Fig. 5.

Effects of nitrite and far red light on clotting. Platelet poor plasma containing fibrinogen and an activation solution containing thrombin were prepared separately and, in some cases, incubated with deoxygenated RBCs (20% Hct), nitrite (10 μM), and/or treated with far red light (660 nm, 10 min, 107 mW). All experiments were performed pair-wise; that is two types of samples were performed side by side per day and the results compared. Data are plotted as mean ± one standard error. (A) Representative plots of optical density (OD) vs time after initiation of clotting, shown here for the case of a control (CNT, RBCs but no other treatment) vs a sample administered nitrite and light treatment (Nit + Lit). Except for the nitrite and light treatment, both samples were treated identically. (B) Average lag times and standard errors for repeated measures. In the absence of RBCs, nitrite had no effect on the lag time (control (CNT) vs Nit, P = 0.78, n = 5). When mixtures were pre-incubated with RBCs, nitrite treatment resulted in prolonged lag times compared to no nitrite treatment (CNT vs NIT, *P < 0.01, n = 8). Illumination with far red light (660 nm, 10 min) along with the nitrite treatment during pre-incubation with deoxygenated RBCs also prolonged lag time compared to when the nitrite and light treatments were both absent (CNT vs Nit+ FR, *P < 0.01, n = 5). Inclusion of the illumination treatment along with the nitrite treatment prolonged lag times compared to nitrite treatment alone (Nit vs Nit +FR, *P < 0.05, n = 10).