From the 1970s through the 1980s, advances were made in medical technology that enabled the enzyme to penetrate into cells. However, because each type of cell had its own specific "key" for allowing entry, only liver and spleen cells could be effectively penetrated, while the main therapeutic targets--muscle and heart tissue cells--remained impervious.
1970 到 80 年代，醫療技術有了進展，已能將酵素送進細胞，但因每一種細胞各有「開門密碼」，而當時的酵素只能穿透進入肝臟和脾臟細胞，卻始終無法進到主要的治療目標──肌肉和心臟細胞。