Giving up all its initial gains, the Sensex at the Bombay Stock Exchange slipped 75 points or 0.4 percent into the red, at 19,516 in afternoon deals, a short while ago, amid sustained profit-booking by investors, in volatile trading. In the morning, however, the Sensex had gained 83 points, to 19,674, on the back of selective buying by funds and retail investors, amid firm regional bourses. The Sensex has lost more than 110 points in the last three trading sessions, after the big run-up, recently. Other Asian markets in Japan, China, Hong Kong, Indonesia and Singapore rose between 0.1 percent and 1.5 percent, today. The US Dow Jones Industrial Average had slipped 0.1 per cent, overnight.