Association between Paraoxonase-1 p.Q192R Polymorphism and Coronary Artery Disease susceptibility in the Colombian Population.

BACKGROUND: Paraoxonase-1 (PON1), a glycoprotein associated with serum high-density lipoprotein (HDL), has a central role in metabolizing lipid peroxides, exhibiting antiatherogenic properties. The polymorphism p.Q192R has been previously associated with coronary artery disease (CAD) susceptibility and clopidogrel response. PURPOSE: We aimed at investigating the association of PON1 p.Q192R with CAD and clopidogrel response in Colombian population. PATIENTS AND METHODS: The study was conducted among 163 patients diagnosed with CAD and treated with clopidogrel. The allele frequencies for the PON1 192Q and 192R alleles were determined in cases and Latin-American controls obtained from the public database gnomAD (n = 17,711). Response to clopidogrel was determined by assessing the platelet function using the INNOVANCE PFA-200 System. We determined the association between PON1 p.Q192R polymorphism, increased susceptibility to CAD and high on-treatment platelet reactivity (HPR) by using odds ratio (OR) and 95% confidence interval (CI) on four genetic models. RESULTS: The allele frequencies for the PON1 192Q and 192R alleles were 0.60 and 0.40, respectively. The allele distribution was found to be statistically different from the control group and other ethnic groups. The allele 192R was positively associated with decreased susceptibility to CAD under a dominant model (OR, 0.58; 95% CI, 0.42-0.8; P < 0.01). We found no association between the polymorphism and HPR. CONCLUSION: We propose that PON1 p.Q192R is a potentially useful marker for CAD susceptibility in the Colombian population and lacks association with HPR under clopidogrel treatment.

Influence of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid pH buffer on the biological response of marine algae.

The N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) is extensively used as pH buffer in culture media for testing chemicals. However, this study demonstrates that 0.01 M HEPES significantly reduces the rate of Cu, Pb, and Cd binding to Porphyra spp. and Enteromorpha spp. marine macroalgae. The HEPES also decreased the accumulation of Cu, Pb, and Cd but not Hg by these macroalgae. Both the extracellular adsorption and the intracellular uptake of the metals were influenced by HEPES to a similar extent. The HEPES also promoted the release of exudates by the algae, and these exudates form very stable complexes with Cu (and probably with other trace metal ions). The HEPES interference varied with the nature of the metal, the macroalga, and the season. The presence of 0.01 M HEPES in seawater cultures of the Emiliania huxleyi (a microalga) also interfered with E. huxleyi growth, liberation of Cu-complexing organic ligands, and Cu uptake. The HEPES, which displays surface activity, may facilitate the binding of metals to the algae for an initial exposure period. The metal taken up appears to stimulate the liberation of exudates that subsequently control the bioavailability of the metals and therefore metal uptake. Because HEPES can control the uptake of trace metals by algae and the production of organic ligands, the results obtained in cultures containing the HEPES pH buffer can be influenced by this component of the media.

Resistencia a la descementacion de brackets con fuerzas tangenciales / Shear bond strength resistance of brackets

El estudio fue de tipo comparativo y su diseño experimental. El propósito fue comparar los siguientes grados de resistencia a la descementación que presentan una resina de fotocurado de un paso (RADP), una resina de fotocurado de un paso (RFUP) y un polialqueonato de fotocurado modificado con resina (PFMR) sobre el esmalte dental, utilizando fuerzas tangenciales y así identificar cuál o cuales de estos agentes cementantes de brackets ofrecen mejores propiedades de adhesión al diente y al bracket. La muestra fue de 90 dientes premolares superiores e inferiores con extracción indicada por tratamiento ortodóntico, los cuales fueron asignados aleatoriamente a 3 grupos. Se cementaron los brackets con los tres materiales, siguiendo las recomendaciones de los fabricantes; luego de esto, los dientes se llevaron a un proceso de envejecimiento por medio de termociclado, se sometieron a fuerzas tangenciales con un dinamómetro tipo instron y se cuantificó en magapascales (Mpa) con cuánta fuerza se ocasionó la descementación de ese bracket. Para el análisis, se utilizó ANOVA para las pruebas física, y la prueba de Scheffe para comparar los adhesivos. Se presentaron diferencias sifnificativas, lo cual sugiere diferentes indicaciones de uso para el PFMR y la RFUP, con un promedio resistencia a la descementación de 20 Mpa.