Complex sentence: Entering the United States Army as a regular, in 1983, he graduated with a Medical Doctorate from the Uniformed Services University of the Health Sciences School of Medicine, and was commissioned a Captain in the Medical Corps.
Split into simpler sentences: Entering the United States Army as a regular, he was admitted to medical school. In 1983, he graduated with a Medical Doctorate from the Uniformed Services University of the Health Sciences School of Medicine, and was commissioned a Captain in the United States Army Medical Corps.