Submitted on: 06 March 1999.
Revised on: 14 April 1999.
Accepted on: 03 June 1999.
___________________BRITISH JOURNAL OF HOSPITAL MEDICINE
Submitted on: 13 August 2004.
Revised on: 16 November 2004.
Accepted on: 03 December 2004.
___________________BRITISH JOURNAL OF HOSPITAL MEDICINE
http://reply.papertrans.cn/1/43/4212/4212-33.png
http://reply.papertrans.cn/1/43/4212/4212-34.png
http://reply.papertrans.cn/1/43/4212/4212-35.png
http://reply.papertrans.cn/1/43/4212/4212-36.png