Pak, Yong Guk, Pyongyang University of Medical Sciences Pak, Yong-Chol, Medical Biology Institute, Academy of Medical Science, Pyongyang, Democratic People’s Republic of Korea. Pak, Yun-Hui, Pyongyang Maternity Hospital, Pyongyang, Democratic People’s Republic of Korea. Pratama Umar, Tungki , Faculty of Medicine, Sriwijaya University, Palembang Pyon, Sun Gum , Department of General Internal Medicine. Hospital of Pyongyang University of Medical Sciences, Pyongyang, Democratic People’s Republic of Korea.