Objective:To explore the postprandial plasma low-density lipoprotein cholesterol (LDL-C) changes by various detection methods.Methods:A total of 85 subjects admitted to the Second Xiangya Hospital of Central South University from November 2017 to May 2019 were included. Serum samples were collected from fasting and the 2 nd hour and the 4 th hour after breakfast. Serum lipid levels were measured with enzymatic assays and nuclear magnetic resonance spectroscopy (NMRS), and proprotein invertase subtilisin/kexin type 9 (PCSK9) levels were measured with enzyme-linked immunosorbent assays. The differences of blood lipid components at different time points were compared by Friedman two-way rank analysis of variance and Wilcoxon signed rank test, and the correlation between PCSK9 level and lipoprotein particles was analyzed by Spearman correlation. Results:Measured by enzymatic assays, compared with the fasting state, LDL-C decreased at the 2 nd hour and the 4 th hour after the meal (2.58[2.09, 3.12], 2.47[1.92, 3.02], 2.37[1.82, 2.80] mmol/L, P<0.001). Measured by NMRS, the concentration of LDL particles (1 086[830, 1 239], 1 083[848, 1 213], 1 061[814, 1 213] nmol/L, P=0.417) did not change significantly, and cholesterol in LDL particles were 2.13 (1.56, 2.54), 2.16 (1.68, 2.50), 2.06 (1.58, 2.50) mmol/L, respectively ( P=0.047)，and postprandial cholesterol in LDL particles in the 2 nd hour and in the 4 th hour did not change significantly compared with fasting ( P>0.05). while the concentration of large LDL particles (185.2[150.6,221.6], 173.0[144.8,220.3], 178.1[144.0,233.6] nmol/L, P=0.001), and the cholesterol level in large LDL particles (0.49[0.39, 0.57], 0.47[0.38, 0.57], 0.46[0.37, 0.58]mmol/L, P<0.001) decreased after the meal. The PCSK9 level also decreased significantly after the meal (299[233, 397], 257[208, 342], 251[215, 340] ng/ml, P<0.001). There was an independent positive correlation between the decrease of PCSK9 levels and the increase of remnant cholesterol detected by MNRS after the meal ( r=0.232, P=0.035). Conclusions:The postprandial LDL-C level measured by NMRS and enzymatic assays is not consistent. The decrease of LDL-C measured by enzymatic assays is not caused by the clearance of LDL particles, but by the redistribution of cholesterol in each LDL subfraction.

In the context of the "Belt and Road" initiative, We systematically analyzed the general education and training systems of 16 Western Pacific countries and regions, including general practitioner college education, post-graduation education, and faculty status. Developed countries and regions have a long-term medical education system, strong faculty, and a comprehensive training model for general practitioners. Underdeveloped countries and regions are relatively weak in educational institutions, faculty, and general practitioner training models. The underdeveloped countries and regions should develop a general medical education and training system in terms of strengthening the construction of general medical disciplines, strengthening the supervision and certification of general practitioners, improving the general medical training model, and strengthening the construction of teachers.