Fig. 4.

Lipid 430/Lipid 654 ratios for carotid endarterectomies, normal carotid artery samples, human brain samples, bacteria lipid extracts, and serum from healthy subjects. Lipid samples were extracted as described in the Materials and Methods and were analyzed using ESI-MRM. Lipid 430 and Lipid 654 were quantified using ESI-MRM and ratios were calculated from electronically integrated peaks. The results are depicted as Box plots and show the median ratios of Lipid 430/Lipid 654 for each category of samples (n = number of samples). Kruskal-Wallis ANOVA revealed significant differences between sample medians (P = 2.199 × 10⁻⁸). The median Lipid 430/Lipid 654 ratio for carotid endarterectomy lipid extracts (#) was significantly elevated over the median ratio in bacterial samples (P = 4.83 × 10⁻⁶), brain samples (P = 0.00021), control arteries (P = 0.00145), and serum samples (P = 0.00005) by Mann-Whitney U test.