The Sensex at the Bombay Stock Exchange rose 89 points, or 0.5 per cent, to 17,658 in opening trade, this morning, on continued buying by investors, tracking a firm trend on the other Asian bourses. But later, the Sensex surrendered all its early gains, to briefly slip into negative territory, before recovering to stand just 4 points in the positive zone, at 17,573, in volatile trade, a short while ago.Key stock indices in Japan, China, Hong Kong, Singapore and South Korea were between 0.2 percent and 2 percent higher, today.Across in the US, the Dow Jones Industrial Average had gained 0.8 per cent, overnight, on hopes that Italy would proceed with reforms to prevent the Euro-zone's sovereign debt crisis from spreading.