A method for detecting plasma soluble fibrin complex, fibrinogen, FDP and γ-dimer using staphylococcal elution technique

Abstract

A new method for detecting fibrinogen related proteins such as fibrin polymer, soluble fibrin complexes (SFC), fibrinogen, early FDP (mainly X), α, β, γ and γ-dimer, was developed by using the technique of adsorption and elution from staphylococci. The procedure of staphylococcal elution technique (SET) was as follows: One tenth ml of sodium citrate plasma was mixed with 2mg of staphylococci and reacted for 10min, washed three times by saline. After washing 0.3ml of 0.05M Tris buffer (pH 11.6) was added and centrifuged. The pH of the resultant supernatant was adjusted to 8.0 by adding 0.05M Tris buffer (pH 6.0). This supernatant (0.2ml) was electrophoresed by SDS-PAGE. After staining and destaining the density of protein band was measured by scanning densitometer.In vitro experiments using purified fibrinogen, FDP-D and FDP-E revealed that fibrinogen, SFC which was made by adding low concentration of thrombin to fibrinogen, and early FDP (mainly X) which was made from the digestion of fibrinogen by plasmin were eluted by SET. Moreover, D and E were also eluted by SET, though the amount of eluted D and E were fairly low.In vitro experiments using normal plasma revealed that eluted normal plasma contained 5 protein bands corresponding to fibrin polymer, fibrinogen and γ-globulin, and probably corresponding to D and E or albumin.Eluted plasma with DIC showed the bands of fibrin polymer, SFC and fibrinogen. Eluted plasma with large dosage of UK therapy showed the bands of fibrin polymer, fibrinogen, partly degraded fibrinogen and FDP-X. The reduction of the eluted normal plasma demonstrated 3 bands which were coincided with α, β, and γ-chain. The reduction of the eluted plasma with DIC demonstrated the bands of γ-dimer (7.1%), α-chain (44.7%), β-chain (27.2%), γ-chain (18.9%) and another bands.Although problems as to precise quantification and as to adsorption and elution of D or E are unsettled, SET would be available for clinic as well as the study of the relation between fibrinogen and its structure.