BACKGROUND:The siphon of internal carotid artery is a complex of bending and surrounding structure, which has become a research hot in the field of medical imaging and regional anatomy. There is little research on the hemodynamics of internal carotid artery. Finite element analysis provides the basis for the related dynamics research. OBJECTIVE:To explicit the hemodynamic characteristics of the normal and stenosis internal carotid artery, and to explore the relevant influential factors. METHODS:Finite element model of the siphon of internal carotid artery was built based on 64-slice spiral CT data, and then, three-dimensional models were constructed using Mimics 10.01 software. There were simulations of the normal and post-stenosis blood flows with ANSYS 13.0 CFX software, to observe the changes of hemodynamics, and to analyze their characteristics and differences. RESULTS AND CONCLUSION:The normal blood flow at the siphon of internal carotid artery was in a laminar state, but rotation and turbulent flow formed at the two angle regions. The velocity of external bending zone was slower than that of the internal. The slower was the velocity, the more obvious was the turbulence. The wal shear force decreased at the angle regions, and the wal shear force of external bending zone was smal er than that of the internal. At the region of arterial stenosis, the blood flow was sped, and at the downstream, turbulent flow and low zone of wal shear force were formed. With the increase of stenosis severity, the turbulent flow and low wal shear force area were expanded. Central stenosis showed more obvious effects than the eccentric one. The degree of stenosis and bending at the siphon of internal carotid artery can directly influence the formation of turbulent flow and low wal shear force area, which are more obvious at the external bending zone and central stenosis.

Objective·To investigate the relation between urinary excretion of protein-bound uremic toxins(PBUTs)and upper urinary tract calculus.Methods·Residents aged 18?80 years in the community of Haitou,Danzhou city in Hainan Province were recruited.Basic information and diet for the last 3 d of the subjects were recorded.Their fasting sera and 24-hour urine samples were collected,and they also underwent ultrasound examination of kidneys and ureters.The subjects with upper urinary calculi detected by ultrasound or a clear history of upper urinary calculi were selected as the calculus group,and the others as the non-calculus group.The biochemical indicators related to the formation of calculus in blood and urine were detected,and the levels of PBUTs,including indoxyl sufate(IS),indole-3-acetic acid(IAA),and p-cresol sulfate(PCS)in blood and urine,as well as oxalic acid and citric acid in urine were detected by high-performance liquid chromatography.The related factors of upper urinary tract calculus formation were analyzed by multivariate Logistic regression.The correlations of urine PBUTs with urine uric acid,oxalic acid,and citric acid were analyzed by Spearman correlation test.Results·A total of 117 participants were screened out with 54 people in the calculus group and 63 people in the non-calculus group.There were no significant differences between the two groups in terms of gender,age,serum indicators,and prevalence of complications such as hypertension,diabetes,and hyperuricemia/gout.The 24-hour urine pH,calcium,uric acid,and chlorine in the calculus group were significantly higher than those in the non-calculus group(all P<0.05),while IS was significantly lower than that in the non-calculus group(P<0.05).Multivariate Logistic regression analysis showed that urinary IS(OR=0.929,95%CI 0.875?0.986,P=0.016)was related to the calculus formation independently,in addition to urinary calcium.The Spearman correlation analysis results showed that the levels of IAA(r=0.420,P=0.000)and PCS(r=0.307,P=0.001)in 24-hour urine were positively correlated with oxalic acid,PCS was positively correlated with uric acid(r=0.297,P=0.002),and IS was positively correlated with citric acid(r=0.289,P=0.002).Conclusion·In the population,a decrease in urinary excretion of IS may be an independent risk factor for the formation of upper urinary tract calculus,and PBUTs levels are correlated with levels of uric acid,oxalic acid,and citric acid.

Based on the discussions in the The Inner Canon of Yellow Emperor （《黄帝内经》）， it is proposed that in the course of the disease， "bind" represents the initial stage of pulmonary nodules， while "accumulation" represents the final form. In terms of the pathogenesis， "two colds interacting" represented by "body cold" and "cold fluid retention" are the prerequisites for the formation of pulmonary nodules， while "disorder of qi" represented by "fainting" is the core of the formation. The specific manifestation is the disturbance of pivot of shaoyang （少阳） or shaoyin （少阴）， resulting in a complex of cold and heat， and then phlegm and stasis are suddenly generated and further formed into nodules. Therefore， the treatment principle should be to regulate the cardinal mechanism， dissolve phlegm and blood stasis. Depending on the complex degree of cold and heat， it is suggested to use Chaihu Guizhi Decoction （柴胡桂枝汤）， Chaihu Guizhi Ganjiang Decoction （柴胡桂枝干姜汤）， or Chaihu Xianxiong Decoction （柴胡陷胸汤） for disturbance of shaoyang pivot， while for shaoyin pivot dysfunction， modified Mahuang Fuzi Xixin Decoction （麻黄附子细辛汤） or Shengjiang Powder （升降散） can be used.