Fibrinogen Philadelphia. A hereditary hypodysfibrinogenemia characterized by fibrinogen hypercatabolism.

A new, autosomally inherited abnormal fibrinogen associated with hypofibrinogenemia has been described in several members of a family. Plasma fibrinogen measured either as thrombin-clottable protein or by immunodiffusion revealed a fibrinogen level ranging between 60 and 90 mg/100 ml. The thrombin time of plasma or purified fibrinogen was prolonged and only partially corrected by the addition of calcium. Purified fibrinogen prolonged the thrombin time of normal plasma. Fibrinopeptide release by thrombin was normal in rate and amount, but fibrin monomer aggregation was grossly disturbed, especially in a high ionic strength medium. We have designated this fibrinogen "fibrinogen Philadelphia." Acrylamide gel electrophoresis of mixtures of [121I]normal and [125I]abnormal fibrinogens revealed a slight increase in the anodal mobility of fibrinogen Philadelphia. Similarly, DEAE-cellulose chromatography showed slightly stronger binding of fibrinogen Philadelphia than normal. To elucidate the mechanism responsible for the low plasma fibrinogen concentration, simultaneous metabolic studies of autologous (patient) and homologous (normal) fibrinogen, labeled with 125I and 121I, respectively, were performed in two affected subjects. Autologous fibrinogen half-life was short and the fractional catabolic rate was markedly increased in both family members. In contrast, homologous fibrinogen half-life and fractional catabolic rate were normal. These metabolic studies demonstrate that rapid degradation of fibrinogen Philadelphia is largely responsible for the depressed levels of a plasma fibrinogen. This represents the first example of a mutant plasma protein in which the molecular defect is associated with an altered catabolism.

Congenital dysprothrombinemia: an inherited structural disorder of human prothrombin.

A large family has been studied, 11 of whose members have half-normal plasma concentrations of biological prothrombin activity. The pattern of inheritance is autosomal. By use of a specific immunoassay, affected family members have been shown to possess normal quantities of immunoreactive prothrombin, whose immunologic properties seem identical with those of the normal zymogen. Prothrombin isolation from the plasma of one such individual gave normal yields of protein but half-normal amounts of prothrombin activity. Activation of this material in the "intrinsic" and "extrinsic" systems, in concentrated sodium citrate, or by trypsin, gives rise to half, or less, of the thrombin clotting and esterase activities expected from a comparable normal prothrombin preparation. During the clotting of blood from an affected individual, all material with the mobility of prothrombin disappears. Immunoelectrophoresis of the serum reveals a normal nonthrombin "pro piece," and an additional activation product with an electrophoretic mobility intermediate between that of prothrombin and of "pro piece." These results suggest that affected individuals are heterozygotes in whom half the prothrombin molecules synthesized are structurally abnormal, since they undergo some alterations during activation, but are incapable of releasing the active enzyme, thrombin.

The total synthesis of phosphatidyl(Dioleoyl)hydroxy-l-proline and its activity in blood-clotting systems.

The phthalimidomethyl ester ofN-anisyloxycarbonyl-hydroxy-L: -proline was combined with phosphorus oxychloride andrac-1,2-diolein. The diolein was made by large-scale preparative application of the method of Krabisch and Borgström (1). The protected phosphatide, obtained by the phosphorylation reaction, was stripped of its protective groups under mild conditions. The phosphatidyl(dioleoyl)-hydroxy-L: -proline was purified by TEAE cellulose (acetate) chromatography, as developed by Rouser (6), also by silicic acid chromatography. Aqueous dispersions of the material were tested for anticoagulant activity in the antithrom-boplastin test and the Hicks-Pitney test. The new phosphatide had about one-tenth of the activity of beef brain phosphatidylserine.

An unsaturated phosphonic acid analogue of phosphatidylethanolamine and its activity in blood-clotting systems.

An unsaturated phosphonolipid analogous to phosphatidylethanolamine,rac-dioleoylglyceryl(2-aminoethyl)phosphonate, was synthesized by a general method introduced by Baer for similar saturated substances. An improvement was made in the preparation of the phthalimidoethyl-phosphonic acid precursor.The phosphonolipid was purified by DEAE cellulose and silicic acid chromatography. It was tested by comparison with synthetic phosphatidyl (dioleoyl) ethanolamine and phosphatidyl(dilinoleoyl) ethanolamine in the Hicks-Pitney test and in a test for prothrombin conversion by using purified blood coagulation factors. In both tests it had more acceleratory activity than the synthetic phosphatidylethanolamines.