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: ["Disease", "Chemical"].

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

Selective injection of iopentol, iohexol and metrizoate into the left coronary artery of the dog. Induction of ventricular fibrillation and decrease of aortic pressure. In twenty beagle dogs selective injections were made into the left coronary artery with iopentol, iohexol and metrizoate in doses of 4 ml, 8 ml and 16 ml. Thirty-six iopentol injections, 35 iohexol injections and 37 metrizoate injections were made. Frequencies of ventricular fibrillation were significantly lower (p less than 0.05) after iopentol (0%) and iohexol (3%) than after metrizoate (22%). Iopentol and iohexol also produced significantly less decrease in aortic blood pressure than metrizoate at the different doses.
{"Chemical": ["iopentol", "metrizoate", "iohexol", "Iopentol"], "Disease": ["ventricular fibrillation"]}