title: Type C oncornavirus isolation studies in systemic lupus erythematosus. I. Attempted detection by isopycnic sedimentation of 3H-uridine-labelled virions.
abstract: Type C oncornavirus isolation was attempted from cell cultures of tissues from 7 patients with systemic lupus erythematosus. Detection was based on the characteristic sedimentation of 3H-uridine-labelled virions at a density of 1-16 g/ml. Cultures positive by this method were negative by two other criteria for type C viruses: characteristic virions by electron microscopy and the viral enzyme RNA-directed DNA polymerase. The positive results were probably due to cellular damage by prolonged radiolabelling, with release of organelles containing labelled RNA sedimenting at the same density as type C viruses.
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000382:microbiology*; D008854:Microscopy, Electron; D009858:Oncogenic Viruses / Q000201:enzymology / Q000302:isolation & purification*; D012194:RNA-Directed DNA Polymerase / Q000032:analysis; D014461:Ultracentrifugation; D014779:Virus Replication
chemical_list: D012194:RNA-Directed DNA Polymerase