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A rat hypoxia model, and the reversal of muscularisation is partial.\nexposure: Sildenafil 25 or 75 milligrams per kilogram per day started before hypoxia, or started after 14 days of established pulmonary hypertension\nevidence_span: {\"source_cache\": \"artifacts/sildenafil-research/12796132.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"61d9020b6275a7c57fcee753c74b06c334ad034286eeaccdcbdf12e49b472122\", \"start_char\": 0, \"end_char\": 1616, \"text_sha256\": \"61d9020b6275a7c57fcee753c74b06c334ad034286eeaccdcbdf12e49b472122\"}\n[sil-p12796132] Phosphodiesterase type 5 as a target for the treatment of hypoxia-induced pulmonary hypertension. 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