129 research outputs found

    Steviamine, a new class of indolizidine alkaloid [(1R,2S,3R,5R,8aR)-3-hydroxy­meth­yl-5-methyl­octa­hydro­indolizine-1,2-diol hydro­bromide]

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    X-ray crystallographic analysis of the title hydro­bromide salt, C10H20N+·Br−, of (1R,2S,3R,5R,8aR)-3-hydroxy­meth­yl-5-methyl­octa­hydro­indolizine-1,2-diol defines the absolute and relative stereochemistry at the five chiral centres in steviamine, a new class of polyhydroxy­lated indolizidine alkaloid isolated from Stevia rebaudiana (Asteraceae) leaves. In the crystal structure, mol­ecules are linked by inter­molecular O—H⋯Br and N—H⋯Br hydrogen bonds, forming double chains around the twofold screw axes along the b-axis direction. Intra­molecular O—H⋯O inter­actions occur

    2,6-Dide­oxy-2,6-imino-l-glycero-d-ido-heptitol

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    The title mol­ecule, C7H15NO5, the major product from selective enzymatic oxidation followed by hydrogeno­lysis of the corresponding azido­heptitol, was found by X-ray crystallography to exisit in a chair conformation with three axial hydroxyl groups. One of the hydroxymethyl groups is disordered over two sets of sites in a 0.590 (3):0.410 (3) ratio. In the crystal, O—H⋯O, O—H⋯(O,O), O—H⋯N and N—H⋯O hydrogen bonding occurs

    3,7,7a-Tri-epi-casuarine penta­acetate

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    The relative stereochemistry at six contiguous centres in an analogue of the natural product casuarine, viz. 3,7,7a-tri-epi-casuarine pentaacetate, C18H25NO10, has been established by an analysis of a crystalline pentaacetate. © 2006 International Union of Crystallography All rights reserved

    Surgical Treatment for Recurrent Bulbar Urethral Stricture: A Randomised Open-label Superiority Trial of Open Urethroplasty Versus Endoscopic Urethrotomy (the OPEN Trial)

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    BackgroundUrethral stricture affects 0.9% of men. Initial treatment is urethrotomy. Approximately, half of the strictures recur within 4 yr. Options for further treatment are repeat urethrotomy or open urethroplasty.ObjectiveTo compare the effectiveness and cost-effectiveness of urethrotomy with open urethroplasty in adult men with recurrent bulbar urethral stricture.Design, setting, and participantsThis was an open label, two-arm, patient-randomised controlled trial. UK National Health Service hospitals were recruited and 222 men were randomised to receive urethroplasty or urethrotomy.InterventionUrethrotomy is a minimally invasive technique whereby the narrowed area is progressively widened by cutting the scar tissue with a steel blade mounted on a urethroscope. Urethroplasty is a more invasive surgery to reconstruct the narrowed area.Outcome measurements and statistical analysisThe primary outcome was the profile over 24 mo of a patient-reported outcome measure, the voiding symptom score. The main clinical outcome was time until reintervention.Results and limitationsThe primary analysis included 69 (63%) and 90 (81%) of those allocated to urethroplasty and urethrotomy, respectively. The mean difference between the urethroplasty and urethrotomy groups was –0.36 (95% confidence interval [CI] –1.74 to 1.02). Fifteen men allocated to urethroplasty needed a reintervention compared with 29 allocated to urethrotomy (hazard ratio [95% CI] 0.52 [0.31–0.89]).ConclusionsIn men with recurrent bulbar urethral stricture, both urethroplasty and urethrotomy improved voiding symptoms. The benefit lasted longer for urethroplasty.Patient summaryThere was uncertainty about the best treatment for men with recurrent bulbar urethral stricture. We randomised men to receive one of the following two treatment options: urethrotomy and urethroplasty. At the end of the study, both treatments resulted in similar and better symptom scores. However, the urethroplasty group had fewer reinterventions

    Filtration–UV irradiation as an option for mitigating the risk of microbiologically influenced corrosion of subsea construction alloys in seawater

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    The effect of filtration-UV irradiation of seawater on the biofilm activity on several offshore structural alloys was evaluated in a continuous flow system over 90 days. Biofilms ennobled the electrode potential by +400–500 mV within a few days of exposure to raw untreated seawater. Filtration-UV irradiation of the seawater delayed the ennoblement of the steels for up to 40 days and lowered localized corrosion rates in susceptible alloys. Ennobling biofilms were composed of microbial cells, diatoms and extracellular polymeric substances and the bacterial community in biofilms was affected by both the alloy composition and seawater treatment

    Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

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    Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∌38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

    The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

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    Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care
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