1.
Comparison of Cardioprotective Effects of Propofol versus Sevoflurane in Pediatric Living Donor Liver Transplantation.
Weng, Y, Yuan, S, Li, H, Yu, W
Annals of transplantation. 2020;:e923398
Abstract
BACKGROUND Our study compared the myocardiac protective effect of propofol vs. sevoflurane in pediatric patients receiving living donor liver transplantation (LDLT) surgery. MATERIAL AND METHODS We randomly and equally divided 120 children who underwent LDLT into a sevoflurane group and a propofol group. Preoperative, intraoperative, and postoperative data were collected and compared between the 2 groups. The concentrations of cTnI, CK-MB, IL-6, TNF-alpha, and HMGB1 at 5 min after induction (T0), 30 min in the anhepatic period (T1), and 3 h after reperfusion (T2), and at the end of surgery (T3) were measured. RESULTS There was no statistically significant difference in the characteristics of children in the 2 groups. Compared with T0, the levels of IL-6 and TNF-alpha at T1, T2, and T3 were higher, while the HMGB1 at T2 and T3 were higher (P<0.05). A similar trend for IL-6, TNF-alpha, and HMGB1 at different time points in the 2 groups was observed. Compared with T0, the cTnI and CK-MB at T2 and T3 were significantly higher (P<0.05), but there was no significant difference at different time points in the 2 groups. For the adverse events, there was no significant difference between the 2 groups. CONCLUSIONS Our study shows that the cardioprotective effect in pediatric patients undergoing living donor liver transplantation is similar with propofol and sevoflurane anesthesia.
2.
Virtual screening of mandelate racemase mutants with enhanced activity based on binding energy in the transition state.
Gu, J, Liu, M, Guo, F, Xie, W, Lu, W, Ye, L, Chen, Z, Yuan, S, Yu, H
Enzyme and microbial technology. 2014;:121-7
Abstract
Mandelate racemase (MR) is a promising candidate for the dynamic kinetic resolution of racemates. However, the poor activity of MR towards most of its non-natural substrates limits its widespread application. In this work, a virtual screening method based on the binding energy in the transition state was established to assist in the screening of MR mutants with enhanced catalytic efficiency. Using R-3-chloromandelic acid as a model substrate, a total of 53 mutants were constructed based on rational design in the two rounds of screening. The number of mutants for experimental validation was brought down to 17 by the virtual screening method, among which 14 variants turned out to possess improved catalytic efficiency. The variant V26I/Y54V showed 5.2-fold higher catalytic efficiency (k(cat)/K(m)) towards R-3-chloromandelic acid than that observed for the wild-type enzyme. Using this strategy, mutants were successfully obtained for two other substrates, R-mandelamide and R-2-naphthylglycolate (V26I and V29L, respectively), both with a 2-fold improvement in catalytic efficiency. These results demonstrated that this method could effectively predict the trend of mutational effects on catalysis. Analysis from the energetic and structural assays indicated that the enhanced interactions between the active sites and the substrate in the transition state led to improved catalytic efficiency. It was concluded that this virtual screening method based on the binding energy in the transition state was beneficial in enzyme rational redesign and helped to better understand the catalytic properties of the enzyme.