Serum levels of cortisol , adrenocorticotropic hormone ( ACTH ) , endothelin-@ ( ET-@ ) , tumor necrosis factor - ( TNF - ) , interleukin-@ ( IL-@ ) and C-reactive protein ( CRP ) were measured by standard ELISA and radioimmunoassay before anesthesia ( Ta ) , at the end of the surgery ( Tb ) and @ day after the surgery ( Tc ) .