A) Boxplot representation of C
and DSB levels in the control (C) and diabetic (D) cohort. Whereas C16SA, C16SO, C18SA and C18SO were not different between the two groups were doxSA and doxSO levels higher in the diabetic group. (Box represents the upper and lower quartile, whiskers show the 5% and 95% percentile, the horizontal line represents the median) C) Receiver operator curve (ROC) for doxSO D) Area under the curve (AUC) and p-values for all analyzed variables were calculated from a ROC analysis. Most significant parameters are marked (p values were calculated with the null hypothesis (H0) as AUC = 0.5). E) Distribution of the DSB and C16 sphingoid bases in the distinct lipoprotein fractions. Human plasma was separated by a four step density gradient ultracentrifugation. The individual fractions were assayed for cholesterol (not shown), triglycerides (TG; dashed line), doxSA (triangle) doxSO (triangle) and C16SO. Both doxSA and doxSO are only found in the VLDL and LDL but not in the HDL lipoprotein fraction. C16-SO, in contrast, was present in LDL and HDL but not in VLDL. The sum of all fractions was defined as 100% and values are given as a percentage of the total.