Role of therapeutic approach in the treatment outcome, hospital costs, one-year post-hospital medical costs and quality of life in the patients who survived acute methanol poisoning.

(v češtině) Kontext: Akutní otrava metanolem je závažný klinický stav vyžadující okamžitou léčbu. V České republice probíhala masivní vlna otrav metanolem v letech 2012-2013. Náklady na léčbu pacientů s akutní otravou metanolem představují významnou finanční zátěž pro zdravotnický systém. Dopad zvoleného léčebného postupu na náklady zdravotnického systému s ohledem na klinickou účinnost, tedy výsledek léčby, není zcela znám, stejně jako jeho dopad na kvalitu života pacientů přeživších otravu. Cíl: Porovnání jednotlivých terapeutických postupů, aplikace různých druhů antidot (fomepizol versus etanol) a mimotělních eliminačních metod (intermitentní versus kontinuální hemodialýza), pro optimalizaci léčby akutní otravy metanolem z hlediska "cost-effectiveness", tedy nákladové efektivity, klinických výsledků léčby, nákladů na hospitalizaci a následnou posthospitalizační péči, a kvality života pacientů přeživších otravu. Metodika: Do prospektivní kohortové studie byli zařazeni všichni pacienti hospitalizování v letech 2012-2013 s akutní otravou metanolem (n=106). Do studie nákladů na hospitalizační péči a nákladů v průběhu roku po propuštění z nemocnic byli zařazeni všichni pacienti přeživší akutní otravu (n=83). Do longitudinální studie kvality života pomocí dotazníku SF-36 byli zařazeni pacienti...(English) Background: Methanol poisoning is severe medical condition with a need of urgent intensive treatment. Mass poisoning outbreak took place in the Czech Republic in 2012-2013. Costs of hospital treatment of methanol poisoning present significant financial burden to healthcare systems. The effect of treatment modality choice on clinical outcome and healthcare costs is not known, as well as its impact on the quality of life of methanol poisoning survivors after hospital discharge. Aim: To compare different therapeutic methods, choice of antidote (fomepizole versus ethanol) and extracorporeal elimination method (intermittent vs. continuous dialysis) for optimizing clinical outcome, cost-effectiveness, hospital costs, post-discharge costs, and the quality of life in survivors. Methods: For prospective cohort study, all patients hospitalized with acute methanol poisoning were included (n=106); for hospital and one-year healthcare costs study, all survivors of acute methanol poisoning (n=83) were included. For longitudinal quality of life study all survivors with informed consent (n=54) and control group of chronic alcohol abusers, age- and gender-balanced, without history of methanol poisoning (n=23), were included. Results: Comparative data of clinical effectiveness of elimination techniques...Department of Occupational Medicine First Faculty of Medicine and General University HospitalKlinika pracovního lékařství 1. LF UK a VFN1. lékařská fakultaFirst Faculty of Medicin

Cyclic Octapeptides Composed of Two Glutathione Units Outperform the Monomer in Lead Detoxification

A rationally-designed scaffold of cyclic octapeptides composed of two units of the natural tripeptide glutathione (GSH) was optimized to strongly and selectively capture toxic lead ions (Pb(II)). Using state-of-the-art computational tools, a list of eleven plausible peptides was shortened to five analogs based on their calculated affinity to Pb(II) ions. We then synthesized and investigated them for their abilities to recover Pb-poisoned human cells. A clear pattern was observed from the in vitro detoxification results, indicating the importance of cavity size and polar moieties to enhance metal capturing. These, together with the apparent benefit of cyclizing the peptides, improved the detoxification of the two lead peptides by approximately two folds compared to GSH and the benchmark chelating agents against Pb poisoning. Moreover, the two peptides did not show any toxicity and, therefore, were thoroughly investigated to determine their potential as next-generation remedies for Pb poisoning

Proton Affinities of Organocatalysts Derived from Pyridine N-oxide

Proton affinities of several efficient organocatalysts METHOX, QUINOX, ANETOX, KOTOX, FUREOX, and FUROOX bearing a pyridine N-oxide or 2,2′-bipyridyl N,N′-dioxide moiety were de-termined by using extended kinetic method and density functional theory calculations. Proton affinities are in the range of 1030–1060 kJ mol–1. Using isodesmic reactions, the effect of combining two pyridine N-oxide units in the neutral and the protonated molecule was studied: The combination of an unfavorable interaction in the former case and a favorable interaction in the latter accounts for the superbasic proper¬ties of 2,2′-bipyridyl N,N′-dioxides. Last but not least, the theoretically predicted pKa in ethanol are 0.1, –2.7, 0.9, 1.8, 1.9, and 2.3 for the METHOX, QUINOX, ANETOX, FUROOX, FUREOX, and KOTOX, respectively

Catalytic Cycle of Multicopper Oxidases Studied by Combined Quantum- and Molecular-Mechanical Free-Energy Perturbation Methods

We have used combined quantum mechanical and molecular mechanical free-energy perturbation methods in combination with explicit solvent simulations to study the reaction mechanism of the multicopper oxidases, in particular the regeneration of the reduced state from the native intermediate. For 52 putative states of the trinuclear copper cluster, differing in the oxidation states of the copper ions and the protonation states of water- and O2-derived ligands, we have studied redox potentials, acidity constants, isomerisation reactions, as well as water- and O2 binding reactions. Thereby, we can propose a full reaction mechanism of the multicopper oxidases with atomic detail. We also show that the two copper sites in the protein communicate so that redox potentials and acidity constants of one site are affected by up to 0.2 V or 3 pKa units by a change in the oxidation state of the other site

Reorganization Energy for Internal Electron Transfer in Multicopper Oxidases.

We have calculated the reorganization energy for the intramolecular electron transfer between the reduced type 1 copper site and the peroxy intermediate of the trinuclear cluster in the multicopper oxidase CueO. The calculations are performed at the combined quantum mechanics and molecular mechanics (QM/MM) level, based on molecular dynamics simulations with tailored potentials for the two copper sites. We obtain a reorganization energy of 91-133 kJ/mol, depending on the theoretical treatment. The two Cu sites contribute by 12 and 22 kJ/mol to this energy, whereas the solvent contribution is 34 kJ/mol. The rest comes from the protein, involving small contributions from many residues. We have also estimated the energy difference between the two electron-transfer states and show that the reduction of the peroxy intermediate is exergonic by 43-87 kJ/mol, depending on the theoretical method. Both the solvent and the protein contribute to this energy difference, especially charged residues close to the two Cu sites. We compare these estimates with energies obtained from QM/MM optimizations and QM calculations in a vacuum and discuss differences between the results obtained at various levels of theory

Stability mechanisms of a thermophilic laccase probed by molecular dynamics.

Laccases are highly stable, industrially important enzymes capable of oxidizing a large range of substrates. Causes for their stability are, as for other proteins, poorly understood. In this work, multiple-seed molecular dynamics (MD) was applied to a Trametes versicolor laccase in response to variable ionic strengths, temperatures, and glycosylation status. Near-physiological conditions provided excellent agreement with the crystal structure (average RMSD ∼0.92 Å) and residual agreement with experimental B-factors. The persistence of backbone hydrogen bonds was identified as a key descriptor of structural response to environment, whereas solvent-accessibility, radius of gyration, and fluctuations were only locally relevant. Backbone hydrogen bonds decreased systematically with temperature in all simulations (∼9 per 50 K), probing structural changes associated with enthalpy-entropy compensation. Approaching T opt (∼350 K) from 300 K, this change correlated with a beginning "unzipping" of critical β-sheets. 0 M ionic strength triggered partial denucleation of the C-terminal (known experimentally to be sensitive) at 400 K, suggesting a general salt stabilization effect. In contrast, F(-) (but not Cl(-)) specifically impaired secondary structure by formation of strong hydrogen bonds with backbone NH, providing a mechanism for experimentally observed small anion destabilization, potentially remedied by site-directed mutagenesis at critical intrusion sites. N-glycosylation was found to support structural integrity by increasing persistent backbone hydrogen bonds by ∼4 across simulations, mainly via prevention of F(-) intrusion. Hydrogen-bond loss in distinct loop regions and ends of critical β-sheets suggest potential strategies for laboratory optimization of these industrially important enzymes