Human aortic endothelial cells ( HAECs ) were stimulated by angiotensin II ( Ang II , 100 nmol/L ) with or without pretreatment of valsartan ( 100 nmol/L ) , and relative expression of cyclooxygenase-2 ( COX-2 ) and thromboxane B 2 ( TXB 2 ) and both p38 mitogen-activated protein kinase ( p38MAPK ) and nuclear factor-kB ( NF-kB ) activities were assessed .