MOSCOW (AP) — A 35-year-old Russian celebrity TV host who wants to become a presidential candidate has opened her first news conference by demanding the release of all political prisoners. Ksenia Sobchak announced her presidential bid last week, arguing that Russia has grown tired of its current political elite. Critics said Sobchak's run would further fragment the opposition while lending the March election a veneer of legitimacy. Sobchak, the daughter of President Vladimir Putin's mentor, former St.