Stocks Slightly Ahead, Lower Oil Helps  NEW YORK (Reuters) - U.S. stocks were slightly higher on  Tuesday, with lower oil prices helping support markets, but  Johnson   Johnson &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=JNJ.N target=/stocks/quickinfo/fullquote"&gt;JNJ.N&lt;/A&gt; dragged on the Dow following a report  of a possible \$24 billion takeover of cardiovascular device  maker Guidant Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=GDT.N target=/stocks/quickinfo/fullquote"&gt;GDT.N&lt;/A&gt;.