Stocks on the Greek bourse could not sustain the gains they had posted during Wednesday’s trading, as blue chips and the main index closed the session with slight losses. The Athens Exchange (ATHEX) general index dropped to 1,578.63 points yesterday, sliding by 0.35 percent from Tuesday’s close. During the day it had shown a rise of 1.27 percent. The blue chip FTSE/ATHEX 20 index fell by 0.50 percent to close at 778.28 points. However, both the mid- and small-cap indices recorded slight gains. Outperforming among blue chips were the stocks of Titan cement (up 2.66 percent), Intralot (2.06 percent) and Coca-Cola Hellenic (1.18 percent). The worst losses were for the blue chips of Marfin Investment Group (down 4.84 percent) and Alpha Bank (1.74 percent). Turnover reached 93.9 million euros.