Complex sentence: He immigrated with his family to the United States in 1979, and upon completing his internal medicine residency program, he began a fellowship in endocrinology and metabolism at Boston's Beth Israel Hospital (now Beth Israel/Deaconess Medical Center).
Split into simpler sentences: He immigrated with his family to the United States in 1979. Upon completing his internal medicine residency program, he began a fellowship in endocrinology and metabolism at Boston's Beth Israel Hospital (now Beth Israel/Deaconess Medical Center).