Transoma Medical Inc., a St. Paul, Minn.-based maker of implantable wireless vital sign monitors, has filed for a $75 million IPO. It plans to trade on the Nasdaq under ticker symbol TSMA, with Piper Jaffray and Thomas Weisel Partners serving as co-lead underwriters. Transoma has raised just over $38 million in total VC funding, from firms like Polaris Venture Partners (24.53% pre-IPO stake), Canaan Partners (20.05%), Affinity Capital Management and Cross Creek Capital.