level of DNA supercoiling present in the Tn10-containing substrate plasmid are presented. This latter observation is atypical for H-NS, as H-NS binding to other DNA sequences, such as promoters, is generally affected by subtle changes in DNA structure.

Literature publications (up to September 2006) concerning the synthesis of ?-phosphinyl-?-amino acids and their development towards use as therapeutic agents are reviewed. General and asymmetric methodologies for the preparation of straight-chain examples are described, including AP3-7 modulators of glutamate-responsive excitatory amino acid (EAA) receptors (i.e. ionotropic NMDA-, and metabotropic GrpIII mGlu-receptors), and the glutamate synthetase inhibitor phosphinothricin. Focusing primarily on the development of methods for introducing phosphonate and aminocarboxylate functions to the appropriate scaffold, approaches to conformationally constrained ?-phosphinyl-?-amino acids are also investigated, along with their relevance to the development of therapeutic regimens towards neurodegenerative disorders.

The multiple steps of DNA transposition take place within a large complex called the transpososome, in which a pair of transposon DNA ends are synapsed by a multimer of the transposase protein. The final step, a DNA strand transfer reaction that joins the transposon ends to the target DNA strands, entails no net change in the number of high-energy chemical bonds. Physiology demands that, despite remaining stably associated with the transpososome, the strand transfer products undergo neither the reverse reaction nor any further cleavage reactions. Accordingly, when the Mu or Tn10 strand transfer complex was produced in vitro through transposase-catalyzed reaction steps, reverse reactions were undetectable. In contrast, when the Mu or Tn10 strand transfer complexes were assembled from DNA already having the structure of the strand transfer product, we detected a reaction that resembled reversal of target DNA strand transfer. The stereoselectivity of phosphorothioate-containing substrates indicated that this reaction proceeds as the pseudoreversal of the normal target DNA strand transfer step. Comparison of the reactivity of closely related Mu substrate DNA structures indicated that the configuration of the flanking DNA outside of the transposon sequence plays a key role in preventing the transposon end cleavage reaction after the strand transfer step.

A new synthetic pathway to 1-(2-[beta,D-galactopyranosyloxy]ethyl)-7-(1-carboxy-3-[4-aminophenyl]propyl)-4,10-bis(carboxymethyl)-1,4,7,10-tetraazacyclododecane (Gal-PA-DO3A-NH2) and 1-(2-[beta,D-galactopyranosyloxy]ethyl)-4,7,10-tris(carboxymethyl)-1, 4,7,10-tetraazacyclododecane (Gal-DO3A) chelating agents was developed involving full hydroxyl- and carboxyl-group protection in precursors to product. Two sequences of cyclen-N-functionalisation were subsequently investigated, one successfully, towards synthesis of the novel 'smart' bifunctional Gal-PA-DO3A-NH2 chelate. The longitudinal proton relaxivities of the neutral [Gd-(Gal-PA-DO3A-NH2)] and [Gd-(Gal-DO3A)] complexes were increased by 28% and 37% in the presence of beta-galactosidase, respectively.

The Precambrian sequences of the Avalon Zone in Canada (southeastern margin of the Appalachian Orogen) are interpreted as a Pan-African orogenic belt incorporated into the Appalachian Orogen during Palaeozoic times as its southeastern margin. The Precambrian evolution of the Avalon Zone was genetically unrelated to subsequent Palaeozoic evolution. The Avalon Zone shows marked similarities in age, tectonic history, and facies development to the Pan-African belts adjacent to the West African Craton. Precambrian evolution of the zone began with circa 800 Ma rifting of a sialic gneissic basement and deposition of a Middle Proterozoic(?) carbonate-clastic cover sequence. Early crustal rifting was associated with localized partial melting and metamorphism. Limited crustal separation led to the restricted development of circa 760 Ma oceanic volcanics. Continued rifting and subsequent closure of these narrow ocean basins led to the eruption of widespread subaerial volcanic suites, block faulting, granite plutonism, and local, late Proterozoic sedimentary basin formation. Precambrian evolution of the zone terminated with the Avalonian Orogeny (circa 650-600 Ma), a deformational event, the affects of which are most evident locally along the northwestern margin of the zone. The controlling features of the Proterozoic evolution of the Avalon Zone are a series of linear intracratonic troughs and small ocean basins that formed during thinning and separation of the crust by ductile spreading, rupture, and delamination (cf. Martin and Porada 1977). The variation in degree of crustal separation led to subsequent variation in orogenesis during late Proterozoic compression. The zone marks the original westward limit of Pan-African activity and displays no apparent genetic link with the Appalachian Orogen in Canada until Devonian times.

Objective: To assess developmental trends in physical activity and sedentary behaviour in British adolescents in relation to sex, ethnicity and socioeconomic status (SES).Design: A 5-year longitudinal study of a diverse cohort of students aged 11 - 12 years at baseline in 1999.Setting: 36 London schools sampled using a stratified random sampling procedure.Participants: A total of 5863 students categorised as white, black or Asian, and stratified for SES using the Townsend Index.Main outcome measures: Number of days per week of vigorous activity leading to sweating and breathing hard. Hours of sedentary behaviour, including watching television and playing video games. Data were analysed using multilevel, linear, mixed models.Results: Marked reductions in physical activity and increases in sedentary behaviour were noticed between ages 11 - 12 and 15 - 16 years. Boys were more active than girls, and the decline in physical activity was greater in girls (46% reduction) than in boys (23%). Asian students were less active than whites, and this was also true of black girls but not boys. Black students were more sedentary than white students. Levels of sedentary behaviour were greater in respondents from lower SES. Most differences between ethnic and SES groups were present at age 11 years, and did not evolve over the teenage years.Conclusions: Physical activity declines and sedentary behaviour becomes more common during adolescence. Ethnic and SES differences are observed in physical activity and sedentary behaviour in British youth that anticipate adult variations in adiposity and cardiovascular disease risk. These are largely established by age 11 - 12 years, so reversing these patterns requires earlier intervention.

Lung cancer screening has come a long way since the early studies with chest X-ray. Advancing technology and progress in the processing of images have enabled low dose CT to be tried and tested, and evidence suggests its use can result in a significant mortality benefit. There are several issues that need refining in order to successfully implement screening in the UK and elsewhere. Some countries have started patchy implementation of screening and there is increased recognition that the appropriate management of pulmonary nodules is crucial to optimise benefits of early detection, while reducing harm caused by inappropriate medical intervention. This review summarises and differentiates the many recent guidelines on pulmonary nodule management, discusses screening activity in other countries and exposes the present barriers to implementation in the UK.

Background The majority (>85%) of lung cancer cases are linked with smoking, and prognosis is poor because it is often diagnosed at a late stage. One contributor to late-stage diagnosis could be patient delay in help-seeking. We investigated the help-seeking behaviour of smokers and non-smokers for a recent lung cancer alarm symptom. Methods A health survey was sent to 4913 men and women aged >50 years through through General Practice. It included questions on symptoms experienced in the past 3 months (from a checklist), help-seeking (Yes/No) for each symptom and demographic characteristics including smoking status. Univariable and multivariable binary logistic regression analyses were used to assess the association between smoking status and help-seeking for a cough or hoarseness. Results Among 2042 participants (42% response rate), 280 (14%) reported ‘cough or hoarseness’ in the past 3 months; of whom 22% were current smokers. Being a smoker was associated with reduced likelihood of help-seeking (OR 0.44; 95% CI 0.23 to 0.83), even after adjusting for demographic factors (OR 0.46; 95% CI 0.21 to 1.00). Conclusions Delay in help-seeking in smokers for a symptom that is potentially indicative of lung cancer is a cause for concern. Future research could usefully address the psychological mechanisms through which help-seeking in smokers is hindered.

Preventive therapy is a risk reduction option for women who have an increased risk of breast cancer. The effectiveness of preventive therapy to reduce breast cancer incidence depends on adequate levels of uptake and adherence to therapy. We aimed to systematically review articles reporting uptake and adherence to therapeutic agents to prevent breast cancer among women at increased risk, and identify the psychological, clinical and demographic factors affecting these outcomes.Searches were carried out in PubMed, CINAHL, EMBASE and PsychInfo, yielding 3851 unique articles. Title, abstract and full text screening left 53 articles, and a further 4 studies were identified from reference lists, giving a total of 57. This review was prospectively registered with PROSPERO (CRD42014014957).Twenty-four articles reporting 26 studies of uptake in 21 423 women were included in a meta-analysis. The pooled uptake estimate was 16.3% [95% confidence interval (CI) 13.6-19.0], with high heterogeneity (I(2) = 98.9%, P0.001). Uptake was unaffected by study location or agent, but was significantly higher in trials [25.2% (95% CI 18.3-32.2)] than in non-trial settings [8.7% (95% CI 6.8-10.9)] (P0.001). Factors associated with higher uptake included having an abnormal biopsy, a physician recommendation, higher objective risk, fewer side-effect or trial concerns, and older age. Adherence (day-to-day use or persistence) over the first year was adequate. However, only one study reported a persistence of ≥ 80% by 5 years. Factors associated with lower adherence included allocation to tamoxifen (versus placebo or raloxifene), depression, smoking and older age. Risk of breast cancer was discussed in all qualitative studies.Uptake of therapeutic agents for the prevention of breast cancer is low, and long-term persistence is often insufficient for women to experience the full preventive effect. Uptake is higher in trials, suggesting further work should focus on implementing preventive therapy within routine care.

Background Deterioration in bone health is one of the presenting symptoms of Multiple Myeloma (MM), a cancer of plasma cells. As a consequence of this condition, patients suffer bone pain and bone damage and report cancer-related fatigue, resulting in deterioration in their quality of life. Evidence in patients with solid tumours shows promise for the positive effects of physical activity on quality of life. However, in the case of patients with MM a better understanding of the association between physical fitness and quality of life factors is still required. Therefore, this cohort study aims to objectively and longitudinally assess activity and fitness levels in patients with MM in order to explore their role in bone health, fatigue and quality of life for this patient population. Methods/Design The study is a prospective cohort study of MM patients in remission to assess physical activity, fatigue and bone health. Clinical markers of health, self-reported measures of psychological and physical well-being, and lifestyle behaviours are assessed at baseline, 3, 6 and 12 months. At each time point, patients complete cardiopulmonary exercise testing (CPET) along with a series of objective tests to assess physical fitness (eg accelerometry) and a number of self-report measures. A complementary qualitative study will be carried out in order to explore patients’ desire for lifestyle advice and when in their cancer journey they deem such advice to be useful. Discussion This study will be the first to prospectively and longitudinally explore associations between physical fitness and well-being, bone health, and fatigue (along with a number of other physical and clinical outcomes) in a cohort of patients with MM with the use of objective measures. The findings will also help to identify time points within the MM pathway at which physical activity interventions may be introduced for maximum benefit.

Objectives The present study tested the hypothesis that recall of receiving physical activity (PA) advice would be associated with higher levels of PA in patients with a diagnosis of colorectal cancer (CRC). Setting Colorectal cancer patients who were diagnosed in 2010 or 2011, and had been treated in the English National Health Service (NHS). Participants 17 753 respondents completed at least one section of the survey relevant to the current study and after exclusion of 171 with dementia (since results relied on recall), 15 254 had complete data for the current study. 60% were male, 67% were >65 years and 96% were from a white ethnic group. Primary and secondary outcome measures Patients completed the ‘Living with and Beyond Colorectal Cancer’ Patient-Reported Outcome Measures (PROMS) survey in 2013. The survey included questions on receiving exercise advice/information (‘PA advice’), and the frequency of currently doing at least 30 min of brisk PA per day (‘PA level’: 0, 1–4 or 5–7 days, within the past week; with the top category meeting UK guidelines). Results A third of respondents (31%) recalled receiving PA advice. Independent of demographics and treatment, patients who recalled having PA advice were more likely to be currently doing some brisk PA (51% in the advice group vs 42% in the no advice group; OR 1.74, 95% CI 1.60 to 1.90; p

Background: Women from Black, Asian and Minority Ethnic (BAME) backgrounds are less likely to attend cervical screening than White British women. This study explored sociodemographic and attitudinal correlates of cervical screening non-attendance among BAME women. Methods: Women (30–60 years) were recruited from Indian, Pakistani, Bangladeshi, Caribbean, African and White British backgrounds (n=720). Participants completed structured interviews. Results: BAME women were more likely to be non-attenders than white British women (44–71% vs 12%) and fell into two groups: the disengaged and the overdue. Migrating to the United Kingdom, speaking a language other than English and low education level were associated with being disengaged. Being overdue was associated with older age. Three attitudinal barriers were associated with being overdue for screening among BAME women: low perceived risk of cervical cancer due to sexual inactivity, belief that screening is unnecessary without symptoms and difficulty finding an appointment that fits in with other commitments. Conclusions: BAME non-attenders appear to fall into two groups, and interventions for these groups may need to be targeted and tailored accordingly. It is important to ensure that BAME women understand cancer screening is intended for asymptomatic women and those who have ceased sexual activity may still be at risk.

Objectives: To examine the proportion of normal-weight adolescents who consider themselves to be too heavy (size overestimation), and the proportion of overweight or obese adolescents who consider themselves to be about the right weight or too light (size underestimation), in large population-based samples collected over 8 years in England. Methods: Data were from the Health Survey for England between 2005 and 2012: an annual survey of households representative of the English population. We analysed data from 4979 adolescents (2668 boys, 2311 girls) aged 13 to 15 years old whose weight status was defined as normal weight or overweight/obese based on body mass index standard deviation scores (BMI-SDS) derived from objective measurements of height and weight and using International Obesity Task Force standards. Weight perception was based on the adolescent's choice from the following descriptors: ‘about the right weight', ‘too heavy' or ‘too light'. Results: The majority of normal-weight adolescents (83% of boys, 84% of girls) correctly identified themselves as ‘about the right weight'. Overestimation was uncommon, with only 7% of normal-weight teens (4% of boys, 11% of girls) identifying themselves as ‘too heavy'. In contrast, only 60% of overweight/obese adolescents (53% of boys, 68% of girls) correctly identified themselves as ‘too heavy', whereas 39% (47% of boys, 32% of girls) underestimated, identifying themselves as ‘about the right weight' or ‘too light'. There were no significant changes in BMI-SDS or body size estimation over time (2005–2012). Conclusions: Overestimation of body weight among normal-weight adolescents is relatively uncommon; potentially a cause for celebration. However, almost half of boys and a third of girls with a BMI placing them in the overweight or obese BMI range perceived themselves to be about the right weight. Lack of awareness of excess weight among overweight and obese adolescents could be a cause for concern.

One-third of preterm infants are diagnosed with bronchopulmonary dysplasia (BPD), a complex multifactorial disorder associated with significant morbidity. Associated pathologies include pulmonary hypertension (PH), a critical cardiorespiratory pathology with 48% 2-year mortality that affects up to a third of infants with BPD.1 Pulmonary vasodilatation in PH prolongs life, and phosphodiesterase-V inhibition is the primary approach for this.2 That stated, current evidence is limited to 45 patients across five case series.3 They demonstrate a reduction in overall mortality to 18%, but reservations remain regarding safety and efficacy. We therefore conducted a retrospective investigation into patients with BPD–PH managed at our centre between August 2008 and July …

Background: Attendance for cervical screening is socially graded, but little is known about patterns of attendance for colposcopy following an abnormal screening result. Methods: Logistic regression was used to regress colposcopy attendance status for 27 193 women against age and area-level deprivation, adjusting for ethnicity. Results: Colposcopy attendance was high at 8 weeks (89%) and 4 months post-referral (94%) but women living in the most deprived areas were significantly less likely to attend. Conclusions: The high overall attendance rates at colposcopy are encouraging but lower attendance among women in the most income-deprived areas indicates that even when these women attend primary cervical screening, they remain at higher risk of missing out on the benefits of the programme.

Purpose There is emerging evidence for the benefits of physical activity (PA) post-diagnosis for colorectal cancer (CRC) survivors. However, population studies suggest activity levels in these patients are very low. Understanding perceived barriers and benefits to activity is a crucial step in designing effective interventions. Methods Patients who were between 6 months and 5 years post-diagnosis with non-metastasised disease were identified from five London (UK) hospitals. Four hundred and ninety five completed a lifestyle survey that included open-ended questions on their perceived barriers (what things would stop you from doing more physical activity?) and benefits (what do you think you would gain from doing more physical activity?). Patients also recorded their activity levels using the Godin Leisure Time Exercise Questionnaire, along with sociodemographic and treatment variables. Results The most commonly reported barriers related to cancer and its treatments (e.g. fatigue). Age and mobility-related comorbidities (e.g. impaired mobility) were also frequently cited. Those who reported age and mobility as barriers, or reported any barrier, were significantly less active even after adjustment for multiple confounders. The most frequently reported benefits were physiological (e.g. improving health and fitness). Cancer-related benefits (such as prevention of recurrence) were rarely reported. Those perceiving physiological benefits or perceiving any benefits were more active in unadjusted models, but associations were not significant in adjusted models. Conclusions We have identified important barriers and facilitators in CRC survivors that will aid in the design of theory-based PA interventions.

DNA transposition reactions typically involve a strand transfer step wherein the transposon ends are covalently joined by the transposase protein to a short target site. There is very little known about the transposase-DNA interactions that direct this process, and thus our overall understanding of the dynamics of DNA transposition reactions is limited. Tn5 presents an attractive system for defining such interactions because it has been possible to solve the structure of at least one Tn5 transposition intermediate: a transpososome formed with pre-cleaved ends. However, insertion specificity in the Tn5 system is low and this has hampered progress in generating target-containing transpososomes that are homogeneous in structure (i.e. where a single target site is engaged) and therefore suitable for biochemical and structural analysis. We have developed a system where the Tn5 transpososome integrates almost exclusively into a single target site within a short DNA fragment. The key to establishing this high degree of insertion specificity was to use a target DNA with tandem repeats of a previously characterized Tn5 insertion hotspot. The target DNA requirements to form this strand transfer complex are evaluated. In addition, we show that target DNAs missing single phosphate groups at specific positions are better substrates for strand transfer complex formation relative to the corresponding unmodified DNA fragments. Moreover, utilization of missing phosphate substrates can increase the degree of target site selection. A method for concentrating and partially purifying the Tn5 strand transfer complex is described.

Literature publications (up to September 2004) concerning the targeted intervention of organophosphorus synthons in mechanisms of the replicative cycle, and the therapeutic benefits resulting (of particular relevance to anticancer and antiviral therapeutics) are reviewed. DNA-cross-linking agents comprising established oxazaphosphorinanes such as cyclophosphamide, ifosfamide and trofosfamide, and the aziridine agent thiotepa are discussed along with recent developments in prodrugs of associated activated metabolites. Established and novel nucleoside phosphonates are described subsequently in relation to inhibition of viral and cellular DNA polymerases and reverse transcriptases, along with inhibition of nucleotide metabolising enzymes such as purine nucleoside phosphorylase, thymidine phosphorylase, inosine monophosphate dehydrogenase, S-adenosyl-L-homocysteine hydrolase, and ribonucleoside diphosphate reductase. In this context, the role of organophosphorus chemistry in the development of intracellular delivery systems for antiviral/anticancer nucleotides has been reviewed, as have therapeutic developments concerning the pyrophosphate mimetic foscarnet. Finally, the inhibition of virally-encoded proteases such as HIV-PR, HCMV-PR and HCV NS3/NS4A protease by substrate-mimetic organophosphorus synthons has been discussed along with the role of synthetic oligonucleotides in antisense therapies for a range of disease-states.

The shells of marine and fresh water mollusks can serve as effective archives in retrieving information on natural and anthropogenic environmental changes. The advantage of using bivalves is that they integrate water chemistry changes into their shells during their life span. Retrospective study of environmental changes and pollutants using bivalve shells requires precise determination of the time of incorporation into the abiotic environmental matrix (here after age) of the specimen. For the first time, a set of archived bivalve samples (for which date of the death/collection is known) has been analyzed to establish the ages of mollusk shells using the 210 Pb– 226 Ra disequilibrium method. In addition, Sr and 90 Sr were analysed. The ages obtained using the 210 Pb/ 226 Ra disequilibrium dating method agrees well with the calendar years calculated from the date of death/collection. The ages obtained can be utilized to reconstruct the 90 Sr levels in the water column at sites where the mollusk shells were collected.

The histone-like nucleoid structuring (H-NS) protein is a global transcriptional regulator that is known to regulate stress response pathways and virulence genes in bacteria. It has also been implicated in the regulation of bacterial transposition systems, including Tn10. We demonstrate here that H-NS promotes Tn10 transposition by binding directly to the transposition complex (or transpososome). We present evidence that, upon binding, H-NS induces the unfolding of the Tn10 transpososome and helps to maintain the transpososome in an unfolded state. This ensures that intermolecular (as opposed to self-destructive intramolecular) transposition events are favored. We present evidence that H-NS binding to the flanking donor DNA of the transpososome is the initiating event in the unfolding process. We propose that by recruiting H-NS as a modulator of transposition, Tn10 has evolved a means of sensing changes in host physiology, as the amount of H-NS in the cell, as well its activity, are responsive to changes in environmental conditions. Sensing of environmental changes through H-NS would allow transposition to occur when it is most opportune for both the transposon and the host.

Transposition reactions take place in the context of higher-order protein-DNA complexes called transpososomes. In the Tn10 transpososome, IHF binding to an "outside end" creates a bend in the DNA that allows the transposase protein to contact the end at two different sites, the terminal and subterminal binding sites. Presumably this helps to stabilize the transposase-end interaction. However, the DNA loop that is formed must be unfolded at a later stage in order for the transposon to integrate into other DNA molecules. It has been proposed that transpososome unfolding also plays a role in transposon excision. To investigate this possibility further, we have isolated and characterized transposase mutants with altered transpososome unfolding properties. Two such mutants were identified, R182A and R184A. Both mutants fail to carry out hairpin formation, an intermediate step in transposon excision, specifically with outside end-containing substrates. These results support the idea that transpososome unfolding and excision are linked. Also, based on the importance of residues R182 and R184 in transpososome unfolding, we propose a new model for the Tn10 transpososome, wherein both DNA ends of the transpososome make subterminal contacts with transposase.

To compare differences in the management of the neonatal patent ductus arteriosus between neonatologists and paediatric cardiologists, physicians throughout the South-West were contacted. In treatment-refractory cases, neonatologists considered ligation less frequently than paediatric cardiologists (0% versus 40%; p

Summary The bacterial transposon Tn10 inserts preferentially into specific target sequences. This insertion specificity appears to be linked to the ability of target sites to adopt symmetrically positioned DNA bends after binding the transposition machinery. Target DNA bending is thought to permit the transposase protein to make additional contacts with the target DNA, thereby stabilizing the target complex so that the joining of transposon and target DNA sequences can occur efficiently. In the current work, we have asked whether the introduction of a discontinuity in a target DNA strand, a modification that is expected to make it easier for a DNA molecule to bend, can enhance or rescue target capture under otherwise suboptimal reaction conditions. We show that either a nick or a missing phosphate specifically at the site of reaction chemistry increases the ability of various target DNAs to form the target capture complex. The result suggests that the bends in the target DNA are highly localized and include the scissile phosphates. This raises the possibility that strand transfer is mechanistically linked to target capture. We have also identified specific residues in the target DNA and in transposase that appear to play an important role in target DNA bending.