WASHINGTON - The House Ethics Committee announced Monday that it had appointed a panel to investigate whether Nevada Democratic Rep. Shelley Berkley used her position to benefit her family's financial interests, giving Republicans additional fodder to question her conduct leading up to November's election for a Senate seat in a critical swing state.The Nevada Republican Party filed a complaint last year saying that Berkley's efforts to keep a kidney transplant program open at University Medical Center in Las Vegas constituted a conflict of interest because her husband, Dr. Larry Lehrner, is a managing partner of a company that contracted with …