By Lester Holt, NBC News anchor

Some new fuel has been added to the fire of the health care debate. Today, lawmakers were not only reacting to last night's Senate vote to begin consideration of a health care reform bill, they were also sounding off on the government's controversial new recommendations for breast cancer screening.

Republicans are quickly making those suggested mammogram guidelines central to their opposition to the Democratic health care plans, saying they could result in limits on mammograms and a rationing of care. We'll hear some of those voices on tonight's broadcast and report on the difficult days ahead for Democrats as they try and find unity on a health care reform bill.

If you're staying home for Thanksgiving this year, NBC's Tom Costello will explain why you'll have plenty of company this year. Tom is looking at the holiday travel picture for us tonight.

Jeff Corwin will preview his fascinating msnbc documentary "100 Heartbeats," on animals facing the threat of extinction.

We will also tell you about a U.S. astronaut who is over the moon about some news he got last night from back here on Earth.

I hope you can join us later for NBC Nightly News.