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:

Remodelling of nerve structure in experimental isoniazid neuropathy in the rat. The neuropathy caused by a single dose of isoniazid in rats was studied with a computer-assisted morphometric method. Scatter diagrams of the g ratio (quotient fibre diameter/axon diameter) define regenerating fibres as a distinct population, distinguishable from the surviving fibres by reduced sheath thickness and reduced axon calibre. There was also evidence of a subtle direct toxic effect on the entire fibre population, causing axon shrinkage masked by readjustment of the myelin sheath.
{"Chemical": ["isoniazid"], "Disease": ["neuropathy"]}