Hydrogen abstraction from H-donor substrates by the 6-CF3-benzotriazol-N-oxyl radical (TFNO)

The aminoxyl radical 6-trifluoromethyl-benzotriazol-N-oxyl (TFNO) has been generated from the parent hydroxylamine 6-CF3-1-hydroxy-benzotriazole (TFBT) by one-electron oxidation with a Ce-IV salt and characterized by spectrophotometry and cyclic voltammetry (CV). Rate constants of H-abstraction (k(H)) by TFNO from a number of H-donor benzylic substrates have been determined spectrophotometrically in MeCN solution at 25 degrees C. A radical H-atom transfer (HAT) route of oxidation is substantiated for TFNO by several pieces of evidence. The kinetic data also testify the relevance of stereoelectronic effects upon the HAT reactivity of TFNO. Copyright (C) 2010 John Wiley & Sons, Ltd

Translation of the Amsterdam Preoperative Anxiety and Information Score (APAIS) into the Amharic Version and Its Validation for Evaluation of Preoperative Anxiety

BACKGROUND፡ Peri-operative anxiety is a vague, unpleasant feeling, the source of which is often nonspecific and unknown to the individual. It affects all aspects of anesthesia. Although the magnitude and consequences of preoperative anxiety are well documented in the developed world, there are limited studies conducted in Ethiopia. The primary aim of this study is to produce the Amharic version of APAIS and evaluate its validity in assessing the prevalence of preoperative anxiety in surgical patients.METHODS: A cross-cultural adaptation process using a forward/backward translation of the APAIS scale was performed. The Amharic version was then tested in 365 sampled elective adult surgical patients scheduled for surgery at Tikur Anbessa specialized Hospital. The validity of the translated version was also checked by evaluating its psychometric properties of internal validity and acceptability.Result: The results showed that the reliability of the APAISAmharic was high (Cronbach's alpha of 0.87) and the data collected was a good fit (RMSEA of 0.04). In addition, the questionnaire was well-accepted 100% with no missing values for each dimension of the APAIS. The mean APAIS scores for total anxiety and desire for information were 11.6 and 6.0 respectively and 58.9% of the study participants had anxiety and those patients, who had some form of formal education, came from urban areas, had previous anesthesia experience and complications and who had average or high information requirement was more likely to be anxious.CONCLUSION: APAIS-Amharic is a reliable and acceptable tool for measuring patients’ preoperative anxiety and their need for information. It can be used routinely as a screening instrument at pre-anesthesia clinics to assess patients’ level of anxiety

An assessment of the relative contributions of redox and steric issues to laccase specificity towards putative substrates

Laccases catalyze the one-electron oxidation of a broad range of substrates coupled to the 4 electron reduction of O-2 to H2O. Phenols are typical substrates, because their redox potentials (ranging from 0.5 to 1.0 V vs. NHE) are low enough to allow electron abstraction by the T1 Cu(II) that, although a relatively modest oxidant (in the 0.4-0.8 V range), is the electron-acceptor in laccases. The present study comparatively investigated the oxidation performances of Trametes villosa and Myceliophthora thermophila laccases, two enzymes markedly differing in redox potential (0.79 and 0.46 V). The oxidation efficiency and kinetic constants of laccase-catalyzed conversion of putative substrates were determined. Hammett plots related to the oxidation of substituted phenols by the two laccases, in combination with the kinetic isotope effect determination, confirmed a rate-determining electron transfer from the substrate to the enzyme. The efficiency of oxidation was found to increase with the decrease in redox potential of the substrates, and the Marcus reorganisation energy for electron transfer to the T1 copper site was determined. Steric hindrance to substrate docking was inferred because some of the phenols and anilines investigated, despite possessing a redox potential compatible with one-electron abstraction, were scarcely oxidised. A threshold value of steric hindrance of the substrate, allowed for fitting into the active site of T. villosa laccase, was extrapolated from structural information provided by X-ray analysis of T. versicolor lac3B, sharing an identity of 99% at the protein level, thus enabling us to assess the relative contribution of steric and redox properties of a substrate in determining its susceptibility to laccase oxidation. The inferred structural threshold is compatible with the distance between two phenylalanine residues that mark the entrance to the active site. Interaction of the substrate with other residues of the active site is commented on

Building regional anesthesia capacity in limited-resource settings: a pilot study evaluating a 4-week curriculum

Aim: To pilot a 4-week regional anesthesia curriculum for limited-resource settings. Intervention: A baseline needs assessment and knowledge test were deployed. The curriculum included lectures and hands-on teaching, followed by knowledge attainment tests. Results: Scores on the knowledge test improved from a mean of 37.1% (SD 14.7%) to 50.9% (SD 18.6%) (p = 0.017) at 4 weeks and 49% at 24 months. An average of 1.7 extremity blocks per month was performed in 3 months prior to the curriculum, compared with an average of 4.1 per month in 8 months following. Conclusion: This collaborative curriculum appeared to have a positive impact on the knowledge and utilization of regional anesthesia. Keywords: capacity building; curriculum; education; global health; post-graduate medical education; regional anesthesiology; residency training; resource-limited settin