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: ["Protein", "Chemical"].

Please return the output as a JSON object of the format: {"Chemical" : ["Dexamethasone", ...], "Protein" : ["BRCA-1", ...]}. 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:

Serotonin 5-HT(2B) receptor loss of function mutation in a patient with fenfluramine-associated primary pulmonary hypertension.
OBJECTIVE: Appetite-suppressant drug fenfluramine is implicated in primary pulmonary hypertension (PPH) but the molecular pathways that mediate this effect are unknown. A mouse model incriminates the serotonin 5-HT(2B) receptor but contrasts with other models where this receptor has been shown to mediate pulmonary arterial relaxation via nitric oxide production. METHODS: We analyzed the human 5-HT(2B) gene in 10 patients with appetite-suppressant drug-associated PPH. RESULTS: A mutation causing premature truncation of the protein product was found in one patient. The mutation was not found in 80 control subjects and no 5-HT(2B) mutation was found in 18 PPH patients not associated with appetite-suppressants. Functional analysis of the transfected receptor expressed either transiently in COS cells or stably in CHO cells demonstrated that the mutated receptor fails to activate the second messenger inositol-phosphates cascade and subsequent intracellular calcium release, in spite of normal expression at the cell membrane. The mutated receptor had no constitutive activity, and produced no dominant negative effect on the wild-type receptor. CONCLUSION: Loss of serotonin 5-HT(2B) receptor function may predispose to fenfluramine-associated PPH in man.
{"Chemical": ["serotonin", "fenfluramine", "CHO", "calcium", "Serotonin", "inositol-phosphates", "nitric oxide"], "Protein": ["Serotonin 5-HT(2B) receptor", "human 5-HT(2B)", "5-HT(2B) receptor", "serotonin 5-HT(2B) receptor", "5-HT(2B)"]}