The Milan Stock Exchange closed sharply lower Thursday due to uncertainty surrounding the conflict in the Middle East, and the FTSE MIB index fell 1.61% to 44,608 points.     Nexi (-16.6%) was the worst performer, with analysts disappointed by the plan and the lack of a buyback. Amplifon (-13.2%) also came under pressure after the results were released.     Campari, however, surged (+9.96%), followed by ST (+2.99%) and Snam (+1.57%).     Wall Street is trading in negative territory, driven by