A presidential panel on Monday disclosed shocking new details of U.S. medical experiments done in Guatemala in the 1940s, including a decision to re-infect a dying woman in a syphilis study. The Guatemala experiments are already considered one of the darker episodes of medical research in U.S. history, but panel members say the new information indicates that the researchers were unusually unethical, even when placed into the historical context of a different era. "The researchers put their own medical advancement first and human decency a far second," said Anita Allen, a member of the Presidential Commission for the Study of…