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:

Combined delivery approach of bone marrow mononuclear stem cells early and late after myocardial infarction : the MYSTAR prospective , randomized study . BACKGROUND Combined intracoronary and intramyocardial administration might improve outcomes for bone-marrow-derived stem cell therapy for acute myocardial infarction ( AMI ) . We compared the safety and feasibility of early and late delivery of stem cells with combined therapy approaches . METHODS Patients with left ventricular ejection fraction less than 45 % after AMI were randomly assigned stem cell delivery via intramyocardial injection and intracoronary infusion 3-6 weeks or 3-4 months after AMI . Primary end points were changes in infarct size and left ventricular ejection fraction 3 months after therapy . RESULTS A total of 60 patients were treated . The mean changes in infarct size at 3 months were -3.5 +/- 5.1 % ( 95 % CI -5.5 % to -1.5 % , P = 0.001 ) in the early group and -3.9 +/- 5.6 % ( 95 % CI -6.1 % to -1.6 % , P = 0.002 ) in the late group , and changes in ejection fraction were 3.5 +/- 5.6 % ( 95 % CI 1.3-5.6 % , P = 0.003 ) and 3.4 +/- 7.0 % ( 95 % CI 0.7-6.1 % , P = 0.017 ) , respectively . At 9-12 months after AMI , ejection fraction remained significantly higher than at baseline in both groups . In the early and late groups , a mean of 200.3 +/- 68.7 x 10 ( 6 ) and 194.8 +/- 60.4 x 10 ( 6 ) stem cells , respectively , were delivered to the myocardium , and 1.30 +/- 0.68 x 10 ( 9 ) and 1.29 +/- 0.41 x 10 ( 9 ) cells , respectively , were delivered into the artery . A high number of cells was required for significant improvements in the primary end points . CONCLUSIONS Combined cardiac stem cell delivery induces a moderate but significant improvement in myocardial infarct size and left ventricular function .
{"Intervention": ["cardiac stem cell delivery", "bone-marrow-derived stem cell therapy", "Combined delivery approach", "intracoronary infusion 3-6 weeks or 3-4 months after AMI", "stem cell delivery", "intramyocardial injection", "bone marrow mononuclear stem cells early", "stem cells"], "Outcome": ["number of cells", "and", "left ventricular ejection fraction 3 months after therapy", "myocardial infarct size", "stem cells", "safety and feasibility", "ejection fraction", "left ventricular function", "changes in infarct size", "changes in ejection fraction", "mean changes in infarct size at 3 months"], "Participant": ["60", "left ventricular ejection fraction less than 45 % after AMI", "myocardial infarction"]}