RESUMEN
The effect of gamma-irradiation on purified prothrombin and thrombin in aqueous solution has been assessed with reference to bifunctional activities, e.g., clotting and esterase functions, physico-chemical changes in structure, and kinetics. The inactivation curves indicated that the clotting activity was more susceptible to gamma-radiation than the esterolytic function in both the proteins. Prothrombin was comparatively more sensitive to radiation than thrombin. The irradiation of prothrombin (100 kR) caused modifications in the protein resulting in reduced formation of thrombin after activation by Factor Xa. The modifications caused by irradiation were assessed in these proteins by changes in spectral characteristics, levels of tryptophan and disulphides, electrophoretic mobility and amino acid composition. Radiation-induced changes in thrombin were reflected in its kinetic behaviour. The clotting activity of thrombin was almost completely lost at 100 kR, while esterolysis was relatively less affected. The modification of tyrosine and tryptophan residues in thrombin influenced the clotting activity, while these were not involved for esterolysis. Histidine had involvement in both these activities.
Asunto(s)
Protrombina/efectos de la radiación , Trombina/efectos de la radiación , Aminoácidos/análisis , Animales , Coagulación Sanguínea/efectos de los fármacos , Bovinos , Relación Dosis-Respuesta en la Radiación , Fibrinógeno/metabolismo , Hidrólisis , Cinética , Espectrometría de Fluorescencia , Tosilarginina Metil Éster/metabolismoAsunto(s)
Factores de Coagulación Sanguínea/efectos de la radiación , Animales , Antitrombina III/metabolismo , Antitrombina III/efectos de la radiación , Factores de Coagulación Sanguínea/metabolismo , Fibrinógeno/metabolismo , Fibrinógeno/efectos de la radiación , Hemorragia/etiología , Antagonistas de Heparina/sangre , Antagonistas de Heparina/efectos de la radiación , Humanos , Protrombina/metabolismo , Protrombina/efectos de la radiación , Traumatismos por Radiación/etiología , SíndromeRESUMEN
The inactivation of HIV by gamma-radiation was studied in frozen and liquid plasma; a reduction of the virus titer of 5 to 6 logs was achieved at doses of 5 to 10 Mrad at -80 degrees C and 2.5 Mrad at 15 degrees C. The effect of irradiation on the biologic activity of a number of coagulation factors in plasma and in lyophilized concentrates of factor VIII (FVIII) and prothrombin complex was examined. A recovery of 85 percent of the biologic activity of therapeutic components present in frozen plasma and in lyophilized coagulation factor concentrates was reached at radiation doses as low as 1.5 and 0.5 Mrad, respectively. As derived from the first-order radiation inactivation curves, the radiosensitive target size of HIV was estimated to be 1 to 3 MDa; the target size of FVIII was estimated to be 130 to 160 kDa. Gamma radiation must be disregarded as a method for the sterilization of plasma and plasma-derived products, because of the low reduction of virus infectivity at radiation doses that still give acceptable recovery of biologic activity of plasma components.