The basic federal rules for protecting the human subjects of research studies are sound and do not need major changes, according to a report  issued by the Presidential Commission for the Study of Bioethical Issues. The commission was charged by President Obama with reviewing those rules in the wake of reports about research supported by the U.S. Public Health Service in Guatemala from 1946 to 1948 that intentionally exposed thousands of Guatemalans to sexually transmitted diseases without their consent. "The commission is confident that what happened in Guatemala in the 1940s could not happen today," said a statement from Amy Gutmann, chair of the commission and president of the University of Pennsylvania. While the basic system works, the commission said, some changes could improve it. The panel called for more data to be collected about studies with human subjects. And the commission suggested studying systems for compensating those injured in studies.