Release of oxidizing fluids in subduction zones recorded by iron isotope zonation in garnet

Subduction zones are key regions of chemical and mass transfer between the Earth’s surface and mantle. During subduction, oxidized material is carried into the mantle and large amounts of water are released due to the breakdown of hydrous minerals such as lawsonite. Dehydration accompanied by the release of oxidizing species may play a key role in controlling redox changes in the subducting slab and overlying mantle wedge. Here we present measurements of oxygen fugacity, using garnet–epidote oxybarometry, together with analyses of the stable iron isotope composition of zoned garnets from Sifnos, Greece. We find that the garnet interiors grew under relatively oxidized conditions whereas garnet rims record more reduced conditions. Garnet δ56Fe increases from core to rim as the system becomes more reduced. Thermodynamic analysis shows that this change from relatively oxidized to more reduced conditions occurred during lawsonite dehydration. We conclude that the garnets maintain a record of progressive dehydration and that the residual mineral assemblages within the slab became more reduced during progressive subduction-zone dehydration. This is consistent with the hypothesis that lawsonite dehydration accompanied by the release of oxidizing species, such as sulfate, plays an important and measurable role in the global redox budget and contributes to sub-arc mantle oxidation in subduction zones

Erythropoietin in amyotrophic lateral sclerosis: a multicentre, randomised, double blind, placebo controlled, phase III study

OBJECTIVE: To assess the efficacy of recombinant human erythropoietin (rhEPO) in amyotrophic lateral sclerosis (ALS). METHODS: Patients with probable laboratory-supported, probable or definite ALS were enrolled by 25 Italian centres and randomly assigned (1:1) to receive intravenous rhEPO 40,000 IU or placebo fortnightly as add-on treatment to riluzole 100 mg daily for 12 months. The primary composite outcome was survival, tracheotomy or >23 h non-invasive ventilation (NIV). Secondary outcomes were ALSFRS-R, slow vital capacity (sVC) and quality of life (ALSAQ-40) decline. Tolerability was evaluated analysing adverse events (AEs) causing withdrawal. The randomisation sequence was computer-generated by blocks, stratified by centre, disease severity (ALSFRS-R cut-off score of 33) and onset (spinal or bulbar). The main outcome analysis was performed in all randomised patients and by intention-to-treat for the entire population and patients stratified by severity and onset. The study is registered, EudraCT 2009-016066-91. RESULTS: We randomly assigned 208 patients, of whom 5 (1 rhEPO and 4 placebo) withdrew consent and 3 (placebo) became ineligible (retinal thrombosis, respiratory insufficiency, SOD1 mutation) before receiving treatment; 103 receiving rhEPO and 97 placebo were eligible for analysis. At 12 months, the annualised rate of death (rhEPO 0.11, 95% CI 0.06 to 0.20; placebo: 0.08, CI 0.04 to 0.17), tracheotomy or >23 h NIV (rhEPO 0.16, CI 0.10 to 0.27; placebo 0.18, CI 0.11 to 0.30) did not differ between groups, also after stratification by onset and ALSFRS-R at baseline. Withdrawal due to AE was 16.5% in rhEPO and 8.3% in placebo. No differences were found for secondary outcomes. CONCLUSIONS: RhEPO 40,000 IU fortnightly did not change the course of ALS

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Processamento mínimo de beterraba.

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Effect of Domperidone on QTc Interval in Term and Preterm Newborns: Is It Really Unsafe?

BACKGROUND: Domperidone is a prokinetic drug widely used in newborns for motility disorders. Sporadic cases of QTc prolongation and ventricular tachyarrhythmia related to intravenous domperidone have been reported. Small studies with variable methodology have reported conflicting effects of oral domperidone on QTc in newborns. OBJECTIVE: To evaluate the effect of domperidone on QTc interval in term and preterm newborns. DESIGN/METHODS: A retrospective analysis of QTc changes in newborns treated with domperidone was performed. Only patients for whom at least 2 ECG recordings were available, one taken while on therapy and one while off therapy, were included. QT interval was measured on lead II according to standard methods and corrected for heart rate by the formula of Bazett. Staistically univariate analysis were performed using paired t-test. Subgroup analysis was performed for preterm and term newborns. RESULTS: Data for 80 patients (mean GA 32wks, BW 1735g) were collected and 91 ECG pairs were available (52 before starting therapy and while on treatment, 39 on treatment and after discontinuation). Domperidone was administered in the mean oral dose of 1.6 mg/kg*d (range 0.8-2.4) at a median postnatal age of 29 days. During therapy mean QTc was 0.394\ub10.034msec. The dosage of domperidone did not affect absolute QTc values neither QTc variations. In 3 pts QTc exceeded the upper normal limits of 440ms. No episodes of ventricular arrhythmia or life-threatening events were observed. No significant changes in QTc were detected before starting and while on treatment (p=0,52); a slight decrease in QTc was observed after domperidone discontinuation (p=0,03). In the subgroup analysis this effect was only seen in preterm (GA< 36wks, p=0,02) and not in term infants (p=0,7). CONCLUSIONS: Oral domperidone administered in the recommended dose range seems to be safe in preterm and term newborns. In preterm infants minor changes in QTc intervals may be detected but they do not seem to be clinically significant