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:

Low-dose clonidine administration in the treatment of mild or moderate essential hypertension : results from a double-blind placebo-controlled study ( Clobass ) . The Clobass Study Group . Five hundred and fifty-nine hypertensive outpatients with diastolic blood pressure between 95 and 110 mmHg participated in this double-blind , placebo-controlled , multicenter study . Eligible subjects were randomly allocated to receive either clonidine ( 75 micrograms twice daily ) or a placebo . After 4 weeks , 'responders ' to treatment ( diastolic blood pressure reduced to less than or equal to 90 mmHg or by greater than or equal to 10 mmHg ) were kept on monotherapy and checked at 4-weekly intervals for another 3 months . Non-responders were given 15 mg chlorthalidone and were also checked for a further 3 months . At the end of the first month , 54.2 % of the subjects were responders to clonidine and 41.5 % were responders to the placebo ( P less than 0.05 for both groups ) . Of the remaining patients , 69.0 % became responders to clonidine plus chlorthalidone , whereas only 34.7 % were responders to placebo plus chlorthalidone ( P less than 0.01 for both groups ) . Withdrawals from the study because of excessive diastolic blood pressure levels were about eight times less frequent among the subjects treated with clonidine , either alone or with chlorthalidone . Dry mouth was twice as frequent in the clonidine-treated patients , but there was no significant difference in the incidence of all side effects or the number of withdrawals from the study because of side effects between the two groups . We conclude that low-dose clonidine is effective in the treatment of mild or moderate hypertension . Clonidine-related side effects are still evident , but the overall tolerance profile for this reduced dosage of the drug appears to be favorable .
{"Intervention": ["clonidine-treated", "placebo .", "placebo", "monotherapy", "chlorthalidone .", "chlorthalidone", "placebo-controlled", "clonidine", "Clonidine-related"], "Outcome": ["number of withdrawals", "diastolic blood pressure", "Dry mouth", "side effects", "excessive diastolic blood pressure levels"], "Participant": ["Five hundred and fifty-nine", "outpatients with diastolic blood pressure between 95 and 110 mmHg", "mild or moderate essential hypertension"]}