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:

Hepatic veno-occlusive disease caused by 6-thioguanine. Clinically reversible veno-occlusive disease of the liver developed in a 23-year-old man with acute lymphocytic leukemia after 10 months of maintenance therapy with 6-thioguanine. Serial liver biopsies showed the development and resolution of intense sinusoidal engorgement. Although this disease was clinically reversible, some subintimal fibrosis about the terminal hepatic veins persisted. This case presented a unique opportunity to observe the histologic features of clinically reversible hepatic veno-occlusive disease over time, and may be the first case of veno-occlusive related solely to 6-thioguanine.
{"Chemical": ["6-thioguanine"], "Disease": ["veno-occlusive disease of the liver", "Hepatic veno-occlusive disease", "hepatic veno-occlusive disease", "acute lymphocytic leukemia", "fibrosis"]}