| 摘要 |
A lyophilized reagent for testing the coagulability of blood comprises a blood platelet factor substitute and finely divided discrete inert particles. The blood platelet factor substitute may be an extract of rabbit's brain and the particles may be of kaolin, powdered glass, sand, bentonite or diatomaceous earth and have a size of 2-20 microns. In addition suspending agents (calcium-free acacia, tragacant or guar gum) may be present. In an example, rabbit's brains were ground with acetone whereby the tissues were broken up, dried and rendered cholesterol free, and then extracted with chloroform. The extract was evaporated and reconstituted with isotonic aq. NaCl. Diatomaceous earth was added together with sodium barbital and NaCl and the pH adjusted to 7.5 with 10% aq. HCl. The product was filled into ampoules and lyophitized. In use, the reagent is added, with a CaCl2 solution to blood plasma and the clotting time noted, under standard conditions. The particles serve to activate uniformly one of the plasma factors (Hageman factor) affecting clotting time. |
