title: Effect of methylprednisolone on radiotherapy of F344 rats with avian sarcoma virus induced gliomas.
abstract: We have examined the impact of methylprednisolone acetate (MPA) on survival of F344 rats that were bearing avian sarcoma virus (ASV)-induced gliomas and that were treated optimally with radiotherapy. Toxicity of MPA (dose range of 0.2-5.0 mg/kg X 7 over 3 weeks) was first established in non-tumor bearing rats as assessed by their relative failure to gain weight. Doses of 2.0 or 5.0 mg/kg X 7 caused animals to be 21.8 or 43.9%, respectively, underweight compared with vehicle controls. In rats bearing ASV-induced gliomas, treatment with 3,000 cGY (nine fractions over a 3-week period) alone or with 0.2 or 1.0 mg MPA/kg (X 6 during the 3-week radiotherapy course) produced a significantly prolonged survival compared with that of untreated, tumor bearing rats. However, MPA did not enhance survival when given concurrently with radiotherapy; indeed, at the higher of these two doses, median survival of tumor-bearers was slightly less than with radiotherapy alone. This trend towards interference with the beneficial effects of radiotherapy was more pronounced with the highest dose of MPA studied, 5.0 mg/kg body weight X 6. These animals had a median survival time that was significantly less than that of tumor-bearers receiving radiotherapy alone, but not significantly different from untreated rats with gliomas. The possible significance of these observations is discussed.
mesh_terms: D000818:Animals; D001717:Birds; D001932:Brain Neoplasms / Q000532:radiotherapy / Q000628:therapy*; D003131:Combined Modality Therapy; D005910:Glioma / Q000532:radiotherapy / Q000628:therapy*; D006801:Humans; D008775:Methylprednisolone / Q000627:therapeutic use*; D051381:Rats; D011916:Rats, Inbred F344; D001357:Sarcoma, Avian / Q000628:therapy
chemical_list: D008775:Methylprednisolone