Microstructural, microchemical, and mechanical changes associated with the clinical reuse of two nickel-titanium endodontic instruments.

BACKGROUND: Nickel-titanium (NiTi) instruments have represented a great technological development that enabled endodontists conforming irregular-shaped root canals. Notwithstanding, the repeated use of these instruments may lead to the fracture without any prior visible warning signs. This study aimed to evaluate how multiple clinical instrumentation/sterilization cycles of two NiTi mechanized instruments can affect their microstructural, microchemical, and mechanical characteristics. MATERIALS AND METHODS: In this observational descriptive study, a total of 140 NiTi instruments, 70 ProTaper Gold® (PTG) and 70 WaveOne Gold® (WOG) were analyzed. For each brand system, instruments were evaluated in the as-received condition (n = 10) and after one (n = 20), two (n = 20), and three (n = 20) instrumentation/sterilization cycles. Intraoperative instrumentation parameters were recorded for all used instruments. Afterward, the files were examined using scanning electron microscopy and energy-dispersive X-ray microanalysis. All of the instruments were tensile-fatigue tested until rupture in order to calculate the mechanical tensile strength and the maximum elongation percentage for the samples. Statistical analysis was completed using Chi-square, Kruskal-Wallis H-, or Mann-Whitney U-tests with a statistical significance set at P < 0.05. RESULTS: Significant increasing changes in surface topography (P < 0.05, Chi-square test) and chemical composition (P < 0.05, Kruskal-Wallis H-test) in both brand systems through instrumentation/sterilization cycles were detected. In addition, values of mechanical tensile strength and maximum elongation percentage increased significantly through instrumentation/sterilization cycles in the PTG group, whereas only the median values of mechanical tensile strength increased significantly in the WOG group (all P < 0.01, Kruskal-Wallis H-test). CONCLUSION: Although multiple instrumentation/sterilization cycles may render NiTi instruments more flexible and fatigue resistant, the significant changes detected in their surface topography and chemical composition should preclude their repeated clinical use in the routine endodontic practice as prevention for breakage.

COVID-19 y embarazo. Revisión y actualización / COVID-19 and pregnancy. Review and update / COVID-19 and pregnancy. Review and update

RESUMEN Objetivo . Buscar toda la información y evidencia disponible sobre el SARS-CoV-2 -que surgió en estos primeros 4 meses de 2020y el embarazo. Metodología . Revisión sistemática en las bases de datos PubMed y Google Scholar, hasta el 25 de abril de 2020. Se buscó artículos publicados relacionados con mujeres embarazadas infectadas con SARS-CoV-2. No hubo restricción de idioma. La búsqueda se extendió a las referencias de los artículos encontrados. Resultados . La enfermedad COVID-19 en mujeres embarazadas se caracteriza porque más del 90% de las pacientes evoluciona en forma leve, 2% requiere ingresar a las unidades de cuidados intensivos. Una muerte materna ha sido reportada. La prematuridad es alrededor de 25%, con predominio de recién nacidos prematuros tardíos; aproximadamente el 9% se complica con rotura prematura de membranas; la mortalidad perinatal es baja o similar a la de la población general y no se ha demostrado la transmisión vertical. Conclusiones . Los ginecólogos obstetras deben prepararse para atender cada vez más casos con COVID-19 y, por lo tanto, es necesario tener su conocimiento. La enfermedad evoluciona de la misma manera que en las no embarazadas, genera mayor prematuridad, no se ha demostrado la transmisión vertical, pero hay altas posibilidades de transmisión horizontal durante el parto vaginal.

ABSTRACT Objective : To search for all the information and available evidence on infection with SARS-CoV-2, a virus that appeared during the first 4 months of 2020, and pregnancy. Methods : Systematic review in PubMed and Google Scholar databases until April 25, 2020. We searched for published articles related to pregnant women infected with SARS-CoV-2. There was no language restriction. The search was extended to the references of the articles found. Results : In pregnant women with COVID-19, more than 90% of patients evolve mildly, 2% require intensive care. One maternal death has been reported. Prematurity occurs in approximately 25% of the cases, with predominance of late preterm infants; premature rupture of membranes presents in about 9%. Perinatal mortality is lower or similar to that of the general population, and vertical transmission has not been shown. Conclusions : Obstetrician-gynecologists must prepare to attend more cases with COVID-19 and therefore they need to know this disease. COVID-19 progresses similarly in pregnant and non-pregnant women, although it is associated to prematurity. While vertical transmission has not been demonstrated, horizontal transmission during vaginal birth is very likely.

AUC/MIC Pharmacodynamic Target Is Not a Good Predictor of Vancomycin Efficacy in Methicillin-Resistant Staphylococcus aureus Experimental Endocarditis.

The aim of this in vivo study was to compare the efficacy of vancomycin at standard doses (VAN-SD) to that of VAN at adjusted doses (VAN-AD) in achieving a VAN area under the curve/MIC ratio (AUC/MIC) of ≥400 against three methicillin-resistant Staphylococcus aureus (MRSA) strains with different microdilution VAN MICs in an experimental endocarditis model. The valve vegetation bacterial counts after 48 h of VAN therapy were compared, and no differences were observed between the two treatment groups for any of the three strains tested. Overall, for VAN-SD and VAN-AD, the rates of sterile vegetations were 15/45 (33.3%) and 21/49 (42.8%) (P = 0.343), while the medians (interquartile ranges [IQRs]) for log10 CFU/g of vegetation were 2 (0 to 6.9) and 2 (0 to 4.5) (P = 0.384), respectively. In conclusion, this VAN AUC/MIC pharmacodynamic target was not a good predictor of vancomycin efficacy in MRSA experimental endocarditis.

Cloning, expression, and characterisation of a Plasmodium vivax MSP7 family merozoite surface protein.

Plasmodium vivax remains the most widespread Plasmodium parasite species around the world, producing about 75 million malaria cases, mainly in South America and Asia. A vaccine against this disease is of urgent need, making the identification of new antigens involved in target cell invasion, and thus potential vaccine candidates, a priority. A protein belonging to the P. vivax merozoite surface protein 7 (PvMSP7) family was identified in this study. This protein (named PvMSP7(1)) has 311 amino acids displaying an N-terminal region sharing high identity with P. falciparum MSP7, as well as a similar proteolytical cleavage pattern. This protein's expression in P. vivax asexual blood stages was revealed by immuno-histochemical and molecular techniques.