Browsing by Author "Diaz, V."
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- ItemCervical Artery Dissections with and without stroke, risk factors and prognosis : a Chilean prospective cohort(2020) Mazzon, E.; Rocha, D.; Brunser, A. M.; De la Barra, C.; Stecher, X.; Bernstein, T.; Zuniga, P.; Diaz, V.; Martínez, Gonzalo; Venturelli, P. M.
- ItemDiagnóstico de los trastornos respiratorios del sueño en recién nacidos con sospecha de apneas: comparación entre la saturometría nocturna y la poligrafía(2017) Zenteno, D.; Bancalari, A.; Navarro, X.; Diaz, V.; Rodriguez-Nunez, I.; Brockmann Veloso, Pablo EdmundoIntroduction: Night Continuous Saturometry (CSO2) is used in Neonatal Units to detect events of hypoxemia in Newborns (NB) with apnea episodes. Polygraphy (PG) has a larger number of measu- ring channels. Our goal was to evaluate the diagnostic performance of CSO2 compared to Polygra- phy in NB with suspected sleep apneas. Patients and Method: Results of CSO2 and PG performed simultaneously in RN with suspected apneas were retrospectively analyzed over a three-year period. A 2-channel Masimo Radical-7® pulse oximeter and an Apnea Link Plus® polygraph with 5 simulta- neous recording channels were used. Altered PG was defined as: desaturation index under 80% per hour ≥ 1 and/or number of desaturations under 80% ≥ 20 seconds greater than one in the whole va- lidated registry and/or hypoapnea apnea index ≥ 1 event per hour. In parallel, altered SpO2C was de- fined when one or both of the 80% saturation criteria were altered. Sensitivity, specificity, predictive values and Likelihood Ratio (LLR) for CSO2 were calculated. Results were expressed in absolute value, with 95% confidence interval. Results: Simultaneous 40 CSO2 and PG were performed; 80% (32/40) of them were preterm infants, 60% (24/40) males. 38% (15/40) of the CSO2 and 15% (6/40) of the PGs were altered (p < 0.05). CSO2 has a 100% Sensitivity, 74% Specificity, 40% VPP, 100% VPN, LLR + 3.78 and LLR-0. Conclusion: In the studied NB, CSO2 has a high diagnostic value, however, it may present false positives; It is suggested to use as a screening method and to perform diagnostic confirmation with another sleep test, such as PG.
- ItemSpectroscopic Properties and Biocompatibility Studies of CdTe Quantum Dots Capped with Biological Thiols(AMER SCIENTIFIC PUBLISHERS, 2012) Diaz, V.; Ramirez Maureira, M.; Monras, J. P.; Vargas, J.; Bravo, D.; Osorio Roman, I. O.; Vasquez, C. C.; Perez Donoso, J. M.CdTe quantum dots (QDs) capped with two relevant biological thiols, glutathione (GSH) or cysteine (Cys) were synthesized in aqueous solution using CdCl2, K2TeO3 and NaBH4 and their chemical, spectroscopic and biocompatibility properties were assessed. Synthesized nanoparticles (NPs) are 3-6 nm in diameter, with emission spectra between 480-580 nm depending on QDs size, and emission quantum yields between 0.35-0.65. The toxicity of thiol-capped CdTe NPs to different bacterial strains was determined. Increased biocompatibility for Cys-capped QDs was observed. In addition, QDs uptake by eukaryotic cells was evaluated by fluorescence microscopy. CdTe-GSH NPs were incorporated into MKN45 cells only in the presence of lipofectamine. On the other hand, although CdTe-Cys NPs were freely incorporated into these cells, the amount of incorporation as well as the number of fluorescent cells was lower than that observed with GSH-capped QDs. Finally, no significant changes in cell morphology as a consequence of GSH- or Cys-capped QDs incorporation were observed. Summarizing, our results indicate that the as-synthesized GSH- and Cys-capped QDs display differential spectroscopic properties and cellular interactions, being CdTe-Cys more biocompatible than CdTe-GSH NPs.