Chicago Tribune columnist Mary Schmich, who has written “Brenda Starr” for the last quarter-century, and artist June Brigman have decided to end their association with the strip. “There’s sadness about stopping, but no regret and no ambivalence,” says Schmich. “It came to me really clearly that I was done. … I don’t think the character is dead. But the comic strip in this form is.” The last strip runs Jan. 2.