KRIS-TV (NBC) Ch. 6 Corpus Christi (Internet / TV) 06/17/06 A group of area doctors, medical students and volunteers gave up their Saturday to help those living in Nueces County colonias.  They gave free checkups at Saint Vivian's Catholic Church in Petronila.  For some this was the first checkup in years. Getting a free check up did not take much effort. For the medical students, the health fair is a two way street. "It's mutually beneficial, they get the free care and consultation, and we really appreciate them letting us ask questions," said Rachel Giese of the San Antonio-based chapter of Frontera de Salud, a program that was founded by the University of Texas Medical Branch’s Dr. Kirk Smith.