Thousands of Guatemalans were intentionally infected with [sexually-transmitted diseases] in the 1940s by US public health researchers. An appeal on their case against the US government was dismissed this week. Thousands of Guatemalans ... were unwittingly subjected to secret human experiments led by US doctors. Nearly three years after beginning the legal battle in US courts, attorneys representing an estimated 5,000 Guatemalan victims used as guinea pigs and infected with sexually transmitted diseases in the 1940s by US public health researchers withdrew their appeal earlier this week. The alleged victims include soldiers, inmates, sex workers, mental health patients, and schoolchildren. Dr. John Cutler ... led the experiments in Guatemala from 1946 to 1948. Under a grant by the National Institute of Health, Dr. Cutler and US researchers gave antibiotic penicillin to test its ability to cure and prevent syphilis. But, his team also infected test subjects without their consent. Some 1,300 were deliberately infected with syphilis and other sexually transmitted diseases. Researchers would expose inmates to infected prostitutes brought into jails. In other cases, they would first infect patients in mental hospitals before testing the effects of the medication. The American team studied and performed experiments on more than 5,000 subjects - including orphans as young as 6 years old.