Influence of sialic acid on neonatal fibrin network properties. (A) Sialic acid concentration of neonatal fibrinogen is significantly greater than adult fibrinogen. N = 3 triplicate experiments. (B) Representative images of confocal microscopy analysis of clots taken at 63× magnification. Before removal of sialic acid, fiber density was statistically significant between adults and neonates; after removal, resulting clot structures were roughly equivalent in fiber density. N = 5 clots per group. Scale, 10 μm. (C) Polymerization curves were analyzed via turbidity measurements on a plate reader. (D) Maximum turbidity values were significantly lower in neonates compared with adults before removal of sialic acid and similar after. N = 5. (E) Normal neonatal fibrinogen had significantly lower clottability than adult fibrinogen; after digestion of sialic acid, clottability was similar. N = 4. (F) Fibrinolysis was initiated with plasminogen and tissue plasminogen activator. Normal neonatal fibrinogen had statistically faster degradation rates than adult fibrinogen. After removal of sialic acid, degradation rates were similar. N = 3. Average ± standard deviation is shown. *P < .05.