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: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. 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:

Coronary microvascular function in patients with Cushing's syndrome. The aim of the study was to evaluate patients with Cushing's syndrome the coronary flow reserve (CFR), an index of coronary microvascular function. Fifteen newly diagnosed patients with Cushing's syndrome (1 male/14 females; mean age 45 ± 11 years), were selected for having no clinical evidence of ischemic heart disease. Twelve patients had pituitary-dependent Cushing's disease and three had an adrenal adenoma. Fifteen subjects matched for age, sex, and major cardiovascular risk factors were used as controls. Coronary flow velocity in the left anterior descending coronary artery was investigated by transthoracic Doppler echocardiography at rest and during adenosine infusion. CFR was obtained as the ratio hyperemic/resting diastolic flow velocity. A reduced coronary reserve (hyperemic/resting ratio ≤ 2.5) was found in 5/15 Cushing patients and 4/15 controls. In all patients with abnormal CFR, epicardial coronary stenosis was excluded by multi-slice computed tomographic coronary angiography. CFR was inversely related to urinary cortisol in patients with endogenous hypercortisolism (Spearman's rho = -0.57, P = 0.03), while no correlation was found in controls. Coronary microvascular function, as assessed by CFR, is pathologically reduced in a considerable number of patients with Cushing's syndrome without clinical symptoms of ischemic heart disease and in the absence of epicardial coronary artery lesions, as well as in controls matched for cardiovascular risk factors. The presence of comorbidities can explain this early coronary abnormality in both patients and controls. Whether urinary cortisol may be a predictor of coronary microvascular function in the setting of patients with Cushing's syndrome, needs further investigation.
{"Chemical": ["cortisol", "adenosine"]}