HMO AMERICA <HMOA> AGREES TO BE ACQUIRED HMO America Inc said it signed a letter of intent with Mount Sinai Medical Center here and an affiliate, providing that all of its common and preferred stock be acquired by a new not-for-profit company to be controlled by Mount Sinai and other Chicago area not-for-profit hospitals who may elect to participate in the acquisition. The form of the transaction has not yet been determined, it said. According to terms, HMO's shareholders would receive a combination of cash and debt securities to be issued by the buyer in exchange for their outstanding shares of common and preferred stock, it said. The amount of cash per share has not yet been determined, it added. Arrangements for financing have not yet been made and there can be no assurance that any financing will be received, HMO said. Closing of the proposed transaction, if it is completed, is expected on or before November 2, 1987, it said.