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Christiane Auray-Blais Pamela Lavoie Shunji Tomatsu Vassili Valayannopoulos John J. Mitchell Julian Raiman Maxime Beaudoin Bruno Maranda Joe T.R. Clarke 《Analytica chimica acta》2016
Mucopolysaccharidoses (MPSs) are a group of disorders resulting from primary defects in lysosomal enzymes involved in the degradation of glycosaminoglycans (GAGs). Depending on the specific enzyme defect, the catabolism of one or more GAGs is blocked leading to accumulation in tissues and biological fluids. GAG measurements are important for high-risk screening, diagnosis, monitoring treatment efficacy, and patient follow up. The dimethylmethylene blue (DMB) spectrophotometric method commonly used in most biochemical genetics laboratories relies on a non-specific total GAG analysis which has led to false positive results, and even false negative results (mainly for MPS III and IV patients). The main objective of our project was to devise and validate a reliable tandem mass spectrometry multiplex analysis for the urine quantitation of four GAGs (dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS), and chondroitin sulfate (CS)) for an eventual technological transfer to the clinic. The developed methodology is rapid (7 min) and our results showed good intraday and interday precision (RSDs ≤ 8.7%) and accuracy (Biases range: −12.0%–18.4%). Linearity was good (r2 > 0.995) for DS, HS, CS, and KS calibration curves. In comparison with the DMB spectrophotometric method, this multiplex tandem mass spectrometry method allows GAG fractionation, thus a differentiation of MPS types, except for MPS I and II which are characterized by the same GAG profile. The devised method is a useful and reliable tool for diagnosis of MPS patients, as well as their monitoring and follow up, as shown by longitudinal studies. 相似文献
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Crowley JD Leigh DA Lusby PJ McBurney RT Perret-Aebi LE Petzold C Slawin AM Symes MD 《Journal of the American Chemical Society》2007,129(48):15085-15090
We report the design, synthesis, characterization, and operation of a [2]rotaxane in which a palladium-complexed macrocycle can be translocated between 4-dimethylaminopyridine and pyridine monodentate ligand sites via reversible protonation, the metal remaining coordinated to the macrocycle throughout. The substitution pattern of the ligands and the kinetic stability of the Pd-N bond means that changing the chemical state of the thread does not automatically cause a change in the macrocycle's position in the absence of an additional input (heat and/or coordinating solvent/anion). Accordingly, under ambient conditions any of the four sets of protonated and neutral, stable, and metastable co-conformers of the [2]rotaxane can be selected, manipulated, isolated, and characterized. 相似文献
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Wessig P Möllnitz K Eiserbeck C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(17):4859-4872
A modular approach for the synthesis of molecular rods based on oligospiroketals has been developed. The strategy relies on different terminal and intermediate segments, which are joined by ketal formation between ketones and diols. For this purpose it was necessary to develop a new ketalization method to circumvent some problems related with the established methods. The terminal segments are either derived from 4-piperidinone or from 4-oxocyclohexane carboxylic acid whereas the intermediate segments rest on pentaerythritol and cyclohexane-1,4-dione. A series of trispiro (14-18), hexaspiro (19) and nonaspiro (20) compounds have been prepared and characterized. From these we realized that it is imperative to use solubility enhancing groups if more than seven rings are joined. 相似文献
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Christiane S. Reiners 《Chemie in Unserer Zeit》2001,35(2):110-115
One of the main questions of science education is the selection of subjects, i.e.: Why do certain chemical subjects have to be taught? The answer implies the proving that the subject is scientifically relevant, has exemplifying features and is significant in every‐day‐life. The subject‐matter „Rare Earths”︁ does not seem to correspond to these criteria at first glance. The adjective „ rare”︁ evokes rather opposite associations. Perhaps rare earths are rare on earth and consequently of less scientific relevance? Perhaps they have rare properties and are therefore less exemplifying? Or they are even not relevant in our every‐day‐life? Definitely they are rare teaching subjects. At second glance the rare earth elements do correspond to the criteria and there are good reasons for including the topic in teacher education. 相似文献
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