As chief executive of Vanderbilt University Medical Center, Harry Jacobson, MD, likes President-elect Obama's pledge to expand health insurance coverage. For hospitals and doctors, coverage for the more than 46 million Americans who now lack insurance could mean more people can pay their bills. At Vanderbilt, that could help lessen the financial wallop of providing $245 million worth of care to people unable or unwilling to pay last fiscal year. In Nashville's signature healthcare industry, Democratic control of the White House and both houses of Congress has raised hopes among some medical providers. But other sectors might not fare so well under Obama's administration, experts say.