“Thermostable” Thromboplastin from Human Placenta and Chicken Brain. ∗

Abstract

Summary

A method of preparation of thermost able thromboplastin from human placenta and of thermolabile but reactivable thromboplastin from chicken brain is described. The properties and differences of these preparations are discussed. Human placenta thromboplastin is not inactivated by heating at 98°C for 5 minutes. Chicken brain thromboplastin is inactivated by the heat treatment but is subsequently reactivated when it is stored at 44°C. The different activities of heated and unheated placenta and chicken brain thromboplastin on stored oxalated human plasma and native chicken plasma are explained by the assumption that thromboplastin is composed of two factors, one of them thermostable and the second thermolabile. Clinical, surgical, and research applications of thermostable preparations of thromboplastin are discussed.