Browsing by Author "Faundez, M."
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- ItemFactors Associated With Accidental Decannulation in Tracheostomized Children(2023) Villarroel Silva, Gregory; Oyarzun, I.J.; Baranao Garces, Patricio; Mendez Raggi, Mireya Patricia; Faundez, M.; Jalil Contreras, Yorschua Frederick; Fernandez, T.R.; Munoz, S.R.BACKGROUND: Tracheostomy has many benefits for pediatric patients in the ICU, but it is also associated with complications. Accidental decannulation (AD) is a frequent complication and cause of mortality in this population. Our study aimed to determine the factors associated with AD in tracheostomized pediatric subjects. METHODS: This was a case-control study with 1:2 allocation ratio. Participants were tracheostomized children hospitalized in a prolonged mechanical ventilation hospital between 2013–2018. Each child who experienced decannulation during the study period was included as a case at the time of the event. Controls were obtained from the same population and were defined as subjects without an AD event during the same period. RESULTS: One hundred forty patients were hospitalized at Josefina Martinez Hospital at the time, of whom 41 were selected as cases and 82 as controls. Median (interquartile range) age was 20 (12–36) months, being 60% male. The median time from tracheostomy placement to AD event was 364 (167–731) d. Eighty-four percent of subjects were mechanically ventilated. AD mainly occurred by self-decannulation (53.7%). The risk of AD was higher in children who reached the midline in a sitting position (odds ratio 9.5 [95% CI 1.59-53.90]), inner di-ameter (ID) tracheostomy tube size ? 4.0 mm (odds ratio 5.18 [95% CI 1.41-19.06]), and who had been hospitalized in hospital rooms with a low ratio of nursing staff for each subject (1 nurse to 4 subjects) (odds ratio 4.48 [95% CI 1.19-16.80]). CONCLUSIONS: Factors associated with a higher risk of AD in tracheostomized children included the ability to reach the midline in a sitting position, the use of a smaller tracheostomy tube (? 4.0 mm ID), and lower supervision from staff.
- ItemMechanisms underlying the inhibition of the cytochrome P450 system by copper ions(WILEY, 2009) Letelier, M. E.; Faundez, M.; Jara Sandoval, J.; Molina Berrios, A.; Cortes Troncoso, J.; Aracena Parks, R.; Marin Catalan, R.Copper toxicity has been associated to the capacity of free copper ions to catalyze the production of superoxide anion and hydroxyl radical, reactive species that modify the structure and/or function of biomolecules. In addition, nonspecific Cu2+-binding to thiol enzymes, which modifies their catalytic activities, has been reported. Cytochrome P450 (CYP450) monooxygenase is a thiol protein that binds substrates in the first and limiting step of CYP450 system catalytic cycle, necessary for the metabolism of lipophilic xenobiotics. Therefore, copper ions have the potential to oxidize and bind to cysteinyl residues of this monooxygenase, altering the CYP450 system activity. To test this postulate, we studied the effect of Cu2+ alone and Cu2+/ascorbate in rat liver microsomes, to independently evaluate its nonspecific binding and its pro-oxidant effects, respectively. We assessed these effects on the absorbance spectrum of the monooxygenase, as a measure of structural damage, and p-nitroanisole O-demethylating activity of CYP450 system, as a marker of functional impairment. Data obtained indicate that Cu2+ could both oxidize and bind to some amino acid residues of the CYP450 monooxygenase but not to its heme group. The differences observed between the effects of Cu2+ and Cu2+/ascorbate show that both mechanisms are involved in the catalytic activity inhibition of CYP450 system by copper ions. The significance of these findings on the pharmacokinetics and pharmacodynamics of drugs is discussed. Copyright (C) 2009 John Wiley & Sons, Ltd.
- ItemMercury(II) extraction using a poly(3,4-ethylenedioxythiophene) modified electrode(2011) Arteaga, G.C.; del Valle, M.A.; Antilen Lizana, Monica Paulina; Faundez, M.; Gacitúa, M.A.; Díaz, F.R.; Bernède, J.C.; Cattin, L.
- ItemNitrofuran drugs beyond redox cycling: Evidence of Nitroreduction-independent cytotoxicity mechanism(2020) Gallardo-Garrido, C.; Cho, Y.; Cortes-Rios, J.; Vasquez, D.; Pessoa-Mahana, C. D.; Araya-Maturana, R.; Pessoa-Mahana, H.; Faundez, M.Nitrofurans (5-nitro-2-hydrazonylfuran as pharmacophore) are a group of widely used antimicrobial drugs but also associated to a variety of side effects. The molecular mechanisms that underlie the cytotoxic effects of nitrofuran drugs are not yet clearly understood. One-electron reduction of 5-nitro group by host enzymes and ROS production via redox cycling have been attributed as mechanisms of cell toxicity. However, the current evidence suggests that nitrofuran ROS generation by itself is uncapable to explain the whole toxic effects associated to nitrofuran consumption, proposing a nitro-reduction independent mechanism of toxicity.
- ItemPromising 2,6,9-trisubstituted purine derivatives for anticancer compounds: Synthesis, 3D-QSAR, and preliminary biological assays(2020) Salas, C.O.; Zarate, A.M.; Kryštof, V.; Mella, J.; Faundez, M.; Brea, J.; Loza, M.I.; Brito, I.; Hendrychová, D.; Jorda, R.; Cabrera Caballero, Alan Raul; Tapia, R.A.; Espinosa-Bustos, C.
- ItemUse of fluorine-doped tin oxide electrodes for lipoic acid determination in dietary supplements(2012) Miranda, M. P.; del Rio, R.; del Valle, M. A.; Faundez, M.; Armijo, F.This paper reports a novel application of fluorine-doped tin oxide electrodes (FTO). To this purpose, electrochemical oxidation mechanism of lipoic acid (LA) at different pHs in the presence of interferents was investigated. FTO displayed electroactivity toward LA oxidation at pH 2. The results indicated that interference from water soluble interferents, derived from excipients or other components coming from dietary supplements, is completely removed with the use of FTO. Square-wave voltammetry, SWV, studies have been shown that at pH 2 an anodic peak at about 0.95 V vs. Ag/AgCl, KCl(sat'd) appears. It was also demonstrated that LA oxidation is diffusion-controlled, involving two electrons in the overall process. From these results, a FTO-based electrode was proposed as LA sensor. SWV was the technique of choice for LA quantitation. A linear range between 5 and 500 mu mol L-1 was found. These results allowed postulating FTO as a potential candidate for the electrochemical determination of LA in the presence of interferents contained in pharmaceutical samples of supplementary diet. (C) 2012 Elsevier B.V. All rights reserved.