Health-care communications technology company Synetic Inc. said it will buy Medical Manager Corp., a medical practice management software company, in a stock deal valued at about $1.3 billion. The combined entity would be called Medical Manager. The deal would give Elmwood Park, N.J.-based Synetic a boost in the race to link the nation's doctors and their desktop computers with health plans, clinical labs, pharmacy benefit managers and other health-care players in an online network. Under the agreement, each outstanding share of Medical Manager common stock would be exchanged for 0.62 newly issued share of Synetic common stock, subject to a price protection mechanism. The proposed merger values stock in Tampa, Fla.-based Medical Manager at about $55 a share, a large premium over its Friday closing price of $33.75. Medical Manager stock jumped $14 to close at $47.75, while Synetic stock closed at $91, down $4.50. Both trade on Nasdaq.