Biotech company Artegraft is accusing renowned attorney James Tyrrell and his former firm, Latham & Watkins, of malpractice that cost the company more than $10 million. Artegraft claims Tyrrell and the firm convinced it to sue Johnson & Johnson in a contract dispute based on a legally unfounded patent theory. Latham says Artegraft was a savvy client that was aware of the risks and is now trying to avoid paying $1.6 million in bills. The litigation comes as Tyrrell leads a 30-lawyer exodus to Patton & Boggs.