ABSTRACT
Objective:To investigate the status of frailty and activities of daily living (ADL) in maintenance hemodialysis (MHD) patients, and to explore the effect of frailty phenotype on ADL.Methods:The patients who underwent MHD in Kidney Disease Center of the First Affiliated Hospital from March 2019 to March 2020 were enrolled in this study. The demographic and laboratorial data were collected by cross-sectional survey method. Fried frailty phenotype scale and ADL scale were used to evaluate the frailty and ADL, respectively. The differences of basic data and different frailty phenotypes between the normal function group and the function decline group were compared in terms of ADL, physical self-maintenance ability and instrumental ADL ability. Pearson correlation analysis was used to analyze the correlation between frailty and ADL, and binary logistic regression analysis was used to analyze the influencing factors of ADL.Results:A total of 676 MHD patients were included in this study, including 434 males (64.2%) and 242 females (35.8%). The age was (59.2±19.4) years old, and the median dialysis age was 59.0 (25.3, 110.0) months. There were 159 frailty patients (23.5%), 230 pre-frailty patients (34.0%), and 287 non-frailty patients (42.5%). The ADL was decreased in 163 patients (24.1%), including 131 patients (19.4%) with decreased physical self-maintenance ability and 161 patients (23.8%) with decreased instrumental ADL ability. Pearson correlation analysis showed that the frailty score was positively correlated with total ADL score ( r=0.728, P<0.001), physical self-maintenance ability score ( r=0.669, P<0.001) and instrumental ADL ability score ( r=0.729, P<0.001). Binary logistic regression analysis results showed that older age and lower physical activity, fatigue, slowed steps and lower grip strength in the frailty phenotypes were the independent influencing factors of ADL, physical self-maintenance ability and instrumental ADL ability (all P<0.05). Conclusions:The prevalence of frailty is 23.5% in MHD patients, and 24.1% of MHD patients have decreased ADL. Elder age and lower physical activity, fatigue, reduced step counts, and lower grip strength in frailty phenotypes are the independent influencing factors for poor ADL, poor physical self-maintenance ability and poor instrumental ADL ability.
ABSTRACT
Chitinase has a wide industrial application prospect. For example, it can degrade shrimp shells, crab shells and other crustacean waste into high value-added chitooligosaccharides. However, the low catalytic efficiency of chitinase greatly limits the production of chitooligosaccharides. In previous study, the we expressed a chitinase Chisb with high catalytic efficiency and studied its enzymatic properties. In order to further improve the catalytic efficiency of Chisb, with R13NprB-C-SP-H as the parent, here error-prone PCR was used to construct random mutant library to conduct directed evolution of chitinase Chisb. Two mutants C43D and E336R were obtained with 96-well plate primary screening and shaker-screening, and their enzymatic properties were also studied. The optimum temperature of C43D and E336R was 55 °C, and the optimum pH of C43D was 5.0, while that of E336R was 9.0. The catalytic efficiency of C43D and E336R was 1.35 times and 1.57 times higher than that of control. The chitooligosaccharide concentration of E336R and C43D was 2.53 g/L and 2.06 g/L, improved by 2.84 times and 2.31 times compared with the control (0.89 g/L), respectively. In addition, the substrate conversion rate of mutants E336R and C43D was 84.3% and 68.7%, improved by 54.6% and 39% compared with the control (29.7%), respectively. In summary, the study indicates that random mutation introduced by error-prone PCR can effectively improve the catalytic efficiency of chitinase Chisb. The positive mutants with higher catalytic efficiency obtained in the above study and their enzymatic property analysis have important research significance and application value for the biosynthesis of chitooligosaccharides.