title: The significance of 3H-thymidine degradation in cell culture experiments with special reference to rheumatoid arthritis.
abstract: The degradation of 3H-thymidine under various cell culture conditions was analysed. It was found that a half of 3H-thymidine was degraded to 3H-thymine during 24 hours in PHA stimulation of blood lymphocytes. A control culture in which PHA was not added also caused 3H-thymidine degradation. 3H-thymidine degradation was prevented by adding 5-nitrouracil to the incubation medium at a concentration of 0.577 mg/ml. At the same time 5-NU increased 3H-thymidine incorporation into lymphocytes by 47%. 5-NU also eliminated the inhibitory effect of rheumatoid arthritis synovial tissue eluate on PHA stimulation. In addition 5-NU and nonradioactive thymine increased the 3H-thymidine labelling index of fresh rheumatoid arthritis synovial membrane biopsies, and also more of the isotope was accumulated in the individual cells of the membrane. These studies demonstrate that 3H-thymidine degradation is an important phenomenon in cell cultures and that it can be prevented effectively by using 5-nitrouracil with 3H-thymidine.
authors.affiliation: Fourth Department of Medicine, Helsinki University Central Hospital, Finland.
authors.forename: P J
authors.initials: PJ
authors.lastname: Nykänen
authors.forename: P V
authors.initials: PV
authors.lastname: Raunio
authors.forename: P U
authors.initials: PU
authors.lastname: Kankaanpää
mesh_terms: D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism*; D013939:Thymidine Phosphorylase / Q000037:antagonists & inhibitors; D013941:Thymine / Q000378:metabolism; D014498:Uracil / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D010835:Phytohemagglutinins; D014498:Uracil; C057449:5-nitrouracil; D013939:Thymidine Phosphorylase; D013941:Thymine; D013936:Thymidine