I have only heard vague referneces to the human experimentation that was done during that time. I also heard that the nazis enaged in this as well. There is a very dark side to human beings it seems.
The reason it was hush, hush after WW2 was that the USA wanted the findings of these scientific experiments — so deals were made that if the scientists gave the US their journals, they would be given full immunity. The ones who were caught by Russian forces did not fare as well though (the Russians did not take kindly to their POWs and women inhabitants of Harbin, China being experimented on). There is no solid evidence but is highly likely that US POWs were also experimented on — of course, once you went in you never came out.
Google “Unit 731” and you will find some really interesting historical ducumentaries on the subject. If you can stand it, watch Philosophy of a Knife — sad part is, anything they depict in that movie seems to actually be based on the real place. Tens of thousands of people met their end there and if it had not been for the atomic bomb, the biological agents they developed were scheduled to be dropped on coastal cities of the USA in early autumn of 1945. Millions would have died in the US had this occured.