1. Department of Molecular Biology and Biotechnology, Nigerian Institute of Medical Research, Yaba, Lagos 100001, Nigeria
2. Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Idaigaoka, Hasama-machi, Yufu 879-5593, Japan
3. Department of Medicine-Gastroenterology and Hepatology Section, Baylor College of Medicine, Houston, TX 77030, USA