The stock market remained lower in afternoon trading Tuesday, although the indexes came off their session lows. The Nasdaq led the way down with a 0.6% drop. The S&P 500 was down 0.2% and the Dow Jones industrial average 0.1%. The small-cap Russell 2000 gave up 0.4%. Volume tracked slightly higher than at the same time Monday. Biotechs and other medical stocks tumbled — one of the reasons why the Nasdaq lagged.