You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

The effects of the angiotensin-converting enzyme inhibitor imidapril on plasma plasminogen activator inhibitor activity in patients with acute myocardial infarction . This study sought to determine whether early treatment with angiotensin-converting enzyme ( ACE ) inhibitors in patients with acute myocardial infarction ( AMI ) is useful for the improvement of fibrinolytic function , as well as left ventricular function . This study was designed to examine the levels of plasma plasminogen activator inhibitor ( PAI ) activity and serum ACE activity during the course of 2 weeks in 40 patients with AMI within 12 hours after the onset of the symptom and who randomly received early treatment with either the ACE inhibitor imidapril or a placebo ( 20 patients in the imidapril group and 20 in the placebo group ) . The levels of serum ACE activity in the imidapril group decreased significantly ( p < 0.01 ) 8 hours after the administration of imidapril , and the levels 24 hours after administration were significantly lower than those in the placebo group ( 3.6 +/- 0.6 IU/L vs 7.4 +/- 0.8 IU/L ; p < 0.001 ) . The plasma PAI activity increased gradually to peak levels 16 hours after the administration of imidapril and placebo . The levels in the placebo group decreased gradually but remained high during the study period . On the other hand , the levels of PAI activity in the imidapril group decreased rapidly and those 48 hours after administration were significantly lower than those in the placebo group ( 7.9 +/- 1.9 IU/ml vs 18.4 +/- 3.5 IU/ml ; p < 0.01 ) . The levels of left ventricular ejection fraction about 2 weeks after admission were significantly higher in the imidapril group than in the placebo group ( 65.9 % +/- 2.5 % vs 49.1 % +/- 4.4 % ; p < 0.01 ) . This study showed that imidapril , an ACE inhibitor , might be useful for the improvement of fibrinolytic function and left ventricular function in the acute phase of myocardial infarction .
{"Intervention": ["ACE inhibitor imidapril", "placebo", "angiotensin-converting enzyme ( ACE ) inhibitors", "imidapril", "angiotensin-converting enzyme inhibitor imidapril"], "Outcome": ["levels of PAI activity", "serum ACE activity", "plasma PAI activity", "levels of left ventricular ejection fraction", "levels of serum ACE activity", "left ventricular function", "fibrinolytic function", "plasma plasminogen activator inhibitor ( PAI ) activity"], "Participant": ["40", "20", "AMI", "acute myocardial infarction"]}