... and after clamping of the carotid artery. Principal component analysis (PCA) as well as partial least square regression analysis (PLS) was applied to interpret the data. Results: PCA and PLS analysis ... Fujisawa H, Akimura T, Ishihara H, Kajiwara K, Kato S, Fujii M, Yamashita S, Maekawa T, Suzuki M. Increased ma-trix metalloproteinase-9 in blood in association with activation of interleukin-6 after ... combination of vari-ables, capturing a maximum of the variance remaining in the data set, and is orthogonal to all other compo-nents. In biological material, with a considerable de-gree of collinearity...