Culture medium contained DMEM containing
4.5 g/l with L-glutamine, without sodium pyruvate (Life Technologies,
Paisley, UK) and supplemented with 10% foetal bovine
serum, 100 U/ml penicillin, 100 mg/l streptomycin and geneticin
– G418, 400 lg/ml purchased from Sigma (Dorset, UK).