A federal judge Tuesday stayed the antitrust case filed by West Penn Allegheny Health Systems against UPMC, saying in a sharply worded order that West Penn has accused him of being biased. U.S. District Judge Arthur J. Schwab today wrote in an order that his court cannot "properly function under such a threat" of accusations of bias by one of the parties in the highly publicized case. He was referring to a footnote in a motion filed by West Penn Allegheny on Friday, in which attorneys for the region's second-largest hospital system wrote that he "has made a worrisome practice of misstating and mischaracterizing" their positions in the case.