ABSTRACT
The current standard of care for patients with chronic hepatitis C virus (HCV) infection is a combination of direct-acting antiviral agents (DAAs). Most HCV patients treated with these drugs achieve viral elimination, but 1% to 15% fail to attain this objective. Treatment failures are usually related to relapse, and less often to on-treatment viral breakthrough. HCV drug resistant associated substitutions are detected in most patients who do not eliminate the virus. The risk of developing these variants depends on host- and virus-related factors, the properties of the drugs used, and the treatment strategies applied. Patients who carry Resistant Associated Substitutions (RASs) may not obtain benefits from treatment, and are at a risk of disease progression. Whether HCV RASs persist depends on their type: NS3-4A variants often disappear gradually after DAA therapy is stopped, whereas NS5A variants tend to persist for more than 2 years. The best way to prevent emergence of resistant variants is to eliminate the virus at the first treatment using highly potent DAAs with genetic barriers to resistance. For those who fail an NS5A inhibitor, deferral of treatment is recommended pending the availability of additional data if they do not have cirrhosis or reasons for urgent re-treatment. If re-treatment is needed, the most commonly used strategy is sofosbuvir as backbone therapy plus a drug from a class other than that previously used, for 24 weeks. Unless it is contraindicated, weight-based ribavirin should also be added. If available, nucleotide-based (eg, sofosbuvir) triple or quadruple DAA regimens may be considered. The optimal treatment for patients who fail an NS5A inhibitor and those with multidrug-resistant variants remains to be defined, and research efforts should continue to focus on treatment for these patients.
Subject(s)
Humans , Antiviral Agents/therapeutic use , Drug Resistance, Viral , Drug Therapy, Combination , Genotype , Hepacivirus/genetics , Hepatitis C, Chronic/drug therapy , Recurrence , Ribavirin/therapeutic use , Sofosbuvir/therapeutic useABSTRACT
En este estudio se evaluó, in vitro, la capacidad de acumulación de mercurio (Hg) que pueda poseer la caña flecha (Gynerium sagittatum) (Aubl) Beauv. como una alternativa viable de ser implementada para la rehabilitación de suelos contaminados. Este estudio fue realizado en el laboratorio de Biotecnología Vegetal de la Universidad de Sucre (9º18 N, 75º23 O). Se usó un diseño experimental de bloques al azar, un análisis de varianza para comparación de medias, una prueba de Tukey (p≤0,05) para la establecer las diferencias significativas entre los tratamientos, pruebas de normalidad (Kolmogorov-Smirnov) y test de homogeneidad de varianza de Bartlett. Los análisis de mercurio se realizaron en un espectrofotómetro de absorción atómica Thermo Electron S4, provisto de una celda con ventanas de cuarzo, por el método de espectroscopia de absorción atómica con vapor frío. Los resultados muestran que la parte de la planta que presenta mayor acumulación es la raíz con 55,98 µg g-1 HgT, seguida de los tallos-hojas con 14,84 µg g-1 HgT, valores relacionados con el grado de concentración del metal en el medio de cultivo. Además, la acumulación de mercurio en raíces y tallos aumentó con el tiempo. En conclusión, in vitro esta planta acumula Hg debido a las altas concentraciones en sus tejidos sin afectar la viabilidad de las plantas.
In this in vitro study was evaluated the potential for accumulation of mercury (Hg) that can hold the cane arrow (Gynerium sagittatum) (Aubl) Beauv. as a viable alternative to be implemented for the rehabilitation of contaminated soils. This study was conducted at the Plant Biotechnology Laboratory, University of Sucre (9º 18' N, 75° 23' W). An experimental design was randomized block, an analysis of variance to compare means, Tukey test (p ≤ 0.05) to establish significant differences between the treatments, tests of normality (Kolmogorov-Smirnov) and homogeneity test Bartlett variance. The mercury analyses were performed on atomic absorption spectrophotometer Thermo Electron S4, a cell equipped with quartz windows, by the method of atomic absorption spectrometry with cold steam. The results show that the plant part that presents the greatest accumulation is the root with 55.98 mg g-1 HgT, followed by the stems, leaves 14.84 g g-1 HgT and these values are related to the degree of metal concentration in the culture medium. Furthermore, the accumulation of mercury in roots and stems increased with time. In conclusion, in vitro this plant accumulates due to the high Hg concentrations in their tissues without affecting the viability of plants.