Britain's Princess Diana says she needs a miracle cure to stop her from biting her nails. "I have tried everything to stop," she told manicurist Ros Scott during a visit to an Oxford hospital. "It is a nervous habit. Have you got a miracle cure?" Advised to try putting something bitter on her nails, Diana, 23, reportedly replied: "I think I'm too old to stop now" . . .

20th Century-Fox and the city fire department plan to give the movie "Turk 182!", starring Timothy Hutton, a boost Sunday morning. Pennsylvania Avenue between 13th and 14th streets is scheduled to be closed at 8:30 a.m. so that TURK 182 can be written in red chalk on the pavement. The letters will be 12 feet tall and decorated with fire equipment. The movie details the difficulties a man has in getting recognition for his brother, a firefighter who dies while saving another's life . . .

The New York Post reports that First Daughter Patti Davis is working on her first novel. The publisher is Crown and the advance is in six figures. One of the main characters is said to be a man who moves from the governor's mansion in California to the White House.