Louisville-based insurer Humana, Incorporated has announced plans to purchase a Texas-based health care company.Spokesperson Jim Turner says pending regulatory approval, Humana will buy Concentra, Incorporated for about $790 million in cash."Concentra is a strong company, it fits very will with Humana's focus on working directly with our individual members. Already, approximately three million humana members live very close to a Concentra center. We view that as a big plus, he said. Concentra operates more than 300 medical centers in 42 states, offering services such as urgent care, physical therapy and occupational medicine. It also has more than 240 worksite facilites.The purchase could be completed by the end of the year.