 The White House briefing gets testy. I'm Lisa Lucera, Fox News. As the White House press secretary beats back questions about the president's fitness to serve a second term. In an often contentious exchange with reporters, Press Secretary Karine Jean-Pierre would not explain why a Parkinson's expert visited the White House several times over the past year. There are thousands of military personnel that come to the White House and they are under the care of the medical unit. Jean-Pierre says the president has