Updating a story from earlier today, a southern Illinois prison is on lockdown after a weekend altercation left four guards with slight injuries.  The Illinois Department of Corrections says the fracas at the medium-security Pinckneyville Correctional Center for men began about 10 AM yesterday when a guard asked an unruly inmate to step out of the meal line.  That’s when another inmate apparently punched the guard.  After three other correctional officers responded, a third inmate joined in the altercation before guards used pepper spray to subdue the prisoners involved.  Three of the guards were treated at a hospital, including one officer who sustained a broken nose.  The fourth guard and the accused inmates were treated at the prison’s health-care unit.  Corrections officials say charges will be pursued.  The lockdown restricts inmate movement and bars visitation.