Mexican glassmaker, Vitro, reported a weak first quarter with declining revenues as expected, but inustry analysts found a silvler lining in the firm's operating margins, which, though lower, performed better than expected. Vitro, based in the north eastern city of Monterrey, specializes in flat glass and glass containers, but also runs divisions manufacturing glassware, white goods and diverse products, including lab equipment and electronic parts. The firm releast its first-quarter results, which are analysed in inflation-adjusted terms. Overall sales fell 2.78% from the first quarter of 1998 to Pso5.801bn (US$624m), mostly due to a slowdown in the Mexican economy. Operating profit of Pso999.54m slightly topped expectations of Pso996m. Lower sales & higher-than-expected operating income resulted in a consolidated operating margin of 17.2%, (17.9%).