ABSTRACT
Objective To investigate the relationship between low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (LHR) and asymptomatic carotid plaques and their stability in high-risk stroke population.Methods Between December 2012 and April 2015,a total of 39 944 permanent resident population ≥40 years were used as subjects of the survey from 11 rural communities in Haitou Town,Banzhuang Town and Tashan Town,Ganyu District,and 9 urban communities in Xinpu District and Haizhou District,Lianyungang City using epidemiological survey method of cluster sampling.Excluding those who took lipid-lowering drugs within 3 months and had a history of stroke or transient ischemic attack,6 592 people at high risk of stroke were finally screened out.Ultrasound was used to detect carotid plaques.The subjects were divided into plaque-free group and plaque group.The latter was further divided into stable plaque group and unstable plaque group.Multivariate logistic regression analysis was used to evaluate the independent risk factor for carotid plaques and their stability.The odds ratio (OR) and 95％ confidence interval (CI) were calculated.Receiver Operating Characteristic (ROC) curve was used to evaluate the prediction efficiency of LHR on carotid plaques.Results Multivariate logistic regression analysis showed that low-density lipoprotein cholesterol (LDL-C) was an independent risk factor for carotid plaques,while high-density lipoprotein cholesterol (HDL-C) was an independent protection factor of carotid plaques.Using the lowest quintile (Q1) of LHR as a reference,carotid plaque risk increased significantly with the increasing LHR (Q2:OR 1.448,95％ CI 1.082-1.937,P =0.013;Q3:OR 2.414,95％ CI 1.754-3.322,P＜0.001;Q4:OR 2.939,95％ CI 1.945-4.441,P＜0.001;Q5:OR 4.884,95％ CI 3.143-7.115,P＜0.001).ROC curve analysis showed that the area under the curve (AUC) of LHR predicting carotid plaques was 0.795 (95％ CI 0.792-0.807;P＜ 0.001),and the optimal cut-off value was 3.00 (sensitivity 68.37％,specificity 75.65％).LHR ≥3.92 (LHR in the Q4 and Q5 subgroups) was an independent risk factor for unstable carotid plaques (OR 2.915,95％ CI 2.104-4.040;P＜0.001).The AUC of the LHR predicting unstable carotid plaques was 0.658 (95％ CI 0.633-0.684;P＜0.001).Conclusions LHR was an independent predictor of carotid plaques in high-risk stroke patients.It had higher predictive value for carotid plaques,and its conversion threshold for promoting plaque formation was 3.00.When LHR was ≥3.92,there was a significant increase in the risk of unstable carotid plaques.
ABSTRACT
<p><b>BACKGROUND</b>To establish a SAH hydrolase antiviral screening in vitro model for screening of broad spectrum antiviral agents.</p><p><b>METHODS</b>SAH hydrolase was purified from rat livers by (NH4) 2SO4 fractionation, DEAE52,hydroxyapatite and Sephadex G-100 chromatography successively. The activity of SAH hydrolase was estimated by radio labeled substrate in synthesis direction by TLC.</p><p><b>RESULTS</b>Purified SAH hydrolase showed a single band in SDS-PAGE electrophoresis with silver nitrate staining, the apparent molecular weight is 45 000. The Km for adenosine is (6.32 +- 0.17) micromol/L. The IC50 of S-DNPA, a known inhibitor of SAH hydrolase, was 7.6 micromol/L estimated in our system. The structure and activity relationships shown by racemic and regiosomer analogs of S-DHPA indicated that the structural specificity of SAH hydrolase was high. 42 compounds had been screened in the system and no compound showed more inhibitory activity against SAH hydrolase than S-DNPA.</p><p><b>CONCLUSIONS</b>An in vitro antiviral screening model has been established using SAH hydrolase. It can also be used to study kinetics of enzyme inhibition.</p>