Medstone International Inc. reported first-quarter net income...

Medstone International Inc. reported first-quarter net income of $359,000, a 57% drop from the $833,000 profit for the same period a year earlier. However, revenue was up to $4.2 million from $2.8 million. The Irvine-based company said its first-quarter performance in 1989 was significantly below 1988 results partly because its first-quarter profit last year included $350,000 in tax credits. Medstone develops, manufactures and markets shock wave systems for the disintegration of kidney stones and gallstones.