title: Some chemical aspects of labeling human fibrinogen with 99m-technetium.
abstract: Human fibrinogen was labeled with 99m-Technetium. Tin(II)-chloride in citric acid served as reducing agent for the pertechnetate-ion, eluted from a Mo-Tc-generator. Before adding the fibrinogen, the citric acid was always neutralized with sodium hydrogen carbonate. The influences on the quantity of fibrinogen bound 99m-Tc of the relative concentrations of Sn(II), fibrinogen and sodium hydrogen carbonate, of the reaction time and temperature were tested by thin-layer chromatography. The reaction temperature of 28 degrees C showed an optimum of fibrinogen bound 99m-Tc for the reaction time from 1 and 2 hours. With a reaction time of 30 minutes not enough 99m-Tc was bound to fibrinogen, the doubling of the reaction time from 1 to 2 hours showed only an increase of binding of less than 4%. The concentration of Sn(II) with respect to the fibrinogen concentration showed no influence on the quantity of fibrinogen bound 99m-Tc at low Sn(II)-concentrations. At values higher than 34 times of the fibrinogen concentration a decrease of the quantity of bound 99m-Tc was observed. The concentrations of sodium hydrogen carbonate showed no influence on the quantity of fibrinogen bound 99m-Tc but on the clottability of fibrinogen, the pH of the solution must be approximately 7.5. In 3 parallel and independent experiments under optimized conditions (1 hour at 28 degrees C, molar ratio of Sn(II) : fibrinogen = 8.5, pH = 7.5) 89.97 +/- 0.92 % of 99 m-Tc were bound to fibrinogen. Controls of these results by column chromatography showed a binding of 81.08 +/- 1.47 % of 99m-Tc to fibrinogen. The clottability of fibrinogen tested by the method of Clauss (1) was entirely preserved.
mesh_terms: D001639:Bicarbonates / Q000494:pharmacology; D005340:Fibrinogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007553:Isotope Labeling / Q000379:methods*; D010689:Phlebitis / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D017693:Sodium Bicarbonate; D013670:Sodium Pertechnetate Tc 99m; D013667:Technetium / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors; D014001:Tin / Q000494:pharmacology; D017971:Tin Compounds
chemical_list: D001639:Bicarbonates; D017971:Tin Compounds; C023599:stannous chloride; D013667:Technetium; D014001:Tin; D017693:Sodium Bicarbonate; D005340:Fibrinogen; D013670:Sodium Pertechnetate Tc 99m