AIM: To evaluate the effect of captopril on action potential duration and outward delayed rectification potassium current (Ik). METHODS: Action potentials were recorded using a conventional glass microelectrode filled with 3 mol/L KCl solution. Membrane patch clamp whole cell recording technique was used to investigate the Ik current maximum in the holding potential - 50 mV, lasting time 100 ms, command potential + 40 mV. RESULTS: The action potential duration of 30%, 50% repolarization (APD30, APD50) and ERP were significantly prolonged, but APD90 wasn' t prolonged significantly when captopril group compared with ischemic group. The amplitude of Ik increased significantly in ischemic group, but significantly decreased in captopril group and in captopril + ischemic group. The shapes of current - voltage relationship were unchanged among groups, but significantly upward in ischemic group and downward in captopril and captopril + ischemic group. CONCLUSION:Captopril exerts electrophysiologic action due to decreasing delay outward rectification potassium current and prolonging action potential duration of APD30, APD50 and ERP.

Objective To investigate clinical treatment status in early hospitalized patients with acute ST-segment elevated myocardial infarction(STEMI).Methods The data of hospitalized patients with STEMI admitted between January 2001 and June 2005 were retrospectively collected and studied from medical records of the 2nd Hospital of Tianjin Medical University.Results A total of 773 cases were investigated,71.80% of the patients were male,the median age was 66.0 years,and the hospitalization duration was 11.0 days.The median duration from the onset of STEMI to the arrival in the wards was 210 min.The median initiation time of door-to-needle or door-to-balloon treatment for reperfusion therapy was 60 and 100 minutes,respectively.As to the selection of the reperfusion strategies,patients who were male,younger(age

AIM: To understand whether reactive oxygen species promote the rupture of atherosclerotic plaques by regulating the balance of matrix metalloproteinase-1,3 (MMP-1,3) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in smooth muscle cells. METHODS: Aortic smooth muscle cells from 4-6months-healthy abortive fetuses were incubated for 24 hours with xanthine (100 ?mol/L) and xanthine oxidase (5 U/L) in vitro . MMP-1,3 and TIMP-1 in the concentrated culture media were measured by Western blotting ( n =3 independent experiments). RESULTS: Incubation with xanthine/xanthine oxdiase decreased the amount of MMP-1 in the aortic smooth muscle cells (21.2%?5.5% of the control group),and pro-MMP-1 was activated completely. Reactive oxygen species (ROS) also activated pro-MMP-3,and increased the production of MMP-3 in the aortic smooth muscle cells. On the other hand,ROS inhibited the production of TIMP-1 in the aortic smooth muscle cells. CONCLUSION: It is complicated that ROS regulates the balance of MMPs and TIMPs. ROS may contribute to matrix degradation and the rupture in the atherosclerotic plaques.

Objective To evaluate the clinical characteristics and in-hospital mortality of acute myocardial infarction patients (AMI) with diabetes mellitus (DM) and to analyze the risk factors of in-hospital mortality of AMI. Method A total of 1023 patients with diagnosis of AMI complicated with or without DM admitted between 2000 and 2004 were analyzed to find out the clinical characteristics, in-hospital complications and mortality. Of them, 164 (16.03%) were complicated with DM. The data were analyzed by using Mann-Whitney U or chi-square test. The multivariate logistic regression analysis was used to find out the risk factors of in-hospital mortality of patient with AMI. Results In comparison with non-DM patients, the females were predominant in number over males in the DM patient cohort (42.2% vs. 28.9%, P < 0.05), the incidence of hypertension (71.7% vs. 41.6%, P < 0.01) and rate of angina (57.3% vs. 48.3%, P < 0.06). The admission time of DM patients was delayed rather than that of non-DM patients. Coronary angiography revealed that the rate of three-vessel in-volved was higher in DM patients than in non-DM patients (48.4% vs. 25.4%, P < 0.05. During hospital stay, AMI patients with DM presented mar frequently with arrhythmias, pulmonary edema (18.9% vs. 10.5%, P <0.01) and increase in in-hospital mortality (17.7% vs. 9.2%, P < 0.01) compared with non-DM patients. Di-uretics (43.9% vs. 32%, P <0.01) and digitalis (27.4% vs. 16.8%, P <0.01) were more frequently used in DM patients rather than in non-DM patients. Compared to medication, primary coronary intervention (PCI) with placement of intra-vascular stent significantly decreased the mortality of DM patients (χ~2 = 4.536, P < 0.05).Logistic regression analysis showed DM was an independent risk factor for in-hospital mortality (OR = 2.109;95% CI:1.229-3.619). Conclusions AMI patients with DM exhibit more risk factors for in-hospital complications and higher mortality than those without DM.DM is an independent risk factor for in-hospital mortality of patients with AMI.