ObjectiveTo investigate the association of angiotensin converting enzyme(ACE) gene polymorphism and its serum levels with cerebral infarction, and further to explore its possible mechanism. MethodsEighty-four patients with cerebral infarction(cerebral infarction group) and 74 healthy controls(healthy control group) underwent the determination of ACE gene insertion/deletion polymorphism by polymerase chain reaction(PCR) and agarose gel electrophoresis(AGE). The serum levels of ACE were measured simultaneously. The difference in distribution of ACE gene polymorphism was compared between cerebral infarction group and ealthy control group. ResultsThe frequency of DD genotype in cerebral infarction group was significantly higher than that of healthy control group(50% vs 28% ,P<0.01); so was the frequency of D allele(64% vs 46% ,P<0.05). ACE gene polymorphism was associated with the serum level of ACE. A significant difference in serum ACE level was observed among three ACE genotypes. The highest serum ACE level or activity was in deletion homozygote(genotype DD), followed by heterzygote(genotype ID) and insertion homozygote(genotype Ⅱ)(P<0.01). ConclusionThe polyrnorphism of ACE gene and serum level of ACE are associated with cerebral infarction. The DD gene type of ACE and D allele may be the risk factor for cerebral infarction.

ObjectiveTo investigate the effect of hypoxia-inducible factor-1α (HIF-1α) on the stemness and epirubicin sensitivity of hepatoma cells. MethodsHepatoma cells were selected for experiment. HepG2 hepatoma cells transfected with HIF-1α overexpression plasmid were selected as experimental group, and those transfected with pcDNA3.1 empty plasmid were selected as control group; HepG2 cells alone were selected as HepG2 group. Quantitative real-time PCR was used to measure the mRNA expression of HIF-1α; Western blot was used to measure the protein expression of HIF-1α; flow cytometry was used to measure the expression of CD133 on the surface of hepatoma cells. The three groups of cells were treated with epirubicin at different concentrations (0, 6.25, 12.5, 25, and 50 μmol/L) for 24 hours; MTT assay was used to measure cell viability, and flow cytometry was used to measure apoptosis after treatment with epirubicin (50 μmol/L). A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the t-test was used for further comparison between two groups. ResultsCompared with the HepG2 group and the control group, the experimental group had a significant increase in the mRNA expression of HIF-1α (both P＜0.001), and Western blot showed high expression of HIF-1α in the experimental group. The percentage of CD133 cells was 0.040%±0.003% in the HepG2 group, 0.030%±0.010% in the control group, and 20.110%±0.600% in the experimental group, and the experimental group had a significantly higher positive rate of CD133+ than the HepG2 group and the control group (both P＜0.001). At an epirubicin concentration of 25 and 50 μmol/L, the HepG2 group and the control group had significantly inhibited cell viability and a significantly lower cell viability than the experimental group (both P＜005). After the treatment with 50 μmol/L epirubicin for 48 hours, the experimental group had a significantly lower cell apoptosis rate than the HepG2 group (67.9%±2.5% vs 93.6%±1.5%, P＜0.001) and the control group (67.9%±2.5% vs 93.0%±1.2%, P＜0001). ConclusionHepG2 cells are successfully transfected with HIF-1α overexpression plasmid, and HIF-1α can increase the percentage of liver cancer stem cells and improve their resistance to epirubicin.