The widow of murdered UCSD researcher Tsunao Saito has filed another round of libel suits against Japanese publications she says defamed her by running false reports suggesting she might have had a role in her husband's death. Shizue Saito is seeking more than 10 million yen from Kyodo News Service and the Naigai Times newspaper and 6.6 million yen from Nihon Keizai Shinbun. Her husband Tsunao, a 46-year-old expert in Alzheimer's disease, was gunned down along with the couple's 13-year-old daughter Ruri as they returned to their La Jolla home late one night in May 1996. San Diego police have been unable to solve the case ... Irate Houstonians are joining forces to protest the decommissioning of the San Diego-based nuclear submarine, USS Houston. The Navy wants to take the 16-year-old vessel out of service in January 2001 and cut it up for scrap. But the ship's captain, Commander Michael A. Zieser, along with Houston's Navy League, is waging a campaign in the Houston media to save the ship, reports the Houston Chronicle. Latest line of attack: a daylong cruise on the sub for 25 backers from Houston and a contingent of fawning reporters.