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:

Value of methylprednisolone in prevention of the arthralgia-myalgia syndrome associated with the total dose infusion of iron dextran: a double blind randomized trial. The safety and efficacy of total dose infusion (TDI) of iron dextran has been well documented. In 40% of treated patients, an arthralgia-myalgia syndrome develops. The purpose of this randomized, double-blind, prospective study was to investigate whether intravenous (i.v.) administration of methylprednisolone (MP) prevents this complication. Sixty-five patients, 34 women and 31 men, ages 36 to 80 years, received either normal saline before and after TDI (group 1), 125 mg i.v. MP before and saline after TDI (group 2), or 125 mg i.v. MP before and after TDI (group 3). Patients were observed for 72 hours and reactions were recorded and graded according to severity. Fifty-eight percent of group 1 patients, 33% of group 2, and 26% of group 3 had reactions to TDI. The severity of reactions (minimal, mild, and moderate, respectively) was as follows: group 1--6, 6, and 2; group 2--1, 5, and 0; group 3--5, 1, and 0. Data were analyzed by the two-sided Fisher's exact test using 95% confidence intervals with the approximation of Woolf. These data demonstrate that administration of MP before and after TDI reduces the frequency and severity of the arthralgia-myalgia syndrome. We conclude that 125 mg i.v. MP should be given routinely before and after TDI of iron dextran.
{"Chemical": ["MP", "iron dextran", "methylprednisolone"], "Disease": ["arthralgia", "myalgia"]}