Patient safety and estimation of renal function in patients prescribed new oral anticoagulants for stroke prevention in atrial fibrillation

OBJECTIVE: In clinical trials of dabigatran and rivaroxaban for stroke prevention in atrial fibrillation (AF), drug eligibility and dosing were determined using the Cockcroft-Gault equation to estimate creatine clearance as a measure of renal function. This cross-sectional study aimed to compare whether using estimated glomerular filtration rate (eGFR) by the widely available and widely used Modified Diet in Renal Disease (MDRD) equation would alter prescribing or dosing of the renally excreted new oral anticoagulants. PARTICIPANTS: Of 4712 patients with known AF within a general practitioner-registered population of 930 079 in east London, data were available enabling renal function to be calculated by both Cockcroft-Gault and MDRD methods in 4120 (87.4%). RESULTS: Of 4120 patients, 2706 were <80 years and 1414 were ≥80 years of age. Among those ≥80 years, 14.9% were ineligible for dabigatran according to Cockcroft-Gault equation but would have been judged eligible applying MDRD method. For those <80 years, 0.8% would have been incorrectly judged eligible for dabigatran and 5.3% would have received too high a dose. For rivaroxaban, 0.3% would have been incorrectly judged eligible for treatment and 13.5% would have received too high a dose. CONCLUSIONS: Were the MDRD-derived eGFR to be used instead of Cockcroft-Gault in prescribing these new agents, many elderly patients with AF would either incorrectly become eligible for them or would receive too high a dose. Safety has not been established using the MDRD equation, a concern since the risk of major bleeding would be increased in patients with unsuspected renal impairment. Given the potentially widespread use of these agents, particularly in primary care, regulatory authorities and drug companies should alert UK doctors of the need to use the Cockcroft-Gault formula to calculate eligibility for and dosing of the new oral anticoagulants in elderly patients with AF and not rely on the MDRD-derived eGFR

High-resolution Observations of OH(1720 MHz) Masers Toward the Galactic Center

High-resolution VLA observations of 1720 MHz OH maser emission from Sgr A East and the circumnuclear disk with spatial and spectral resolutions of $\approx$ 2\dasec5 $\times$ 1\dasec3 and 0.27 \kms are reported. This follow-up observational study focuses on the recent discovery of a number of such OH maser features and their intense circularly polarized maser lines detected toward these Galactic center sources. The 1720 MHz maser line of OH arises from collisionally excited gas behind a C-type shock and is an important diagnostic of the interaction process that may occur between molecular clouds and associated X-ray emitting shell-type supernova remnants. The present observations have confirmed that the observed Stokes $V$ signal is due to Zeeman splitting and that the OH masers are angularly broadened by the scattering medium toward the Galactic center. The scale length of the magnetic field fluctuations in the scattering medium toward the Galactic center is estimated to be greater than 0.1-0.2 pc using the correlation of the position angles of the scatter-broadened maser spots. In addition, the kinematics of the maser spots associated with Sgr A East are used to place a 5 pc displacement between this extended radio structure and the Galactic center.Comment: 13 pages, 2 Tables and 2 figures, to be published in Ap

Carboxylic-acid-passivated metal oxide nanocrystals : ligand exchange characteristics of a new binding motif

Ligand exchange is central in the processing of inorganic nanocrystals (NCs) and requires understanding of surface chemistry. Studying sterically stabilized HfO2 and ZrO2 NCs using H-1 solution NMR and IR spectroscopy as well as elemental analysis, this paper demonstrates the reversible exchange of initial oleic acid ligands for octylamine and self-adsorption of oleic acid at NC surfaces. Both processes are incompatible with an X-type binding motif of carboxylic acids as reported for sulfide and selenide NCs. We argue that this behavior stems from the dissociative adsorption of carboxylic acids at the oxide surface. Both proton and carboxylate moieties must be regarded as X-type ligands yielding a combined X-2 binding motif that allows for self-adsorption and exchange for L-type ligands

Dyspraxia in clinical education: a review

Background The stereotype of the student with dyspraxia as ‘clumsy and disorganised’ may cause clinical teachers to be concerned about the student’s performance in a clinical environment. However, if it is understood that dyspraxic students possess many strengths, as well as weaknesses, it may be that some stereotypical myths may be dispelled and more effective support offered to them. This review considers the research surrounding the experiences of students and health professionals with dyspraxia within higher education (HE), alongside the personal experiences of EW, in order to inform the development of clinical teachers in respect of their support for learners with dyspraxia. Findings A literature review produced five relevant articles. Four studies focussed on HE students and one on doctors. A significant theme was that dyspraxia impaired learning new skills. Doctors with dyspraxia tended not to disclose their condition, due to fear of stigmatisation and negative effects on their career. Positive attributes of dyspraxia included resilience and determination to succeed. Two main adaptations to dyspraxia were highlighted; a ‘difference’ view focussing on individuals’ strengths, and a ‘medical/deficit’ view, focussing on their weaknesses and others’ negative perceptions. Discussions and Recommendations It is important for clinical educators to understand and support students with dyspraxia – as clinical environments can be particularly difficult for them. Dyspraxia has both positive and negative effects. Here we discuss the findings of previous studies in the context of EWAA’s personal experiences. We also present a series of practical recommendations, whilst recognising that more research is required to document their impact in clinical education

Undergraduate teaching on biological weapons and bioterrorism at medical schools in the UK and the Republic of Ireland: results of a cross-sectional study

Objective To determine if individual undergraduate schools of medicine in the UK and the Republic of Ireland provide any teaching to medical students about biological weapons, bioterrorism, chemical weapons and weaponised radiation, if they perceive them to be relevant issues and if they figure them in their future plans. Design A cross-sectional study utilising an internet-based questionnaire sent to key figures responsible for leading on the planning and delivery of undergraduate medical teaching at all schools of medicine in the UK and Ireland. Setting All identified undergraduate schools of medicine in the UK and Ireland between August 2012 and December 2012. Outcome measures Numerical data and free text feedback about relevant aspects of undergraduate teaching. Results Of the 38 medical schools approached, 34 (28 in UK, 6 in Ireland) completed the questionnaire (89.47%). 4 (all in UK) chose not to complete it. 6/34 (17.65%) included some specific teaching on biological weapons and bioterrorism. 7/34 (20.59%) had staff with bioterrorism expertise (mainly in microbiological and syndromic aspects). 4/34 (11.76%) had plans to introduce some specific teaching on bioterrorism. Free text responses revealed that some felt that because key bodies (eg, UK's General Medical Council) did not request teaching on bioterrorism, then it should not be included, while others regarded this field of study as a postgraduate subject and not appropriate for undergraduates, or argued that the curriculum was too congested already. 4/34 (11.76%) included some specific teaching on chemical weapons, and 3/34 (8.82%) on weaponised radiation. Conclusions This study provides evidence that at the present time there is little teaching at the undergraduate level in the UK and Ireland on the subjects of biological weapons and bioterrorism, chemical weapons and weaponised radiation and signals that this situation is unlikely to change unless there were to be high-level policy guidance

A new method for imaging nuclear threats using cosmic ray muons

Muon tomography is a technique that uses cosmic ray muons to generate three dimensional images of volumes using information contained in the Coulomb scattering of the muons. Advantages of this technique are the ability of cosmic rays to penetrate significant overburden and the absence of any additional dose delivered to subjects under study above the natural cosmic ray flux. Disadvantages include the relatively long exposure times and poor position resolution and complex algorithms needed for reconstruction. Here we demonstrate a new method for obtaining improved position resolution and statistical precision for objects with spherical symmetry