Table 1. Supernatant hTK levels of cells culture (mean±S).

Cells	2 days	4 days	6 days	8 days	10 days	14 days
Ad/hTK	1322.12±37*+	6297.28±142*+	9137.48±134*+	1724.98±141*+	734.19±26*+	314.18*+
Ad/GFP	52.33±12§	48.13±9§	50.81±10§	53.36±9§	48.08±8§	49.47±10§
EPCs	47.91±9	47.90±8	51.87±10	46.08±8	52.58±11	54.48±12

^*P<0.01 compared with Ad/GFP+P<0.01 compared with EPCs.

^§P>0.05 compared with EPCs.