PURWONINGSIH, EMNI, Doctoral Program in Biomedical Science Faculty of Medicine University of Indonesia. Jl. Salemba Raya no. 6, Kenari, Kec. Senen, Jakarta Pusat, DKI Jakarta, Indonesia 10430, Faculty of Medicine, Universitas Muhammadiyah Sumatera Utara. Jl. Gedung Arca no.53, North Sumatera 20217, Indonesia