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:

Hypotensive effects and influence on serum lipids of SQ29,852 , a new angiotensin converting enzyme inhibitor , in patients with essential hypertension : a comparison with atenolol . The effects of SQ29,852 ( n = 24 ) , a new angiotensin converting enzyme inhibitor , and atenolol ( n = 22 ) , monotherapies were compared in 46 patients with mild to moderate essential hypertension . Both SQ29,852 ( mean dose 15.0 +/- 5.1 mg/day ) and atenolol ( mean dose 37.5 +/- 18.5 mg/day ) significantly decreased both systolic and diastolic blood pressures . There were no significant changes in serum lipids , apolipoproteins , lipoproteins or atherosclerotic indices after both SQ29,852 and atenolol . There were also no significant inter-group differences . There were no serious side effects or abnormal laboratory tests in both treatment groups . It is concluded that SQ29,852 is an effective antihypertensive drug without adverse effect on lipid metabolism .
{"Intervention": ["angiotensin converting enzyme inhibitor", "SQ29,852 , a new angiotensin converting enzyme inhibitor", "SQ29,852", "atenolol"], "Outcome": ["serum lipids", "serious side effects or abnormal laboratory tests", "systolic and diastolic blood pressures", "adverse effect", "serum lipids , apolipoproteins , lipoproteins or atherosclerotic indices"], "Participant": ["patients with essential hypertension :"]}