Risk assessment for aortic dissection in Turner syndrome: The role of the aortic growth rate.

OBJECTIVE: The risk of aortic dissection (AoD) is increased in Turner syndrome (TS) but predicting those at risk is difficult. Based on scarce evidence, preventive aortic surgery is recommended when aortic diameter increases >5 mm/year. To investigate the aortic growth rate in TS and TS-related conditions associated with aortic growth. We also reported our experience of women who suffered aortic dissection (AoD), and who had preventive aortic replacement. METHODS: 151 adult TS were retrospectively identified. Women who had more than one transthoracic echocardiogram (TTE) after age 16 years were included in the aortic growth study. Aortic diameters at sinuses of Valsalva (SoV) and ascending aorta (AA) were analysed by two experts. RESULTS: 70/151 women had more than one TTE (interscan interval 4.7 years). Mean aortic growth was 0.13 ± 0.59 mm/year at SoV and 0.23 ± 0.82 mm/year at AA. Known risk factors for aortic dilatation and TS-related conditions were not associated with aortic growth. 4/151 women experienced AoD (age 25±8 years): two had paired scans for aortic growth, which was 0.67 mm/year at both SoV and AA in the first woman, and 11 mm/year (SoV) and 4 mm/year (AA) in the second. Only 1/4 of women with AoD survived; she used a TS cardiac-alert card to inform emergency personnel about her risk of AoD. 5/151 had a preventive aortic replacement, but one died post-operatively. CONCLUSIONS: Mean aortic growth in our TS population was increased compared to non-TS women and was not associated with currently known risk factors for AoD, suggesting that aortic growth rate itself could be a useful variable to stratify who is at risk for AoD.

Measurement of myocardial native T1 in cardiovascular diseases and norm in 1291 subjects.

BACKGROUND: Native T1-mapping provides quantitative myocardial tissue characterization for cardiovascular diseases (CVD), without the need for gadolinium. However, its translation into clinical practice is hindered by differences between techniques and the lack of established reference values. We provide typical myocardial T1-ranges for 18 commonly encountered CVDs using a single T1-mapping technique - Shortened Look-Locker Inversion Recovery (ShMOLLI), also used in the large UK Biobank and Hypertrophic Cardiomyopathy Registry study. METHODS: We analyzed 1291 subjects who underwent CMR (1.5-Tesla, MAGNETOM-Avanto, Siemens Healthcare, Erlangen, Germany) between 2009 and 2016, who had a single CVD diagnosis, with mid-ventricular T1-map assessment. A region of interest (ROI) was placed on native T1-maps in the "most-affected myocardium", characterized by the presence of late gadolinium enhancement (LGE), or regional wall motion abnormalities (RWMA) on cines. Another ROI was placed in the "reference myocardium" as far as possible from LGE/RWMA, and in the septum if no focal abnormality was present. To further define normality, we included native T1 of healthy subjects from an existing dataset after sub-endocardial pixel-erosions. RESULTS: Native T1 of patients with normal CMR (938 ± 21 ms) was similar compared to healthy subjects (941 ± 23 ms). Across all patient groups (57 ± 19 yrs., 65% males), focally affected myocardium had significantly different T1 value compared to reference myocardium (all p < 0.001). In the affected myocardium, cardiac amyloidosis (1119 ± 61 ms) had the highest native T1 compared to normal and all other CVDs, while iron-overload (795 ± 58 ms) and Anderson-Fabry disease (863 ± 23 ms) had the lowest native reference T1 (all p < 0.001). Future studies designed to detect the large T1 differences between affected and reference myocardium are estimated to require small sample-sizes (n < 50). However, studies designed to detect the small T1 differences between reference myocardium in CVDs and healthy controls can require several thousand of subjects. CONCLUSIONS: We provide typical T1-ranges for common clinical cardiac conditions in the largest cohort to-date, using ShMOLLI T1-mapping at 1.5 T. Sample-size calculations from this study may be useful for the design of future studies and trials that use T1-mapping as an endpoint.

AAA-DDD triple hydrogen bond complexes.

Experiment and theory both suggest that the AAA-DDD pattern of hydrogen bond acceptors (A) and donors (D) is the arrangement of three contiguous hydrogen bonding centers that results in the strongest association between two species. Murray and Zimmerman prepared the first example of such a system (complex 3*2) and determined the lower limit of its association constant (K(a)) in CDCl(3) to be 10(5) M(-1) by (1)H NMR spectroscopy (Murray, T. J. and Zimmerman, S. C. J. Am. Chem. Soc. 1992, 114, 4010-4011). The first cationic AAA-DDD pair (3*4(+)) was described by Bell and Anslyn (Bell, D. A. and Anslyn, E. A. Tetrahedron 1995, 51, 7161-7172), with a K(a) > 5 x 10(5) M(-1) in CH(2)Cl(2) as determined by UV-vis spectroscopy. We were recently able to quantify the strength of a neutral AAA-DDD arrangement using a more chemically stable AAA-DDD system, 6*2, which has an association constant of 2 x 10(7) M(-1) in CH(2)Cl(2) (Djurdjevic, S., Leigh, D. A., McNab, H., Parsons, S., Teobaldi, G. and Zerbetto, F. J. Am. Chem. Soc. 2007, 129, 476-477). Here we report on further AA(A) and DDD partners, together with the first precise measurement of the association constant of a cationic AAA-DDD species. Complex 6*10(+)[B(3,5-(CF(3))(2)C(6)H(3))(4)(-)] has a K(a) = 3 x 10(10) M(-1) at RT in CH(2)Cl(2), by far the most strongly bound triple hydrogen bonded system measured to date. The X-ray crystal structure of 6*10(+) with a BPh(4)(-) counteranion shows a planar array of three short (NH...N distances 1.95-2.15 A), parallel (but staggered rather than strictly linear; N-H...N angles 165.4-168.8 degrees), primary hydrogen bonds. These are apparently reinforced, as theory predicts, by close electrostatic interactions (NH-*-N distances 2.78-3.29 A) between each proton and the acceptor atoms of the adjacent primary hydrogen bonds.

Safer pharmacy practice: a preliminary study of significant event analysis and peer feedback.

OBJECTIVES: The aim was to investigate the effectiveness of significant event analyses (SEAs) undertaken by pharmacists as judged by a new system of independent peer feedback. METHOD: The setting was a convenience sample of 37 pharmacists working in community pharmacy, secondary care and academic settings in NHS Scotland. Preliminary study involved the content analysis of pharmacists' SEAs and written feedback reports, which were generated by pharmacists trained in using a validated instrument to facilitate peer feedback. The content of reports and feedback letters were systematically coded and categorised by identifying and quantifying key words and phrases. Data collected included the range and severity of significant events identified; the reported reasons for the events occurring; types of learning needs identified; action(s) taken; and learning issues raised by peer feedback. KEY FINDINGS: A total of 37 pharmacists submitted 43 SEA reports during the study period. All events submitted were classified as having a negative impact on the quality and safety of patient care. Most events related to prescribing, dispensing, administration, communication and patient-/relative-centred issues. Patients reportedly came to harm in 13% of cases. Sixty-three per cent of reported learning needs related to personal awareness/responsibilities when undertaking work tasks, and 58% of implemented change involved amending existing protocols or introducing new procedures. Seventy per cent of SEAs were judged to be 'satisfactory' by the peer reviewers. The effectiveness of change implementation and providing a clear description of an event were highlighted as key issues which required improvement in those event analyses judged to be 'unsatisfactory'. CONCLUSIONS: The findings demonstrate that most pharmacists in this study were able to apply SEA in a satisfactory manner by demonstrating reflective learning, undertaking insightful analyses and implementing necessary change. SEA and peer feedback may have a potential role to play in enhancing the quality and safety of pharmacy practices.

SAM (dependent) I AM: the S-adenosylmethionine-dependent methyltransferase fold.

The S-adenosylmethionine-dependent methyltransferase enzymes share little sequence identity, but incorporate a highly conserved structural fold. Surprisingly, residues that bind the common cofactor are poorly conserved, although the binding site is localised to the same region of the fold. The substrate-binding region of the fold varies enormously. Over the past two years, there has been a significant increase in the number of structures that are known to incorporate this fold, including several uncharacterized proteins and two proteins that lack methyltransferase activity.

Australia experiments with 'experimental use' exemption.

Lawmakers are asking whether Australian researchers need an express 'experimental use' defense against patent infringement.

Molecular recognition of sub-micromolar inhibitors by the epinephrine-synthesizing enzyme phenylethanolamine N-methyltransferase.

The crystal structures of human phenylethanolamine N-methyltransferase in complex with S-adenosyl-l-homocysteine (7, AdoHcy) and either 7-iodo-1,2,3,4-tetrahydroisoquinoline (2) or 8,9-dichloro-2,3,4,5-tetrahydro-1H-2-benzazepine (3, LY134046) were determined and compared with the structure of the enzyme complex with 7 and 7-aminosulfonyl-1,2,3,4-tetrahydroisoquinoline (1, SK&F 29661). The enzyme is able to accommodate a variety of chemically disparate functional groups on the aromatic ring of the inhibitors through adaptation of the binding pocket for this substituent and by subtle adjustments of the orientation of the inhibitors within the relatively planar binding site. In addition, the interactions formed by the amine nitrogen of all three inhibitors reinforce the hypothesis that this functional group mimics the beta-hydroxyl of norepinephrine rather than the amine. These studies provide further clues for the development of improved inhibitors for use as pharmacological probes.