JOHNSON CITY, Tenn. – Dr. Matthew Loos has been named vice president/chief medical officer for Mountain States Health Alliance’s Washington County (Tenn.) Market. ... read more about Dr. Matthew Loos named VP/chief medical officer for Mountain States’ Washington County (Tenn.) hospitals. JOHNSON CITY, Tenn. – Dr. Matthew Loos has been named vice president/chief medical officer for Mountain States Health Alliance’s Washington County (Tenn.) Market. ...