Providence Health & Services has announced that it will purchase Tarzana Regional Medical Center from Tenet Corp. The sale is expected to take two months to close. The amount of the sale was not disclosed. Tarzana’s 1,200 employees, including hospital head Dale Surowitz, are expected to remain in their capacities at the hospital, a representative said. Tarzana Regional Medical Center has been for sale for more than four years. Its former medical partner, Encino Hospital, was purchased by Victorville-based Prime Healthcare in early June.