Erasing initial gains, the Sensex at the Bombay Stock Exchange was trading 64 points in the negative territory at 17,498 when reports last came in. The 30-share index gained nearly 70 points in early trade today or 0.39 per cent, to 17,632.Buying in capital goods, refineries, power, auto and metal stocks helped the Sensex gain.In a similar fashion, the wide-based National Stock Exchange Nifty Index was trading 17 points in the red at 5,268.In the Asian region, Hong Kong's Hang Seng index rose by 0.73 per cent. The US Dow Jones Industrial Average ended 0.71 per cent higher yesterday.