An RNase P ribozyme library has been developed as a tool for functional genomics studies. Each clone of this library contains a random 18-mer and the sequence of M1 RNA, the catalytic subunit of RNase P. Repression of target gene expression is thus achieved by the complementary binding of mRNA to the random guide sequence and the successive target cleavage via M1 RNA. Cellular expression of the ribozyme expression was confirmed, and EGFP mRNA was used as a model to demonstrate that the RNase P ribozyme expression system can inhibit the target gene expression. The constructed RNase P ribozyme library has a complexity of 1.4x10(7). This novel library system should become a useful in functional genomics, to identify novel gene functions in mammalian cells.
Catalytic Domain ; Clone Cells ; Gene Expression ; Genomics* ; Repression, Psychology ; Ribonuclease P* ; Ribonucleases* ; RNA ; RNA, Messenger

The optimal dose of beta blockers after acute myocardial infarction (MI) remains uncertain. We evaluated the effectiveness of low-dose nebivolol, a beta1 blocker and a vasodilator, in patients with acute MI. A total of 625 patients with acute MI from 14 teaching hospitals in Korea were divided into 2 groups according to the dose of nebivolol (nebistol®, Elyson Pharmaceutical Co., Ltd., Seoul, Korea): low-dose group (1.25 mg daily, n=219) and usual- to high-dose group (≥2.5 mg daily, n=406). The primary endpoints were major adverse cardiac and cerebrovascular events (MACCE, composite of death from any cause, non-fatal MI, stroke, repeat revascularization, rehospitalization for unstable angina or heart failure) at 12 months. After adjustment using inverse probability of treatment weighting, the rates of MACCE were not different between the low-dose and the usual- to high-dose groups (2.8% and 3.1%, respectively; hazard ratio: 0.92, 95% confidence interval: 0.38 to 2.24, p=0.860). The low-dose nebivolol group showed higher rates of MI than the usual- to high-dose group (1.2% and 0%, p=0.008). The 2 groups had similar rates of death from any cause (1.1% and 0.3%, p=0.273), stroke (0.4% and 1.1%, p=0.384), repeat PCI (1.2% and 0.8%, p=0.428), rehospitalization for unstable angina (1.2% and 1.0%, p=0.743) and for heart failure (0.6% and 0.7%, p=0.832). In patients with acute MI, the rates of MACCE for low-dose and usual- to high-dose nebivolol were not significantly different at 12-month follow-up.

BACKGROUND AND OBJECTIVES: There is a paucity of data regarding the benefit of clopidogrel monotherapy after dual antiplatelet therapy (DAPT) in patients treated with drug-eluting stents (DES). This study compared outcome between clopidogrel versus aspirin as monotherapy after DES for acute myocardial infarction (MI).METHODS: From Korea Acute Myocardial Infarction Registry-National Institute of Health database, 1,819 patients treated with DES who were switched to monotherapy with clopidogrel (n=534) or aspirin (n=1,285) after uneventful 12-month DAPT were analyzed. The primary endpoint was net adverse clinical events (NACE), defined as a composite of death from any cause, MI, repeat percutaneous coronary intervention (PCI), stent thrombosis, ischemic stroke, or major bleeding during the period from 12 to 24 months.RESULTS: After adjustment using inverse probability of treatment weighting, patients who received clopidogrel, compared with those treated with aspirin, had a similar incidence of NACE (0.7% and 0.7%; hazard ratio, 1.06; 95% confidence interval, 0.31–3.60; p=0.923). The 2 groups had similar rates of death from any cause (0.1% in each group, p=0.789), MI (0.3% and 0.1%, respectively; p=0.226), repeat PCI (0.1% and 0.3%, respectively; p=0.548), stent thrombosis (0.1% and 0%, respectively; p=0.121), major bleeding (0.2% in each group, p=0.974), and major adverse cardiovascular and cerebrovascular events (0.5% in each group, p=0.924).CONCLUSIONS: Monotherapy with clopidogrel, compared to aspirin, after DAPT showed similar clinical outcomes in patients with acute MI treated with DES.
Aspirin ; Drug-Eluting Stents ; Hemorrhage ; Humans ; Incidence ; Korea ; Myocardial Infarction ; Percutaneous Coronary Intervention ; Platelet Aggregation Inhibitors ; Stents ; Stroke ; Thrombosis

OBJECTIVE: Data on the intensity of statin therapy for patients with acute myocardial infarction (MI) and very low baseline low-density lipoprotein (LDL) cholesterol level are lacking. We sought to assess the impact of statin intensity in patients with acute MI and LDL cholesterol <70 mg/dL. METHODS: A total of 1,086 patients with acute MI and baseline LDL cholesterol <70 mg/dL from the Korea Acute Myocardial Infarction Registry-National Institute of Health database were divided into less intensive statin (expected LDL reduction <40%, n=302) and more intensive statin (expected LDL reduction ≥40%, n=784) groups. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCEs), a composite of cardiac death, MI, revascularization occurring at least 30 days after admission, and stroke, at 12 months. RESULTS: After 1:2 propensity matching, differences were not observed between less intensive (n=302) and more intensive statin (n=604) groups in incidence of cardiac death (0.3% vs. 0.3%) and hemorrhagic stroke (0.3% vs. 0.5%, p=0.727) at 12 months. Compared with the less intensive statin group, the more intensive statin group showed lower target-vessel revascularization (4.6% vs. 1.8%, p=0.027) and MACCE (11.6% vs. 7.0%, p=0.021). Major bleeding was not different between less intensive and more intensive statin groups (1.0% vs. 2.6%, p=0.118). CONCLUSION: More intensive statin therapy was associated with significantly lower major adverse cardiovascular events in patients with acute MI and very low LDL cholesterol compared with less intensive statin therapy.
Cholesterol ; Cholesterol, LDL ; Death ; Hemorrhage ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; Incidence ; Korea ; Lipoproteins ; Myocardial Infarction ; Stroke

Background/Aims: Minimising total ischemic time (TIT) is important for improving clinical outcomes in patients with ST-segment elevation myocardial infarction who have undergone percutaneous coronary intervention (PCI). TIT has not shown a significant improvement due to persistent pre-hospital delay. This study aimed to investigate the risk factors associated with pre-hospital delay. Methods: Individuals enrolled in the Korea Acute Myocardial Infarction Registry-National Institutes of Health between 2011 and 2015 were included in this study. The study population was analyzed according to the symptom-to-door time (STDT; within 60 or > 60 minutes), and according to the type of hospital visit (emergency medical services [EMS], non-PCI center, or PCI center). Results: A total of 4,874 patients were included in the analysis, of whom 28.4% arrived at the hospital within 60 minutes of symptom-onset. Old age (> 65 years), female gender, and renewed ischemia were independent predictors of delayed STDT. Utilising EMS was the only factor shown to reduce STDT within 60 minutes, even when cardiogenic shock was evident. The overall frequency of EMS utilisation was low (21.7%). Female gender was associated with not utilising EMS, whereas cardiogenic shock, previous myocardial infarction, familial history of ischemic heart disease, and off-hour visits were associated with utilising EMS. Conclusions Factors associated with delayed STDT and not utilising EMS could be targets for preventive intervention to improve STDT and TIT.

BACKGROUND AND OBJECTIVES: There is a paucity of data regarding the benefit of clopidogrel monotherapy after dual antiplatelet therapy (DAPT) in patients treated with drug-eluting stents (DES). This study compared outcome between clopidogrel versus aspirin as monotherapy after DES for acute myocardial infarction (MI). METHODS: From Korea Acute Myocardial Infarction Registry-National Institute of Health database, 1,819 patients treated with DES who were switched to monotherapy with clopidogrel (n=534) or aspirin (n=1,285) after uneventful 12-month DAPT were analyzed. The primary endpoint was net adverse clinical events (NACE), defined as a composite of death from any cause, MI, repeat percutaneous coronary intervention (PCI), stent thrombosis, ischemic stroke, or major bleeding during the period from 12 to 24 months. RESULTS: After adjustment using inverse probability of treatment weighting, patients who received clopidogrel, compared with those treated with aspirin, had a similar incidence of NACE (0.7% and 0.7%; hazard ratio, 1.06; 95% confidence interval, 0.31–3.60; p=0.923). The 2 groups had similar rates of death from any cause (0.1% in each group, p=0.789), MI (0.3% and 0.1%, respectively; p=0.226), repeat PCI (0.1% and 0.3%, respectively; p=0.548), stent thrombosis (0.1% and 0%, respectively; p=0.121), major bleeding (0.2% in each group, p=0.974), and major adverse cardiovascular and cerebrovascular events (0.5% in each group, p=0.924). CONCLUSIONS Monotherapy with clopidogrel, compared to aspirin, after DAPT showed similar clinical outcomes in patients with acute MI treated with DES.

Background/Aims: While switching strategies of P2Y12 receptor inhibitors (RIs) have sometimes been used in acute myocardial infarction (AMI) patients, the current status of in-hospital P2Y12RI switching remains unknown. Methods: Overall, 8,476 AMI patients who underwent successful revascularization from Korea Acute Myocardial Infarction Registry-National Institute of Health (KAMIR-NIH) were divided according to in-hospital P2Y12RI strategies, and net adverse cardiovascular events (NACEs), defined as a composite of cardiac death, non-fatal myocardial infarction (MI), stroke, or thrombolysis in myocardial infarction (TIMI) major bleeding during hospitalization were compared. Results: Patients with in-hospital P2Y12RI switching accounted for 16.5%, of which 867 patients were switched from clopidogrel to potent P2Y12RI (C-P) and 532 patients from potent P2Y12RI to clopidogrel (P-C). There were no differences in NACEs among the unchanged clopidogrel, the unchanged potent P2Y12RIs, and the P2Y12RI switching groups. However, compared to the unchanged clopidogrel group, the C-P group had a higher incidence of non-fatal MI, and the P-C group had a higher incidence of TIMI major bleeding. In clinical events of in-hospital P2Y12RI switching, 90.9% of non-fatal MI occurred during pre-switching clopidogrel administration, 60.7% of TIMI major bleeding was related to pre-switching P2Y12RIs, and 71.4% of TIMI major bleeding was related to potent P2Y12RIs. Only 21.6% of the P2Y12RI switching group switched to P2Y12RIs after a loading dose (LD); however, there were no differences in clinical events between patients with and without LD. Conclusions In-hospital P2Y12RI switching occurred occasionally, but had relatively similar clinical outcomes compared to unchanged P2Y12RIs in Korean AMI patients. Non-fatal MI and bleeding appeared to be mainly related to pre-switching P2Y12RIs.