By TIM JOHNSON | McClatchy Newspapers Truthout Posted by Bulatlat.com MEXICO CITY — Exposing a dark page in its history, the U.S. government acknowledged Friday that government scientists had infected some 1,500 Guatemalans with syphilis and gonorrhea in experiments from 1946 to 1948 in “appalling violations” of medical ethics. U.S. scientists infected prostitutes with syphilis…