Fig. 4. Effect of thiamine on (a) 3-deoxyglucosone concentration, (b) transketolase activity, and (c) pentosephosphate metabolites in human red blood cell suspensions in vitro. Key: N, + 5 mM glucose; H, + 50 mM glucose; N + T, + 5 mM glucose and 500 mM thiamine; and H + T, + 50 mM glucose and 500 mM thiamine; and a. N + TPP, + 5 mM glucose incubation with 350 mM TPP added to diluted lysate; H + TPP, + 50 mM glucose incubation with 350 mM TPP added to diluted lysate; and b. bar filling key: u xylulose-5-phosphate, ??? ribulose-5-phosphate, and solid square combined sedoheptulose-7-phosphate and R-5-P. Significance: a. ^**p < 0.01 and ^***p < 0.001, with respect to t = 0; ^oop < 0.01 with respect to N. b. and c. ^*p < 0.05, ^**p < 0.01, with respect to non-thiamine supplemented control. N. Data are mean SD of 3-6 determinations.