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: ["Chemical"].

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

Environmental pesticide exposure modulates cytokines, arginase and ornithine decarboxylase expression in human placenta. To evaluate the cytokine balance and enzymatic alterations induced by environmental pesticide exposure during pregnancy, this transversal study explored placentas derived from non-exposed women (control group-CG), and from women living in a rural area (rural group-RG), collected during intensive organophosphate (OP) pesticide spraying season (RG-SS) and during non-spraying season (RG-NSS). The exposure biomarkers blood cholinesterase and placental carboxylesterase (CaE) were significantly decreased in RG-SS. Among the cytokines studied IL-8, IL-6, TNFα, IL-10, TGFβ and IL-13, the expression frequency of IL-13 increased in RG-SS. Arginase and ornithine decarboxylase (ODC) enzymes were induced in syncytiotrophoblast and endothelial cells. Interestingly, the decrease in CaE activity was associated with arginase and ODC activity induction. These findings suggest that environmental pesticide exposure impacts the placenta by increasing the expression frequency of the anti-inflammatory cytokine IL-13, which may be related to the up-regulation of enzymes implicated in tissue repair.
{"Chemical": ["organophosphate", "ornithine"]}