Ken Alltucker, Arizona Republic, June 28, 2007 Tracy Chavez has some advice for those who plan to check out the documentary Sicko. Bring an open mind and a box of tissue. The Arizona nurse is one of dozens of Valley health care workers who plan to use the film's release today to bring attention to the state of the nation's health care industry. "Those who have never had any health issues, they really have no clue how bad our health system can be," said Chavez, who has been a nurse at St. Joseph's Medical Center for 23 years. "Those who have never been exposed to the system will be appalled by what they see." ... Health