The blood PLTs were fixed with 1.5 % glutaraldehyde and 1 % PFA in 0. Samples were embedded in silicone mold with resin and polymerized at 60° C for 72 hours. 70 nm ultrathin sections were cut with an Ultracut ultramicrotome (UCT, Leica microsystems), deposited on 150 mesh copper grids, and contrasted with 2.5 % uranyl acetate and 2 % lead citrate. Observations were performed using a LaB6 JEM 2100 HC TEM (Jeol) at 80 kV.