Sungjin Chung1
, Cheol Whee Park2
, Hyun Wha Chung3
, Seok Joon Shin3
and Yoon Sik Chang1 
1
Division of Nephrology, St. Mary's Hospital, The Catholic University of Korea, 62 Yeouido-dong, Yeongdeungpo-gu, Seoul 150-713, Republic of Korea
2
Division of Nephrology, Seoul St. Mary's Hospital, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-040, Republic of Korea
3
Division of Nephrology, Incheon St. Mary's Hospital, The Catholic University of Korea, 665-8 Bupyeong 6-dong, Bupyeong-gu, Incheon 403-720, Republic of Korea