This study examines the effects of heat treatment for 72 h at 80 degrees C on the potential thrombogenicity of lyophilized human coagulation factor IX concentrates. Since heating generated minor amounts of thrombin, concentrate was prepared with antithrombin III addition prior to heat treatment. Changes in coagulation parameters were followed prior to and after infusion of 100 iu/kg of heated and unheated concentrates to dogs. All batches produced a transient fall in platelet count during infusion and a delayed rise in plasma fibrinopeptide A, accompanied by a minor prolongation of the activated partial thromboplastin time. Such changes were less marked for heated batches. Control infusion of a 'failed' factor IX concentrate showed an additional fall in fibrinogen, rise in fibrin degradation products and a more rapid rise in fibrinopeptide A, while thrombin infusion caused an even more dramatic intravascular coagulation. These studies indicated no increase in the potential thrombogenicity of freeze dried factor IX concentrates as a result of heat treatment.

SummarySamples taken at various stages of preparation of intermediate purity factor VIII concentrate were assayed for factor VIII coagulant activity (VIII:C), factor VIII coagulant antigen (VIIIC: Ag) and factor VIII related antigen (VIIIR: Ag). The antigen results were used to assess mechanical loss during fractionation as these markers are relatively stable. In contrast VIII:C is sensitive to both mechanical and inactivation losses.The major loss of factor VIII occurred during the cryoprecipitation and extraction step and was due to both mechanical loss and inactivation. Losses before and after this step were largely due to inactivation of the factor VIII.Assay of VIIIR: Ag in concentrates presented problems and a modified technique is suggested.

Cryoprecipitation is commonly used as the primary step in the preparation of clinical factor VIII concentrates; yet recovery is usually very low. Much of this loss is due to poor temperature control and a process of continuous plasma thawing has been designed to overcome this. A substantial improvement has resulted, with an increase in both yield and purity of factor VIII:C of over 50% in comparison to a conventional batch thaw process.

The use of unprocessed bone carries a risk of transmission of blood borne diseases. Although models of infectivity are unproven, a theoretical risk of transmission of variant Creutzfeld-Jakob Disease, a human prion disease, exists as probable blood borne transmission has been reported in three cases. The aim of our study was to determine the effectiveness of standard operating theatre pulse lavage in removing protein, fat and double stranded Deoxyribonucleic acid (dsDNA) from morcellised bone allograft. Twelve donated femoral heads were divided into halves and milled into bone chips. One half of the bone chips were washed with pulse lavage, whereas, the other half acted as control. In order to determine the amount of protein, fat and dsDNA present in the washed and unwashed samples, a validated multistep washing protocol was used. Using the validated technique, simple intra-operative washing of morcellised unprocessed bone allograft removed a significant amount of the protein (70.5%, range: 39.5-85%), fat (95.2%, range: 87.8-98.8%) and DNA (68.4%, range: 31.4-93.1%) content. Intra-operative washing of morcellised bone allograft with pulse lavage may thereby reduce the theoretical risk of prion and other blood borne disease transmission. Combined with the known improved mechanical characteristics of washed allograft, we would recommend pulse lavage as a routine part of bone allograft preparation.

Cryoprecipitation is commonly used as the primary step in the preparation of clinical factor VIII concentrates; yet recovery is usually very low. Much of this loss is due to poor temperature control and a process of continuous plasma thawing has been designed to overcome this. A substantial improvement has resulted, with an increase in both yield and purity of factor VIII :C of over 50% in comparison to a conventional batch thaw process.