Ronald J. Ryan resigned as president of Ryan Labs, the firm he founded in 1988, and was replaced by Sean F. McShea, COO, according to Mr. McShea. Mr. Ryan put in a bid to acquire full control of the company Thursday and when shareholders declined, he submitted his resignation, according to Mr. McShea. The firm's board of directors was determining how to acquire the rest of Mr. Ryan's stake in the company, which Mr. McShea said was "substantial" but less than a majority. The board offered Mr. Ryan a position on the firm's advisory board, and they are negotiating, Mr. McShea said. No other senior staff members had left the firm and Mr. McShea was in the process of speaking with all Ryan Labs' clients. Efforts to reach Mr. Ryan were not successful.