Staphylococcus aureus is known worldwide as the principal cause of human bacterial infections; as well as methicillin-resistant Staphylococcus aureus (MRSA), is a major cause of hospital-acquired infections that are becoming increasingly difficult to combat because of emerging resistance to all current antibiotic classes. This work aims to carry out a theoretical study of molecules derived from beta-lactam compounds with possible potential antibiotic activity on Staphylococcus aureus. Therefore, computational chemistry tools were used to describe the interactions between potentially active molecules and the transpeptidase and beta-lactamase enzyme. These molecules were docked with transpeptidase and beta-lactamase enzymes, and all of them showed a higher affinity for transpeptidase (−1.81 kcal mol−1) than the reference molecule (methicillin), but only two showed a lower affinity for beta-lactamase (−6.8 kcal mol−1). The two ligands that presented the best ranking docking results were subjected to molecular dynamics simulations to assess conformational stability through root mean square deviation (RMSD) and root mean square fluctuation (RMSF) analysis. According to simulation, the ligands that bind to the proteins do not cause significant conformational changes in the structures of the proteins. The absorption, distribution, metabolism, and excretion (ADME) properties of the molecules with the lowest affinity for beta-lactamase were estimated. The ADME properties predict that the molecules would have good bioavailability. methicillinresistant methicillin resistant MRSA, MRSA , (MRSA) hospitalacquired hospital acquired classes betalactam beta lactam Therefore betalactamase lactamase enzyme enzymes −1.81 181 1 81 (−1.8 mol−1 mol1 mol methicillin, (methicillin) −6.8 68 6 8 (−6. mol−1. . RMSD (RMSD RMSF (RMSF analysis simulation absorption distribution metabolism (ADME estimated bioavailability (MRSA −1.8 18 (−1. mol− (methicillin −6. (−6 −1. (−1 −6 (− −1 − (

La metodología analítica para la cuantificación de warfarina sódica en tabletas de 5 mg fue estandarizada y validada mediante cromatografía líquida de alta eficiencia acoplada a detector de arreglo de diodo (HPLC-DAD). Se usó como fase móvil una mezcla compuesta por MeOH-AcOH-H2O (68:1:32), una columna cromatográfica C8e Phenomenex® de 150 x 4,6 mm y tamaño de partícula de 5 μm. Los resultados analíticos muestran que el método es preciso, exacto y selectivo para este fármaco. La curva de calibración se realizó en un intervalo del 80 al 120%, en una concentración nominal de 0,1mg/mL, demostrando ser lineal con un coeficiente de correlación a r²> 0,990; el porcentaje de recuperación fue de 98,1% ± 1,3, la precisión medida a través de la repetibilidad y la precisión intermedia fue adecuada (%RSD<2). En la prueba de disolución se encontró un porcentaje de 92,3% ± 3.0. Por lo tanto, la metodología desarrollada cumple con las especificaciones establecida por la USP 38/ NF33.

The analytic methodology for the quantification of sodium warfarin tablets of 5 mg was standardized and validated by High Efficiency Liquid Chromatography coupled to Diode Array Detector (HPLC-DAD). A mixture of MeOH-AcOH-H2O (68:1:32) was used like mobil phase, a chromatographic column C8e Phenomenex® of 150x4.6 mm and a particle size of 5 μm. The analytic results show that the method is precise, accurate and selective for this drug. The calibration curve was performed in the range of 80 to 120% at a nominal concentration of 0.1 mg/mL, demonstrating to be linear with a correlation coefficient at r²> 0.990; recovery rate was 98.1% ± 1.3 and the precision measured through repeatability and intermediate accuracy was adequate (% RSD <2). A percent of 92.3% ± 3.0 was found in dissolution test, thus, the methodology developed complies with the specifications established by USP 38/NF33.

Gingival overgrowth is an oral condition generated by the use of fixed orthodontic appliances. It was initially described as a product of the allergic response of the host to Nickel, and recent studies showed that this metal induces fibroblast proliferation. However, the degree of bioaccumulation of this metal in the oral cavity is unknown. The aim of this study was to quantify the concentrations of nickel in samples of saliva, dental plaque, and gingiva of individuals with fixed orthodontic appliances with and without gingival overgrowth. The sample size was established according to historical trends, evaluating 24 individuals with active orthodontic treatment, which were classified in two groups: 12 with gingival overgrowth (Group A) and 12 without gingival overgrowth (Group B). Samples of gingival, stimulated saliva and dental plaque were obtained from each participant. Once the sample were processed, nickel concentrations were measured in [mg/L] by atomic absorption spectrophotometry (Thermo Scientific. Atomic absorption spectrometer iCE 3000, UK). Statistical analysis was performed using SPSS v20. The levels of Nickel in samples of stimulated saliva, dental plaque and gingiva were compared between individuals in group A and group B. There were significantly higher levels of nickel in gingiva samples in group A (mean = 0.61 mg/L vs. 0.36 mg/L, P = .001). However, no statistical difference was observed when comparing the concentrations of nickel in saliva between groups A and B (mean = 0.502 mg/L vs. 0.473 mg/L, P = .178, respectively). The use of fixed orthodontic appliances leads to different levels of bioaccumulation of nickel in gingiva when comparing both groups. High concentrations of this metal are probably associated with the origin of gingival overgrowth. Further studies are required to establish causation.

El agrandamiento gingival es una de las alteraciones orales generadas por el uso de aparatología ortodóncica fija. Inicialmente fue descrito como producto de la respuesta alérgica del huésped al níquel, y estudios recientes demostraron que este metal induce proliferación fibroblástica. Sin embargo, se desconoce el grado de bioacumulación de este metal en la cavidad oral. El objetivo del presente estudio consistió en cuantificar la concentración de níquel en muestras de saliva, placa dental y encía de individuos con aparatología ortodóncica fija con y sin agrandamiento gingival. El tamaño de la muestra se estableció según tendencia histórica, evaluando un total de 24 individuos con tratamiento ortodóncico activo, los cuales fueron clasificados en 2 grupos: 12 con agrandamiento gingival (grupo A) y 12 sin agrandamiento gingival (grupo B). De cada participante se obtuvieron muestras de: encía, saliva estimulada y placa dental. Una vez procesadas las muestras se midieron las concentraciones de níquel en mg/l, mediante espectrofotometría de absorción atómica (Thermo Scientific. Atomic absorption spectrometer iCE 3000, Reino Unido). El análisis estadístico se realizó mediante el software SPSS v20. Al comparar los niveles de níquel en muestras de saliva estimulada, placa dental y encía entre los individuos con y sin agrandamiento gingival, se observaron niveles significativamente mayores de níquel en las muestras de encía del grupo A (medias = 0,61 mg/l vs 0,36 mg/l; p = 0,001). Sin embargo, no se observó diferencia estadísticamente significativa al comparar las concentraciones de Ni en saliva entre el grupo A y B (medias = 0,502 mg/l vs 0,473 mg/l; p = 0,178, respectivamente). A partir de estos resultados se concluye que el uso de aparatología ortodóncica fija conlleva distintos niveles de bioacumulación de iones níquel en la encía al comparar ambos grupos. Es probable que altas concentraciones de este metal estén relacionadas con la etiología del agrandamiento gingival, por lo que se requieren nuevos estudios para establecer causalidad.