“…Its advantages, compared with other nonviral gene delivery systems, are that gene expression is drastically increased (2-to 4-log fold), longlasting (months), and very specific and localized . This technique has also been successful in various tissues such as skeletal muscle (Muramatsu et al, 1998;Aihara and Miyazaki, 1999;Gehl and Mir, 1999;Imai and Isaka, 1999;Mathiesen, 1999;Rizzuto et al, 1999;Bettan et al, 2000;Lemieux et al, 2000;Maruyama et al, 2000;Vicat et al, 2000;Lucas and Heller, 2001;Muramatsu et al, 2001), liver (Suzuki et al, 1998;Heller et al, 2000), testis (Muramatsu et al, 1997;Yamazaki et al, 1998;Yamazaki et al, 2000), skin (Johnson et al, 1998;Vanbever and Preat, 1999;Glasspool-Malone et al, 2000), cornea (Oshima et al, 1998;Sakamoto et al, 1999), cardiaovascular (Harrison et al, 1998;Martin et al, 2000) and mammary tumor tissue Wells et al, 2000;Lohr et al, 2001). In particular, gene delivery to skeletal muscle is a promising strategy for the systemic secretion of therapeutic proteins.…”