tokens: RESULTS : Induction of NF-kappaB DNA binding by the p65 ( RelA ) /p50 heterodimer was observed in response to incubation of Mono Mac 6 cells with SF ( 20 % in culture medium ) from 5 of 8 subjects with RA , 4 of 5 with OA , and none of 3 with undifferentiated seronegative oligoarthritis .