When Sister Mary Jean Ryan entered the convent as a young nurse in 1960, virtually every department of every Catholic hospital was run by a nun, from pediatrics to dietary to billing. After her retirement on July 31 as the CEO of one of the country's largest networks of Catholic hospitals, only 11 nuns remained among her company's more than 22,000 employees, and none were administrators. For SSM Health Care, a $4.2 billion enterprise that evolved from the work of five German nuns who arrived here in 1872, Sister Mary Jean's departure after 25 years as the company's first chief executive marks a poignant passing. The gradual transition from religious to lay leadership, which has been changing the face of Catholic health care for decades, is now nearly complete. In 1968, nuns or priests served as CEO of 770 of the country's 796 Catholic hospitals, according to the Catholic Health Association. Today, they preside over 8 of 636 hospitals. With Sister Mary Jean's departure, only 8 of 59 Catholic health care systems are directed by religious executives. The leadership shift has stirred angst in many Catholic hospitals about whether the values imparted by the nuns, concerning the treatment of both patients and employees, can withstand bottom-line forces without their day-to-day vigilance.