OSAKA -- Sisters of a female patient who died under suspicious circumstances at Osaka Ensei Hospital in Higashi Sumiyoshi Ward here filed a lawsuit May 14 with the Osaka District Court against the hospital's medical corporation, seeking 11 million yen in damages.

The woman was admitted to Yamatogawa Hospital, a mental institution in Kashiwara, Osaka Prefecture, in April 1994. According to the plaintiffs, who requested anonymity, she appeared to be improving after two months of care at the hospital.

However, she contracted a fever and started running a temperature of more than 40 degrees. She was transferred to Osaka Ensei Hospital on July 6, 1994, and died the same day.